Journal articles on the topic 'Diffusal population'
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Isaac, Wendy-Ann P., Richard A. I. Brathwaite, and Ayub Khan. "Commelina diffusaPopulation Dynamics in Banana and Ruderal Habitats under Mechanical and Herbicide Management Regimes." International Journal of Agronomy 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/605745.
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Commelina diffusais a colonising species of banana orchard habitats in St. Vincent in the Windward Islands of the Caribbean. In the present study, the population dynamics ofC. diffusawere investigated in response to mechanical weed management with either a rotary string trimmer or glufosinate in ruderal and banana habitats. The study focused on density and size distribution of the weed over time and their response to two weed management strategies. The population dynamics ofC. diffusadiffered between the two habitats. Seedling establishment appeared to be an important factor influencing the dynamics ofC. diffusain banana orchards as there was little recruitment of seeds with less flower production compared with ruderal habitats where plants produced more flowers. Plants ofC. diffusain the banana orchard habitat had a longer growth cycle. In the banana orchard habitat, theC. diffusapopulation was greater and the plants were shorter with mechanical management than in areas treated with glufosinate. The results suggest that it is possible to manipulate the dynamics ofC. diffusain banana orchards as there is less chance of seed recruitment. Further research is necessary to refine an IPM approach for the management ofC. diffusa.
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Wilson, Rob, K. George Beck, and Philip Westra. "Combined effects of herbicides and Sphenoptera jugoslavica on diffuse knapweed (Centaurea diffusa) population dynamics." Weed Science 52, no. 3 (May 2004): 418–23. http://dx.doi.org/10.1614/p2001-061.
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Sosnovska, Svitlana, and Ivan Danylyk. "Population structure of Carex dioica L. (Cyperaceae) in Ukraine under different growth conditions." Biodiversity Research and Conservation 46, no. 1 (June 1, 2017): 19–33. http://dx.doi.org/10.1515/biorc-2017-0006.
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Abstract The population structure of Carex dioica – a rare boggy species in Ukraine – has been studied for the first time. As a result, five types of spatial arrangement of C. dioica individuals, depending on their reproduction and living conditions, were established: scattered-diffuse, densely-diffuse, group, spotted and mosaic. Intensive vegetative propagation (often in the absence of seed reproduction) of individuals contributes to the group and spotted spatial structure of population. For low intensity of seed and vegetative reproduction, the arrangement of generative individuals turned out to be scattered-diffuse. Effective generative reproduction of a population was accompanied by a densely-diffuse distribution of individuals, and a combined type of reproduction (effective generative and vegetative) under favourable growth conditions contributes to its mosaic spatial structure. Regardless of the growth conditions, all C. dioica populations were characterised by a left-hand age spectrum which was the result of an effective vegetative renovation of individuals and a stress-tolerant type of strategy of this species. Under optimal growth conditions, the C. dioica populations were characterised by the prevalance of females compared to male ones (2:1), and under stress – a radical change in their sex ratio was observed towards a complete dominance of one of the genders. It was found that 50% of the studied C. dioica populations appeared to be thriving. Regardless of the vitality type of the population, the female individuals of this species, compared to male ones, realised their growth potential much better and, therefore, made a greater contribution to population vitality.
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Arnaboldi, Magda. "Intracluster Stellar Population." Symposium - International Astronomical Union 217 (2004): 54–63. http://dx.doi.org/10.1017/s007418090019713x.
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I shall review the latest results for the presence of diffuse light in nearby clusters, and the evidence of ongoing star formation in an intracluster Virgo field. I shall discuss how intracluster planetary nebulae (ICPN) can be used as excellent tracers of the diffuse stellar population in nearby clusters. Their number density distribution, density profile and radial velocity distribution provide observational constraints to models for cluster formation and evolution. The preliminary comparison of the available ICPN samples with high resolution N-body models of a Virgo-like cluster in a Lambda CDM cosmology supports “harassment” as the most likely mechanism for the origin of diffuse stellar light in clusters.
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Mueller, Ulrich G., Alexander S. Mikheyev, Scott E. Solomon, and Michael Cooper. "Frontier mutualism: coevolutionary patterns at the northern range limit of the leaf-cutter ant–fungus symbiosis." Proceedings of the Royal Society B: Biological Sciences 278, no. 1721 (March 9, 2011): 3050–59. http://dx.doi.org/10.1098/rspb.2011.0125.
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Tropical leaf-cutter ants cultivate the fungus Attamyces bromatificus in a many-to-one, diffuse coevolutionary relationship where ant and fungal partners re-associate frequently over time. To evaluate whether ant– Attamyces coevolution is more specific (tighter) in peripheral populations, we characterized the host-specificities of Attamyces genotypes at their northern, subtropical range limits (southern USA, Mexico and Cuba). Population-genetic patterns of northern Attamyces reveal features that have so far not been observed in the diffusely coevolving, tropical ant– Attamyces associations. These unique features include (i) cases of one-to-one ant– Attamyces specialization that tighten coevolution at the northern frontier; (ii) distributions of genetically identical Attamyces clones over large areas (up to 81 000 km 2 , approx. the area of Ireland, Austria or Panama); (iii) admixture rates between Attamyces lineages that appear lower in northern than in tropical populations; and (iv) long-distance gene flow of Attamyces across a dispersal barrier for leaf-cutter ants (ocean between mainland North America and Cuba). The latter suggests that Attamyces fungi may occasionally disperse independently of the ants, contrary to the traditional assumption that Attamyces fungi depend entirely on leaf-cutter queens for dispersal. Peripheral populations in Argentina or at mid-elevation sites in the Andes may reveal additional regional variants in ant– Attamyces coevolution. Studies of such populations are most likely to inform models of coextinctions of obligate mutualistic partners that are doubly stressed by habitat marginality and by environmental change.
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Sheley, Roger L., James S. Jacobs, and Michael F. Carpinelli. "Distribution, Biology, and Management of Diffuse Knapweed (Centaurea diffusa) and Spotted Knapweed (Centaurea maculosa)." Weed Technology 12, no. 2 (June 1998): 353–62. http://dx.doi.org/10.1017/s0890037x00043931.
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Diffuse knapweed, a biennial or short-lived perennial, and spotted knapweed, a perennial, are taprooted Eurasian weeds invading rangeland in the western United States and Canada. Knapweed (Centaureaspp.) invasion is associated with reductions in biodiversity, wildlife, and livestock forage, and increased erosion. Spotted knapweed grows to about 1 m and usually has purple flowers, whereas diffuse knapweed is slightly shorter, usually with white flowers. Persistent flower bracts on diffuse knapweed bear a rigid terminal spine about 8 mm long with four or five pairs of shorter lateral spines. Bracts on spotted knapweed have dark spotted tips. Knapweed management involves a combination of containing infestations and control efforts. Hand pulling in areas with small infestations can be effective for controlling spotted and diffuse knapweeds. Picloram applied at 0.28 kg ha−1provides control for about 3 yr. Effective long-term control of knapweeds requires periodic applications of picloram, which are only cost-effective on highly productive range sites with a residual grass understory. About 12 insect species have been released for knapweed biocontrol. Seed production has been reduced by 46% by insects feeding in the flower heads. Although insects have not reduced spotted knapweed densities, they may stress the weed and shift the competitive balance to associated species. Sheep grazing reduces the density of very young seedlings and may limit seedling recruitment into the population. In areas without a residual understory of desired plant species, revegetation of knapweed-infested rangeland is required. Components of any integrated weed management program are sustained effort, constant evaluation, and the adoption of improved strategies.
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Müller, H., D. Schroeder, and A. Gassmann. "AGAPETA ZOEGANA (L.) (LEPIDOPTERA: COCHYLIDAE), A SUITABLE PROSPECT FOR BIOLOGICAL CONTROL OF SPOTTED AND DIFFUSE KNAPWEED, CENTAUREA MACULOSA MONNET DE LA MARCK AND CENTAUREA DIFFUSA MONNET DE LA MARCK (COMPOSITAE) IN NORTH AMERICA." Canadian Entomologist 120, no. 2 (February 1988): 109–24. http://dx.doi.org/10.4039/ent120109-2.
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AbstractThe taxonomy, distribution, life history, and host plant relationships of the cochylid moth Agapeta zoegana (L.), an oligophagous, facultatively multivoltine root feeder, are discussed. The results of oviposition and larval feeding tests with 56 plant species in five families are presented and show that A. zoegana is restricted to a few closely related species of Centaurea. In Europe the moth is widely distributed and abundant in the majority of the root-feeding guilds of Centaurea maculosa Monnet de la Marck studied, with densities of 23.6 larvae per 100 roots in eastern Austria/northwestern Hungary and less than 8 larvae per 100 roots in central Hungary and the Alsace. The acceptance of target North American species (the tetraploid form of C. maculosa and the diploid Centaurea diffusa Monnet de la Marck), the damage caused, and the active searching ability rate A. zoegana as a potentially effective natural enemy of spotted and diffuse knapweed in North America. Agapeta zoegana will be especially promising as it predominantly attacks the rosette, which is, according to a recently developed population model for diffuse knapweed in Canada, the most sensitive stage determining equilibrium knapweed density. Agapeta zoegana is compatible with Pelochrista medullana Staudinger (Lepidoptera: Cochylidae), another knapweed root feeder recently introduced into North America, and will complement the seed-feeding species already established. The moth was approved for release in Canada and the USA and has been established in British Columbia since 1984 on C. diffusa.
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Lada, Elizabeth A., and Leo Blitz. "Two populations of diffuse molecular clouds." Astrophysical Journal 326 (March 1988): L69. http://dx.doi.org/10.1086/185125.
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Urbizu-González, Ana Lucía, Joel Flores, Edilia De la Rosa-Manzano, and Octelina Castillo-Ruíz. "Morphological differences of Turnera diffusa (Turneraceae) in two populations differing in rainfall at Northeastern Mexico." Botanical Sciences 97, no. 1 (March 13, 2019): 65. http://dx.doi.org/10.17129/botsci.2041.
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<p><strong>Background. </strong>Plant morphology is the expression of a set of characteristics in response to environmental conditions and therefore to the availability of resources.</p><p><strong>Questions. </strong>Are the populations of <em>Turnera diffusa</em> morphologically different due to climatic factors?</p><p><strong>Species studied.</strong> <em>Turnera diffusa</em>, known as “damiana”.</p><p><strong>Study site and dates. </strong>Jaumave and Güémez in Tamaulipas, Mexico; during October 2013 and April 2014.</p><p><strong>Methods. </strong>Abiotic characteristics of study sites and morphological traits of the plants were evaluated, as well as the exposure of the plants to light, and the flowering; 15 random transects of 100 m<sup>2</sup> each were made in each site. A multivariate analysis with linear discriminant functions was applied to determine possible differences between the two populations considering the morphological variables.</p><p><strong>Results. </strong>The population of <em>T. diffusa</em> of Güémez did present higher branch density and bigger leaves than those of Jaumave, which can be related to the greater precipitation that is received in that locality in comparison with Jaumave. <em>T. diffusa</em> plants with higher height were found under natural shade conditions and flowering is a condition that seems to be unrelated to the exposure. <strong></strong></p><p><strong>Conclusions. </strong>Populations of <em>Turnera diffusa</em> of Jaumave and Güémez were morphologically different.</p>
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Turner, Susan J., Colin C. Fleming, Brendan P. Moreland, and Trevor J. G. Martin. "Variation in hatch among pathotypes of the potato cyst nematodes, Globodera rostochiensis and G. pallida, in response to potato root diffusate from Solanum spp. I. Preliminary assessments to establish optimal testing conditions." Nematology 11, no. 5 (2009): 749–56. http://dx.doi.org/10.1163/156854109x411005.
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Abstract Potato cyst nematodes (PCN) hatch in response to the presence of root diffusate produced by host plants. Potato root diffusate (PRD) contains hatching factors that stimulate differential hatch between the two PCN species (Globodera rostochiensis and G. pallida) throughout the growing season. In order to clarify the role of PRD in wild potato clones resistant to PCN, a series of trials established optimal test conditions using a range of PCN populations on a representation of Solanum species (Solanum sanctae-rosae, S. sparsipilum, S. gourlayi, S. acaule, S. oplocense). Dilution tests showed that half strength PRD consistently stimulated highest levels of nematode hatch. PCN populations were treated with PRD collected weekly throughout the trials, mimicking the natural release of chemical stimulants from growing potato roots. Whilst the G. rostochiensis Ro1 population showed no variation in hatch, other populations displayed differences in hatch in the presence of the different Solanum PRD. This may reflect the different coevolutionary histories of nematodes and their Solanum hosts in South America.
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Bursztajn, S., S. A. Berman, J. L. McManaman, and M. L. Watson. "Insertion and internalization of acetylcholine receptors at clustered and diffuse domains on cultured myotubes." Journal of Cell Biology 101, no. 1 (July 1, 1985): 104–11. http://dx.doi.org/10.1083/jcb.101.1.104.
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Two populations of acetylcholine receptors (AChRs) are present in cultured myotubes. One forms large aggregates or clusters and the other has a much lower density of AChRs, which are diffusely distributed. Both clustered and diffuse AChRs are inserted and removed (internalized) from the sarcolemma. To determine the insertion and removal rates of AChRs in these two plasma membrane domains, we used a double label technique to distinguish and quantitate newly inserted and "old" AChRs. Application of our method revealed that the rate of AChR internalization is the same at the clustered and diffuse regions of the plasma membrane, whereas the rate of insertion is threefold greater at the clusters than elsewhere in the plasma membrane. Thus, the increase in AChR number at the clusters is not due to an increase in their half-life, but to an increase in their rate of insertion.
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Cohen, Shara B., and Anthony P. Weetman. "Activated interstitial and intraepithelial thyroid lymphocytes in autoimmune thyroid disease." Acta Endocrinologica 119, no. 2 (October 1988): 161–66. http://dx.doi.org/10.1530/acta.0.1190161.
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Abstract. This study has further characterised the thyroid lymphocytic infiltrate in Graves' disease and Hashimoto's thyroiditis. Two population of lymphocytes were identified. The interstitial population occurred as a diffuse and a focal infiltrate; most cells were CD3-positive (T cells) and in 4 of 6 glands CD8 (suppressor-cytotoxic)-positive T cells predominated. The intraepithelial population was CD3-negative, CD8-positive. Both populations also contained a few NK (Leu 11b positive cells) in some glands. Many of the lymphocytes in both populations stained with UCHL1 and RFT2 suggesting that these are primed and activated cells, borne out by staining for transferrin receptor expression. Although thyroid follicular cells were Ia-positive, macrophages and dentritic cells were found in all cases, so that a role for antigen-presentation by all three potential candidates in autoimmune thyroiditis is possible.
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Liu, Bing, and Rui-zhi Yang. "A hard spectrum diffuse γ-ray component associated with H II gas in the Galactic plane." Astronomy & Astrophysics 659 (March 2022): A101. http://dx.doi.org/10.1051/0004-6361/202039759.
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We analyzed 12-year Fermi Large Area Telescope γ-ray data in the inner Galaxy centered at (l = 30°, b = 0°) and (l = 330°, b = 0°). We found significant hardening of the spectrum of the diffuse γ-ray emission in these regions as previously reported. We further deduced that the diffuse γ rays can be divided into two components from the likelihood analysis. One component is associated with the total gas column density and reveals a soft spectrum, while the other is associated with the H II gas and presents a hard spectrum. Assuming the diffuse γ-ray emissions are mainly produced through the interaction between cosmic rays (CRs) and the ambient gas, these two components are produced by the CR populations with spectral indices of 2.8 (“soft”) and 2.3 (“hard”), respectively. We argue that the hard CR population may come from the vicinity of the CR accelerators. The soft CR population has a similar spectral shape and density as measured in the solar neighborhood, which implies a uniform CR “sea” with a similar density and spectral shape in the Galaxy.
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Iocco, F., G. Mangano, G. Miele, G. G. Raffelt, and P. D. Serpico. "Diffuse cosmic neutrino background from population III stars." Astroparticle Physics 23, no. 3 (April 2005): 303–12. http://dx.doi.org/10.1016/j.astropartphys.2005.01.004.
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Kis, A., M. Scholer, B. Klecker, H. Kucharek, E. A. Lucek, and H. Rème. "Scattering of field-aligned beam ions upstream of Earth's bow shock." Annales Geophysicae 25, no. 3 (March 29, 2007): 785–99. http://dx.doi.org/10.5194/angeo-25-785-2007.
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Abstract. Field-aligned beams are known to originate from the quasi-perpendicular side of the Earth's bow shock, while the diffuse ion population consists of accelerated ions at the quasi-parallel side of the bow shock. The two distinct ion populations show typical characteristics in their velocity space distributions. By using particle and magnetic field measurements from one Cluster spacecraft we present a case study when the two ion populations are observed simultaneously in the foreshock region during a high Mach number, high solar wind velocity event. We present the spatial-temporal evolution of the field-aligned beam ion distribution in front of the Earth's bow shock, focusing on the processes in the deep foreshock region, i.e. on the quasi-parallel side. Our analysis demonstrates that the scattering of field-aligned beam (FAB) ions combined with convection by the solar wind results in the presence of lower-energy, toroidal gyrating ions at positions deeper in the foreshock region which are magnetically connected to the quasi-parallel bow shock. The gyrating ions are superposed onto a higher energy diffuse ion population. It is suggested that the toroidal gyrating ion population observed deep in the foreshock region has its origins in the FAB and that its characteristics are correlated with its distance from the FAB, but is independent on distance to the bow shock along the magnetic field.
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HAVLIN, S., A. BUNDE, H. LARRALDE, Y. LEREAH, M. MEYER, P. TRUNFIO, and H. E. STANLEY. "SPREADING OF N DIFFUSING SPECIES WITH DEATH AND BIRTH FEATURES." Fractals 04, no. 02 (June 1996): 161–68. http://dx.doi.org/10.1142/s0218348x96000212.
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The number of distinct sites visited by a random walker after t steps is of great interest, as it provides a direct measure of the territory covered by a diffusing particle. We review the analytical solution to the problem of calculating SN(t), the mean number of distinct sites visited by N random walkers on a d-dimensional lattice, for d=1, 2, 3 in the limit of large N. There are three distinct time regimes for SN(t). A remarkable transition, for dimension ≥2, in the geometry of the set of visited sites is found. This set initially grows as a disk with a relatively smooth surface until it reaches a certain size, after which the surface becomes increasingly rough. We also review the results for a model for migration and spreading of populations and diseases. The model is based on N diffusing species, where each species has a probability α- of dying (or recovery from a disease) and a probability α+ to give birth (or to infect another species). It is found analytically that when α+ ≈ α- ≠ 0, after a crossover time t× ~ N/2α-, the territory covered by the population is localized around its center of mass while the center of mass diffuses regularly. When α+ > α-, the localization breaks down after a second crossover time and the species diffuse and spread around their center of mass. These results may explain the phenomena of migration and spreading of diseases and population appearing in nature.
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BERRY, WILLIAM D., and BRADY BAYBECK. "Using Geographic Information Systems to Study Interstate Competition." American Political Science Review 99, no. 4 (October 31, 2005): 505–19. http://dx.doi.org/10.1017/s0003055405051841.
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Scholars have proposed two distinct explanations for why policies diffuse across American states: (1) policymakers learn by observing the experiences of nearby states, and (2) states seek a competitive economic advantage over other states. The most common empirical approach for studying interstate influence is modeling an indicator of a state's policy choice as a function of its neighbors' policies, with each neighbor weighted equally. This can appropriately specify one form of learning model, but it does not adequately test for interstate competition: when a policy diffuses due to competition, states' responses to other states vary depending on the size and location of specific populations. We illustrate with two substantive applications how geographic information systems (GIS) can be used to test for interstate competition. We find that lottery adoptions diffuse due to competition—rather than to learning—but find no evidence of competition in state choices about welfare benefits. Our empirical approach can also be applied to competition among nations and local jurisdictions.
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Marrs, Robin A., René Sforza, and Ruth A. Hufbauer. "When invasion increases population genetic structure: a study with Centaurea diffusa." Biological Invasions 10, no. 4 (August 15, 2007): 561–72. http://dx.doi.org/10.1007/s10530-007-9153-6.
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Iwasaki, Risa L., Koji Ishiya, Hideaki Kanzawa-Kiriyama, Yosuke Kawai, Jun Gojobori, and Yoko Satta. "Evolutionary History of the Risk of SNPs for Diffuse-Type Gastric Cancer in the Japanese Population." Genes 11, no. 7 (July 10, 2020): 775. http://dx.doi.org/10.3390/genes11070775.
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A genome wide association study reported that the T allele of rs2294008 in a cancer-related gene, PSCA, is a risk allele for diffuse-type gastric cancer. This allele has the highest frequency (0.63) in Japanese in Tokyo (JPT) among 26 populations in the 1000 Genomes Project database. FST ≈ 0.26 at this single nucleotide polymorphism is one of the highest between JPT and the genetically close Han Chinese in Beijing (CHB). To understand the evolutionary history of the alleles in PSCA, we addressed: (i) whether the C non-risk allele at rs2294008 is under positive selection, and (ii) why the mainland Japanese population has a higher T allele frequency than other populations. We found that haplotypes harboring the C allele are composed of two subhaplotypes. We detected that positive selection on both subhaplotypes has occurred in the East Asian lineage. However, the selection on one of the subhaplotypes in JPT seems to have been relaxed or ceased after divergence from the continental population; this may have caused the elevation of T allele frequency. Based on simulations under the dual structure model (a specific demography for the Japanese) and phylogenetic analysis with ancient DNA, the T allele at rs2294008 might have had high frequency in the Jomon people (one of the ancestral populations of the modern Japanese); this may explain the high T allele frequency in the extant Japanese.
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Shokoohi, E., K. Nasira, E. Iqbal, S. Hussain, and P. W Mashela. "First report of Xiphinema diffusum from Pakistan." Helminthologia 58, no. 1 (February 10, 2021): 92–99. http://dx.doi.org/10.2478/helm-2021-0012.
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Summary The population of Xiphinema americanum species group was detected from the soil surronding the roots of peach (Prunus persica) during a survey of plant-parasitic nematodes in Gilgit-Baltistan, Pakistan. From the results of the morphological study, the species was identified as X. diffusum. Morphometrics of X. diffusum generally agree with those of the type species and the topotype specimens. Molecular analysis of 18S rDNA of X. diffusum from Pakistan indicated two nucleotide differences and 99 % similarity with the Chinese (AM086669) and the Australian (AM086685) population of X. diffusum. Phylogenetic analysis of 18S rDNA placed the Pakistanis population close to X. diffusum from China and Australia. This species is reported for the first time from Pakistan
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Stadnyk, A. W., A. D. Befus, and J. Gauldie. "Characterization of nonspecific esterase activity in macrophages and intestinal epithelium of the rat." Journal of Histochemistry & Cytochemistry 38, no. 1 (January 1990): 1–6. http://dx.doi.org/10.1177/38.1.1688447.
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We determined the histochemical characteristics of nonspecific esterase in different populations of rat macrophages. The cells included alveolar and peritoneal macrophages recovered by lavage and a mixed cell population obtained by collagenase digestion of the small intestine. The histochemically localized enzyme activity of alveolar and peritoneal macrophages was cytoplasmic, diffuse, and inhibited by sodium fluoride. Both populations were effectively stained using alpha-naphthyl acetate and alpha-naphthyl butyrate as the esterase substrate. When the intestinal cells were examined for activity, a greater percentage of cells showed positive nonspecific esterase than would be predicted by differential counts for macrophages on the basis of morphological criteria. We confirmed, using cell smears and tissue sections, that rat intestinal epithelial cells, a prominent component of the isolated cell population, possessed esterases that react similarly to macrophage esterases with histochemical procedures.
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Damiani, F., L. Prisinzano, I. Pillitteri, G. Micela, and S. Sciortino. "Stellar population of Sco OB2 revealed by Gaia DR2 data." Astronomy & Astrophysics 623 (March 2019): A112. http://dx.doi.org/10.1051/0004-6361/201833994.
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Context. The Sco OB2 association is the nearest OB association, extending over approximately 2000 square degrees on the sky. Only its brightest and most massive members are already known (from HIPPARCOS) across its entire size, while studies of its lower mass population refer only to small portions of its extent. Aims. In this work we exploit the capabilities of Gaia DR2 measurements to search for Sco OB2 members across its entire size and down to the lowest stellar masses. Methods. We used both Gaia astrometric (proper motions and parallaxes) and photometric measurements (integrated photometry and colors) to select association members, using minimal assumptions derived mostly from the HIPPARCOS studies. Gaia resolves small details in both the kinematics of individual Sco OB2 subgroups and their distribution with distance from the Sun. We developed methods to explore the 3D kinematics of a stellar population covering large sky areas. Results. We find nearly 11 000 pre-main-sequence (PMS) members of Sco OB2 (with less than 3% field-star contamination), plus ∼3600 main-sequence (MS) candidate members with a larger (10–30%) field-star contamination. A higher confidence subsample of ∼9200 PMS (and ∼1340 MS) members is also selected (<1% contamination for the PMS), however this group is affected by larger (∼15%) incompleteness. We separately classify stars in compact and diffuse populations. Most members belong to one of several kinematically distinct diffuse populations, whose ensemble clearly outlines the shape of the entire association. Upper Sco is the densest region of Sco OB2. It is characterized by a complex spatial and kinematical structure and has no global pattern of motion. Other dense subclusters are found in Lower Centaurus-Crux and in Upper Centaurus-Lupus; the richest example of the latter, which has been recently identified, is coincident with the group near V1062 Sco. Most of the clustered stars appear to be younger than the diffuse PMS population, suggesting star formation in small groups that rapidly disperse and are diluted, reaching space densities lower than field stars while keeping memory of their original kinematics. We also find that the open cluster IC 2602 has a similar dynamics to Sco OB2, and its PMS members are currently evaporating and forming a diffuse (size ∼10°) halo around its double-peaked core.
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Abdulwahid, Hiba Mohammed, Lubna Ali Hussien, and Areege Mustafa Kamal. "The Value of Ultrasound Elastography in Diffuse Thyroid Disease among a Sample of Iraqi Population." Open Access Macedonian Journal of Medical Sciences 9, B (November 21, 2021): 1647–53. http://dx.doi.org/10.3889/oamjms.2021.6060.
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Abstract
Background: Early detection of many thyroid disorders is essential in the management. Ultrasound elastography is beneficial in the assessment of diffuse thyroid diseases.
Aim of study: To assess the role of ultrasound strain elastography in the diagnosis of diffuse non nodular thyroid disease in comparison to healthy controls and in the characterization and differentiation of the types of diffuse thyroid diseases.
Patients and methods: It is a prospective analytic study performed in the Radiology Department of Oncology Teaching Hospital/Medical city Complex in Baghdad during the period from 1st of December 2019 to 30th of June, 2020 on convenient sample of 25 patients with diffuse thyroid disease, in addition to a sample of 25 healthy control persons. The diagnosis of diffuse thyroid diseases was made by combination of clinical symptoms, laboratory investigations and thyroid ultrasound.
Results: The mean elastography strain ratio (1.36) of patients with diffuse thyroid disease was significantly higher than (0.82) mean of elastography strain ratio for healthy control persons (p<0.001). The acceptable cutoff elastography strain ratio in the diagnosis of diffuse thyroid disease was 0.89 with validity results (80% sensitivity, 70% specificity and 75% accuracy). The mean elastography strain ratio for patients with Hashimotos thyroiditis was significantly higher than the strain ratio of patients with Graves disease (p=0.002).
Conclusions: The ultrasound elastography is useful in the assessment and characterization of diffuse thyroid disease. The ultrasound elastography strain ratio value is helpful in differentiation between different diffuse thyroid diseases especially between Hashimotos thyroiditis and Graves's disease
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Powell, Robert D. "The Role of Spatial Pattern in the Population Biology of Centaurea Diffusa." Journal of Ecology 78, no. 2 (June 1990): 374. http://dx.doi.org/10.2307/2261118.
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Kutyrev, IA, and VA Mordvinov. "Population genetic structure of diphyllobothriid tapeworms (Cestoda: Diphyllobothriidea) parasitising fish in the Baikal Rift Zone." Diseases of Aquatic Organisms 148 (March 17, 2022): 113–25. http://dx.doi.org/10.3354/dao03646.
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Tapeworms of the genus Dibothriocephalus are widely distributed throughout the world, and some are agents of human diphyllobothriasis, one of the most important fish-borne zoonoses caused by a cestode parasite. Until now, the population genetic structure of diphyllobothriid tapeworms in the Baikal Rift Zone (BRZ) has remained unexplored. The major aim of this study was to analyse the population genetic structure of D. dendriticus and D. ditremus parasitising fish in the BRZ based on internal transcribed spacer 1 (ITS1) and mitochondrial gene cytochrome oxidase subunit I (cox1) sequences. We found that both species had complex population genetic structures. Each species formed 2 clades (D. dendriticus: Clade 1 & 2; D. ditremus Clade A & B) that differed in genetic diversity. D. dendriticus haplotypes in Clade 1 formed a star-like sub-network with a main haplotype, whereas the haplotypes in Clade 2 formed a diffuse network. We assumed that the complex population genetic structure of D. dendriticus was a consequence of populations evolving under different palaeoecological conditions during the Last Glacial Maximum. In contrast to D. dendriticus, both clades in the D. ditremus samples formed a diffuse network. Our findings revealed hypothetical pathways in the formation of the population genetic structure of diphyllobothriids in the BRZ. On one hand, isolation by distance played an important role; on the other hand, lake recolonisation from refugia and a genetic bottleneck after the end of the Last Glacial Maximum had a possible influence.
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Kassin, Susan A., Jay A. Frogel, and Richard W. Pogge. "Stellar Populations in the Antennae (NGC 4038/9): Exploring a Galaxy Merger Pixel By Pixel." Symposium - International Astronomical Union 207 (2002): 483–86. http://dx.doi.org/10.1017/s0074180900224285.
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We use B, V, and K-band images of the Antennae in a detailed analysis of its stellar populations. Significant large and small-scale spatial variations in the stellar populations are found by examining images pixel by pixel. Flux ratio, or linear color, diagrams allow us to find the stellar populations present in each pixel using a novel technique. This is done through a comparison of the colors of pixels to those of well-studied populations such as elliptical/S0 galaxies, Magellanic Cloud clusters, and Sc galactic nuclei, in addition to stellar population models. This technique allows us to study not only star clusters, but also the diffuse light present in the Antennae. From these flux-ratio diagrams, a luminosity-weighted de-reddened age image of the Antennae is constructed. Our analysis technique complements and extends results based on Hubble Space Telescope images.
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Martig, Noemi, and Julian Bernauer. "The Halo Effect: Perceptions of Diffuse Threat and SVP Vote Share." World Political Science 14, no. 1 (April 25, 2018): 27–54. http://dx.doi.org/10.1515/wps-2018-0002.
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Abstract The voter strength of right-wing populist parties is regularly attributed either to a feeling of threat from a high proportion of local foreigners or to the lack of opportunities for contact between the majority and the minority. This contribution is theoretically based on a synthesis of these perspectives, known as the Halo effect. Accordingly, it is not so much the local size of the local population, which is perceived as foreign, but rather its relative proportion in the surrounding countryside, which leads to a diffuse feeling of threat. The electoral success of the Swiss People’s Party (SVP) at the level of the Swiss municipalities serves as a basis for the empirical investigation, which is conducted alternatively with the proportions of the foreign and Muslim population. For both groups, spatial multilevel regression models provide indications of a coexistence of direct negative effects of minority populations on the share of the SVP (in the sense of the contact hypothesis) and of Halo effects, with the direct effects appearing to be somewhat more pronounced. Socio-structural factors can reduce these correlations (high unemployment neutralises the negative effect of the proportion of foreigners) or intensify these correlations (a higher income level accentuates the Halo effect for Muslims).
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Van Nest, Jordan D., F. Munshi, A. C. Wright, M. Tremmel, A. M. Brooks, D. Nagai, and T. Quinn. "What’s in a Name? Quantifying the Interplay between the Definition, Orientation, and Shape of Ultra-diffuse Galaxies Using the Romulus Simulations." Astrophysical Journal 926, no. 1 (February 1, 2022): 92. http://dx.doi.org/10.3847/1538-4357/ac43b7.
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Abstract We explore populations of ultra-diffuse galaxies (UDGs) in isolated, satellite, and cluster environments using the Romulus25 and Romulus C simulations, including how the populations vary with UDG definition and viewing orientation. Using a fiducial definition of UDGs, we find that isolated UDGs have notably larger semimajor (b/a) and smaller semiminor (c/a) axis ratios than their non-UDG counterparts, i.e., they are more oblate, or diskier. This is in line with previous results that adopted the same UDG definition and showed that isolated UDGs form via early, high-spin mergers. However, the choice of UDG definition can drastically affect what subsets of a dwarf population are classified as UDGs, changing the number of UDGs by up to ∼45% of the dwarf population. We also find that a galaxy’s classification as a UDG is dependent on its viewing orientation, and this dependence decreases as environmental density increases. Overall, we conclude that some definitions for UDGs used in the literature manage to isolate a specific formation mechanism for isolated dwarfs, while less restrictive definitions erase a link to the formation mechanism. Thus, how we define UDG populations must be considered if we want to understand the formation and evolution of UDGs.
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Omedo, Irene, Polycarp Mogeni, Teun Bousema, Kirk Rockett, Alfred Amambua-Ngwa, Isabella Oyier, Jennifer C. Stevenson, et al. "Micro-epidemiological structuring of Plasmodium falciparum parasite populations in regions with varying transmission intensities in Africa." Wellcome Open Research 2 (February 14, 2017): 10. http://dx.doi.org/10.12688/wellcomeopenres.10784.1.
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Background: The first models of malaria transmission assumed a completely mixed and homogeneous population of parasites. Recent models include spatial heterogeneity and variably mixed populations. However, there are few empiric estimates of parasite mixing with which to parametize such models. Methods: Here we genotype 276 single nucleotide polymorphisms (SNPs) in 5199 P. falciparum isolates from two Kenyan sites and one Gambian site to determine the spatio-temporal extent of parasite mixing, and use Principal Component Analysis (PCA) and linear regression to examine the relationship between genetic relatedness and relatedness in space and time for parasite pairs. Results: We show that there are no discrete geographically restricted parasite sub-populations, but instead we see a diffuse spatio-temporal structure to parasite genotypes. Genetic relatedness of sample pairs is predicted by relatedness in space and time. Conclusions: Our findings suggest that targeted malaria control will benefit the surrounding community, but unfortunately also that emerging drug resistance will spread rapidly through the population.
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Cai, Hong, Anna Ghazaryan, and Vahagn Manukian. "Fisher-KPP dynamics in diffusive Rosenzweig–MacArthur and Holling–Tanner models." Mathematical Modelling of Natural Phenomena 14, no. 4 (2019): 404. http://dx.doi.org/10.1051/mmnp/2019017.
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We prove the existence of traveling fronts in diffusive Rosenzweig–MacArthur and Holling–Tanner population models and investigate their relation with fronts in a scalar Fisher-KPP equation. More precisely, we prove the existence of fronts in a Rosenzweig–MacArthur predator-prey model in two situations: when the prey diffuses at the rate much smaller than that of the predator and when both the predator and the prey diffuse very slowly. Both situations are captured as singular perturbations of the associated limiting systems. In the first situation we demonstrate clear relations of the fronts with the fronts in a scalar Fisher-KPP equation. Indeed, we show that the underlying dynamical system in a singular limit is reduced to a scalar Fisher-KPP equation and the fronts supported by the full system are small perturbations of the Fisher-KPP fronts. We obtain a similar result for a diffusive Holling–Tanner population model. In the second situation for the Rosenzweig–MacArthur model we prove the existence of the fronts but without observing a direct relation with Fisher-KPP equation. The analysis suggests that, in a variety of reaction–diffusion systems that rise in population modeling, parameter regimes may be found when the dynamics of the system is inherited from the scalar Fisher-KPP equation.
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Paixão, Gustavo, Alexandra Esteves, Rita Payan-Carreira, and Nuno Carolino. "Demographic structure and genetic diversity of the endangered Bísaro pig: Evolution and current status." Czech Journal of Animal Science 63, No. 11 (November 7, 2018): 452–61. http://dx.doi.org/10.17221/113/2018-cjas.
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Bísaro pig, a local endangered swine breed, has gained popularity in the recent years. A complete pedigree was used to evaluate the population structure and investigate the current breed’s genetic variability in two reference populations (AlivePop and AliveBpop). Since the breed’s foundation, the number of registered animals, producers, and farrowing records has increased. The mean progeny size for sires was 116.17 ± 210.81, and 3.24% of the breeding boars originated 26.54% of all registered births showing a marked unbalanced use of certain sires. The mean calculated equivalent generations was 4.54, and 98.1% of all the animals had known parents, indicating a good degree of pedigree completion and depth. Approximately half of the individuals were inbred, with average inbreeding values of 10.41, 9.02, and 8.58% for the whole and reference populations, respectively. Considering both reference populations, a low effective founder/ancestor ratio was obtained (1.12), showing a well-balanced founder/ancestor contribution, and subsequent genetic transfer. However, the effective founder/founder ratio was particularly low (0.06 and 0.12) compared with other native breeds. The founder genome/effective founder ratios were 0.37 and 0.41 for AlivePop and AliveBpop. Contrarily to the whole population, the random genetic drift weighted significantly more than the drift due to unequal founder contribution in the reference populations. The effective population size based on the increase in coancestry ranged from 62.39 and 54.66, and 16.74 and 24.84 based on the increase of individual inbreeding, for the whole and reference populations. The genetic conservation index steadily grew over the years with a mean value of 6.53 for the whole pedigree. Genetic variability losses and diffuse structuring might have occurred in the Bísaro population. Notwithstanding, the recent genetic variability indicators seem positive, yet supported by an open herdbook policy. These characteristics must be taken into account to define future mating policies and selection programs.
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Strong, A. W. "Source population synthesis and the Galactic diffuse gamma-ray emission." Astrophysics and Space Science 309, no. 1-4 (April 18, 2007): 35–41. http://dx.doi.org/10.1007/s10509-007-9480-1.
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Petrovic, Jovana, Tijana Prodanovic, and Milos Kovacevic. "Understanding the diffuse gamma ray emission of the milky way - from supernova remnants to dark matter." Zbornik Matice srpske za prirodne nauke, no. 137 (2019): 17–22. http://dx.doi.org/10.2298/zmspn1937017p.
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Diffuse gamma ray emission from the Galactic center at 2-3 GeV, as well as the 12 TeV gamma ray excess in the Galactic disk, remain open for debate and represent the missing puzzles in the complete picture of the high-energy Milky Way sky. Our papers emphasize the importance of understanding all of the populations that contribute to the diffuse gamma background in order to discriminate between the astrophysical sources such as supernova remnants and pulsars, and something that is expected to be seen in gamma rays and is much more exotic - dark matter. We analyze two separate data sets that have been measured in different energy ranges from the ?Fermi-LAT? and ?Milagro? telescopes, using these as a powerful tool to limit and test our analytical source population models. We model supernova remnants and pulsars, estimating the number of still undetected ones that contribute to the diffuse background, trying to explain both the Galactic center and the 12 TeV excess. Furthermore, we aim to predict the number of soon to be detected sources with new telescopes, such as the ?HAWC?.
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Drake, Steven, and Joshua Cowen. "Deurbanization and the Struggle to Sustain a Black Teaching Corps: Evidence From Michigan." Educational Researcher 51, no. 1 (October 13, 2021): 27–39. http://dx.doi.org/10.3102/0013189x211051312.
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From 2005 to 2015, the number of Black teachers in Michigan dropped by 48%, substantially exceeding declines in the corresponding K–12 Black student population. These teacher losses are an acute phenomenon within a broader national context of deurbanization of K–12 student populations away from those districts with the largest and most established faculties of color. Districts receiving large numbers of incoming Black students hired few Black teachers over the period, leading to marked declines in Black student exposure to Black educators, and Black employment gains since 2016 have generally been in areas where Black teachers were already employed. We discuss the historical conditions under which Michigan’s Black faculties were established and multiple forward-looking challenges to building and sustaining Black faculties in geographically diffuse populations.
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Amaker, Barbara H., Nitya R. Ghatak, Sean A. Jebraili, Andrea Ferreira-Gonzalez, and Michael J. Kornstein. "Primary T-Cell–Rich B-Cell Lymphoma Masquerading as a Meningioma." Archives of Pathology & Laboratory Medicine 124, no. 11 (November 1, 2000): 1700–1703. http://dx.doi.org/10.5858/2000-124-1700-ptcrbc.
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Abstract Primary dural lymphoma is rare, and few of the small number of cases reported to date have been classified using immunohistochemical techniques. To our knowledge, we report the first case of T-cell–rich B-cell lymphoma (diffuse mixed small cell and large cell) presenting as a solitary intracranial dural mass. Cytologic and frozen sections prepared during intraoperative consultation revealed a polymorphic population of lymphocytes suspicious for an inflammatory process. Permanent sections of the dura showed a diffusely infiltrating mass composed of mature lymphocytes peppered with large atypical lymphocytes. Immunohistochemical stains identified the small lymphocytes as T cells (CD3 and CD43) and the large atypical lymphocytes as B cells (CD20). Evidence of rearranged immunoglobulin heavy-chain genes demonstrated B-cell monoclonality. Differentiating between inflammatory and neoplastic lymphocytic masses of the dura obviously has important therapeutic and prognostic significance and may require immunohistochemical and molecular techniques.
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Espinosa-Ponce, C., S. F. Sánchez, C. Morisset, J. K. Barrera-Ballesteros, L. Galbany, R. García-Benito, E. A. D. Lacerda, and D. Mast. "H ii regions in the CALIFA survey: I. catalogue presentation." Monthly Notices of the Royal Astronomical Society 494, no. 2 (March 20, 2020): 1622–46. http://dx.doi.org/10.1093/mnras/staa782.
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ABSTRACT We present a new catalogue of H ii regions based on the integral field spectroscopy (IFS) data of the extended CALIFA and PISCO samples. The selection of H ii regions was based on two assumptions: a clumpy structure with high contrast of H α emission and an underlying stellar population comprising young stars. The catalogue provides the spectroscopic information of 26 408 individual regions corresponding to 924 galaxies, including the flux intensities and equivalent widths of 51 emission lines covering the wavelength range between 3745 and 7200 Å. To our knowledge, this is the largest catalogue of spectroscopic properties of H ii regions. We explore a new approach to decontaminate the emission lines from diffuse ionized gas contribution. This diffuse gas correction was estimated to correct every emission line within the considered spectral range. With the catalogue of H ii regions corrected, new demarcation lines are proposed for the classical diagnostic diagrams. Finally, we study the properties of the underlying stellar populations of the H ii regions. It was found that there is a direct relationship between the ionization conditions on the nebulae and the properties of stellar populations besides the physicals condition on the ionized regions.
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Nersesian, Angelos, Sébastien Viaene, Ilse De Looze, Maarten Baes, Emmanuel M. Xilouris, Matthew W. L. Smith, Simone Bianchi, et al. "High-resolution, 3D radiative transfer modelling." Astronomy & Astrophysics 643 (November 2020): A90. http://dx.doi.org/10.1051/0004-6361/202038939.
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Context. Investigating the dust heating mechanisms in galaxies provides a deeper understanding of how the internal energy balance drives their evolution. Over the last decade radiative transfer simulations based on the Monte Carlo method have emphasised the role of the various stellar populations heating the diffuse dust. Beyond the expected heating through ongoing star formation, older stellar populations (≥8 Gyr) and even active galactic nuclei can both contribute energy to the infrared emission of diffuse dust. Aims. In this particular study we examine how the radiation of an external heating source, such as the less massive galaxy NGC 5195 in the M 51 interacting system, could affect the heating of the diffuse dust of its parent galaxy NGC 5194, and vice versa. Our goal is to quantify the exchange of energy between the two galaxies by mapping the 3D distribution of their radiation field. Methods. We used SKIRT, a state-of-the-art 3D Monte Carlo radiative transfer code, to construct the 3D model of the radiation field of M 51, following the methodology defined in the DustPedia framework. In the interest of modelling, the assumed centre-to-centre distance separation between the two galaxies is ∼10 kpc. Results. Our model is able to reproduce the global spectral energy distribution of the system, and it matches the resolved optical and infrared images fairly well. In total, 40.7% of the intrinsic stellar radiation of the combined system is absorbed by dust. Furthermore, we quantify the contribution of the various dust heating sources in the system, and find that the young stellar population of NGC 5194 is the predominant dust-heating agent, with a global heating fraction of 71.2%. Another 23% is provided by the older stellar population of the same galaxy, while the remaining 5.8% has its origin in NGC 5195. Locally, we find that the regions of NGC 5194 closer to NGC 5195 are significantly affected by the radiation field of the latter, with the absorbed energy fraction rising up to 38%. The contribution of NGC 5195 remains under the percentage level in the outskirts of the disc of NGC 5194. This is the first time that the heating of the diffuse dust by a companion galaxy is quantified in a nearby interacting system.
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Borovkov, L. P., B. V. Kozelov, L. S. Yevlashin, and S. A. Chernouss. "Variations of auroral hydrogen emission near substorm onset." Annales Geophysicae 23, no. 5 (July 27, 2005): 1623–35. http://dx.doi.org/10.5194/angeo-23-1623-2005.
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Abstract. The results of coordinated optical ground-based observations of the auroral substorm on 26 March 2004 in the Kola Peninsula are described. Imaging spectrograph data with high spectral and temporal resolution recorded the Doppler profile of the Hα hydrogen emission; this allows us to estimate the average energy of precipitating protons and the emission intensity of the hydrogen Balmer line. Two different populations of precipitating protons were observed during an auroral substorm. The first of these is associated with a diffuse hydrogen emission that is usually observed in the evening sector of the auroral oval and located equatorward of the discrete electron arcs associated with substorm onset. The average energy of the protons during this precipitation was ~20–35 keV, and the energy flux was ~3x10–4Joule/m2s. The second proton population was observed 1–2min after the breakup during 4–5min of the expansion phase of substorm into the zone of bright, discrete auroral structures (N-S arcs). The average energy of the protons in this population was ~60 keV, and the energy flux was ~2.2x10–3Joule/m2s. The observed spatial structure of hydrogen emission is additional evidence of the higher energy of precipitated protons in the second population, relative to the protons in the diffuse aurora. We believe that the most probable mechanism of precipitation of the second population protons was pitch-angle scattering of particles due to non-adiabatic motion in the region of local dipolarization near the equatorial plane.Keywords. Auroral ionosphere; Particle precipitation; Storms and substorms
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Maziarz, Richard T., Jie Zhang, Hongbo Yang, Xinglei Chai, Chengbo Yuan, Elisabeth Schwarz, Mihael Jakovac, et al. "Indirect comparison of tisagenlecleucel and historical treatments for relapsed/refractory diffuse large B-cell lymphoma." Blood Advances 6, no. 8 (April 19, 2022): 2536–47. http://dx.doi.org/10.1182/bloodadvances.2021006280.
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Abstract No head-to-head trials have compared the efficacy of tisagenlecleucel vs historical treatments for adults with relapsed or refractory diffuse large B-cell lymphoma (r/r DLBCL). This study indirectly compared the overall survival (OS) and overall response rate (ORR) associated with tisagenlecleucel, using data from the JULIET study (Study of Efficacy and Safety of CTL019 in Adult DLBCL Patients; #NCT02445248), vs historical treatments assessed in the CORAL (Collaborative Trial in Relapsed Aggressive Lymphoma) study follow-up population. To assess treatment effects in the treated (full analysis set [FAS]) and enrolled (intention-to-treat [ITT]) study populations, the JULIET FAS vs the CORAL follow-up FAS and JULIET ITT vs CORAL follow-up ITT populations were separately compared. Propensity score weighting using standardized mortality ratio weight (SMRW) and fine stratification weight (FSW) was used to compare OS and ORR, adjusting for baseline confounders. The results indicated that tisagenlecleucel was associated with a lower hazard of death among the FAS (adjusted hazard ratio [95% confidence interval], both FSW and SMRW, 0.44 [0.32, 0.59]) and ITT populations (FSW, 0.60 [0.44, 0.77]; SMRW, 0.57 [0.44, 0.73]; all, P < .001). Median OS was 12.48 months (JULIET) vs 4.34 to 4.40 months (CORAL) for the FAS, and 8.25 (JULIET) months vs 4.04 to 4.86 (CORAL) months for the ITT populations. Tisagenlecleucel was associated with a significantly higher ORR compared with historical treatments among the FAS (adjusted response rate difference [95% confidence interval], both FSW and SMRW, 36% [22%, 0.48%]; P < .001) and among the ITT populations after SMRW adjustment (11% [0%, 22%]; P = .043). This analysis supports that improved response and OS are achieved in patients with r/r DLBCL treated with tisagenlecleucel compared with those treated with alternative historical treatments.
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Gonçalves, Elaine Cristine Piffer, Antonio Orlando Di Mauro, and Maria Aparecida Pessôa da Cruz Centurion. "Genetics of resistance to powdery mildew (Microsphaera diffusa) in Brazilian soybean populations." Genetics and Molecular Biology 25, no. 3 (2002): 339–42. http://dx.doi.org/10.1590/s1415-47572002000300015.
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Koga, Tomoyuki, Shunichiro Miki, Kasey R. Skinner, Sriram Venneti, Denise Malicki, Robert Wechsler-Reya, Robert Gruener, et al. "TMOD-07. HUMAN DIFFUSE MIDLINE GLIOMA AVATARS AS A PLATFORM TO SEARCH FOR NOVEL THERAPEUTIC TARGETS." Neuro-Oncology 22, Supplement_2 (November 2020): ii229. http://dx.doi.org/10.1093/neuonc/noaa215.958.
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Abstract Diffuse midline glioma is the leading cause of brain tumor death among the pediatric population. Drugs that show notable promise in preclinical models inevitably fail to demonstrate efficacy in clinical trials, likely due to the inadequacy of preclinical models. We have recently proposed glioblastoma models derived from human induced pluripotent stem cells (hiPSCs) genetically engineered with different combinations of glioblastoma-associated genetic alterations as a platform to search for therapeutic targets. These glioblastoma avatars authentically recapitulated the different pathobiology of glioblastoma subtypes, depending on what genetic alterations to be introduced. To investigate the biology and to develop novel therapeutics for diffuse midline glioma with H3K27M mutation, we have established a novel model by introducing H3.3 K27M mutation together with one of the most common concurrent genetic alterations, TP53 R248Q mutation, into hiPSCs through CRISPR/Cas9 genome engineering. Orthotopic engraftment of the neural progenitor cells derived from these edited hiPSCs formed diffusely invasive brainstem tumors with histological features of the diffuse midline glioma. These tumor avatars presented a global reduction in H3K27me3 accompanied by the expression of H3K27M. Transcriptome analyses of these models revealed that these avatars with H3K27M cluster apart from the pediatric glioma samples without this particular mutation, and that they present signatures of oligodendroglial progenitor differentiation as discovered in patient samples with this mutation. Using these models faithfully recapitulating histology and pathobiology of the patient tumors, we have performed drug screening and confirmed that their sensitivity to known drugs, including an EZH2 inhibitor and histone deacetylase inhibitors. On these faithful human avatars of diffuse midline glioma with H3K27M, we have applied bioinformatics algorithms of drug sensitivity prediction aiming at developing novel therapeutics for this devastating pediatric glioma.
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NNEJI, Emmanuel Tochukwu, Robert O. UDDIN II, and Abdulrasak K. MUSA. "Effects of Boerhavia diffusa L. nom. cons. and Chromolaena odorata (L.) R. M. King & H. Rob. extracts on some field insect pests of okra (Aabelmoschus esculentus (L.) Moench)." Acta agriculturae Slovenica 115, no. 1 (March 5, 2020): 133. http://dx.doi.org/10.14720/aas.2020.115.1.1299.
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<p>A field study was carried out to assess the efficacy of some botanicals in the control of field insect pests in two varieties of okra. Dry leaf extract of <em>Chromolaena odorata</em> (Siam weed) and fresh and dry root extracts of <em>Boerhavia diffusa</em> served as treatments which were compared with Lambda-cyhalothrin and a control. The experiment was fitted into a randomized complete block design with three replications. Data collected were subjected to Spearman’s correlation analysis and a two-way analysis of variance and significant different means were separated using Fishers Least Significant Difference (LSD) test at 5 % level of probability. The results revealed that treated plants generally performed better than the untreated plants as they were taller, had more leaves, branches, wider stem girths and gave higher fruit yield. Fresh root extract of <em>B. diffusa</em> performed better in most parameters measured. A significant positive correlation was observed between insect pest populations, and between growth and yield parameters, while there was a significant negative correlation between overall yield and insect pest population. NHAe 47-4 okra variety performed better than F1-Lucky variety. Fresh root extract of <em>B. diffusa</em> is recommended for management of <em>B. tabaci </em>(Genadius, 1889)<em> </em>and <em>Amrasca biguttula </em>Ishida, 1912<em> </em>in okra.</p>
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Amkhadova, Malkan A., G. G. Ashurov, A. A. Ismoilov, S. M. Karimov, and D. E. Dzhuraev. "INFLUENCE OF DISADVANTAGE PHYSICIAN-SOCIAL FACTOR ON CONDITION OF PARODONTOLOGY STATUS OF THE ADULT POPULATION WITH TEETH-MAXILLA ANOMALY." Russian Journal of Dentistry 23, no. 3-4 (August 15, 2019): 140–43. http://dx.doi.org/10.18821/1728-2802-2019-23-3-4-140-143.
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Results of the study of the influence disadvantage physician-social factor of the risk on condition of the structured parodontal tissue units’ beside persons with teeth-maxilla anomaly presented in article. From the gross amount of examined patient (n=578) beside 54.2% of them diagnosed chronic localized gingivitis, beside 6.9% - chronic diffuse gingivitis, beside 27.7% and 8.8% - accordingly chronic localized and diffuse parodontitis and beside 2.4% - chronic diffuse parodontosis. Formation, smoking and bruxism possible consider as factors of the risk of the development diffuse forms of the gingivitis and parodontitis, but beside patient with parodontosis more often revealed somatic pathology.
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McLoud, TC, BO Woods, CB Carrington, GR Epler, and EA Gaensler. "Diffuse pleural thickening in an asbestos-exposed population: prevalence and causes." American Journal of Roentgenology 144, no. 1 (January 1985): 9–18. http://dx.doi.org/10.2214/ajr.144.1.9.
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Uehara, Masashi, Jun Takahashi, Shota Ikegami, Ryosuke Tokida, Hikaru Nishimura, Noriko Sakai, and Hiroyuki Kato. "Prevalence of Diffuse Idiopathic Skeletal Hyperostosis in the General Elderly Population." Clinical Spine Surgery 33, no. 3 (April 2020): 123–27. http://dx.doi.org/10.1097/bsd.0000000000000919.
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Galkina, N. V., E. A. Troshina, and N. V. Mazurina. "The Genetic Predisposition for Diffuse Euthyroid Goiter Development in Moscow Population." Clinical and experimental thyroidology 4, no. 3 (September 15, 2008): 36. http://dx.doi.org/10.14341/ket20084336-43.
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Robitaille, Norbert, and Robert R. Bourbeau. "Estimation de la population corrigée pour le sous-dénombrement par sexe et par âge, Québec, 1971 et 1976." Articles 9, no. 1 (January 6, 2009): 87–104. http://dx.doi.org/10.7202/600810ar.
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RÉSUMÉ Il est admis que les résultats des recensements canadiens sont entachés d’un certain sous-dénombrement, plus ou moins important, suivant les années et les sous-groupes. Pour le Québec, Statistique Canada diffuse des estimations de ce sous-dénombrement pour certains grands groupes d’âge en 1976 et uniquement pour l’ensemble de la population en 1971. De ces estimations, les auteurs ont dérivé, pour le Québec, moyennant certaines hypothèses, des taux de sous-dénombrement par groupe quinquennal d’âge et par sexe. Ceux-ci, appliqués à la population recensée ont fourni des populations corrigées de l’erreur desous-dénombrement. Ainsi, les 129 298 personnes que Statistique Canada estime avoir été omises en 1971 (taux de 2,10%) de même que les 189 655 personnes que l’on estime être dans la même situation en 1976 (taux de 2,95%) sont réparties suivant le groupe d’âge et le sexe.
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Salles, Gilles, Budhaditya Goswami, Vincenzo Bagnardi, Debarshi Dey, Mark Winderlich, Sumeet Ambarkhane, Dan Huang, and Grzegorz S. Nowakowski. "Estimation of Long-Term Survival with Tafasitamab + Lenalidomide in Relapsed/Refractory Diffuse Large B-Cell Lymphoma." Blood 136, Supplement 1 (November 5, 2020): 9–10. http://dx.doi.org/10.1182/blood-2020-140398.
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Background L-MIND (NCT02399085) is an ongoing, open-label, single-arm, Phase II study of tafasitamab + lenalidomide (LEN) in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who are ineligible for autologous stem cell transplant. Progression-free survival (PFS) estimates the treatment effect of the study drug only, while overall survival (OS) also includes effects of potential subsequent cancer treatments or palliative care. Given that not all OS and PFS events have occurred after a long follow-up duration, traditional survival analyses may underestimate survival benefit for tafasitamab + LEN by assuming the same mortality rate for the whole population. We used mixture cure models to estimate the proportion of long-term survivors (LTS) and survival benefit associated with tafasitamab + LEN treatment. Methods In the L-MIND study (data cut-off: Nov 30, 2019), 80/81 enrolled patients with R/R DLBCL received tafasitamab + LEN, with a median and maximum follow-up duration of 31.8 months (95% CI: 27.2-35.9) and 43.5 months, respectively. The Kaplan-Meier (KM) plots of PFS and OS were observed to plateau after 30 months, with the majority of events reported up to that time-point and very few events beyond this time-point. Patients without a PFS event or patients who did not decease after the observed plateau exhibit a high survival benefit from tafasitamab + LEN treatment and are considered LTS. Thus, the patient population can be considered to consist of two sub-populations - LTS and non-LTS. A "mixture cure model" was fitted on the PFS and OS data to estimate the proportion of LTS and associated mean survival for the two sub-populations (Lambert PC, et al. 2007). To incorporate background mortality (Bansal, et al. 2019), age- and sex-specific US mortality rates (US CDC 2017) were factored in for the entire study population (enrolled in Europe and US). The weighted average of the mean survival for the two sub-populations provided an estimate of the mean survival for the whole population. For comparative purposes, standard parametric models without considering an LTS proportion were fitted on PFS and OS data additionally. Sensitivity analyses were performed considering different survival distributions (exponential distribution, Weibull distribution and log-logistic distribution). Results By using a mixture cure model fitted to PFS and OS data separately, the estimated proportion of LTS for the tafasitamab + LEN combination was 42% (95% CI: 30-55) and 47% (95% CI: 29-66), respectively. The predicted mean survival when mixture cure model was fitted on PFS data was 16.7 years for LTS patients vs 0.5 years for non-LTS patients, yielding 7.3 years for the overall population. Under this mixture cure model, the survival rates of patients with tafasitamab + LEN treatment were 40.2% and 36.0% at 2 and 5 years. Similar results were obtained when the mixture cure model was fitted on OS data. Using a standard parametric model (Weibull distribution), the predicted mean survival in the overall population was 2.8 years fitting PFS data (Figure 1) and 4.5 years fitting OS data (Figure 2). Conclusions PFS and OS KM curves for the L-MIND study reaching a long plateau and not following a Weibull distribution suggest the presence of an LTS subgroup. Standard parametric models may lead to a biased estimation of the OS benefit in such situations. The mixture cure model suggests that the treatment of R/R DLBCL patients with tafasitamab + LEN is associated with a high LTS proportion. The survival rates of patients with tafasitamab + LEN treatment were 40.2% and 36.0% at 2 and 5 years. Disclosures Salles: Takeda:Honoraria;BMS/Celgene:Honoraria, Other: consultancy or advisory role;Debiopharm:Consultancy, Honoraria, Other: consultancy or advisory role;Genmab:Honoraria, Other;Karyopharm:Honoraria;Kite, a Gilead Company:Honoraria, Other: consultancy or advisory role ;Epizyme:Honoraria, Other: consultancy or advisory role;Janssen:Honoraria, Other: consultancy or advisory role;Abbvie:Other: consultancy or advisory role;Roche:Honoraria, Other: consultancy or advisory role;Novartis:Honoraria, Other: consultancy or advisory role;MorphoSys:Honoraria, Other: consultancy or advisory role;Autolos:Other: consultancy or advisory role.Goswami:MorphoSys AG:Ended employment in the past 24 months.Bagnardi:MorphoSys AG:Consultancy.Dey:MorphoSys AG:Current Employment.Winderlich:MorphoSys AG:Current Employment.Ambarkhane:MorphoSys AG:Current Employment.Huang:MorphoSys AG:Current Employment.Nowakowski:Curis:Consultancy;Kymera:Consultancy;Kite:Consultancy;Ryvu:Consultancy, Membership on an entity's Board of Directors or advisory committees;Celgene/BMS:Consultancy, Research Funding;Seattle Genetics:Consultancy;MorphoSys:Consultancy, Research Funding;NanoString:Research Funding.
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Lamba, Nayan, and Bryan Iorgulescu. "EPID-17. COMPARATIVE EPIDEMIOLOGY OF PRIMARY BRAIN TUMORS AMONG ADOLESCENTS AND YOUNG ADULTS (AYA)." Neuro-Oncology 23, Supplement_6 (November 2, 2021): vi89. http://dx.doi.org/10.1093/neuonc/noab196.350.
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Abstract INTRODUCTION We utilized national registry data to evaluate the unique epidemiology of primary adolescent and young adult (AYA) brain tumors according to the WHO2016 classification. METHODS AYA patients (15≤age≤39) presenting between 2004-2017 with a brain tumor were identified by ICD-O-3 coding from the National Cancer Database (comprising >70% of newly-diagnosed cancers in the U.S.), and compared to pediatric and adult populations. Epidemiology and overall survival (estimated by Kaplan-Meier techniques and multivariable Cox regression) were assessed by WHO2016 tumor type. RESULTS 108,705 AYA brain tumor patients were identified (56.9% female), compared to 23,928 pediatric (46.8% female) and 748,272 adult (55.6% female) patients. Among the 69.4% of AYA brain tumors with pathological diagnosis, diffuse gliomas (31.4%), sellar tumors (19.2%), and meningiomas (15.3%) predominated in both sexes. Diffuse glioma (31.4%), sellar (19.2%), cranial nerve (7.3%), and mesenchymal non-meningothelial (4.1%) tumors represented a greater proportion of AYA brain tumors than in either pediatric or adult populations. A majority of all intracranial GCTs (59.2%) and neuronal & mixed neuronal-glial tumors (51.6%) presented during AYA. Although the prevalence of diffuse gliomas was similar between AYAs and adults, AYA gliomas were more likely to be grade 2-3 astrocytomas (38.9% vs 14.3%) and oligodendrogliomas (19.3% vs 4.3%) than in adults. GBMs represented 76.0% of adult diffuse gliomas vs. only 25.7% of AYA diffuse gliomas, but with a similar prevalence of MGMT promoter methylation (40.8% vs 38.4%). Notably, 50.7% of AYA PCNSLs were associated with HIV/AIDS, vs only 7.1% in adults (p< 0.001). CONCLUSIONS The distribution, epidemiology, and survival outcomes of primary brain tumors in the AYA population are distinct from their pediatric and adult counterparts. Notably, AYA infiltrative gliomas were more often of lower grade than adults and AYA PCNSL were far more likely to be associated with HIV/AIDS. Primary brain tumors in AYA patients require specialized management.
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Omedo, Irene, Polycarp Mogeni, Teun Bousema, Kirk Rockett, Alfred Amambua-Ngwa, Isabella Oyier, Jennifer C. Stevenson, et al. "Micro-epidemiological structuring of Plasmodium falciparum parasite populations in regions with varying transmission intensities in Africa." Wellcome Open Research 2 (September 8, 2017): 10. http://dx.doi.org/10.12688/wellcomeopenres.10784.2.
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Background: The first models of malaria transmission assumed a completely mixed and homogeneous population of parasites. Recent models include spatial heterogeneity and variably mixed populations. However, there are few empiric estimates of parasite mixing with which to parametize such models. Methods: Here we genotype 276 single nucleotide polymorphisms (SNPs) in 5199 P. falciparum isolates from two Kenyan sites (Kilifi county and Rachuonyo South district) and one Gambian site (Kombo coastal districts) to determine the spatio-temporal extent of parasite mixing, and use Principal Component Analysis (PCA) and linear regression to examine the relationship between genetic relatedness and distance in space and time for parasite pairs. Results: Using 107, 177 and 82 SNPs that were successfully genotyped in 133, 1602, and 1034 parasite isolates from The Gambia, Kilifi and Rachuonyo South district, respectively, we show that there are no discrete geographically restricted parasite sub-populations, but instead we see a diffuse spatio-temporal structure to parasite genotypes. Genetic relatedness of sample pairs is predicted by relatedness in space and time. Conclusions: Our findings suggest that targeted malaria control will benefit the surrounding community, but unfortunately also that emerging drug resistance will spread rapidly through the population.