Готові списки джерел за темами / P-wave indices

Добірка наукової літератури з теми "P-wave indices"

Автор: Grafiati

Опубліковано: 14 березня 2023

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями

Оберіть тип джерела:

Зміст

Статті в журналах
Дисертації
Частини книг
Тези доповідей конференцій
Звіти організацій

Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "P-wave indices".

Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.

Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.

Статті в журналах з теми "P-wave indices"

Magnani, Jared W., Mary Ann Williamson, Patrick T. Ellinor, Kevin M. Monahan, and Emelia J. Benjamin. "P Wave Indices." Circulation: Arrhythmia and Electrophysiology 2, no. 1 (February 2009): 72–79. http://dx.doi.org/10.1161/circep.108.806828.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Chhabra, Lovely. "Importance of P-wave indices in stroke." International Journal of Cardiology 203 (January 2016): 962–63. http://dx.doi.org/10.1016/j.ijcard.2015.11.102.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

He, Jinli, Gary Tse, Panagiotis Korantzopoulos, Konstantinos P. Letsas, Sadeq Ali-Hasan-Al-Saegh, Hooman Kamel, Guangping Li, Gregory Y. H. Lip, and Tong Liu. "P-Wave Indices and Risk of Ischemic Stroke." Stroke 48, no. 8 (August 2017): 2066–72. http://dx.doi.org/10.1161/strokeaha.117.017293.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Christos, Goudis A. "P-wave indices in emphysema. What do we actually know?" International Journal of Cardiology 202 (January 2016): 80. http://dx.doi.org/10.1016/j.ijcard.2015.08.150.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Mori, Nobuhito, Risako Kishimoto, and Tomoya Shimura. "WAVE CLIMATE VARIABILITY AND RELATED CLIMATE INDICES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 75. http://dx.doi.org/10.9753/icce.v36.risk.75.

Повний текст джерела

Анотація:

Climate change is highly expected to give significant impact on coastal hazards and environment. The future projections of wave climate under global warming scenarios have been carried out and shows changes in wave heights depending on the regions (e.g., Hemer et al., 2013). Beside the long-term trends of wave climate, annual to decadal changes are also important to understand variability. For example, the North Atlantic Oscillation (NAO) is highly correlated to monthly mean wave height along the western European coast. However, variability of wave climate is not well understood over the globe, quantitatively. Additionally, the standard coastal engineers regard stationary process for wave environment for solving coastal problems. This study analyzes global wave climate variability for the last half century based on principal component analysis of atmospheric forcing (sea surface winds U10 and sea level pressure P) and wave hindcast.

Стилі APA, Harvard, Vancouver, ISO та ін.

Nicoli, Charles D., Margaret Infeld, Sarah Wood, Zachary T. Smith, Sean Meagher, Shawn Wayne, Sherrie Khadanga, and Daniel Lustgarten. "CHANGES IN P-WAVE INDICES FOLLOWING RADIOFREQUENCY ABLATION FOR ATRIAL FIBRILLATION." Journal of the American College of Cardiology 77, no. 18 (May 2021): 260. http://dx.doi.org/10.1016/s0735-1097(21)01619-3.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Gurukripa Kowlgi, N., and Lovely Chhabra. "The role of P-wave indices in the diagnosis of emphysema." International Journal of Cardiology 201 (December 2015): 148–49. http://dx.doi.org/10.1016/j.ijcard.2015.07.093.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Dogan, Umuttan, Nasuh Utku Dogan, Ahmet Ozgur Basarir, Serkan Yildirim, Cetin Celik, Feyzanur Incesu, and Kurtulus Ozdemir. "P-wave parameters and cardiac repolarization indices: Does menopausal status matter?" Journal of Cardiology 60, no. 4 (October 2012): 333–37. http://dx.doi.org/10.1016/j.jjcc.2012.04.001.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Snyder, Michelle L., Elsayed Z. Soliman, Eric A. Whitsel, Kapuaola S. Gellert, and Gerardo Heiss. "Short-term repeatability of electrocardiographic P wave indices and PR interval." Journal of Electrocardiology 47, no. 2 (March 2014): 257–63. http://dx.doi.org/10.1016/j.jelectrocard.2013.11.007.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Tan, Isabella, Hosen Kiat, Edward Barin, Mark Butlin, and Alberto P. Avolio. "Effects of pacing modality on noninvasive assessment of heart rate dependency of indices of large artery function." Journal of Applied Physiology 121, no. 3 (September 1, 2016): 771–80. http://dx.doi.org/10.1152/japplphysiol.00445.2016.

Повний текст джерела

Анотація:

Studies investigating the relationship between heart rate (HR) and arterial stiffness or wave reflections have commonly induced HR changes through in situ cardiac pacing. Although pacing produces consistent HR changes, hemodynamics can be different with different pacing modalities. Whether the differences affect the HR relationship with arterial stiffness or wave reflections is unknown. In the present study, 48 subjects [mean age, 78 ± 10 (SD), 9 women] with in situ cardiac pacemakers were paced at 60, 70, 80, 90, and 100 beats per min under atrial, atrioventricular, or ventricular pacing. At each paced HR, brachial cuff-based pulse wave analysis was used to determine central hemodynamic parameters, including ejection duration (ED) and augmentation index (AIx). Wave separation analysis was used to determine wave reflection magnitude (RM) and reflection index (RI). Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Pacing modality was found to have significant effects on the HR relationship with ED ( P = 0.01), central aortic pulse pressure ( P = 0.01), augmentation pressure ( P < 0.0001), and magnitudes of both forward and reflected waves ( P = 0.05 and P = 0.003, respectively), but not cfPWV ( P = 0.57) or AIx ( P = 0.38). However, at a fixed HR, significant differences in pulse pressure amplification ( P < 0.001), AIx ( P < 0.0001), RM ( P = 0.03), and RI ( P = 0.03) were observed with different pacing modalities. These results demonstrate that although the HR relationships with arterial stiffness and systolic loading as measured by cfPWV and AIx were unaffected by pacing modality, it should still be taken into account for studies in which mixed pacing modalities are present, in particular, for wave reflection studies.

Стилі APA, Harvard, Vancouver, ISO та ін.

Більше джерел

Дисертації з теми "P-wave indices"

Finizola, Francesco. "Clinical aspects and molecular mechanisms of inflammation-driven arrhythmic risk." Doctoral thesis, Università di Siena, 2020. http://hdl.handle.net/11365/1105687.

Повний текст джерела

Анотація:

Increasing evidence indicates systemic inflammation as a new potential cause of acquired LQTS and Torsade de Pointes and a strong predictor of Atrial Fibrillation, via cytokine-mediated changes in cardiomyocyte ion channels and in gap-junction. We hypothesised that systemic inflammation may represent a novel risk factor contributing to TdP development in the general population and can promotes atrial electric remodelling in-vivo, as a result of cytokine-mediated changes in connexins expression. For this reason, two population studies have been designed to confirm these hypotheses. In the first study, forty consecutive patients who experienced TdP (TdP cohort) were consecutively enrolled and circulating levels of C-reactive protein and proinflammatory cytokines (IL-6, TNFα and IL-1) were compared with patients with active rheumatoid arthritis (RA), comorbidity or healthy controls. An additional 46 patients with different inflammatory conditions and elevated CRP (inflammatory cohort) were prospectively enrolled, and corrected QT and cytokine levels were measured during active disease and after a CRP decrease of >75% subsequent to therapy. In the TdP cohort, 80% of patients showed elevated CRP levels (median: ~3 mg/dL). In these subjects, IL-6 was ~15–20 times higher than in controls, and comparable to RA patients. In the inflammatory cohort, where QTc prolongation was common, CRP reduction was associated with IL-6 level decrease and significant QTc shortening. In the second study, fifty-four patients with different inflammatory diseases and elevated C-reactive protein (CRP) levels were prospectively enrolled, and electrocardiographic P-wave dispersion indices, pro-inflammatory cytokine levels (IL-6, TNFα, IL-1), and connexin expression (connexin40, connexin43) were measured during active disease and after reducing CRP by >75%. In addition, peripheral blood mononuclear cells (PBMC) and atrial tissue specimens from 12 patients undergoing cardiac surgery were evaluated for atrial and circulating mRNA levels of connexins. In patients with active inflammatory diseases, P-wave dispersion indices are increased, but rapidly decreased within days when CRP normalizes and IL-6 levels decline. In inflammatory disease patients both P-wave dispersion indices and IL-6 changes are inversely associated with circulating connexins levels, and a positive correlation between connexins expression in PBMC and atrial tissue was demonstrated. Moreover, in-vitro incubation of mouse atrial cardiomyocytes with IL-6 significantly reduces connexins expression. The data are first to show that systemic inflammation via elevated IL-6 levels may represent a novel QT-prolonging risk factor contributing to TdP occurrence. Furthermore, these data suggest that regardless of specific aetiology and organ localization, systemic inflammatory activation, via elevation of IL-6 levels, rapidly induces atrial electrical remodelling by down-regulating cardiac connexins.

Стилі APA, Harvard, Vancouver, ISO та ін.

Частини книг з теми "P-wave indices"

Newnham, Robert E. "Photoelasticity and acousto-optics." In Properties of Materials. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198520757.003.0029.

Повний текст джерела

Анотація:

The change in refractive indices with mechanical stress, the photoelastic effect, is used in analyzing stress patterns in engineering components of complicated shape. It is also important in acousto-optic devices, optical switches, modulators, and scanners in which ultrasonic waves modulate the refractive index, producing an optical grating. Materials with sizable photoelastic coefficients (p) are required to enhance the interaction between mechanical strain x and refractive index n. Changes in the indicatrix are given by These quantities are actually tensors but are treated as scalars in the following discussion which is concerned with the magnitudes of the photoelastic coefficients p, and not their variation with direction. Unlike the linear electro-optic effect, photoelasticity occurs in all symmetry classes and is not a null property. Photoelastic coefficients are dimensionless because strain and refractive index are dimensionless. For most oxides and halides, pmax ≅ 0.2. The maximum values of p measured for other materials range from 0.1 to 0.6. To gain a clearer understanding of the effects of stress on refractive index, consider the effect of hydrostatic pressure on a cubic crystal.

Стилі APA, Harvard, Vancouver, ISO та ін.

Тези доповідей конференцій з теми "P-wave indices"

Bhardwaj, Arya, and J. Sivaraman. "Study of P wave indices in sinus rhythm and tachycardia." In 2021 Seventh International conference on Bio Signals, Images, and Instrumentation (ICBSII). IEEE, 2021. http://dx.doi.org/10.1109/icbsii51839.2021.9445148.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Korkmaz, Nuray. "AN EXAMPLE FOR THE PREDICTION OF THE UNIAXIAL COMPRESSIVE STRENGTH OF WEATHERED ROCKS USING THE WETHERING INDICES BASED ON P-WAVE VELOCITY." In SGEM2011 11th International Multidisciplinary Scientific GeoConference and EXPO. Stef92 Technology, 2011. http://dx.doi.org/10.5593/sgem2011/s02.103.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Hénault, A., R. J. Black, F. Gonthier, S. Lacroix, and M. Cada. "Kerr-type nonlinearities in lightguides: coupled-mode field representations." In Integrated Photonics Research. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/ipr.1990.tuf3.

Повний текст джерела

Анотація:

Third-order nonlinearities in optical waveguides have received considerable recent attention,1 with particular interest in the possibility of devices for all-optical signal processing. In the small-intensity limit (linear case), field decomposition for longitudinally invariant lightguides allows for independently propagating modes, which are wave equation solutions after separation of transverse and longitudinal parts.2,3 For intensity-dependent refractive indices, the illuminated guide is no longer longitudinally invariant, and thus this separation is not permitted. However, as is possible for tapered guides, we can describe the field as a combination of local modes, which couple as the light propagates. As local modes we can use modes of the linear-index guide. Alternatively, we may use solutions of the nonlinear wave equation (NLWE) for the transverse field dependence.4 For approximate monomode propagation this can provide a more natural field representation in particular. However, these modes are only solutions of the transverse NLWE if considered in isolation; i.e., each nonlinear mode modifies the nonlinear index differently. For few-mode propagation, although a coupled nonlinear-local-mode approach may involve fewer local modes depending on the structure, increased complexity in the formalism results when non-orthogonality of the nonlinear modes is accounted for. In contrast, the linear-local-mode treatment has the attraction of simplicity. In Figs. 1-3 we consider the nonlinearly coupled linear-guide local-mode field representation and convergence thereof given initial bimodal excitation, assuming a Kerr-type nonlinear index and slowly varying approximations.3 When we adopt the notation of Ref. 3 with difference between the effective indices of the two initially excited modes δneff, the Kerr coefficient n21, core half-width ρ, and Pref = ρδneff/n2,I, for P/Pref < 1, the two-mode representation is highly accurate for describing the nonlinear phase shifting and small nonlinear coupling. As P/Pref ≈ 1 is approached, the field evolution is well described in terms of 3 or 4 local modes. For P/Pref≥ 2, "violent pulsations"2 are observed, and the local-mode representation may not necessarily be uniformly convergent. These results may be compared with field evolution obtained by using the beam-propagation method.

Стилі APA, Harvard, Vancouver, ISO та ін.

Khachatryan, K. V. "DUST LOAD AS PROBABLE CARDIOVASCULAR RISK FACTOR." In The 4th «OCCUPATION and HEALTH» International Youth Forum (OHIYF-2022). FSBSI «IRIOH», 2022. http://dx.doi.org/10.31089/978-5-6042929-6-9-2022-1-185-189.

Повний текст джерела

Анотація:

Introduction: The impact of harmful occupational factors has adverse effect to human body functional state due to regulatory mechanisms tension, which contributes to occupational diseases and premature aging development. The goal of the work: dust professions workers comparative assessment of cardiovascular risk indicators and elastic properties of vascular wall. Methods: First group included workers exposed to industrial aerosols during work (17 people), second group included workers working out of contact with industrial aerosol (15 people). The groups were comparable by age (53.0±1.43 and 54.7±2.41 years, respectively (p > 0.05). Vascular wall arterial stiffness were assessed by volumetric sphygmography, electrical impedance parameters, indicators of carbohydrate, lipid and nitrogen metabolism, cardiovascular risk assessment carried out by SCORE scale. Results: Working with dust factor, under lower levels of body mass index and lipid spectrum indices, higher indicators of vascular wall stiffness and pulse wave propagation velocity were noted compared to workers without contact with industrial aerosols. Stiffness indicators showed positive relationship with age, urea levels, high-density lipoproteins. Indicators of lipid metabolism (total cholesterol, triglycerides and low-density lipoproteins) showed positive relationship with fat mass level and negative relationship with musculoskeletal mass proportion and specific basal metabolism. Conclusions: There is reason to assume that dust load is probably significant cardiovascular risk factor and may be comparable in importance to traditional risk factors.

Стилі APA, Harvard, Vancouver, ISO та ін.

Aston, Elizabeth, Lidia Meshesha, Angela Stevens, Brian Borsari, and Jane Metrik. "Cannabis Demand and Use among Veterans: A Prospective Examination." In 2021 Virtual Scientific Meeting of the Research Society on Marijuana. Research Society on Marijuana, 2022. http://dx.doi.org/10.26828/cannabis.2022.01.000.20.

Повний текст джерела

Анотація:

Background: Cannabis demand (i.e., relative value), assessed cross-sectionally via a hypothetical marijuana purchase task (MPT), has been associated with cannabis use, problems, and dependence symptoms, among others. However, neither the prospective stability of the MPT, nor the cyclical relationship between demand and use over time has been investigated. Moreover, cannabis demand among cannabis using veterans has yet to be examined. Method: Two waves of data from a veteran sample (N=133) reporting current (past 6-month) cannabis use were analyzed to assess stability and change in cannabis demand over six months. Autoregressive cross-lagged panel models assessed the longitudinal associations between demand indices (i.e., intensity, Omax, Pmax, breakpoint) and cannabis use. Results: Models revealed unique directions of effects for each demand index. Baseline cannabis use predicted greater intensity (ß = .32, p<.001), Omax (ß = .37, p<.001), breakpoint (ß = .28, p<.001), and Pmax (ß = .21, p = .017) at 6-months. Conversely, baseline intensity (ß = .14, p=.028), breakpoint (ß = .12, p=.038), and Pmax (ß = .12, p = .043), but not Omax, predicted greater use at 6-months. Discussion: Cannabis demand indices demonstrated prospective stability over six months and varied along with natural changes in cannabis use. Importantly, intensity, Pmax, and breakpoint displayed bidirectional predictive associations with cannabis use, and across indices, the prospective pathway from use to demand was consistently stronger. Findings highlight the value of assessing cannabis demand longitudinally, particularly among clinical samples, to determine how demand fluctuates in response to experimental manipulation, intervention, and treatment.

Стилі APA, Harvard, Vancouver, ISO та ін.

Wherrett, B. S., J. Bolger, A. K. Kar, I. Galbraith, S. Y. Wang, J. Simpson, K. A. Prior, and B. C. Cavenett. "Picosecond Nonlinear Optics of and Stimulated Emission from n- and p-type MBE ZnSe." In Nonlinear Optics. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/nlo.1992.mc4.

Повний текст джерела

Анотація:

An explosion of interest in ZnSe based optoelectronic devices has followed the reports of diode laser action associated with this material [1,2]. We have, over a period of years, been investigating the nonlinear optical properties of bulk and thin-film ZnSe, initially with concern for all-optical switches and logic elements employing either optothermal or optoelectronic mechanisms. Degenerate-four-wave-mixing, nonlinear Fabry-Perot and z-scan techniques have been employed to measure the absorption cross-sections and induced refractive indices at cw, nanosecond and subpicosecond timescales, with particular concern for near-gap enhancements [3-6].

Стилі APA, Harvard, Vancouver, ISO та ін.

Zhu, Yuliang, Jing Ma та Peipei Dong. "The Improvement of k-ε Model in the Turbulent Wave Boundary Layer". У ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79815.

Повний текст джерела

Анотація:

Numerical model is one of the means for investigating turbulent wave boundary layer. Many scholars have used various eddy-viscosity models to simulate wave turbulent boundary layer flow. On the basis of analyzing existing models, the article uses more reasonable boundary condition to establish an advanced model of turbulent wave boundary layer by k-ε model. Past models have two problems. Firstly, the calculation area is not united since one of the calculation areas is all-water depth and another is boundary layer thickness. Aimed at this problem, this model makes a sensitivity analysis of velocity and eddy-viscosity for various calculation area, which turns out that velocity inside the boundary layer is low-sensitive while the eddy-viscosity is high-sensitive to the change of calculation area. Secondly, a new integration adjust coefficient p is presented to solve the five empirical constants which are difficult to adjust in k-ε model. Although these five empirical constants have recommended value, the universality is not good. In order to obtain better eddy-viscosity value, many methods were suggested to get these five empirical constants, however, most are very complicated. In this article, adjust coefficient p is put before the diffusion item in the velocity equation, and p is a little bit smaller than 1. The result indicates that a reasonable eddy-viscosity can be easily adjusted using this method. The modified model has overcome some shortcomings of the previous models, and gets a better simulation effect.

Стилі APA, Harvard, Vancouver, ISO та ін.

Wachtfogel, Yanina T., Yizhar Floman, Meir Liebergall, Robert W. Colman, and Amiram Eldor. "PLATELET ALPHA2-ADRENERGIC RECEPTOR ABNORMALITIES IN PATIENTS WITH IDIOPATHK: SCOLIOSIS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644567.

Повний текст джерела

Анотація:

Idiopathic scoliosis is a genetic multisystem disease involving skeletal, biochemical, central nervous svstem, muscle and blood platelet abnormalities. Platelets of patients with idiopathic scoliosis have been shown to have decreased adenosine diphosphate and epinephrine-induced aggregation. Similarities between the contractile protein system of platelets and muscle have made the platelet a popular model for certain aspects of muscle physiology. This study confirmed that 64% of the patient platelets tested exhibited a significantly decreased sensitivity to aggregation bv epinephrine. In seven of the eleven patients studied, epinephrine induced aggregation was markedly decreased, i.e., the threshold of agonist was markedly elevated ≥11 uM). The geometric mean concentration of epinephrine required to produce complete second-wave aggregation in idiopathic scoliosis patients was 8μM. as compared to a control concentration of luM. We therefore examined the platelet alpha2-adrenergic receptors of 17 patients with idiopathic scoliosis bv measuring ligand binding using the selective antagonist, methyl yohimbine. Platelets from healthv individuals had 185 ± 16 sites per platelet with a Kd of 1.90 ± 0.32 nM, while patients with idiopathic scoliosis had 54 ± 22 sites per platelet with a of 1.02 ± 0.03 nM. The number of binding sites per platelet in idiopathic scoliosis patients were significantly decreased (p < 0.05) as compared to controls , while the was not significantly different (p > 0.05) between the two groups. Seven of these patients exhibited a significant decrease (p < 0.05) in the number of alpha2-adrenergic receptors on their platelets while the binding in 7 additional patients was undetectable.Three patients exhibited normal receptor number and affinity as compared to normal individuals. This study indicates a profound alteration in the number and function of the alpha2-adrenergic receptors in platelets of patients with idiopathic scoliosis and indicates the functional heterogeneity of the receptor disorder. Further investigation of platelet abnormalities may give insight into the putative muscle defects.

Стилі APA, Harvard, Vancouver, ISO та ін.

Звіти організацій з теми "P-wave indices"

Schetselaar, E. M., G. Bellefleur, and P. Hunt. Integrated analyses of density, P-wave velocity, lithogeochemistry, and mineralogy to investigate effects of hydrothermal alteration and metamorphism on seismic reflectivity: a summary of results from the Lalor volcanogenic massive-sulfide deposit, Snow Lake, Manitoba. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/327999.

Повний текст джерела

Анотація:

We present herein a summary of integrated data analyses aimed at investigating the effects of hydrothermal alteration on seismic reflectivity in the footwall of the Lalor volcanogenic massive-sulfide (VMS) deposit, Manitoba. Multivariate analyses of seismic rock properties, lithofacies, and hydrothermal alteration indices show an increase in P-wave velocity for altered volcanic and volcaniclastic lithofacies with respect to their least-altered equivalents. Scanning electron microscopy-energy dispersive X-ray spectrometry analyses of drill-core samples suggest that this P-wave velocity increase is due to the high abundance of high P-wave velocity aluminous minerals, including cordierite, Fe-Mg amphibole, and garnet, which in volcanic rocks are characteristic of VMS-associated hydrothermal alteration metamorphosed in the amphibolite facies. A seismic synthetic profile computed from a simple amphibolite-facies mineral assemblage model, consisting of mafic-felsic host rock contacts, a sulfide ore lens, and a discordant hydrothermal conduit, show enhanced seismic reflections at conduit-host rock contacts in comparison to the equivalent greenschist facies mineral assemblage model. Collectively our results suggest that VMS footwall hydrothermal alteration zones metamorphosed under middle- to upper-amphibolite facies conditions have enhanced potential for seismic detection.

Стилі APA, Harvard, Vancouver, ISO та ін.

Wideman, Jr., Robert F., Nicholas B. Anthony, Avigdor Cahaner, Alan Shlosberg, Michel Bellaiche, and William B. Roush. Integrated Approach to Evaluating Inherited Predictors of Resistance to Pulmonary Hypertension Syndrome (Ascites) in Fast Growing Broiler Chickens. United States Department of Agriculture, December 2000. http://dx.doi.org/10.32747/2000.7575287.bard.

Повний текст джерела

Анотація:

Background PHS (pulmonary hypertension syndrome, ascites syndrome) is a serious cause of loss in the broiler industry, and is a prime example of an undesirable side effect of successful genetic development that may be deleteriously manifested by factors in the environment of growing broilers. Basically, continuous and pinpointed selection for rapid growth in broilers has led to higher oxygen demand and consequently to more frequent manifestation of an inherent potential cardiopulmonary incapability to sufficiently oxygenate the arterial blood. The multifaceted causes and modifiers of PHS make research into finding solutions to the syndrome a complex and multi threaded challenge. This research used several directions to better understand the development of PHS and to probe possible means of achieving a goal of monitoring and increasing resistance to the syndrome. Research Objectives (1) To evaluate the growth dynamics of individuals within breeding stocks and their correlation with individual susceptibility or resistance to PHS; (2) To compile data on diagnostic indices found in this work to be predictive for PHS, during exposure to experimental protocols known to trigger PHS; (3) To conduct detailed physiological evaluations of cardiopulmonary function in broilers; (4) To compile data on growth dynamics and other diagnostic indices in existing lines selected for susceptibility or resistance to PHS; (5) To integrate growth dynamics and other diagnostic data within appropriate statistical procedures to provide geneticists with predictive indices that characterize resistance or susceptibility to PHS. Revisions In the first year, the US team acquired the costly Peckode weigh platform / individual bird I.D. system that was to provide the continuous (several times each day), automated weighing of birds, for a comprehensive monitoring of growth dynamics. However, data generated were found to be inaccurate and irreproducible, so making its use implausible. Henceforth, weighing was manual, this highly labor intensive work precluding some of the original objectives of using such a strategy of growth dynamics in selection procedures involving thousands of birds. Major conclusions, solutions, achievements 1. Healthy broilers were found to have greater oscillations in growth velocity and acceleration than PHS susceptible birds. This proved the scientific validity of our original hypothesis that such differences occur. 2. Growth rate in the first week is higher in PHS-susceptible than in PHS-resistant chicks. Artificial neural network accurately distinguished differences between the two groups based on growth patterns in this period. 3. In the US, the unilateral pulmonary occlusion technique was used in collaboration with a major broiler breeding company to create a commercial broiler line that is highly resistant to PHS induced by fast growth and low ambient temperatures. 4. In Israel, lines were obtained by genetic selection on PHS mortality after cold exposure in a dam-line population comprising of 85 sire families. The wide range of PHS incidence per family (0-50%), high heritability (about 0.6), and the results in cold challenged progeny, suggested a highly effective and relatively easy means for selection for PHS resistance 5. The best minimally-invasive diagnostic indices for prediction of PHS resistance were found to be oximetry, hematocrit values, heart rate and electrocardiographic (ECG) lead II waves. Some differences in results were found between the US and Israeli teams, probably reflecting genetic differences in the broiler strains used in the two countries. For instance the US team found the S wave amplitude to predict PHS susceptibility well, whereas the Israeli team found the P wave amplitude to be a better valid predictor. 6. Comprehensive physiological studies further increased knowledge on the development of PHS cardiopulmonary characteristics of pre-ascitic birds, pulmonary arterial wedge pressures, hypotension/kidney response, pulmonary hemodynamic responses to vasoactive mediators were all examined in depth. Implications, scientific and agricultural Substantial progress has been made in understanding the genetic and environmental factors involved in PHS, and their interaction. The two teams each successfully developed different selection programs, by surgical means and by divergent selection under cold challenge. Monitoring of the progress and success of the programs was done be using the in-depth estimations that this research engendered on the reliability and value of non-invasive predictive parameters. These findings helped corroborate the validity of practical means to improve PHT resistance by research-based programs of selection.

Стилі APA, Harvard, Vancouver, ISO та ін.

Ми пропонуємо знижки на всі преміум-плани для авторів, чиї праці увійшли до тематичних добірок літератури. Зв'яжіться з нами, щоб отримати унікальний промокод!