NON-PULSITILE SHEAR DRIVEN ANNULAR FLOW-BOILING INVESTIGATIONS

The main goal of this correlations-based modeling investigation is to undertake a preemptive analysis on expected measurement values (of selected flow variables) that may be realized during the implementation/completion of the ongoing experimental endeavors dealing with non-pulsatile steady operations of the innovative flow boiler. The correlation models do not accurately predict the heat transfer coefficients or pressure drops due to the assumptions lumped into the development of the correlations. At the conclusion of the investigation, a tool was created that provides rough order of magnitude estimates of pressure drop and local heat transfer rates. The approach is also recommended for finding or developing HTC correlations that have better compatibility with experimental results to be obtained for innovative boiler operations - eliminating to the significant differences seen in the predictions between experimental and modeling approaches

Gamete compatibility genes in mammals: candidates, applications and a potential path forward

Published VersionFertilization represents a critical stage in biology, where successful alleles of a previous generation are shuffled into new arrangements and subjected to the forces of selection in the next generation. Although much research has been conducted on how variation in morphological and behavioural traits lead to variation in fertilization patterns, surprisingly little is known about fertilization at a molecular level, and specifically about how genes expressed on the sperm and egg themselves influence fertilization patterns. In mammals, several genes have been identified whose products are expressed on either the sperm or the egg, and which influence the fertilization process, but the specific mechanisms are not yet known. Additionally, in 2014 an interacting pair of proteins was identified: ‘Izumo’ on the sperm, and ‘Juno’ on the egg. With the identification of these genes comes the first opportunity to understand the molecular aspects of fertilization in mammals, and to identify how the genetic characteristics of these genes influence fertilization patterns. Here, we review recent progress in our understanding of fertilization and gamete compatibility in mammals, which should provide a helpful guide to researchers interested in untangling the molecular mechanisms of fertilization and the resulting impacts on population biology and evolutionary processes

Genetic examination of historical North Atlantic right whale (Eubalaena glacialis) bone specimens from the eastern North Atlantic: Insights into species history, transoceanic population structure, and genetic diversity

Species monitoring and conservation is increasingly challenging under current climate change scenarios. For the North Atlantic right whale (Eubalaena glacialis) this challenge is heightened by the added effects of complicated and uncertain past species demography. Right whales once had a much wider distribution across the North Atlantic Ocean, although the degree to which right whales in the western and eastern North Atlantic were genetically isolated remains unknown. We analyzed DNA from 24 4th–20th century (CE) right whale bone specimens that were collected from 10 historical and archaeological sites in Iceland, the Faroe Islands, and Scotland. Following mtDNA species identification, we obtained 15-locus nuclear microsatellite profiles from a subset of eight specimens and compared these to contemporary data from animals remaining in the western North Atlantic population. While some specimens share mtDNA haplotypes with the contemporary population, several new haplotypes were found. Moderate mtDNA and nuclear differentiation between the two regions was identified (mtDNA: FST = 0.0423, ΦST = 0.041; nuclear DNA: FST = 0.024). Interpretation of the relationships between animals in the two regions is not simple, and this research highlights the difficulty in conducting such assessments in species with complex histories of unknown structure prior to extensive exploitation.publishedVersio

Recent demographic survey of the Radiated Tortoise (Astrochelys radiata) in southwest Madagascar

Abstract.—Effective management strategies for at-risk chelonian populations require sound knowledge of populationdemographics. Previous research on the Critically Endangered Radiated Tortoise, Astrochelys radiata (Shaw 1802),revealed a trend of increasing male bias in the sex ratio and a concomitant decrease in the proportion of juveniles inLavavolo, southern Madagascar. This location is one of the few remaining sites with a high concentration of this speciesand was last studied ten years ago. The aim of our study was to provide an updated snapshot of Radiated Tortoisedemographics at Lavavolo, which, when combined with previous studies, will provide insight into changes over 20years (1999–2019). Additionally, we provide the first assessment on the impact of soil types (calcareous, ferruginous,and sandy) on the distribution of individuals across the site. We used mark-recapture data to determine the sex ratio,age structure, and distribution of size classes. Overall, the study site contained mostly adults (76.87%) with only afew juveniles (23.13%). Though the proportion of juveniles is low, it has increased over the last ten years. However,the sex ratio has become increasingly skewed towards males, 1.8:1. We did not find any significant difference in sexratios between soil types, but there were significant differences in the distribution of size classes, with the smallest sizeclass 0–8 cm most prevalent in sandy soil and the juvenile size class 17–24 cm most frequent in ferruginous soil. Mostjuvenile size classes were less common than expected on the calcareous soil. In general, populations located on calcareoussoil appear to be more vulnerable, potentially due to the long-term existence of poaching activities in this habitat

Assessment of the extirpated Maritimes walrus using morphological and ancient DNA analysis

Publisher's Version/PDFSpecies biogeography is a result of complex events and factors associated with climate change, ecological interactions, anthropogenic impacts, physical geography, and evolution. To understand the contemporary biogeography of a species, it is necessary to understand its history. Specimens from areas of localized extinction are important, as extirpation of species from these areas may represent the loss of unique adaptations and a distinctive evolutionary trajectory. The walrus (Odobenus rosmarus) has a discontinuous circumpolar distribution in the arctic and subarctic that once included the southeastern Canadian Maritimes region. However, exploitation of the Maritimes population during the 16th-18th centuries led to extirpation, and the species has not inhabited areas south of 55°N for ∼250 years. We examined genetic and morphological characteristics of specimens from the Maritimes, Atlantic (O. r. rosmarus) and Pacific (O. r. divergens) populations to test the hypothesis that the first group was distinctive. Analysis of Atlantic and Maritimes specimens indicated that most skull and mandibular measurements were significantly different between the Maritimes and Atlantic groups and discriminant analysis of principal components confirmed them as distinctive groups, with complete isolation of skull features. The Maritimes walrus appear to have been larger animals, with larger and more robust tusks, skulls and mandibles. The mtDNA control region haplotypes identified in Maritimes specimens were unique to the region and a greater average number of nucleotide differences were found between the regions (Atlantic and Maritimes) than within either group. Levels of diversity (h and π) were lower in the Maritimes, consistent with other studies of species at range margins. Our data suggest that the Maritimes walrus was a morphologically and genetically distinctive group that was on a different evolutionary path from other walrus found in the north Atlantic

Genetic connectivity among swarming sites in the wide ranging and recently declining little brown bat (Myotis lucifugus)

Publisher's Version/PDFCharacterizing movement dynamics and spatial aspects of gene flow within a species permits inference on population structuring. As patterns of structuring are products of historical and current demographics and gene flow, assessment of structure through time can yield an understanding of evolutionary dynamics acting on populations that are necessary to inform management. Recent dramatic population declines in hibernating bats in eastern North America from white-nose syndrome have prompted the need for information on movement dynamics for multiple bat species. We characterized population genetic structure of the little brown bat, Myotis lucifugus, at swarming sites in southeastern Canada using 9 nuclear microsatellites and a 292-bp region of the mitochondrial genome. Analyses of FST, &Phi;ST, and Bayesian clustering (STRUCTURE) found weak levels of genetic structure among swarming sites for the nuclear and mitochondrial genome (Global FST = 0.001, P &lt; 0.05, Global &Phi;ST = 0.045, P &lt; 0.01, STRUCTURE K = 1) suggesting high contemporary gene flow. Hierarchical AMOVA also suggests little structuring at a regional (provincial) level. Metrics of nuclear genetic structure were not found to differ between males and females suggesting weak asymmetries in gene flow between the sexes. However, a greater degree of mitochondrial structuring does support male-biased dispersal long term. Demographic analyses were consistent with past population growth and suggest a population expansion occurred from approximately 1250 to 12,500 BP, following Pleistocene deglaciation in the region. Our study suggests high gene flow and thus a high degree of connectivity among bats that visit swarming sites whereby mainland areas of the region may be best considered as one large gene pool for management and conservation.</p

Assessment of ring-tailed lemur \u3ci\u3eLemur catta\u3c/i\u3e populations in south-western Madagascar

Anthropogenic activities are negatively affecting the flora and fauna of Madagascar, including its Endangered flagship lemur species, the ring-tailed lemur Lemur catta. Population numbers at some sites are rapidly declining, yet much of the species’ habitat is insufficiently surveyed. Because widespread population assessments are critical to guiding conservation management strategies, additional data are needed to monitor L. catta population trends and to identify the limits of their geographical range. Here we report survey results confirming the presence of this species at 65 of 83 sites in southern and south-western Madagascar, including three subpopulations that were previously considered likely to be locally extinct. We identified a minimum of 792 L. catta individuals (summing only maximum group sizes at each site) and as many as 1,221 individuals (using estimated population counts). These findings help refine the distribution of L. catta and reaffirm their presence in areas of their historical geographical range. Identifying species occupancy at sites such as these provides valuable data to support species conservation, but also highlights the need for additional surveys throughout the range of the species

Postcopulatory selection for dissimilar gametes maintains heterozygosity in the endangered North Atlantic right whale

Publisher's Version/PDFAlthough small populations are expected to lose genetic diversity through genetic drift and inbreeding, a number of mechanisms exist that could minimize this genetic decline. Examples include mate choice for unrelated mates and fertilization patterns biased toward genetically dissimilar gametes. Both processes have been widely documented, but the long-term implications have received little attention. Here, we combined over 25 years of field data with high-resolution genetic data to assess the long-term impacts of biased fertilization patterns in the endangered North Atlantic right whale. Offspring have higher levels of microsatellite heterozygosity than expected from this gene pool (effect size = 0.326, P < 0.011). This pattern is not due to precopulatory mate choice for genetically dissimilar mates (P < 0.600), but instead results from postcopulatory selection for gametes that are genetically dissimilar (effect size = 0.37, P < 0.003). The long-term implication is that heterozygosity has slowly increased in calves born throughout the study period, as opposed to the slight decline that was expected. Therefore, this mechanism represents a natural means through which small populations can mitigate the loss of genetic diversity over time

Population Genetic Structure Within and among Seasonal Site Types in the Little Brown Bat (Myotis lucifugus) and the Northern Long-Eared Bat (M. septentrionalis)

Publisher's version/PDFDuring late summer and early autumn, temperate bats migrate from their summering sites to swarming sites, where mating likely occurs. However, the extent to which individuals of a single summering site migrate to the same swarming site, and vice versa, is not known. We examined the migratory connectivity between summering and swarming sites in two temperate, North American, bat species, the little brown bat (Myotis lucifugus) and the northern long-eared bat (Myotis septentrionalis). Using mitochondrial and microsatellite DNA markers, we examined population structuring within and among summering and swarming sites. Both species exhibited moderate degrees of mitochondrial DNA differentiation (little brown bat: F[subscript ST(SWARMING)] = 0.093, F[subscript ST(SWARMING)] = 0.052; northern long-eared bat: F[subscript ST(SWARMING)] = 0.117, F[subscript ST(SWARMING)] = 0.043) and little microsatellite DNA differentiation among summering and among swarming sites. Haplotype diversity was significantly higher at swarming sites than summering sites, supporting the idea that swarming sites are comprised of individuals from various summering sites. Further, pairwise analyses suggest that swarming sites are not necessarily comprised of only individuals from the most proximal summering colonies.Funding for this work was provided by The Canadian Wildlife Federation, Nova Scotia Power, Eon Wind Electric, Shear Wind Inc., The New Brunswick Museum, New Brunswick Wildlife Trust Fund, Bat Conservation International, and the Natural Sciences and Engineering Research Council (Discovery Grant 283217-2010; CRDG 418936-11) Canadian Wildlife Federation: http://www.cwf-fcf.org/en/. Nova Scotia Power: https://www.nspower.ca/en/home/default.aspx. Eon Wind Electric: http://www.eonwind.com. Shear Wind Inc.: http://www.shearwind.com. The New Brunswick Museum: http://www.nbm-mnb.ca. New Brunswick Wildlife Trust Fund: http://www.nbwtf.ca/eindex.asp. Bat Conservation International: http://www.batcon.org. Natural Sciences and Engineering Research Council (Discovery Grant 283217-2010; CRDG 418936-11): http://www.nserc-crsng.gc.ca/index_eng.asp. Note: each industrial funder has agreed to the publishing of this paper

The Lantern Vol. 50, No. 1, Fall 1983

• Reaching for My Dream • All Hail • Appreciation • Egotism • Me (Dedicated to...) • Butterfly • Balloon and Bird • Never Again • Mother • The Deaf Ears • Healing • Distress • Silent Death • Whose Reality Is It Anyway? • To Helen • Luna Llena y Soledad • Saved • Jenny • Slope • A Poem in C Minor • A Birth of Proficiency • The Traveling Man • Competing With the Sea • To R. • The Child • And Besides • An Actress\u27 Demise • A Loving Tribute to Francis • Rapunzel • Memorieshttps://digitalcommons.ursinus.edu/lantern/1123/thumbnail.jp