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Articles de revues sur le sujet "DZ. None of these, but in this section"
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Fernandez, Jose, Dardo Riveros, Guy Garay, Reinaldo Campestri, Gonzalo Garate, Beatriz Grand, Juan Dupont et Roberto Cacchione. « Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Syndrome) with Transfusion Requirement. Effect of Danazol in 18 Patients with Long Follow-Up. » Blood 104, no 11 (16 novembre 2004) : 1036. http://dx.doi.org/10.1182/blood.v104.11.1036.1036.
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Abstract Hereditary hemorrhagic telangiectasia (HHT) is a relatively uncommon, autosomal dominant disorder characterized by telangiectases that develop in the skin, mucous membranes, and visceral organs. Mucous localization may seldom bleed profusely, especially epistaxis and upper gastrointestinal (GI) tract. Effective drug treatment is not well established, and multiple blood transfusions and endoscopic or surgical procedures may be the ultimate solution to the frequently bleeding HHT patient. Danazol (DZ) is a mild androgen that has been used in small series of HHT pts with ambiguous results. Its toxicity profile in long standing administration is now well known. Eighteen patients with HHT with transfusion requirements (TR) were treated with DZ at 400–600 mg/daily for the initial three months and 200–400 mg/daily thereafter as a maintenance treatment. At the time of initiation of DZ therapy, median age was 54 yr-old (32–73), nine were female and 9 male, and the median previous TR was 16 RBC units/yr. (2–46). All patients had epistaxis and oral cavity bleeding, with 2 additional upper gastrointestinal tract active bleeding that were detected in ten patients in which an upper GI endoscopy was performed. One patient had a cerebral angioma, surgically treated. None had pulmonary fistula. All patients had some kind of iron treatment. DZ was the first drug treatment intended to reduce the HHT bleeding in 10/18 pts. Median follow-up was 7 years (1.2–14) and two pts were lost to follow-up at 4 and 11 years respectively. At three months of DZ therapy, 12/18 pts (66.6%) showed a remarkable reduction of bleeding, and in 6 patients that showed no response, DZ treatment was stopped. In 7 pts (39%) TR dropped to none and in 5 pts median RT dropped from 22 RBC units/yr. to 10 units/yr. Two of responders had a relapse with upper GI tract bleeding and 1 pts with epistaxis within the first 2 years of DZ treatment. Attempts to reduce the maintenance dose below 200 mg/daily were related to new bleeding or worsening of the active sites. None of the long standing DZ therapy had any significant toxicity. DZ treatment have shown efficacy and safety in this cohort of HHT patients. Mecanism of action may involve the increase of synthesis or expression of ALK-1 dependent proteins and less likely of endoglin. We propose DZ as a first line treatment for the transfusion dependent HHT patients.
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Hayakawa, K., T. Shimizu, Y. Ohba, S. Tomioka, S. Takahasi, K. Amano, A. Yura, Y. Yokoyama et Y. Hayakata. « Intrapair Differences of Physical Aging and Longevity in Identical Twins ». Acta geneticae medicae et gemellologiae : twin research 41, no 2-3 (juillet 1992) : 177–85. http://dx.doi.org/10.1017/s0001566000002385.
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AbstractThe genetic and environmental contributions to physical aging (hair graying, balding, presbyopia) and longevity (age at death) were examined by within-pair comparison in monozygotic (MZ) and dizygotic (DZ) twins in later adulthood. Physical aging was investigated on 135 pairs of adult twins aged over 50. Hair graying and hair loss (baldness) showed significantly higher rates of concordance in the MZ twins than in the DZ twins. The intrapair difference of the degree of hair graying was negligible in 79%, slight in 15% and striking in 5% among the MZ pairs; while negligible in 40%, slight in 50% and striking in 10% among the DZ pairs. The intrapair difference of the degree of hair loss was negligible in 92%, slight in 8% (and striking in none) among the MZ pairs; while negligible in 69%, slight in 25% and striking in 6% among the DZ pairs. The age at onset of presbyopia showed a slightly higher rate of concordance in the MZ than in the DZ pairs. Longevity (age at death) was surveyed on 184 pairs of twins who died at over 40 years of age. The intrapair difference of longevity was 6.65 ± 5.6 years (maximum 18.0; minimum 0.04) in the MZ pairs, and 8.66 ± 7.2 years (maximum 18.6; minimum 2.9) in the DZ pairs. The MZ pairs showed a slightly smaller within-pair difference of longevity than the DZ pairs.
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De Berranger, E., G. Vaksmann, E. Thebaud-Leculee, I. Wyckaert, F. Mazingue, C. Francart, J. Dalle et B. Nelken. « Results of randomized study on dexrazoxane administration in children with de novo acute leukemia ». Journal of Clinical Oncology 24, no 18_suppl (20 juin 2006) : 9037. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.9037.
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9037 Background: Anthracyclins and anthracenediones represent major drugs for both AML and ALL. Among other mechanisms, these drugs induce free radical production responsible of cardiac toxicity. It appeared very important to protect cardiomyocytes. Dexrazoxane (DZ) was developed in this goal. In adult patients, its efficiency was demonstrated both to protect heart and to respect anticancer therapy. We conducted a prospective single bind randomized study using DZ in pediatric acute leukemia. Methods: From Dec 00 to Sept 03, 16 patients (pts) were enrolled for receiving or not DZ (1g for 50mg of doxorubicin equivalent dose) with chemotherapy. Cardiac function was evaluated by echocardiogram before induction and after each chemotherapy course of either EORTC 58951 (arm VHR) or LAME01 trials and each year after treatment completion. The cardiologist operator did not know if child received DZ or not. The cumulative equivalent doxorubicin doses were 310 and 450mg/m2 for EORTC 58951 and LAME01, respectively. The primary end-point was cardiac function evolution. The secondary end points were OS, EFS and the respect of therapy schedule. Results: 16 pts (9M/7F, 11AML/5ALL), median age 8.5y (2.4 - 16.1) were enrolled. 5 AML and 3 ALL pts received DZ. Median f-up was 28.5 months (10–47). Mean left ventricular shortening fractions were 39 and 35% in pts without DZ and 40 and 39% in pts with DZ before chemotherapy and 1 year after diagnosis, respectively. Mean wall stress values were 50 and 50g/cm2 for patients without DZ and 39 and 38g/cm2 for pts with DZ. All these values were comparable. 12 pts were alive, 6 in each arm. 1 pt relapsed in DZ arm and 3 in the other arm. 2 pts died of disease and 2 from infection equally dispatched in the 2 arms. Mean time between successive chemotherapy courses was identical in different groups. 2 patients given DZ presented severe hepatic toxicity (≥grade 3 of WHO classification) followed by quick and spontaneous regression. None other toxicity > grade 1 were observed. Conclusions: DZ may be used safely in children receiving anthracycline. No difference in OS and DFS appear in our study. Median follow-up was probably too short for distinguishing any cardiac alteration, and patient number was low. No significant financial relationships to disclose.
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Gupta, Nidhi, Aalia S. Bano, Yogeshwar Sharma, Vikas Sood et Akhil C. Banerjea. « Potent Intracellular Knock Down of Hepatitis B Virus X RNA by Catalytic Hammerhead Ribozymes or DNA-Enzymes with Antisense DNA-Oligonucleotides or 10-23 DNA-Enzymes that Powerfully Augment In Vitro Sequence-Specific Cleavage Activities ». Open Biotechnology Journal 2, no 1 (9 janvier 2008) : 1–12. http://dx.doi.org/10.2174/1874070700802010001.
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Novel antiviral approaches are needed to control Hepatitis B virus infection worldwide. X protein of this virus activates various promoters and is strongly associated with hepatocellular carcinoma. Although several groups, including ours, reported sequence-specific cleavage of X RNA by either ribozymes (Rzs) or DNA-enzymes (Dzs) earlier, but none of these studies reported 100% in vitro cleavage of the full-length X RNA. We reasoned that by melting the secondary structures near the Rz/Dz cleavage site with specific antisense DNA oligonucleotides (ODNs) or 10-23 Dz, it may be possible to achieve this objective. Hammerhead motif containing Rz-170 specific for X RNA was constructed by recombinant techniques and Dz-237 was synthesized using the 10-23 catalytic motif. When specific ODNs or 10-23 Dzs were included in the cleavage reaction with either Rz-170 or Dz-237, increased cleavage was observed in a dose-dependent manner which often resulted in almost complete in vitro cleavage of the target RNA. Rz-170 in combination with specific ODNs caused potent intracellular reduction of HBx RNA. Thus, the cleavage activity of catalytic nucleic acids (Rzs or Dzs) can be increased significantly by specific ODNs or Dzs and this treatment also results in potent intracellular target RNA reduction. These findings have important therapeutic implications.
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Luong, Hien T. T., Justin Chaplin, Allan F. McRae, Sarah E. Medland, Gonneke Willemsen, Dale R. Nyholt, Anjali K. Henders et al. « Variation in BMPR1B, TGFRB1 and BMPR2 and Control of Dizygotic Twinning ». Twin Research and Human Genetics 14, no 5 (1 octobre 2011) : 408–16. http://dx.doi.org/10.1375/twin.14.5.408.
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Genes in the TGF9 signaling pathway play important roles in the regulation of ovarian follicle growth and ovulation rate. Mutations in three genes in this pathway, growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15) and the bone morphogenetic protein receptor B 1 (BMPRB1), influence dizygotic (DZ) twinning rates in sheep. To date, only variants in GDF9 and BMP15, but not their receptors transforming growth factor ß receptor 1 (TGFBR1), bone morphogenetic protein receptor 2 (BMPR2) and BMPR1B, have been investigated with respect to their roles in human DZ twinning. We screened for rare and novel variants in TGFBR1, BMPR2 and BMPR1B in mothers of dizygotic twins (MODZT) from twin-dense families, and assessed association between genotyped and imputed variants and DZ twinning in another large sample of MODZT. Three novel variants were found: a deep intronic variant in BMPR2, and one intronic and one non-synonymous exonic variant in BMPRB1 which would result in the replacement of glutamine by glutamic acid at amino acid position 294 (p.Gln294Glu). None of these variants were predicted to have major impacts on gene function. However, the p.Gln294Glu variant changes the same amino acid as a sheep BMPR1B functional variant and may have functional consequences. Six BMPR1B variants were marginally associated with DZ twinning in the larger case-control sample, but these were no longer significant once multiple testing was taken into account. Our results suggest that variation in the TGF9 signaling pathway type II receptors has limited effects on DZ twinning rates in humans.
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Mackey, Jason, Robert D. Brown, Laura Sauerbeck, Richard Hornung, Charles J. Moomaw, Daniel L. Koller, Tatiana Foroud et al. « Affected Twins in the Familial Intracranial Aneurysm Study ». Cerebrovascular Diseases 39, no 2 (2015) : 82–86. http://dx.doi.org/10.1159/000369961.
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Background and Purpose: Very few cases of intracranial aneurysms (IAs) in twins have been reported. Previous work has suggested that vulnerability to IA formation is heritable. Twin studies provide an opportunity to evaluate the impact of genetics on IA characteristics, including IA location. We therefore sought to examine IA location concordance, multiplicity, and rupture status within affected twin-pairs. Methods: The Familial Intracranial Aneurysm study was a multicenter study whose goal was to identify genetic and other risk factors for formation and rupture of IAs. The study required at least three affected family members or an affected sibling pair for inclusion. Subjects with fusiform aneurysms, an IA associated with an AVM, or a family history of conditions known to predispose to IA formation, such as polycystic kidney disease, Ehlers-Danlos syndrome, Marfan syndrome, fibromuscular dysplasia, or moyamoya syndrome were excluded. Twin-pairs were identified by birth date and were classified as monozygotic (MZ) or dizygotic (DZ) through DNA marker genotypes. In addition to zygosity, we evaluated twin-pairs by smoking status, major arterial territory of IAs, and rupture status. Location concordance was defined as the presence of an IA in the same arterial distribution (ICA, MCA, ACA, and vertebrobasilar), irrespective of laterality, in both members of a twin-pair. The Fisher exact test was used for comparisons between MZ and DZ twin-pairs. Results: A total of 16 affected twin-pairs were identified. Location concordance was observed in 8 of 11 MZ twin-pairs but in only 1 of 5 DZ twin-pairs (p = 0.08). Three MZ subjects had unknown IA locations and comprised the three instances of MZ discordance. Six of the 11 MZ twin-pairs and none of the 5 DZ twin-pairs had IAs in the ICA distribution (p = 0.03). Multiple IAs were observed in 11 of 22 MZ and 5 of 10 DZ twin-pairs. Thirteen (13) of the 32 subjects had an IA rupture, including 10 of 22 MZ twins. Conclusions: We found that arterial location concordance was greater in MZ than DZ twins, which suggests a genetic influence upon aneurysm location. The 16 twin-pairs in the present study are nearly the total of affected twin-pairs that have been reported in the literature to date. Further studies are needed to determine the impact of genetics in the formation and rupture of IAs.
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Allred, Isaac J., et Michael D. Blum. « Early Pennsylvanian sediment routing to the Ouachita Basin (southeastern United States) and barriers to transcontinental sediment transport sourced from the Appalachian orogen based on detrital zircon U-Pb and Hf analysis ». Geosphere 18, no 1 (22 novembre 2021) : 350–69. http://dx.doi.org/10.1130/ges02408.1.
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Abstract Carboniferous sediment dispersal from the Appalachian orogenic system (eastern United States) has become a topic of widespread interest. However, the actual pathways for continental-scale, east-to-west sediment transfer have not been documented. This study presents detrital zircon (DZ) U-Pb ages and Hf isotopic values from the Lower Pennsylvanian (Morrowan) Jackfork Group and Johns Valley Shale of the synorogenic Ouachita deepwater basin of Arkansas to document provenance and delineate the likely sediment-routing systems within the broader context of sediment dispersal across Laurentia. Twelve (12) DZ U-Pb age distributions are interpreted to indicate that sediments were derived from the Appalachians to the east and northeast, as well as the midcontinent region to the north. All samples display prominent ca. 500–400 Ma, 1250–950 Ma, 1550–1300 Ma, and 1800–1600 Ma grains, consistent with ultimate derivation from the Appalachian, Grenville, Midcontinent, and Yavapai-Mazatzal provinces. DZ Hf values obtained from the Ouachita Basin are similar to published Hf values from Pennsylvanian samples in the Appalachian and Illinois Basins. Age distributions are generally consistent for seven samples collected from the Jackfork Group and Johns Valley Shale in the southern Ouachita Mountains through ~2400 m of stratigraphic section and are interpreted to indicate little change in provenance during the Morrowan in this part of the system. However, samples from the most northern and most source-proximal site in Little Rock, Arkansas, exhibit modest percentages of Appalachian ages and elevated contributions of Yavapai-Mazatzal ages when compared with samples collected farther to the south and west. We interpret differences between DZ signatures to indicate distinct sediment-routing pathways to the Ouachita Basin. We infer the strong Appalachian and Grenville signals to represent an axial system flowing through the Appalachian foredeep, whereas the more diverse signals represent a confluence of rivers from the northeast through the backbulge of southern Illinois and western Kentucky and from the north across the Arkoma shelf. Collectively, the Ouachita Basin represents a terminal sink for sediments derived from much of the eastern and central United States.
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KENDLER, KENNETH S., et CHARLES O. GARDNER. « Twin studies of adult psychiatric and substance dependence disorders : are they biased by differences in the environmental experiences of monozygotic and dizygotic twins in childhood and adolescence ? » Psychological Medicine 28, no 3 (mai 1998) : 625–33. http://dx.doi.org/10.1017/s0033291798006643.
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Background. Twin studies have long been used to disentangle the role of genetic and environmental factors in the aetiology of psychiatric disorders. However, the validity of the twin method depends on the equal environment assumption – that monozygotic (MZ) and dizygotic (DZ) twins are equally correlated in their exposure to environmental factors of aetiological importance for the disorder under study.Methods. Both members of 822 female–female twin pairs from a population-based registry previously assessed for a range of psychiatric and substance use disorders were asked 12 questions assessing the similarity of their environmental experiences in childhood and adolescence. We examined whether the similarity of environmental experiences predicted concordance for psychiatric and substance abuse disorders by both a ‘pair-wise’ and ‘individual’ method utilizing logistic regression. We also examined smoking initiation, where prior evidence suggested a role for adolescent social environment.Results. Three factors were derived from these items: ‘Childhood treatment’, ‘Co-socialization’ and ‘Similitude’. Members of twin pairs agreed substantially in their recollections of these experiences. Compared with DZ twins, MZ twins reported comparable resemblance in their childhood treatment, but socialized together more frequently and reported that parents, teachers and friends more commonly emphasized their similarities. None of these three factors significantly predicted twin resemblance for major depression, generalized anxiety disorder, panic disorder, phobias, nicotine dependence or alcohol dependence. However, co-socialization significantly predicted twin resemblance for smoking initiation and perhaps for bulimia.Conclusion. Differential environmental experiences of MZ and DZ twins in childhood and adolescence are unlikely to represent a substantial bias in twin studies of most major psychiatric and substance dependence disorders but may influence twin similarity for the initiation of substance use.
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Tao, X., X. M. Men, B. Deng et Z. W. Xu. « Effects of breed, postnatal development, and nutrition on mRNA expression of the FTO gene in porcine muscle and its relationship with intramuscular fat deposition ». Czech Journal of Animal Science 58, No. 8 (30 juillet 2013) : 381–88. http://dx.doi.org/10.17221/6905-cjas.
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The effects of breed, development, and nutrition on mRNA expression of the fat mass and obesity-associated gene (FTO) and its relationship with intramuscular fat (IMF) content in porcine muscle (m. longissimus dorsi; m.l.d.) were estimated. Purebred Jinhua, Zhongbai, Yorkshire, Duroc, Duroc × Zhongbai (DZ), and Duroc × Yorkshire × Landrace (DYL) pigs were used to investigate the effect of breed. Pigs weighing 2.5, 10, 20, 40, 60, and 100 kg were selected to study the effects of different stages of development. To study the effect of nutrition, four diets were selected: corn-soybean (CS), CS with 1.2% conjugated linoleic acid (CLA) or 0.05% creatine monohydrate (CMH), and barley-soybean (BS). All eighty animals were slaughtered, and m.l.d. samples were collected to examine FTO mRNA expression and IMF content. Results showed that breed significantly affected FTO mRNA expression and IMF content. FTO mRNA expression in the studied pigs was in the order: Zhongbai and Yorkshire > Duroc and DZ > Jinhua and DYL. The IMF content ordered by breed was Duroc > DZ > DYL > Jinhua > Zhongbai > Yorkshire. Both FTO mRNA expression and IMF content increased with age of the pigs, with the greatest difference seen between 100 kg pigs and all other weights. In the study, none of the four diets had a significant effect (P > 0.05) on FTO mRNA expression or IMF content. The study demonstrated that FTO mRNA expression increased with increasing body weight and was significantly affected by the breed of pigs. The results showed that FTO mRNA expression had an inconsistent correlation with IMF content between breeds and developmental ages.
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Pelsmaekers, B., R. Loos, C. Carels, C. Derom et R. Vlietinck. « The Genetic Contribution to Dental Maturation ». Journal of Dental Research 76, no 7 (juillet 1997) : 1337–40. http://dx.doi.org/10.1177/00220345970760070201.
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It has been established in the literature that there is a major genetic impact on tooth size (Potter et al., 1976; Corruccini and Sharma, 1985; Sharma et al., 1985), tooth morphology (Kraus and Furr, 1952; Biggerstaff, 1970), and root formation (Garn et al., 1960; Green and Aszkler, 1970). None of the studies concerning root formation, however, used the more advanced method of path analysis and model fitting to estimate genetic influence. The aim of the present study was to determine the genetic and environmental influence on dental maturation. Dental age scores were determined on panoramic radiographs of 58 pairs of twins-26 monozygotic (MZ) and 32 dizygotic (DZ)-with the method of Demirjian et al. (1973). No mirror-image effect was found between the sides of the same individual or between twin members, so dental maturation seems to be symmetrical for both left and right sides of the mandible. Correlation coefficients were significantly higher in MZ than in DZ twins, which suggests a genetic influence. Model fitting showed that the variation in dental age was best explained by additive genetic influences (A-component) (43%) and by environmental factors common to both twins (C-component) (50%). The specific environment (E-component) added only 8% to the model. The importance of the common environmental factor can be explained by the fact that twins, being raised together, share the same prenatal, natal, and immediate post-natal conditions that are of importance for the formation of the teeth.
Thèses sur le sujet "DZ. None of these, but in this section"
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Ebenezer, Catherine. « “Access denied” ? Barriers for staff accessing, using and sharing published information online within the National Health Service (NHS) in England : technology, risk, culture, policy and practice ». Thesis, University of Sheffield, 2017. http://eprints.rclis.org/32585/1/CME%20thesis%20v4.0%20White%20Rose%20final%20single%20volume.pdf.
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The overall aim of the study was to investigate barriers to online professional information seeking, use and sharing occurring within the NHS in England, their possible effects (upon education, working practices, working lives and clinical and organisational effectiveness), and possible explanatory or causative factors.
The investigation adopted a qualitative case study approach, using semi-structured interviews and documentary analysis as its methods, with three NHS Trusts of different types (acute - district general hospital, mental health / community, acute – teaching) as the nested sites of data collection. It aimed to be both exploratory and explanatory. A stratified sample of participants, including representatives of professions whose perspectives were deemed to be relevant, and clinicians with educational or staff development responsibilities, was recruited for each Trust. Three non-Trust specialists (the product manager of a secure web gateway vendor, an academic e-learning specialist, and the senior manager at NICE responsible for the NHS Evidence electronic content and web platform) were also interviewed. Policy documents, statistics, strategies, reports and quality accounts for the Trusts were obtained via public websites, from participants or via Freedom of Information requests. Thematic analysis following the approach of Braun and Clarke (2006) was adopted as the analytic method for both interviews and documents. The key themes of the results that emerged are presented: barriers to accessing and using information, education and training, professional cultures and norms, information governance and security, and communications policy.
The findings are discussed under three main headings: power, culture, trust and risk in information security; use and regulation of Web 2.0 and social media, and the system of professions. It became evident that the roots of problems with access to and use of such information lay deep within the culture and organisational characteristics of the NHS and its use of IT. A possible model is presented to explain the interaction of the various technical and organisational factors that were identified as relevant. A number of policy recommendations are put forward to improve access to published information at Trust level, as well as recommendations for further research.
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Boyer, Sebastien. « Dans le cadre du nouveau cycle de combustible $^(232)$Th/$^(233)$U, determination de la section efficace de capture radiative $^(233)$Pa(n,$\gamma$) pour des energies de neutrons comprises entre 0 et 1 MeV ». Phd thesis, Université Sciences et Technologies - Bordeaux I, 2004. http://tel.archives-ouvertes.fr/tel-00009062.
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Dans l'optique d'un developpement durable du nucleaire, un des themes de recherche du CNRS dicte par la loi Bataille de 1991, est l'etude d'une nouvelle filiere nucleaire utilisant un combustible a base de minerai de thorium ($^(232)$Th) ou le noyau fissile est l'$^(233)$U. Le principal interet de ce type de combustible reside dans sa particularite de produire les dechets transuraniens en beaucoup plus faible quantite que les reacteurs a eau pressurisee actuels. Cependant certaines donnees nucleaires importantes concernant cette nouvelle filiere sont tres mal connues comme par exemple celles relatives au noyau charniere protactinium 233 ($^(233)$Pa). Sa periode de 27 jours lui confere un role particulier dans le cycle mais en raison de sa trop forte activite l'etude de ce noyau releve du defi experimental. Pour contourner cette difficulte, la probabilite d'emission de rayonnements gamma dans la reaction induite par neutrons $^(233)$Pa(n,$\gamma$) entre 0 et 1 MeV d'energie neutron a ete determinee a partir de la reaction transfert $^(232)Th(^(3)He,p)^(234)Pa*$. Le dispositif de mesure permettait d'identifier la particule de sortie signant ainsi la voie de reaction tandis que des scintillateurs de type C$_(6)$D$_(6)$ permettaient la detection en coincidence des rayonnements gamma emis. La methode d'analyse des evenements gamma a necessite la ponderation des spectres de photons par des fonctions mathematiques calculees dites "fonctions de poids". leurs determinations requierent neanmoins une connaissance parfaite du comportement des scintillateurs (efficacite, fonctions de reponse) dans la geometrie choisie. Pour ce faire, une etude preliminaire a ete realisee a l'aide de sources gamma et avec des reactions induites par protons sur des noyaux legers. Les simulations utilisant le code de transport MCNP ont ete validees par des resultats experimentaux.
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Park, Allison M. « Comparing the Cognitive Demand of Traditional and Reform Algebra 1 Textbooks ». Scholarship @ Claremont, 2011. http://scholarship.claremont.edu/hmc_theses/9.
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Research has shown that students achieved higher standardized test scores in mathematics and gained more positive attitudes towards mathematics after learning from reform curricula. Because these studies involve actual students and teachers, there are classroom variables that are involved in these findings (Silver and Stein, 1996; Stein et al., 1996). To understand how much these curricula by themselves contribute to higher test scores, I have studied the cognitive demand of tasks in two traditional and two reform curricula. This work required the creation of a scale to categorize tasks based on their level of cognitive demand. This scale relates to those by Stein, Schoenfeld, and Bloom. Based on this task analysis, I have found that more tasks in the reform curricula require higher cognitive demand than tasks in the traditional curricula. These findings confirm other results that posing tasks with higher cognitive demand to students can lead to higher student achievement.
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Zurita, Sánchez Juan Manuel. « El paradigma otletiano como base de un modelo para la organización y difusión del conocimiento científico ». Thesis, Universidad Nacional Autónoma de México, 2001. http://eprints.rclis.org/6752/1/tesina._juan_manuel_zurita.pdf.
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Cho, Karina Elle. « Enhancing the Quandle Coloring Invariant for Knots and Links ». Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/hmc_theses/228.
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Quandles, which are algebraic structures related to knots, can be used to color knot diagrams, and the number of these colorings is called the quandle coloring invariant. We strengthen the quandle coloring invariant by considering a graph structure on the space of quandle colorings of a knot, and we call our graph the quandle coloring quiver. This structure is a categorification of the quandle coloring invariant. Then, we strengthen the quiver by decorating it with Boltzmann weights. Explicit examples of links that show that our enhancements are proper are provided, as well as background information in quandle theory.
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Mebane, Palmer. « Uniquely Solvable Puzzles and Fast Matrix Multiplication ». Scholarship @ Claremont, 2012. https://scholarship.claremont.edu/hmc_theses/37.
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In 2003 Cohn and Umans introduced a new group-theoretic framework for doing fast matrix multiplications, with several conjectures that would imply the matrix multiplication exponent $\omega$ is 2. Their methods have been used to match one of the fastest known algorithms by Coppersmith and Winograd, which runs in $O(n^{2.376})$ time and implies that $\omega \leq 2.376$. This thesis discusses the framework that Cohn and Umans came up with and presents some new results in constructing combinatorial objects called uniquely solvable puzzles that were introduced in a 2005 follow-up paper, and which play a crucial role in one of the $\omega = 2$ conjectures.
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Lubisco, Nídia Maria Lienert. « La evaluación en la biblioteca universitaria brasileña : evolución y propuesta de mejora ». Thesis, Universidad Carlos III De Madrid, 2007. http://eprints.rclis.org/12225/1/tesisnidia.pdf.
Texte intégralRésumé :
This thesis examines the evolution of the evaluation of the university library in Brazil. At present, the only applicable system takes place in the evaluation of academic by the Ministry of Education, through the National Institute for Studies and Research Educacionais Anísio Teixeira (INEP), the entity responsible for coordinating and implementing the process of evaluating the entire education system in Brazil. The starting point for addressing this investigation were the results of a case study developed at the Federal University of Bahia in 2001, under the assumption that the Ministry did not have criteria and appropriate instruments to reflect the library's role as a resource for educational qualifications. The review of the literature relevant Brazilian, British and Spanish regarding the subject, especially regarding experience with the Spanish University Libraries Network (REBIUN), were essential to know the trends and the state of affairs. It also took out a field work through questionnaires in 7 countries and 31 Latin American universities, in order to ascertain the current status of evaluation systems used in that region. The low response rate, about 50% of institutions surveyed, this was offset by the work of the Symposium on Electronic Library evaluator and Quality (Sociedad Argentina de report, 2002), an event of great significance to who came over 450 librarians and teachers. This initiative helped develop a comparative study that served to place the Brazilian reality and take into account the most similar case mix. All this enabled comply with the overall objective of this thesis: develop a model to evaluate university libraries in Brazil, from the state of affairs of the university library and Brazilian experiences located in Latin American countries. That model se basa en el Instrument INEP (2006), but its content is raised, taking into account different jobs: performance indicators for assessing the university library, REBIUN (2000), one of the documents PNBU, prepared Romcy by Maria Carmen de Carvalho (1995), Standards for university libraries in Chile (2001) and methodological guide for evaluating the libraries of institutions of higher education (Mexico, 2000). The final claim is that the Brazilian Ministry has a more comprehensive evaluation system, to be implemented and improved according to the data you make and, in turn, could be to build a bank of information management and a system of indicators performance.
8
Moreira, Walter. « A construção de informações documentárias : aportes da linguística documentária, da terminologia e das ontologias ». Thesis, Universidade de São Paulo, 2010. http://eprints.rclis.org/17437/1/TeseFinalRevisada_05Jul2010.pdf.
Texte intégralRésumé :
Investigates theoretical and practical interfaces between terminology, philosophical
ontology, computational ontology and documentary linguistics and the subsidies that they offer for the construction of documentary information. It was established as specific objectives, the analysis of the production, development, implementation and use of ontologies based on the information science theories, the research on the contribution of ontologies for the development of thesauri and vice versa and the discussion of the philosophical foundation of the application of ontologies based on the study of ontological categories present in classical philosophy and in the contemporary proposals. It argues that the understanding of ontologies through the communicative theory of terminology contributes to the organization of a less quantitative access (syntactic) and more qualitative (semantic) of information. Notes that, in spite of sharing some common goals, there is little dialogue between the information science (and, inside it, the documentary linguistics) and computer science. It argues that the computational and philosophical ontologies are not
completely independent events, which have among themselves only the similarity of name,
and notes that the discussion of categories and categorization in computer science, does not always have the emphasis it receives in information science in studies on knowledge
representation. The approach of Deleuze and Guattari's rhizome, was treated as instigator of reflections on the validity of the hierarchical tree model structure and the possibilities of its expansion. It concludes that the construction of ontologies can not ignore the terminological
and conceptual analysis, as it's understood by the terminology and by the information
science accumulated in the theoretical and methodological basis for the construction of
indexing languages and, on the other hand, the construction of flexible indexing languages can not ignore the representational model of ontologies which are more capable for formalization and interoperability.
9
Ollendorff, Christine. « Construction d'un diagnostic complexe d'une bibliothèque académique ». Thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 1999. http://eprints.rclis.org/11682/1/These-co.pdf.
Texte intégralRésumé :
In the first part, we studies academic libraries whose founding principles are change with the information society. The library manager looks for the best ways to lead a library. Evaluation and management tools on libraries are sources of insatisfactions because of the lack of a holistic vision of libraries they give. Constructivist approaches of management seems an alternative way to help library managers in designing a strategic vision of these organizations. In the second part, we build a modelization project with complex systems modelization of Jean-Louis Le Moigne and soft systems methodology of Peter Checkland. French academic libraries constitute our research field in which we use participant observations and staff and managers interviews. Our system is made up of the academic library in the vision of it leader. We build a three phase diagnostic. With the first phase, the manager can observ services supply as a three axes system which evolves with technologies, materials and humans means and bibliotheconomic knowledge. The second phase studies the informational system with environmental and flow observations. The third phase studies the decisional system, looking for its organization, ist internal information circulation and its decisional processes. This diagnostic is in continuous construction. It works in the library management continuity and is not the first step of a strategic planning. We use the diagnostic in five libraries. Results show modelization supply with the creation of evolving, transposable and learning models.
10
Anjos, Anabela. « Bibliomóveis portugueses : diagnóstico de um caso sustentável de extensão biblioteconómica ». Thesis, 2012. http://eprints.rclis.org/19345/1/Tese.pdf.
Texte intégralRésumé :
The mobile services in Portugal are a useful and effective to convey library services
to those who need, who have less means of access to cultural facilities, existing
predominantly in the main cities. It exists some of this services, formerly provided by
Calouste Gulbenkian’s Foundation, but it’s not a reality in the whole country.
We propose a way for the current Portuguese circulating library to expand its
performance, changing their way and adapt to the demands of the knowledge society,
because it is the only way to become dynamic, innovative, competitive and widely
recognized.
In this context, it was important to accomplish the evaluation of these services,
which is justified by the need for constant improvement. This service has to be more
appropriate, efficient and effective.
The implementation of a strategic review following a SWOT helped to prove that
the circulating library should restore itself in the society, following a pro-active and a
dynamic path in the transmission of knowledge.
To identify the dimensions this circulation, we applied a questionnaire to the leaders.
The data analysis was a safe way to seek the reality through the correct facts. And at the
end we can make some proposals and recommendations, to improve the dynamism and
quality of service aspects.
We tried to launch a debate on the future circulating libraries, housed in a quality
public service with modern forms of management of Public Administration, based on a
clear definition of objectives and results to be achieved in methods of networking and
active, collaborative, efficient, speedy, methodology and clear participation. These
systems can be placed on the customer satisfaction and with it, we can, also, be near the
user.
Livres sur le sujet "DZ. None of these, but in this section"
1
Mathematics of probability. Providence, Rhode Island : American Mathematical Society, 2013.
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2
1949-, Libgober A. (Anatoly), Cogolludo-Agustín José Ignacio et Hironaka Eriko 1962-, dir. Topology of algebraic varieties and singularities : Conference in honor of Anatoly Libgober's 60th birthday, June 22-26, 2009, Jaca, Huesca, Spain. Providence, R.I : American Mathematical Society, 2011.
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Center for Mathematics at Notre Dame et American Mathematical Society, dir. Toplogy and field theories : Center for Mathematics at Notre Dame, Center for Mathematics at Notre Dame : summer school and conference, Topology and field theories, May 29-June 8, 2012, University of Notre Dame, Notre Dame, Indiana. Providence, Rhode Island : American Mathematical Society, 2014.
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Ahmed, S. E. (Syed Ejaz), 1957- editor of compilation, dir. Perspectives on big data analysis : Methodologies and applications : International Workshop on Perspectives on High-Dimensional Data Anlaysis II, May 30-June 1, 2012, Centre de Recherches Mathématiques, University de Montréal, Montréal, Québec, Canada. Providence, Rhode Island : American Mathematical Society, 2014.
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Riemann surfaces by way of complex analytic geometry. Providence, R.I : American Mathematical Society, 2011.
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6
Conference Board of the Mathematical Sciences et National Science Foundation (U.S.), dir. Lectures on the energy critical nonlinear wave equation. Providence, Rhode Island : Published for the Conference Board of the Mathematical Sciences by the American Mathematical Society, with support from the National Science Foundation, 2015.
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7
The ultimate challenge : The 3x+1 problem. Providence, R.I : American Mathematical Society, 2010.
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8
From riches to raags : 3-manifolds, right-angled artin groups, and cubical geometry. Providence, Rhode Island : Published for the Conference Board of the Mathematical Sciences by the American Mathematical Society, Providence, Rhode Island with support from the National Science Foundation, 2012.
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Morse, Robert Fitzgerald, editor of compilation, Nikolova-Popova, Daniela, 1952- editor of compilation et Witherspoon, Sarah J., 1966- editor of compilation, dir. Group theory, combinatorics and computing : International Conference in honor of Daniela Nikolova-Popova's 60th birthday on Group Theory, Combinatorics and Computing, October 3-8, 2012, Florida Atlantic University, Boca Raton, Florida. Providence, Rhode Island : American Mathematical Society, 2013.
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Flannery, D. L. (Dane Laurence), 1965-, dir. Algebraic design theory. Providence, R.I : American Mathematical Society, 2011.
Trouver le texte intégralChapitres de livres sur le sujet "DZ. None of these, but in this section"
1
Smithies, Declan. « Luminosity ». Dans The Epistemic Role of Consciousness, 345–79. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780199917662.003.0011.
Texte intégralRésumé :
Chapter 11 defends the thesis that some phenomenal and epistemic conditions are luminous in the sense that you’re always in a position to know whether or not they obtain. Section 11.1 draws a distinction between epistemic and doxastic senses of luminosity and argues that some conditions are epistemically luminous even if none are doxastically luminous. Section 11.2 uses this distinction in solving Ernest Sosa’s version of the problem of the speckled hen. The same distinction is applied to Timothy Williamson’s anti-luminosity argument in section 11.3, his argument against epistemic iteration principles in section 11.4, and his argument for improbable knowing in section 11.5. Section 11.6 concludes by explaining why this defense of luminosity is not merely a pointless compromise.
2
« Literary Selections ». Dans Roots of the Black Chicago Renaissance, sous la direction de Richard A. Courage et Christopher Robert Reed, 245. University of Illinois Press, 2020. http://dx.doi.org/10.5622/illinois/9780252043055.003.0013.
Texte intégralRésumé :
Editors’ Note: Our study concludes with a section comprising three literary selections that we intend to break new ground for a scholarly collection. None of the selections is a conventional academic essay, each belongs to a different genre of writing, and each amplifies the light already shone on the roots of the Black Chicago Renaissance....
3
Phillips, David. « The Critique of Common-Sense Morality (Methods III.I–III.XI) ». Dans Sidgwick's The Methods of Ethics, 96–119. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780197539613.003.0006.
Texte intégralRésumé :
This chapter focuses on The Methods of Ethics, Book III, Chapters I through XI. Its topic is Sidgwick’s critique of the theory he calls “common-sense morality” or “dogmatic intuitionism.” The first section introduces this theory, noting problems with both Sidgwick’s names for it. The second section discusses the project of Chapters I through XI, making the principles of common-sense morality clear and precise. The third section introduces the four conditions Sidgwick uses to test putative axioms. The fourth section outlines his argument that none of the principles of common-sense morality satisfy the four conditions, focusing on the example of promissory obligation. The fifth section considers two responses: defending absolutist deontology, and moving to moderate deontology by introducing, as W. D. Ross does, the concept of prima facie duty. The final section raises questions about the fairness of Sidgwick’s critique.
4
Collins, Richard B., Dale A. Oesterle et Lawrence Friedman. « Schedule ». Dans The Colorado State Constitution, 457–62. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190907723.003.0030.
Texte intégralRésumé :
This chapter discusses the “Schedule” of the Colorado Constitution. Transition to statehood required that territorial institutions and law be retained until expressly replaced. At the end of the original constitution, twenty-two sections under the heading of Schedule detailed how the transition should work. Although almost entirely obsolete, none has been repealed. Schedule Section 1 was invoked by enterprising defense lawyers in efforts to get their clients off on a technicality. At least one succeeded. Section 20, requiring that presidential electors “be chosen by direct vote of the people,” could be read as obsolete or as a continuing constitutional rule. It is the only section with possible relevance to a current dispute.
5
Knee, Jonathan A. « Lessons from Clown School ». Dans Class Clowns, 202–32. Columbia University Press, 2016. http://dx.doi.org/10.7312/columbia/9780231179287.003.0007.
Texte intégralRésumé :
The final section of Class Clowns tries to draw some conclusions from the analyses and case studies. Ten lessons are drawn that should provide guardrails to anyone seeking to play in the education domain. Broadly, the failures highlighted fall into three broad buckets: misguided ambition, misunderstood markets and faulty execution. None of these phenomena are unique to education, but their application takes on a very particular shape in the educational context.
6
Anne Franks, Mary. « “Not Where Bodies Live” ». Dans Free Speech in the Digital Age, 137–49. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190883591.003.0009.
Texte intégralRésumé :
John Perry Barlow, one of the founders of the Electronic Frontier Foundation (EFF), famously claimed in 1996 that the internet “is a world that is both everywhere and nowhere, but it is not where bodies live.” The conception of cyberspace as a realm of pure expression has encouraged an aggressively anti-regulatory approach to the internet. This approach was essentially codified in U.S. federal law in Section 230 of the Communications Decency Act, which invokes free speech principles to provide broad immunity for online intermediaries against liability for the actions of those who use their services. The free speech frame has encouraged an abstract approach to online conduct that downplays its material conditions and impact. Online intermediaries use Section 230 as both a shield and a sword—simultaneously avoiding liability for the speech of others while benefiting from that speech. In the name of free expression, Section 230 allows powerful internet corporations to profit from harmful online conduct while absorbing none of its costs.
7
Schram, Frederick R., et Stefan Koenemann. « Mictacea ». Dans Evolution and Phylogeny of Pancrustacea, 362–69. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780195365764.003.0028.
Texte intégralRésumé :
Mictacea demonstrates the confusion that occurs when animals share so many primitive features. Modest Guţu in fact erected a number of orders to accommodate them, but these do not seem entirely justified. Although the two orders erected by Guţu currently do not have much support, in fairness it must be recognized that molecules, or information from yet-to-be-recognized mictacean taxa, could change the situation. In this case, Guţu’s Bochusacea and Cosinzeneacea might yet prove useful. They inhabit anchialine caves and the deep sea. The animals are small, slender, and subcylindrical in outline. The diagnosis of Guţu to the contrary, none of these animals appear particularly “flattened” in cross-section.
8
Sarch, Alexander. « The Scope of the Willful Ignorance Doctrine (I) ». Dans Criminally Ignorant, 85–108. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190056575.003.0004.
Texte intégralRésumé :
Determining when the equal culpability thesis holds sets the boundaries in which the willful ignorance doctrine is to be applied. Chapter 3 thus considers the best existing attempts to specify the conditions in which the equal culpability thesis holds, but proceeds to argue that none succeeds. Still, each failure is instructive. First, the chapter argues against the unrestricted equal culpability thesis. Not all willful ignorance, it turns out, is as culpable as the analogous knowing misconduct. Then the chapter argues against the three leading attempts to restrict the thesis. Section II argues against a restriction that appeals to bad motives, while Section III argues against a common counterfactual restriction (according to which willful ignorance is as culpable as knowing misconduct when one would do the actus reus even with knowledge). The latter proposal fails since criminal culpability does not depend on considerations about counterfactual conduct or one’s willingness to misbehave. Finally, Section IV discusses a third restriction, offered by Deborah Hellman, which asks whether the decision to remain in ignorance was itself justified. This version of the thesis is on the right track, but still requires refinement in important ways.
9
Fabre, Cécile. « Building Blocks ». Dans Spying Through a Glass Darkly, 12–36. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780198833765.003.0002.
Texte intégralRésumé :
This chapter sets the stage for the remainder of the book. It provides an overview of the ethics of spying in classical moral and political thought. It examines three possible approaches to espionage: (a) the dirty-hands approach, which sees espionage as a necessary evil; (b) the contractarian view that espionage is best defended by appeal to normative conventions endorsed by all; (c) the view that the most fruitful way to construct an ethics of espionage is through the lens of just-war theory. None of those approaches are fully satisfactory, though they provide building blocks for the approach taken in this book. The final section sets out the normative principles on which the book rests.
10
Adams, Robert Merrihew. « God and Possibilities ». Dans What Is, and What Is In Itself, 194–212. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192856135.003.0012.
Texte intégralRésumé :
Section 11.1 of this chapter discusses how (and whether!) God can know all possibilities without actualizing all of them. For if unactualized conscious states and processes are to be permanent objects of actual thoughts in an eternal mind, how different is that from their being actual conscious states and processes of that mind? It is argued that discursive knowledge of logic and mathematics is not problematic in this way—and in section 11.2 that “intuitive” knowledge of qualities raises additional issues, but none that God could not manage. Section 11.3 points out that God does not need to know nearly as much about possibilities if God need not and does not try to create a “best possible world,” but is motivated by grace and love for actual creatures. Section 11.4 addresses two questions about causal explanation: First, the teleological question: “What am I doing, or at least trying to do, and why am I trying to do it?” I think I often know an at least roughly right answer to that question. The second and much harder question is “Why is it that I can do what I am trying to do, if indeed I can?” Occasionalism implies that it depends on God. That is where this line of explanations stops. No causal explanation of God’s omnipotence is on offer.
Actes de conférences sur le sujet "DZ. None of these, but in this section"
1
Allred, Isaac, et Michael Blum. « THERE AND BACK AGAIN : THE RECYCLING OF APPALACHIAN AND GRENVILLE SIGNATURES IN DZ U-PB RECORDS OF PHANEROZOIC NORTH AMERICA ». Dans Joint 56th Annual North-Central/ 71st Annual Southeastern Section Meeting - 2022. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022nc-373575.
Texte intégral
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Al-Shuwaikhat, Hisham I., Shaker A. Al-Buhassan, Turki F. Al-Saadoun et Saad M. Al-Driweesh. « Optimizing Production Facilities Using None-Radio Active Source MPFM in Ghawar Field in Saudi Aramco ». Dans SPE Saudi Arabia section Young Professionals Technical Symposium. Society of Petroleum Engineers, 2008. http://dx.doi.org/10.2118/117063-ms.
Texte intégral
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Brennan, Daniel, Jacob Milton, Paul K. Link et David Pearson. « GEOLOGIC MAPPING AND DZ ANALYSIS OF NEOPROTEROZOIC TO ORDOVICIAN STRATA IN CENTRAL IDAHO REVEALS A THINNER SECTION WITH UNCONFORMITIES, BUT MARGIN-PARALLEL SIMILARITIES IN LITHOSTRATIGRAPHY AND PROVENANCE ». Dans GSA 2020 Connects Online. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020am-357304.
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4
Weaver, Matthew M., Michael G. Dunn et Tab Heffernan. « Experimental Determination of the Influence of Foreign Particle Ingestion on the Behavior of Hot-Section Components Including Lamilloy® ». Dans ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-337.
Texte intégralRésumé :
The effect of foreign particle ingestion on hot-section components has been investigated with a series of experiments performed using a one-quarter sector F100-PW-100 annular combustor. The combustor was operated so that the engine corrected conditions were duplicated. The experiments were designed to determine the influence of cooling hole size, hole roughness (laser-drilled vs. EDM), combustor exit temperature and dust concentration on the cooling capability of the component in the presence of dust particles. Cylindrical Lamilloy® specimens, film cooled Inconel cylinders, and F100-PW-220 first stage turbine vanes were investigated. The size distribution of the foreign particles injected into the air stream just upstream of the combustor was consistent with distributions measured at the exit of high compressors for large turbofan engines. The foreign material was a soil composition representative of materials found around the world. Pre- and post-test bench flow measurements suggested that none of the test specimen’s cooling passages or holes were clogged by the foreign particles. Foreign particle deposition on the specimens was experienced with approximate values for the minimum combustor exit temperature and minimum specimen wall temperature for deposition measured.
5
Urdaneta, Mario, Alfonso Ortega et Russel V. Westphal. « Experiments and Modeling of the Hydraulic Resistance of In-Line Square Pin Fin Heat Sinks With Top By-Pass Flow ». Dans ASME 2003 International Electronic Packaging Technical Conference and Exhibition. ASMEDC, 2003. http://dx.doi.org/10.1115/ipack2003-35268.
Texte intégralRésumé :
Extensive experiments were performed aimed at obtaining physical insight into the behavior of in-line pin fin heat sinks with pins of square cross-section. Detailed pressure measurements were made inside an array of square pins in order to isolate the inlet, developing, fully developed, and exit static pressure distributions as a function of row number. With this as background data, overall pressure drop was measured for a self-consistent set of aluminum heat sinks in side inlet side exit flow, with top clearance only. Pin heights of 12.5 mm, 17.5 mm, and 22.5 mm, pin pitch of 3.4 mm to 6.33 mm, and pin thickness of 1.5 mm, 2 mm and 2.5mm were evaluated. Base dimensions were kept fixed at 25 × 25 mm. In total, 20 aluminum heat sinks were evaluated. A “two-branch by-pass model” was developed, by allowing inviscid acceleration of the flow in the bypass section, and using pressure loss coefficients obtained under no bypass conditions in the heat sink section. The experimental data compared well to the proposed hydraulic models. Measurements in the array of pins showed that full development of the flow occurs after nine rows, thus indicating that none of the heat sinks tested could be characterized as fully-developed.
6
Hu, Kenny S. Y., et Tom I.-P. Shih. « Large-Eddy and RANS Simulations of Heat Transfer in a U-Duct With a High-Aspect Ratio Trapezoidal Cross Section ». Dans ASME Turbo Expo 2018 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75535.
Texte intégralRésumé :
Large-eddy and RANS simulations were performed to examine the details of the heat-transfer mechanisms in a U-duct with a high-aspect ratio trapezoidal cross section at a Reynolds number of 20,000. ANSYS-Fluent was used to perform the simulations. For the large-eddy simulations (LES), the WALE subgrid-scale model was employed, and its inflow boundary condition was provided by a concurrent LES of incompressible fully-developed flow in a straight duct with the same cross section and flow conditions as the U-duct. The grid resolution required to obtain meaningful LES solutions were obtained via a grid sensitivity study of incompressible fully-developed turbulent flow in a straight duct of square cross section, where data from direct numerical simulation (DNS) and experiments are available to validate and guide the simulation. In addition, the grid used satisfies Celik’s criterion, and resolves the Kolmogorov’s −5/3 law. Results were also obtained for the U-duct by using RANS, and three widely used turbulence models were examined — realizable k-ε with the two-layer model in the near-wall region, shear-stress transport (SST) model, and stress-omega full Reynolds stress model (RSM). Results obtained from LES showed unsteady flow separation to occur immediately after the turn region, which none of the RANS models could predict. By being able to capture this unsteady flow mechanism, LES was able to predict the measured heat-transfer downstream of the U-duct. The maximum relative error in the predicted local heat-transfer coefficient was less than 10% in the LES results, but up to 80% in the RANS results.
7
Carroll, L. Blair, et Moe S. Madi. « Crack Detection Program on the Cromer to Gretna, Manitoba Section of Enbridge Pipelines Inc. Line 3 ». Dans 2000 3rd International Pipeline Conference. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/ipc2000-186.
Texte intégralRésumé :
Enbridge Pipelines Inc. Line 3 is an 860mm (34 inch), API 5LX Grade X52 pipeline with nominal wall thickness ranging from 7.14 mm to 12.5 mm. The Canadian portion of the Line runs from Edmonton, Alberta to Gretna, Manitoba. It was constructed between 1963 and 1969 in a series of loops designed to increase the capacity of the Enbridge system. Until 1999 the pipeline operated in a looped configuration with neighboring 24 inch and 48 inch pipelines. Line 3 downstream of Kerrobert, Saskatchewan began operating in straight 34 inch configuration in 1999 following completion of the first phase expansion project known as Terrace Expansion Project that connects the (48 inch) loops with a new (36 inch) pipeline. In 1997, the Pipetronix (now PII) Ultrascan CD in-line inspection tool was run for 283 km from Cromer to Gretna, Manitoba, to identify long seam cracking and pipe body stress corrosion cracking. This section of the line is comprised primarily of pipe manufactured with a double submerged arc welded long seam with short sections of pipe having electric resistance welded long seams. There were two primary objectives set forth in this inspection project. The first was to assess the integrity of this section of Line 3 and identify anomalies, which might affect the future operation of the pipeline. The second objective was to evaluate the performance of the Ultrascan CD tool and determine its potential role in the Enbridge integrity program. A series of excavations have been conducted based upon the analysis of this data and none of the indications identified were considered to be an immediate concern to the integrity of the pipeline. Notably, two of the excavations resulted in the detection of the first two “significant” SCC colonies (based upon the CEPA definition of significant) [1] found on the Enbridge system. This paper will focus on the tool performance requirements established by Enbridge prior to the inspection run which include specific defect type and size and defects at a maximum sensitivity of the tool. In addition, the information obtained as a result of the excavation program and onsite inspection and assessments. The information gathered, from this program were useful in better understanding the tool tolerance in detecting such defects and to better differentiate between them.
8
Bouhairie, Salem, Siddharth Talapatra et Kevin Farrell. « Turbulent Flow in a No-Tube-in-Window Shell-and-Tube Heat Exchanger : CFD vs PIV ». Dans ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36902.
Texte intégralRésumé :
A research-scale shell-and-tube heat exchanger housing a no-tube-in-window (NTIW) arrangement of tubes is analyzed using ANSYS® FLUENT. Three-dimensional, computational fluid dynamic (CFD) simulations of adiabatic flow in a periodic section of the exchanger were conducted. The numerical results were compared to particle image velocimetry (PIV) measurements in the window region where tubes are not present. As part of the study, the k-epsilon with scalable wall function, k-omega with shear stress transport (SST), Reynolds Stress (RSM), and Scale Adaptive Simulation (SAS) turbulence models were assessed. Each turbulence model showed some similarities with the recorded phenomena, but none fully captured the complexity of flow field outside of the tube bundle. Additional simulations of an entire NTIW exchanger model were performed to examine the flow behavior between the window and crossflow regions, as window momentum flux, ρu2, limits are a concern for safe mechanical design.
9
Bajwa, Christopher S., et Earl P. Easton. « Potential Effects of Historic Rail Accidents on the Integrity of Spent Nuclear Fuel Transportation Packages ». Dans ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77811.
Texte intégralRésumé :
The US Nuclear Regulatory Commission (NRC) completed an analysis of historical rail accidents (from 1975 to 2005) involving hazardous materials and long duration fires in the United States. The analysis was initiated to determine what types of accidents had occurred and what impact those types of accidents could have on the rail transport of spent nuclear fuel. The NRC found that almost 21 billion miles of freight rail shipments over a 30 year period had resulted in a small number of accidents involving the release of hazardous materials, eight of which involved long duration fires. All eight of the accidents analyzed resulted in fires that were less severe than the “fully engulfing fire” described as a hypothetical accident condition in the NRC regulations for radioactive material transport found in Title 10 of the Code of Federal Regulations, Part 71, Section 73. None of the eight accidents involved a release of radioactive material. This paper describes the eight accidents in detail and examines the potential effects on spent nuclear fuel transportation packages exposed to the fires that resulted from these accidents.
10
Kochan, P., et H. J. Carmichael. « Photon-statistics dependence of single-atom absorption ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1993. http://dx.doi.org/10.1364/oam.1993.wxx.8.
Texte intégralRésumé :
Under usual laboratory conditions the absorption of a beam of light by a dilute two-level medium depends on the intensity and spectrum of the incident light. If the incident photon flux is small compared to the decay rate of the absorber’s excited state, saturation effects can be neglected and only the spectrum of the light is important; thus, weak-field absorption depends only on the firstorder correlation function of the incident light. This result relies, however, on a requirement that the incident beam cross-section be much larger than the absorption cross-section of an atom. Then individual atoms act as low efficiency scatterers and the statistics of the scattering process is governed by the law of large numbers applied to many scattering sites. In contrast, if it is arranged that just one atom significantly absorbs (scatters) a beam of photons, correlation functions of the incident light beyond the first-order must be considered. For a beam that is focused within an absorption cross-section, we might naively predict that every photon will be scattered and none transmitted. In fact, even for a very weak beam there is a finite probability for two photons to arrive at the atom within the excited state lifetime, and in this event at least one of them will be transmitted (statistical saturation). In this paper we calculate the transmitted photon flux for a weak beam of photons focussed strongly onto a single, resonant two-state atom. We study the dependence of the transmitted flux on the statistics of the incident photons. Photon beams derived from sources of coherent, chaotic, squeezed, coherent-antibunched, and broadband-antibunched light are considered. our calculations are based on a recently developed theory of cascaded open systems,1,2 and serve to illustrate the usefulness of this theory.
Rapports d'organisations sur le sujet "DZ. None of these, but in this section"
1
Adams, Sunny, Madison Story et Adam Smith. Evaluation of 11 buildings in the Fort McCoy cantonment. Engineer Research and Development Center (U.S.), septembre 2022. http://dx.doi.org/10.21079/11681/45350.
Texte intégralRésumé :
The United States Congress codified the National Historic Preservation Act of 1966 (NHPA), the nation’s most effective cultural resources legislation to date, mostly through establishing the National Register of Historic Places (NRHP). The NHPA requires federal agencies to address their cultural resources, which are defined as any prehistoric or historic district, site, building, structure, or object. Section 110 of the NHPA requires federal agencies to inventory and evaluate their cultural resources, and Section 106 requires them to determine the effect of federal undertakings on those potentially eligible for the NRHP. Fort McCoy is in west-central Wisconsin, entirely within Monroe County. It was first established as the Sparta Maneuver Tract in 1909. The post was renamed Camp McCoy in 1926. Since 1974, it has been known as Fort McCoy. This report provides historic context and determinations of eligibility for buildings in the cantonment constructed between 1946 and 1975 and concludes that none are eligible for the NRHP. In consultation with the Wisconsin State Historic Preservation Officer (WISHPO), this work fulfills Section 110 requirements for these buildings.
2
Price, Roz. Climate Adaptation : Lessons and Insights for Governance, Budgeting, and Accountability. Institute of Development Studies (IDS), décembre 2020. http://dx.doi.org/10.19088/k4d.2022.008.
Texte intégralRésumé :
This rapid review draws on literature from academic, policy and non-governmental organisation sources. There is a huge literature on climate governance issues in general, but less is known about effective support and the political-economy of adaptation. A large literature base and case studies on climate finance accountability and budgeting in governments is nascent and growing. Section 2 of this report briefly discusses governance of climate change issues, with a focus on the complexity and cross-cutting nature of climate change compared to the often static organisational landscape of government structured along sectoral lines. Section 3 explores green public financial management (PFM). Section 4 then brings together several principles and lessons learned on green PFM highlighted in the guidance notes. Transparency and accountability lessons are then highlighted in Section 5. The Key findings are: 1) Engaging with the governance context and the political economy of climate governance and financing is crucial to climate objectives being realised. 2) More attention is needed on whether and how governments are prioritising adaptation and resilience in their own operations. 3) Countries in Africa further along in the green PFM agenda give accounts of reform approaches that are gradual, iterative and context-specific, building on existing PFM systems and their functionality. 4) A well-functioning “accountability ecosystem” is needed in which state and non-state accountability actors engage with one another. 5) Climate change finance accountability systems and ecosystems in countries are at best emerging. 6) Although case studies from Nepal, the Philippines and Bangladesh are commonly cited in the literature and are seen as some of the most advanced developing country examples of green PFM, none of the countries have had significant examples of collaboration and engagement between actors. 7) Lessons and guiding principles for green PFM reform include: use the existing budget cycle and legal frameworks; ensure that the basic elements of a functional PFM system are in place; strong leadership of the Ministry of Finance (MoF) and clear linkages with the overall PFM reform agenda are needed; smart sequencing of reforms; real political ownership and clearly defined roles and responsibilities; and good communication to stakeholders).
3
Goeckeritz, Joel, Nathan Schank, Ryan L Wood, Beverly L Roeder et Alonzo D Cook. Use of Urinary Bladder Matrix Conduits in a Rat Model of Sciatic Nerve Regeneration after Nerve Transection Injury. Science Repository, décembre 2022. http://dx.doi.org/10.31487/j.rgm.2022.03.01.
Texte intégralRésumé :
Previous research has demonstrated the use of single-channel porcine-derived urinary bladder matrix (UBM) conduits in segmental-loss, peripheral nerve repairs as comparable to criterion-standard nerve autografts. This study aimed to replicate and expand upon this research with additional novel UBM conduits and coupled therapies. Fifty-four Wistar Albino rats were divided into 6 groups, and each underwent a surgical neurectomy to remove a 7-millimeter section of the sciatic nerve. Bridging of this nerve gap and treatment for each group was as follows: i) reverse autograft—the segmented nerve was reversed 180 degrees and used to reconnect the proximal and distal nerve stumps; ii) the nerve gap was bridged via a silicone conduit; iii) a single-channel UBM conduit; iv) a multi-channel UBM conduit; v) a single-channel UBM conduit identical to group 3 coupled with fortnightly transcutaneous electrical nerve stimulation (TENS); vi) or, a multi-channel UBM conduit identical to group 4 coupled with fortnightly TENS. The extent of nerve recovery was assessed by behavioural parameters: foot fault asymmetry scoring measured weekly for six weeks; electrophysiological parameters: compound muscle action potential (CMAP) amplitudes, measured at weeks 0 and 6; and morphological parameters: total fascicle areas, myelinated fiber counts, fiber densities, and fiber sizes measured at week 6. All the above parameters demonstrated recovery of the test groups (3-6) as being either comparable or less than that of reverse autograft, but none were shown to outperform reverse autograft. As such, UBM conduits may yet prove to be an effective treatment to repair relatively short segmental peripheral nerve injuries, but further research is required to demonstrate greater efficacy over nerve autografts.
4
Goeckeritz, Joel, Nathan Schank, Ryan L Wood, Beverly L Roeder et Alonzo D Cook. Use of Urinary Bladder Matrix Conduits in a Rat Model of Sciatic Nerve Regeneration after Nerve Transection Injury. Science Repository, décembre 2022. http://dx.doi.org/10.31487/j.rgm.2022.03.01.sup.
Texte intégralRésumé :
Previous research has demonstrated the use of single-channel porcine-derived urinary bladder matrix (UBM) conduits in segmental-loss, peripheral nerve repairs as comparable to criterion-standard nerve autografts. This study aimed to replicate and expand upon this research with additional novel UBM conduits and coupled therapies. Fifty-four Wistar Albino rats were divided into 6 groups, and each underwent a surgical neurectomy to remove a 7-millimeter section of the sciatic nerve. Bridging of this nerve gap and treatment for each group was as follows: i) reverse autograft—the segmented nerve was reversed 180 degrees and used to reconnect the proximal and distal nerve stumps; ii) the nerve gap was bridged via a silicone conduit; iii) a single-channel UBM conduit; iv) a multi-channel UBM conduit; v) a single-channel UBM conduit identical to group 3 coupled with fortnightly transcutaneous electrical nerve stimulation (TENS); vi) or, a multi-channel UBM conduit identical to group 4 coupled with fortnightly TENS. The extent of nerve recovery was assessed by behavioural parameters: foot fault asymmetry scoring measured weekly for six weeks; electrophysiological parameters: compound muscle action potential (CMAP) amplitudes, measured at weeks 0 and 6; and morphological parameters: total fascicle areas, myelinated fiber counts, fiber densities, and fiber sizes measured at week 6. All the above parameters demonstrated recovery of the test groups (3-6) as being either comparable or less than that of reverse autograft, but none were shown to outperform reverse autograft. As such, UBM conduits may yet prove to be an effective treatment to repair relatively short segmental peripheral nerve injuries, but further research is required to demonstrate greater efficacy over nerve autografts.
5
Friedler, Haley S., Michelle B. Leavy, Eric Bickelman, Barbara Casanova, Diana Clarke, Danielle Cooke, Andy DeMayo et al. Outcome Measure Harmonization and Data Infrastructure for Patient-Centered Outcomes Research in Depression : Data Use and Governance Toolkit. Agency for Healthcare Research and Quality (AHRQ), octobre 2021. http://dx.doi.org/10.23970/ahrqepcwhitepaperdepressiontoolkit.
Texte intégralRésumé :
Executive Summary Patient registries are important tools for advancing research, improving healthcare quality, and supporting health policy. Registries contain vast amounts of data that could be used for new purposes when linked with other sources or shared with researchers. This toolkit was developed to summarize current best practices and provide information to assist registries interested in sharing data. The contents of this toolkit were developed based on review of the literature, existing registry practices, interviews with registries, and input from key stakeholders involved in the sharing of registry data. While some information in this toolkit may be relevant in other countries, this toolkit focuses on best practices for sharing data within the United States. Considerations related to data sharing differ across registries depending on the type of registry, registry purpose, funding source(s), and other factors; as such, this toolkit describes general best practices and considerations rather than providing specific recommendations. Finally, data sharing raises complex legal, regulatory, operational, and technical questions, and none of the information contained herein should be substituted for legal advice. The toolkit is organized into three sections: “Preparing to Share Data,” “Governance,” and “Procedures for Reviewing and Responding to Data Requests.” The section on “Preparing to Share Data” discusses the role of appropriate legal rights to further share the data and the need to follow all applicable ethical regulations. Registries should also prepare for data sharing activities by ensuring data are maintained appropriately and developing policies and procedures for governance and data sharing. The “Governance” section describes the role of governance in data sharing and outlines key governance tasks, including defining and staffing relevant oversight bodies; developing a data request process; reviewing data requests; and overseeing access to data by the requesting party. Governance structures vary based on the scope of data shared and registry resources. Lastly, the section on “Procedures for Reviewing and Responding to Data Requests” discusses the operational steps involved in sharing data. Policies and procedures for sharing data may depend on what types of data are available for sharing and with whom the data can be shared. Many registries develop a data request form for external researchers interested in using registry data. When reviewing requests, registries may consider whether the request aligns with the registry’s mission/purpose, the feasibility and merit of the proposed research, the qualifications of the requestor, and the necessary ethical and regulatory approvals, as well as administrative factors such as costs and timelines. Registries may require researchers to sign a data use agreement or other such contract to clearly define the terms and conditions of data use before providing access to the data in a secure manner. The toolkit concludes with a list of resources and appendices with supporting materials that registries may find helpful.
6
Friedler, Haley S., Michelle B. Leavy, Eric Bickelman, Barbara Casanova, Diana Clarke, Danielle Cooke, Andy DeMayo et al. Outcome Measure Harmonization and Data Infrastructure for Patient-Centered Outcomes Research in Depression : Data Use and Governance Toolkit. Agency for Healthcare Research and Quality (AHRQ), octobre 2021. http://dx.doi.org/10.23970/ahrqepcwhitepaperdepressiontoolkit.
Texte intégralRésumé :
Executive Summary Patient registries are important tools for advancing research, improving healthcare quality, and supporting health policy. Registries contain vast amounts of data that could be used for new purposes when linked with other sources or shared with researchers. This toolkit was developed to summarize current best practices and provide information to assist registries interested in sharing data. The contents of this toolkit were developed based on review of the literature, existing registry practices, interviews with registries, and input from key stakeholders involved in the sharing of registry data. While some information in this toolkit may be relevant in other countries, this toolkit focuses on best practices for sharing data within the United States. Considerations related to data sharing differ across registries depending on the type of registry, registry purpose, funding source(s), and other factors; as such, this toolkit describes general best practices and considerations rather than providing specific recommendations. Finally, data sharing raises complex legal, regulatory, operational, and technical questions, and none of the information contained herein should be substituted for legal advice. The toolkit is organized into three sections: “Preparing to Share Data,” “Governance,” and “Procedures for Reviewing and Responding to Data Requests.” The section on “Preparing to Share Data” discusses the role of appropriate legal rights to further share the data and the need to follow all applicable ethical regulations. Registries should also prepare for data sharing activities by ensuring data are maintained appropriately and developing policies and procedures for governance and data sharing. The “Governance” section describes the role of governance in data sharing and outlines key governance tasks, including defining and staffing relevant oversight bodies; developing a data request process; reviewing data requests; and overseeing access to data by the requesting party. Governance structures vary based on the scope of data shared and registry resources. Lastly, the section on “Procedures for Reviewing and Responding to Data Requests” discusses the operational steps involved in sharing data. Policies and procedures for sharing data may depend on what types of data are available for sharing and with whom the data can be shared. Many registries develop a data request form for external researchers interested in using registry data. When reviewing requests, registries may consider whether the request aligns with the registry’s mission/purpose, the feasibility and merit of the proposed research, the qualifications of the requestor, and the necessary ethical and regulatory approvals, as well as administrative factors such as costs and timelines. Registries may require researchers to sign a data use agreement or other such contract to clearly define the terms and conditions of data use before providing access to the data in a secure manner. The toolkit concludes with a list of resources and appendices with supporting materials that registries may find helpful.
7
Stavland, Arne, Siv Marie Åsen, Arild Lohne, Olav Aursjø et Aksel Hiorth. Recommended polymer workflow : Lab (cm and m scale). University of Stavanger, novembre 2021. http://dx.doi.org/10.31265/usps.201.
Texte intégralRésumé :
Polymer flooding is one of the most promising EOR methods (Smalley et al. 2018). It is well known and has been used successfully (Pye 1964; Standnes & Skjevrak 2014; Sheng et al. 2015). From a technical perspective we recommend that polymer flooding should be considered as a viable EOR method on the Norwegian Continental Shelf for the following reasons: 1. More oil can be produced with less water injected; this is particularly important for the NCS which are currently producing more water than oil 2. Polymers will increase the aerial sweep and improve the ultimate recovery, provided a proper injection strategy 3. Many polymer systems are available, and it should be possible to tailor their chemical composition to a wide range of reservoir conditions (temperature and salinity) 4. Polymer systems can be used to block water from short circuiting injection production wells 5. Polymer combined with low salinity injection water has many benefits: a lower polymer concentration can be used to reach target viscosity, less mechanical degradation, less adsorption, and a potential reduction in Sor due to a low salinity wettability effect. There are some hurdles when considering polymer flooding that needs to be considered: 1. Many polymer systems are not at the present considered as green chemicals; thus, reinjection of produced water is needed. However, results from polymer degradation studies in the IORCentre indicates that a. High molecular weight polymers are quickly degraded to low molecular weight. In case of accidental release to the ocean low molecular weight polymers are diluted and the lifetime of the spill might be quite short. According to Caulfield et al. (2002) HPAM is not toxic, and will not degrade to the more environmentally problematic acrylamide. b. In the DF report for environmental impact there are case studies using the DREAM model to predict the transport of chemical spills. This model is coupled with polymer (sun exposure) degradation data from the IORCentre to quantify the lifetime of polymer spills. This approach should be used for specific field cases to quantify the environmental risk factor. 2. Care must be taken to prepare the polymer solution offshore. Chokes and vales might be a challenge but can be mitigating according to the results from the large-scale testing done in the IORCentre (Stavland et al. 2021). None of the above-mentioned challenges are server enough to not consider polymer flooding. HPAM is neither toxic, nor bio-accumulable, or bio-persistent and the CO2 footprint from a polymer flood may be significantly less than a water flood (Dupuis et al. 2021). There are at least two contributing factors to this statement, which we will return in detail to in the next section i) during linear displacement polymer injection will produce more oil for the same amount of water injected, hence the lifetime of the field can be shortened ii) polymers increase the arial sweep reducing the need for wells.
8
Mazzoni, Silvia, Nicholas Gregor, Linda Al Atik, Yousef Bozorgnia, David Welch et Gregory Deierlein. Probabilistic Seismic Hazard Analysis and Selecting and Scaling of Ground-Motion Records (PEER-CEA Project). Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, novembre 2020. http://dx.doi.org/10.55461/zjdn7385.
Texte intégralRésumé :
This report is one of a series of reports documenting the methods and findings of a multi-year, multi-disciplinary project coordinated by the Pacific Earthquake Engineering Research Center (PEER) and funded by the California Earthquake Authority (CEA). The overall project is titled “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.” The overall objective of the PEER–CEA Project is to provide scientifically based information (e.g., testing, analysis, and resulting loss models) that measure and assess the effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of wood-frame houses with cripple wall and sill anchorage deficiencies as well as retrofitted conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance of wood-frame houses; (2) identifying construction features to characterize alternative variants of wood-frame houses; (3) characterizing earthquake hazard and ground motions at representative sites in California; (4) developing cyclic loading protocols and conducting laboratory tests of cripple wall panels, wood-frame wall subassemblies, and sill anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors. This report is a product of Working Group 3 (WG3), Task 3.1: Selecting and Scaling Ground-motion records. The objective of Task 3.1 is to provide suites of ground motions to be used by other working groups (WGs), especially Working Group 5: Analytical Modeling (WG5) for Simulation Studies. The ground motions used in the numerical simulations are intended to represent seismic hazard at the building site. The seismic hazard is dependent on the location of the site relative to seismic sources, the characteristics of the seismic sources in the region and the local soil conditions at the site. To achieve a proper representation of hazard across the State of California, ten sites were selected, and a site-specific probabilistic seismic hazard analysis (PSHA) was performed at each of these sites for both a soft soil (Vs30 = 270 m/sec) and a stiff soil (Vs30=760 m/sec). The PSHA used the UCERF3 seismic source model, which represents the latest seismic source model adopted by the USGS [2013] and NGA-West2 ground-motion models. The PSHA was carried out for structural periods ranging from 0.01 to 10 sec. At each site and soil class, the results from the PSHA—hazard curves, hazard deaggregation, and uniform-hazard spectra (UHS)—were extracted for a series of ten return periods, prescribed by WG5 and WG6, ranging from 15.5–2500 years. For each case (site, soil class, and return period), the UHS was used as the target spectrum for selection and modification of a suite of ground motions. Additionally, another set of target spectra based on “Conditional Spectra” (CS), which are more realistic than UHS, was developed [Baker and Lee 2018]. The Conditional Spectra are defined by the median (Conditional Mean Spectrum) and a period-dependent variance. A suite of at least 40 record pairs (horizontal) were selected and modified for each return period and target-spectrum type. Thus, for each ground-motion suite, 40 or more record pairs were selected using the deaggregation of the hazard, resulting in more than 200 record pairs per target-spectrum type at each site. The suites contained more than 40 records in case some were rejected by the modelers due to secondary characteristics; however, none were rejected, and the complete set was used. For the case of UHS as the target spectrum, the selected motions were modified (scaled) such that the average of the median spectrum (RotD50) [Boore 2010] of the ground-motion pairs follow the target spectrum closely within the period range of interest to the analysts. In communications with WG5 researchers, for ground-motion (time histories, or time series) selection and modification, a period range between 0.01–2.0 sec was selected for this specific application for the project. The duration metrics and pulse characteristics of the records were also used in the final selection of ground motions. The damping ratio for the PSHA and ground-motion target spectra was set to 5%, which is standard practice in engineering applications. For the cases where the CS was used as the target spectrum, the ground-motion suites were selected and scaled using a modified version of the conditional spectrum ground-motion selection tool (CS-GMS tool) developed by Baker and Lee [2018]. This tool selects and scales a suite of ground motions to meet both the median and the user-defined variability. This variability is defined by the relationship developed by Baker and Jayaram [2008]. The computation of CS requires a structural period for the conditional model. In collaboration with WG5 researchers, a conditioning period of 0.25 sec was selected as a representative of the fundamental mode of vibration of the buildings of interest in this study. Working Group 5 carried out a sensitivity analysis of using other conditioning periods, and the results and discussion of selection of conditioning period are reported in Section 4 of the WG5 PEER report entitled Technical Background Report for Structural Analysis and Performance Assessment. The WG3.1 report presents a summary of the selected sites, the seismic-source characterization model, and the ground-motion characterization model used in the PSHA, followed by selection and modification of suites of ground motions. The Record Sequence Number (RSN) and the associated scale factors are tabulated in the Appendices of this report, and the actual time-series files can be downloaded from the PEER Ground-motion database Portal (https://ngawest2.berkeley.edu/)(link is external).
9
Jorgensen, Frieda, Andre Charlett, Craig Swift, Anais Painset et Nicolae Corcionivoschi. A survey of the levels of Campylobacter spp. contamination and prevalence of selected antimicrobial resistance determinants in fresh whole UK-produced chilled chickens at retail sale (non-major retailers). Food Standards Agency, juin 2021. http://dx.doi.org/10.46756/sci.fsa.xls618.
Texte intégralRésumé :
Campylobacter spp. are the most common bacterial cause of foodborne illness in the UK, with chicken considered to be the most important vehicle for this organism. The UK Food Standards Agency (FSA) agreed with industry to reduce Campylobacter spp. contamination in raw chicken and issued a target to reduce the prevalence of the most contaminated chickens (those with more than 1000 cfu per g chicken neck skin) to below 10 % at the end of the slaughter process, initially by 2016. To help monitor progress, a series of UK-wide surveys were undertaken to determine the levels of Campylobacter spp. on whole UK-produced, fresh chicken at retail sale in the UK. The data obtained for the first four years was reported in FSA projects FS241044 (2014/15) and FS102121 (2015 to 2018). The FSA has indicated that the retail proxy target for the percentage of highly contaminated raw whole retail chickens should be less than 7% and while continued monitoring has demonstrated a sustained decline for chickens from major retailer stores, chicken on sale in other stores have yet to meet this target. This report presents results from testing chickens from non-major retailer stores (only) in a fifth survey year from 2018 to 2019. In line with previous practise, samples were collected from stores distributed throughout the UK (in proportion to the population size of each country). Testing was performed by two laboratories - a Public Health England (PHE) laboratory or the Agri-Food & Biosciences Institute (AFBI), Belfast. Enumeration of Campylobacter spp. was performed using the ISO 10272-2 standard enumeration method applied with a detection limit of 10 colony forming units (cfu) per gram (g) of neck skin. Antimicrobial resistance (AMR) to selected antimicrobials in accordance with those advised in the EU harmonised monitoring protocol was predicted from genome sequence data in Campylobacter jejuni and Campylobacter coli isolates The percentage (10.8%) of fresh, whole chicken at retail sale in stores of smaller chains (for example, Iceland, McColl’s, Budgens, Nisa, Costcutter, One Stop), independents and butchers (collectively referred to as non-major retailer stores in this report) in the UK that are highly contaminated (at more than 1000 cfu per g) with Campylobacter spp. has decreased since the previous survey year but is still higher than that found in samples from major retailers. 8 whole fresh raw chickens from non-major retailer stores were collected from August 2018 to July 2019 (n = 1009). Campylobacter spp. were detected in 55.8% of the chicken skin samples obtained from non-major retailer shops, and 10.8% of the samples had counts above 1000 cfu per g chicken skin. Comparison among production plant approval codes showed significant differences of the percentages of chicken samples with more than 1000 cfu per g, ranging from 0% to 28.1%. The percentage of samples with more than 1000 cfu of Campylobacter spp. per g was significantly higher in the period May, June and July than in the period November to April. The percentage of highly contaminated samples was significantly higher for samples taken from larger compared to smaller chickens. There was no statistical difference in the percentage of highly contaminated samples between those obtained from chicken reared with access to range (for example, free-range and organic birds) and those reared under standard regime (for example, no access to range) but the small sample size for organic and to a lesser extent free-range chickens, may have limited the ability to detect important differences should they exist. Campylobacter species was determined for isolates from 93.4% of the positive samples. C. jejuni was isolated from the majority (72.6%) of samples while C. coli was identified in 22.1% of samples. A combination of both species was found in 5.3% of samples. C. coli was more frequently isolated from samples obtained from chicken reared with access to range in comparison to those reared as standard birds. C. jejuni was less prevalent during the summer months of June, July and August compared to the remaining months of the year. Resistance to ciprofloxacin (fluoroquinolone), erythromycin (macrolide), tetracycline, (tetracyclines), gentamicin and streptomycin (aminoglycosides) was predicted from WGS data by the detection of known antimicrobial resistance determinants. Resistance to ciprofloxacin was detected in 185 (51.7%) isolates of C. jejuni and 49 (42.1%) isolates of C. coli; while 220 (61.1%) isolates of C. jejuni and 73 (62.9%) isolates of C. coli isolates were resistant to tetracycline. Three C. coli (2.6%) but none of the C. jejuni isolates harboured 23S mutations predicting reduced susceptibility to erythromycin. Multidrug resistance (MDR), defined as harbouring genetic determinants for resistance to at least three unrelated antimicrobial classes, was found in 10 (8.6%) C. coli isolates but not in any C. jejuni isolates. Co-resistance to ciprofloxacin and erythromycin was predicted in 1.7% of C. coli isolates. 9 Overall, the percentages of isolates with genetic AMR determinants found in this study were similar to those reported in the previous survey year (August 2016 to July 2017) where testing was based on phenotypic break-point testing. Multi-drug resistance was similar to that found in the previous survey years. It is recommended that trends in AMR in Campylobacter spp. isolates from retail chickens continue to be monitored to realise any increasing resistance of concern, particulary to erythromycin (macrolide). Considering that the percentage of fresh, whole chicken from non-major retailer stores in the UK that are highly contaminated (at more than 1000 cfu per g) with Campylobacter spp. continues to be above that in samples from major retailers more action including consideration of interventions such as improved biosecurity and slaughterhouse measures is needed to achieve better control of Campylobacter spp. for this section of the industry. The FSA has indicated that the retail proxy target for the percentage of highly contaminated retail chickens should be less than 7% and while continued monitoring has demonstrated a sustained decline for chickens from major retailer stores, chicken on sale in other stores have yet to meet this target.