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Sample records for temperature-dependent sex determination

  1. Yolk-albumen testosterone in a lizard with temperature-dependent sex determination: relation with development.

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    Huang, Victoria; Bowden, Rachel M; Crews, David

    2013-06-01

    The leopard gecko (Eublepharis macularius) exhibits temperature-dependent sex determination as well as temperature-influenced polymorphisms. Research suggests that in oviparous reptiles with temperature-dependent sex determination, steroid hormones in the yolk might influence sex determination and sexual differentiation. From captive leopard geckos that were all from the same incubation temperature regime, we gathered freshly laid eggs, incubated them at one of two female-biased incubation temperatures (26 or 34°C), and measured testosterone content in the yolk-albumen at early or late development. No differences in the concentration of testosterone were detected in eggs from different incubation temperatures. We report testosterone concentrations in the yolk-albumen were higher in eggs of late development than early development at 26°C incubation temperatures, a finding opposite that reported in other TSD reptiles studied to date. Copyright © 2013. Published by Elsevier Inc.

  2. A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle

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    Schroeder, Anthony L.; Metzger, Kelsey J.; Miller, Alexandra; Rhen, Turk

    2016-01-01

    Temperature-dependent sex determination (TSD) was described nearly 50 years ago. Researchers have since identified many genes that display differential expression at male- vs. female-producing temperatures. Yet, it is unclear whether these genes (1) are involved in sex determination per se, (2) are downstream effectors involved in differentiation of ovaries and testes, or (3) are thermo-sensitive but unrelated to gonad development. Here we present multiple lines of evidence linking CIRBP to sex determination in the snapping turtle, Chelydra serpentina. We demonstrate significant associations between a single nucleotide polymorphism (SNP) (c63A > C) in CIRBP, transcript levels in embryonic gonads during specification of gonad fate, and sex in hatchlings from a thermal regime that produces mixed sex ratios. The A allele was induced in embryos exposed to a female-producing temperature, while expression of the C allele did not differ between female- and male-producing temperatures. In accord with this pattern of temperature-dependent, allele-specific expression, AA homozygotes were more likely to develop ovaries than AC heterozygotes, which, in turn, were more likely to develop ovaries than CC homozygotes. Multiple regression using SNPs in CIRBP and adjacent loci suggests that c63A > C may be the causal variant or closely linked to it. Differences in CIRBP allele frequencies among turtles from northern Minnesota, southern Minnesota, and Texas reflect small and large-scale latitudinal differences in TSD pattern. Finally, analysis of CIRBP protein localization reveals that CIRBP is in a position to mediate temperature effects on the developing gonads. Together, these studies strongly suggest that CIRBP is involved in determining the fate of the bipotential gonad. PMID:26936926

  3. Molecular mechanisms of temperature-dependent sex determination in the context of ecological developmental biology.

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    Matsumoto, Yuiko; Crews, David

    2012-05-06

    Temperature-dependent sex determination (TSD) is a prime example of phenotypic plasticity in that gonadal sex is determined by the temperature of the incubating egg. In the red-eared slider turtle (Trachemys scripta), the effect of temperature can be overridden by exogenous ligands, i.e., sex steroid hormones and steroid metabolism enzyme inhibitors, during the temperature-sensitive period (TSP) of development. Precisely how the physical signal of temperature is transduced into a biological signal that ultimately results in sex determination remains unknown. In this review, we discuss the sex determining pathway underlying TSD by focusing on two candidate sex determining genes, Forkhead box protein L2 (FoxL2) and Doublesex mab3- related transcription factor 1 (Dmrt1). They appear to be involved in transducing the environmental temperature signal into a biological signal that subsequently determines gonadal sex. FoxL2 and Dmrt1 exhibit gonad-typical patterns of expression in response to temperature during the TSP in the red-eared slider turtle. Further, the biologically active ligands regulate the expression of FoxL2 and Dmrt1 during development to modify gonad trajectory. The precise regulatory mechanisms of expression of these genes by temperature or exogenous ligands are not clear. However, the environment often influences developmental gene expression by altering the epigenetic status in regulatory regions. Here, we will discuss if the regulation of FoxL2 and Dmrt1 expression by environment is mediated through epigenetic mechanisms during development in species with TSD. Published by Elsevier Ireland Ltd.

  4. Segregating variation for temperature-dependent sex determination in a lizard.

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    Rhen, T; Schroeder, A; Sakata, J T; Huang, V; Crews, D

    2011-04-01

    Temperature-dependent sex determination (TSD) was first reported in 1966 in an African lizard. It has since been shown that TSD occurs in some fish, several lizards, tuataras, numerous turtles and all crocodilians. Extreme temperatures can also cause sex reversal in several amphibians and lizards with genotypic sex determination. Research in TSD species indicates that estrogen signaling is important for ovary development and that orthologs of mammalian genes have a function in gonad differentiation. Nevertheless, the mechanism that actually transduces temperature into a biological signal for ovary versus testis development is not known in any species. Classical genetics could be used to identify the loci underlying TSD, but only if there is segregating variation for TSD. Here, we use the 'animal model' to analyze inheritance of sexual phenotype in a 13-generation pedigree of captive leopard geckos, Eublepharis macularius, a TSD reptile. We directly show genetic variance and genotype-by-temperature interactions for sex determination. Additive genetic variation was significant at a temperature that produces a female-biased sex ratio (30°C), but not at a temperature that produces a male-biased sex ratio (32.5°C). Conversely, dominance variance was significant at the male-biased temperature (32.5°C), but not at the female-biased temperature (30°C). Non-genetic maternal effects on sex determination were negligible in comparison with additive genetic variance, dominance variance and the primary effect of temperature. These data show for the first time that there is segregating variation for TSD in a reptile and consequently that a quantitative trait locus analysis would be practicable for identifying the genes underlying TSD.

  5. Embryonic origin of mate choice in a lizard with temperature-dependent sex determination.

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    Putz, Oliver; Crews, David

    2006-01-01

    Individual differences in the adult sexual behavior of vertebrates are rooted in the fetal environment. In the leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), hatchling sex ratios differ between incubation temperatures, as does sexuality in same-sex animals. This variation can primarily be ascribed to the temperature having direct organizing actions on the brain. Here we demonstrate that embryonic temperature can affect adult mate choice in the leopard gecko. Given the simultaneous choice between two females from different incubation temperatures (30.0 and 34.0 degrees C), males from one incubation temperature (30.0 degrees C) preferred the female from 34.0 degrees C, while males from another incubation temperature (32.5 degrees C) preferred the female from 30.0 degrees C. We suggest that this difference in mate choice is due to an environmental influence on brain development leading to differential perception of opposite-sex individuals. This previously unrecognized modulator of adult mate choice lends further support to the view that mate choice is best understood in the context of an individual's entire life-history. Thus, sexual selection results from a combination of the female's as well as the male's life history. Female attractiveness and male choice therefore are complementary. Copyright 2005 Wiley Periodicals, Inc.

  6. Temperature-dependent sex determination modulates cardiovascular maturation in embryonic snapping turtles Chelydra serpentina.

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    Alvine, Travis; Rhen, Turk; Crossley, Dane A

    2013-03-01

    We investigated sex differences in cardiovascular maturation in embryos of the snapping turtle Chelydra serpentina, a species with temperature-dependent sex determination. One group of eggs was incubated at 26.5°C to produce males. Another group of eggs was incubated at 26.5°C until embryos reached stage 17; eggs were then shifted to 31°C for 6 days to produce females, and returned to 26.5°C for the rest of embryogenesis. Thus, males and females were at the same temperature when autonomic tone was determined and for most of development. Cholinergic blockade increased resting blood pressure (P(m)) and heart rate (f(H)) in both sexes at 75% and 90% of incubation. However, the magnitude of the f(H) response was enhanced in males compared with females at 90% of incubation. β-adrenergic blockade increased P(m) at 75% of incubation in both sexes but had no effect at 90% of incubation. β-adrenergic blockade reduced f(H) at both time points but produced a stronger response at 90% versus 75% of incubation. We found that α-adrenergic blockade decreased P(m) in both sexes at 75% and 90% of incubation and decreased f(H) at 75% of incubation in both sexes. At 90% of incubation, f(H) decreased in females but not males. Although these data clearly demonstrate sexual dimorphism in the autonomic regulation of cardiovascular physiology in embryos, further studies are needed to test whether differences are caused by endocrine signals from gonads or by a hormone-independent temperature effect.

  7. Temperature-dependent sex determination in the leopard gecko, Eublepharis macularius.

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    Viets, B E; Tousignant, A; Ewert, M A; Nelson, C E; Crews, D

    1993-05-01

    The leopard gecko, Eublepharis macularius, has temperature-dependent sex determination (TSD). Previous reports have shown that females are produced predominantly at cool incubation temperatures and males are produced predominantly at warm incubation temperatures (Pattern Ib). We report here that incubation at even higher temperatures (34 and 35 degrees C) produces mostly females (Pattern II). The lethal maximum constant incubation temperature for this species appears to be just above 35 degrees C. Although a previous study indicated that females from a warm incubation temperature (32 degrees C) failed to lay eggs, we found that 12 of 14 mature females incubated at 32.5 degrees C, and 5 of 6 mature females incubated at 34 degrees C produced fertile eggs and viable hatchlings.

  8. Sex determination and differentiation in Aurelia sp.1: the absence of temperature dependence

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    Liu, Chunsheng; Gu, Zhifeng; Xing, Mengxin; Sun, Yun; Chen, Siqing; Chen, Zhaoting

    2018-03-01

    Cnidarians, being regarded as `basal' metazoan animals, are considered to have relatively high plasticity in terms of sex reversal. In this study we used an experimental approach to demonstrate sexual differentiation and plasticity in benthic polyps and pelagic medusae of Aurelia sp.1 maintained at different temperatures. Results indicated that in Aurelia sp.1, sex differentiation has been determined at the polyp stage and that all medusae originating from a given polyp are, phenotypically, of the same sex. In addition, the sex of polyps budding from the same clone (either male or female) at different temperatures appears to be the same as that of the parent. The sex of medusae that had originated from a known-sex polyp was observed to remain the same as that of the parent, irrespective of differences in strobilation or rearing temperatures. These results indicate that the mechanism of sex determination of Aurelia sp.1. is not influenced by prevailing temperature regimes. A comparison of variability in terms of sexual plasticity of Aurelia sp.1 with that of Hydrozoa and Anthozoa suggests that species characterized by a free-swimming medusa life stage have a high dispersal potential, which probably results in a lower rate of sex reversal.

  9. Constraints on temperature-dependent sex determination in the leopard gecko (Eublepharis macularius): response to Kratochvil et al.

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    Huang, Victoria; Sakata, Jon T; Rhen, Turk; Coomber, Patricia; Simmonds, Sarah; Crews, David

    2008-12-01

    Kratochvil et al. (Naturwissenschaften 95:209-215, 2008) reported recently that in the leopard gecko (Eublepharis macularius) of the family Eublepharidae with temperature-dependent sex determination (TSD), clutches in which eggs were incubated at the same temperature produce only same-sex siblings. Interpreting this result in light of studies of sex steroid hormone involvement in sex determination, they suggested that maternally derived yolk steroid hormones could constrain sex-determining mechanisms in TSD reptiles. We have worked extensively with this species and have routinely incubated clutches at constant temperatures. To test the consistency of high frequency same-sex clutches across different incubation temperatures, we examined our records of clutches at the University of Texas at Austin from 1992 to 2001. We observed that clutches in which eggs were incubated at the same incubation temperature produced mixed-sex clutches as well as same-sex clutches. Furthermore, cases in which eggs within a clutch were separated and incubated at different temperatures produced the expected number of mixed-sex clutches. These results suggest that maternal influences on sex determination are secondary relative to incubation temperature effects.

  10. The ecology and evolution of temperature-dependent reaction norms for sex determination in reptiles: a mechanistic conceptual model.

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    Pezaro, Nadav; Doody, J Sean; Thompson, Michael B

    2017-08-01

    Sex-determining mechanisms are broadly categorised as being based on either genetic or environmental factors. Vertebrate sex determination exhibits remarkable diversity but displays distinct phylogenetic patterns. While all eutherian mammals possess XY male heterogamety and female heterogamety (ZW) is ubiquitous in birds, poikilothermic vertebrates (fish, amphibians and reptiles) exhibit multiple genetic sex-determination (GSD) systems as well as environmental sex determination (ESD). Temperature is the factor controlling ESD in reptiles and temperature-dependent sex determination (TSD) in reptiles has become a focal point in the study of this phenomenon. Current patterns of climate change may cause detrimental skews in the population sex ratios of reptiles exhibiting TSD. Understanding the patterns of variation, both within and among populations and linking such patterns with the selection processes they are associated with, is the central challenge of research aimed at predicting the capacity of populations to adapt to novel conditions. Here we present a conceptual model that innovates by defining an individual reaction norm for sex determination as a range of incubation temperatures. By deconstructing individual reaction norms for TSD and revealing their underlying interacting elements, we offer a conceptual solution that explains how variation among individual reaction norms can be inferred from the pattern of population reaction norms. The model also links environmental variation with the different patterns of TSD and describes the processes from which they may arise. Specific climate scenarios are singled out as eco-evolutionary traps that may lead to demographic extinction or a transition to either male or female heterogametic GSD. We describe how the conceptual principles can be applied to interpret TSD data and to explain the adaptive capacity of TSD to climate change as well as its limits and the potential applications for conservation and management

  11. Inheritance of nesting behaviour across natural environmental variation in a turtle with temperature-dependent sex determination.

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    McGaugh, Suzanne E; Schwanz, Lisa E; Bowden, Rachel M; Gonzalez, Julie E; Janzen, Fredric J

    2010-04-22

    Nesting behaviour is critical for reproductive success in oviparous organisms with no parental care. In organisms where sex is determined by incubation temperature, nesting behaviour may be a prime target of selection in response to unbalanced sex ratios. To produce an evolutionary change in response to sex-ratio selection, components of nesting behaviour must be heritable. We estimated the field heritability of two key components of nesting behaviour in a population of painted turtles (Chrysemys picta) with temperature-dependent sex determination by applying the 'animal model' to a pedigree reconstructed from genotype data. We obtained estimates of low to non-detectable heritability using repeated records across all environments. We then determined environment-specific heritability by grouping records with similar temperatures for the winter preceding the nesting season, a variable known to be highly associated with our two traits of interest, nest vegetation cover and Julian date of nesting. The heritability estimates of nest vegetation cover and Julian date of nesting were qualitatively highest and significant, or nearly so, after hot winters. Additive genetic variance for these traits was not detectable after cold winters. Our analysis suggests that the potential for evolutionary change of nesting behaviour may be dependent on the thermal conditions of the preceding winter, a season that is predicted to be especially subject to climate change.

  12. Gonadal expression of Sf1 and aromatase during sex determination in the red-eared slider turtle (Trachemys scripta), a reptile with temperature-dependent sex determination.

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    Ramsey, Mary; Shoemaker, Christina; Crews, David

    2007-12-01

    Many egg-laying reptiles have temperature-dependent sex determination (TSD), where the offspring sex is determined by incubation temperature during a temperature-sensitive period (TSP) in the middle third of development. The underlying mechanism transducing a temperature cue into an ovary or testis is unknown, but it is known that steroid hormones play an important role. During the TSP, exogenous application of estrogen can override a temperature cue and produce females, while blocking the activity of aromatase (Cyp19a1), the enzyme that converts testosterone to estradiol, produces males from a female-biased temperature. The production of estrogen is a key step in ovarian differentiation for many vertebrates, including TSD reptiles, and temperature-based differences in aromatase expression during the TSP may be a critical step in ovarian determination. Steroidogenic factor-1 (Sf1) is a key gene in vertebrate sex determination and regulates many steroidogenic enzymes, including aromatase. We find that Sf1 and aromatase are differentially expressed during sex determination in the red-eared slider turtle, Trachemys scripta elegans. Sf1 is expressed at higher levels during testis development while aromatase expression increases during ovary determination. We also assayed Sf1 and aromatase response to sex-reversing treatments via temperature or the modulation of estrogen availability. Sf1 expression was redirected to low-level female-specific patterns with feminizing temperature shift or exogenous estradiol application and redirected to more intense male-specific patterns with male-producing temperature shift or inhibition of aromatase activity. Conversely, aromatase expression was redirected to more intense female-specific patterns with female-producing treatment and redirected toward diffuse low-level male-specific patterns with masculinizing sex reversal. Our data do not lend support to a role for Sf1 in the regulation of aromatase expression during slider turtle sex

  13. Incubation temperature and gonadal sex affect growth and physiology in the leopard gecko (Eublepharis macularius), a lizard with temperature-dependent sex determination.

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    Tousignant, A; Crews, D

    1995-05-01

    Temperature-dependent sex determination (TSD), in which the temperature at which an egg incubates determines the sex of the individual, occurs in egg-laying reptiles of three separate orders. Previous studies have shown that the embryonic environment can have effects lasting beyond the period of sex determination. We investigated the relative roles of incubation temperature, exogenous estradiol, and gonadal sex (testis vs. ovary) in the differentiation of adult morphological and physiological traits of the leopard gecko, Eublepharis macularius. The results indicate that incubation temperature, steroid hormones, and gonads interact in the development of morphological and physiological characters with incubation temperature resulting in the greatest differences in adult phenotype. Incubation temperature did not affect reproductive success directly, but may influence offspring survival in natural situations through effects on adult female body size. Postnatal hormones seem to be more influential in the formation of adult phenotypes than prenatal hormones. These results demonstrate that TSD species can be used to investigate the effects of the physical environment on development in individuals without a predetermined genetic sex and thus provide further insight into the roles of gonadal sex and the embryonic environment in sexual differentiation.

  14. The lesser known challenge of climate change: thermal variance and sex-reversal in vertebrates with temperature-dependent sex determination.

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    Jennifer L Neuwald

    Full Text Available Climate change is expected to disrupt biological systems. Particularly susceptible are species with temperature-dependent sex determination (TSD, as in many reptiles. While the potentially devastating effect of rising mean temperatures on sex ratios in TSD species is appreciated, the consequences of increased thermal variance predicted to accompany climate change remain obscure. Surprisingly, no study has tested if the effect of thermal variance around high-temperatures (which are particularly relevant given climate change predictions has the same or opposite effects as around lower temperatures. Here we show that sex ratios of the painted turtle (Chrysemys picta were reversed as fluctuations increased around low and high unisexual mean-temperatures. Unexpectedly, the developmental and sexual responses around female-producing temperatures were decoupled in a more complex manner than around male-producing values. Our novel observations are not fully explained by existing ecological models of development and sex determination, and provide strong evidence that thermal fluctuations are critical for shaping the biological outcomes of climate change.

  15. Conservation of Sex-Linked Markers among Conspecific Populations of a Viviparous Skink, Niveoscincus ocellatus, Exhibiting Genetic and Temperature-Dependent Sex Determination

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    Burridge, Christopher P; Ezaz, Tariq; Wapstra, Erik

    2018-01-01

    Abstract Sex determination systems are exceptionally diverse and have undergone multiple and independent evolutionary transitions among species, particularly reptiles. However, the mechanisms underlying these transitions have not been established. Here, we tested for differences in sex-linked markers in the only known reptile that is polymorphic for sex determination system, the spotted snow skink, Niveoscincus ocellatus, to quantify the genomic differences that have accompanied this transition. In a highland population, sex is determined genetically, whereas in a lowland population, offspring sex ratio is influenced by temperature. We found a similar number of sex-linked loci in each population, including shared loci, with genotypes consistent with male heterogamety (XY). However, population-specific linkage disequilibrium suggests greater differentiation of sex chromosomes in the highland population. Our results suggest that transitions between sex determination systems can be facilitated by subtle genetic differences. PMID:29659810

  16. Steroid signaling system responds differently to temperature and hormone manipulation in the red-eared slider turtle (Trachemys scripta elegans), a reptile with temperature-dependent sex determination.

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    Ramsey, M; Crews, D

    2007-01-01

    Many reptiles, including the red-eared slider turtle (Trachemys scripta elegans), exhibit temperature-dependent sex determination (TSD). Temperature determines gonadal sex during the middle of embryogenesis, or the temperature-sensitive period (TSP), when gonadal sex is labile to both temperature and hormones--particularly estrogen. The biological actions of steroid hormones are mediated by their receptors as defined here as the classic transcriptional regulation of target genes. To elucidate estrogen action during sex determination, we examined estrogen receptor alpha (Esr1, hereafter referred to as ERalpha), estrogen receptor beta (Esr2, hereafter referred to as ERbeta), and androgen receptor (Ar, hereafter referred to as AR) expression in slider turtle gonads before, during and after the TSP, as well as following sex reversal via temperature or steroid hormone manipulation. ERalpha and AR levels spike at the female-producing temperature while ovarian sex is determined, but none of the receptors exhibited sexually dimorphic localization within the gonad prior to morphological differentiation. All three receptors respond differentially to sex-reversing treatments. When shifted to female-producing temperatures, embryos maintain ERalpha and AR expression while ERbeta is reduced. When shifted to male-producing temperatures, medullary expression of all three receptors is reduced. Feminization via estradiol (E(2)) treatment at a male-producing temperature profoundly changed the expression patterns for all three receptors. ERalpha and ERbeta redirected to the cortex in E(2)-created ovaries, while AR medullary expression was transiently reduced. Although warmer incubation temperature and estrogen result in the same endpoint (ovarian development), our results indicate different steroid signaling patterns between temperature- and estrogen-induced feminization. 2007 S. Karger AG, Basel

  17. Distinct sperm nucleus behaviors between genotypic and temperature-dependent sex determination males are associated with replication and expression-related pathways in a gynogenetic fish.

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    Zhu, Yao-Jun; Li, Xi-Yin; Zhang, Jun; Li, Zhi; Ding, Miao; Zhang, Xiao-Juan; Zhou, Li; Gui, Jian-Fang

    2018-06-05

    Coexistence and transition of diverse sex determination strategies have been revealed in some ectothermic species, but the variation between males caused by different sex determination strategies and the underlying mechanism remain unclear. Here, we used the gynogenetic gibel carp (Carassius gibelio) with both genotypic sex determination (GSD) and temperature-dependent sex determination (TSD) strategies to illustrate this issue. We found out that males of GSD and TSD in gibel carp had similar morphology, testicular histology, sperm structure and sperm vitality. However, when maternal individuals were mated with males of GSD, sperm nucleus swelling and fusing with the female pronucleus were observed in the fertilized eggs. On the contrary, when maternal individuals were mated with males of TSD, sperm nucleus remained in the condensed status throughout the whole process. Subsequently, semen proteomics analysis unveiled that DNA replication and gene expression-related pathways were inhibited in the sperm from males of TSD compared to males of GSD, and most differentially expressed proteins associated with DNA replication, transcription and translation were down-regulated. Moreover, via BrdU incorporation and immunofluorescence detection, male nucleus replication was revealed to be present in the fertilized eggs by the sperm from males of GSD, but absent in the fertilized eggs by the sperm from males of TSD. These findings indicate that DNA replication and gene expression-related pathways are associated with the distinct sperm nucleus development behaviors in fertilized eggs in response to the sperm from males of GSD and TSD. And this study is the first attempt to screen the differences between males determined via GSD and TSD in gynogenetic species, which might give a hint for understanding evolutionary adaption of diverse sex determination mechanisms in unisexual vertebrates.

  18. Expression profiles of amhy and major sex-related genes during gonadal sex differentiation and their relation with genotypic and temperature-dependent sex determination in pejerrey Odontesthes bonariensis.

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    Zhang, Yan; Hattori, Ricardo S; Sarida, Munti; García, Estefany L; Strüssmann, Carlos Augusto; Yamamoto, Yoji

    2018-03-15

    To shed light on the mechanisms of and interactions of GSD and TSD in pejerrey, we investigated how the transcriptional profiles of amhy and amha are affected by feminizing (17 °C) and masculinizing (29 °C) temperatures during the critical period of sex determination/differentiation and their relation with the expression profiles of AMH receptor type II (amhrII), gonadal aromatase (cyp19a1a), and 11 beta-hydroxysteroid dehydrogenase 2 (hsd11b2). Careful consideration of the results of this study and all information currently available for this species, including similar analyzes for an intermediate, mixed-sex promoting temperature (25 °C), suggests a model for genotypic/temperature-dependent sex determination and gonadal sex differentiation that involves a) cyp19a1a-dependent, developmentally-programmed ovarian development as the default state that becomes self-sustaining in the absence of a potent and timely masculinizing stimulus, b) early, developmentally-programmed amhy expression and high temperature as masculinization signals that antagonize the putative female pathway by suppressing cyp19a1a expression, c) increasing stress response, cortisol, and the synthesis of the masculinizing androgen 11-keto-testosterone via hsd11b2 with increasing temperature that is important for masculinization in both genotypes but particularly so in XX individuals, and d) an endocrine network with positive/negative feedback mechanisms that ensure fidelity of the male/female pathway once started. The proposed model, albeit tentative and non-all inclusive, accounts for the continuum of responses, from all-females at low temperatures to all-males at high temperatures and for the balanced-, genotype-linked sex ratios obtained at intermediate temperatures, and therefore supports the coexistence of TSD and GSD in pejerrey across the range of viable temperatures for this species. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Effect of hormonal manipulation on sociosexual behavior in adult female leopard geckos (Eublepharis macularius), a species with temperature-dependent sex determination.

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    Flores, D L; Crews, D

    1995-12-01

    Aggressive and sexual behavior in the adult leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), is influenced by the temperature experienced as an egg, as well as by prenatal and perinatal hormones. This study focused on the effects of hormonal manipulation of adult female leopard geckos from different incubation temperatures. Following ovariectomy, females from both all-female (26 degrees C) and male-biased (32.5 degrees C) incubation temperatures exhibited a significant decrease in high-posture (HP) aggression toward male and female stimulus animals. Testosterone treatment attenuated this decrease in HP aggression toward female but not toward male stimulus animals. Ovariectomy also resulted in a loss in attractiveness in both groups of females. Following treatment with testosterone, over 50% of the females were attacked by male stimulus animals, suggesting a change in the pheromonal cues normally secreted by females. Unmanipulated females never exhibit tail vibrations, a male-typical courtship behavior. However, following ovariectomy with testosterone treatment, half of the females from both incubation temperatures exhibited this behavior, indicating an activational effect of testosterone. An effect of incubation temperature on aggression was evident with females from the male-biased incubation temperature exhibiting a greater likelihood of aggression compared to females from the all-female incubation temperature. This effect continued to be detected after hormone manipulation. Ovariectomized females from the all-female incubation temperature were less aggressive even with testosterone treatment toward males, whereas females from the male-biased incubation temperature showed no significant decline in aggression following testosterone treatment, suggesting that individuals from different incubation temperatures may have different sensitivities to hormones.

  20. The platelet-derived growth factor signaling system in snapping turtle embryos, Chelydra serpentina: potential role in temperature-dependent sex determination and testis development.

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    Rhen, Turk; Jangula, Adam; Schroeder, Anthony; Woodward-Bosh, Rikki

    2009-05-01

    The platelet-derived growth factor (Pdgf) signaling system is known to play a significant role during embryonic and postnatal development of testes in mammals and birds. In contrast, genes that comprise the Pdgf system in reptiles have never been cloned or studied in any tissue, let alone developing gonads. To explore the potential role of PDGF ligands and their receptors during embryogenesis, we cloned cDNA fragments of Pdgf-A, Pdgf-B, and receptors PdgfR-alpha and PdgfR-beta in the snapping turtle, a reptile with temperature-dependent sex determination (TSD). We then compared gene expression profiles in gonads from embryos incubated at a male-producing temperature to those from embryos at a female-producing temperature, as well as between hatchling testes and ovaries. Expression of Pdgf-B mRNA in embryonic gonads was significantly higher at a male temperature than at a female temperature, but there was no difference between hatchling testes and ovaries. This developmental pattern was reversed for Pdgf-A and PdgfR-alpha mRNA: expression of these genes did not differ in embryos, but diverged in hatchling testes and ovaries. Levels of PdgfR-beta mRNA in embryonic gonads were not affected by temperature and did not differ between testes and ovaries. However, expression of both receptors increased at least an order of magnitude from the embryonic to the post-hatching period. Finally, we characterized expression of these genes in several other embryonic tissues. The brain, heart, and liver displayed unique expression patterns that distinguished these tissues from each other and from intestine, lung, and muscle. Incubation temperature had a significant effect on expression of PdgfR-alpha and PdgfR-beta in the heart but not other tissues. Together, these findings demonstrate that temperature has tissue specific effects on the Pdgf system and suggest that Pdgf signaling is involved in sex determination and the ensuing differentiation of testes in the snapping turtle.

  1. Steroid Signaling and Temperature-Dependent Sex Determination – Reviewing the Evidence for Early Action of Estrogen during Ovarian Determination in the Red-Eared Slider Turtle (Trachemys scripta elegans)

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    Ramsey, Mary; Crews, David

    2009-01-01

    The developmental processes underlying gonadal differentiation are conserved across vertebrates, but the triggers initiating these trajectories are extremely variable. The red-eared slider turtle (Trachemys scripta elegans) exhibits temperature-dependent sex determination (TSD), a system where incubation temperature during a temperature-sensitive period of development determines offspring sex. However, gonadal sex is sensitive to both temperature and hormones during this period – particularly estrogen. We present a model for temperature-based differences in aromatase expression as a critical step in ovarian determination. Localized estrogen production facilitates ovarian development while inhibiting male-specific gene expression. At male-producing temperatures aromatase is not upregulated, thereby allowing testis development. PMID:18992835

  2. Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development.

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    Radhakrishnan, Srihari; Literman, Robert; Neuwald, Jennifer; Severin, Andrew; Valenzuela, Nicole

    2017-01-01

    Vertebrate sexual fate is decided primarily by the individual's genotype (GSD), by the environmental temperature during development (TSD), or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR) of painted turtles (Chrysemys picta TSD) before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD), to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1), Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr) were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock) were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling) potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist) were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2) and female (Crabp2 and Hspb1

  3. Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development.

    Directory of Open Access Journals (Sweden)

    Srihari Radhakrishnan

    Full Text Available Vertebrate sexual fate is decided primarily by the individual's genotype (GSD, by the environmental temperature during development (TSD, or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR of painted turtles (Chrysemys picta TSD before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD, to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1, Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2 and female (Crabp2 and

  4. Adrenal-kidney-gonad complex measurements may not predict gonad-specific changes in gene expression patterns during temperature-dependent sex determination in the red-eared slider turtle (Trachemys scripta elegans).

    Science.gov (United States)

    Ramsey, Mary; Crews, David

    2007-08-01

    Many turtles, including the red-eared slider turtle (Trachemys scripta elegans) have temperature-dependent sex determination in which gonadal sex is determined by temperature during the middle third of incubation. The gonad develops as part of a heterogenous tissue complex that comprises the developing adrenal, kidney, and gonad (AKG complex). Owing to the difficulty in excising the gonad from the adjacent tissues, the AKG complex is often used as tissue source in assays examining gene expression in the developing gonad. However, the gonad is a relatively small component of the AKG, and gene expression in the adrenal-kidney (AK) compartment may interfere with the detection of gonad-specific changes in gene expression, particularly during early key phases of gonadal development and sex determination. In this study, we examine transcript levels as measured by quantitative real-time polymerase chain reaction for five genes important in slider turtle sex determination and differentiation (AR, ERalpha, ERbeta, aromatase, and Sf1) in AKG, AK, and isolated gonad tissues. In all cases, gonad-specific gene expression patterns were attenuated in AKG versus gonad tissue. All five genes were expressed in the AK in addition to the gonad at all stages/temperatures. Inclusion of the AK compartment masked important changes in gonadal gene expression. In addition, AK and gonad expression patterns are not additive, and gonadal gene expression cannot be predicted from intact AKG measurements. (c) 2007 Wiley-Liss, Inc.

  5. Determination of the temperature dependence of tungsten erosion

    International Nuclear Information System (INIS)

    Maier, H.; Greuner, H.; Toussaint, U. von; Balden, M.; Böswirth, B.; Elgeti, S.

    2015-01-01

    We present the results of erosion measurements on actively cooled tungsten samples at quasi-constant surface temperature conditions performed in the high heat flux facility GLADIS. The samples were exposed to a H beam at a central power density of 10 MW/m 2 up to a fluence of 10 26 m −2 . We observe a weak temperature dependence of the erosion yield. The data are compared with similar data obtained from loading with a H beam with He admixture. Both datasets are analysed in a probabilistic approach. We obtain activation energies of 0.04 eV and 0.06 eV for the cases with and without He, respectively

  6. Sex determination

    Indian Academy of Sciences (India)

    The sex-determining system differs considerably among organisms. Even among insect species, the genetic system for sex-determination is highly diversified. In Drosophila melanogaster, somatic sexual differentiation is regulated by a well characterized genetic hierarchy X : A > Sxl > tra/tra2 > dsx and fru. This cascade ...

  7. Experimental determination of monoethanolamine protonation constant and its temperature dependency

    Directory of Open Access Journals (Sweden)

    Ma’mun Sholeh

    2017-01-01

    Full Text Available Carbon dioxide as one of the major contributors to the global warming problem is produced in large quantities by many important industries and its emission seems to rise from year to year. Aminebased absorption is one of the methods to capture CO2 from its sources. As a reactive system, mass transfer and chemical reaction take place simultaneously. In a vapor-liquid equilibrium model for the CO2-amine-water system, some parameters such as mass transfer coefficients and chemical equilibrium constants need to be known. However, some parameters could be determined experimentally and the rests could be regressed from the model. The protonation constant (pKa, as one of the model parameters, could then be measured experimentally. The purpose of this study is to measure the pKa of monoethanolamine (MEA at a range of temperatures from 303 to 330K by a potentiometric titration method. The experimental data obtained were in a good agreement with the literature data. The pKa data from this work together with those from the literature were then correlated in an empirical correlation to be used for future research.

  8. Effects of age and sociosexual experience on the morphology and metabolic capacity of brain nuclei in the leopard gecko (Eublepharis macularius), a lizard with temperature-dependent sex determination.

    Science.gov (United States)

    Crews, D; Coomber, P; Gonzalez-Lima, F

    1997-05-30

    In vertebrates having sex chromosomes, sexual behavior is influenced by steroid hormones throughout life as well as by the cumulative experiences of the individual. Because males and females differ genetically as well as hormonally, it would be valuable to distinguish the contribution of sex-specific genes from hormones. In addition, since animals age as they gain sociosexual experience, but do not necessarily gain sociosexual experience as they age, it is important to separate the effects of age from those attributable to experience. The leopard gecko is a lizard lacking sex chromosomes, depending instead upon the temperature during incubation to establish gonadal sex. This effectively removes sex-specific genetic influences from any study of sexual differentiation. Eggs were incubated at either 26 degrees C or 32.5 degrees C, temperatures that produce only female hatchlings or a male-biased sex ratio, respectively. By raising geckoes in isolation and then housing some animals together in breeding groups at different ages after they attained sexual maturity, it was possible to assess the relative effects of age and sociosexual experience on the volume and metabolic capacity of limbic and non-limbic brain areas. In general, males showed more changes compared to females. For example, there was a decrease with age in the volume of the preoptic area and the ventromedial hypothalamus in males, but not in females. Both age and sociosexual experience influenced cytochrome oxidase activity in these and other brain areas. Experienced animals had greater metabolic capacity in nuclei functionally associated with sociosexual behavior in lizards and other vertebrates. For example, cytochrome oxidase activity was higher in the anterior hypothalamus of males, in the ventromedial hypothalamus of both males and females from the male-biased incubation temperature, and in the preoptic area of females from both incubation temperatures. These differences were not paralleled by

  9. Quantification of three steroid hormone receptors of the leopard gecko (Eublepharis macularius), a lizard with temperature-dependent sex determination: their tissue distributions and the effect of environmental change on their expressions.

    Science.gov (United States)

    Endo, Daisuke; Park, Min Kyun

    2003-12-01

    Sex steroid hormones play a central role in the reproduction of all vertebrates. These hormones function through their specific receptors, so the expression levels of the receptors may reflect the responsibility of target organs. However, there was no effective method to quantify the expression levels of these receptors in reptilian species. In this study, we established the competitive-PCR assay systems for the quantification of the mRNA expression levels of three sex steroid hormone receptors in the leopard gecko. These assay systems were successfully able to detect the mRNA expression level of each receptor in various organs of male adult leopard geckoes. The expression levels of mRNA of these receptors were highly various depending on the organs assayed. This is the first report regarding the tissue distributions of sex steroid hormone receptor expressions in reptile. The effects of environmental conditions on these hormone receptor expressions were also examined. After the low temperature and short photoperiod treatment for 6 weeks, only the androgen receptor expression was significantly increased in the testes. The competitive-PCR assay systems established in this report should be applicable for various studies of the molecular mechanism underlying the reproductive activity of the leopard gecko.

  10. DETERMINATION OF TEMPERATURE DISTRIBUTION FOR ANNULAR FINS WITH TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY BY HPM

    Directory of Open Access Journals (Sweden)

    Davood Domairry Ganji

    2011-01-01

    Full Text Available In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity.

  11. Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sørensen, O. H.; Mygind, Jesper

    1978-01-01

    The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature Tc of the Sn films. The temperature dependence of the cosφ conductance is determined from the resonant response at the junction plasma frequency fp...

  12. An analytical method for determining the temperature dependent moisture diffusivities of pumpkin seeds during drying process

    Energy Technology Data Exchange (ETDEWEB)

    Can, Ahmet [Department of Mechanical Engineering, University of Trakya, 22030 Edirne (Turkey)

    2007-02-15

    This paper presents an analytical method, which determines the moisture diffusion coefficients for the natural and forced convection hot air drying of pumpkin seeds and their temperature dependence. In order to obtain scientific data, the pumpkin seed drying process was investigated under both natural and forced hot air convection regimes. This paper presents the experimental results in which the drying air was heated by solar energy. (author)

  13. Temperature-dependent sex-reversal by a transformer-2 gene-edited mutation in the spotted wing drosophila, Drosophila suzukii.

    Science.gov (United States)

    Li, Jianwei; Handler, Alfred M

    2017-09-28

    Female to male sex reversal was achieved in an emerging agricultural insect pest, Drosophila suzukii, by creating a temperature-sensitive point mutation in the sex-determination gene, transformer-2 (tra-2), using CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/CRISPR-associated) homology-directed repair gene-editing. Ds-tra-2 ts2 mutants developed as normal fertile XX and XY adults at permissive temperatures below 20 °C, but at higher restrictive temperatures (26 to 29 °C) chromosomal XX females developed as sterile intersexuals with a predominant male phenotype, while XY males developed with normal morphology, but were sterile. The temperature-dependent function of the Ds-TRA-2 ts2 protein was also evident by the up- and down-regulation of female-specific Ds-Yolk protein 1 (Ds-Yp1) gene expression by temperature shifts during adulthood. This study confirmed the temperature-dependent function of a gene-edited mutation and provides a new method for the more general creation of conditional mutations for functional genomic analysis in insects, and other organisms. Furthermore, it provides a temperature-dependent system for creating sterile male populations useful for enhancing the efficacy of biologically-based programs, such as the sterile insect technique (SIT), to control D. suzukii and other insect pest species of agricultural and medical importance.

  14. Temperature dependence of the calibration factor of radon and radium determination in water samples by SSNTD

    CERN Document Server

    Hunyadi, I; Hakl, J; Baradacs, E; Dezso, Z

    1999-01-01

    The sensitivity of a sup 2 sup 2 sup 6 Ra determination method of water samples by SSNTD was measured as a function of storage temperature during exposure. The method is based on an etched track type radon monitor, which is closed into a gas permeable foil and is immersed in the water sample. The sample is sealed in a glass vessel and stored for an exposure time of 10-30 days. The sensitivity increased more than a factor of two when the storage temperature was raised from 2 deg. C to 30 deg. C. Temperature dependence of the partition coefficient of radon between water and air provides explanation for this dependence. For practical radio- analytical application the temperature dependence of the calibration factor is given by fitting the sensitivity data obtained by measuring sup 2 sup 2 sup 6 Ra standard solutions (in the activity concentration range of 0.1-48.5 kBq m sup - sup 3) at different storage temperatures.

  15. Allelic variant in the anti-Müllerian hormone gene leads to autosomal and temperature-dependent sex reversal in a selected Nile tilapia line.

    Directory of Open Access Journals (Sweden)

    Stephan Wessels

    Full Text Available Owing to the demand for sustainable sex-control protocols in aquaculture, research in tilapia sex determination is gaining momentum. The mutual influence of environmental and genetic factors hampers disentangling the complex sex determination mechanism in Nile tilapia (Oreochromis niloticus. Previous linkage analyses have demonstrated quantitative trait loci for the phenotypic sex on linkage groups 1, 3, and 23. Quantitative trait loci for temperature-dependent sex reversal similarly reside on linkage group 23. The anti-Müllerian hormone gene (amh, located in this genomic region, is important for sexual fate in higher vertebrates, and shows sexually dimorphic expression in Nile tilapia. Therefore this study aimed at detecting allelic variants and marker-sex associations in the amh gene. Sequencing identified six allelic variants. A significant effect on the phenotypic sex for SNP ss831884014 (p<0.0017 was found by stepwise logistic regression. The remaining variants were not significantly associated. Functional annotation of SNP ss831884014 revealed a non-synonymous amino acid substitution in the amh protein. Consequently, a fluorescence resonance energy transfer (FRET based genotyping assay was developed and validated with a representative sample of fish. A logistic linear model confirmed a highly significant effect of the treatment and genotype on the phenotypic sex, but not for the interaction term (treatment: p<0.0001; genotype: p<0.0025. An additive genetic model proved a linear allele substitution effect of 12% in individuals from controls and groups treated at high temperature, respectively. Moreover, the effect of the genotype on the male proportion was significantly higher in groups treated at high temperature, giving 31% more males on average of the three genotypes. In addition, the groups treated at high temperature showed a positive dominance deviation (+11.4% males. In summary, marker-assisted selection for amh variant ss831884014

  16. Experimental determination of the temperature-dependent penetration depth in V3Si

    International Nuclear Information System (INIS)

    Christen, D.K.; Kerchner, H.R.; Sekula, S.T.; Chang, Y.K.

    1984-03-01

    Small angle neutron diffraction from the flux-line lattice (FLL) in a high quality, single crystal of superconducting V 3 Si has been used to deduce the low-field penetration depth lambda (T). An absolute determination is possible because the FLL form factor F/sub hk/ is essentially single-valued in the scattering vector magnitude absolute value of K/sub hk/, as well as nearly London-like at low field. We obtain lambda (0) = 102 +- 1 nm, 20% to 30% larger than previous determinations of the London penetration depth lambda/sub L/ (0). The temperature dependence of lambda (T) is found to deviate from that of the BCS theory. An assessment of the data indicates the most prominent source of the discrepancy is due to strong electron-phonon coupling, and we find 2Δ(0)/k/sub B/T/sub c/ = 3.88 +- 0.07, in reasonable agreement with values found in the literature

  17. Experimental determination of the temperature dependence of metallic work functions at low temperatures. Progress report

    International Nuclear Information System (INIS)

    Pipes, P.B.

    1977-01-01

    Progress made under ERDA Contract No. EY-76-S-02-2314.002 is described. Efforts to gain theoretical insight into the temperature dependence of the contact potential of Nb near the superconducting transition have only been qualitatively successful. Preliminary measurements of adsorbed 4 He gas on the temperature dependence of the contact potentials of metals were performed and compared with a previously developed theory

  18. Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

    International Nuclear Information System (INIS)

    Pedersen, N.F.; Soerensen, O.H.; Mygind, J.

    1978-01-01

    The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature T/sub c/ of the Sn films. The temperature dependence of the cosphi conductance is determined from the resonant response at the junction plasma frequency f/sub p/ as the temperature is decreased from T/sub c/. We used three different schemes for observation of the plasma oscillations: (a) second-harmonic generation (excitation at approx. 4.5 GHz, f/sub p/ approx. 4.5 GHz); (b) mixing (excitations at approx. 9 and approx. 18 GHz, f/sub p/ approx. 9 GHz); (c) parametric half-harmonic oscillation (excitation at approx. 18 GHz, f/sub p/ approx. 9 GHz). Measurements were possible in two temperature intervals; 0.994 or = T/T/sub c/ > or = 0.930, with the result that as the temperature was decreased the cosphi amplitude first increased from about zero to positive values and then at lower temperatures decreased approaching -1 at the lowest temperatures of the experiment

  19. A Review of Sex Determining Mechanisms in Geckos (Gekkota: Squamata)

    OpenAIRE

    Gamble, T.

    2010-01-01

    Geckos are a species-rich clade of reptiles possessing diverse sex determining mechanisms. Some species possess genetic sex determination, with both male and female heterogamety, while other species have temperature-dependent sex determination. I compiled information from the literature on the taxonomic distribution of these sex determining mechanisms in geckos. Using phylogenetic data from the literature, I reconstructed the minimum number of transitions among these sex determining mechanism...

  20. Determining Role of the Chain Mechanism in the Temperature Dependence of the Gas-Phase Rate of Combustion Reactions

    Science.gov (United States)

    Azatyan, V. V.; Bolod'yan, I. A.; Kopylov, N. P.; Kopylov, S. N.; Prokopenko, V. M.; Shebeko, Yu. N.

    2018-05-01

    It is shown that the strong dependence of the rate of gas-phase combustion reactions on temperature is determined by the high values of the reaction rate constants of free atoms and radicals. It is established that with a branched chain mechanism, a special role in the reaction rate temperature dependence is played by positive feedback between the concentrations of active intermediate species and the rate of their change. The role of the chemical mechanism in the temperature dependence of the process rate with and without inhibitors is considered.

  1. DNA methylation of the gonadal aromatase (cyp19a promoter is involved in temperature-dependent sex ratio shifts in the European sea bass.

    Directory of Open Access Journals (Sweden)

    Laia Navarro-Martín

    2011-12-01

    Full Text Available Sex ratio shifts in response to temperature are common in fish and reptiles. However, the mechanism linking temperature during early development and sex ratios has remained elusive. We show in the European sea bass (sb, a fish in which temperature effects on sex ratios are maximal before the gonads form, that juvenile males have double the DNA methylation levels of females in the promoter of gonadal aromatase (cyp19a, the enzyme that converts androgens into estrogens. Exposure to high temperature increased the cyp19a promoter methylation levels of females, indicating that induced-masculinization involves DNA methylation-mediated control of aromatase gene expression, with an observed inverse relationship between methylation levels and expression. Although different CpGs within the sb cyp19a promoter exhibited different sensitivity to temperature, we show that the increased methylation of the sb cyp19a promoter, which occurs in the gonads but not in the brain, is not a generalized effect of temperature. Importantly, these effects were also observed in sexually undifferentiated fish and were not altered by estrogen treatment. Thus, methylation of the sb cyp19a promoter is the cause of the lower expression of cyp19a in temperature-masculinized fish. In vitro, induced methylation of the sb cyp19a promoter suppressed the ability of SF-1 and Foxl2 to stimulate transcription. Finally, a CpG differentially methylated by temperature and adjacent to a Sox transcription factor binding site is conserved across species. Thus, DNA methylation of the aromatase promoter may be an essential component of the long-sought-after mechanism connecting environmental temperature and sex ratios in vertebrate species with temperature-dependent sex determination.

  2. Determination of temperature dependant viscosity values of lubricants via simultaneous measurements of refractive index

    International Nuclear Information System (INIS)

    Yaltkaya, S.

    2005-01-01

    Viscosity is one of the most important parameter in rheological and tribological properties of fluids. The objective of this study is to obtain the viscosity values from the simultaneous refractive-index measurements of lubricants, simply by dipping the fiber-optic probe into the oil to be measured. Due to the fact that these parameters are temperature dependent, within the interval under consideration, oil heated up steadily while measuring the viscosity and refractive index at the same time. The refractive index sensor, the digital viscometer and the thermometer were connected to a PC via an analog to digital converter and the values were acquired at the same time. The fiber optic refractive index sensor has been designed in our laboratory. By utilising Fresnel's fundamental reflection law, the intensity of reflected light from boundary surface (optic fiber core-motor oil) was measured at 660 nm wavelength and then refractive index of the oil was calculated. The derived refractive index values were converted viscosity values that acquired by using the calibration equation. The viscometer, used during the study, was the rotational Brookfield type

  3. Commentary Sex determination

    Indian Academy of Sciences (India)

    PRAKASH KUMAR G

    2008-01-31

    ZW is reserved for female heterogamety.) The Radder et al study used lab incubation regimes that mimic temperature profiles of cool natural nests, so temperature probably determines sex at least occasionally in nature.

  4. Determination of temperature dependence of full matrix material constants of PZT-8 piezoceramics using only one sample.

    Science.gov (United States)

    Zhang, Yang; Tang, Liguo; Tian, Hua; Wang, Jiyang; Cao, Wenwu; Zhang, Zhongwu

    2017-08-15

    Resonant ultrasound spectroscopy (RUS) was used to determine the temperature dependence of full matrix material constants of PZT-8 piezoceramics from room temperature to 100 °C. Property variations from sample to samples can be eliminated by using only one sample, so that data self-consistency can be guaranteed. The RUS measurement system error was estimated to be lower than 2.35%. The obtained full matrix material constants at different temperatures all have excellent self-consistency, which can help accurately predict device performance at high temperatures using finite element simulations.

  5. Determination of temperature dependency of material parameters for lead-free alkali niobate piezoceramics by the inverse method

    Directory of Open Access Journals (Sweden)

    K. Ogo

    2016-06-01

    Full Text Available Sodium potassium niobate (NKN piezoceramics have been paid much attention as lead-free piezoelectric materials in high temperature devices because of their high Curie temperature. The temperature dependency of their material parameters, however, has not been determined in detail up to now. For this purpose, we exploit the so-called Inverse Method denoting a simulation-based characterization approach. Compared with other characterization methods, the Inverse Method requires only one sample shape of the piezoceramic material and has further decisive advantages. The identification of material parameters showed that NKN is mechanically softer in shear direction compared with lead zirconate titanate (PZT at room temperature. The temperature dependency of the material parameters of NKN was evaluated in the temperature range from 30 °C to 150 °C. As a result, we figured out that dielectric constants and piezoelectric constants show a monotonous and isotropic increment with increasing temperature. On the other hand, elastic stiffness constant c 44 E of NKN significantly decreased in contrast to other elastic stiffness constants. It could be revealed that the decrement of c 44 E is associated with an orthorhombic-tetragonal phase transition. Furthermore, ratio of elastic compliance constants s 44 E / s 33 E exhibited similar temperature dependent behavior to the ratio of piezoelectric constants d15/d33. It is suspected that mechanical softness in shear direction is one origin of the large piezoelectric shear mode of NKN. Our results show that NKN are suitable for high temperature devices, and that the Inverse Method should be a helpful approach to characterize material parameters under their practical operating conditions for NKN.

  6. Determination of hydration numbers of electrolytes from temperature dependence of PMR chemical shifts

    International Nuclear Information System (INIS)

    Subramanian, N.

    1979-01-01

    The method proposed by Malinowski et al. for the determination of effective hydration numbers (h) of electrolytes leads to a consistent incrrease in the observed values of 'h' with increase in solution concentration. An attempt is made to rationalize the experimental results by cosidering the simultaneous effects of temperature and concentration on the proton chemical shift. It is suggested that Malinowski's technique might yeld 'h' values very close to the true value for those ions for which there is a fortuitous cancellation of structure-making and structure-breaking properties. (Author) [pt

  7. Drosophila mitotypes determine developmental time in a diet and temperature dependent manner.

    Science.gov (United States)

    Towarnicki, Samuel G; Ballard, J William O

    2017-07-01

    It is well known that specific mitochondrial (mt) DNA mutations can reduce organismal fitness and influence mitochondrial-nuclear interactions. However, determining specific mtDNA mutations that are beneficial has been elusive. In this study, we vary the diet and environmental temperature to study larval development time of two Drosophila melanogaster mitotypes (Alstonville and Dahomey), in two nuclear genetic backgrounds, and investigate developmental differences through weight, feeding rate, and movement. To manipulate the diet, we utilize the nutritional geometric framework to manipulate isocaloric diets of differing macronutrient ratios (1:2 and 1:16 protein: carbohydrate (P:C) ratios) and raise flies at three temperatures (19°C, 23°C and 27°C). Larvae with Dahomey mtDNA develop more slowly than Alstonville when fed the 1:2 P:C diet at all temperatures and developed more quickly when fed the 1:16 P:C diet at 23°C and 27°C. We determined that Dahomey larvae eat more, move less, and weigh more than Alstonville larvae when raised on the 1:16 P:C diet and that these physiological responses are modified by temperature. We suggest that 1 (or more) of 4 mtDNA changes is likely responsible for the observed effects and posit the mtDNA changes moderate a physiological trade-off between consumption and foraging. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A simple model for the determination of L0, D and τ in a semiconductor and their temperature dependence

    International Nuclear Information System (INIS)

    Ahmed, F.

    1989-07-01

    It is very important to characterize the quality of a semiconductor material before it is processed into a device. Diffusion length L 0 , diffusion constant D and carrier lifetime τ of minority carriers are some of the parameters which play a vital role in determining the quality of a semiconductor material. Recently Ahmed and co-workers have shown that by measuring the frequency response of a time varying (e iwt ) light (or electron) beam one can determine all the important parameters including the absorption coefficient of light and surface recombination velocity. Here we propose a simple method by which one can obtain L 0 , D and τ separately from measured phase shift of short circuit photo current at some modulation frequency ω and at two different wavelengths of incident light. It is suggested that the above procedure is particularly suitable for inferring the temperature dependence of these parameters. (author). 5 refs

  9. Transport characteristics of n-ZnO/p-Si heterojunction as determined from temperature dependent current–voltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Djiokap, S.R. Tankio, E-mail: stive.tankiodjiokap@nmmu.ac.za; Urgessa, Z.N.; Mbulanga, C.M.; Venter, A.; Botha, J.R.

    2016-01-01

    Zinc oxide (ZnO) nanorods have been synthesized by a two-step chemical bath deposition process on silicon substrates having different dopant densities and orientations. Scanning electron microscopy and X-ray diffraction analysis reveal that the orientation of the Si substrate does not affect the orientation, distribution or crystallinity of the nanostructures. The electrical properties of the ZnO/Si heterojunction are also investigated by current–voltage (I–V) measurements. The ideality factor is found to be 2.6 at 295 K, indicating that complex current transport mechanisms are at play. Temperature dependent I–V characteristics have been used to determine the dominant transport mechanism. The experimental results suggest that in the low bias region the current is dominated by a trap assisted multi-step tunneling process.

  10. A Review of Sex Determining Mechanisms in Geckos (Gekkota: Squamata)

    Science.gov (United States)

    Gamble, T.

    2010-01-01

    Geckos are a species-rich clade of reptiles possessing diverse sex determining mechanisms. Some species possess genetic sex determination, with both male and female heterogamety, while other species have temperature-dependent sex determination. I compiled information from the literature on the taxonomic distribution of these sex determining mechanisms in geckos. Using phylogenetic data from the literature, I reconstructed the minimum number of transitions among these sex determining mechanisms with parsimony-based ancestral state reconstruction. While only a small number of gecko species have been characterized, numerous changes among sex determining mechanisms were inferred. This diversity, coupled with the high frequency of transitions, makes geckos excellent candidates as a model clade for the study of vertebrate sex determination and evolution. PMID:20234154

  11. Sex determination in mythology and history.

    Science.gov (United States)

    Mittwoch, Ursula

    2005-02-01

    The history of ideas on how the sexes became divided spans at least three thousand years. The biblical account of the origin of Eve, and the opinions of the philosophers of classical Greece, have unexpected bearings on present-day ideas. The scientific study of sex determination can be said to have begun in the 17th century with the discovery of spermatozoa, but the origin and function of the "spermatic animalcules" eluded investigators until 1841. The mammalian egg was discovered in 1827, and in the last quarter of the century fertilization was observed. The view current at that time, that sex determination was under environmental control, gave way to the idea of chromosomal determination in the first quarter of the 20th century. The study of human and other mammalian chromosomes during the third quarter of the century, and the discovery of sex-chromosome abnormalities, emphasized the importance of the Y chromosome for male sex determination. The last quarter of the century witnessed a hunt for the "testis-determining" gene, thought to be responsible for the differentiation of Sertoli cells, and culminating in the isolation of SRY (Sry in the mouse). However, an increasing number of additional genes and growth factors were found to be required for the establishment of male sex. During the same period evidence emerged that male development was accompanied by enhanced growth, both of gonads and whole embryos. An unexpected finding was the demonstration of temperature-dependent sex determination in reptiles. With the advent of the 21st century, it was shown that Sry induces cell proliferation in fetal mouse gonads, and it has been suggested that male sex differentiation in mammals requires a higher metabolic rate. These insights could lead to a better understanding and improved treatment of abnormalities of sexual development.

  12. Temperature-dependent sex-reversal by a transformer-2 gene-edited mutation in the spotted wing drosophila, Drosophila suzukii

    Science.gov (United States)

    Female to male sex reversal was achieved in an emerging agricultural insect pest, Drosophila suzukii, by creating a temperature-sensitive point mutation in the sex-determination gene, transformer-2 (tra-2) using CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/ CRISPR-associated) hom...

  13. Temperature Dependence in Heterogeneous Nucleation with Application to the Direct Determination of Cluster Energy on Nearly Molecular Scale.

    Science.gov (United States)

    McGraw, Robert L; Winkler, Paul M; Wagner, Paul E

    2017-12-04

    A re-examination of measurements of heterogeneous nucleation of water vapor on silver nanoparticles is presented here using a model-free framework that derives the energy of critical cluster formation directly from measurements of nucleation probability. Temperature dependence is correlated with cluster stabilization by the nanoparticle seed and previously found cases of unusual increasing nucleation onset saturation ratio with increasing temperature are explained. A necessary condition for the unusual positive temperature dependence is identified, namely that the critical cluster be more stable, on a per molecule basis, than the bulk liquid to exhibit the effect. Temperature dependence is next examined in the classical Fletcher model, modified here to make the energy of cluster formation explicit in the model.  The contact angle used in the Fletcher model is identified as the microscopic contact angle, which can be directly obtained from heterogeneous nucleation experimental data by a recently developed analysis method. Here an equivalent condition, increasing contact angle with temperature, is found necessary for occurrence of unusual temperature dependence. Our findings have immediate applications to atmospheric particle formation and nanoparticle detection in condensation particle counters (CPCs).

  14. Transitions between sex-determining systems in reptiles and amphibians.

    Science.gov (United States)

    Sarre, Stephen D; Ezaz, Tariq; Georges, Arthur

    2011-01-01

    Important technological advances in genomics are driving a new understanding of the evolution of sex determination in vertebrates. In particular, comparative chromosome mapping in reptiles has shown an intriguing distribution of homology in sex chromosomes across reptile groups. When this new understanding is combined with the widespread distribution of genetic and temperature-dependent sex-determination mechanisms among reptiles, it is apparent that transitions between modes have occurred many times, as they have for amphibians (particularly between male and female heterogamety). It is also likely that thermosensitivity in sex determination is a key factor in those transitions in reptiles, and possibly in amphibians too. New models of sex determination involving temperature thresholds are providing the framework for the investigation of transitions and making possible key predictions about the homologies and sex-determination patterns expected among taxa in these groups. Molecular cytogenetics and other genomic approaches are essential to providing the fundamental material necessary to make advances in this field.

  15. Sex Determination, Sex Ratios, and Genetic Conflict

    NARCIS (Netherlands)

    Werren, John H.; Beukeboom, Leo W.

    1998-01-01

    Genetic mechanisms of sex determination are unexpectedly diverse and change rapidly during evolution. We review the role of genetic conflict as the driving force behind this diversity and turnover. Genetic conflict occurs when different components of a genetic system are subject to selection in

  16. Commentary Sex determination

    Indian Academy of Sciences (India)

    PRAKASH KUMAR G

    2008-01-31

    Jan 31, 2008 ... years old (Charnier 1966 reported it in an African agamid lizard), although it was ... people's attention in Susumu Ohno's now famous book on .... If they do enhance male and female fitness, sex chromosomes would then be.

  17. The evolution of sex ratios and sex-determining systems

    NARCIS (Netherlands)

    Uller, Tobias; Pen, Ido; Wapstra, Erik; Beukeboom, Leo W.; Komdeur, Jan

    Sex determination is a fundamental process governed by diverse mechanisms. Sex ratio selection is commonly implicated in the evolution of sex-determining systems, although formal models are rare. Here, we argue that, although sex ratio selection can induce shifts in sex determination, genomic

  18. Genotypic sex determination enabled adaptive radiations of extinct marine reptiles.

    Science.gov (United States)

    Organ, Chris L; Janes, Daniel E; Meade, Andrew; Pagel, Mark

    2009-09-17

    Adaptive radiations often follow the evolution of key traits, such as the origin of the amniotic egg and the subsequent radiation of terrestrial vertebrates. The mechanism by which a species determines the sex of its offspring has been linked to critical ecological and life-history traits but not to major adaptive radiations, in part because sex-determining mechanisms do not fossilize. Here we establish a previously unknown coevolutionary relationship in 94 amniote species between sex-determining mechanism and whether a species bears live young or lays eggs. We use that relationship to predict the sex-determining mechanism in three independent lineages of extinct Mesozoic marine reptiles (mosasaurs, sauropterygians and ichthyosaurs), each of which is known from fossils to have evolved live birth. Our results indicate that each lineage evolved genotypic sex determination before acquiring live birth. This enabled their pelagic radiations, where the relatively stable temperatures of the open ocean constrain temperature-dependent sex determination in amniote species. Freed from the need to move and nest on land, extreme physical adaptations to a pelagic lifestyle evolved in each group, such as the fluked tails, dorsal fins and wing-shaped limbs of ichthyosaurs. With the inclusion of ichthyosaurs, mosasaurs and sauropterygians, genotypic sex determination is present in all known fully pelagic amniote groups (sea snakes, sirenians and cetaceans), suggesting that this mode of sex determination and the subsequent evolution of live birth are key traits required for marine adaptive radiations in amniote lineages.

  19. An inelastic neutron scattering determination of the temperature dependence of the 3d-4f exchange interaction in Sm2Fe17

    International Nuclear Information System (INIS)

    Solodovnikov, Anton; Loewenhaupt, Michael; Moze, Oscar; Kuz'min, Michael D.; Bewley, Robert

    2002-01-01

    High energy transfer inelastic neutron scattering has been used to investigate the temperature dependence in the range from 20 to 450 K of the intermultiplet transition E inter in the intermetallic compound Sm 2 Fe 17 . The peak due to this transition, observed in the inelastic neutron spectrum, shifts to lower energies with increasing temperature. From the temperature dependence of E inter , the temperature dependence of the exchange field B ex acting on the Sm ion has been established experimentally, as the energy of the intermultiplet transition provides a direct value for the exchange field. At the highest measured temperature T=450 K, which is above the Curie point of 389 K for this compound, the transition energy is situated just above the bare spin-orbit splitting for Sm 3+ . The method utilized in the present investigation offers a rather easy and direct way to determine B ex in a large range of Sm intermetallics, which form an interesting class of hard magnetic materials

  20. Temperature dependent anomalous statistics

    International Nuclear Information System (INIS)

    Das, A.; Panda, S.

    1991-07-01

    We show that the anomalous statistics which arises in 2 + 1 dimensional Chern-Simons gauge theories can become temperature dependent in the most natural way. We analyze and show that a statistic's changing phase transition can happen in these theories only as T → ∞. (author). 14 refs

  1. Does the mechanism of sex determination constrain the potential for sex manipulation? A test in geckos with contrasting sex-determining systems

    Science.gov (United States)

    Kratochvíl, Lukáš; Kubička, Lukáš; Landová, Eva

    2008-03-01

    The concentration of yolk steroids was suggested to influence offspring gender in oviparous animals subject to both temperature-dependent sex determination (TSD) and genotypic sex determination (GSD). However, the proposed mechanisms of steroid effects are thought to differ between TSD and GSD: a direct effect of oestrogens on gonad feminisation in TSD species vs a differential induction of male-producing or female-producing gametes in GSD species. Geckos offer an ideal opportunity for testing these suggested mechanisms. Closely related gecko species differ in their modes of sex determination. They lay clutches of two synchronously formed eggs; both eggs share equal steroid levels. If identical hormonal composition and environment during vitellogenesis, gravidity and incubation determine the sex of the progeny, siblings should share the same gender in both TSD and GSD geckos. We found strong support for this prediction in a TSD gecko species. Among clutches that were incubated at the temperature that produced both sexes, there were no clutches with siblings of the opposite sex. On the other hand, about half of the clutches yielded siblings of the opposite sex in four GSD species. These results suggest that sex-determining systems constrain the ability of the female to produce single-sex siblings and, hence, it seems that the GSD mechanism constrains the opportunities for sex ratio manipulation in geckos via yolk steroid manipulation.

  2. Sex determination in the Hymenoptera

    NARCIS (Netherlands)

    Heimpel, George E.; de Boer, Jetske G.

    2008-01-01

    The dominant and ancestral mode of sex determination in the Hymenoptera is arrhenotokous parthenogenesis, in which diploid females develop from fertilized eggs and haploid males develop from unfertilized eggs. We discuss recent progress in the understanding of the genetic and cytoplasmic mechanisms

  3. Heritable Variation for Sex Ratio under Environmental Sex Determination in the Common Snapping Turtle (Chelydra Serpentina)

    Science.gov (United States)

    Janzen, F. J.

    1992-01-01

    The magnitude of quantitative genetic variation for primary sex ratio was measured in families extracted from a natural population of the common snapping turtle (Chelydra serpentina), which possesses temperature-dependent sex determination (TSD). Eggs were incubated at three temperatures that produced mixed sex ratios. This experimental design provided estimates of the heritability of sex ratio in multiple environments and a test of the hypothesis that genotype X environment (G X E) interactions may be maintaining genetic variation for sex ratio in this population of C. serpentina. Substantial quantitative genetic variation for primary sex ratio was detected in all experimental treatments. These results in conjunction with the occurrence of TSD in this species provide support for three critical assumptions of Fisher's theory for the microevolution of sex ratio. There were statistically significant effects of family and incubation temperature on sex ratio, but no significant interaction was observed. Estimates of the genetic correlations of sex ratio across environments were highly positive and essentially indistinguishable from +1. These latter two findings suggest that G X E interaction is not the mechanism maintaining genetic variation for sex ratio in this system. Finally, although substantial heritable variation exists for primary sex ratio of C. serpentina under constant temperatures, estimates of the effective heritability of primary sex ratio in nature are approximately an order of magnitude smaller. Small effective heritability and a long generation time in C. serpentina imply that evolution of sex ratios would be slow even in response to strong selection by, among other potential agents, any rapid and/or substantial shifts in local temperatures, including those produced by changes in the global climate. PMID:1592234

  4. Genetic sex determination and extinction.

    Science.gov (United States)

    Hedrick, Philip W; Gadau, Jürgen; Page, Robert E

    2006-02-01

    Genetic factors can affect the probability of extinction either by increasing the effect of detrimental variants or by decreasing the potential for future adaptive responses. In a recent paper, Zayed and Packer demonstrate that low variation at a specific locus, the complementary sex determination (csd) locus in Hymenoptera (ants, bees and wasps), can result in a sharply increased probability of extinction. Their findings illustrate situations in which there is a feedback process between decreased genetic variation at the csd locus owing to genetic drift and decreased population growth, resulting in an extreme type of extinction vortex for these ecologically important organisms.

  5. Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects.

    Science.gov (United States)

    Blackmon, Heath; Ross, Laura; Bachtrog, Doris

    2017-01-01

    Insects harbor a tremendous diversity of sex determining mechanisms both within and between groups. For example, in some orders such as Hymenoptera, all members are haplodiploid, whereas Diptera contain species with homomorphic as well as male and female heterogametic sex chromosome systems or paternal genome elimination. We have established a large database on karyotypes and sex chromosomes in insects, containing information on over 13000 species covering 29 orders of insects. This database constitutes a unique starting point to report phylogenetic patterns on the distribution of sex determination mechanisms, sex chromosomes, and karyotypes among insects and allows us to test general theories on the evolutionary dynamics of karyotypes, sex chromosomes, and sex determination systems in a comparative framework. Phylogenetic analysis reveals that male heterogamety is the ancestral mode of sex determination in insects, and transitions to female heterogamety are extremely rare. Many insect orders harbor species with complex sex chromosomes, and gains and losses of the sex-limited chromosome are frequent in some groups. Haplodiploidy originated several times within insects, and parthenogenesis is rare but evolves frequently. Providing a single source to electronically access data previously distributed among more than 500 articles and books will not only accelerate analyses of the assembled data, but also provide a unique resource to guide research on which taxa are likely to be informative to address specific questions, for example, for genome sequencing projects or large-scale comparative studies. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. SEX DETERMINATION FROM FEMORAL HEAD DIAMETERS IN ...

    African Journals Online (AJOL)

    hi-tech

    2000-03-01

    Mar 1, 2000 ... In medico-legal cases where sophisticated methods of sex determination is lacking, these ... scientific methods(3). Using the visual method ... between the sexes and the values of the right and left femoral head diameters.

  7. Sex selection and restricting abortion and sex determination.

    Science.gov (United States)

    Zilberberg, Julie

    2007-11-01

    Sex selection in India and China is fostered by a limiting social structure that disallows women from performing the roles that men perform, and relegates women to a lower status level. Individual parents and individual families benefit concretely from having a son born into the family, while society, and girls and women as a group, are harmed by the widespread practice of sex selection. Sex selection reinforces oppression of women and girls. Sex selection is best addressed by ameliorating the situations of women and girls, increasing their autonomy, and elevating their status in society. One might argue that restricting or prohibiting abortion, prohibiting sex selection, and prohibiting sex determination would eliminate sex selective abortion. But this decreases women's autonomy rather than increases it. Such practices will turn underground. Sex selective infanticide, and slower death by long term neglect, could increase. If abortion is restricted, the burden is placed on women seeking abortions to show that they have a legally acceptable or legitimate reason for a desired abortion, and this seriously limits women's autonomy. Instead of restricting abortion, banning sex selection, and sex determination, it is better to address the practice of sex selection by elevating the status of women and empowering women so that giving birth to a girl is a real and positive option, instead of a detriment to the parents and family as it is currently. But, if a ban on sex selective abortion or a ban on sex determination is indeed instituted, then wider social change promoting women's status in society should be instituted simultaneously.

  8. Temperature dependence of plastic scintillators

    Science.gov (United States)

    Peralta, L.

    2018-03-01

    Plastic scintillator detectors have been studied as dosimeters, since they provide a cost-effective alternative to conventional ionization chambers. Several articles have reported undesired response dependencies on beam energy and temperature, which provides the motivation to determine appropriate correction factors. In this work, we studied the light yield temperature dependency of four plastic scintillators, BCF-10, BCF-60, BC-404, RP-200A and two clear fibers, BCF-98 and SK-80. Measurements were made using a 50 kVp X-ray beam to produce the scintillation and/or radioluminescence signal. The 0 to 40 °C temperature range was scanned for each scintillator, and temperature coefficients were obtained.

  9. Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering

    OpenAIRE

    Yanli Liu; Xifeng Yang; Dunjun Chen; Hai Lu; Rong Zhang; Youdou Zheng

    2015-01-01

    The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV) near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO) phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with th...

  10. Microbial manipulation of host sex determination

    NARCIS (Netherlands)

    Beukeboom, Leo W.

    A recent study in the lepidopteran Ostrinia scapulalis shows that endosymbionts can actively manipulate the sex determination mechanism of their host. Wolbachia bacteria alter the sex-specific splicing of the doublesex master switch gene. In ZZ males of this female heterogametic system, the female

  11. Occupational Segregation by Sex: Determinants and Changes.

    Science.gov (United States)

    Beller, Andrea H.

    1982-01-01

    This study found that occupational sex segregation began to diminish during the 1970s, in conjunction with enforcement of the equal employment opportunity laws against sex discrimination in employment. The success of these laws suggests that discrimination was originally a determinant of occupational segregation. (Author/SK)

  12. Using Check-All-That-Apply (CATA) method for determining product temperature-dependent sensory-attribute variations: A case study of cooked rice.

    Science.gov (United States)

    Pramudya, Ragita C; Seo, Han-Seok

    2018-03-01

    Temperatures of most hot or cold meal items change over the period of consumption, possibly influencing sensory perception of those items. Unlike temporal variations in sensory attributes, product temperature-induced variations have not received much attention. Using a Check-All-That-Apply (CATA) method, this study aimed to characterize variations in sensory attributes over a wide range of temperatures at which hot or cold foods and beverages may be consumed. Cooked milled rice, typically consumed at temperatures between 70 and 30°C in many rice-eating countries, was used as a target sample in this study. Two brands of long-grain milled rice were cooked and randomly presented at 70, 60, 50, 40, and 30°C. Thirty-five CATA terms for cooked milled rice were generated. Eighty-eight untrained panelists were asked to quickly select all the CATA terms that they considered appropriate to characterize sensory attributes of cooked rice samples presented at each temperature. Proportions of selection by panelists for 13 attributes significantly differed among the five temperature conditions. "Product temperature-dependent sensory-attribute variations" differed with two brands of milled rice grains. Such variations in sensory attributes, resulted from both product temperature and rice brand, were more pronounced among panelists who more frequently consumed rice. In conclusion, the CATA method can be useful for characterizing "product temperature-dependent sensory attribute variations" in cooked milled-rice samples. Further study is needed to examine whether the CATA method is also effective in capturing "product temperature-dependent sensory-attribute variations" in other hot or cold foods and beverages. Published by Elsevier Ltd.

  13. Sex determination: insights from the silkworm

    Indian Academy of Sciences (India)

    2010-09-06

    determination pathway that controls most sex-specific phenotypes, is a .... Sports and Culture, Government of Japan, grant-in-aid for Young. Scientists ... Berghammer A. J., Klingler M. and Wimmer E. A. 1999 A universal marker for ...

  14. Sex determination: ways to evolve a hermaphrodite.

    OpenAIRE

    Braendle , Christian; Félix , Marie-Anne

    2006-01-01

    Most species of the nematode genus Caenorhabditis reproduce through males and females; C. elegans and C. briggsae, however, produce self-fertile hermaphrodites instead of females. These transitions to hermaphroditism evolved convergently through distinct modifications of germline sex determination mechanisms.

  15. Temperature dependence of surface nanobubbles

    NARCIS (Netherlands)

    Berkelaar, R.P.; Seddon, James Richard Thorley; Zandvliet, Henricus J.W.; Lohse, Detlef

    2012-01-01

    The temperature dependence of nanobubbles was investigated experimentally using atomic force microscopy. By scanning the same area of the surface at temperatures from 51 °C to 25 °C it was possible to track geometrical changes of individual nanobubbles as the temperature was decreased.

  16. Determination of sex by armbone dimensions.

    Science.gov (United States)

    Aye, Victor Omakoji

    2010-06-15

    Sex determination is a vital part of the medico-legal system but can be difficult in cases where the body is damaged. The purpose of this study was to develop a technique for sex determination from three arm-bone dimensions (wrist circumference, arm length and arm span). This knowledge can be applied in cases of mass disaster, homicide and events such as sports. Data were collected for 95 Nigerian male students and 90 Nigerian female students using physical anthropometry. Discriminant function presented the wrist dimension as the dominant contributor in this study. Combination equations for both the wrist and arm-span dimensions correctly classified sex (male/female) with an accuracy rate of 84.9%. On cross-validation, sex was also established with the same 84.9% accuracy rate. Sex determination was higher in males. Sexual dimorphism was established in this study, although the wrist circumference was more distinct than arm span; a combination of both generated sex with an accuracy prediction rate of 84.9%. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  17. Longevity enhances selection of environmental sex determination.

    Science.gov (United States)

    Bull, J J; Bulmer, M G

    1989-12-01

    Environmental sex determination (ESD) is a mechanism in which an individual develops as male or female largely in response to some environmental effect experienced early in life. Its forms range from sex determination by egg incubation temperature in reptiles to sex determination of photoperiod in amphipods. Previous theoretical work as suggested that ESD is favored by natural selection if the fitness consequences of the early environmental experience differ for males and females, so that an individual benefits by being male under some conditions and female under others. A drawback of ESD is that it enables climatic changes to influence the population sex ratio, and such fluctuations select against ESD. This study employed numerical analyses to investigate the balance between these two opposing forces. The negative impact of climatic fluctuations appears to depend greatly on species longevity: substantial between-year fluctuations are of little consequence in selecting against ESD in long-lived species because annual sex ratio fluctuations tend to cancel and thus alter the total population sex ratio only slightly. Thus, if a species is sufficiently long-lived, extreme ESD can be maintained despite only a weak advantage. This result offers one explanation for the failure to demonstrate an advantage for the extreme forms of ESD observed in reptiles.

  18. Transport characteristics of Pd Schottky barrier diodes on epitaxial n-GaSb as determined from temperature dependent current–voltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Venter, A., E-mail: andre.venter@nmmu.ac.za [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Murape, D.M.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Auret, F.D. [Department of Physics, University of the Pretoria, Lynnwood Road, Pretoria 0002 (South Africa)

    2015-01-01

    The temperature dependent transport characteristics of Pd/n-GaSb:Te Schottky contacts with low and saturating reverse current are investigated by means of current–voltage measurements between 80 K and 320 K. The apparent barrier height and ideality factor increase with a decrease in temperature. Neither thermionic nor thermionic field emission can explain the low temperature characteristics of these diodes. Instead, evidence is presented for barrier inhomogeneity across the metal/semiconductor contact. A plot of the barrier height, ϕ{sub b} vs. 1/2kT revealed a double Gaussian distribution for the barrier height with ϕ{sub b,mean} assuming values of 0.59 eV ± 0.07 (80–140 K) and 0.25 eV ± 0.12 (140–320 K) respectively. - Highlights: • Transport characteristics of Pd/epitaxial n-GaSb:Te SBDs are studied by means of I-V-T measurements. • SBDs have remarkably low and saturating reverse current – of the lowest ever reported for GaSb. • Transport behaviour is explained by considering electronic states present on the GaSb surface. • Evidence is presented for barrier inhomogeneity across the metal-semiconductor contact.

  19. Transport characteristics of Pd Schottky barrier diodes on epitaxial n-GaSb as determined from temperature dependent current–voltage measurements

    International Nuclear Information System (INIS)

    Venter, A.; Murape, D.M.; Botha, J.R.; Auret, F.D.

    2015-01-01

    The temperature dependent transport characteristics of Pd/n-GaSb:Te Schottky contacts with low and saturating reverse current are investigated by means of current–voltage measurements between 80 K and 320 K. The apparent barrier height and ideality factor increase with a decrease in temperature. Neither thermionic nor thermionic field emission can explain the low temperature characteristics of these diodes. Instead, evidence is presented for barrier inhomogeneity across the metal/semiconductor contact. A plot of the barrier height, ϕ b vs. 1/2kT revealed a double Gaussian distribution for the barrier height with ϕ b,mean assuming values of 0.59 eV ± 0.07 (80–140 K) and 0.25 eV ± 0.12 (140–320 K) respectively. - Highlights: • Transport characteristics of Pd/epitaxial n-GaSb:Te SBDs are studied by means of I-V-T measurements. • SBDs have remarkably low and saturating reverse current – of the lowest ever reported for GaSb. • Transport behaviour is explained by considering electronic states present on the GaSb surface. • Evidence is presented for barrier inhomogeneity across the metal-semiconductor contact

  20. Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering

    Directory of Open Access Journals (Sweden)

    Yanli Liu

    2015-01-01

    Full Text Available The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with the theoretical calculation result, taking lattice mismatch and thermal mismatch into account together. This good agreement indicates that the UV near-resonant Raman scattering can be a direct and effective method to characterize the stress state in thin AlGaN barrier layer of AlGaN/GaN HEMT heterostructures.

  1. Temperature dependence of Brewster's angle.

    Science.gov (United States)

    Guo, Wei

    2018-01-01

    In this work, a dielectric at a finite temperature is modeled as an ensemble of identical atoms moving randomly around where they are trapped. Light reflection from the dielectric is then discussed in terms of atomic radiation. Specific calculation demonstrates that because of the atoms' thermal motion, Brewster's angle is, in principle, temperature-dependent, and the dependence is weak in the low-temperature limit. What is also found is that the Brewster's angle is nothing but a result of destructive superposition of electromagnetic radiation from the atoms.

  2. How is sex determined in insects?

    Indian Academy of Sciences (India)

    gan's student Calvin Bridges formulated his classic balance theory of sex determination in ... affect not only specific traits but also the entire sexual fate of an individual. ... the decision whether to become male or female is conveyed very early in ...

  3. The accuracy of 2D ultrasound prenatal sex determination ...

    African Journals Online (AJOL)

    Most of the women were happy even when the sex differed from that which they desired. Conclusion: Prenatal sonographic sex determination has a high sensitivity index. Consequently we advocate its use prior to more invasive sex tests. Keywords: Accuracy, gender determination, prenatal gender, prenatal sex, sex ...

  4. Sex Determination by Morphometry of Lips

    Directory of Open Access Journals (Sweden)

    B. Senthil Kumar

    2018-04-01

    Full Text Available Background: Facial anthropometric parameters are affected by various factors including age, sex, ethnicity, socioeconomic status, environment and region. The lips become thinner as age increases and the wet line moves caudally, in addition oral commissure begins to downturn. Aim and Objectives: The purpose of this study was to create a baseline data in determining the sex of the people from India and Malaysia depending on morphometry of lips. Materials and Methods:Atotal of 100 Malaysians and 100 South Indians were enrolled for the study. Various morphometric measurements of lips were taken using Vernier caliper. The data were analyzed by one way ANOVAto find out the significance among the sex and population. Results: All the measurements of upper and lower lips were higher in males as compared to females and thus sexual dimorphism exists. Mouth width and height were found to be more in Indian males followed by Malaysian males whereas in females it's vice versa. Vermilion upper lip occupied less than half of total upper lip height, whereas vermilion lower lip occupied more than half of total lower lip height in both the population. Indian males and females differed significantly in lip parameters from those of Malaysian males and females. Conclusion: It can be concluded from the study that same standards cannot be used on each other's populations for identification and cosmetic surgery. The study highlights the applied significance of observations to forensic medicine namely, personal identification, racial and sex dimorphic criteria of identification.

  5. Genetics of sex determination in the haplodiploid wasp Nasonia ...

    Indian Academy of Sciences (India)

    2010-09-06

    Sep 6, 2010 ... How gender is determined under haplodiploidy in the ab- sence of heteromorphic sex ... determination (see below). Sex-determination mutants ... not others (Nöthiger and Steinmann-Zwicky 1985; Wilkins. 1995; Saccone et al.

  6. Differentiation of sex chromosomes and karyotypic evolution in the eye-lid geckos (Squamata: Gekkota: Eublepharidae), a group with different modes of sex determination.

    Science.gov (United States)

    Pokorná, Martina; Rábová, Marie; Ráb, Petr; Ferguson-Smith, Malcolm A; Rens, Willem; Kratochvíl, Lukáš

    2010-11-01

    The eyelid geckos (family Eublepharidae) include both species with temperature-dependent sex determination and species where genotypic sex determination (GSD) was suggested based on the observation of equal sex ratios at several incubation temperatures. In this study, we present data on karyotypes and chromosomal characteristics in 12 species (Aeluroscalabotes felinus, Coleonyx brevis, Coleonyx elegans, Coleonyx variegatus, Eublepharis angramainyu, Eublepharis macularius, Goniurosaurus araneus, Goniurosaurus lichtenfelderi, Goniurosaurus luii, Goniurosaurus splendens, Hemitheconyx caudicinctus, and Holodactylus africanus) covering all genera of the family, and search for the presence of heteromorphic sex chromosomes. Phylogenetic mapping of chromosomal changes showed a long evolutionary stasis of karyotypes with all acrocentric chromosomes followed by numerous chromosomal rearrangements in the ancestors of two lineages. We have found heteromorphic sex chromosomes in only one species, which suggests that sex chromosomes in most GSD species of the eyelid geckos are not morphologically differentiated. The sexual difference in karyotype was detected only in C. elegans which has a multiple sex chromosome system (X(1)X(2)Y). The metacentric Y chromosome evolved most likely via centric fusion of two acrocentric chromosomes involving loss of interstitial telomeric sequences. We conclude that the eyelid geckos exhibit diversity in sex determination ranging from the absence of any sexual differences to heteromorphic sex chromosomes, which makes them an interesting system for exploring the evolutionary origin of sexually dimorphic genomes.

  7. Sex ratio variation and sex determination in Urtica dioica

    NARCIS (Netherlands)

    Glawe, Grit Anja

    2006-01-01

    This thesis will first document on variation in progeny sex ratios among individual female plants of Urtica dioica at our field site in Meijendel (Chapter 2). Next, we show that there is also considerable sex ratio variation among male and female flowering shoots in 26 natural populations studied

  8. Sex differences in adolescent depression: do sex hormones determine vulnerability?

    NARCIS (Netherlands)

    Naninck, E.F.G.; Lucassen, P.J.; Bakker, J.

    2011-01-01

    Depression is one of the most common, costly and severe psychopathologies worldwide. Its incidence, however, differs significantly between the sexes, and depression rates in women are twice those of men. Interestingly, this sex difference emerges during adolescence. Although the adolescent period is

  9. Determination of temperature-dependent thermal conductivity of a BaSnO{sub 3−δ} single crystal by using the 3ω method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Joon; Kim, Tai Hoon; Lee, Woong-Jhae; Chai, Yisheng; Kim, Jae Wook; Jwa, Yeon Jae; Chung, Sukhwan; Kim, Seon Joong; Sohn, Egon [Center for Novel States of Complex Materials Research, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Lee, Seung Min [Hanbeam Corporation Ltd, Iui-dong 906-5, Yeongtong-gu, Suwon-si, Gyeonggi-do (Korea, Republic of); Choi, Ki-Young [Center for Novel States of Complex Materials Research, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Kim, Kee Hoon, E-mail: khkim@phya.snu.ac.kr [Center for Novel States of Complex Materials Research, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2014-06-01

    Highlights: • This is the first report about thermal conductivity of BaSnO{sub 3−δ} single crystals. • We report the successful κ measurement of the crystals by employing the 3ω method. • The BaSnO{sub 3−δ} single crystal can be a good perovskite substrate with high κ. • We found that phonons mainly contribute to the heat transport in BaSnO{sub 3−δ}. - Abstract: The single crystal of the electron doped BaSnO{sub 3−δ} system has been recently found to have high electrical mobility (up to 320 cm{sup 2} V{sup −1} s{sup −1}) at room temperature and excellent oxygen stability. Although thermal conductivity (κ) of the BaSnO{sub 3−δ} single crystal is an important physical quantity, the κ measurement by the conventional DC method has been difficult due to the limited crystal size. Herein, we report the first measurement of κ by using the 3ω method from ∼20 to 300 K in the oxygen deficient BaSnO{sub 3−δ} single crystal with carrier concentration of ∼10{sup 18} cm{sup −3}. We found that κ is proportional to T{sup −1} above 50 K, indicating that phonons mainly contribute to the heat transport. Moreover, the electronic contribution is determined as ∼4% of the measured κ from the Wiedemann–Franz law. The κ value is 0.132 W cm{sup −1} K{sup −1} at room temperature and is increased progressively at lower temperatures, becoming overall larger than that of the SrTiO{sub 3} single crystal. Our results thus point out that BaSnO{sub 3−δ} can be a good substrate for growing transparent electronic thin films with the perovskite structure.

  10. Guardian small RNAs and sex determination.

    Science.gov (United States)

    Katsuma, Susumu; Kawamoto, Munetaka; Kiuchi, Takashi

    2014-01-01

    The W chromosome of the silkworm Bombyx mori has been known to determine femaleness for more than 80 years. However, the feminizing gene has not been molecularly identified, because the B. mori W chromosome is almost fully occupied by a large number of transposable elements. The W chromosome-derived feminizing factor of B. mori was recently shown to be a female-specific PIWI-interacting RNA (piRNA). piRNAs are small RNAs that potentially repress invading "non-self" elements (e.g., transposons and virus-like elements) by associating with PIWI proteins. Our results revealed that female-specific piRNA precursors, which we named Fem, are transcribed from the sex-determining region of the W chromosome at the early embryonic stage and are processed into a single mature piRNA (Fem piRNA). Fem piRNA forms a complex with Siwi (silkworm Piwi), which cleaves a protein-coding mRNA transcribed from the Z chromosome. RNA interference of this Z-linked gene, which we named Masc, revealed that this gene encodes a protein required for masculinization and dosage compensation. Fem and Masc both participate in the ping-pong cycle of the piRNA amplification loop by associating with the 2 B. mori PIWI proteins Siwi and BmAgo3 (silkworm Ago3), respectively, indicating that the piRNA-mediated interaction between the 2 sex chromosomes is the primary signal for the B. mori sex determination cascade. Fem is a non-transposable repetitive sequence on the W chromosome, whereas Masc is a single-copy protein-coding gene. It is of great interest how the piRNA system recognizes "self "Masc mRNA as "non-self" RNA.

  11. The sex and sex determination in Pyropia haitanensis (Bangiales, Rhodophyta).

    Science.gov (United States)

    Zhang, Yuan; Yan, Xing-hong; Aruga, Yusho

    2013-01-01

    Pyropia haitanensis has a biphasic life cycle with macroscopic gametophytic blade (n) and microscopic filamentous conchocelis (2n) phase. Its gametophytic blades have long been believed to be mainly dioecious. However, when crossing the red mutant (R, ♀) with the wild type (W, ♂), the parental colors were segregated in F1 blades, of which 96.1% were linearly sectored with 2-4 color sectors. When color sectors were excised from the color-sectored blades and cultured singly, 99.7% of the color sectors appeared to be unisexual with an equal sex ratio. Although the sex of color sector did not genetically link with its color, the boundaries of both sex and color sectors coincided precisely. About 87.9% of the examined color-sectored blades were monoecious and the percentage increased with the number of color sectors of a blade. The gametophytic blades from each conchocelis strain produced by parthenogenesis of the excised color sectors were unisexual and unicolor, showing the same sex and color as their original sectors. These results indicate that most of the sexually reproduced Py. haitanensis blades are monoecious, and their sex is controlled by segregation of a pair of alleles during meiosis of conchospore, forming a sex-sectored tetrad. During the subsequent development of blades, one or two lower cell(s) of the tetrad contribute mainly to rhizoid formation, and rarely show their sexual phenotype, leading to reduced frequency of full sex phenotype of the meiotic blades. Moreover, the aberrant segregations of sex genes or color genes in a few of F1 blades were probably due to gene conversions, but there was no sex transfer in Py. haitanensis.

  12. [Elucidation of key genes in sex determination in genetics teaching].

    Science.gov (United States)

    Li, Meng; He, Zhumei

    2014-06-01

    Sex is an important and complex feature of organisms, which is controlled by the genetic and environmental factors. The genetic factors, i.e., genes, are vital in sex determination. However, not all the related genes play the same roles, and some key genes play a vital role in the sex determination and differentiation. With the development of the modern genetics, a great progress on the key genes has been made in sex determination. In this review, we summarize the mechanism of sex determination and the strategy of how to study the key genes in sex determination. It will help us to understand the mechanism of sex determination better in the teaching of genetics.

  13. Temperature dependence of elastic properties of paratellurite

    International Nuclear Information System (INIS)

    Silvestrova, I.M.; Pisarevskii, Y.V.; Senyushenkov, P.A.; Krupny, A.I.

    1987-01-01

    New data are presented on the temperature dependence of the elastic wave velocities, elastic stiffness constants, and thermal expansion of paratellurite. It is shown that the external pressure appreciably influences the elastic properties of TeO 2 , especially the temperature dependence of the elastic modulus connected with the crystal soft mode. (author)

  14. Conflict over condition-dependent sex allocation can lead to mixed sex-determination systems

    NARCIS (Netherlands)

    Kuijper, Bram; Pen, Ido

    Theory suggests that genetic conflicts drive turnovers between sex-determining mechanisms, yet these studies only apply to cases where sex allocation is independent of environment or condition. Here, we model parent-offspring conflict in the presence of condition-dependent sex allocation, where the

  15. Sex ratio selection and multi-factorial sex determination in the housefly : A dynamic model

    NARCIS (Netherlands)

    Kozielska, M.A.; Pen, I.R.; Beukeboom, L.W.; Weissing, F.J.

    Sex determining (SD) mechanisms are highly variable between different taxonomic groups and appear to change relatively quickly during evolution. Sex ratio selection could be a dominant force causing such changes. We investigate theoretically the effect of sex ratio selection on the dynamics of a

  16. Conflict over condition-dependent sex allocation can lead to mixed sex-determination systems

    NARCIS (Netherlands)

    Kuijper, Bram; Pen, Ido

    2014-01-01

    Theory suggests that genetic conflicts drive turnovers between sex-determining mechanisms, yet these studies only apply to cases where sex allocation is independent of environment or condition. Here, we model parent-offspring conflict in the presence of condition-dependent sex allocation, where the

  17. Sex Determination: Why So Many Ways of Doing It?

    Science.gov (United States)

    Bachtrog, Doris; Mank, Judith E.; Peichel, Catherine L.; Kirkpatrick, Mark; Otto, Sarah P.; Ashman, Tia-Lynn; Hahn, Matthew W.; Kitano, Jun; Mayrose, Itay; Ming, Ray; Perrin, Nicolas; Ross, Laura; Valenzuela, Nicole; Vamosi, Jana C.

    2014-01-01

    Sexual reproduction is an ancient feature of life on earth, and the familiar X and Y chromosomes in humans and other model species have led to the impression that sex determination mechanisms are old and conserved. In fact, males and females are determined by diverse mechanisms that evolve rapidly in many taxa. Yet this diversity in primary sex-determining signals is coupled with conserved molecular pathways that trigger male or female development. Conflicting selection on different parts of the genome and on the two sexes may drive many of these transitions, but few systems with rapid turnover of sex determination mechanisms have been rigorously studied. Here we survey our current understanding of how and why sex determination evolves in animals and plants and identify important gaps in our knowledge that present exciting research opportunities to characterize the evolutionary forces and molecular pathways underlying the evolution of sex determination. PMID:24983465

  18. Determining sex ratios of turtle hatchlings

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Previous status assessments of marine turtles have assumed that the natural sex ratio of a marine turtle population is 1:1 (e.g. Conant et al. 2009). However, this...

  19. Sex-determination systems and their evolution: Mammals

    International Nuclear Information System (INIS)

    Colorado Garzon, Fredy A; Matta Camacho, Nubia E; Sanchez, Antonio

    2012-01-01

    Sex-determination methods are very diverse as they have become an enduring research field, understanding the causes of gonadal development and elucidating the main factors involved in sex-determination of offspring required relating information from far-ranging areas such as cytology, embryology, morphology, molecular biology and even ecology and evolution. This article presents an overview of sex-determination in placental mammals, encompassing several levels of biological organization. The importance of the underlying molecular tools in the context of sex-determination assays and their implications in conservation genetics is also discussed.

  20. Personal identification and sex determination using cheiloscopy

    Directory of Open Access Journals (Sweden)

    Ravindra Naik Gugulothu

    2015-01-01

    Full Text Available Introduction: Identification of an individual is a prerequisite for certification of death and for personal, social, and legal reasons. The study of lip prints (cheiloscopy was thought of as a method of identification of a person. It is safe to assume that cheiloscopy, in its present stage of development, has become a means of criminal identification dealing with lip prints. Aims and Objectives: To evaluate the lip prints of different individuals in various parts of the lip, to find out the incidence of any particular pattern in relation to specific gender, to ascertain the authenticity of lip prints as a tool for identification of an individual and establish its evidentiary value. Materials and Methods: The study was conducted on 500 subjects, which included 250 males (4 twins and 250 females, in the age group of 18-30 years. After application of lipstick evenly, the lip print of each subject was obtained on a simple bond paper. The lip prints of each individual were scanned using an image scanner set at a resolution of 600 dpi for better interpretation. Results: We had correctly matched the gender of 487 individuals out of 500 samples taken. We also found that no lip prints were similar among the 500 subjects and even in twins. Interpretation and Conclusion: Along with other traditional methods, cheiloscopy can also serve as a very important tool in the identification of a person based on the characteristic arrangement of lines and grooves appearing on the red portion of the lips. It can be used for sex determination and personal identification for forensic purposes.

  1. Temperature dependence of nuclear surface properties

    International Nuclear Information System (INIS)

    Campi, X.; Stringari, S.

    1982-01-01

    Thermal properties of nuclear surface are investigated in a semi-infinite medium. Explicit analytical expression are given for the temperature dependence of surface thickness, surface energy and surface free energy. In this model the temperature effects depend critically on the nuclear incompressibility and on the shape of the effective mass at the surface. To illustrate the relevance of these effects we made an estimate of the temperature dependence of the fission barrier height. (orig.)

  2. Evaluation of temperature dependent neutron resonance integrals

    International Nuclear Information System (INIS)

    Menon, S.V.G.; Sahni, D.C.

    1975-01-01

    The Fourier transform method is extended for evaluating temperature dependent resonance integrals and Doppler coefficients. With the temperature dependent cross-sections, the slowing-down equation is transformed into a Fredholm integral equation of second kind. A method of solution is presented using the familiar Gauss-Hermite quadrature formulae. As a byproduct of the above technique, a fast and accurate method for computing the resonance integral J-function is given. (orig.) [de

  3. Sex determination: ciliates' self-censorship.

    Science.gov (United States)

    Bloomfield, Gareth

    2014-07-07

    Differentiation involves the expression of certain latent cellular characteristics and the repression of others. A new study has revealed how Paramecium uses short RNAs to delete information from the somatic genome of one of its two sexes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Sex determination of baleen whale artefacts

    DEFF Research Database (Denmark)

    Sinding, Mikkel Holger Strander; Tervo, Outi M.; Grønnow, Bjarne

    2016-01-01

    to 4500 years old bowhead whale samples, and for comparison on dilution series from modern bowhead whales of known sex. DNA sequencing of PCR products obtained from the ancient material confirmed a higher proportion of successful PCR amplifications of the X homologue over the Y homologue. This potentially...

  5. Sex Determination from Fingerprint Ridge Density | Gungadin ...

    African Journals Online (AJOL)

    This study was conducted with an aim to establish a relationship between sex and fingerprint ridge density. The fingerprints were taken from 500 subjects (250 males and 250 females) in the age group of 18-60 years. After taking fingerprints, the ridges were counted in the upper portion of the radial border of each print for all ...

  6. Climate-driven population divergence in sex-determining systems

    NARCIS (Netherlands)

    Pen, Ido; Uller, Tobias; Feldmeyer, Barbara; Harts, Anna; While, Geoffrey M.; Wapstra, Erik

    2010-01-01

    Sex determination is a fundamental biological process, yet its mechanisms are remarkably diverse(1,2). In vertebrates, sex can be determined by inherited genetic factors or by the temperature experienced during embryonic development(2,3). However, the evolutionary causes of this diversity remain

  7. Single locus complementary sex determination in Hymenoptera : an "unintelligent" design?

    NARCIS (Netherlands)

    Wilgenburg, Ellen van; Driessen, Gerard; Beukeboom, Leo W.

    2006-01-01

    The haplodiploid sex determining mechanism in Hymenoptera (males are haploid, females are diploid) has played an important role in the evolution of this insect order. In Hymenoptera sex is usually determined by a single locus, heterozygotes are female and hemizygotes are male. Under inbreeding,

  8. Single locus complementary sex determination in Hymenoptera: an "unintelligent" design?

    NARCIS (Netherlands)

    van Wilgenburg, E.; Driessen, G.J.J.; Beukeboom, L.W.

    2006-01-01

    The haplodiploid sex determining mechanism in Hymenoptera (males are haploid, females are diploid) has played an important role in the evolution of this insect order. In Hymenoptera sex is usually determined by a single locus, heterozygotes are female and hemizygotes are male. Under inbreeding,

  9. Insect sex determination : It all evolves around transformer

    NARCIS (Netherlands)

    Verhulst, Eveline C.; van de Zande, Louis; Beukeboom, Leo W.

    Insects exhibit a variety of sex determining mechanisms including male or female heterogamety and haplodiploidy. The primary signal that starts sex determination is processed by a cascade of genes ending with the conserved switch doublesex that controls sexual differentiation. Transformer is the

  10. Insect sex determination: it all evolves around transformer.

    Science.gov (United States)

    Verhulst, Eveline C; van de Zande, Louis; Beukeboom, Leo W

    2010-08-01

    Insects exhibit a variety of sex determining mechanisms including male or female heterogamety and haplodiploidy. The primary signal that starts sex determination is processed by a cascade of genes ending with the conserved switch doublesex that controls sexual differentiation. Transformer is the doublesex splicing regulator and has been found in all examined insects, indicating its ancestral function as a sex-determining gene. Despite this conserved function, the variation in transformer nucleotide sequence, amino acid composition and protein structure can accommodate a multitude of upstream sex determining signals. Transformer regulation of doublesex and its taxonomic distribution indicate that the doublesex-transformer axis is conserved among all insects and that transformer is the key gene around which variation in sex determining mechanisms has evolved.

  11. Study of Cu-Al-Zn alloys hardness temperature dependence

    International Nuclear Information System (INIS)

    Kurmanova, D.T.; Skakov, M.K.; Melikhov, V.D.

    2001-01-01

    In the paper the results of studies for the Cu-Al-Zn ternary alloys hardness temperature dependence are presented. The method of 'hot hardness' has been used during study of the solid state phase transformations and under determination of the hot stability boundaries. Due to the samples brittleness a hardness temperature dependence definition is possible only from 350-400 deg. C. Sensitivity of the 'hot hardness' method is decreasing within high plasticity range, so the measurements have been carried out only up to 700-800 deg. C. It is shown, that the alloys hardness dependence character from temperature is close to exponential one within the certain structure modification existence domain

  12. Using technology, choosing sex. The campaign against sex determination and the question of choice.

    Science.gov (United States)

    1992-01-01

    Women's groups and people's science and health groups formed the Forum Against Sex Determination and Sex Pre-Selection in November 1985 in Bombay, India, to prevent sex determination and sex preselection tests. The Forum considered sex determination and sex preselection to be an abuse of science and technology against people, especially women. Between 1901 and 1991, the sex ratio fell from 972 females/1000 males to 929/1000. The Forum saw the issue of sex determination and sex preselection as a link to oppression of and discrimination against females in all sectors of society. It also believed this to be a human rights issue. The Forum lobbied for a law regulating diagnostic techniques without banning them, since determining chromosomal abnormalities is important. The State of Maharashtra passed such a law in June 1988. It had some provisions which were counter-productive, however. For example, women undergoing a sex determination test must pay a fine of Rs 5 if found guilty of planning to terminate a pregnancy of a female fetus. Yet, neither the husband nor parents-in-law are liable, even though they often pressure women to undergo sex determination tests. The Forum's efforts and enactment of the law in Maharashtra have prompted other state governments and the central government to propose similar legislation. These state governments include Goa, Gujarat, and Orissa. The central government has met with organizations and individuals lobbying against misuse of diagnostic tests to obtain their counsel. The Forum does not feel comfortable with state control, however, since it tends to consider government to be against the people. Yet, the Forum did want the state to protect women's interests. It has raised important questions about technology, particularly concerning criteria to determine desirable and appropriate technologies.

  13. Temperature dependence of nitrogen solubility in iron base multicomponent melts

    International Nuclear Information System (INIS)

    Sokolov, V.M.; Koval'chuk, L.A.

    1986-01-01

    Method for calculating temperature dependence of nitrogen solubility in iron base multicomponent melts is suggested. Application areas of existing methods were determined and advantages of the new method for calculating nitrogen solubility in multicomponent-doped iron melts (Fe-Ni-Cr-Mo, Fe-Ni-Cr-Mn, Fe-Mo-V) at 1773-2073 K are shown

  14. Hysteresis and Temperature Dependency of Moisture Sorption – New Measurements

    DEFF Research Database (Denmark)

    Rode, Carsten; Hansen, Kurt Kielsgaard

    2011-01-01

    measurements of hysteresis and temperature dependency of the moisture sorption characteristics of three different porous building materials: aerated concrete, cement paste and spruce. Scanning curves are measured for all three materials where periods with adsorption and desorption interrupt each other...... intermittently. For one of the materials, aerated concrete, the sorption curves are determined at three different temperatures....

  15. Complementary sex determination in the parasitic wasp Diachasmimorpha longicaudata.

    Directory of Open Access Journals (Sweden)

    Leonela Carabajal Paladino

    Full Text Available We studied the sex determination in Diachasmimorpha longicaudata, a parasitoid braconid wasp widely used as biological control agent of fruit pest tephritid flies. We tested the complementary sex determination hypothesis (CSD known in at least 60 species of Hymenoptera. According to CSD, male or female development depends on the allelic composition of one sex locus (single-locus CSD or multiple sex loci (multiple-locus CSD. Hemizygote individuals are normal haploid males, and heterozygotes for at least one sex locus are normal diploid females, but homozygotes for all the sex loci are diploid males. In order to force the occurrence of diploid males in D. longicaudata, we established highly inbred lines and examined their offspring using chromosome counting, flow cytometry, and sex ratio analysis. We found that when mother-son crosses were studied, this wasp produced about 20% of diploid males out of the total male progeny. Our results suggest that this parasitoid may represent the second genus with multiple-locus CSD in Hymenoptera. Knowledge about the sex determination system in D. longicaudata is relevant for the improvement of mass rearing protocols of this species. This information also provides the necessary background for further investigations on the underlying molecular mechanisms of sex determination in this species, and a better insight into the evolution of this pathway in Hymenoptera in particular and insects in general.

  16. Vertebrate sex-determining genes play musical chairs.

    Science.gov (United States)

    Pan, Qiaowei; Anderson, Jennifer; Bertho, Sylvain; Herpin, Amaury; Wilson, Catherine; Postlethwait, John H; Schartl, Manfred; Guiguen, Yann

    2016-01-01

    Sexual reproduction is one of the most highly conserved processes in evolution. However, the genetic and cellular mechanisms making the decision of whether the undifferentiated gonad of animal embryos develops either towards male or female are manifold and quite diverse. In vertebrates, sex-determining mechanisms range from environmental to simple or complex genetic mechanisms and different mechanisms have evolved repeatedly and independently. In species with simple genetic sex-determination, master sex-determining genes lying on sex chromosomes drive the gonadal differentiation process by switching on a developmental program, which ultimately leads to testicular or ovarian differentiation. So far, very few sex-determining genes have been identified in vertebrates and apart from mammals and birds, these genes are apparently not conserved over a larger number of related orders, families, genera, or even species. To fill this knowledge gap and to better explore genetic sex-determination, we propose a strategy (RAD-Sex) that makes use of next-generation sequencing technology to identify genetic markers that define sex-specific segments of the male or female genome. Copyright © 2016 Académie des sciences. All rights reserved.

  17. Correlation between temperature dependence of elastic moduli and Debye temperature of paramagnetic metal

    International Nuclear Information System (INIS)

    Bodryakov, V.Yu.; Povzner, A.A.

    2000-01-01

    The correlation between the temperature dependence of elastic moduli and the Debye temperature of paramagnetic metal is analyzed in neglect of the temperature dependence of the Poison coefficient σ within the frames of the Debye-Grueneisen presentations. It is shown, that namely the temperature dependence of the elastic moduli determines primarily the temperature dependence of the Debye temperature Θ(T). On the other hand, the temperature dependence Θ(T) very weakly effects the temperature dependence of the elastic moduli. The later made it possible to formulate the self-consistent approach to calculation of the elastic moduli temperature dependence. The numerical estimates of this dependence parameters are conducted by the example of the all around compression modulus of the paramagnetic lutetium [ru

  18. Some progress in sexual reproduction and sex determination of ...

    African Journals Online (AJOL)

    As a result of this, elucidating the basic physiological mechanisms of algae becomes even more urgent. Of all the fields, sexual reproduction and sex determination are basic and essential aspects. In this review, we summarized the advances of sex in several typical algae which are of great economic importance and often ...

  19. Altering the sex determination pathway in Drosophila fat body modifies sex-specific stress responses.

    Science.gov (United States)

    Argue, Kathryn J; Neckameyer, Wendi S

    2014-07-01

    The stress response in Drosophila melanogaster reveals sex differences in behavior, similar to what has been observed in mammals. However, unlike mammals, the sex determination pathway in Drosophila is well established, making this an ideal system to identify factors involved in the modulation of sex-specific responses to stress. In this study, we show that the Drosophila fat body, which has been shown to be important for energy homeostasis and sex determination, is a dynamic tissue that is altered in response to stress in a sex and time-dependent manner. We manipulated the sex determination pathway in the fat body via targeted expression of transformer and transformer-2 and analyzed these animals for changes in their response to stress. In the majority of cases, manipulation of transformer or transformer-2 was able to change the physiological output in response to starvation and oxidative stress to that of the opposite sex. Our data also uncover the possibility of additional downstream targets for transformer and transformer-2 that are separate from the sex determination pathway and can influence behavioral and physiological responses. Copyright © 2014 the American Physiological Society.

  20. Cretaceous park of sex determination: sex chromosomes are conserved across iguanas.

    Science.gov (United States)

    Rovatsos, Michail; Pokorná, Martina; Altmanová, Marie; Kratochvíl, Lukáš

    2014-03-01

    Many poikilothermic vertebrate lineages, especially among amphibians and fishes, possess a rapid turnover of sex chromosomes, while in endotherms there is a notable stability of sex chromosomes. Reptiles in general exhibit variability in sex-determining systems; as typical poikilotherms, they might be expected to have a rapid turnover of sex chromosomes. However, molecular data which would enable the testing of the stability of sex chromosomes are lacking in most lineages. Here, we provide molecular evidence that sex chromosomes are highly conserved across iguanas, one of the most species-rich clade of reptiles. We demonstrate that members of the New World families Iguanidae, Tropiduridae, Leiocephalidae, Phrynosomatidae, Dactyloidae and Crotaphytidae, as well as of the family Opluridae which is restricted to Madagascar, all share homologous sex chromosomes. As our sampling represents the majority of the phylogenetic diversity of iguanas, the origin of iguana sex chromosomes can be traced back in history to the basal splitting of this group which occurred during the Cretaceous period. Iguanas thus show a stability of sex chromosomes comparable to mammals and birds and represent the group with the oldest sex chromosomes currently known among amniotic poikilothermic vertebrates.

  1. Investigation Of Temperature Dependent Characteristics Of ...

    African Journals Online (AJOL)

    The structure, magnetization and magnetostriction of Laves phase compound TbCo2 were investigated by temperature dependent high resolution neutron powder diffraction. The compound crystallizes in the cubic Laves phase C15 structure above its Curie temperature, TC and exhibits a rhombohedral distortion (space ...

  2. Temperature Dependent Models of Semiconductor Devices for ...

    African Journals Online (AJOL)

    The paper presents an investigation of the temperature dependent model of a diode and bipolar transistor built-in to the NAP-2 program and comparison of these models with experimentally measured characteristics of the BA 100 diode and BC 109 transistor. The detail of the modelling technique has been discussed and ...

  3. Temperature dependence of PZT film optical properties

    Czech Academy of Sciences Publication Activity Database

    Deineka, Alexander; Jastrabík, Lubomír; Suchaneck, G.; Gerlach, G.

    11-12, - (2001), s. 352-354 ISSN 0447-6441 R&D Projects: GA ČR GA202/00/1425; GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010914 Keywords : refractive index profile * PZT film * temperature dependence of optical properties Subject RIV: BH - Optics, Masers, Lasers

  4. Measurements of temperature dependence of 'localized susceptibility'

    CERN Document Server

    Shiozawa, H; Ishii, H; Takayama, Y; Obu, K; Muro, T; Saitoh, Y; Matsuda, T D; Sugawara, H; Sato, H

    2003-01-01

    The magnetic susceptibility of some rare-earth compounds is estimated by measuring magnetic circular dichroism (MCD) of rare-earth 3d-4f absorption spectra. The temperature dependence of the magnetic susceptibility obtained by the MCD measurement is remarkably different from the bulk susceptibility in most samples, which is attributed to the strong site selectivity of the core MCD measurement.

  5. How is sex determined in insects? An epilogue

    Indian Academy of Sciences (India)

    transcriptional factors, which bring about sexual dimorphism in adult flies. ... sex determination, in response to both internal and external selection forces. ... such as in the control of pests (e.g. C. capitata) and vectors of human diseases.

  6. Sex determination in Medfly: A molecular approach

    International Nuclear Information System (INIS)

    Saccone, G.; Pane, A.; Testa, G.; Santoro, M.; De Martino, G.; Di Paola, F.; Polito, L.C.; Louis, C.

    2000-01-01

    With the aim of developing new strategies of control to limit the damages inflicted on fruit crops by Ceratitis capitata (Wied.) (Medfly), a biotechnological approach is undertaken whereby female viability would be impaired or male viability would be improved following the introduction of specific genes into the genome of C. capitata. Only males will then be mass produced and released in the infested areas after sterilisation (Louis et al. 1987). Such conditional lethal or 'advantageous' genes could be expressed in transgenic flies either female-specifically or male-specifically by using cis regulative sequences obtained from previously isolated endogenous Ceratitis genes (Saccone et al. 1996, 1998). By using molecular strategies based on a subtractive technique, we have recently isolated male-specifically expressed genes in the Medfly. Furthermore, we present the current status of the research on the Ceratitis dsx gene, showing sex-specific alternative splicing as in Drosophila, and on the tra-inaZ strategy to induce in Drosophila flies female-specific conditional lethality

  7. Sex determination strategies in 2012: towards a common regulatory model?

    Science.gov (United States)

    2012-01-01

    Sex determination is a complicated process involving large-scale modifications in gene expression affecting virtually every tissue in the body. Although the evolutionary origin of sex remains controversial, there is little doubt that it has developed as a process of optimizing metabolic control, as well as developmental and reproductive functions within a given setting of limited resources and environmental pressure. Evidence from various model organisms supports the view that sex determination may occur as a result of direct environmental induction or genetic regulation. The first process has been well documented in reptiles and fish, while the second is the classic case for avian species and mammals. Both of the latter have developed a variety of sex-specific/sex-related genes, which ultimately form a complete chromosome pair (sex chromosomes/gonosomes). Interestingly, combinations of environmental and genetic mechanisms have been described among different classes of animals, thus rendering the possibility of a unidirectional continuous evolutionary process from the one type of mechanism to the other unlikely. On the other hand, common elements appear throughout the animal kingdom, with regard to a) conserved key genes and b) a central role of sex steroid control as a prerequisite for ultimately normal sex differentiation. Studies in invertebrates also indicate a role of epigenetic chromatin modification, particularly with regard to alternative splicing options. This review summarizes current evidence from research in this hot field and signifies the need for further study of both normal hormonal regulators of sexual phenotype and patterns of environmental disruption. PMID:22357269

  8. Sex determination mechanisms in the Calliphoridae (blow flies).

    Science.gov (United States)

    Scott, M J; Pimsler, M L; Tarone, A M

    2014-01-01

    The Calliphoridae or blow flies are a family of insects that occupy diverse habitats and perform important ecological roles, particularly the decomposition of animal remains. Some Calliphoridae species are also important in the forensic sciences, in agriculture (e.g. as livestock pests) and in medicine (e.g. maggot therapy). Calliphoridae provide striking examples in support of the hypothesis that sex determination regulatory gene hierarchies evolve in the reverse order, with the gene at the top being the most recently added. Unlike the model fly Drosophila melanogaster, where sex is determined by the number of X chromosomes, in the Australian sheep blow fly (Lucilia cuprina) sex is determined by a Y-linked male-determining gene (M). A different regulatory system appears to operate in the hairy maggot blow fly (Chrysomya rufifacies) where the maternal genotype determines sex. It is hypothesized that females heterozygous for a dominant female-determining factor (F/f) produce only female offspring and homozygous f/f females produce only sons. The bottom of the regulatory hierarchy appears to be the same in D. melanogaster and L. cuprina, with sex-specific splicing of doublesex transcripts being controlled by the female-specific Transformer (TRA) protein. We discuss a model that has been proposed for how tra transcripts are sex-specifically spliced in calliphorids, which is very different from D. melanogaster. © 2013 S. Karger AG, Basel.

  9. Sex determination using the Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) tool in a virtual environment.

    Science.gov (United States)

    Chapman, Tara; Lefevre, Philippe; Semal, Patrick; Moiseev, Fedor; Sholukha, Victor; Louryan, Stéphane; Rooze, Marcel; Van Sint Jan, Serge

    2014-01-01

    The hip bone is one of the most reliable indicators of sex in the human body due to the fact it is the most dimorphic bone. Probabilistic Sex Diagnosis (DSP: Diagnose Sexuelle Probabiliste) developed by Murail et al., in 2005, is a sex determination method based on a worldwide hip bone metrical database. Sex is determined by comparing specific measurements taken from each specimen using sliding callipers and computing the probability of specimens being female or male. In forensic science it is sometimes not possible to sex a body due to corpse decay or injury. Skeletalization and dissection of a body is a laborious process and desecrates the body. There were two aims to this study. The first aim was to examine the accuracy of the DSP method in comparison with a current visual sexing method on sex determination. A further aim was to see if it was possible to virtually utilise the DSP method on both the hip bone and the pelvic girdle in order to utilise this method for forensic sciences. For the first part of the study, forty-nine dry hip bones of unknown sex were obtained from the Body Donation Programme of the Université Libre de Bruxelles (ULB). A comparison was made between DSP analysis and visual sexing on dry bone by two researchers. CT scans of bones were then analysed to obtain three-dimensional (3D) virtual models and the method of DSP was analysed virtually by importing the models into a customised software programme called lhpFusionBox which was developed at ULB. The software enables DSP distances to be measured via virtually-palpated bony landmarks. There was found to be 100% agreement of sex between the manual and virtual DSP method. The second part of the study aimed to further validate the method by analysing thirty-nine supplementary pelvic girdles of known sex blind. There was found to be a 100% accuracy rate further demonstrating that the virtual DSP method is robust. Statistically significant differences were found in the identification of sex

  10. Temperature dependence of radiation chemistry of polymers

    International Nuclear Information System (INIS)

    Garrett, R.W.; Hill, D.J.T.; Le, T.T.; Milne, K.A.; O'Donnell, J.H.; Perera, S.M.C.; Pomery, P.J.

    1990-01-01

    Chemical reactions which occur during radiolysis of polymers usually show an increase in rate with increasing temperature that can be described by an Arrhenius relationship. The magnitude of the activation energy can vary widely and is affected by physical, as well as chemical, factors. Different reaction rates may be expected in crystalline and amorphous morphologies, and in glassy and rubbery regions. The temperature dependence of radiolysis reactions can be expected to show discontinuities at the glass and melting transitions, T g and T m . The ceiling temperature, T c , for polymerization/depolymerization will also affect the rate of degradation, especially for depropagation to monomer. The temperature for this effect depends on the molecular structure of the polymer. The temperature dependence of free radical reactions can be studied by cryogenic trapping and ESR spectroscopy during thermal profiling. Increased degradation rates at high dose rates can be due to increased temperatures resulting from energy absorption

  11. Temperature Dependence of Factors Controlling Isoprene Emissions

    Science.gov (United States)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  12. Sex determination mode does not affect body or genital development of the central bearded dragon (Pogona vitticeps

    Directory of Open Access Journals (Sweden)

    Sarah L. Whiteley

    2017-12-01

    Full Text Available Abstract Background The development of male- or female-specific phenotypes in squamates is typically controlled by either temperature-dependent sex determination (TSD or chromosome-based genetic sex determination (GSD. However, while sex determination is a major switch in individual phenotypic development, it is unknownhow evolutionary transitions between GSD and TSD might impact on the evolution of squamate phenotypes, particularly the fast-evolving and diverse genitalia. Here, we take the unique opportunity of studying the impact of both sex determination mechanisms on the embryological development of the central bearded dragon (Pogona vitticeps. This is possible because of the transitional sex determination system of this species, in which genetically male individuals reverse sex at high incubation temperatures. This can trigger the evolutionary transition of GSD to TSD in a single generation, making P. vitticeps an ideal model organism for comparing the effects of both sex determination processes in the same species. Results We conducted four incubation experiments on 265 P. vitticeps eggs, covering two temperature regimes (“normal” at 28 °C and “sex reversing” at 36 °C and the two maternal sexual genotypes (concordant ZW females or sex-reversed ZZ females. From this, we provide the first detailed staging system for the species, with a focus on genital and limb development. This was augmented by a new sex chromosome identification methodology for P. vitticeps that is non-destructive to the embryo. We found a strong correlation between embryo age and embryo stage. Aside from faster growth in 36 °C treatments, body and external genital development was entirely unperturbed by temperature, sex reversal or maternal sexual genotype. Unexpectedly, all females developed hemipenes (the genital phenotype of adult male P. vitticeps, which regress close to hatching. Conclusions The tight correlation between embryo age and embryo stage

  13. Rapid quantification and sex determination of forensic evidence materials.

    Science.gov (United States)

    Andréasson, Hanna; Allen, Marie

    2003-11-01

    DNA quantification of forensic evidence is very valuable for an optimal use of the available biological material. Moreover, sex determination is of great importance as additional information in criminal investigations as well as in identification of missing persons, no suspect cases, and ancient DNA studies. While routine forensic DNA analysis based on short tandem repeat markers includes a marker for sex determination, analysis of samples containing scarce amounts of DNA is often based on mitochondrial DNA, and sex determination is not performed. In order to allow quantification and simultaneous sex determination on minute amounts of DNA, an assay based on real-time PCR analysis of a marker within the human amelogenin gene has been developed. The sex determination is based on melting curve analysis, while an externally standardized kinetic analysis allows quantification of the nuclear DNA copy number in the sample. This real-time DNA quantification assay has proven to be highly sensitive, enabling quantification of single DNA copies. Although certain limitations were apparent, the system is a rapid, cost-effective, and flexible assay for analysis of forensic casework samples.

  14. Expression of putative sex-determining genes during the thermosensitive period of gonad development in the snapping turtle, Chelydra serpentina.

    Science.gov (United States)

    Rhen, T; Metzger, K; Schroeder, A; Woodward, R

    2007-01-01

    Modes of sex determination are quite variable in vertebrates. The developmental decision to form a testis or an ovary can be influenced by one gene, several genes, environmental variables, or a combination of these factors. Nevertheless, certain morphogenetic aspects of sex determination appear to be conserved in amniotes. Here we clone fragments of nine candidate sex-determining genes from the snapping turtle Chelydra serpentina, a species with temperature-dependent sex determination (TSD). We then analyze expression of these genes during the thermosensitive period of gonad development. In particular, we compare gene expression profiles in gonads from embryos incubated at a male-producing temperature to those from embryos at a female-producing temperature. Expression of Dmrt1 and Sox9 mRNA increased gradually at the male-producing temperature, but was suppressed at the female-producing temperature. This finding suggests that Dmrt1 and Sox9 play a role in testis development. In contrast, expression of aromatase, androgen receptor (Ar), and Foxl2 mRNA was constant at the male-producing temperature, but increased several-fold in embryos at the female-producing temperature. Aromatase, Ar, and Foxl2 may therefore play a role in ovary development. In addition, there was a small temperature effect on ER alpha expression with lower mRNA levels found in embryos at the female-producing temperature. Finally, Dax1, Fgf9, and SF-1 were not differentially expressed during the sex-determining period, suggesting these genes are not involved in sex determination in the snapping turtle. Comparison of gene expression profiles among amniotes indicates that Dmrt1 and Sox9 are part of a core testis-determining pathway and that Ar, aromatase, ER alpha, and Foxl2 are part of a core ovary-determining pathway. 2007 S. Karger AG, Basel

  15. Sex-specific determinants of fitness in a social mammal.

    Science.gov (United States)

    Lardy, Sophie; Allainé, Dominique; Bonenfant, Christophe; Cohas, Aurélie

    2015-11-01

    Sociality should evolve when the fitness benefits of group living outweigh the costs. Theoretical models predict an optimal group size maximizing individual fitness. However, beyond the number of individuals present in a group, the characteristics of these individuals, like their sex, are likely to affect the fitness payoffs of group living. Using 20 years of individually based data on a social mammal, the Alpine marmot (Marmota marmota), we tested for the occurrence of an optimal group size and composition, and for sex-specific effects of group characteristics on fitness. Based on lifetime data of 52 males and 39 females, our findings support the existence of an optimal group size maximizing male fitness and an optimal group composition maximizing fitness of males and females. Additionally, although group characteristics (i.e., size, composition and instability) affecting male and female fitness differed, fitness depended strongly on the number of same-sex subordinates within the social group in the two sexes. By comparing multiple measures of social group characteristics and of fitness in both sexes, we highlighted the sex-specific determinants of fitness in the two sexes and revealed the crucial role of intrasexual competition in shaping social group composition.

  16. Temperature dependent electronic conduction in semiconductors

    International Nuclear Information System (INIS)

    Roberts, G.G.; Munn, R.W.

    1980-01-01

    This review describes the temperature dependence of bulk-controlled electronic currents in semiconductors. The scope of the article is wide in that it contrasts conduction mechanisms in inorganic and organic solids and also single crystal and disordered semiconductors. In many experimental situations it is the metal-semiconductor contact or the interface between two dissimilar semiconductors that governs the temperature dependence of the conductivity. However, in order to keep the length of the review within reasonable bounds, these topics have been largely avoided and emphasis is therefore placed on bulk-limited currents. A central feature of electronic conduction in semiconductors is the concentrations of mobile electrons and holes that contribute to the conductivity. Various statistical approaches may be used to calculate these densities which are normally strongly temperature dependent. Section 1 emphasizes the relationship between the position of the Fermi level, the distribution of quantum states, the total number of electrons available and the absolute temperature of the system. The inclusion of experimental data for several materials is designed to assist the experimentalist in his interpretation of activation energy curves. Sections 2 and 3 refer to electronic conduction in disordered solids and molecular crystals, respectively. In these cases alternative approaches to the conventional band theory approach must be considered. For example, the velocities of the charge carriers are usually substantially lower than those in conventional inorganic single crystal semiconductors, thus introducing the possibility of an activated mobility. Some general electronic properties of these materials are given in the introduction to each of these sections and these help to set the conduction mechanisms in context. (orig.)

  17. Temperature dependence of giant dipole resonance width

    International Nuclear Information System (INIS)

    Vdovin, A.I.; Storozhenko, A.N.

    2005-01-01

    The quasiparticle-phonon nuclear model extended to finite temperature within the framework of the thermo field dynamics is applied to calculate a temperature dependence of the spreading width Γ d own of a giant dipole resonance. Numerical calculations are made for 12S n and 208 Pb nuclei. It is found that the width Γ d own increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones existing in the literature

  18. Temperature dependence of radiation effects in polyethylene

    International Nuclear Information System (INIS)

    Wu, G; Katsumura, Y.; Kudoh, H.; Morita, Y.; Seguchi, T.

    2000-01-01

    Temperature dependence of crosslinking and gas evolution under γ-irradiation was studied for high-density and low-density polyethylene samples in the 30-360degC range. It was found that crosslinking was the predominant process up to 300degC and the gel point decreased with increasing temperature. At above 300degC, however, the gel fraction at a given dose decreased rapidly with temperature and the action of radiation turned to enhance polyethylene degradation. Yields of H 2 and hydrocarbon gases increased with temperature and the compositions of hydrocarbons were dose dependent. (author)

  19. Efficacy of cheiloscopy in determination of sex among South indians.

    Science.gov (United States)

    Kautilya D, Vijay; Bodkha, Pravir; Rajamohan, Naveen

    2013-10-01

    Human identification plays a vital role in any crime investigation. Along with the various other established methods, cheiloscopy also plays a key role in linking the criminal with the crime. The ability of a technique in differentiating the sex of a person in the field can help in screening a large number of suspects. This study evaluated the efficacy of cheiloscopy in determination of sex among South Indians. It also studied the pattern of dimorphism in the lips and lip prints of south Indians. Lip prints from 100 medical students (50 males and 50 females) were obtained and were analyzed, based on Tsuchihashi and Suzuki classification, to check for dimorphism. Lip dimensions were studied by using standard sliding calipers for dimorphism. The most common pattern of lip print among males was Type III as compared to Type I in females. The outer four portions of the lip showed statistically significant differences in males and females. Middle portion of the lip was statistically insignificant in sex determination, based on lip print patterns. Thickness of the lip was significantly larger in males as compared to that in females and this criterion could be used to establish a logistic regression for determination of sex of a person. Lips not only significantly differ among the males and females in the pattern of the lip print that they present, but they also differ in their size. These features can effectively be used to determine the sex of a person accurately.

  20. Maternal provision of non-sex-specific transformer messenger RNA in sex determination of the wasp Asobara tabida.

    Science.gov (United States)

    Geuverink, E; Verhulst, E C; van Leussen, M; van de Zande, L; Beukeboom, L W

    2018-02-01

    In many insect species maternal provision of sex-specifically spliced messenger RNA (mRNA) of sex determination genes is an essential component of the sex determination mechanism. In haplodiploid Hymenoptera, maternal provision in combination with genomic imprinting has been shown for the parasitoid Nasonia vitripennis, known as maternal effect genomic imprinting sex determination (MEGISD). Here, we characterize the sex determination cascade of Asobara tabida, another hymenopteran parasitoid. We show the presence of the conserved sex determination genes doublesex (dsx), transformer (tra) and transformer-2 (tra2) orthologues in As. tabida. Of these, At-dsx and At-tra are sex-specifically spliced, indicating a conserved function in sex determination. At-tra and At-tra2 mRNA is maternally provided to embryos but, in contrast to most studied insects, As. tabida females transmit a non-sex-specific splice form of At-tra mRNA to the eggs. In this respect, As. tabida sex determination differs from the MEGISD mechanism. How the paternal genome can induce female development in the absence of maternal provision of sex-specifically spliced mRNA remains an open question. Our study reports a hitherto unknown variant of maternal effect sex determination and accentuates the diversity of insect sex determination mechanisms. © 2017 The Authors. Insect Molecular Biology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.

  1. Temperature dependence of coherence in transmon qubits

    Energy Technology Data Exchange (ETDEWEB)

    Schloer, Steffen; Braumueller, Jochen; Lukashenko, Oleksandr; Rotzinger, Hannes; Weides, Martin; Ustinov, Alexey V. [Physikalisches Institut, KIT, Karlsruhe (Germany); Sandberg, Martin; Vissers, Michael R.; Pappas, David P. [NIST, Boulder, CO (United States)

    2015-07-01

    Superconducting qubits are a promising field of research, not only with respect to quantum computing but also as highly sensitive detectors and due to the possibility of using them to study fundamental implications of quantum mechanics. The requirements for qubits that can be used as building blocks in a potential quantum computer are challenging. Modern superconducting qubits like the transmon are strong candidates for achieving these goals. The main challenge here is to increase the coherence of prepared quantum states. Here, we experimentally investigate the influence of temperature variation on relaxation and dephasing of a transmon qubit. Our goal is to understand decoherence mechanisms in material optimized circuits. Aiming at longer coherence, in this case peaking over 50 μs for T{sub 1} and T{sub 2}, our samples are fabricated at NIST using two different materials. Low-loss TiN was used for the shunt capacitance as well as the resonator, combined with shadow evaporated ultra-small Al-AlO{sub x}-Al Josephson junctions. We will present temperature-dependent data on qubit relaxation and dephasing times as well as power spectra. Our data will be compared to previously obtained temperature dependent data for other types of qubits.

  2. (Alpha-) quenching temperature dependence in liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Arnd; Lozza, Valentina; Krosigk, Belina von; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, TU Dresden (Germany)

    2015-07-01

    Liquid scintillator (LS) is an effective and promising detector material, which is and will be used by many small and large scale experiments. In order to perform correct signal identification and background suppression, a very good knowledge of LS properties is crucial. One of those is the light yield from alpha particles in liquid scintillator. This light output strongly quenched, approx. 10 times compared to that of electrons, and has been precisely studied at room temperature for various LS. Big scintillator experiments, such as SNO+ and maybe future large scale detectors, will operate at different temperatures. While a strong temperature dependence is well known for solid state scintillators, due to the different scintillation process, a quenching temperature dependence in LS is usually assumed negligible. On the other hand, inconsistencies in between measurements are often explained by potential temperature effects. This study investigates LAB based liquid scintillator with an intrinsic, dissolved alpha emitter and its behaviour with temperature change. In a small, cooled and heated setup, a stabilized read-out with two PMTs is realised. First results are presented.

  3. Modeling the temperature dependence of thermophysical properties: Study on the effect of temperature dependence for RFA.

    Science.gov (United States)

    Watanabe, Hiroki; Kobayashi, Yo; Hashizume, Makoto; Fujie, Masakatsu G

    2009-01-01

    Radio frequency ablation (RFA) has increasingly been used over the past few years and RFA treatment is minimally invasive for patients. However, it is difficult for operators to control the precise formation of coagulation zones due to inadequate imaging modalities. With this in mind, an ablation system using numerical simulation to analyze the temperature distribution of the organ is needed to overcome this deficiency. The objective of our work is to develop a temperature dependent thermophysical liver model. First, an overview is given of the development of the thermophysical liver model. Second, a simulation to evaluate the effect of temperature dependence of the thermophysical properties of the liver is explained. Finally, the result of the simulation, which indicated that the temperature dependence of thermophysical properties accounts for temperature differences influencing the accuracy of RFA treatment is described.

  4. Sex determination in the Lesser Flamingo ( Phoenicopterus minor ...

    African Journals Online (AJOL)

    PCR amplification of the CHD-Z and CHD-W genes using DNA extracted from the blood samples was used to determine the sex of each bird. There were significant differences in mass and tarsus length among the three age groups, indicating that Lesser Flamingos continue to grow in skeletal size and mass between ...

  5. Correction of SiPM temperature dependencies

    International Nuclear Information System (INIS)

    Kaplan, A.

    2009-01-01

    The performance of a high granular analogue hadronic calorimeter (AHCAL) using scintillator tiles with built-in Silicon Photomultiplier (SiPM) readout is reported. A muon beam is used for the minimum ionizing particle (MIP) based calibration of the single cells. The calibration chain including corrections for the non-linearity of the SiPM is presented. The voltage and temperature dependencies of the SiPM signal have been investigated using the versatile LED system of the AHCAL. Monitoring and correction methods are discussed. Measurements from the operation 2006 and 2007 at the CERN SPS test beam and data provided by the Institute for Theoretical and Experimental Physics (ITEP) in Moscow are compared.

  6. Temperature dependency in motor skill learning.

    Science.gov (United States)

    Immink, Maarten A; Wright, David L; Barnes, William S

    2012-01-01

    The present study investigated the role of temperature as a contextual condition for motor skill learning. Precision grip task training occurred while forearm cutaneous temperature was either heated (40-45 °C) or cooled (10-15 °C). At test, temperature was either reinstated or changed. Performance was comparable between training conditions while at test, temperature changes decreased accuracy, especially after hot training conditions. After cold training, temperature change deficits were only evident when concurrent force feedback was presented. These findings are the first evidence of localized temperature dependency in motor skill learning in humans. Results are not entirely accounted for by a context-dependent memory explanation and appear to represent an interaction of neuromuscular and sensory processes with the temperature present during training and test.

  7. Temperature dependent quasiparticle renormalization in nickel metal

    Energy Technology Data Exchange (ETDEWEB)

    Ovsyannikov, Ruslan; Sanchez-Barriga, Jaime; Fink, Joerg; Duerr, Hermann A. [Helmholtz Zentrum Berlin (Germany). BESSY II

    2009-07-01

    One of the fundamental consequences of electron correlation effects is that the bare particles in solids become 'dressed', i.e. they acquire an increased effective mass and a lifetime. We studied the spin dependent quasiparticle band structure of Ni(111) with high resolution angle resolved photoemission spectroscopy. At low temperatures (50 K) a renormalization of quasiparticle energy and lifetime indicative of electron-phonon coupling is observed in agreement with literature. With increasing temperature we observe a decreasing quasiparticle lifetime at the Fermi level for all probed minority spin bands as expected from electron phonon coupling. Surprisingly the majority spin states behave differently. We actually observe a slightly increased lifetime at room temperature. The corresponding increase in Fermi velocity points to a temperature dependent reduction of the majority spin quasiparticle renormalization.

  8. Temperature Dependent Wire Delay Estimation in Floorplanning

    DEFF Research Database (Denmark)

    Winther, Andreas Thor; Liu, Wei; Nannarelli, Alberto

    2011-01-01

    Due to large variations in temperature in VLSI circuits and the linear relationship between metal resistance and temperature, the delay through wires of the same length can be different. Traditional thermal aware floorplanning algorithms use wirelength to estimate delay and routability. In this w......Due to large variations in temperature in VLSI circuits and the linear relationship between metal resistance and temperature, the delay through wires of the same length can be different. Traditional thermal aware floorplanning algorithms use wirelength to estimate delay and routability....... In this work, we show that using wirelength as the evaluation metric does not always produce a floorplan with the shortest delay. We propose a temperature dependent wire delay estimation method for thermal aware floorplanning algorithms, which takes into account the thermal effect on wire delay. The experiment...

  9. Sex and PRNP genotype determination in preimplantation caprine embryos.

    Science.gov (United States)

    Guignot, F; Perreau, C; Cavarroc, C; Touzé, J-L; Pougnard, J-L; Dupont, F; Beckers, J-F; Rémy, B; Babilliot, J-M; Bed'Hom, B; Lamorinière, J M; Mermillod, P; Baril, G

    2011-08-01

    The objective of this study was to test the accuracy of genotype diagnosis after whole amplification of DNA extracted from biopsies obtained by trimming goat embryos and to evaluate the viability of biopsied embryos after vitrification/warming and transfer. Whole genome amplification (WGA) was performed using Multiple Displacement Amplification (MDA). Sex and prion protein (PRNP) genotypes were determined. Sex diagnosis was carried out by PCR amplification of ZFX/ZFY and Y chromosome-specific sequences. Prion protein genotype determination was performed on codons 142, 154, 211, 222 and 240. Embryos were collected at day 7 after oestrus and biopsied either immediately after collection (blastocysts and expanded blastocysts) or after 24 h of in vitro culture (compacted morulae). Biopsied embryos were frozen by vitrification. Vitrified whole embryos were kept as control. DNA of biopsies was extracted and amplified using MDA. Sex diagnosis was efficient for 97.4% of biopsies and PRNP genotyping was determined in 78.7% of biopsies. After embryo transfer, no significant difference was observed in kidding rate between biopsied and vitrified control embryos, whereas embryo survival rate was different between biopsied and whole vitrified embryos (p = 0.032). At birth, 100% of diagnosed sex and 98.2% of predetermined codons were correct. Offspring PRNP profiles were in agreement with parental genotype. Whole genome amplification with MDA kit coupled with sex diagnosis and PRNP genotype predetermination are very accurate techniques to genotype goat embryos before transfer. These novel results allow us to plan selection of scrapie-resistant genotypes and kid sex before transfer of cryopreserved embryo. © 2010 Blackwell Verlag GmbH.

  10. Interactions of Socioeconomic Determinants, Offspring Sex Preference and Fertility Behavior

    Directory of Open Access Journals (Sweden)

    Paul M. Sharp

    2011-01-01

    Full Text Available Using path anaysis and the 5% PUMS data of the 1990 and 2000 censuses, this study examines 1 the correlation between Chinese-American sex preference for children and their fertility behavior, and 2 the interaction between the sex preference and its socioeconomic determinants. Of normative and non-normative factors investegated in this study, offspring sex preference is the greatest stimulus to Chinese fertility. Of socioeconomic variables, women’s educational attainment plays a primary role in depressing the impact of son preference in addition to their increasing stay in the host society. However, these two factors do not work on their husbands in the same way, demonstrating men’s inflexible attitudes toward gender roles in the family and in society. Son preference exerts positive impact on American-Chinese fertility and prevent from further decline. Yet, the influence has been diminishing since 1990 as observed in this study.

  11. Pulp tissue in sex determination: A fluorescent microscopic study

    Science.gov (United States)

    Nayar, Amit; Singh, Harkanwal Preet; Leekha, Swati

    2014-01-01

    Aims: To determine and compare the reliability of pulp tissue in determination of sex and to analyze whether caries have any effect on fluorescent body test. Materials and Methods: This study was carried on 50 maxillary and mandibular teeth (25 male teeth and 25 female teeth), which were indicated for extraction. The teeth are categorized into 5 groups, 10 each (5 from males and 5 from females) on the basis of caries progression. The pulp cells are stained with quinacrine hydrochloride and observed with fluorescent microscope for fluorescent body. Gender is determined by identification of Y chromosome fluorescence in dental pulp. Results: Fluorescent bodies were found to be more in sound teeth in males as the caries increase the mean percentage of fluorescent bodies observed decreases in males. We also observed the fluorescent spots in females, and the value of the spot increases in female as the caries progresses, thereby giving false positive results in females. Conclusion: Sex determination by fluorescent staining of the Y chromosome is a reliable technique in teeth with healthy pulps or caries with enamel or up to half way of dentin. Teeth with caries involving pulp cannot be used for sex determination. PMID:25125912

  12. Liquid-filled ionization chamber temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Franco, L. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain)]. E-mail: luciaff@usc.es; Gomez, F. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain); Iglesias, A. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain); Pardo, J. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain); Pazos, A. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain); Pena, J. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain); Zapata, M. [Dpto. de Fisica de Particulas, Facultade de Fisica, Universidade de Santiago, Campus Sur S/N, 15782 Santiago de Compostela (Spain)

    2006-05-10

    Temperature and pressure corrections of the read-out signal of ionization chambers have a crucial importance in order to perform high-precision absolute dose measurements. In the present work the temperature and pressure dependences of a sealed liquid isooctane filled ionization chamber (previously developed by the authors) for radiotherapy applications have been studied. We have analyzed the thermal response of the liquid ionization chamber in a {approx}20 deg. C interval around room temperature. The temperature dependence of the signal can be considered linear, with a slope that depends on the chamber collection electric field. For example, a relative signal slope of 0.27x10{sup -2}K{sup -1} for an operation electric field of 1.67x10{sup 6}Vm{sup -1} has been measured in our detector. On the other hand, ambient pressure dependence has been found negligible, as expected for liquid-filled chambers. The thermal dependence of the liquid ionization chamber signal can be parametrized within the Onsager theory on initial recombination. Considering that changes with temperature of the detector response are due to variations in the free ion yield, a parametrization of this dependence has been obtained. There is a good agreement between the experimental data and the theoretical model from the Onsager framework.

  13. Temperature-dependent ion beam mixing

    International Nuclear Information System (INIS)

    Rehn, L.E.; Alexander, D.E.

    1993-08-01

    Recent work on enhanced interdiffusion rates during ion-beam mixing at elevated temperatures is reviewed. As discussed previously, expected increase in ion-beam mixing rates due to 'radiation-enhanced diffusion' (RED), i.e. the free migration of isolated vacancy and interstitial defects, is well documented in single-crystal specimens in the range of 0.4 to 0.6 of absolute melting temperature. In contrast, the increase often observed at somewhat lower temperatures during ion-beam mixing of polycrystalline specimens is not well understood. However, sufficient evidence is available to show that this increase reflects intracascade enhancement of a thermally-activated process that also occurs without irradiation. Recent evidence is presented which suggests that this process is Diffusion-induced Grain-Boundary Migration (DIGM). An important complementary conclusion is that because ion-beam mixing in single-crystal specimens exhibits no significant temperature dependence below that of RED, models that invoke only irradiation-specific phenomena, e.g., cascade-overlap, thermal-spikes, or liquid-diffusion, and hence which predict no difference in mixing behavior between single- or poly-crystalline specimens, cannot account for the existing results

  14. Temperature dependence in magnetic particle imaging

    Science.gov (United States)

    Wells, James; Paysen, Hendrik; Kosch, Olaf; Trahms, Lutz; Wiekhorst, Frank

    2018-05-01

    Experimental results are presented demonstrating how temperature can influence the dynamics of magnetic nanoparticles (MNPs) in liquid suspension, when exposed to alternating magnetic fields in the kilohertz frequency range. The measurements used to probe the nanoparticle systems are directly linked to both the emerging biomedical technique of magnetic particle imaging (MPI), and to the recently proposed concept of remote nanoscale thermometry using MNPs under AC field excitation. Here, we report measurements on three common types of MNPs, two of which are currently leading candidates for use as tracers in MPI. Using highly-sensitive magnetic particle spectroscopy (MPS), we demonstrate significant and divergent thermal dependences in several key measures used in the evaluation of MNP dynamics for use in MPI and other applications. The temperature range studied was between 296 and 318 Kelvin, making our findings of particular importance for MPI and other biomedical technologies. Furthermore, we report the detection of the same temperature dependences in measurements conducted using the detection coils within an operational preclinical MPI scanner. This clearly shows the importance of considering temperature during MPI development, and the potential for temperature-resolved MPI using this system. We propose possible physical explanations for the differences in the behaviors observed between the different particle types, and discuss our results in terms of the opportunities and concerns they raise for MPI and other MNP based technologies.

  15. Genetic architecture of sex determination in fish: Applications to sex ratio control in aquaculture

    Directory of Open Access Journals (Sweden)

    Paulino eMartínez

    2014-09-01

    Full Text Available Controlling the sex ratio is essential in finfish farming. A balanced sex ratio is usually good for broodstock management, since it enables to develop appropriate breeding schemes. However, in some species the production of monosex populations is desirable because the existence of sexual dimorphism, primarily in growth or first time of sexual maturation, but also in color or shape, can render one sex more valuable. The knowledge of the genetic architecture of sex determination (SD is convenient for controlling sex ratio and for the implementation of breeding programs. Unlike mammals and birds, which show highly conserved master genes that control a conserved genetic network responsible for gonad differentiation (GD, a huge diversity of SD mechanisms has been reported in fish. Despite theory predictions, more than one gene is in many cases involved in fish SD and genetic differences have been observed in the GD network. Environmental factors also play a relevant role and epigenetic mechanisms are becoming increasingly recognized for the establishment and maintenance of the GD pathways. Although major genetic factors are frequently involved in fish SD, these observations strongly suggest that SD in this group resembles a complex trait. Accordingly, the application of quantitative genetics combined with genomic tools is desirable to address its study and in fact, when applied, it has frequently demonstrated a multigene trait interacting with environmental factors in model and cultured fish species. This scenario has notable implications for aquaculture and, depending upon the species, from chromosome manipulation or environmental control techniques up to classical selection or marker assisted selection programs, are being applied. In this review, we selected four relevant species or fish groups to illustrate this diversity and hence the technologies that can be used by the industry for the control of sex ratio: turbot and European sea bass, two

  16. Single locus complementary sex determination in Hymenoptera: an "unintelligent" design?

    Directory of Open Access Journals (Sweden)

    Driessen Gerard

    2006-01-01

    Full Text Available Abstract The haplodiploid sex determining mechanism in Hymenoptera (males are haploid, females are diploid has played an important role in the evolution of this insect order. In Hymenoptera sex is usually determined by a single locus, heterozygotes are female and hemizygotes are male. Under inbreeding, homozygous diploid and sterile males occur which form a genetic burden for a population. We review life history and genetical traits that may overcome the disadvantages of single locus complementary sex determination (sl-CSD. Behavioural adaptations to avoid matings between relatives include active dispersal from natal patches and mating preferences for non-relatives. In non-social species, temporal and spatial segregation of male and female offspring reduces the burden of sl-CSD. In social species, diploid males are produced at the expense of workers and female reproductives. In some social species, diploid males and diploid male producing queens are killed by workers. Diploid male production may have played a role in the evolution or maintenance of polygyny (multiple queens and polyandry (multiple mating. Some forms of thelytoky (parthenogenetic female production increase homozygosity and are therefore incompatible with sl-CSD. We discuss a number of hypothetical adaptations to sl-CSD which should be considered in future studies of this insect order.

  17. Temperature dependence of gafchromic MD-55 dosimeter

    International Nuclear Information System (INIS)

    Klassen, Norman V.; Zwan, Len van der; Cygler, Joanna

    1997-01-01

    Objective: Gafchromic MD-55 is a fairly new, thin film dosimeter that develops a blue color (λ max = 676 nm) when irradiated with ionizing radiation. The increase in absorbance is nearly proportional to the absorbed dose. MD-55 can be used for high precision dosimetry if care is taken to assure reproducible film orientation in the spectrophotometer as well as temperature control during both irradiation and reading. In order to achieve the maximum sensitivity of this dosimeter the readings of the optical density should be taken at λ max . It was reported for another type of Gafchromic film (DM-1260), that both λ max and ε max decrease with an increase in the temperature of the spectrophotometer. The purpose of this study was to characterize the reading temperature dependence of the new type of Gafchromic film available on the market and to find optimal conditions for using it for high precision dosimetry. Materials and Methods: Irradiations were carried out using 60 Co gamma rays from an Eldorado irradiator. The dosimeters were sandwiched in a lucite phantom with 4.4 mm build-up and irradiated in the center of a 10 cm x 10 cm field at 1 meter from the source. The temperature during irradiations was 22 deg. C. The dose rate was about 0.68 Gy/min. Measurements of optical density were made using a Cary 210 spectrophotometer. A bandpass of 3.5 nm was used. The temperature of the baseplate of the sample holder was regulated to +/-0.05 deg. C and measured by a probe lying on the baseplate. In all cases, values of OD were only recorded after they had come to a constant value, which was reached within 5 minutes of inserting the dosimeter into the sample chamber of the spectrophotometer. Results: The temperature dependence of the OD at 676 nm was measured in 2 studies using 6 dosimeters that had received 0, 1.0, 3.5, 6.2, 14.5 Gy. Readings were taken at 7 temperatures between 18.8 and 28.1 deg. C. By returning to the initial temperature several hours later, it was found

  18. Sex Determination in Insects: a binary decision based on alternative splicing

    OpenAIRE

    Salz, Helen K.

    2011-01-01

    The gene regulatory networks that control sex determination vary between species. Despite these differences, comparative studies in insects have found that alternative splicing is reiteratively used in evolution to control expression of the key sex determining genes. Sex determination is best understood in Drosophila where activation of the RNA binding protein encoding gene Sex-lethal is the central female-determining event. Sex-lethal serves as a genetic switch because once activated it cont...

  19. On the Temperature Dependence of Enzyme-Catalyzed Rates.

    Science.gov (United States)

    Arcus, Vickery L; Prentice, Erica J; Hobbs, Joanne K; Mulholland, Adrian J; Van der Kamp, Marc W; Pudney, Christopher R; Parker, Emily J; Schipper, Louis A

    2016-03-29

    One of the critical variables that determine the rate of any reaction is temperature. For biological systems, the effects of temperature are convoluted with myriad (and often opposing) contributions from enzyme catalysis, protein stability, and temperature-dependent regulation, for example. We have coined the phrase "macromolecular rate theory (MMRT)" to describe the temperature dependence of enzyme-catalyzed rates independent of stability or regulatory processes. Central to MMRT is the observation that enzyme-catalyzed reactions occur with significant values of ΔCp(‡) that are in general negative. That is, the heat capacity (Cp) for the enzyme-substrate complex is generally larger than the Cp for the enzyme-transition state complex. Consistent with a classical description of enzyme catalysis, a negative value for ΔCp(‡) is the result of the enzyme binding relatively weakly to the substrate and very tightly to the transition state. This observation of negative ΔCp(‡) has important implications for the temperature dependence of enzyme-catalyzed rates. Here, we lay out the fundamentals of MMRT. We present a number of hypotheses that arise directly from MMRT including a theoretical justification for the large size of enzymes and the basis for their optimum temperatures. We rationalize the behavior of psychrophilic enzymes and describe a "psychrophilic trap" which places limits on the evolution of enzymes in low temperature environments. One of the defining characteristics of biology is catalysis of chemical reactions by enzymes, and enzymes drive much of metabolism. Therefore, we also expect to see characteristics of MMRT at the level of cells, whole organisms, and even ecosystems.

  20. Gender/Sex as a Social Determinant of Cardiovascular Risk.

    Science.gov (United States)

    O'Neil, Adrienne; Scovelle, Anna J; Milner, Allison J; Kavanagh, Anne

    2018-02-20

    The social gradient for cardiovascular disease (CVD) onset and outcomes is well established. The American Heart Association's Social Determinants of Risk and Outcomes of Cardiovascular Disease Scientific Statement advocates looking beyond breakthroughs in biological science toward a social determinants approach that focuses on socioeconomic position, race and ethnicity, social support, culture and access to medical care, and residential environments to curb the burden of CVD going forward. Indeed, the benefits of this approach are likely to be far reaching, enhancing the positive effects of advances in CVD related to prevention and treatment while reducing health inequities that contribute to CVD onset and outcomes. It is disappointing that the role of gender has been largely neglected despite being a critical determinant of cardiovascular health. It is clear that trajectories and outcomes of CVD differ by biological sex, yet the tendency for sex and gender to be conflated has contributed to the idea that both are constant or fixed with little room for intervention. Rather, as distinct from biological sex, gender is socially produced. Overlaid on biological sex, gender is a broad term that shapes and interacts with one's cognition to guide norms, roles, behaviors, and social relations. It is a fluid construct that varies across time, place, and life stage. Gender can interact with biological sex and, indeed, other social determinants, such as ethnicity and socioeconomic position, to shape cardiovascular health from conception, through early life when health behaviors and risk factors are shaped, into adolescence and adulthood. This article will illustrate how gender shapes the early adoption of health behaviors in childhood, adolescence, and young adulthood by focusing on physical activity, drinking, and smoking behaviors (including the influence of role modeling). We will also discuss the role of gender in psychosocial stress with a focus on trauma from life

  1. Canine index – A tool for sex determination

    Directory of Open Access Journals (Sweden)

    Shankar M. Bakkannavar

    2015-12-01

    Full Text Available Teeth are most useful tools in victim identification in the living as well as the dead in the field of forensic investigations. Their ability to survive in situations like mass disasters makes them constructive devices. Many authors have measured crowns of teeth in both males and females and found certain variations. Canines, reported to survive in air crash and hurricane disasters, are perhaps the most stable teeth in the oral cavity because of the labiolingual thickness of the crown and the root anchorage in the alveolar process of jaws. Measurement of mesiodistal width of the mandibular canines and inter-canine distance of the mandible provides good evidence of sex identification due to dimorphism. This study was undertaken to evaluate the effectiveness of canine index (CI in the determination of sex.

  2. MORPHOMETRIC EVALUATION OF FORAMEN MAGNUM FOR SEX DETERMINATION IN A DOCUMENTED NORTH INDIAN SAMPLE

    OpenAIRE

    Jain; Alok Kumar; Pankaj

    2013-01-01

    ABSTRACT: Sex determination is used in anthropology, forensic medicine and medic o - legal cases. It is (1) remarked that “next to the pelvis, the skull is the most easily sexed portion of the skeleton”. It has been suggested (2 - 5) that the measurements of the foramen magnum are useful for determining the sex. There are two osteological techniques used to determine the sex of an individual; the first is visual assessment to evaluate the morphological sex tra...

  3. Temperature dependence of autoxidation of perilla oil and tocopherol degradation.

    Science.gov (United States)

    Wang, Seonyeong; Hwang, Hyunsuk; Yoon, Sukhoo; Choe, Eunok

    2010-08-01

    Temperature dependence of the autoxidation of perilla oil and tocopherol degradation was studied with corn oil as a reference. The oils were oxidized in the dark at 20, 40, 60, and 80 degrees C. Oil oxidation was determined by peroxide and conjugated dienoic acid values. Tocopherols in the oils were quantified by HPLC. The oxidation of both oils increased with oxidation time and temperature. Induction periods for oil autoxidation decreased with temperature, and were longer in corn oil than in perilla oil, indicating higher sensitivity of perilla oil to oxidation. However, time lag for tocopherol degradation was longer in perilla oil, indicating higher stability of tocopherols in perilla oil than in corn oil. Activation energies for oil autoxidation and tocopherol degradation were higher in perilla oil (23.9 to 24.2, 9.8 kcal/mol, respectively) than in corn oil (12.5 to 15.8, 8.8 kcal/mol, respectively) indicating higher temperature-dependence in perilla oil. Higher stability of tocopherols in perilla oil was highly related with polyphenols. The study suggests that more careful temperature control is required to decrease the autoxidation of perilla oil than that of corn oil, and polyphenols contributed to the oxidative stability of perilla oil by protecting tocopherols from degradation, especially at the early stage of oil autoxidation.

  4. Temperature-dependent photoluminescence from CdS/Si nanoheterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yue Li; Li, Yong; Ji, Peng Fei; Zhou, Feng Qun; Sun, Xiao Jun; Yuan, Shu Qing; Wan, Ming Li [Pingdingshan University, Department of Physics, Solar New Energy Research Center, Pingdingshan (China); Ling, Hong [North China University of Water Resources and Electric Power, Department of Mathematics and Information Science, Zhengzhou (China)

    2016-12-15

    CdS/Si nanoheterojunctions have been fabricated by growing nanocrystal CdS (nc-CdS) on the silicon nanoporous pillar array (Si-NPA) through using a chemical bath deposition method. The nanoheterojunctions have been constructed by three layers: the upper layer being a nc-CdS thin films, the intermediate layer being the interface region including nc-CdS and nanocrystal silicon (nc-Si), and the bottom layer being nc-Si layer grown on sc-Si substrate. The room temperature and temperature-dependent photoluminescence (PL) have been measured and analyzed to provide some useful information of defect states. Utilizing the Gauss-Newton fitting method, five emission peaks from the temperature-dependent PL spectra can be determined. From the high energy to low energy, these five peaks are ascribed to the some luminescence centers which are formed by the oxygen-related deficiency centers in the silicon oxide layer of Si-NPA, the band gap emission of nc-CdS, the transition from the interstitial cadmium (I{sub Cd}) to the valence band, the recombination from I{sub Cd} to cadmium vacancies (V{sub Cd}), and from sulfur vacancies (V{sub s}) to the valence band, respectively. Understanding of the defect states in the CdS/Si nanoheterojunctions is very meaningful for the performance of devices based on CdS/Si nanoheterojunctions. (orig.)

  5. On the temperature dependence of the excess resistivity in dilute volatile alloys

    International Nuclear Information System (INIS)

    Uray, L.; Vicsek, T.

    1978-01-01

    In recrystallized wires of many important refractory alloys, an appreciable part of the temperature dependence of the measured excess resistivity is related to the radial distribution of the volatile solutes (extrinsic temperature dependence). Both the extrinsic and the intrinsic part of the temperature dependence of the excess resistivity have been determined for dilute WFe, WCo and WRe alloys, by measuring the resistance as a function of temperature and the thickness of layers removed by electrothinning. In this way the parameters of the evaporation profiles were also determined. In the surface region at low temperatures the length scale of the inhomogeneity is comparable to the mean-free path. Therefore, the observed extrinsic temperature dependence of the excess resistivity was calculated directly from the Boltzmann equation. The WCo alloy is a Kondo system, since its resistivity shows a minimum a 20 K. (author)

  6. When daughters are unwanted. Sex determination tests in India.

    Science.gov (United States)

    Kishwar, M

    1995-01-01

    Amniocentesis and ultrasound have been used for detecting fetal abnormalities, but in India they have been used for sex determination, leading to the abortion of hundreds of thousands of female fetuses. As a result, by 1991 the sex ratio had declined to 929 females per 1000 males from 972 females per 1000 males in 1901. This amounts to a deficit of almost 30 million females in the whole population. The regional prevalence of sex preferences has spread horizontally and vertically in the south and the northeast, where the ratios used to be more favorable. A ban on such prenatal diagnosis was passed in several states, but it proved to be ineffective and unenforceable. The result was only that the fees charged soared. Finally, in August 1994 the Indian Parliament enacted the Prenatal Diagnostics Techniques Act that prohibited genetic counseling centers to perform such procedures unless strict criteria were observed (age over 35 years, two or more previous abortions, exposure to drugs, infections, and mental or physical retardation). However, the emergence of a police-doctor nexus is dangerous for the well-being of any society and could lead to criminalization of the medical profession. Some doctors also rationalize this practice as a means of controlling population, because the custom continues to have children until the desired number of sons are born. In low sex ratio regions seclusion, disinheritance of women from property, low female literacy, poor health, greater incidence of domestic violence, and low employment rates are typical. The aversion to female infants is a culturally conditioned choice which materializes in the pervasive dread of daughters. Women themselves perpetuate the dread because of their own misery, low status, abuse, and the burden of the dowry. The devaluation of women is rooted in history, particularly in the northwest where constant wars favored a martial society for males (with strict purdah for females), and in addition British colonialism

  7. Temperature dependence of bulk viscosity in water using acoustic spectroscopy

    International Nuclear Information System (INIS)

    Holmes, M J; Parker, N G; Povey, M J W

    2011-01-01

    Despite its fundamental role in the dynamics of compressible fluids, bulk viscosity has received little experimental attention and there remains a paucity of measured data. Acoustic spectroscopy provides a robust and accurate approach to measuring this parameter. Working from the Navier-Stokes model of a compressible fluid one can show that the bulk viscosity makes a significant and measurable contribution to the frequency-squared acoustic attenuation. Here we employ this methodology to determine the bulk viscosity of Millipore water over a temperature range of 7 to 50 0 C. The measured attenuation spectra are consistent with the theoretical predictions, while the bulk viscosity of water is found to be approximately three times larger than its shear counterpart, reinforcing its significance in acoustic propagation. Moreover, our results demonstrate that this technique can be readily and generally applied to fluids to accurately determine their temperature dependent bulk viscosities.

  8. [Molecular mechanisms in sex determination: from gene regulation to pathology].

    Science.gov (United States)

    Ravel, C; Chantot-Bastaraud, S; Siffroi, J-P

    2004-01-01

    Testis determination is the complex process by which the bipotential gonad becomes a normal testis during embryo development. As a consequence, this process leads to sexual differentiation corresponding to the masculinization of both genital track and external genitalia. The whole phenomenon is under genetic control and is particularly driven by the presence of the Y chromosome and by the SRY gene, which acts as the key initiator of the early steps of testis determination. However, many other autosomal genes, present in both males and females, are expressed during testis formation in a gene activation pathway, which is far to be totally elucidated. All these genes act in a dosage-sensitive manner by which quantitative gene abnormalities, due to chromosomal deletions, duplications or mosaicism, may lead to testis determination failure and sex reversal.

  9. Temperature dependence of grain boundary free energy and elastic constants

    International Nuclear Information System (INIS)

    Foiles, Stephen M.

    2010-01-01

    This work explores the suggestion that the temperature dependence of the grain boundary free energy can be estimated from the temperature dependence of the elastic constants. The temperature-dependent elastic constants and free energy of a symmetric Σ79 tilt boundary are computed for an embedded atom method model of Ni. The grain boundary free energy scales with the product of the shear modulus times the lattice constant for temperatures up to about 0.75 the melting temperature.

  10. A Temperature-Dependent Hysteresis Model for Relaxor Ferroelectric Compounds

    National Research Council Canada - National Science Library

    Raye, Julie K; Smith, Ralph C

    2004-01-01

    This paper summarizes the development of a homogenized free energy model which characterizes the temperature-dependent hysteresis and constitutive nonlinearities inherent to relaxor ferroelectric materials...

  11. Species identification and sex determination of the genus Nepenthes (Nepenthaceae).

    Science.gov (United States)

    Mokkamul, Piya; Chaveerach, Arunrat; Sudmoon, Runglawan; Tanee, Tawatchai

    2007-02-15

    Nepenthes species are well known for their ornamentally attractive pitchers. The species diversity was randomly surveyed in some conservation areas of Thailand and three species were found, namely N. gracilis Korth., N. mirabilis Druce. and N. smilesii Hemsl. Young plants as unknown species from Chatuchak market were added in plant sampled set. Thirty two Inter Simple Sequence Repeat (ISSR) primers were screened and 13 successful primers were used to produce DNA banding patterns for constructing a dendrogram. The dendrogram is potentially power tool to identify unknown species from Chatuchak market, differentiate species population, population by geographical areas and sex determination. The geographical area of N. mirabilis was specified to Southern and Northeastern regions and finally, subdivided into exact areas according to province. Male and female plants of N. gracilis at Phu Wua Wildlife Sanctuary and N. mirabilis at Bung Khonglong non-hunting area were determined. Two unknown species from Chatuchak market were analyzed to be N. mirabilis with the genetic similarities (S) 77.2 to 84.7. Be more sex specific in all sample studied, 37 Random Amplified Polymorphic DNA (RAPD) primers were investigated. The result shows that only one RAPD primer show high resolution results at about 750 bp specific male-related marker.

  12. Maintenance of polygenic sex determination in a fluctuating environment: an individual-based model.

    Science.gov (United States)

    Bateman, A W; Anholt, B R

    2017-05-01

    R. A. Fisher predicted that individuals should invest equally in offspring of both sexes, and that the proportion of males and females produced (the primary sex ratio) should evolve towards 1:1 when unconstrained. For many species, sex determination is dependent on sex chromosomes, creating a strong tendency for balanced sex ratios, but in other cases, multiple autosomal genes interact to determine sex. In such cases, the maintenance of multiple sex-determining alleles at multiple loci and the consequent among-family variability in sex ratios presents a puzzle, as theory predicts that such systems should be unstable. Theory also predicts that environmental influences on sex can complicate outcomes of genetic sex determination, and that population structure may play a role. Tigriopus californicus, a copepod that lives in splash-pool metapopulations and exhibits polygenic and environment-dependent sex determination, presents a test case for relevant theory. We use this species as a model for parameterizing an individual-based simulation to investigate conditions that could maintain polygenic sex determination. We find that metapopulation structure can delay the degradation of polygenic sex determination and that periods of alternating frequency-dependent selection, imposed by seasonal fluctuations in environmental conditions, can maintain polygenic sex determination indefinitely. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  13. Comparative In silico Study of Sex-Determining Region Y (SRY) Protein Sequences Involved in Sex-Determining.

    Science.gov (United States)

    Vakili Azghandi, Masoume; Nasiri, Mohammadreza; Shamsa, Ali; Jalali, Mohsen; Shariati, Mohammad Mahdi

    2016-04-01

    The SRY gene (SRY) provides instructions for making a transcription factor called the sex-determining region Y protein. The sex-determining region Y protein causes a fetus to develop as a male. In this study, SRY of 15 spices included of human, chimpanzee, dog, pig, rat, cattle, buffalo, goat, sheep, horse, zebra, frog, urial, dolphin and killer whale were used for determine of bioinformatic differences. Nucleotide sequences of SRY were retrieved from the NCBI databank. Bioinformatic analysis of SRY is done by CLC Main Workbench version 5.5 and ClustalW (http:/www.ebi.ac.uk/clustalw/) and MEGA6 softwares. The multiple sequence alignment results indicated that SRY protein sequences from Orcinus orca (killer whale) and Tursiopsaduncus (dolphin) have least genetic distance of 0.33 in these 15 species and are 99.67% identical at the amino acid level. Homosapiens and Pantroglodytes (chimpanzee) have the next lowest genetic distance of 1.35 and are 98.65% identical at the amino acid level. These findings indicate that the SRY proteins are conserved in the 15 species, and their evolutionary relationships are similar.

  14. Comparative In silico Study of Sex-Determining Region Y (SRY Protein Sequences Involved in Sex-Determining

    Directory of Open Access Journals (Sweden)

    Masoume Vakili Azghandi

    2016-05-01

    Full Text Available Background: The SRY gene (SRY provides instructions for making a transcription factor called the sex-determining region Y protein. The sex-determining region Y protein causes a fetus to develop as a male. In this study, SRY of 15 spices included of human, chimpanzee, dog, pig, rat, cattle, buffalo, goat, sheep, horse, zebra, frog, urial, dolphin and killer whale were used for determine of bioinformatic differences. Methods: Nucleotide sequences of SRY were retrieved from the NCBI databank. Bioinformatic analysis of SRY is done by CLC Main Workbench version 5.5 and ClustalW (http:/www.ebi.ac.uk/clustalw/ and MEGA6 softwares. Results: The multiple sequence alignment results indicated that SRY protein sequences from Orcinus orca (killer whale and Tursiopsaduncus (dolphin have least genetic distance of 0.33 in these 15 species and are 99.67% identical at the amino acid level. Homosapiens and Pantroglodytes (chimpanzee have the next lowest genetic distance of 1.35 and are 98.65% identical at the amino acid level. Conclusion: These findings indicate that the SRY proteins are conserved in the 15 species, and their evolutionary relationships are similar.

  15. Temperature dependence of contact resistance at metal/MWNT interface

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Eui; Moon, Kyoung-Seok; Sohn, Yoonchul, E-mail: yoonchul.son@samsung.com [Materials Research Center, Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 443-803 (Korea, Republic of)

    2016-07-11

    Although contact resistance of carbon nanotube (CNT) is one of the most important factors for practical application of electronic devices, a study regarding temperature dependence on contact resistance of CNTs with metal electrodes has not been found. Here, we report an investigation of contact resistance at multiwalled nanotube (MWNT)/Ag interface as a function of temperature, using MWNT/polydimethylsiloxane (PDMS) composite. Electrical resistance of MWNT/PDMS composite revealed negative temperature coefficient (NTC). Excluding the contact resistance with Ag electrode, the NTC effect became less pronounced, showing lower intrinsic resistivity with the activation energy of 0.019 eV. Activation energy of the contact resistance of MWNT/Ag interface was determined to be 0.04 eV, two times larger than that of MWNT-MWNT network. The increase in the thermal fluctuation assisted electron tunneling is attributed to conductivity enhancement at both MWNT/MWNT and MWNT/Ag interfaces with increasing temperature.

  16. Temperature dependency of silicon structures for magnetic field gradient sensing

    Science.gov (United States)

    Dabsch, Alexander; Rosenberg, Christoph; Stifter, Michael; Keplinger, Franz

    2018-02-01

    This work describes the temperature dependence of two sensors for magnetic field gradient sensors and demonstrates a structure to compensate for the drift of resonance frequency over a wide temperature range. The temperature effect of the sensing element is based on internal stresses induced by the thermal expansion of material, therefore FEM is used to determine the change of the eigenvalues of the sensing structure. The experimental setup utilizes a Helmholtz coil system to generate the magnetic field and to excite the MEMS structure with Lorentz forces. The MEMS structure is placed on a plate heated with resistors and cooled by a Peltier element to control the plate temperature. In the second part, we describe how one can exploit temperature sensitivity for temperature measurements and we show the opportunity to include the temperature effect to increase the sensitivity of single-crystal silicon made flux density gradient sensors.

  17. Complementary sex determination substantially increases extinction proneness of haplodiploid populations.

    Science.gov (United States)

    Zayed, Amro; Packer, Laurence

    2005-07-26

    The role of genetic factors in extinction is firmly established for diploid organisms, but haplodiploids have been considered immune to genetic load impacts because deleterious alleles are readily purged in haploid males. However, we show that single-locus complementary sex determination ancestral to the haplodiploid Hymenoptera (ants, bees, and wasps) imposes a substantial genetic load through homozygosity at the sex locus that results in the production of inviable or sterile diploid males. Using stochastic modeling, we have discovered that diploid male production (DMP) can initiate a rapid and previously uncharacterized extinction vortex. The extinction rate in haplodiploid populations with DMP is an order of magnitude greater than in its absence under realistic but conservative demographic parameter values. Furthermore, DMP alone can elevate the base extinction risk in haplodiploids by over an order of magnitude higher than that caused by inbreeding depression in threatened diploids. Thus, contrary to previous expectations, haplodiploids are more, rather than less, prone to extinction for genetic reasons. Our findings necessitate a fundamental shift in approaches to the conservation and population biology of these ecologically and economically crucial insects.

  18. Sex determination in Madagascar geckos of the genus Paroedura (Squamata: Gekkonidae): are differentiated sex chromosomes indeed so evolutionary stable?

    Czech Academy of Sciences Publication Activity Database

    Koubová, M.; Johnson Pokorná, Martina; Rovatsos, M.; Farkačová, K.; Altmanová, M.; Kratochvíl, L.

    2014-01-01

    Roč. 22, č. 4 (2014), s. 441-452 ISSN 0967-3849 R&D Projects: GA ČR GAP506/10/0718 Institutional support: RVO:67985904 Keywords : sex chromosomes * heterochromatin * reptiles * sex determination * FISH * ITSs Subject RIV: EG - Zoology Impact factor: 2.478, year: 2014

  19. Genes involved in sex determination and the influence of ...

    African Journals Online (AJOL)

    As the sex reversal is a highly desired process in fish farming aiming at obtaining male mono-sexual populations (due to weight gain of males), several techniques based on direct and indirect manipulation of phenotypic sex are being tested. Recent surveys show the use of temperature as alternative to the process of sex ...

  20. Temperature-dependent cross sections for meson-meson nonresonant reactions in hadronic matter

    International Nuclear Information System (INIS)

    Zhang Yiping; Xu Xiaoming; Ge Huijun

    2010-01-01

    We present a potential of which the short-distance part is given by one gluon exchange plus perturbative one- and two-loop corrections and of which the large-distance part exhibits a temperature-dependent constant value. The Schroedinger equation with this temperature-dependent potential yields a temperature dependence of the mesonic quark-antiquark relative-motion wave function and of meson masses. The temperature dependence of the potential, the wave function and the meson masses brings about temperature dependence of cross sections for the nonresonant reactions ππ→ρρ for I=2, KK→K*K* for I=1, KK*→K*K* for I=1, πK→ρK* for I=3/2, πK*→ρK* for I=3/2, ρK→ρK* for I=3/2 and πK*→ρK for I=3/2. As the temperature increases, the rise or fall of peak cross sections is determined by the increased radii of initial mesons, the loosened bound states of final mesons, and the total-mass difference of the initial and final mesons. The temperature-dependent cross sections and meson masses are parametrized.

  1. Sex determination in insects: a binary decision based on alternative splicing.

    Science.gov (United States)

    Salz, Helen K

    2011-08-01

    The gene regulatory networks that control sex determination vary between species. Despite these differences, comparative studies in insects have found that alternative splicing is reiteratively used in evolution to control expression of the key sex-determining genes. Sex determination is best understood in Drosophila where activation of the RNA binding protein-encoding gene Sex-lethal is the central female-determining event. Sex-lethal serves as a genetic switch because once activated it controls its own expression by a positive feedback splicing mechanism. Sex fate choice in is also maintained by self-sustaining positive feedback splicing mechanisms in other dipteran and hymenopteran insects, although different RNA binding protein-encoding genes function as the binary switch. Studies exploring the mechanisms of sex-specific splicing have revealed the extent to which sex determination is integrated with other developmental regulatory networks. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Distance and sex determine host plant choice by herbivorous beetles.

    Directory of Open Access Journals (Sweden)

    Daniel J Ballhorn

    Full Text Available Plants respond to herbivore damage with the release of volatile organic compounds (VOCs. This indirect defense can cause ecological costs when herbivores themselves use VOCs as cues to localize suitable host plants. Can VOCs reliably indicate food plant quality to herbivores?We determined the choice behavior of herbivorous beetles (Chrysomelidae: Gynandrobrotica guerreroensis and Cerotoma ruficornis when facing lima bean plants (Fabaceae: Phaseolus lunatus with different cyanogenic potential, which is an important constitutive direct defense. Expression of inducible indirect defenses was experimentally manipulated by jasmonic acid treatment at different concentrations. The long-distance responses of male and female beetles to the resulting induced plant volatiles were investigated in olfactometer and free-flight experiments and compared to the short-distance decisions of the same beetles in feeding trials.Female beetles of both species were repelled by VOCs released from all induced plants independent of the level of induction. In contrast, male beetles were repelled by strongly induced plants, showed no significant differences in choice behavior towards moderately induced plants, but responded positively to VOCs released from little induced plants. Thus, beetle sex and plant VOCs had a significant effect on host searching behavior. By contrast, feeding behavior of both sexes was strongly determined by the cyanogenic potential of leaves, although females again responded more sensitively than males. Apparently, VOCs mainly provide information to these beetles that are not directly related to food quality. Being induced by herbivory and involved in indirect plant defense, such VOCs might indicate the presence of competitors and predators to herbivores. We conclude that plant quality as a food source and finding a potentially enemy-free space is more important for female than for male insect herbivores, whereas the presence of a slightly damaged

  3. Effect of exogenous estradiol applied at different embryonic stages on sex determination, growth, and mortality in the leopard gecko (Eublepharis macularius).

    Science.gov (United States)

    Tousignant, A; Crews, D

    1994-01-01

    Temperature-dependent sex determination (TSD) occurs in three orders of reptiles. Several studies have examined the ability of estradiol to produce female hatchlings incubated at a male-producing temperature. The results of these experiments support the idea that estradiol could be used as a powerful tool in the conservation of endangered species with TSD by manipulating hatchling sex ratios. However, these experiments have concentrated on the mechanism of determination. This experiment was designed to test the efficacy of various dosages of estradiol applied at two different stages to alter the hatchling sex ratio as well as determining the potential use of such manipulation for conservation efforts by monitoring egg mortality and hatchling growth. The leopard gecko (Eublepharis macularius) exhibits TSD and reaches reproductive maturity in less than one year, making it an excellent model for evaluating the long-term effects of estradiol. The results demonstrate that estradiol has a dose-dependent effect on the hatchling sex ratio while only high dosages applied at the later stage of development showed increased mortality. Estrogen-determined females grew at the same rate as temperature-determined females and have produced viable hatchlings. Estradiol treatment of eggs from endangered species may provide a method of insuring female offspring when the TSD pattern is unknown or equipment for controlled incubation is unavailable.

  4. Temperature Dependence in Homogeneous and Heterogeneous Nucleation

    Energy Technology Data Exchange (ETDEWEB)

    McGraw R. L.; Winkler, P. M.; Wagner, P. E.

    2017-08-01

    Heterogeneous nucleation on stable (sub-2 nm) nuclei aids the formation of atmospheric cloud condensation nuclei (CCN) by circumventing or reducing vapor pressure barriers that would otherwise limit condensation and new particle growth. Aerosol and cloud formation depend largely on the interaction between a condensing liquid and the nucleating site. A new paper published this year reports the first direct experimental determination of contact angles as well as contact line curvature and other geometric properties of a spherical cap nucleus at nanometer scale using measurements from the Vienna Size Analyzing Nucleus Counter (SANC) (Winkler et al., 2016). For water nucleating heterogeneously on silver oxide nanoparticles we find contact angles around 15 degrees compared to around 90 degrees for the macroscopically measured equilibrium angle for water on bulk silver. The small microscopic contact angles can be attributed via the generalized Young equation to a negative line tension that becomes increasingly dominant with increasing curvature of the contact line. These results enable a consistent theoretical description of heterogeneous nucleation and provide firm insight to the wetting of nanosized objects.

  5. Birth order, individual sex and sex of competitors determine the outcome of conflict among siblings over parental care

    Science.gov (United States)

    Bonisoli-Alquati, Andrea; Boncoraglio, Giuseppe; Caprioli, Manuela; Saino, Nicola

    2011-01-01

    Success in competition for limiting parental resources depends on the interplay between parental decisions over allocation of care and offspring traits. Birth order, individual sex and sex of competing siblings are major candidates as determinants of success in sib–sib competition, but experimental studies focusing on the combined effect of these factors on parent–offspring communication and within-brood competitive dynamics are rare. Here, we assessed individual food intake and body mass gain during feeding trials in barn swallow chicks differing for seniority and sex, and compared the intensity of their acoustic and postural solicitation (begging) displays. Begging intensity and success in competition depended on seniority in combination with individual sex and sex of the opponent. Junior chicks begged more than seniors, independently of satiation level (which was also experimentally manipulated), and obtained greater access to food. Females were generally weaker competitors than males. Individual sex and sex of the opponent also affected duration of begging bouts. Present results thus show that competition with siblings can make the rearing environment variably harsh for developing chicks, depending on individual sex, sex of competing broodmates and age ranking within the nest. They also suggest that parental decisions on the allocation of care and response of kin to signalling siblings may further contribute to the outcome of sibling competition. PMID:20943688

  6. Fish with thermolabile sex determination (TSD) as models to study brain sex differentiation.

    Science.gov (United States)

    Blázquez, Mercedes; Somoza, Gustavo M

    2010-05-01

    As fish are ectothermic animals, water temperature can affect their basic biological processes such as larval development, growth and reproduction. Similar to reptiles, the incubation temperature during early phases of development is capable to modify sex ratios in a large number of fish species. This phenomenon, known as thermolabile sex determination (TSD) was first reported in Menidia menidia, a species belonging to the family Atherinopsidae. Since then, an increasing number of fish have also been found to exhibit TSD. Traditionally, likewise in reptiles, several TSD patterns have been described in fish, however it has been recently postulated that only one, females at low temperatures and males at high temperatures, may represent the "real" or "true" TSD. Many studies regarding the influence of temperature on the final sex ratios have been focused on the expression and activity of gonadal aromatase, the enzyme involved in the conversion of androgens into estrogens and encoded by the cyp19a1a gene. In this regard, teleost fish, may be due to a whole genome duplication event, produce another aromatase enzyme, commonly named brain aromatase, encoded by the cyp19a1b gene. Contrary to what has been described in other vertebrates, fish exhibit very high levels of aromatase activity in the brain and therefore they synthesize high amounts of neuroestrogens. However, its biological significance is still not understood. In addition, the mechanism whereby temperature can induce the development of a testis or an ovary still remains elusive. In this context the present review is aimed to discuss several theories about the possible role of brain aromatase using fish as models. The relevance of brain aromatase and therefore of neuroestrogens as the possible cue for gonadal differentiation is raised. In addition, the possible role of brain aromatase as the way to keep the high levels of neurogenesis in fish is also considered. Several key examples of how teleosts and aromatase

  7. Evolutionary diversity and turn-over of sex determination in teleost fishes.

    Science.gov (United States)

    Mank, J E; Avise, J C

    2009-01-01

    Sex determination, due to the obvious association with reproduction and Darwinian fitness, has been traditionally assumed to be a relatively conserved trait. However, research on teleost fishes has shown that this need not be the case, as these animals display a remarkable diversity in the ways that they determine sex. These different mechanisms, which include constitutive genetic mechanisms on sex chromosomes, polygenic constitutive mechanisms, environmental influences, hermaphroditism, and unisexuality have each originated numerous independent times in the teleosts. The evolutionary lability of sex determination, and the corresponding rapid rate of turn-over among different modes, makes the teleost clade an excellent model with which to test theories regarding the evolution of sex determining adaptations. Much of the plasticity in sex determination likely results from the dynamic teleost genome, and recent advances in fish genetics and genomics have revealed the role of gene and genome duplication in fostering emergence and turn-over of sex determining mechanisms. 2009 S. Karger AG, Basel.

  8. Sex determination in honeybees: two separate mechanisms induce and maintain the female pathway

    DEFF Research Database (Denmark)

    Gempe, Tanja; Hasselmann, Martin; Schiøtt, Morten

    2009-01-01

    Organisms have evolved a bewildering diversity of mechanisms to generate the two sexes. The honeybee (Apis mellifera) employs an interesting system in which sex is determined by heterozygosity at a single locus (the Sex Determination Locus) harbouring the complementary sex determiner (csd) gene....... Bees heterozygous at Sex Determination Locus are females, whereas bees homozygous or hemizygous are males. Little is known, however, about the regulation that links sex determination to sexual differentiation. To investigate the control of sexual development in honeybees, we analyzed the functions...... and the regulatory interactions of genes involved in the sex determination pathway. We show that heterozygous csd is only required to induce the female pathway, while the feminizer (fem) gene maintains this decision throughout development. By RNAi induced knockdown we show that the fem gene is essential for entire...

  9. Sex determination in Madagascar geckos of the genus Paroedura (Squamata: Gekkonidae): are differentiated sex chromosomes indeed so evolutionary stable?

    Science.gov (United States)

    Koubová, Martina; Johnson Pokorná, Martina; Rovatsos, Michail; Farkačová, Klára; Altmanová, Marie; Kratochvíl, Lukáš

    2014-12-01

    Among amniote vertebrates, geckos represent a clade with exceptional variability in sex determination; however, only a minority of species of this highly diverse group has been studied in this respect. Here, we describe for the first time a female heterogamety in the genus Paroedura, the group radiated in Madagascar and adjacent islands. We identified homomorphic ZZ/ZW sex chromosomes with a highly heterochromatic W chromosome in Paroedura masobe, Paroedura oviceps, Paroedura karstophila, Paroedura stumpffi, and Paroedura lohatsara. Comparative genomic hybridization (CGH) revealed that female-specific sequences are greatly amplified in the W chromosome of P. lohatsara and that P. gracilis seems to possess a derived system of multiple sex chromosomes. Contrastingly, neither CGH nor heterochromatin visualization revealed differentiated sex chromosomes in the members of the Paroedura picta-Paroedura bastardi-Paroedura ibityensis clade, which is phylogenetically nested within lineages with a heterochromatic W chromosome. As a sex ratio consistent with genotypic sex determination has been reported in P. picta, it appears that the members of the P. picta-P. bastardi-P. ibityensis clade possess homomorphic, poorly differentiated sex chromosomes and may represent a rare example of evolutionary loss of highly differentiated sex chromosomes. Fluorescent in situ hybridization (FISH) with a telomeric probe revealed a telomere-typical pattern in all species and an accumulation of telomeric sequences in the centromeric region of autosomes in P. stumpffi and P. bastardi. Our study adds important information for the greater understanding of the variability and evolution of sex determination in geckos and demonstrates how the geckos of the genus Paroedura provide an interesting model for studying the evolution of the sex chromosomes.

  10. Temperature dependence of LRE-HRE-TM thin films

    Science.gov (United States)

    Li, Zuoyi; Cheng, Xiaomin; Lin, Gengqi; Li, Zhen; Huang, Zhixin; Jin, Fang; Wang, Xianran; Yang, Xiaofei

    2003-04-01

    Temperature dependence of the properties of RE-TM thin films is very important for MO recording. In this paper, we studied the temperature dependence of the magnetic and magneto-optical properties of the amorphous LRE-HRE-TM single layer thin films and LRE-HRE-TM/HRE-TM couple-bilayered thin films. For LRE-HRE-TM single layer thin films, the temperature dependence of the magnetization was investigated by using the mean field theory. The experimental and theoretical results matched very well. With the LRE substitution in HRE-TM thin film, the compensation temperature Tcomp decreased and the curie temperature Tc remained unchanged. Kerr rotation angle became larger and the saturation magnetization Ms at room temperature increased. For LRE-HRE-TM/HRE-TM couple-bilayered thin films, comparisons of the temperature dependences of the coercivities and Kerr rotation angles were made between isolated sublayers and couple-bilayered thin film.

  11. Temperature dependence of the magnetization of canted spin structures

    DEFF Research Database (Denmark)

    Jacobsen, Henrik; Lefmann, Kim; Brok, Erik

    2012-01-01

    Numerous studies of the low-temperature saturation magnetization of ferrimagnetic nanoparticles and diamagnetically substituted ferrites have shown an anomalous temperature dependence. It has been suggested that this is related to freezing of canted magnetic structures. We present models for the ......Numerous studies of the low-temperature saturation magnetization of ferrimagnetic nanoparticles and diamagnetically substituted ferrites have shown an anomalous temperature dependence. It has been suggested that this is related to freezing of canted magnetic structures. We present models...... for the temperature dependence of the magnetization of a simple canted spin structure in which relaxation can take place at finite temperatures between spin configurations with different canting angles. We show that the saturation magnetization may either decrease or increase with decreasing temperature, depending...

  12. Impact and determinants of sex preference in Nepal.

    Science.gov (United States)

    Leone, Tiziana; Matthews, Zoë; Dalla Zuanna, Gianpiero

    2003-06-01

    Gender discrimination and son preference are key demographic features of South Asia and are well documented for India. However, gender bias and sex preference in Nepal have received little attention. 1996 Nepal Demographic and Health Survey data on ever-married women aged 15-49 who did not desire any more children were used to investigate levels of gender bias and sex preference. The level of contraceptive use and the total fertility rate in the absence of sex preference were estimated, and logistic regression was performed to analyze the association between socioeconomic and demographic variables and stopping childbearing after the birth of a son. Commonly used indicators of gender bias, such as sex ratio at birth and sex-specific immunization rates, do not suggest a high level of gender discrimination in Nepal. However, sex preference decreases contraceptive use by 24% and increases the total fertility rate by more than 6%. Women's contraceptive use, exposure to the media, parity, last birth interval, educational level and religion are linked to stopping childbearing after the birth of a boy, as is the ethnic makeup of the local area. The level of sex preference in Nepal is substantial. Sex preference is an important barrier to the increase of contraceptive use and decline of fertility in the country; its impact will be greater as desired family size declines.

  13. Temperature dependence of 1H NMR chemical shifts and its influence on estimated metabolite concentrations.

    Science.gov (United States)

    Wermter, Felizitas C; Mitschke, Nico; Bock, Christian; Dreher, Wolfgang

    2017-12-01

    Temperature dependent chemical shifts of important brain metabolites measured by localised 1 H MRS were investigated to test how the use of incorrect prior knowledge on chemical shifts impairs the quantification of metabolite concentrations. Phantom measurements on solutions containing 11 metabolites were performed on a 7 T scanner between 1 and 43 °C. The temperature dependence of the chemical shift differences was fitted by a linear model. Spectra were simulated for different temperatures and analysed by the AQSES program (jMRUI 5.2) using model functions with chemical shift values for 37 °C. Large differences in the temperature dependence of the chemical shift differences were determined with a maximum slope of about ±7.5 × 10 -4  ppm/K. For 32-40 °C, only minor quantification errors resulted from using incorrect chemical shifts, with the exception of Cr and PCr. For 1-10 °C considerable quantification errors occurred if the temperature dependence of the chemical shifts was neglected. If 1 H MRS measurements are not performed at 37 °C, for which the published chemical shift values have been determined, the temperature dependence of chemical shifts should be considered to avoid systematic quantification errors, particularly for measurements on animal models at lower temperatures.

  14. Temperature dependence of sound velocity in yttrium ferrite

    International Nuclear Information System (INIS)

    L'vov, V.A.

    1979-01-01

    The effect of the phonon-magnon and phonon-phonon interoctions on the temperature dependence of the longitudinal sound velocity in yttrium ferrite is considered. It has been shown that at low temperatures four-particle phonon-magnon processes produce the basic contribution to renormalization of the sound velocity. At higher temperatures the temperature dependence of the sound velocity is mainly defined by phonon-phonon processes

  15. Identification of temperature-dependent thermal conductivity and experimental verification

    International Nuclear Information System (INIS)

    Pan, Weizhen; Yi, Fajun; Zhu, Yanwei; Meng, Songhe

    2016-01-01

    A modified Levenberg–Marquardt method (LMM) for the identification of temperature-dependent thermal conductivity is proposed; the experiment and structure of the specimen for identification are also designed. The temperature-dependent thermal conductivities of copper C10200 and brass C28000 are identified to verify the effectiveness of the proposed identification method. The comparison between identified results and the measured data of laser flash diffusivity apparatus indicates the fine consistency and potential usage of the proposed method. (paper)

  16. What was the ancestral sex-determining mechanism in amniote vertebrates?

    Science.gov (United States)

    Johnson Pokorná, Martina; Kratochvíl, Lukáš

    2016-02-01

    Amniote vertebrates, the group consisting of mammals and reptiles including birds, possess various mechanisms of sex determination. Under environmental sex determination (ESD), the sex of individuals depends on the environmental conditions occurring during their development and therefore there are no sexual differences present in their genotypes. Alternatively, through the mode of genotypic sex determination (GSD), sex is determined by a sex-specific genotype, i.e. by the combination of sex chromosomes at various stages of differentiation at conception. As well as influencing sex determination, sex-specific parts of genomes may, and often do, develop specific reproductive or ecological roles in their bearers. Accordingly, an individual with a mismatch between phenotypic (gonadal) and genotypic sex, for example an individual sex-reversed by environmental effects, should have a lower fitness due to the lack of specialized, sex-specific parts of their genome. In this case, evolutionary transitions from GSD to ESD should be less likely than transitions in the opposite direction. This prediction contrasts with the view that GSD was the ancestral sex-determining mechanism for amniote vertebrates. Ancestral GSD would require several transitions from GSD to ESD associated with an independent dedifferentiation of sex chromosomes, at least in the ancestors of crocodiles, turtles, and lepidosaurs (tuataras and squamate reptiles). In this review, we argue that the alternative theory postulating ESD as ancestral in amniotes is more parsimonious and is largely concordant with the theoretical expectations and current knowledge of the phylogenetic distribution and homology of sex-determining mechanisms. © 2014 Cambridge Philosophical Society.

  17. Evidence of oligogenic sex determination in the apple snail Pomacea canaliculata.

    Science.gov (United States)

    Yusa, Yoichi; Kumagai, Natsumi

    2018-02-26

    A small number of genes may interact to determine sex, but few such examples have been demonstrated in animals, especially through comprehensive mating experiments. The highly invasive apple snail Pomacea canaliculata is gonochoristic and shows a large variation in brood sex ratio, and the involvement of multiple genes has been suggested for this phenomenon. We conducted mating experiments to determine whether their sex determination involves a few or many genes (i.e., oligogenic or polygenic sex determination, respectively). Full-sib females or males that were born from the same parents were mated to an adult of the opposite sex, and the brood sex ratios of the parents and their offspring were investigated. Analysis of a total of 4288 offspring showed that the sex ratios of offspring from the full-sib females were variable but clustered into only a few values. Similar patterns were observed for the full-sib males, although the effect was less clear because fewer offspring were used (n = 747). Notably, the offspring sex ratios of all full-sib females in some families were nearly 0.5 (proportion of males) with little variation. These results indicate that the number of genotypes of the full-sibs, and hence genes involved in sex determination, is small in this snail. Such oligogenic systems may be a major sex-determining system among animals, especially those with variable sex ratios.

  18. Feedback Control of Sex Determination by Dosage Compensation Revealed through Caenorhabditis Elegans Sdc-3 Mutations

    OpenAIRE

    DeLong, L.; Plenefisch, J. D.; Klein, R. D.; Meyer, B. J.

    1993-01-01

    In Caenorhabditis elegans, sex determination and dosage compensation are coordinately controlled through a group of genes that respond to the primary sex determination signal. Here we describe a new gene, sdc-3, that also controls these processes. In contrast to previously described genes, the sex determination and dosage compensation activities of sdc-3 are separately mutable, indicating that they function independently. Paradoxically, the sdc-3 null phenotype fails to reveal the role of sdc...

  19. Did Lizards Follow Unique Pathways in Sex Chromosome Evolution?

    Science.gov (United States)

    Gleeson, Dianne; Georges, Arthur

    2018-01-01

    Reptiles show remarkable diversity in modes of reproduction and sex determination, including high variation in the morphology of sex chromosomes, ranging from homomorphic to highly heteromorphic. Additionally, the co-existence of genotypic sex determination (GSD) and temperature-dependent sex determination (TSD) within and among sister clades makes this group an attractive model to study and understand the evolution of sex chromosomes. This is particularly so with Lizards (Order Squamata) which, among reptiles, show extraordinary morphological diversity. They also show no particular pattern of sex chromosome degeneration of the kind observed in mammals, birds and or even in snakes. We therefore speculate that sex determination sensu sex chromosome evolution is labile and rapid and largely follows independent trajectories within lizards. Here, we review the current knowledge on the evolution of sex chromosomes in lizards and discuss how sex chromosome evolution within that group differs from other amniote taxa, facilitating unique evolutionary pathways. PMID:29751579

  20. Did Lizards Follow Unique Pathways in Sex Chromosome Evolution?

    Directory of Open Access Journals (Sweden)

    Shayer Mahmood Ibney Alam

    2018-05-01

    Full Text Available Reptiles show remarkable diversity in modes of reproduction and sex determination, including high variation in the morphology of sex chromosomes, ranging from homomorphic to highly heteromorphic. Additionally, the co-existence of genotypic sex determination (GSD and temperature-dependent sex determination (TSD within and among sister clades makes this group an attractive model to study and understand the evolution of sex chromosomes. This is particularly so with Lizards (Order Squamata which, among reptiles, show extraordinary morphological diversity. They also show no particular pattern of sex chromosome degeneration of the kind observed in mammals, birds and or even in snakes. We therefore speculate that sex determination sensu sex chromosome evolution is labile and rapid and largely follows independent trajectories within lizards. Here, we review the current knowledge on the evolution of sex chromosomes in lizards and discuss how sex chromosome evolution within that group differs from other amniote taxa, facilitating unique evolutionary pathways.

  1. The temperature dependences of electromechanical properties of PLZT ceramics

    Science.gov (United States)

    Czerwiec, M.; Zachariasz, R.; Ilczuk, J.

    2008-02-01

    The mechanical and electrical properties in lanthanum modified lead zirconate-titanate ceramics of 5/50/50 and 10/50/50 were studied by mechanical loss Q - 1, Young's modulus E, electric permittivity ɛ and tangent of dielectric loss of angle tgδ measurements. The internal friction Q - 1 and Young modulus E measured from 290 K to 600 K shows that Curie temperature TC is located at 574 K and 435 K (1st cycle of heating) respectively for ceramic samples 5/50/50 and 10/50/50. The movement of TC in second cycle of heating to lower temperature (561 K for 5/50/50 and 420 K for 10/50/50) has been observed. Together with Q - 1 and E measurements, temperature dependences of ɛ=f(T) and tgδ=f(T) were determinated in temperature range from 300 K to 730 K. The values of TC obtained during ɛ and tgδ measurements were respectively: 560 K for 5/50/50 and 419 K for 10/50/50. These temperatures are almost as high as the temperatures obtained by internal friction Q - 1 measurements in second cycle of heating. In ceramic sample 10/50/50 the additional maximum on internal friction Q - 1 curve at the temperature 316 K was observed.

  2. Temperature dependent kinematic viscosity of different types of engine oils

    Directory of Open Access Journals (Sweden)

    Libor Severa

    2009-01-01

    Full Text Available The objective of this study is to measure how the viscosity of engine oil changes with temperature. Six different commercially distributed engine oils (primarily intended for motorcycle engines of 10W–40 viscosity grade have been evaluated. Four of the oils were of synthetic type, two of semi–synthetic type. All oils have been assumed to be Newtonian fluids, thus flow curves have not been determined. Oils have been cooled to below zero temperatures and under controlled temperature regulation, kinematic viscosity (mm2 / s have been measured in the range of −5 °C and +115 °C. Anton Paar digital viscometer with concentric cylinders geometry has been used. In accordance with expected behavior, kinematic viscosity of all oils was decreasing with increasing temperature. Viscosity was found to be independent on oil’s density. Temperature dependence has been modeled using se­ve­ral mathematical models – Vogel equation, Arrhenius equation, polynomial, and Gaussian equation. The best match between experimental and computed data has been achieved for Gaussian equation (R2 = 0.9993. Knowledge of viscosity behavior of an engine oil as a function of its temperature is of great importance, especially when considering running efficiency and performance of combustion engines. Proposed models can be used for description and prediction of rheological behavior of engine oils.

  3. Sex determination using free fetal DNA in early pregnancy: With the approach to sex linked recessive disorders

    Directory of Open Access Journals (Sweden)

    Amir Monfaredan

    2017-03-01

    Full Text Available Introduction: Prenatal diagnosis is testing for detection of diseases or conditions in a fetus or embryo before it is born. Most of prenatal diagnostic (PD techniques are invasive and done in late stages of pregnancy. Using fetal DNA in maternal blood for fetal sex determination in early pregnancy might help in management of X-linked genetic diseases. This study aimed to investigate the accuracy of sex determination using fetal DNA in maternal blood at 8-12 weeks of gestation. Methods: In this cross-sectional study, 30 pregnant women at 8-12 weeks of gestation were enrolled. The sex-determining region Y (SRY gene expression with the internal control (IC glyceraldehyde 3-phosphate dehydrogenase (GAPDH was investigated with quantitative real-time polymerase chain reaction (PCR using specific primers and probes. Results: Accuracy of sex determination with SRY gene expression in 8-12 weeks of pregnancy were 85%, 85%, 90% and 100% respectively. Conclusion: It seems that fetal sex determining using fetal DNA in maternal blood is a reliable method for early stage of pregnancy.

  4. Sex determination of duck embryos: observations on syrinx development

    Science.gov (United States)

    Wilson, Robert E.; Sonsthagen, Sarah A.; Franson, J. Christian

    2013-01-01

    Ducks exhibit sexual dimorphism in vocal anatomy. Asymmetrical ossification of the syrinx (bulla syringealis) is discernable at about 10 days of age in male Pekin duck (Anas platyrhynchos domestica) embryos, but information is lacking on the early development of the bulla in wild ducks. To evaluate the reliability of this characteristic for sexing developing embryos, we examined the syrinx of dead embryos and compared results with molecular sexing techniques in high arctic nesting Common Eiders (Somateria mollissima). Embryos 8 days or older were accurately (100%) sexed based on the presence/absence of a bulla, 2 days earlier than Pekin duck. The use of the tracheal bulla can be a valuable technique when sex identification of embryos or young ducklings is required.

  5. Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach

    Science.gov (United States)

    Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

    2013-01-01

    Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

  6. Sex and ancestry determine the free-running circadian period.

    Science.gov (United States)

    Eastman, Charmane I; Tomaka, Victoria A; Crowley, Stephanie J

    2017-10-01

    The endogenous, free-running circadian period (τ) determines the phase relationship that an organism assumes when entrained to the 24-h day. We found a shorter circadian period in African Americans compared to non-Hispanic European Americans (24.07 versus 24.33 h). We speculate that a short circadian period, closer to 24 h, was advantageous to humans living around the equator, but when humans migrated North out of Africa, where the photoperiod changes with seasons, natural selection favoured people with longer circadian periods. Recently, in evolutionary terms, immigrants came from Europe and Africa to America ('the New World'). The Europeans were descendents of people who had lived in Europe for thousands of years with changing photoperiods (and presumably longer periods), whereas Africans had ancestors who had always lived around the equator (with shorter periods). It may have been advantageous to have a longer circadian period while living in Europe early in the evolution of humans. In our modern world, however, it is better to have a shorter period, because it helps make our circadian rhythms earlier, which is adaptive in our early-bird-dominated society. European American women had a shorter circadian period than men (24.24 versus 24.41), but there was no sex difference in African Americans (24.07 for both men and women). We speculate that selection pressures in Europe made men develop a slightly longer period than women to help them track dawn which could be useful for hunters, but less important for women as gatherers. © 2017 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.

  7. Determinants of Heterosexual Adolescents Having Sex with Female Sex Workers in Singapore.

    Directory of Open Access Journals (Sweden)

    Junice Y S Ng

    Full Text Available We assessed the proportion of and socio-ecological factors associated with ever having had sex with female sex workers (FSWs among heterosexual adolescents. We also described the characteristics of the adolescents who reported inconsistent condom use with FSWs.This is a cross-sectional study (response rate: 73% of 300 heterosexually active male adolescents of 16 to 19 years attending a national STI clinic in Singapore between 2009 and 2014. We assessed the ecological factors (individual, parental, peer, school and medial influences and sexual risk behaviors using a self-reported questionnaire. Poisson regression was used to obtain the adjusted prevalence ratios (aPR and confidence intervals (CI.The proportion of heterosexual male adolescents who had ever had sex with FSWs was 39%. Multivariate analysis showed that significant factors associated with ever having had sex with FSWs were sex initiation before 16 years old (aPR 1.79 CI: 1.30-2.46, never had a sexually active girlfriend (aPR 1.75 CI 1.28-2.38, reported lower self-esteem score (aPR 0.96 CI: 0.93-0.98, higher rebelliousness score (aPR 1.03 CI: 1.00-1.07 and more frequent viewing of pornography (aPR 1.47 CI: 1.04-2.09. Lifetime inconsistent condom use with FSWs was 30%.A significant proportion of heterosexual male adolescents attending the public STI clinic had ever had sex with FSWs. A targeted intervention that addresses different levels of influence to this behavior is needed. This is even more so because a considerable proportion of adolescents reported inconsistent condom use with FSWs, who may serve as a bridge of STI transmission to the community. National surveys on adolescent health should include the assessment of frequency of commercial sex visits and condom use with FSWs for long-term monitoring and surveillance.

  8. Temperature dependence of three-body ion-molecule reactions

    International Nuclear Information System (INIS)

    Boehringer, H.; Arnold, F.

    1983-01-01

    The temperature dependence of the ion-molecule association reactions (i) N 2 + + N 2 + M → N 4 + + M (M=N 2 , He), (ii) O 2 + + O 2 + M → O 4 + + M (M=O 2 , He) and (iii) He + + 2He → He 2 + + He have been studied over an extended temperature range to temperatures as low as 30K with a recently constructed liquid helium-cooled ion drift tube. Over most of the temperature range the threebody reaction rate coefficients show an inverse temperature dependence proportional to Tsup(-n) with n in the range 0.6 to 2.9. This temperature dependence is quite consistent with current theories of ion molecule association. At low temperatures, however, a deviation from the Tsup(-n) dependence was observed for the association reactions (ii). For reactions (i) different temperature dependences were obtained for N 2 and He third bodies indicating an additional temperature dependence of the collisional stabilisation process. (Authors)

  9. Theory of temperature dependent photoemission spectrum of heavy fermion semiconductors

    International Nuclear Information System (INIS)

    Riseborough, P.S.

    1998-01-01

    The heavy fermion semiconductors are a class of strongly correlated materials, that at high temperatures show properties similar to those of heavy fermion materials, but at low temperatures show a cross-over into a semi-conducting state. The low temperature insulating state is characterized by an anomalously small energy gap, varying between 10 and 100 K. The smallness of the gap is attributed to the result of a many-body renormalization, and is temperature dependent. The temperature dependence of the electronic spectral density of states is calculated, using the Anderson lattice model at half filling. The spectrum is calculated to second order in 1/N, where N is the degeneracy of the 'f' orbitals, using a slave boson technique. The system is an indirect gap semi-conductor, with an extremely temperature dependent electronic spectral density A(k, ω). The indirect gap is subject to a temperature dependent many-body renormalization, and leads to a sharp temperature dependent structure in the angle resolved photo-emission spectrum at the indirect threshold. The theoretical predictions are compared with experimental observations on FeSi. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

  10. Sex determination from the frontal bone: a geometric morphometric study.

    Science.gov (United States)

    Perlaza, Néstor A

    2014-09-01

    Sex estimation in human skeletal remains when using the cranium through traditional methods is a fundamental pillar in human identification; however, it may be possible to incur in a margin of error due because of the state of preservation in incomplete or fragmented remains. The aim of this investigation was sex estimation through the geometric morphometric analysis of the frontal bone. The sample employed 60 lateral radiographs of adult subjects of both sexes (30 males and 30 females), aged between 18 and 40 years, with mean age for males of 28 ± 4 and 30 ± 6 years for females. Thin-plate splines evidenced strong expansion of the glabellar region in males and contraction in females. No significant differences were found between sexes with respect to size. The findings suggest differences in shape and size in the glabellar region, besides reaffirming the use of geometric morphometrics as a quantitative method in sex estimation. © 2014 American Academy of Forensic Sciences.

  11. Observed and simulated temperature dependence of the liquid water path of low clouds

    Energy Technology Data Exchange (ETDEWEB)

    Del Genio, A.D.; Wolf, A.B. [NASA Goddard Institute for Space Studies, New York, NY (United States)

    1996-04-01

    Data being acquired at the Atmospheric Radiation Measurement (ARM) Southern great Plains (SGP) Cloud and Radiation Testbed (CART) site can be used to examine the factors determining the temperature dependence of cloud optical thickness. We focus on cloud liquid water and physical thickness variations which can be derived from existing ARM measurements.

  12. A simple equation for describing the temperature dependent growth of free-floating macrophytes

    NARCIS (Netherlands)

    Heide, van Tj.; Roijackers, R.M.M.; Nes, van E.H.; Peeters, E.T.H.M.

    2006-01-01

    Temperature is one of the most important factors determining growth rates of free-floating macrophytes in the field. To analyse and predict temperature dependent growth rates of these pleustophytes, modelling may play an important role. Several equations have been published for describing

  13. Energy based model for temperature dependent behavior of ferromagnetic materials

    International Nuclear Information System (INIS)

    Sah, Sanjay; Atulasimha, Jayasimha

    2017-01-01

    An energy based model for temperature dependent anhysteretic magnetization curves of ferromagnetic materials is proposed and benchmarked against experimental data. This is based on the calculation of macroscopic magnetic properties by performing an energy weighted average over all possible orientations of the magnetization vector. Most prior approaches that employ this method are unable to independently account for the effect of both inhomogeneity and temperature in performing the averaging necessary to model experimental data. Here we propose a way to account for both effects simultaneously and benchmark the model against experimental data from ~5 K to ~300 K for two different materials in both annealed (fewer inhomogeneities) and deformed (more inhomogeneities) samples. This demonstrates that this framework is well suited to simulate temperature dependent experimental magnetic behavior. - Highlights: • Energy based model for temperature dependent ferromagnetic behavior. • Simultaneously accounts for effect of temperature and inhomogeneities. • Benchmarked against experimental data from 5 K to 300 K.

  14. Exploring the envelope. Systematic alteration in the sex-determination system of the nematode caenorhabditis elegans.

    OpenAIRE

    Hodgkin, Jonathan

    2002-01-01

    The natural sexes of the nematode Caenorhabditis elegans are the self-fertilizing hermaphrodite (XX) and the male (XO). The underlying genetic pathway controlling sexual phenotype has been extensively investigated. Mutations in key regulatory genes have been used to create a series of stable populations in which sex is determined not by X chromosome dosage, but in a variety of other ways, many of which mimic the diverse sex-determination systems found in different animal species. Most of thes...

  15. Temperature dependent charge transport in poly(3-hexylthiophene) diodes

    Science.gov (United States)

    Rahaman, Abdulla Bin; Sarkar, Atri; Banerjee, Debamalya

    2018-04-01

    In this work, we present charge transport properties of poly(3-hexylthiophene) (P3HT) diodes under dark conditions. Temperature dependent current-voltage (J-V) characteristics shows that charge transport represents a transition from ohomic to trap limited current. The forward current density obeys a power law J˜Vm, m>2 represents the space charge limited current region in presence of traps within the band gap. Frequency dependent conductivity has been studied in a temperature range 150K-473K. The dc conductivity values show Arrhenius like behavior and it gives conductivity activation energy 223 meV. Temperature dependent conductivity indicates a thermodynamic transition of our system.

  16. The temperature dependent amide I band of crystalline acetanilide

    International Nuclear Information System (INIS)

    Cruzeiro, Leonor; Freedman, Holly

    2013-01-01

    The temperature dependent anomalous peak in the amide I band of crystalline acetanilide is thought to be due to self-trapped states. On the contrary, according to the present model, the anomalous peak comes from the fraction of ACN molecules strongly hydrogen-bonded to a neighboring ACN molecule, and its intensity decreases because, on average, this fraction decreases as temperature increases. This model provides, for the first time, an integrated and theoretically consistent view of the temperature dependence of the full amide I band and a qualitative explanation of some of the features of nonlinear pump–probe experiments.

  17. The temperature dependent amide I band of crystalline acetanilide

    Energy Technology Data Exchange (ETDEWEB)

    Cruzeiro, Leonor [CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Physics Department, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Freedman, Holly [CCMAR, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2013-10-01

    The temperature dependent anomalous peak in the amide I band of crystalline acetanilide is thought to be due to self-trapped states. On the contrary, according to the present model, the anomalous peak comes from the fraction of ACN molecules strongly hydrogen-bonded to a neighboring ACN molecule, and its intensity decreases because, on average, this fraction decreases as temperature increases. This model provides, for the first time, an integrated and theoretically consistent view of the temperature dependence of the full amide I band and a qualitative explanation of some of the features of nonlinear pump–probe experiments.

  18. The temperature dependent amide I band of crystalline acetanilide

    Science.gov (United States)

    Cruzeiro, Leonor; Freedman, Holly

    2013-10-01

    The temperature dependent anomalous peak in the amide I band of crystalline acetanilide is thought to be due to self-trapped states. On the contrary, according to the present model, the anomalous peak comes from the fraction of ACN molecules strongly hydrogen-bonded to a neighboring ACN molecule, and its intensity decreases because, on average, this fraction decreases as temperature increases. This model provides, for the first time, an integrated and theoretically consistent view of the temperature dependence of the full amide I band and a qualitative explanation of some of the features of nonlinear pump-probe experiments.

  19. Children's Physical Attractiveness and Sex as Determinants of Adult Punitiveness

    Science.gov (United States)

    Dion, Karen K.

    1974-01-01

    Two studies investigated the influence of a child's physical attractiveness and sex as potential elicitors of differential adult punitiveness. Assessed were the reactions of 40 women and 44 men. Results reveal differences in men's and women's reactions and suggest differences in their orientation towards children's task behavior. (Author/SDH)

  20. Determinant Factors of Attitude towards Quantitative Subjects: Differences between Sexes

    Science.gov (United States)

    Mondejar-Jimenez, Jose; Vargas-Vargas, Manuel

    2010-01-01

    Nowadays, almost all curricula in the social sciences contain at least one course in statistics, given the importance of this discipline as an analytical tool. This work identifies the latent factors relating to students' motivation and attitude towards statistics, tests their covariance structure for samples of both sexes, and identifies the…

  1. Finding clues to the riddle of sex determination in zebrafish

    Indian Academy of Sciences (India)

    ... to instruct retention of the ovarian fate. The mechanism and identity of this instructive signal remain unknown. We hypothesize that sex in zebrafish is a culmination of combinatorial effects of the genome, germ cells and the environment with inputs from epigenetic factors translating the biological meaning of this interaction.

  2. Genes involved in sex determination process and the influence of ...

    African Journals Online (AJOL)

    DR. & MRS. TONY A. NLEWADIM

    2013-04-24

    Apr 24, 2013 ... sex reversal from females to males in many fish species is the use of steroid ...... functional males under 18°C (between 42 and 151 dpf). Craig et al. (1996) ..... Ecology meets endocrinology: ..... Phylogeny, expression and ...

  3. A new component of the Nasonia sex determining cascade is maternally silenced and regulates transformer expression.

    Science.gov (United States)

    Verhulst, Eveline C; Lynch, Jeremy A; Bopp, Daniel; Beukeboom, Leo W; van de Zande, Louis

    2013-01-01

    Although sex determination is a universal process in sexually reproducing organisms, sex determination pathways are among the most highly variable genetic systems found in nature. Nevertheless, general principles can be identified among the diversity, like the central role of transformer (tra) in insects. When a functional TRA protein is produced in early embryogenesis, the female sex determining route is activated, while prevention of TRA production leads to male development. In dipterans, male development is achieved by prevention of female-specific splicing of tra mRNA, either mediated by X-chromosome dose or masculinizing factors. In Hymenoptera, which have haplodiploid sex determination, complementary sex determination and maternal imprinting have been identified to regulate timely TRA production. In the parasitoid Nasonia, zygotic transformer (Nvtra) expression and splicing is regulated by a combination of maternal provision of Nvtra mRNA and silencing of Nvtra expression in unfertilized eggs. It is unclear, however, if this silencing is directly on the tra locus or whether it is mediated through maternal silencing of a trans-acting factor. Here we show that in Nasonia, female sex determination is dependent on zygotic activation of Nvtra expression by an as yet unknown factor. This factor, which we propose to term womanizer (wom), is maternally silenced during oogenesis to ensure male development in unfertilized eggs. This finding implicates the upstream recruitment of a novel gene in the Nasonia sex determining cascade and supports the notion that sex determining cascades can rapidly change by adding new components on top of existing regulators.

  4. Absence of complementary sex determination in the parasitoid wasp genus asobara (hymenoptera: braconidae)

    NARCIS (Netherlands)

    Ma, W.J.; Kuijper, B.; Boer, de J.G.; Zande, van de L.; Beukeboom, L.W.; Wertheim, B.; Pannebakker, B.A.

    2013-01-01

    An attractive way to improve our understanding of sex determination evolution is to study the underlying mechanisms in closely related species and in a phylogenetic perspective. Hymenopterans are well suited owing to the diverse sex determination mechanisms, including different types of

  5. Absence of complementary sex determination in the parasitoid wasp genus Asobara (Hymenoptera: Braconidae)

    NARCIS (Netherlands)

    Ma, Wen-Juan; Kuijper, Bram; de Boer, Jetske G.; van de Zande, Louis; Beukeboom, Leo W.; Wertheim, Bregje; Pannebakker, Bart A.

    2013-01-01

    An attractive way to improve our understanding of sex determination evolution is to study the underlying mechanisms in closely related species and in a phylogenetic perspective. Hymenopterans are well suited owing to the diverse sex determination mechanisms, including different types of

  6. Single-locus complementary sex determination in the inbreeding wasp Euodynerus foraminatus Saussure (Hymenoptera: Vespidae).

    Science.gov (United States)

    Stahlhut, J K; Cowan, D P

    2004-03-01

    The Hymenoptera have arrhenotokous haplodiploidy in which males normally develop from unfertilized eggs and are haploid, while females develop from fertilized eggs and are diploid. Multiple sex determination systems are known to underlie haplodiploidy, and the best understood is single-locus complementary sex determination (sl-CSD) in which sex is determined at a single polymorphic locus. Individuals heterozygous at the sex locus develop as females; individuals that are hemizygous (haploid) or homozygous (diploid) at the sex locus develop as males. sl-CSD can be detected with inbreeding experiments that produce diploid males in predictable proportions as well as sex ratio shifts due to diploid male production. This sex determination system is considered incompatible with inbreeding because the ensuing increase in homozygosity increases the production of diploid males that are inviable or infertile, imposing a high cost on matings between close relatives. However, in the solitary hunting wasp Euodynerus foraminatus, a species suspected of having sl-CSD, inbreeding may be common due to a high incidence of sibling matings at natal nests. In laboratory crosses with E. foraminatus, we find that sex ratios and diploid male production (detected as microsatellite heterozygosity) are consistent with sl-CSD, but not with other sex determination systems. This is the first documented example of sl-CSD in a hymenopteran with an apparent natural history of inbreeding, and thus presents a paradox for our understanding of hymenopteran genetics.

  7. Electronically induced nuclear transitions - temperature dependence and Rabi oscillations

    International Nuclear Information System (INIS)

    Niez, J.J.

    2002-01-01

    This paper deals with a nucleus electromagnetically coupled with the bound states of its electronic surroundings. It describes the temperature dependence of its dynamics and the onset of potential Rabi oscillations by means of a Master Equation. The latter is generalized in order to account for possible strong resonances. Throughout the paper the approximation schemes are discussed and tested. (authors)

  8. Arrhenius temperature dependence of in vitro tissue plasminogen activator thrombolysis

    International Nuclear Information System (INIS)

    Shaw, George J; Dhamija, Ashima; Bavani, Nazli; Wagner, Kenneth R; Holland, Christy K

    2007-01-01

    Stroke is a devastating disease and a leading cause of death and disability. Currently, the only FDA approved therapy for acute ischemic stroke is the intravenous administration of the thrombolytic medication, recombinant tissue plasminogen activator (tPA). However, this treatment has many contraindications and can have dangerous side effects such as intra-cerebral hemorrhage. These treatment limitations have led to much interest in potential adjunctive therapies, such as therapeutic hypothermia (T ≤ 35 deg. C) and ultrasound enhanced thrombolysis. Such interest may lead to combining these therapies with tPA to treat stroke, however little is known about the effects of temperature on the thrombolytic efficacy of tPA. In this work, we measure the temperature dependence of the fractional clot mass loss Δm(T) resulting from tPA exposure in an in vitro human clot model. We find that the temperature dependence is well described by an Arrhenius temperature dependence with an effective activation energy E eff of 42.0 ± 0.9 kJ mole -1 . E eff approximates the activation energy of the plasminogen-to-plasmin reaction of 48.9 kJ mole -1 . A model to explain this temperature dependence is proposed. These results will be useful in predicting the effects of temperature in future lytic therapies

  9. Temperature dependence of postmortem MR quantification for soft tissue discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Zech, Wolf-Dieter; Schwendener, Nicole; Jackowski, Christian [University of Bern, From the Institute of Forensic Medicine, Bern (Switzerland); Persson, Anders; Warntjes, Marcel J. [University of Linkoeping, The Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden)

    2015-08-15

    To investigate and correct the temperature dependence of postmortem MR quantification used for soft tissue characterization and differentiation in thoraco-abdominal organs. Thirty-five postmortem short axis cardiac 3-T MR examinations were quantified using a quantification sequence. Liver, spleen, left ventricular myocardium, pectoralis muscle and subcutaneous fat were analysed in cardiac short axis images to obtain mean T1, T2 and PD tissue values. The core body temperature was measured using a rectally inserted thermometer. The tissue-specific quantitative values were related to the body core temperature. Equations to correct for temperature differences were generated. In a 3D plot comprising the combined data of T1, T2 and PD, different organs/tissues could be well differentiated from each other. The quantitative values were influenced by the temperature. T1 in particular exhibited strong temperature dependence. The correction of quantitative values to a temperature of 37 C resulted in better tissue discrimination. Postmortem MR quantification is feasible for soft tissue discrimination and characterization of thoraco-abdominal organs. This provides a base for computer-aided diagnosis and detection of tissue lesions. The temperature dependence of the T1 values challenges postmortem MR quantification. Equations to correct for the temperature dependence are provided. (orig.)

  10. Quasi-pions with temperature dependent dispersion relation

    International Nuclear Information System (INIS)

    Gorenstein, M.I.

    1995-01-01

    We construct the procedure to calculate thermodynamical functions for a system of quasi-particles with temperature dependent dispersion relation. Two models for the hot quasi-pion system are considered to illustrate the importance of thermodynamical self consistency requirements. 8 refs., 9 figs

  11. Temperature dependence of the μ+ hyperfine field in ferromagnets

    International Nuclear Information System (INIS)

    Nagamine, K.; Nirhida, N.; Hayano, R.S.; Yamazaki, T.; Brewes, J.H.; Fleming, D.G.

    1977-01-01

    The temperature dependences of the μ + hyperfine fields in Ni and in Fe were found to deviate from that of the saturation magnetization in opposite senses. Difference in the screening mechanism of conduction electrons around the μ + is considered, among several possible explanations. (Auth.)

  12. Arrhenius temperature dependence of in vitro tissue plasminogen activator thrombolysis

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, George J [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Dhamija, Ashima [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Bavani, Nazli [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Wagner, Kenneth R [Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Holland, Christy K [Department of Biomedical Engineering, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States)

    2007-06-07

    Stroke is a devastating disease and a leading cause of death and disability. Currently, the only FDA approved therapy for acute ischemic stroke is the intravenous administration of the thrombolytic medication, recombinant tissue plasminogen activator (tPA). However, this treatment has many contraindications and can have dangerous side effects such as intra-cerebral hemorrhage. These treatment limitations have led to much interest in potential adjunctive therapies, such as therapeutic hypothermia (T {<=} 35 deg. C) and ultrasound enhanced thrombolysis. Such interest may lead to combining these therapies with tPA to treat stroke, however little is known about the effects of temperature on the thrombolytic efficacy of tPA. In this work, we measure the temperature dependence of the fractional clot mass loss {delta}m(T) resulting from tPA exposure in an in vitro human clot model. We find that the temperature dependence is well described by an Arrhenius temperature dependence with an effective activation energy E{sub eff} of 42.0 {+-} 0.9 kJ mole{sup -1}. E{sub eff} approximates the activation energy of the plasminogen-to-plasmin reaction of 48.9 kJ mole{sup -1}. A model to explain this temperature dependence is proposed. These results will be useful in predicting the effects of temperature in future lytic therapies.

  13. Temperature dependence of the resonance frequency of thermogravimetric devices

    NARCIS (Netherlands)

    Iervolino, E.; Riccio, M.; Van Herwaarden, A.W.; Irace, A.; Breglio, G.; Van der Vlist, W.; Sarro, P.M.

    2010-01-01

    This paper investigates the temperature dependence of the resonance frequency of thermogravimetric (TG) devices for tip heating over the temperature range of View the MathML source 25–600?C. The resonance frequency of a fabricated TG device shows to be temperature independent for tip heating up to

  14. Temperature Dependence of Lattice Dynamics of Lithium 7

    DEFF Research Database (Denmark)

    Beg, M. M.; Nielsen, Mourits

    1976-01-01

    10% smaller than those at 100 K. Temperature dependences of selected phonons have been studied from 110 K to near the melting point. The energy shifts and phonon linewidths have been evaluated at 293, 383, and 424 K by comparing the widths and energies to those measured at 110 K. The lattice...

  15. Anomalous temperature dependence of excitation transfer between quantum dots

    Czech Academy of Sciences Publication Activity Database

    Král, Karel; Menšík, Miroslav

    2015-01-01

    Roč. 7, č. 4 (2015), 325-330 ISSN 2164-6627 R&D Projects: GA MŠk(CZ) LD14011; GA MŠk LH12236; GA MŠk LH12186 Institutional support: RVO:68378271 ; RVO:61389013 Keywords : excitation transfer * quantum dots * temperature dependence * electron-phonon interaction Subject RIV: BM - Solid Matter Physics ; Magnetism

  16. Temperature dependence of critical resolved shear stress for cubic metals

    International Nuclear Information System (INIS)

    Rashid, H.; Fazal-e-Aleem; Ali, M.

    1996-01-01

    The experimental measurements for critical resolved shear stress of various BCC and FCC metals have been explained by using Radiation Model. The temperature dependence of CRSS for different cubic metals is found to the first approximation, to upon the type of the crystal. A good agreement between experimental observations and predictions of the Radiation Model is found. (author)

  17. Temperature dependence of collapse of quantized hall resistance

    International Nuclear Information System (INIS)

    Tanaka, Hiroyasu; Kawashima, Hironori; Iizuka, Hisamitsu; Fukuda, Hideaki; Kawaji, Shinji

    2006-01-01

    Similarity is observed in the deviation of Hall resistance from the quantized value with the increase in the source-drain current I SD in our butterfly-type Hall bars and in the Hall bars used by Jeanneret et al., while changes in the diagonal resistivity ρ xx with I SD are significantly different between these Hall bars. The temperature dependence of the critical Hall electric field F cr (T) for the collapse of R H (4) measured in these Hall bars is approximated using F cr (T) = F cr (0)(1 - (T/T cr ) 2 ). Here, the critical Hall electric field at zero temperature depends on the magnetic field B as F cr (0) ∝ B 3/2 . Theoretical considerations are given on F cr (T) on the basis of a temperature-dependent mobility edge model and a schema of temperature-dependent inter-Landau level tunneling probability arising from the Fermi distribution function. The former does not fit in with the I SD dependence of activation energy in ρ xx . (author)

  18. Temperature dependence of electron concentration in cadmium arsenide

    NARCIS (Netherlands)

    Gelten, M.J.; Blom, F.A.P.

    1979-01-01

    From measurements of the temperature dependence of the electron concentration in Cd 3 As 2 , we found values for the conduction-band parameters that are in good agreement with those recently reported by Aubin, Caron, and Jay-Gerin. However, in contrast with these authors we found no small overlap,

  19. Crossing regimes of temperature dependence in animal movement.

    Science.gov (United States)

    Gibert, Jean P; Chelini, Marie-Claire; Rosenthal, Malcolm F; DeLong, John P

    2016-05-01

    A pressing challenge in ecology is to understand the effects of changing global temperatures on food web structure and dynamics. The stability of these complex ecological networks largely depends on how predator-prey interactions may respond to temperature changes. Because predators and prey rely on their velocities to catch food or avoid being eaten, understanding how temperatures may affect animal movement is central to this quest. Despite our efforts, we still lack a mechanistic understanding of how the effect of temperature on metabolic processes scales up to animal movement and beyond. Here, we merge a biomechanical approach, the Metabolic Theory of Ecology and empirical data to show that animal movement displays multiple regimes of temperature dependence. We also show that crossing these regimes has important consequences for population dynamics and stability, which depend on the parameters controlling predator-prey interactions. We argue that this dependence upon interaction parameters may help explain why experimental work on the temperature dependence of interaction strengths has so far yielded conflicting results. More importantly, these changes in the temperature dependence of animal movement can have consequences that go well beyond ecological interactions and affect, for example, animal communication, mating, sensory detection, and any behavioral modality dependent on the movement of limbs. Finally, by not taking into account the changes in temperature dependence reported here we might not be able to properly forecast the impact of global warming on ecological processes and propose appropriate mitigation action when needed. © 2016 John Wiley & Sons Ltd.

  20. Temperature dependence of dose rate laser simulation adequacy

    International Nuclear Information System (INIS)

    Skorobogatov, P.K.; Nikiforov, A.Y.; Demidov, A.A.

    1999-01-01

    2-D numerical modeling was carried out to analyze the temperature dependence of dose rate laser simulation adequacy in application to p-n junction ionising current. Experimental validation was performed using test structure in the temperature range of 0 to 100 deg.C. (authors)

  1. Temperature dependence of postmortem MR quantification for soft tissue discrimination

    International Nuclear Information System (INIS)

    Zech, Wolf-Dieter; Schwendener, Nicole; Jackowski, Christian; Persson, Anders; Warntjes, Marcel J.

    2015-01-01

    To investigate and correct the temperature dependence of postmortem MR quantification used for soft tissue characterization and differentiation in thoraco-abdominal organs. Thirty-five postmortem short axis cardiac 3-T MR examinations were quantified using a quantification sequence. Liver, spleen, left ventricular myocardium, pectoralis muscle and subcutaneous fat were analysed in cardiac short axis images to obtain mean T1, T2 and PD tissue values. The core body temperature was measured using a rectally inserted thermometer. The tissue-specific quantitative values were related to the body core temperature. Equations to correct for temperature differences were generated. In a 3D plot comprising the combined data of T1, T2 and PD, different organs/tissues could be well differentiated from each other. The quantitative values were influenced by the temperature. T1 in particular exhibited strong temperature dependence. The correction of quantitative values to a temperature of 37 C resulted in better tissue discrimination. Postmortem MR quantification is feasible for soft tissue discrimination and characterization of thoraco-abdominal organs. This provides a base for computer-aided diagnosis and detection of tissue lesions. The temperature dependence of the T1 values challenges postmortem MR quantification. Equations to correct for the temperature dependence are provided. (orig.)

  2. Temperature Dependence Viscosity and Density of Different Biodiesel Blends

    Directory of Open Access Journals (Sweden)

    Vojtěch Kumbár

    2015-01-01

    Full Text Available The main goal of this paper is to assess the effect of rapeseed oil methyl ester (RME concentration in diesel fuel on its viscosity and density behaviour. The density and dynamic viscosity were observed at various mixing ratios of RME and diesel fuel. All measurements were performed at constant temperature of 40 °C. Increasing ratio of RME in diesel fuel was reflected in increased density value and dynamic viscosity of the blend. In case of pure RME, pure diesel fuel, and a blend of both (B30, temperature dependence of dynamic viscosity and density was examined. Temperature range in the experiment was −10 °C to 80 °C. Considerable temperature dependence of dynamic viscosity and density was found and demonstrated for all three samples. This finding is in accordance with theoretical assumptions and reference data. Mathematical models were developed and tested. Temperature dependence of dynamic viscosity was modeled using a polynomial 3rd polynomial degree. Correlation coefficients R −0.796, −0.948, and −0.974 between measured and calculated values were found. Temperature dependence of density was modeled using a 2nd polynomial degree. Correlation coefficients R −0.994, −0.979, and −0.976 between measured and calculated values were acquired. The proposed models can be used for flow behaviour prediction of RME, diesel fuel, and their blends.

  3. Sex differences in depression and anxiety disorders: potential biological determinants.

    Science.gov (United States)

    Altemus, Margaret

    2006-11-01

    The phenomenon of higher rates of affective disorders in women illustrates many of the difficulties as well as promises of translating preclinical models to human disorders. Abnormalities in the regulation of the hypothalamic-pituitary adrenal axis and the sympathoadrenomedullary system have been identified in depression and anxiety disorders, and these disorders are clearly precipitated and exacerbated by stress. Despite the striking sex difference in the prevalence of depression and anxiety disorders, attempts to identify corresponding sex differences in stress response reactivity in animal models have met with limited success. Processes which may contribute to increased rates of affective disorders in women are greater fluxes in reproductive hormones across the life span, and increased sensitivity to catecholamine augmentation of emotional memory consolidation.

  4. COMPLEMENTARY SEX DETERMINATION IN HYMENOPTERAN PARASITOIDS AND ITS IMPLICATIONS FOR BIOLOGICAL CONTROL

    Institute of Scientific and Technical Information of China (English)

    WUZhishan; KeithR.Hopper; PaulJ.Ode; RogerW.Fuester; CHENJia-hua; GeorgeE.Heimpel

    2003-01-01

    In haplodiploid Hymenoptera, unfertilized eggs produce haploid males while fertilized eggs lead to diploid females under most circumstances. Diploid males can also be produced from fertilization under a system of sex determination known as complementary sex determination (CSD). Under single-locus CSD, sex is determined by multiple alleles at a single sex locus. Individuals heterozygous at the sex locus are female while hemizygous and homozygous individuals develop as haploid and diploid males, respectively. In multiple-locus CSD, two or more loci, each with two or more alleles, determine sex. Diploid individuals are female if one or more sex loci are het-erozygous, while a diploid is male only if homozygous at all sex loci. Diploid males are known to occur in 43 hym-enopteran species and single-locus CSD has been demonstrated in 22 of these species. Diploid males are either developmentally inviable or sterile, so their production constitutes a genetic load. Because diploid male production is more likely under inbreeding, CSD is a form of inbreeding depression. It is crucial to preserve the diversity of sex alleles and reduce the loss of genetic variation in biological control. In the parasitoid species with single-locus CSD, certain precautionary procedures can prevent negative effects of single-locus CSD on biological control.

  5. Abortion and sex determination: conflicting messages in information materials in a District of Rajasthan, India.

    Science.gov (United States)

    Nidadavolu, Vijaya; Bracken, Hillary

    2006-05-01

    Public information campaigns are an integral component of reproductive health programmes, including on abortion. In India, where sex selective abortion is increasing, public information is being disseminated on the illegality of sex determination. This paper presents findings from a study undertaken in 2003 in one district in Rajasthan to analyse the content of information materials on abortion and sex determination and people's perceptions of them. Most of the informational material about abortion was produced by one abortion service provider, but none by the public or private sector. The public sector had produced materials on the illegality of sex determination, some of which failed to distinguish between sex selection and other reasons for abortion. In the absence of knowledge of the legal status of abortion, the negative messages and strong language of these materials may have contributed to the perception that abortion is illegal in India. Future materials should address abortion and sex determination, including the legal status of abortion, availability of providers and social norms that shape decision-making. Married and unmarried women should be addressed and the participation of family members acknowledged, while supporting independent decisions by women. Sex determination should also be addressed, and the conditions under which a woman can and cannot seek an abortion clarified, using media and materials accessible to low-literate audiences. Based on what we learned in this research, a pictorial booklet and educator's manual were produced, covering both abortion and sex determination, and are being distributed in India.

  6. Prevalence and determinants of online-sex use in the German population.

    Directory of Open Access Journals (Sweden)

    Manfred E Beutel

    Full Text Available The unlimited access to sexual features in the World Wide Web has raised concerns about excessive and problematic online-sex use. However, little is known about antecedents of internet-sex use of different intensity. Based on a representative German sample of 2,522 participants between the ages of 14 and 97 years, the aims of the present study were (1 to determine the prevalence rates of online-sex users with the short version (ISSTGSV of the Internet Sex Screening Test and (2 to associate online-sex use with anxious vs. avoidant partner attachment patterns and "Big Five" personality traits as potential antecedents.The ISST is a brief, one-dimensional and reliable measure of online-sex activities (rtt = .69. Overall, 14.7% of respondents reported occasional and 4.2% intensive online-sex use. In multivariate analysis, online-sex use was significantly positively associated with male sex, younger age, unemployment and an anxious partner attachment pattern and negatively with conscientiousness and agreeableness.Arousal and satisfaction by virtual enactment of sexual phantasies may be attractive for anxiously attached persons who find it difficult to commit to a real life relationship due to fear of rejection or low self-esteem. More knowledge about the individual antecedents of intensive online-sex use may also be helpful for the development of consultation and treatment strategies for excessive and addictive online-sex use.

  7. Prevalence and determinants of online-sex use in the German population.

    Science.gov (United States)

    Beutel, Manfred E; Giralt, Sebastian; Wölfling, Klaus; Stöbel-Richter, Yve; Subic-Wrana, Claudia; Reiner, Iris; Tibubos, Ana Nanette; Brähler, Elmar

    2017-01-01

    The unlimited access to sexual features in the World Wide Web has raised concerns about excessive and problematic online-sex use. However, little is known about antecedents of internet-sex use of different intensity. Based on a representative German sample of 2,522 participants between the ages of 14 and 97 years, the aims of the present study were (1) to determine the prevalence rates of online-sex users with the short version (ISSTGSV) of the Internet Sex Screening Test and (2) to associate online-sex use with anxious vs. avoidant partner attachment patterns and "Big Five" personality traits as potential antecedents. The ISST is a brief, one-dimensional and reliable measure of online-sex activities (rtt = .69). Overall, 14.7% of respondents reported occasional and 4.2% intensive online-sex use. In multivariate analysis, online-sex use was significantly positively associated with male sex, younger age, unemployment and an anxious partner attachment pattern and negatively with conscientiousness and agreeableness. Arousal and satisfaction by virtual enactment of sexual phantasies may be attractive for anxiously attached persons who find it difficult to commit to a real life relationship due to fear of rejection or low self-esteem. More knowledge about the individual antecedents of intensive online-sex use may also be helpful for the development of consultation and treatment strategies for excessive and addictive online-sex use.

  8. Validation and use of DNA markers for sex determination in papaya (Carica papaya)

    International Nuclear Information System (INIS)

    Ejaz, M.; Iqbal, M.; Ahmed, I.

    2015-01-01

    Profitable papaya production requires female and hermaphrodite plants in higher number than male plants. This is only possible if sex of plants is determined at an early growth stage. The present study was conducted to validate sex-linked DNA markers using plants from two Pakistani papaya varieties and subsequently utilize them for determination of sex in juvenile papaya plants. One hundred and five plants (including 49 male and 56 female) of two Pakistani Papaya varieties at flowering stage were screened with six DNA markers viz., W-11, T12, SDP, Napf-76Napf-76, PKBT4 and PKBT5. All male plants exhibited amplification of sex-linked alleles with markers T12 and W11, whereas, 96% and 95% of female plants showed the absence of sex-linked allele with these markers, respectively. Markers SDP, PKBT5 and Napf-76 showed the presence of sex-linked alleles in 98%, 96% and 93% of male plants, respectively, whereas the same markers showed the absence of sex-linked alleles in 100%, 96% and 94% of female plants. One marker, PKBT4 could not produce expected PCR amplification reported previously. The five DNA markers were further used to screen 171 papaya seedlings. These markers clearly differentiated male and female sex types in the studied papaya plants. Results of our study are likely to facilitate Pakistani papaya breeders and growers to incorporate DNA based screening at juvenile stage to determine sex at early stage and to ensure profitable papaya production. (author)

  9. A heritable component in sex ratio and caste determination in a Cardiocondyla ant

    Directory of Open Access Journals (Sweden)

    Heinze Jürgen

    2009-10-01

    Full Text Available Abstract Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias" - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids. Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals. Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals even when uniformly nursed by workers from another colony. Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.

  10. A heritable component in sex ratio and caste determination in a Cardiocondyla ant.

    Science.gov (United States)

    Frohschammer, Sabine; Heinze, Jürgen

    2009-10-28

    Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias") - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids.Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals). Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals) even when uniformly nursed by workers from another colony.Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.

  11. Chromosome Banding in Amphibia. XXXVI. Multimorphic Sex Chromosomes and an Enigmatic Sex Determination in Eleutherodactylus johnstonei (Anura, Eleutherodactylidae).

    Science.gov (United States)

    Schmid, Michael; Steinlein, Claus

    2018-01-01

    A detailed cytogenetic study on the leaf litter frog Eleutherodactylus johnstonei from 14 different Caribbean islands and the mainlands of Venezuela and Guyana revealed the existence of multimorphic XY♂/XX♀ sex chromosomes 14. Their male sex determination and development depends either on the presence of 2 telocentric chromosomes 14 (XtYt), or on 1 submetacentric chromosome 14 (Xsm) plus 1 telocentric chromosome 14 (Yt), or on the presence of 2 submetacentric chromosomes 14 (XsmYsm). The female sex determination and development requires either the presence of 2 telocentric chromosomes 14 (XtXt) or 2 submetacentric chromosomes 14 (XsmXsm). In all individuals analyzed, the sex chromosomes 14 carry a prominent nucleolus organizer region in their long arms. An explanation is given for the origin of the (XtYt)♂, (XsmYt)♂, (XsmYsm)♂, (XtXt)♀, and (XsmXsm)♀ in the different populations of E. johnstonei. Furthermore, the present study gives detailed data on the chromosome banding patterns, in situ hybridization experiments, and the genome size of E. johnstonei. © 2018 S. Karger AG, Basel.

  12. Convergent evolution of chromosomal sex-determining regions in the animal and fungal kingdoms.

    Directory of Open Access Journals (Sweden)

    James A Fraser

    2004-12-01

    Full Text Available Sexual identity is governed by sex chromosomes in plants and animals, and by mating type (MAT loci in fungi. Comparative analysis of the MAT locus from a species cluster of the human fungal pathogen Cryptococcus revealed sequential evolutionary events that fashioned this large, highly unusual region. We hypothesize that MAT evolved via four main steps, beginning with acquisition of genes into two unlinked sex-determining regions, forming independent gene clusters that then fused via chromosomal translocation. A transitional tripolar intermediate state then converted to a bipolar system via gene conversion or recombination between the linked and unlinked sex-determining regions. MAT was subsequently subjected to intra- and interallelic gene conversion and inversions that suppress recombination. These events resemble those that shaped mammalian sex chromosomes, illustrating convergent evolution in sex-determining structures in the animal and fungal kingdoms.

  13. Ocean acidification but not warming alters sex determination in the Sydney rock oyster, Saccostrea glomerata.

    Science.gov (United States)

    Parker, Laura M; O'Connor, Wayne A; Byrne, Maria; Dove, Michael; Coleman, Ross A; Pörtner, Hans-O; Scanes, Elliot; Virtue, Patti; Gibbs, Mitchell; Ross, Pauline M

    2018-02-14

    Whether sex determination of marine organisms can be altered by ocean acidification and warming during this century remains a significant, unanswered question. Here, we show that exposure of the protandric hermaphrodite oyster, Saccostrea glomerata to ocean acidification, but not warming, alters sex determination resulting in changes in sex ratios. After just one reproductive cycle there were 16% more females than males. The rate of gametogenesis, gonad area, fecundity, shell length, extracellular pH and survival decreased in response to ocean acidification. Warming as a sole stressor slightly increased the rate of gametogenesis, gonad area and fecundity, but this increase was masked by the impact of ocean acidification at a level predicted for this century. Alterations to sex determination, sex ratios and reproductive capacity will have flow on effects to reduce larval supply and population size of oysters and potentially other marine organisms. © 2018 The Author(s).

  14. Physical Attractiveness, Age, and Sex as Determinants of Reactions to Resumes.

    Science.gov (United States)

    Quereshi, M. Y.; Kay, Janet P.

    1986-01-01

    Physical attractiveness, age, and sex were manipulated to determine their effect on the evaluation of 54 hypothetical applicants' resumes for three different jobs by 60 Master's in Business Administration students. Physical attractiveness favorably influenced the suitability ratings for all jobs; raters' sex and age were not significant but…

  15. Genetic sex determination in Astatotilapia calliptera, a prototype species for the Lake Malawi cichlid radiation

    Science.gov (United States)

    Peterson, Erin N.; Cline, Maggie E.; Moore, Emily C.; Roberts, Natalie B.; Roberts, Reade B.

    2017-06-01

    East African cichlids display extensive variation in sex determination systems. The species Astatotilapia calliptera is one of the few cichlids that reside both in Lake Malawi and in surrounding waterways. A. calliptera is of interest in evolutionary studies as a putative immediate outgroup species for the Lake Malawi species flock and possibly as a prototype ancestor-like species for the radiation. Here, we use linkage mapping to test association of sex in A. calliptera with loci that have been previously associated with genetic sex determination in East African cichlid species. We identify a male heterogametic XY system segregating at linkage group (LG) 7 in an A. calliptera line that originated from Lake Malawi, at a locus previously shown to act as an XY sex determination system in multiple species of Lake Malawi cichlids. Significant association of genetic markers and sex produce a broad genetic interval of approximately 26 megabases (Mb) using the Nile tilapia genome to orient markers; however, we note that the marker with the strongest association with sex is near a gene that acts as a master sex determiner in other fish species. We demonstrate that alleles of the marker are perfectly associated with sex in Metriaclima mbenjii, a species from the rock-dwelling clade of Lake Malawi. While we do not rule out the possibility of other sex determination loci in A. calliptera, this study provides a foundation for fine mapping of the cichlid sex determination gene on LG7 and evolutionary context regarding the origin and persistence of the LG7 XY across diverse, rapidly evolving lineages.

  16. Sexy splicing: regulatory interplays governing sex determination from Drosophila to mammals.

    Science.gov (United States)

    Lalli, Enzo; Ohe, Kenji; Latorre, Elisa; Bianchi, Marco E; Sassone-Corsi, Paolo

    2003-02-01

    A remarkable array of strategies is used to produce sexual differentiation in different species. Complex gene hierarchies govern sex determination pathways, as exemplified by the classic D. melanogaster paradigm, where an interplay of transcriptional, splicing and translational mechanisms operate. Molecular studies support the hypothesis that genetic sex determination pathways evolved in reverse order, from downstream to upstream genes, in the cascade. The recent identification of a role for the key regulatory factors SRY and WT1(+KTS) in pre-mRNA splicing indicates that important steps in the mammalian sex determination process are likely to operate at the post-transcriptional level.

  17. On the Temperature Dependence of the UNIQUAC/UNIFAC Models

    DEFF Research Database (Denmark)

    Skjold-Jørgensen, Steen; Rasmussen, Peter; Fredenslund, Aage

    1980-01-01

    of the simultaneous correlation. The temperature dependent parameters have, however, little physical meaning and very odd results are frequently obtained when the interaction parameters obtained from excess enthalpy information alone are used for the prediction of vapor-liquid equilibria. The UNIQUAC/UNIFAC models...... parameters based on excess enthalpy data, and the prediction of excess enthalpy information from only one isothermal set of vapor-liquid equilibrium data is qualitatively acceptable. A parameter table for the modified UNIFAC model is given for the five main groups: CH2, C = C, ACH, ACCH2 and CH2O.......Local composition models for the description of the properties of liquid mixtures do not in general give an accurate representation of excess Gibbs energy and excess enthalpy simultaneously. The introduction of temperature dependent interaction parameters leads to considerable improvements...

  18. Temperature dependence of high field electromechanical coupling in ferroelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, P M; Cain, M G; Stewart, M, E-mail: paul.weaver@npl.co.u [National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW (United Kingdom)

    2010-04-28

    A study of the temperature dependence of the electromechanical response of ferroelectric lead zirconate titanate (PZT) ceramics at high electric fields (up to 1.3 kV mm{sup -1}) is reported. Simultaneous measurements were performed of strain, electric field and polarization to form a complete response map from room temperature up to 200 {sup 0}C. An electrostrictive model is shown to provide an accurate description of the electromechanical response to high levels of induced polarization and electric field. This provides a method for decoupling strain contributions from thermal expansion and polarization changes. Direct measurements of electrostriction and thermal expansion, above and below the Curie temperature, are reported. Electrostriction coefficients are shown to be temperature dependent in these ceramic materials, with different values above and below the Curie temperature.

  19. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    Science.gov (United States)

    Nicovich, J. M.; Wine, P. H.

    1988-01-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  20. Temperature dependence of magnetoresistance in lanthanum manganite ceramics

    International Nuclear Information System (INIS)

    Gubkin, M.K.; Zalesskii, A.V.; Perekalina, T.M.

    1996-01-01

    Magnetoresistivity in the La0.9Na0.1Mn0.9(V,Co)0.1O3 and LaMnO3+δ ceramics was studied. The temperature dependence of magnetoresistance in these specimens was found to differ qualitatively from that in the La0.9Na0.1MnO3 single crystal (the magnetoresistance value remains rather high throughout the measurement range below the Curie temperature), with the maximum values being about the same (20-40% in the field of 20 kOe). Previously published data on magnetization, high frequency magnetic susceptibility, and local fields at the 139La nuclei of the specimens with similar properties attest to their magnetic inhomogeneity. The computation of the conductivity of the nonuniformly ordered lanthanum manganite was performed according to the mean field theory. The calculation results allow one to interpret qualitatively various types of experimental temperature dependences of magnetoresistance

  1. Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins

    DEFF Research Database (Denmark)

    Fago, A.; Wells, R.M.G.; Weber, Roy E.

    1997-01-01

    The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff plot...... (logP(50) vs 1/T) of D. mawsoni hemoglobin indicates that the enthalpy of oxygenation (slope of the plot) is temperature dependent and that at high temperatures oxygen-binding becomes less exothermic. Nearly linear relationships were found in the hemoglobins of the other two species. The data were...... oxygen binding. The degree of the temperature dependence of the heat of oxygenation observed in these hemoglobins seems to reflect the differences in their allosteric effects rather than a specific molecular adaptation to low temperatures. Moreover, this study indicates that the disagreement between...

  2. Solubility Temperature Dependence Predicted from 2D Structure

    Directory of Open Access Journals (Sweden)

    Alex Avdeef

    2015-12-01

    Full Text Available The objective of the study was to find a computational procedure to normalize solubility data determined at various temperatures (e.g., 10 – 50 oC to values at a “reference” temperature (e.g., 25 °C. A simple procedure was devised to predict enthalpies of solution, ΔHsol, from which the temperature dependence of intrinsic (uncharged form solubility, log S0, could be calculated. As dependent variables, values of ΔHsol at 25 °C were subjected to multiple linear regression (MLR analysis, using melting points (mp and Abraham solvation descriptors. Also, the enthalpy data were subjected to random forest regression (RFR and recursive partition tree (RPT analyses. A total of 626 molecules were examined, drawing on 2040 published solubility values measured at various temperatures, along with 77 direct calori    metric measurements. The three different prediction methods (RFR, RPT, MLR all indicated that the estimated standard deviations in the enthalpy data are 11-15 kJ mol-1, which is concordant with the 10 kJ mol-1 propagation error estimated from solubility measurements (assuming 0.05 log S errors, and consistent with the 7 kJ mol-1 average reproducibility in enthalpy values from interlaboratory replicates. According to the MLR model, higher values of mp, H‑bond acidity, polarizability/dipolarity, and dispersion forces relate to more positive (endothermic enthalpy values. However, molecules that are large and have high H-bond basicity are likely to possess negative (exothermic enthalpies of solution. With log S0 values normalized to 25 oC, it was shown that the interlaboratory average standard deviations in solubility measurement are reduced to 0.06 ‑ 0.17 log unit, with higher errors for the least-soluble druglike molecules. Such improvements in data mining are expected to contribute to more reliable in silico prediction models of solubility for use in drug discovery.

  3. Temperature dependence on the time and momentum spectra in germanium

    International Nuclear Information System (INIS)

    Schultz, P.J.; MacKenzie, I.K.

    1982-01-01

    Recent measurements using the slow-#betta# + beam at Brookhaven, have suggested a thermally activated trapping mechanism which inhibited positron diffusion in single-crystal Ge. Supporting evidence has now been obtained from both Doppler broadening and lifetime measurements but, in both cases, the temperature dependence was so weak that it required the use of dual digital stabilization and unusual statistical precision in both types of spectrometry. (Auth.)

  4. Temperature dependence of spreading width of giant dipole resonance

    International Nuclear Information System (INIS)

    Storozhenko, A.N.; Vdovin, A.I.; Ventura, A.; Blokhin, A.I.

    2002-01-01

    The Quasiparticle-Phonon Nuclear Model extended to finite temperature within the framework of Thermo Field Dynamics is applied to calculate a temperature dependence of the spreading width Γ ↓ of a giant dipole resonance. Numerical calculations are made for 120 Sn and 208 Pb nuclei. It is found that Γ ↓ increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones, existing in the literature

  5. Temperature-dependent errors in nuclear lattice simulations

    International Nuclear Information System (INIS)

    Lee, Dean; Thomson, Richard

    2007-01-01

    We study the temperature dependence of discretization errors in nuclear lattice simulations. We find that for systems with strong attractive interactions the predominant error arises from the breaking of Galilean invariance. We propose a local 'well-tempered' lattice action which eliminates much of this error. The well-tempered action can be readily implemented in lattice simulations for nuclear systems as well as cold atomic Fermi systems

  6. Sex Determination in Sea Cucumbers: Holothuria forskali and Stichopus regalis

    Directory of Open Access Journals (Sweden)

    Filipa Pinheiro Santos

    2014-06-01

    Full Text Available Sea cucumber aquaculture is underexploited in temperate regions, and it is inexistent in Portugal. However, there are some species with a large potential for this sector, namely Stichopus regalis and Holothuria forskali, as it their nutritional value. S. regalis is a common sea cucumber that is found in a wide depth range and is currently consumed all over the world, majority in Asia, with a high commercial value. On the other hand, H. forskali is the most plentiful specie of the Portuguese coast. The purpose of this study is to evaluate sex ratio on both species through biopsy method, using biopsy needle to collect a piece of gonad. Holothurian specimens were sampled coastwise in Peniche, Portugal (39° 21′ 32″ N, 9° 22′ 40″ W. A total of 45 H. forskali were collected in the low tide and 48 S. regalis were caught by trawl method. Both species were kept in captivity during 8 months, the rearing conditions are maintained close as possible to the natural habitat, and they were placed in a sand bottom. Mortality was evaluated during conditioning period, and it was verified approximately 19% of mortality in S. regalis, although in H. forskali it was not observed. Sex identification was performed with success only in H. forskali, and sexual ratio found was 1:1. All S. regalis specimens arrived eviscerated to the Aquaculture Laboratory and it was caused by the trawl capture method. For that reason, it was not possible to assess the sexual ratio. The possibility to distinguish holothurian genre is essential to realize sexual behavior, and to ease the understanding of reproductive cycle in attempt to introduce these new species for aquaculture rearing.

  7. A nanoscale temperature-dependent heterogeneous nucleation theory

    International Nuclear Information System (INIS)

    Cao, Y. Y.; Yang, G. W.

    2015-01-01

    Classical nucleation theory relies on the hypothetical equilibrium of the whole nucleation system, and neglects the thermal fluctuations of the surface; this is because the high entropic gains of the (thermodynamically extensive) surface would lead to multiple stable states. In fact, at the nanometer scale, the entropic gains of the surface are high enough to destroy the stability of the thermal equilibrium during nucleation, comparing with the whole system. We developed a temperature-dependent nucleation theory to elucidate the heterogeneous nucleation process, by considering the thermal fluctuations based on classical nucleation theory. It was found that the temperature not only affected the phase transformation, but also influenced the surface energy of the nuclei. With changes in the Gibbs free energy barrier, nucleation behaviors, such as the nucleation rate and the critical radius of the nuclei, showed temperature-dependent characteristics that were different from those predicted by classical nucleation theory. The temperature-dependent surface energy density of a nucleus was deduced based on our theoretical model. The agreement between the theoretical and experimental results suggested that the developed nucleation theory has the potential to contribute to the understanding and design of heterogeneous nucleation at the nanoscale

  8. On the temperature dependence of flammability limits of gases.

    Science.gov (United States)

    Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki

    2011-03-15

    Flammability limits of several combustible gases were measured at temperatures from 5 to 100 °C in a 12-l spherical flask basically following ASHRAE method. The measurements were done for methane, propane, isobutane, ethylene, propylene, dimethyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. As the temperature rises, the lower flammability limits are gradually shifted down and the upper limits are shifted up. Both the limits shift almost linearly to temperature within the range examined. The linear temperature dependence of the lower flammability limits is explained well using a limiting flame temperature concept at the lower concentration limit (LFL)--'White's rule'. The geometric mean of the flammability limits has been found to be relatively constant for many compounds over the temperature range studied (5-100 °C). Based on this fact, the temperature dependence of the upper flammability limit (UFL) can be predicted reasonably using the temperature coefficient calculated for the LFL. However, some compounds such as ethylene and dimethyl ether, in particular, have a more complex temperature dependence. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Temperature dependence of photonic crystals based on thermoresponsive magnetic fluids

    International Nuclear Information System (INIS)

    Pu Shengli; Bai Xuekun; Wang Lunwei

    2011-01-01

    The influence mechanisms of temperature on the band gap properties of the magnetic fluids based photonic crystals are elaborated. A method has been developed to obtain the temperature-dependent structure information (A sol /A) from the existing experimental data and then two critical parameters, i.e. the structure ratio (d/a) and the refractive index contrast (Δn) of the magnetic fluids photonic crystals are deduced for band diagram calculations. The temperature-dependent band gaps are gained for z-even and z-odd modes. Band diagram calculations display that the mid frequencies and positions of the existing forbidden bands are not very sensitive to the temperature, while the number of the forbidden bands at certain strengths of magnetic field may change with the temperature variation. The results presented in this work give a guideline for designing the potential photonic devices based on the temperature characteristics of the magnetic fluids based photonic crystals and are helpful for improving their quality. - Highlights: → Mechanisms of temperature dependence of magnetic fluids based photonic crystals are elaborated. → Properties of existing forbidden bands have relatively fine temperature stability. → Disappearance of existing forbidden band is found for some magnetic fields. → Emergence of new forbidden band with temperature is found for some magnetic fields.

  10. Temperature dependence of the elastocaloric effect in natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Zhongjian, E-mail: zhongjian.xie521@gmail.com; Sebald, Gael; Guyomar, Daniel

    2017-07-12

    The temperature dependence of the elastocaloric (eC) effect in natural rubber (NR) has been studied. This material exhibits a large eC effect over a broad temperature range from 0 °C to 49 °C. The maximum adiabatic temperature change (ΔT) occurred at 10 °C and the behavior could be predicted by the temperature dependence of the strain-induced crystallization (SIC) and the temperature-induced crystallization (TIC). The eC performance of NR was then compared with that of shape memory alloys (SMAs). This study contributes to the SIC research of NR and also broadens the application of elastomers. - Highlights: • A large elastocaloric effect over a broad temperature range was found in natural rubber (NR). • The caloric performance of NR was compared with that of shape memory alloys. • The temperature dependence of the elastocaloric effect in NR can be prediced by the theory of strain-induced crystallization.

  11. Sex determination in gibbons of genus Nomascus using non-invasive method

    Directory of Open Access Journals (Sweden)

    Petra Bolechová

    2016-01-01

    Full Text Available Gibbons of the genus Nomascus have a strong sexual dimorphism and dichromatism. As they mature, both sexes develop sex-specific pelage colour. In combination with physical similarities in the genitalia with both sexes, there are problems with determining the sex of young individuals compared to other genus of gibbons. This is a pilot study applying a multiplex polymerase chain reactions based on a non-invasive method for sex determination of gibbons. The study was conducted on 22 faecal samples from gibbons of the genus Nomascus. The animals were monitored by staff so that the samples were identified correctly and each sample was collected immediately after the defecation. Results confirmed the sex in all adult and juvenile animals with known sex; and 2 females and 5 males in juveniles were determined with unknown sex. The results of direct examination completely corresponded with the PCR results. The PCR reaction with template DNA isolated from faecal material required BSA usage, however, we observed the occurrence of nonspecific fragments. This did not affect the reliability of our results and we confirmed the usability of this method for this genus.

  12. Sex determination of a Tunisian population by CT scan analysis of the skull.

    Science.gov (United States)

    Zaafrane, Malek; Ben Khelil, Mehdi; Naccache, Ines; Ezzedine, Ekbel; Savall, Frédéric; Telmon, Norbert; Mnif, Najla; Hamdoun, Moncef

    2018-05-01

    It is widely accepted that the estimation of biological attributes in the human skeleton is more accurate when population-specific standards are applied. With the shortage of such data for contemporary North African populations, it is duly required to establish population-specific standards. We present here the first craniometric standards for sex determination of a contemporary Tunisian population. The aim of this study was to analyze the correlation between sex and metric parameters of the skull in this population using CT scan analysis and to generate proper reliable standards for sex determination of a complete or fragmented skull. The study sample comprised cranial multislice computed tomography scans of 510 individuals equally distributed by sex. ASIR TM software in a General Electric TM workstation was used to position 37 landmarks along the volume-rendered images and the multiplanar slices, defining 27 inter-landmark distances. Frontal and parietal bone thickness was also measured for each case. The data were analyzed using basic descriptive statistics and logistic regression with cross-validation of classification results. All of the measurements were sexually dimorphic with male values being higher than female values. A nine-variable model achieved the maximum classification accuracy of 90% with -2.9% sex bias and a six-variable model yielded 85.9% sexing accuracy with -0.97% sex bias. We conclude that the skull is highly dimorphic and represents a reliable bone for sex determination in contemporary Tunisian individuals.

  13. Absence of complementary sex determination in the parasitoid wasp genus Asobara (Hymenoptera: Braconidae.

    Directory of Open Access Journals (Sweden)

    Wen-Juan Ma

    Full Text Available An attractive way to improve our understanding of sex determination evolution is to study the underlying mechanisms in closely related species and in a phylogenetic perspective. Hymenopterans are well suited owing to the diverse sex determination mechanisms, including different types of Complementary Sex Determination (CSD and maternal control sex determination. We investigated different types of CSD in four species within the braconid wasp genus Asobara that exhibit diverse life-history traits. Nine to thirteen generations of inbreeding were monitored for diploid male production, brood size, offspring sex ratio, and pupal mortality as indicators for CSD. In addition, simulation models were developed to compare these observations to predicted patterns for multilocus CSD with up to ten loci. The inbreeding regime did not result in diploid male production, decreased brood sizes, substantially increased offspring sex ratios nor in increased pupal mortality. The simulations further allowed us to reject CSD with up to ten loci, which is a strong refutation of the multilocus CSD model. We discuss how the absence of CSD can be reconciled with the variation in life-history traits among Asobara species, and the ramifications for the phylogenetic distribution of sex determination mechanisms in the Hymenoptera.

  14. Fgf9 and Wnt4 act as antagonistic signals to regulate mammalian sex determination.

    Directory of Open Access Journals (Sweden)

    Yuna Kim

    2006-06-01

    Full Text Available The genes encoding members of the wingless-related MMTV integration site (WNT and fibroblast growth factor (FGF families coordinate growth, morphogenesis, and differentiation in many fields of cells during development. In the mouse, Fgf9 and Wnt4 are expressed in gonads of both sexes prior to sex determination. Loss of Fgf9 leads to XY sex reversal, whereas loss of Wnt4 results in partial testis development in XX gonads. However, the relationship between these signals and the male sex-determining gene, Sry, was unknown. We show through gain- and loss-of-function experiments that fibroblast growth factor 9 (FGF9 and WNT4 act as opposing signals to regulate sex determination. In the mouse XY gonad, Sry normally initiates a feed-forward loop between Sox9 and Fgf9, which up-regulates Fgf9 and represses Wnt4 to establish the testis pathway. Surprisingly, loss of Wnt4 in XX gonads is sufficient to up-regulate Fgf9 and Sox9 in the absence of Sry. These data suggest that the fate of the gonad is controlled by antagonism between Fgf9 and Wnt4. The role of the male sex-determining switch--Sry in the case of mammals--is to tip the balance between these underlying patterning signals. In principle, sex determination in other vertebrates may operate through any switch that introduces an imbalance between these two signaling pathways.

  15. Manipulation of arthropod sex determination by endosymbionts : Diversity and molecular mechanisms

    NARCIS (Netherlands)

    Ma, W. -J.; Vavre, F.; Beukeboom, L. W.

    2014-01-01

    Arthropods exhibit a large variety of sex determination systems both at the chromosomal and molecular level. Male heterogamety, female heterogamety, and haplodiploidy occur frequently, but partially different genes are involved. Endosymbionts, such as Wolbachia, Cardinium, Rickettsia, and

  16. Three loci on mouse chromosome 5 and 10 modulate sex determination in XX Ods/+ mice.

    Science.gov (United States)

    Poirier, Christophe; Moran, Jennifer L; Kovanci, Ertug; Petit, Deborah C; Beier, David R; Bishop, Colin E

    2007-07-01

    In mouse, XY embryos are committed to the male sex determination pathway after the transient expression of the Y-linked Sry gene in the Sertoli cell lineage between 10.5 and 12.5 dpc. In the C57BL/6J strain, male sex determination program can be modulated by some autosomal genes. The C57BL/6J alleles at these autosomal loci can antagonize male sex determination in combination with specific Sry alleles. In this report, the authors have identified an effect of these C57BL/6J specific alleles in combination with a mutated Sox9 allele, Sox9(Ods). Authors report the mapping of three of these genetic loci on mouse chromosome 5 and 10 in a backcross of the Ods mutation to the C57BL/6J background. Our study confirms the importance of the strain C57BL/6J for the investigation of the genetic mechanisms that control sex determination.

  17. Sex determination based on a thoracic vertebra and ribs evaluation using clinical chest radiography.

    Science.gov (United States)

    Tsubaki, Shun; Morishita, Junji; Usumoto, Yosuke; Sakaguchi, Kyoko; Matsunobu, Yusuke; Kawazoe, Yusuke; Okumura, Miki; Ikeda, Noriaki

    2017-07-01

    Our aim was to investigate whether sex can be determined from a combination of geometric features obtained from the 10th thoracic vertebra, 6th rib, and 7th rib. Six hundred chest radiographs (300 males and 300 females) were randomly selected to include patients of six age groups (20s, 30s, 40s, 50s, 60s, and 70s). Each group included 100 images (50 males and 50 females). A total of 14 features, including 7 lengths, 5 indices for the vertebra, and 2 types of widths for ribs, were utilized and analyzed for sex determination. Dominant features contributing to sex determination were selected by stepwise discriminant analysis after checking the variance inflation factors for multicollinearity. The accuracy of sex determination using a combination of the vertebra and ribs was evaluated from the selected features by the stepwise discriminant analysis. The accuracies in each age group were also evaluated in this study. The accuracy of sex determination based on a combination of features of the vertebra and ribs was 88.8% (533/600). This performance was superior to that of the vertebra or ribs only. Moreover, sex determination of subjects in their 20s demonstrated the highest accuracy (96.0%, 96/100). The features selected in the stepwise discriminant analysis included some features in both the vertebra and ribs. These results indicate the usefulness of combined information obtained from the vertebra and ribs for sex determination. We conclude that a combination of geometric characteristics obtained from the vertebra and ribs could be useful for determining sex. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. A New Component of the Nasonia Sex Determining Cascade Is Maternally Silenced and Regulates Transformer Expression

    Science.gov (United States)

    Bopp, Daniel; Beukeboom, Leo W.; van de Zande, Louis

    2013-01-01

    Although sex determination is a universal process in sexually reproducing organisms, sex determination pathways are among the most highly variable genetic systems found in nature. Nevertheless, general principles can be identified among the diversity, like the central role of transformer (tra) in insects. When a functional TRA protein is produced in early embryogenesis, the female sex determining route is activated, while prevention of TRA production leads to male development. In dipterans, male development is achieved by prevention of female-specific splicing of tra mRNA, either mediated by X-chromosome dose or masculinizing factors. In Hymenoptera, which have haplodiploid sex determination, complementary sex determination and maternal imprinting have been identified to regulate timely TRA production. In the parasitoid Nasonia, zygotic transformer (Nvtra) expression and splicing is regulated by a combination of maternal provision of Nvtra mRNA and silencing of Nvtra expression in unfertilized eggs. It is unclear, however, if this silencing is directly on the tra locus or whether it is mediated through maternal silencing of a trans-acting factor. Here we show that in Nasonia, female sex determination is dependent on zygotic activation of Nvtra expression by an as yet unknown factor. This factor, which we propose to term womanizer (wom), is maternally silenced during oogenesis to ensure male development in unfertilized eggs. This finding implicates the upstream recruitment of a novel gene in the Nasonia sex determining cascade and supports the notion that sex determining cascades can rapidly change by adding new components on top of existing regulators. PMID:23717455

  19. Temperature dependence of the current to sustain a normal hotspot in superconducting microbridges

    International Nuclear Information System (INIS)

    Yamaguchi, Y.; Ishii, C.

    1981-01-01

    A modification of the boundary condition to determine the SN boundary in the hotspot model of superconducting microbridges is proposed and successfully applied to the interpretation of recent measurements of the hotspot-sustaining current by Mizuno and Aomine. It is shown that suppression of the order parameter due to the applied current gives rise to an additional temperature dependence of the hotspot-sustaining current in the extreme vicinity of the transition temperature. (orig.)

  20. Temperature dependence Infrared and Raman studies of III-V/II-VI core-shell nanostructures

    Science.gov (United States)

    Manciu, Felicia S.; McCombe, Bruce D.; Lucey, Derrick

    2005-03-01

    The temperature dependence (8 K InP/ZnS sample. Raman scattering (457.9 nm excitation) features were determined without polarization selection in the backscattering geometry. Interesting T-dependent resonant Raman effect of the surface optical phonon modes has been discovered in InP/ZnSe sample. Reasonable agreement is obtained between the Raman and FIR results, as well as with theoretical calculations.

  1. Environmental sex determination in the branchiopod crustacean Daphnia magna: deep conservation of a Doublesex gene in the sex-determining pathway.

    Directory of Open Access Journals (Sweden)

    Yasuhiko Kato

    2011-03-01

    Full Text Available Sex-determining mechanisms are diverse among animal lineages and can be broadly divided into two major categories: genetic and environmental. In contrast to genetic sex determination (GSD, little is known about the molecular mechanisms underlying environmental sex determination (ESD. The Doublesex (Dsx genes play an important role in controlling sexual dimorphism in genetic sex-determining organisms such as nematodes, insects, and vertebrates. Here we report the identification of two Dsx genes from Daphnia magna, a freshwater branchiopod crustacean that parthenogenetically produces males in response to environmental cues. One of these genes, designated DapmaDsx1, is responsible for the male trait development when expressed during environmental sex determination. The domain organization of DapmaDsx1 was similar to that of Dsx from insects, which are thought to be the sister group of branchiopod crustaceans. Intriguingly, the molecular basis for sexually dimorphic expression of DapmaDsx1 is different from that of insects. Rather than being regulated sex-specifically at the level of pre-mRNA splicing in the coding region, DapmaDsx1 exhibits sexually dimorphic differences in the abundance of its transcripts. During embryogenesis, expression of DapmaDsx1 was increased only in males and its transcripts were primarily detected in male-specific structures. Knock-down of DapmaDsx1 in male embryos resulted in the production of female traits including ovarian maturation, whereas ectopic expression of DapmaDsx1 in female embryos resulted in the development of male-like phenotypes. Expression patterns of another D. magna Dsx gene, DapmaDsx2, were similar to those of DapmaDsx1, but silencing and overexpression of this gene did not induce any clear phenotypic changes. These results establish DapmaDsx1 as a key regulator of the male phenotype. Our findings reveal how ESD is implemented by selective expression of a fundamental genetic component that is

  2. Sex determination using cheiloscopy and mandibular canine index as a tool in forensic dentistry

    Directory of Open Access Journals (Sweden)

    B Bhagyashree

    2018-01-01

    Full Text Available Identification of a person′s individuality and sex determination are important for legal as well as identification purposes. The aim of the present study was to check the reliability of cheiloscopy and mandibular canine index (MCI in the determination of sex in an individual. The aim of this study is to analyze different lip patterns reproduced by the natural dye (vermilion and lysochrome (Sudan Black II dyes and to compare the MCI in males and females for the determination of sex and to check the reliability of cheiloscopy and MCI for the same. Latent lip prints were developed using natural dye (vermilion and lysochrome (Sudan Black II dyes and their patterns categorized according to Tsuchihashi′s classification. MCI were calculated. Analysis of the two was performed. According to discriminant functional analysis, percentage accuracy for cheiloscopy in the determination of sex was found to be 55% while for MCI, the same value was 85%. Natural dye (vermilion was found as an efficient dye compared to lysochrome (Sudan Black II dyes for the development of latent lip prints. Both the dyes showed Type I lip print pattern to be common in males and females. Furthermore, all the parameters in MCI were found to be significant in the determination of sex in an individual. The results of the present study revealed MCI to be more reliable in the determination of sex than cheiloscopy.

  3. Karyotype analysis and sex determination in Australian Brush-turkeys (Alectura lathami.

    Directory of Open Access Journals (Sweden)

    Madison T Ortega

    Full Text Available Sexual differentiation across taxa may be due to genetic sex determination (GSD and/or temperature sex determination (TSD. In many mammals, males are heterogametic (XY; whereas females are homogametic (XX. In most birds, the opposite is the case with females being heterogametic (ZW and males the homogametic sex (ZZ. Many reptile species lack sex chromosomes, and instead, sexual differentiation is influenced by temperature with specific temperatures promoting males or females varying across species possessing this form of sexual differentiation, although TSD has recently been shown to override GSD in Australian central beaded dragons (Pogona vitticeps. There has been speculation that Australian Brush-turkeys (Alectura lathami exhibit TSD alone and/or in combination with GSD. Thus, we sought to determine if this species possesses sex chromosomes. Blood was collected from one sexually mature female and two sexually mature males residing at Sylvan Heights Bird Park (SHBP and shipped for karyotype analysis. Karyotype analysis revealed that contrary to speculation, Australian Brush-turkeys possess the classic avian ZW/ZZ sex chromosomes. It remains a possibility that a biased primary sex ratio of Australian Brush-turkeys might be influenced by maternal condition prior to ovulation that result in her laying predominantly Z- or W-bearing eggs and/or sex-biased mortality due to higher sensitivity of one sex in environmental conditions. A better understanding of how maternal and extrinsic factors might differentially modulate ovulation of Z- or W-bearing eggs and hatching of developing chicks possessing ZW or ZZ sex chromosomes could be essential in conservation strategies used to save endangered members of Megapodiidae.

  4. A NEW HYPOTHESIS ON THE EVOLUTION OF SEX DETERMINATION IN VERTEBRATES - BIG FEMALES ZW, BIG MALES XY

    NARCIS (Netherlands)

    KRAAK, SBM; DELOOZE, EMA

    1993-01-01

    Why are there two chromosomal sex-determining mechanisms in vertebrates; ZW/ZZ, meaning female heterogamety, and XX/XY, meaning male heterogamety? We propose an evolutionary explanation. Transition from environmental sex determination to genetic sex determination can result when an allele that

  5. Mapping of five candidate sex-determining loci in rainbow trout (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Drew Robert E

    2009-01-01

    Full Text Available Abstract Background Rainbow trout have an XX/XY genetic mechanism of sex determination where males are the heterogametic sex. The homology of the sex-determining gene (SDG in medaka to Dmrt1 suggested that SDGs evolve from downstream genes by gene duplication. Orthologous sequences of the major genes of the mammalian sex determination pathway have been reported in the rainbow trout but the map position for the majority of these genes has not been assigned. Results Five loci of four candidate genes (Amh, Dax1, Dmrt1 and Sox6 were tested for linkage to the Y chromosome of rainbow trout. We exclude the role of all these loci as candidates for the primary SDG in this species. Sox6i and Sox6ii, duplicated copies of Sox6, mapped to homeologous linkage groups 10 and 18 respectively. Genotyping fishes of the OSU × Arlee mapping family for Sox6i and Sox6ii alleles indicated that Sox6i locus might be deleted in the Arlee lineage. Conclusion Additional candidate genes should be tested for their linkage to the Y chromosome. Mapping data of duplicated Sox6 loci supports previously suggested homeology between linkage groups 10 and 18. Enrichment of the rainbow trout genomic map with known gene markers allows map comparisons with other salmonids. Mapping of candidate sex-determining loci is important for analyses of potential autosomal modifiers of sex-determination in rainbow trout.

  6. Temperature dependent energy levels of methylammonium lead iodide perovskite

    Science.gov (United States)

    Foley, Benjamin J.; Marlowe, Daniel L.; Sun, Keye; Saidi, Wissam A.; Scudiero, Louis; Gupta, Mool C.; Choi, Joshua J.

    2015-06-01

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.

  7. Temperature dependent energy levels of methylammonium lead iodide perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Foley, Benjamin J.; Marlowe, Daniel L.; Choi, Joshua J., E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Sun, Keye; Gupta, Mool C., E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Saidi, Wissam A. [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States); Scudiero, Louis, E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Chemistry Department and Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164 (United States)

    2015-06-15

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.

  8. Temperature-dependent luminescence dynamics in ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Priller, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany)]. E-mail: heiko.priller@physik.uni-karlsruhe.de; Hauschild, R. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Zeller, J. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Klingshirn, C. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Kalt, H. [Institut fuer Angewandte Physik, Universitaet Karlsruhe and Center for Functional Nanostructures (CFN), Wolfgang-Gaede-Str. 1, D-76131 Karlsruhe (Germany); Kling, R. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Reuss, F. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Kirchner, Ch. [Abteilung Halbleiterphysik, Universitaet Ulm, Albert-Einstein Allee 45, 89081 Ulm (Germany); Waag, A. [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Str. 66, D-38106 Braunschweig (Germany)

    2005-04-15

    We report on an experimental study of the temporal photoluminescence dynamics of high-quality ZnO nanopillars from 10 K to room temperature. We find that defect states play an important role in the time evolution of the photoluminescence signal. At low excitation intensities capture into defects dominates the time dependence of the PL, at higher intensities they are saturated and the intrinsic excitation decay is observed. We separate the intrinsic exciton decay from the fast nonlinear M-band with the method of decay associated spectra and obtain the temperature dependence of the intrinsic exciton decay. High excitation measurements show a reduced exciton-exciton scattering in these thin nanorods.

  9. Temperature Dependence of the Moessbauer Effect on Prussian Blue Nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Pingheng; Xue Desheng; Luo Haiqing; Shi Huigang [Lanzhou University, Key Lab for Magnetism and Magnetic Materials of MOE (China)

    2002-09-15

    Highly ordered Prussian blue nanowires with diameter of about 50 nm and length up to 4 {mu}m have been fabricated by an electrodepositing technology with two-step anodizing anodic aluminum oxide films. The Moessbauer spectra taken between 15 and 300 K indicate that the hyperfine parameters decrease as the temperature increases. The temperature dependence of the quadrupole splitting, the isomer shift and the spectra area are discussed. A decrease of Debye temperature for Prussian blue nanowires was found with respect to that of Prussian blue bulk.

  10. Thermal Aware Floorplanning Incorporating Temperature Dependent Wire Delay Estimation

    DEFF Research Database (Denmark)

    Winther, AndreasThor; Liu, Wei; Nannarelli, Alberto

    2015-01-01

    Temperature has a negative impact on metal resistance and thus wire delay. In state-of-the-art VLSI circuits, large thermal gradients usually exist due to the uneven distribution of heat sources. The difference in wire temperature can lead to performance mismatch because wires of the same length...... can have different delay. Traditional floorplanning algorithms use wirelength to estimate wire performance. In this work, we show that this does not always produce a design with the shortest delay and we propose a floorplanning algorithm taking into account temperature dependent wire delay as one...

  11. Temperature dependence of acceptor-hole recombination in germanium

    International Nuclear Information System (INIS)

    Darken, L.S.; Jellison, G.E. Jr.

    1989-01-01

    The recombination kinetics of several centers (Zn - , Cu - , B - , CuH - 2 , CuH - x , Zn = , Cu = , and CuH = x ) in high-purity Ge have been measured as a function of temperature from 8 to 160 K by transient capacitance techniques and are significantly faster than expected from cascade theory. The cascade theory also gives the wrong temperature dependence, and the wrong z dependence. Instead, the data are generally fit by the expression N v /4pτ c congruent kT/h (p and τ c are, respectively, the free-hole concentration in the sample and the experimental mean capture time for a center)

  12. Temperature dependence of photovoltaic cells, modules, and systems

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Burdick, J.; Caiyem, Y. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    Photovoltaic (PV) cells and modules are often rated in terms of a set of standard reporting conditions defined by a temperature, spectral irradiance, and total irradiance. Because PV devices operates over a wide range of temperatures and irradiances, the temperature and irradiance related behavior must be known. This paper surveys the temperature dependence of crystalline and thin-film, state-of-the-art, research-size cells, modules, and systems measured by a variety of methods. The various error sources and measurement methods that contribute to cause differences in the temperature coefficient for a given cell or module measured with various methods are discussed.

  13. Calculated temperature dependence of elastic constants and phonon dispersion of hcp and bcc beryllium

    Science.gov (United States)

    Hahn, Steven; Arapan, Sergiu; Harmon, Bruce; Eriksson, Olle

    2011-03-01

    Conventional first principle methods for calculating lattice dynamics are unable to calculate high temperature thermophysical properties of materials containing modes that are entropically stabilized. In this presentation we use a relatively new approach called self-consistent ab initio lattice dynamics (SCAILD) to study the hcp to bcc transition (1530 K) in beryllium. The SCAILD method goes beyond the harmonic approximation to include phonon-phonon interactions and produces a temperature-dependent phonon dispersion. In the high temperature bcc structure, phonon-phonon interactions dynamically stabilize the N-point phonon. Fits to the calculated phonon dispersion were used to determine the temperature dependence of the elastic constants in the hcp and bcc phases. Work at the Ames Laboratory was supported by the Department of Energy-Basic Energy Sciences under Contract No. DE-AC02-07CH11358.

  14. Development of a temperature-dependent cyclic plasticity constitutive model for SUS304 steel

    International Nuclear Information System (INIS)

    Takahashi, Yukio

    1990-01-01

    Development of an accurate inelastic constitutive model is required to improve the accuracy of inelastic analysis for structural components used in the inelastic region. Based on two fundamental assumptions derived from physical interpretation of temperature dependency of the plastic deformation behavior of type 304 stainless steel, a temperature-dependent cyclic plastic constitutive model is constructed here. Particular emphasis is placed on the modeling of enhanced hardening caused by the dynamic strain aging effect observed in some temperature regimes. Constants and functions involved in the model are determined based on the deformation characteristics observed in the low-cycle fatigue tests conducted at room temperature through 600degC. Several comparisons of model predictions with experimental data show the effectiveness of the present model in non-isothermal condition as well as in isothermal condition between room temperature and 600degC. (author)

  15. Memory effects, two color percolation, and the temperature dependence of Mott variable-range hopping

    Science.gov (United States)

    Agam, Oded; Aleiner, Igor L.

    2014-06-01

    There are three basic processes that determine hopping transport: (a) hopping between normally empty sites (i.e., having exponentially small occupation numbers at equilibrium), (b) hopping between normally occupied sites, and (c) transitions between normally occupied and unoccupied sites. In conventional theories all these processes are considered Markovian and the correlations of occupation numbers of different sites are believed to be small (i.e., not exponential in temperature). We show that, contrary to this belief, memory effects suppress the processes of type (c) and manifest themselves in a subleading exponential temperature dependence of the variable-range hopping conductivity. This temperature dependence originates from the property that sites of type (a) and (b) form two independent resistor networks that are weakly coupled to each other by processes of type (c). This leads to a two-color percolation problem which we solve in the critical region.

  16. Unusual temperature dependence of the positron lifetime in a polymer of intrinsic microporosity

    International Nuclear Information System (INIS)

    Lima de Miranda, Rodrigo; Kruse, Jan; Raetzke, Klaus; Faupel, Franz; Fritsch, Detlev; Abetz, Volker; Budd, Peter M.; Selbie, James D.; McKeown, Neil B.; Ghanem, Bader S.

    2007-01-01

    The performance of polymeric membranes for gas separation is mainly determined by the free volume. Polymers of intrinsic microporosity are interesting due to the high abundance of accessible free volume. We performed measurements of the temperature dependence of the positron lifetime, generally accepted for investigation of free volume, in two polymers of intrinsic microporosity (PIM-1 and PIM-7) in the range from 143 to 523 K. The mean value of the free volume calculated from the ortho-positronium lifetime is in the range of typical values for high free volume polymers. However, the temperature dependence of the local free volume is non-monotonous in contrast to the macroscopic thermal expansion. The explanation is linked to the spirocenters in the polymer. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Temperature dependence of conductivity in high mobility MIS structures on a base of (001) silicon

    International Nuclear Information System (INIS)

    Vyrodov, E.A.; Dolgopolov, V.T.; Dorozhkin, C.I.; Zhitenev, N.B.

    1988-01-01

    Measurements of the temperature dependence of the conductivity of two-dimensional electrons in silicon MIS structures were carried out. It is shown that the observed dependence is well described by the equation σ(T) = σ(0)(1-Q(kT var-epsilon F )-P(kT/var-epsilon F )3/2 + O[(kT/var-epsilon F ) 2 ]). The variation of the coefficient Q with the density N S of the two-dimensional electrons is determined, and it is shown that the observed trend of the Q(s) curve is described by consideration of the temperature dependence of the dielectric function of a two-dimensional electron gas

  18. Temperature dependence of magnetically dead layers in ferromagnetic thin-films

    Directory of Open Access Journals (Sweden)

    M. Tokaç

    2017-11-01

    Full Text Available Polarized neutron reflectometry has been used to study interface magnetism and magnetic dead layers in model amorphous CoFeB:Ta alloy thin-film multilayers with Curie temperatures tuned to be below room-temperature. This allows temperature dependent variations in the effective magnetic thickness of the film to be determined at temperatures that are a significant fraction of the Curie temperature, which cannot be achieved in the material systems used for spintronic devices. In addition to variation in the effective magnetic thickness due to compositional grading at the interface with the tantalum capping layer, the key finding is that at the interface between ferromagnetic film and GaAs(001 substrate local interfacial alloying creates an additional magnetic dead-layer. The thickness of this magnetic dead-layer is temperature dependent, which may have significant implications for elevated-temperature operation of hybrid ferromagnetic metal-semiconductor spintronic devices.

  19. Temperature dependences of photoconductivity of CdHgTe crystals with photoactive inclusions

    International Nuclear Information System (INIS)

    Vlasenko, A.I.; Vlasenko, Z.K.

    1999-01-01

    Temperature dependences of life time τ and spectral characteristics of photoconductivity for Cd x Hg 1-x Te crystals (x = 0.2) with photoactive inclusions are investigated. It is shown that the N-type character of effective lifetime temperature dependences in nonhomogeneous crystals, in particular, its sharp temperature activation in the region of transition from the impurity to the intrinsic conductivity is determined by not the Shockley-Read mechanism, but by the interband impact mechanism with changing effective geometrical sizes of recombination active regions under temperature increase. Within the frames of this model the smoothing of the non-monotone character of the photoconductivity spectral characteristics in the region of fundamental absorption under the heating is explained. The calculation results that are in qualitative agreement with the experimental data are presented [ru

  20. Identification of the sex-determining locus in grass puffer (Takifugu niphobles) provides evidence for sex-chromosome turnover in a subset of Takifugu species

    Science.gov (United States)

    Atsumi, Kazufumi; Kamiya, Takashi; Nozawa, Aoi; Aoki, Yuma; Tasumi, Satoshi; Koyama, Takashi; Nakamura, Osamu; Suzuki, Yuzuru

    2018-01-01

    There is increasing evidence for frequent turnover in sex chromosomes in vertebrates. Yet experimental systems suitable for tracing the detailed process of turnover are rare. In theory, homologous turnover is possible if the new sex-determining locus is established on the existing sex-chromosome. However, there is no empirical evidence for such an event. The genus Takifugu includes fugu (Takifugu rubripes) and its two closely-related species whose sex is most likely determined by a SNP at the Amhr2 locus. In these species, males are heterozygous, with G and C alleles at the SNP site, while females are homozygous for the C allele. To determine if a shift in the sex-determining locus occurred in another member of this genus, we used genetic mapping to characterize the sex-chromosome systems of Takifugu niphobles. We found that the G allele of Amhr2 is absent in T. niphobles. Nevertheless, our initial mapping suggests a linkage between the phenotypic sex and the chromosome 19, which harbors the Amhr2 locus. Subsequent high-resolution analysis using a sex-reversed fish demonstrated that the sex-determining locus maps to the proximal end of chromosome 19, far from the Amhr2 locus. Thus, it is likely that homologous turnover involving these species has occurred. The data also showed that there is a male-specific reduction of recombination around the sex-determining locus. Nevertheless, no evidence for sex-chromosome differentiation was detected: the reduced recombination depended on phenotypic sex rather than genotypic sex; no X- or Y-specific maker was obtained; the YY individual was viable. Furthermore, fine-scale mapping narrowed down the new sex-determining locus to the interval corresponding to approximately 300-kb of sequence in the fugu genome. Thus, T. niphobles is determined to have a young and small sex-determining region that is suitable for studying an early phase of sex-chromosome evolution and the mechanisms underlying turnover of sex chromosome. PMID

  1. B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes.

    Directory of Open Access Journals (Sweden)

    Kohta Yoshida

    2011-08-01

    Full Text Available The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85% in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes.

  2. Direct LAMP Assay without Prior DNA Purification for Sex Determination of Papaya

    Directory of Open Access Journals (Sweden)

    Chi-Chu Tsai

    2016-09-01

    Full Text Available Papaya (Carica papaya L. is an economically important tropical fruit tree with hermaphrodite, male and female sex types. Hermaphroditic plants are the major type used for papaya production because their fruits have more commercial advantages than those of female plants. Sex determination of the seedlings, or during the early growth stages, is very important for the papaya seedling industry. Thus far, the only method for determining the sex type of a papaya at the seedling stage has been DNA analysis. In this study, a molecular technique—based on DNA analysis—was developed for detecting male-hermaphrodite-specific markers to examine the papaya’s sex type. This method is based on the loop-mediated isothermal amplification (LAMP and does not require prior DNA purification. The results show that the method is an easy, efficient, and inexpensive way to determine a papaya’s sex. This is the first report on the LAMP assay, using intact plant materials-without DNA purification-as samples for the analysis of sex determination of papaya. We found that using high-efficiency DNA polymerase was essential for successful DNA amplification, using trace intact plant material as a template DNA source.

  3. Drosophila as a model for the study of sex determination in anopheline and aedine mosquitoes

    International Nuclear Information System (INIS)

    Pannuti, A.; Kocacitak, T.; Lucchesi, J.C.

    2000-01-01

    Sterile insect technique control strategies consist of releasing laboratory produced male insects that have been sterilised by irradiation. These strategies require the production of massive quantities of males. Population-replacement strategies rely on the genetically engineered interruption of that portion of the malaria parasite's life cycle that occurs in the mosquito. This could be achieved by the inundative introduction of transformed males or the more limited introduction of males carrying an infective agent capable of driving a parasite-inhibiting transgene into the vector population. Once again, the release of genetically engineered males would require genetic systems for their mass production. Mass production of males can be accomplished most effectively through genetic sexing techniques. Genetic sexing can be achieved by identifying the key steps in the genetic regulation of sex differentiation and by modifying one or more of these steps so that their execution would result in sex-specific lethality. As the necessary and seminal first step towards this goal, we set out to identify and isolate a gene whose primary transcript is processed differently in males and females of Anopheles gambiae Giles. A survey of sex determination among insects reveals a vast array of different mechanisms. Our understanding of these mechanisms consists only of information derived from classical cytological and genetic studies. Using the knowledge derived from the study of Drosophila, it has been possible to discern a fundamental pattern in the sex determining mechanisms of many diverse insect species (Noethiger and Steinmann-Zwicky 1985). The challenge now, is to determine if there has been an evolutionary conservation of the genes responsible for the fundamental pattern, i.e., if the molecular mechanisms that underlie sex determination in Drosophila are the same in other insects of interest or if in these insects, the apparent fundamental pattern is achieved by completely

  4. Use of radioimmunoassay procedures for the determination of sex hormones in animal tissues

    International Nuclear Information System (INIS)

    Hoffmann, B.

    1983-01-01

    Radioimmunoassay methods for the determination of sex steroids and other compounds with sex hormone-like activities in various edible animal tissues and endocrine glands have been developed. Reliability of these methods, allowing quantification in a range of 10 -11 M, has been adequately demonstrated. When applied to monitoring residues of anabolic sex hormones in edible tissues of veal calves, physiological baseline levels of some endogenous ''anabolic'' steroids (like testosterone, oestrogens) were established; in the case of xenobiotics residues at the scheduled time of slaughter could be quantified (trenbolone) and a regulatory method to implement the ban of diethylstilbestrol was introduced. (author)

  5. Use of radioimmunoassay procedures for the determination of sex hormones in animal tissues

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, B. (Institut fuer Veterinaermedizin des Bundesgesundheitsamtes (Robert von Ostertag-Institut), Berlin (Germany, F.R.))

    1983-07-01

    Radioimmunoassay methods for the determination of sex steroids and other compounds with sex hormone-like activities in various edible animal tissues and endocrine glands have been developed. Reliability of these methods, allowing quantification in a range of 10/sup -11/ M, has been adequately demonstrated. When applied to monitoring residues of anabolic sex hormones in edible tissues of veal calves, physiological baseline levels of some endogenous ''anabolic'' steroids (like testosterone, oestrogens) were established; in the case of xenobiotics residues at the scheduled time of slaughter could be quantified (trenbolone) and a regulatory method to implement the ban of diethylstilbestrol was introduced.

  6. Temperature dependent dynamic susceptibility calculations for itinerant ferromagnets

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, J. F.

    1980-10-01

    Inelastic neutron scattering experiments have revealed a variety of interesting and unusual phenomena associated with the spin dynamics of the 3-d transition metal ferromagnets nickel and iron. An extensive series of calculations based on the itinerant electron formalism has demonstrated that the itinerant model does provide an excellent quantitative as well as qualitative description of the measured spin dynamics of both nickel and iron at low temperatures. Recent angular photo emission experiments have indicated that there is a rather strong temperature dependence of the electronic spin-splitting which, from relatively crude arguments, appears to be inconsistent with neutron scattering results. In order to investigate this point and also the origin of spin-wave renormalization, a series of calculations of the dynamic susceptibility of nickel and iron has been undertaken. The results of these calculations indicate that a discrepancy exists between the interpretations of neutron and photoemission experimental results regarding the temperature dependence of the spin-splitting of the electronic energy bands.

  7. Temperature dependence of piezoelectric properties for textured SBN ceramics.

    Science.gov (United States)

    Kimura, Masahiko; Ogawa, Hirozumi; Kuroda, Daisuke; Sawada, Takuya; Higuchi, Yukio; Takagi, Hiroshi; Sakabe, Yukio

    2007-12-01

    Temperature dependences of piezoelectric properties were studied for h001i textured ceramics of bismuth layer-structured ferroelectrics, SrBi(2)Nb(2)O(9) (SBN). The textured ceramics with varied orientation degrees were fabricated by templated, grain-growth method, and the temperature dependences of resonance frequency were estimated. Excellent temperature stability of resonance frequency was obtained for the 76% textured ceramics. The resonance frequency of the 76% textured specimens varied almost linearly over a wide temperature range. Therefore, the variation was slight, even in a high temperature region above 150 degrees C. Temperature stability of a quartz crystal oscillator is generally higher than that of a ceramic resonator around room temperature. The variation of resonance frequency for the 76% textured SrBi(2)Nb(2)O(9) was larger than that of oscillation frequency for a typical quartz oscillator below 150 degrees C also in this study. However, the variation of the textured SrBi(2)Nb(2)O(9) was smaller than that of the quartz oscillator over a wide temperature range from -50 to 250 degrees C. Therefore, textured SrBi(2)Nb(2)O(9) ceramics is a major candidate material for the resonators used within a wide temperature range.

  8. Temperature-dependent imaging of living cells by AFM

    International Nuclear Information System (INIS)

    Espenel, Cedric; Giocondi, Marie-Cecile; Seantier, Bastien; Dosset, Patrice; Milhiet, Pierre-Emmanuel; Le Grimellec, Christian

    2008-01-01

    Characterization of lateral organization of plasma membranes is a prerequisite to the understanding of membrane structure-function relationships in living cells. Lipid-lipid and lipid-protein interactions are responsible for the existence of various membrane microdomains involved in cell signalization and in numerous pathologies. Developing approaches for characterizing microdomains associate identification tools like recognition imaging with high-resolution topographical imaging. Membrane properties are markedly dependent on temperature. However, mesoscopic scale topographical information of cell surface in a temperature range covering most of cell biology experimentation is still lacking. In this work we have examined the possibility of imaging the temperature-dependent behavior of eukaryotic cells by atomic force microscopy (AFM). Our results establish that the surface of living CV1 kidney cells can be imaged by AFM, between 5 and 37 deg. C, both in contact and tapping modes. These first temperature-dependent data show that large cell structures appeared essentially stable at a microscopic scale. On the other hand, as shown by contact mode AFM, the surface was highly dynamic at a mesoscopic scale, with marked changes in apparent topography, friction, and deflection signals. When keeping the scanning conditions constant, a progressive loss in the image contrast was however observed, using tapping mode, on decreasing the temperature

  9. Temperature-dependent structure evolution in liquid gallium

    International Nuclear Information System (INIS)

    Xiong, L.H.; Wang, X.D.; Yu, Q.; Zhang, H.; Zhang, F.; Sun, Y.; Cao, Q.P.; Xie, H.L.; Xiao, T.Q.; Zhang, D.X.; Wang, C.Z.; Ho, K.M.

    2017-01-01

    Temperature-dependent atomistic structure evolution of liquid gallium (Ga) has been investigated by using in situ high energy X-ray diffraction experiment and ab initio molecular dynamics simulation. Both experimental and theoretical results reveal the existence of a liquid structural change around 1000 K in liquid Ga. Below and above this temperature the liquid exhibits differences in activation energy for self-diffusion, temperature-dependent heat capacity, coordination numbers, density, viscosity, electric resistivity and thermoelectric power, which are reflected from structural changes of the bond-orientational order parameter Q_6, fraction of covalent dimers, averaged string length and local atomic packing. This finding will trigger more studies on the liquid-to-liquid crossover in metallic melts. - Graphical abstract: Atomistic structure evolution of liquid gallium has been investigated by using in situ high energy X-ray diffraction and ab initio molecular dynamics simulations, which both demonstrate the existence of a liquid structural change together with reported density, viscosity, electric resistivity and absolute thermoelectric power data.

  10. Temperature-dependent electrical property transition of graphene oxide paper

    International Nuclear Information System (INIS)

    Huang Xingyi; Jiang Pingkai; Zhi Chunyi; Golberg, Dmitri; Bando, Yoshio; Tanaka, Toshikatsu

    2012-01-01

    Reduction of graphene oxide is primarily important because different reduction methods may result in graphene with totally different properties. For systematically exploring the reduction of graphene oxide, studies of the temperature-dependent electrical properties of graphene oxide (GO) are urgently required. In this work, for the first time, broadband dielectric spectroscopy was used to carry out an in situ investigation on the transition of the electrical properties of GO paper from −40 to 150 °C. The results clearly reveal a very interesting four-stage transition of electrical properties of GO paper with increasing temperature: insulator below 10 °C (stage 1), semiconductor at between 10 and 90 °C (stage 2), insulator at between 90 and 100 °C (stage 3), and semiconductor again at above 100 °C (stage 4). Subsequently, the transition mechanism was discussed in combination with detailed dielectric properties, microstructure and thermogravimetric analyses. It is suggested that the temperature-dependent transition of electronic properties of GO is closely associated with the ion mobility, water molecules removal and the reduction of GO in the GO paper. Most importantly, the present work clearly demonstrates the reduction of GO paper starts at above 100 °C. (paper)

  11. Temperature dependence and the moving species during ion mixing

    International Nuclear Information System (INIS)

    Xia, W.; Fernandes, M.; Hewett, C.A.; Lau, S.S.; Poker, D.B.; Biersack, J.P.

    1988-01-01

    In this paper, the authors review the experimental observations of the temperature dependence and the moving species in ion mixing, emphasizing the metal-semiconductor systems. Ion mixing is the combined effect of two components. One component is temperature independent and is primarily due to events in the prompt regime, the other component is temperature dependent and has the characteristics of the associated thermal reactions. The moving species during ion mixing are influenced by collisional effects, either due to secondary recoils, or due to local hot spots, or both. The secondary recoil concept is consistent with experimental observations that the motion of the lighter element in a bilayer sample is enhanced. There is ample evidence that while the a thermal regime is caused by particle-solid interactions, thermodynamical forces are important in deciding the magnitude of mixing. In the thermally activated regime, the ion induced reaction product should be influenced by the heats of formation of various compounds. We also indicate areas where satisfactory explanations are not available at present

  12. Temperature dependence of carbon isotope fractionation in CAM plants

    International Nuclear Information System (INIS)

    Deleens, E.; Treichel, I.; O'Leary, M.H.

    1985-01-01

    The carbon isotope fractionation associated with nocturnal malic acid synthesis in Kalanchoë daigremontiana and Bryophyllum tubiflorum was calculated from the isotopic composition of carbon-4 of malic acid, after appropriate corrections. In the lowest temperature treatment (17 degrees C nights, 23 degrees C days), the isotope fractionation for both plants is -4 per thousand (that is, malate is enriched in (13)C relative to the atmosphere). For K. daigremontiana, the isotope fractionation decreases with increasing temperature, becoming approximately 0 per thousand at 27 degrees C/33 degrees C. Detailed analysis of temperature effects on the isotope fractionation indicates that stomatal aperture decreases with increasing temperature and carboxylation capacity increases. For B. tubiflorum, the temperature dependence of the isotope fractionation is smaller and is principally attributed to the normal temperature dependences of the rates of diffusion and carboxylation steps. The small change in the isotopic composition of remaining malic acid in both species which is observed during deacidification indicates that malate release, rather than decarboxylation, is rate limiting in the deacidification process

  13. Temperature dependence of carbon isotope fractionation in CAM plants

    Energy Technology Data Exchange (ETDEWEB)

    Deleens, E.; Treichel, I.; O' Leary, M.H.

    1985-09-01

    The carbon isotope fractionation associated with nocturnal malic acid synthesis in Kalanchoe daigremontiana and Bryophyllum tubiflorum was calculated from the isotopic composition of carbon-4 of malic acid, after appropriate corrections. In the lowest temperature treatment (17/sup 0/C nights, 23/sup 0/C days), the isotope fractionation for both plants is -4% per thousand (that is, malate is enriched in /sup 13/C relative to the atmosphere). For K. daigremontiana, the isotope fractionation decreases with increasing temperature, becoming approximately 0% per thousand at 27/sup 0/C/33/sup 0/C. Detailed analysis of temperature effects on the isotope fractionation indicates that stomatal aperture decreases with increasing temperature and carboxylation capacity increases. For B. tubiflorum, the temperature dependence of the isotope fractionation is smaller and is principally attributed to the normal temperature dependences of the rates of diffusion and carboxylation steps. The small change in the isotopic composition of remaining malic acid in both species which is observed during deacidification indicates that malate release, rather than decarboxylation, is rate limiting in the deacidification process. 28 references, 1 figure, 4 tables.

  14. Identification of Sex-determining Loci in Pacific White Shrimp Litopeneaus vannamei Using Linkage and Association Analysis.

    Science.gov (United States)

    Yu, Yang; Zhang, Xiaojun; Yuan, Jianbo; Wang, Quanchao; Li, Shihao; Huang, Hao; Li, Fuhua; Xiang, Jianhai

    2017-06-01

    The Pacific white shrimp Litopenaeus vannamei is a predominant aquaculture shrimp species in the world. Like other animals, the L. vannamei exhibited sexual dimorphism in growth trait. Mapping of the sex-determining locus will be very helpful to clarify the sex determination system and further benefit the shrimp aquaculture industry towards the production of mono-sex stocks. Based on the data used for high-density linkage map construction, linkage-mapping analysis was conducted. The sex determination region was mapped in linkage group (LG) 18. A large region from 0 to 21.205 cM in LG18 showed significant association with sex. However, none of the markers in this region showed complete association with sex in the other populations. So an association analysis was designed using the female parent, pool of female progenies, male parent, and pool of male progenies. Markers were de novo developed and those showing significant differences between female and male pools were identified. Among them, three sex-associated markers including one fully associated marker were identified. Integration of linkage and association analysis showed that the sex determination region was fine-mapped in a small region along LG18. The identified sex-associated marker can be used for the sex detection of this species at genetic level. The fine-mapped sex-determining region will contribute to the mapping of sex-determining gene and help to clarify sex determination system for L. vannamei.

  15. QTL Mapping of Sex Determination Loci Supports an Ancient Pathway in Ants and Honey Bees.

    Directory of Open Access Journals (Sweden)

    Misato O Miyakawa

    2015-11-01

    Full Text Available Sex determination mechanisms play a central role in life-history characteristics, affecting mating systems, sex ratios, inbreeding tolerance, etc. Downstream components of sex determination pathways are highly conserved, but upstream components evolve rapidly. Evolutionary dynamics of sex determination remain poorly understood, particularly because mechanisms appear so diverse. Here we investigate the origins and evolution of complementary sex determination (CSD in ants and bees. The honey bee has a well-characterized CSD locus, containing tandemly arranged homologs of the transformer gene [complementary sex determiner (csd and feminizer (fem]. Such tandem paralogs appear frequently in aculeate hymenopteran genomes. However, only comparative genomic, but not functional, data support a broader role for csd/fem in sex determination, and whether species other than the honey bee use this pathway remains controversial. Here we used a backcross to test whether csd/fem acts as a CSD locus in an ant (Vollenhovia emeryi. After sequencing and assembling the genome, we computed a linkage map, and conducted a quantitative trait locus (QTL analysis of diploid male production using 68 diploid males and 171 workers. We found two QTLs on separate linkage groups (CsdQTL1 and CsdQTL2 that jointly explained 98.0% of the phenotypic variance. CsdQTL1 included two tandem transformer homologs. These data support the prediction that the same CSD mechanism has indeed been conserved for over 100 million years. CsdQTL2 had no similarity to CsdQTL1 and included a 236-kb region with no obvious CSD gene candidates, making it impossible to conclusively characterize it using our data. The sequence of this locus was conserved in at least one other ant genome that diverged >75 million years ago. By applying QTL analysis to ants for the first time, we support the hypothesis that elements of hymenopteran CSD are ancient, but also show that more remains to be learned about the

  16. Sex Determination of Japanese Quails (Coturnix Coturnix Japonica using with Zoometric Measurements

    Directory of Open Access Journals (Sweden)

    Tülin Çiçek Rathert

    2017-09-01

    Full Text Available The difficulty of sex determination in most poultry species causes significant financial losses for poultry production as birds cannot be separated at early stages of growth for meat or egg production. Therefore it is important to determine bird’s sex with zoometric parameters. This study was carried out to determine the sex of Japanese quails with zoometric measurements, such as live weight, body length, chest depth and chest width. Eighty-eight male and female Japanese quail chicks were used individually for live weight, chest depth (mm, chest width (mm and body length (mm with using digital scaled balance and caliper for every week over a period of six weeks. The weekly collected data were applied to t test for estimating the sex discrimination. The Pearson’s correlation was applied for examining the interrelationship between sex and biometric traits. The results indicated that there was a significant positive correlation between live weight and body length beginning with the 2nd week. Therefore, zoometric measurement of these body traits is suitable for discriminating the sex of Japanese quails in early phase of life.

  17. Sex determination using facial linear dimensions and angles among Hausa population of Kano State, Nigeria

    Directory of Open Access Journals (Sweden)

    Lawan H. Adamu

    2016-12-01

    Full Text Available The aim of the study was to determine sexual dimorphism as well as to predict sex using facial linear dimensions and angles among Hausas of Kano state Nigeria. A total of 283 subjects comprising 147 males and 136 females age range 18–25 years participated. Photographs methods were used to capture the face. Independent sample t-test was used to test for sex differences in the variables. Binary logistic regression was applied to obtain a predicting equation (BLR model for sex. The predicted probabilities of BLR were analyzed using receiver operating characteristic curve. The results showed that all the facial linear dimensions showed significance sexual dimorphism except interocular distance, upper facial width, philtrum length, lower vermilion width, left and right orbital width. With regards to sex prediction, upper facial height was the single best predictor of sex with an accuracy of 76.2% and 24–33% contribution to the prediction. However, the percentage accuracy increased to 91% when six variables were pooled together in the equations. For facial angles, only nasion and aperture modified angle did not show significant gender differences. However, in the variables with significant sexual dimorphism only nasomental angle showed a significant level of sex prediction with an accuracy of 70.3%. In conclusion, sex discrimination using facial linear dimensions and angles was well established in this study. The sex of an individual of Hausa ethnic group can be determined using facial linear dimensions. Dispite sexual dimorphsm shown by facial angles, only nasomental angle was good discriminator of sex.

  18. Sex determination in the haplodiploid wasp Nasonia vitripennis (Hymenoptera Chalcidoidea) : A critical consideration of models and evidence

    NARCIS (Netherlands)

    Beukeboom, Leo W.; Kamping, Albert; van de Zande, Louis

    Sex determining mechanisms are highly diverse. Like all Hymenoptera, the parasitic wasp Nasonia vitripennis reproduces by haplodiploidy: males are haploid and females are diploid. Sex in Nasonia is not determined by complementary alleles at sex loci. Evidence for several alternative models is

  19. Estimation of the temperature dependent interaction between uncharged point defects in Si

    Energy Technology Data Exchange (ETDEWEB)

    Kamiyama, Eiji [Department of Communication Engineering, Okayama Prefectural University, 111 Kuboki, Soja-shi, Okayama-ken 719-1197 (Japan); GlobalWafers Japan Co., Ltd., 30 Soya, Hadano, Kanagawa, 257-8566 (Japan); Vanhellemont, Jan [Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, Ghent B-9000 (Belgium); Sueoka, Koji [Department of Communication Engineering, Okayama Prefectural University, 111 Kuboki, Soja-shi, Okayama-ken 719-1197 (Japan)

    2015-01-15

    A method is described to estimate the temperature dependent interaction between two uncharged point defects in Si based on DFT calculations. As an illustration, the formation of the uncharged di-vacancy V{sub 2} is discussed, based on the temperature dependent attractive field between both vacancies. For that purpose, all irreducible configurations of two uncharged vacancies are determined, each with their weight given by the number of equivalent configurations. Using a standard 216-atoms supercell, nineteen irreducible configurations of two vacancies are obtained. The binding energies of all these configurations are calculated. Each vacancy is surrounded by several attractive sites for another vacancy. The obtained temperature dependent of total volume of these attractive sites has a radius that is closely related with the capture radius for the formation of a di-vacancy that is used in continuum theory. The presented methodology can in principle also be applied to estimate the capture radius for pair formation of any type of point defects.

  20. Temperature dependence of bulk respiration of crop stands. Measurement and model fitting

    International Nuclear Information System (INIS)

    Tani, Takashi; Arai, Ryuji; Tako, Yasuhiro

    2007-01-01

    The objective of the present study was to examine whether the temperature dependence of respiration at a crop-stand scale could be directly represented by an Arrhenius function that was widely used for representing the temperature dependence of leaf respiration. We determined temperature dependences of bulk respiration of monospecific stands of rice and soybean within a range of the air temperature from 15 to 30degC using large closed chambers. Measured responses of respiration rates of the two stands were well fitted by the Arrhenius function (R 2 =0.99). In the existing model to assess the local radiological impact of the anthropogenic carbon-14, effects of the physical environmental factors on photosynthesis and respiration of crop stands are not taken into account for the calculation of the net amount of carbon per cultivation area in crops at harvest which is the crucial parameter for the estimation of the activity concentration of carbon-14 in crops. Our result indicates that the Arrhenius function is useful for incorporating the effect of the temperature on respiration of crop stands into the model which is expected to contribute to a more realistic estimate of the activity concentration of carbon-14 in crops. (author)

  1. Observing the temperature dependent transition of the GP2 peptide using terahertz spectroscopy.

    Directory of Open Access Journals (Sweden)

    Yiwen Sun

    Full Text Available The GP2 peptide is derived from the Human Epidermal growth factor Receptor 2 (HER2/nue, a marker protein for breast cancer present in saliva. In this paper we study the temperature dependent behavior of hydrated GP2 at terahertz frequencies and find that the peptide undergoes a dynamic transition between 200 and 220 K. By fitting suitable molecular models to the frequency response we determine the molecular processes involved above and below the transition temperature (T(D. In particular, we show that below T(D the dynamic transition is dominated by a simple harmonic vibration with a slow and temperature dependent relaxation time constant and that above T(D, the dynamic behavior is governed by two oscillators, one of which has a fast and temperature independent relaxation time constant and the other of which is a heavily damped oscillator with a slow and temperature dependent time constant. Furthermore a red shifting of the characteristic frequency of the damped oscillator was observed, confirming the presence of a non-harmonic vibration potential. Our measurements and modeling of GP2 highlight the unique capabilities of THz spectroscopy for protein characterization.

  2. Modeling and Compensating Temperature-Dependent Non-Uniformity Noise in IR Microbolometer Cameras

    Directory of Open Access Journals (Sweden)

    Alejandro Wolf

    2016-07-01

    Full Text Available Images rendered by uncooled microbolometer-based infrared (IR cameras are severely degraded by the spatial non-uniformity (NU noise. The NU noise imposes a fixed-pattern over the true images, and the intensity of the pattern changes with time due to the temperature instability of such cameras. In this paper, we present a novel model and a compensation algorithm for the spatial NU noise and its temperature-dependent variations. The model separates the NU noise into two components: a constant term, which corresponds to a set of NU parameters determining the spatial structure of the noise, and a dynamic term, which scales linearly with the fluctuations of the temperature surrounding the array of microbolometers. We use a black-body radiator and samples of the temperature surrounding the IR array to offline characterize both the constant and the temperature-dependent NU noise parameters. Next, the temperature-dependent variations are estimated online using both a spatially uniform Hammerstein-Wiener estimator and a pixelwise least mean squares (LMS estimator. We compensate for the NU noise in IR images from two long-wave IR cameras. Results show an excellent NU correction performance and a root mean square error of less than 0.25 ∘ C, when the array’s temperature varies by approximately 15 ∘ C.

  3. Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre.

    Science.gov (United States)

    Smit, Jacoba E; Hanekom, Tania; Hanekom, Johan J

    2009-08-01

    The objective of this study was to determine if a recently developed human Ranvier node model, which is based on a modified version of the Hodgkin-Huxley model, could predict the excitability behaviour in human peripheral sensory nerve fibres with diameters ranging from 5.0 to 15.0 microm. The Ranvier node model was extended to include a persistent sodium current and was incorporated into a generalised single cable nerve fibre model. Parameter temperature dependence was included. All calculations were performed in Matlab. Sensory nerve fibre excitability behaviour characteristics predicted by the new nerve fibre model at different temperatures and fibre diameters compared well with measured data. Absolute refractory periods deviated from measured data, while relative refractory periods were similar to measured data. Conduction velocities showed both fibre diameter and temperature dependence and were underestimated in fibres thinner than 12.5 microm. Calculated strength-duration time constants ranged from 128.5 to 183.0 micros at 37 degrees C over the studied nerve fibre diameter range, with chronaxie times about 30% shorter than strength-duration time constants. Chronaxie times exhibited temperature dependence, with values overestimated by a factor 5 at temperatures lower than body temperature. Possible explanations include the deviated absolute refractory period trend and inclusion of a nodal strangulation relationship.

  4. Sample holder for studying temperature dependent particle guiding

    International Nuclear Information System (INIS)

    Bereczky, R.J.; Toekesi, K.; Kowarik, G.; Aumayr, F.

    2011-01-01

    Complete text of publication follows. The so called guiding effect is a complex process involving the interplay of a large number of charged particles with a solid. Although many research groups joined this field and carried out various experiments with insulator capillaries many details of the interactions are still unknown. We investigated the temperature dependence of the guiding since it opens new possibilities both for a fundamental understanding of the guiding phenomenon and for applications. For the temperature dependent guiding experiments a completely new heatable sample holder was designed. We developed and built such a heatable sample holder to make accurate and reproducible studies of the temperature dependence of the ion guiding effect possible. The target holder (for an exploded view see Fig. 1) consists of two main parts, the front and the back plates. The two plates of the sample holder, which function as an oven, are made of copper. These parts surround the capillary in order to guarantee a uniform temperature along the whole tube. The temperature of the copper parts is monitored by a K-Type thermocouple. Stainless steel coaxial heaters surrounding the oven are used for heating. The heating power up to a few watts is regulated by a PID controller. Cooling of the capillary is achieved by a copper feed-through connected to a liquid nitrogen bath outside the UHV chamber. This solution allows us to change the temperature of the sample from -30 deg C up to 90 deg C. Our experiments with this newly developed temperature regulated capillary holder show that the glass temperature (i.e. conductivity) can be used to control the guiding properties of the glass capillary and adjust the conditions from guiding at room temperature to simple geometrical transmission at elevated temperatures. This holds the promise to investigate the effect of conductivity on particle transport (build-up and removal of charge patches) through capillaries in more details

  5. Ferromagnetism and temperature-dependent electronic structure in metallic films

    International Nuclear Information System (INIS)

    Herrmann, T.

    1999-01-01

    In this work the influence of the reduced translational symmetry on the magnetic properties of thin itinerant-electron films and surfaces is investigated within the strongly correlated Hubbard model. Firstly, the possibility of spontaneous ferromagnetism in the Hubbard model is discussed for the case of systems with full translational symmetry. Different approximation schemes for the solution of the many-body problem of the Hubbard model are introduced and discussed in detail. It is found that it is vital for a reasonable description of spontaneous ferromagnetism to be consistent with exact results concerning the general shape of the single-electron spectral density in the limit of strong Coulomb interaction between the electrons. The temperature dependence of the ferromagnetic solutions is discussed in detail by use of the magnetization curves as well as the spin-dependent quasi particle spectrum. For the investigation of thin films and surfaces the approximation schemes for the bulk system have to be generalized to deal with the reduced translational symmetry. The magnetic behavior of thin Hubbard films is investigated by use of the layer dependent magnetization as a function of temperature as well as the thickness of the film. The Curie-temperature is calculated as a function of the film thickness. Further, the magnetic stability at the surface is discussed in detail. Here it is found that for strong Coulomb interaction the magnetic stability at finite temperatures is reduced at the surface compared to the inner layers. This observation clearly contradicts the well-known Stoner picture of band magnetism and can be explained in terms of general arguments which are based on exact results in the limit of strong Coulomb interaction. The magnetic behavior of the Hubbard films can be analyzed in detail by inspecting the local quasi particle density of states as well as the wave vector dependent spectral density. The electronic structure is found to be strongly spin

  6. Sex determination in femurs of modern Egyptians: A comparative study between metric measurements and SRY gene detection

    Directory of Open Access Journals (Sweden)

    Iman F. Gaballah

    2014-12-01

    Conclusion: The SRY gene detection method for sex determination is quick and simple, requiring only one PCR reaction. It corroborates the results obtained from anatomical measurements and further confirms the sex of the femur bone in question.

  7. Missing female fetus: a micro level investigation of sex determination in a periurban area of Northern India.

    Science.gov (United States)

    Ghosh, Rohini; Sharma, Arun Kumar

    2012-01-01

    A micro-level investigation of 983 pregnant women (aged 15-49 years) regarding sex determination and associated factors was carried out in a periurban region of Northern India. Among the women surveyed, 183 chose to use sex determination. The highest percentage of sex determination was among 30-39-year-old women, and general caste and family size were two risk factors associated with sex determination. Correcting imbalances in sex ratios at birth is a complex issue without easy answers, especially in patriarchal societies. Apart from raising awareness among decisionmakers, property rights in favor of women and strict vigilance and record of registration of ultrasound machines are necessary.

  8. Characterization and expression profile of the ovarian cytochrome P-450 aromatase (cyp19A1) gene during thermolabile sex determination in Pejerrey, Odontesthes bonariensis

    Science.gov (United States)

    Karube, M.; Fernandino, J.I.; Strobl-Mazzulla, P.; Strussmann, C.A.; Yoshizaki, G.; Somoza, G.M.; Patino, R.

    2007-01-01

    Cytochrome P450 aromatase (cyp19) is an enzyme that catalyzes the conversion of androgens to estrogens and may play a role in temperature- dependent sex determination (TSD) of reptiles, amphibians, and fishes. In this study, the ovarian P450 aromatase form (cyp19A1) of pejerrey Odontesthes bonariensis, a teleost with marked TSD, was cloned and its expression profile evaluated during gonadal differentiation at feminizing (17??C, 100% females), mixed-sex producing (24 and 25??C, 73.3 and 26.7% females, respectively), and masculinizing (29??C, 0% females) temperatures. The deduced cyp19A1 amino acid sequence shared high identity (>77.8%) with that from other teleosts but had low identity (<61.8%) with brain forms (cyp19A2), including that of pejerrey itself. The tissue distribution analysis of cyp19A1 mRNA in adult fish revealed high expression in the ovary. Semi-quantitative reverse transcription polymerase chain reaction analysis of the bodies of larvae revealed that cyp19A1 expression increased before the appearance of the first histological signs of ovarian differentiation at the feminizing temperature but remained low at the masculinizing temperature. The expression levels at mixed-sex producing temperatures were bimodal rather than intermediate, showing low and high modal values similar to those at the feminizing and masculinizing temperatures, respectively. The population percentages of high and low expression levels at intermediate temperatures were proportional to the percentage of females and males, respectively, and high levels were first observed at about the time of sex differentiation of females. These results suggest that cyp19A1 is involved in the process of ovarian formation and possibly also in the TSD of pejerrey. ?? 2007 Wiley-Liss, Inc.

  9. Determination of sex-ratio by birth order in an urban community in Manipur.

    Science.gov (United States)

    Brogen, Akoijam S; Shantibala, K; Rajkumari, Bishwalata; Laishram, Jalina

    2009-01-01

    To determine the sex ratio by birth order and to assess the sex preference of the couples in an urban community. A cross sectional study, in an urban community in Manipur, was conducted among the currently married couples. Data on background characteristics of the couple, family pedigree chart (of the offspring) including history of abortion, stillbirth, death of child of the couple, sex preference and Pre-natal Diagnostic Techniques (Regulation and Prevention of Misuse) Act [PNDT Act] were collected through a structured interview. Data were analyzed using descriptive and chi-square statistics. There were a total of 1777 births to the 855 couples interviewed. There were 900 females per 1000 males for the 1st birth order but the sex ratio was favorable towards females in the 2nd, 3rd and 4th birth orders. Among both the husbands and wives, being more educated was significantly associated (p<0.05) with preferring lesser number of children, using new technology for sex selection and having heard of the PNDT Act. Majority of those who wanted to use new technology for sex selection (128, 56.6%) preferred to have male child. Sex ratio in this community was favorable towards females, though it was less among the first born babies.

  10. Sex determination and disorders of sex development according to the revised nomenclature and classification in 46,XX individuals.

    Science.gov (United States)

    Kousta, Eleni; Papathanasiou, Asteroula; Skordis, Nicos

    2010-01-01

    There have been considerable advances concerning understanding of the early and later stages of ovarian development; a number of genes have been implicated and their mutations have been associated with developmental abnormalities. The most important genes controlling the initial phase of gonadal development, identical in females and males, are Wilms' tumor suppressor 1 (WT1) and steroidogenic factor 1 (SF1). Four genes are likely to be involved in the subsequent stages of ovarian development (WNT4, DAX1, FOXL2 and RSPO1), but none is yet proven to be the ovarian determining factor. Changes in nomenclature and classification were recently proposed in order to incorporate genetic advances and substitute gender-based diagnostic labels in terminology. The term "disorders of sex development" (DSD) is proposed to substitute the previous term "intersex disorders". Three main categories have been used to describe DSD in the 46,XX individual: 1) disorders of gonadal (ovarian) development: ovotesticular DSD, previously named true hermaphroditism, testicular DSD, previously named XX males, and gonadal dysgenesis; 2) disorders related to androgen excess (congenital adrenal hyperplasia, aromatase deficiency and P450 oxidoreductase deficiency); and 3) other rare disorders. In this mini-review, recent advances concerning development of the genital system in 46,XX individuals and related abnormalities are discussed. Basic embryology of the ovary and molecular pathways determining ovarian development are reviewed, focusing on mutations disrupting normal ovarian development. Disorders of sex development according to the revised nomenclature and classification in 46,XX individuals are summarized, including genetic progress in the field.

  11. Gas diffusion and temperature dependence of bubble nucleation during irradiation

    DEFF Research Database (Denmark)

    Foreman, A. J. E.; Singh, Bachu Narain

    1986-01-01

    The continuous production of gases at relatively high rates under fusion irradiation conditions may enhance the nucleation of cavities. This can cause dimensional changes and could induce embrittlement arising from gas accumulation on grain boundaries. Computer calculations have been made...... of the diatomic nucleation of helium bubbles, assuming helium to diffuse substitutionally, with radiation-enhanced diffusion at lower temperatures. The calculated temperature dependence of the bubble density shows excellent agreement with that observed in 600 MeV proton irradiations, including a reduction...... in activation energy below Tm/2. The coalescence of diatomic nuclei due to Brownian motion markedly improves the agreement and also provides a well-defined terminal density. Bubble nucleation by this mechanism is sufficiently fast to inhibit any appreciable initial loss of gas to grain boundaries during...

  12. Pipeline flow of heavy oil with temperature-dependent viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Maza Quinones, Danmer; Carvalho, Marcio da Silveira [Pontifical Catholic University of Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. of Mechanical Engineering], E-mail: msc@puc-rio.br

    2010-07-01

    The heavy oil produced offshore needs to be transported through pipelines between different facilities. The pipelines are usually laid down on the seabed and are submitted to low temperatures. Although heavy oils usually present Newtonian behavior, its viscosity is a strong function of temperature. Therefore, the prediction of pressure drops along the pipelines should include the solution of the energy equation and the dependence of viscosity to temperature. In this work, an asymptotic model is developed to study this problem. The flow is considered laminar and the viscosity varies exponentially with temperature. The model includes one-dimensional equations for the temperature and pressure distribution along the pipeline at a prescribed flow rate. The solution of the coupled differential equation is obtained by second-order finite difference. Results show a nonlinear behavior as a result of coupled interaction between the velocity, temperature, and temperature dependent material properties. (author)

  13. Temperature-dependent liquid metal flowrate control device

    International Nuclear Information System (INIS)

    Carlson, R.D.

    1978-01-01

    A temperature-dependent liquid metal flowrate control device includes a magnet and a ferromagnetic member defining therebetween a flow path for liquid metal, the ferromagnetic member being formed of a material having a curie temperature at which a change in the flow rate of the liquid metal is desired. According to the preferred embodiment the magnet is a cylindrical rod magnet axially disposed within a cylindrical member formed of a curie material and having iron pole pieces at the ends. A cylindrical iron shunt and a thin wall stainless steel barrier are disposed in the annulus between magnet and curie material. Below the curie temperature flow between steel barrier and curie material is impeded and above the curie temperature flow impedance is reduced

  14. Temperature dependent structural and vibrational properties of liquid indium

    Science.gov (United States)

    Patel, A. B.; Bhatt, N. K.

    2018-05-01

    The influence of the temperature effect on both the structure factor and the phonon dispersion relation of liquid indium have been investigated by means of pseudopotential theory. The Percus-Yevick Hard Sphere reference system is applied to describe the structural calculation. The effective electron-ion interaction is explained by using modified empty core potential due to Hasegawa et al. along with a local field correction function due to Ichimaru-Utsumi (IU). The temperature dependence of pair potential needed at higher temperatures was achieved by multiplying the damping factor exp(- π/kBT2k F r ) in the pair potential. Very close agreement of static structure factor, particularly, at elevated temperatures confirms the validity of the local potential. A positive dispersion is found in low-q region and the correct trend of phonon dispersion branches like the experimental; shows all broad features of collective excitations in liquid metals.

  15. Temperature-dependent chemical changes of metallic fuel

    Energy Technology Data Exchange (ETDEWEB)

    Youn, Young Sang; Lee, Jeong Mook; KimJong Hwan; Song, Hoon; Kim, Jong Yun [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    We observed the temperature-dependent variations of UZr alloy using surface analysis techniques such as X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscope (SEM) equipped with energy-dispersive Xray spectroscope (EDS). In this work, we exhibited the results of XPS, Raman, XRD, and SEM-EDS for U-10wt%Zr alloy at room temperature, 610 and 1130 .deg. C. In SEM-EDS data, we observed that uranium and zirconium elements uniformly exist. After the annealing of U-10Zr sample at 1130 .deg. C, the formation of zirconium carbide is verified through Raman spectroscopy and XRD results. Additionally, the change of valence state for uranium element is also confirmed by XPS analysis.

  16. Temperature-dependence of the QCD topological susceptibility

    Science.gov (United States)

    Kovacs, Tamas G.

    2018-03-01

    We recently obtained an estimate of the axion mass based on the hypothesis that axions make up most of the dark matter in the universe. A key ingredient for this calculation was the temperature-dependence of the topological susceptibility of full QCD. Here we summarize the calculation of the susceptibility in a range of temperatures from well below the finite temperature cross-over to around 2 GeV. The two main difficulties of the calculation are the unexpectedly slow convergence of the susceptibility to its continuum limit and the poor sampling of nonzero topological sectors at high temperature. We discuss how these problems can be solved by two new techniques, the first one with reweighting using the quark zero modes and the second one with the integration method.

  17. Temperature dependence of muonium reaction rates in the gas phase

    International Nuclear Information System (INIS)

    Fleming, D.G.; Garner, D.M.; Mikula, R.J.; British Columbia Univ., Vancouver

    1981-01-01

    A study of the temperature dependence of reaction rates has long been an important tool in establishing reaction pathways in chemical reactions. This is particularly true for the reactions of muonium (in comparison with those of hydrogen) since a measurement of the activation energy for chemical reaction is sensitive to both the height and the position of the potential barrier in the reaction plane. For collision controlled reactions, on the other hand, the reaction rate is expected to exhibit a weak T 1 sup(/) 2 dependence characteristic of the mean collision velocity. These concepts are discussed and their effects illustrated in a comparison of the chemical and spin exchange reaction rates of muonium and hydrogen in the temperature range approx.300-approx.500 K. (orig.)

  18. Heat experiment design to estimate temperature dependent thermal properties

    International Nuclear Information System (INIS)

    Romanovski, M

    2008-01-01

    Experimental conditions are studied to optimize transient experiments for estimating temperature dependent thermal conductivity and volumetric heat capacity. A mathematical model of a specimen is the one-dimensional heat equation with boundary conditions of the second kind. Thermal properties are assumed to vary nonlinearly with temperature. Experimental conditions refer to the thermal loading scheme, sampling times and sensor location. A numerical model of experimental configurations is studied to elicit the optimal conditions. The numerical solution of the design problem is formulated on a regularization scheme with a stabilizer minimization without a regularization parameter. An explicit design criterion is used to reveal the optimal sensor location, heating duration and flux magnitude. Results obtained indicate that even the strongly nonlinear experimental design problem admits the aggregation of its solution and has a strictly defined optimal measurement scheme. Additional region of temperature measurements with allowable identification error is revealed.

  19. Temperature-dependent particle-number projected moment of inertia

    International Nuclear Information System (INIS)

    Allal, N. H.; Fellah, M.; Benhamouda, N.; Oudih, M. R.

    2008-01-01

    Expressions of the parallel and perpendicular temperature-dependent particle-number projected nuclear moment of inertia have been established by means of a discrete projection method. They generalize that of the FTBCS method and are well adapted to numerical computation. The effects of particle-number fluctuations have been numerically studied for some even-even actinide nuclei by using the single-particle energies and eigenstates of a deformed Woods-Saxon mean field. It has been shown that the parallel moment of inertia is practically not modified by the use of the projection method. In contrast, the discrepancy between the projected and FTBCS perpendicular moment of inertia values may reach 5%. Moreover, the particle-number fluctuation effects vary not only as a function of the temperature but also as a function of the deformation for a given temperature. This is not the case for the system energy

  20. Temperature dependence of magnetoresistance in copper single crystals

    Science.gov (United States)

    Bian, Q.; Niewczas, M.

    2018-03-01

    Transverse magnetoresistance of copper single crystals has been measured in the orientation of open-orbit from 2 K to 20 K for fields up to 9 T. The experimental Kohler's plots display deviation between individual curves below 16 K and overlap in the range of 16 K-20 K. The violation of the Kohler's rule below 16 K indicates that the magnetotransport can not be described by the classical theory of electron transport on spherical Fermi surface with a single relaxation time. A theoretical model incorporating two energy bands, spherical and cylindrical, with different relaxation times has been developed to describe the magnetoresistance data. The calculations show that the electron-phonon scattering rates at belly and neck regions of the Fermi surface have different temperature dependencies, and in general, they do not follow T3 law. The ratio of the relaxation times in belly and neck regions decreases parabolically with temperature as A - CT2 , with A and C being constants.

  1. Temperature-dependent μ-Raman investigation of struvite crystals.

    Science.gov (United States)

    Prywer, Jolanta; Kasprowicz, D; Runka, T

    2016-04-05

    The effect of temperature on the vibrational properties of struvite crystals grown from silica gels was systematically studied by μ-Raman spectroscopy. The time-dependent Raman spectra recorded in the process of long time annealing of struvite crystal at 353 K do not indicate structural changes in the struvite crystal with the time of annealing. The temperature-dependent Raman spectra recorded in the range 298-423 K reveal a phase transition in struvite at about 368 K. Above this characteristic temperature, some of bands assigned to vibrations of the PO4 and NH4 tetrahedra and water molecules observed in the Raman spectra in low temperatures (orthorhombic phase) change their spectral parameters or disappear, which indicates a transition to a higher symmetry structure of struvite in the range of high temperatures. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Temperature Dependent Variations of Phonon Interactions in Nanocrystalline Cerium Oxide

    Directory of Open Access Journals (Sweden)

    Sugandha Dogra Pandey

    2015-01-01

    Full Text Available The temperature dependent anharmonic behavior of the phonon modes of nanocrystalline CeO2 was investigated in the temperature range of 80–440 K. The anharmonic constants have been derived from the shift in phonon modes fitted to account for the anharmonic contributions as well as the thermal expansion contribution using the high pressure parameters derived from our own high pressure experimental data reported previously. The total anharmonicity has also been estimated from the true anharmonicity as well as quasiharmonic component. In the line-width variation analysis, the cubic anharmonic term was found to dominate the quartic term. Finally, the phonon lifetime also reflected the trend so observed.

  3. Temperature Dependence of the Viscosity of Isotropic Liquids

    Science.gov (United States)

    Jadzyn, J.; Czechowski, G.; Lech, T.

    1999-04-01

    Temperature dependence of the shear viscosity measured for isotropic liquids belonging to the three homologous series: 4-(trans-4'-n-alkylcyclohexyl) isothiocyanatobenzenes (Cn H2n+1 CyHx Ph NCS; nCHBT, n=0-12), n-alkylcyanobiphenyls (CnH2n+1 Ph Ph CN; nCB, n=2-12) and 1,n-alkanediols (HO(CH2)nOH; 1,nAD, n=2-10) were analysed with the use of Arrhenius equation and its two modifications: Vogel--Fulcher and proposed in this paper. The extrapolation of the isothermal viscosity of 1,n-alkanediols (n=2-10) to n=1 leads to an interesting conclusion concerning the expected viscosity of methanediol, HOCH2OH, the compound strongly unstable in a pure state.

  4. Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex

    Directory of Open Access Journals (Sweden)

    Pilar Santolaria

    2016-01-01

    Full Text Available This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively. Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P < 0.001 although with important differences between bulls. A simultaneous evaluation of all the measured features by discriminant analysis revealed that nuclear area and average fluorescence intensity were the variables selected by stepwise discriminant function analysis as the best discriminators between SX and SY. In the second experiment, the sperm nuclear morphometric results from CASA-Morph in nonsexed (mixed SX and SY and sexed (SX semen samples from four bulls were compared. FISH allowed a successful classification of spermatozoa according to their sex chromosome content. X-sexed spermatozoa displayed a larger size and fluorescence intensity than nonsexed spermatozoa (P < 0.05. We conclude that the CASA-Morph fluorescence-based method has the potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

  5. Insect Sex Determination Manipulated by Their Endosymbionts: Incidences, Mechanisms and Implications.

    Science.gov (United States)

    Kageyama, Daisuke; Narita, Satoko; Watanabe, Masaya

    2012-02-10

    The sex-determining systems of arthropods are surprisingly diverse. Some species have male or female heterogametic sex chromosomes while other species do not have sex chromosomes. Most species are diploids but some species, including wasps, ants, thrips and mites, are haplodiploids (n in males; 2n in females). Many of the sexual aberrations, such as sexual mosaics, sex-specific lethality and conversion of sexuality, can be explained by developmental defects including double fertilization of a binucleate egg, loss of a sex chromosome or perturbation of sex-determining gene expression, which occur accidentally or are induced by certain environmental conditions. However, recent studies have revealed that such sexual aberrations can be caused by various groups of vertically-transmitted endosymbiotic microbes such as bacteria of the genera Wolbachia, Rickettsia, Arsenophonus, Spiroplasma and Cardinium, as well as microsporidian protists. In this review, we first summarize the accumulated data on endosymbiont-induced sexual aberrations, and then discuss how such endosymbionts affect the developmental system of their hosts and what kinds of ecological and evolutionary effects these endosymbionts have on their host populations.

  6. Sex determination from scapular length measurements by CT scans images in a Caucasian population.

    Science.gov (United States)

    Giurazza, F; Schena, E; Del Vescovo, R; Cazzato, R L; Mortato, L; Saccomandi, P; Paternostro, F; Onofri, L; Zobel, B Beomonte

    2013-01-01

    Together with race, stature and age, sex is a main component of the biological identity. Thanks to its proportional correlation with parts of the human body, sex can be evaluated form the skeleton. The most accurate approach to determine sex by bone size is based on os coxae or skull. After natural disaster their presence can never be guaranteed, therefore the development of methods of sex determination using other skeletal elements can result crucial. Herein, sexual dimorphism in the human scapula is used to develop a two-variable discriminant function for sex estimation. We have enrolled 100 males and 100 females who underwent thoracic CT scan evaluation and we have estimated two scapular diameters. The estimation has been carried out by analyzing images of the scapulae of each patient after three dimensional post-processing reconstructions. The two-variable function allows to obtain an overall accuracy of 88% on the calibration sample. Furthermore, we have employed the mentioned function on a collection of 10 individual test sample from the collection of the "Museo di Anatomia Umana di Firenze" of the Università degli Studi di Firenze; sex has been correctly predicted on 9 skeletons.

  7. Temperature dependence of the electronic structure of semiconductors and insulators

    Energy Technology Data Exchange (ETDEWEB)

    Poncé, S., E-mail: samuel.pon@gmail.com; Gillet, Y.; Laflamme Janssen, J.; Gonze, X. [European Theoretical Spectroscopy Facility and Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, bte L07.03.01, B-1348 Louvain-la-neuve (Belgium); Marini, A. [Consiglio Nazionale delle Ricerche (CNR), Via Salaria Km 29.3, CP 10, 00016 Monterotondo Stazione (Italy); Verstraete, M. [European Theoretical Spectroscopy Facility and Physique des matériaux et nanostructures, Université de Liège, Allée du 6 Août 17, B-4000 Liège (Belgium)

    2015-09-14

    The renormalization of electronic eigenenergies due to electron-phonon coupling (temperature dependence and zero-point motion effect) is sizable in many materials with light atoms. This effect, often neglected in ab initio calculations, can be computed using the perturbation-based Allen-Heine-Cardona theory in the adiabatic or non-adiabatic harmonic approximation. After a short description of the recent progresses in this field and a brief overview of the theory, we focus on the issue of phonon wavevector sampling convergence, until now poorly understood. Indeed, the renormalization is obtained numerically through a slowly converging q-point integration. For non-zero Born effective charges, we show that a divergence appears in the electron-phonon matrix elements at q → Γ, leading to a divergence of the adiabatic renormalization at band extrema. This problem is exacerbated by the slow convergence of Born effective charges with electronic wavevector sampling, which leaves residual Born effective charges in ab initio calculations on materials that are physically devoid of such charges. Here, we propose a solution that improves this convergence. However, for materials where Born effective charges are physically non-zero, the divergence of the renormalization indicates a breakdown of the adiabatic harmonic approximation, which we assess here by switching to the non-adiabatic harmonic approximation. Also, we study the convergence behavior of the renormalization and develop reliable extrapolation schemes to obtain the converged results. Finally, the adiabatic and non-adiabatic theories, with corrections for the slow Born effective charge convergence problem (and the associated divergence) are applied to the study of five semiconductors and insulators: α-AlN, β-AlN, BN, diamond, and silicon. For these five materials, we present the zero-point renormalization, temperature dependence, phonon-induced lifetime broadening, and the renormalized electronic band structure.

  8. Possibility of Morphometrical Determining of Sex of Steppe Eagle Nestlings from Western and Eastern Populations?

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2018-03-01

    Full Text Available Sexual dimorphism among nestlings of the Steppe Eagle (Aquila nipalensis is poorly manifested. Thus, determining of sex by morphometric methods encountered many difficulties and could be completed only by the most experienced ornithologists who knows the species very well. This article presents a morphometric method for determining sex of nestlings of the Steppe Eagles from different breeding populations that belongs to different size classes. The method is based on classification formula obtained via linear discriminant analysis conducted for the data set of measurements of Steppe Eagle’s nestlings from Central Kazakhstan and Altai Republic in 2017. To control the sex determination of nestlings a molecular-genetics method was used.

  9. Temperature dependence of third order ion molecule reactions. The reaction H+3 + 2H2 = H+5 + H2

    International Nuclear Information System (INIS)

    Hiraoka, K.; Kebarle, P.

    1975-01-01

    The rate constants k 1 for Reaction (1): H + 3 +2H 2 = H + 5 +H 2 were measured in the temperature range 100--300 degreeK. The temperature dependence of k 1 has the form k 1 proportionalT - /subn/, where n=2.3. Pierce and Porter have reported a much stronger negative temperature dependence with n=4.6. The difference arises from a determination of k 1 at 300 degreeK obtained by Arifov and used by Porter. The present k 1 (300 degreeK) =9times10 -30 (cm 6 molecules -2 center-dotsec -1 ). This is more than an order of magnitude larger than the Arifov value. The temperature dependence of third body dependent association reactions like (1) is examined on the basis of the energy transfer theory and the recently proposed trimolecular complex transition state theory by Meot-Ner, Solomon, Field, and Gershinowitz. The temperature dependence of the rate constant for the reverse reaction (-1) is obtained from k 1 and the previously determined temperature dependence of the equilibria (1). k/sub -//sub 1/ gives a good straight line Arrhenius plot leading to k/sub -//sub 1/ =8.7times10 -6 exp(-8.4/RT) cm 3 molecules -1 center-dotsec -1 . The activation energy is in kcal/mole. The preexponential factor is much larger than the rate constant for Langevin collisions. This is typical for pyrolysis of ions involving second order activation

  10. Temperature dependence of exchange bias in (NiFe/IrMn)n multilayer films studied through static and dynamic techniques

    Science.gov (United States)

    Adams, Daniel J.; Khanal, Shankar; Khan, Mohammad Asif; Maksymov, Artur; Spinu, Leonard

    2018-05-01

    The in-plane temperature dependence of exchange bias was studied through both dc magnetometry and ferromagnetic resonance spectroscopy in a series of [NiFe/IrMn]n multilayer films, where n is the number of layer repetitions. Major hysteresis loops were recorded in the temperature range of 300 K to 2 K to reveal the effect of temperature on the exchange bias in the static regime while temperature-dependent continuous-wave ferromagnetic resonance for frequencies from 3 to 16 GHz was used to determine the exchange bias dynamically. Strong divergence between the values of exchange bias determined using the two different types of measurements as well as a peak in temperature dependence of the resonance linewidth were observed. These results are explained in terms of the slow-relaxer mechanism.

  11. Methyl farnesoate synthesis is necessary for the environmental sex determination in the water flea Daphnia pulex.

    Science.gov (United States)

    Toyota, Kenji; Miyakawa, Hitoshi; Hiruta, Chizue; Furuta, Kenjiro; Ogino, Yukiko; Shinoda, Tetsuro; Tatarazako, Norihisa; Miyagawa, Shinichi; Shaw, Joseph R; Iguchi, Taisen

    2015-09-01

    Sex-determination systems can be divided into two groups: genotypic sex determination (GSD) and environmental sex determination (ESD). ESD is an adaptive life-history strategy that allows control of sex in response to environmental cues in order to optimize fitness. However, the molecular basis of ESD remains largely unknown. The micro crustacean Daphnia pulex exhibits ESD in response to various external stimuli. Although methyl farnesoate (MF: putative juvenile hormone, JH, in daphnids) has been reported to induce male production in daphnids, the role of MF as a sex-determining factor remains elusive due to the lack of a suitable model system for its study. Here, we establish such a system for ESD studies in D. pulex. The WTN6 strain switches from producing females to producing males in response to the shortened day condition, while the MFP strain only produces females, irrespective of day-length. To clarify whether MF has a novel physiological role as a sex-determining factor in D. pulex, we demonstrate that a MF/JH biosynthesis inhibitor suppressed male production in WTN6 strain reared under the male-inducible condition, shortened day-length. Moreover, we show that juvenile hormone acid O-methyltransferase (JHAMT), a critical enzyme of MF/JH biosynthesis, displays MF-generating activity by catalyzing farnesoic acid. Expression of the JHAMT gene increased significantly just before the MF-sensitive period for male production in the WTN6 strain, but not in the MFP strain, when maintained under male-inducible conditions. These results suggest that MF synthesis regulated by JHAMT is necessary for male offspring production in D. pulex. Our findings provide novel insights into the genetic underpinnings of ESD and they begin to shed light on the physiological function of MF as a male-fate determiner in D. pulex. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Prenatal sex determination by radioimmunoassay of testosterone with and without chromatography of the amniotic fluid

    International Nuclear Information System (INIS)

    Distler, W.; Boniver-Ollmann, U.; Tigges, J.; Terinde, R.; Claussen, U.

    1979-01-01

    Amniotic fluid testosterone measured by radioimmunoassay (RIA) without chromatography (immunoreactive testosterone) seems not to be a definitive test for prenatal sex determination in all cases. In this study testosterone (T) levels measured by RIA with chromatography of the amniotic fluid samples were compared with immunoreactive testosterone (iT) values, to determine the predictive accuracy of the two methods. In 111 amniotic fluid samples between 15 and 19 weeks of gestation iT and T were measured parallelly. There are significant differences between iT- and T-means of both sexes (p [de

  13. Multilocus Sex Determination Revealed in Two Populations of Gynodioecious Wild Strawberry, Fragaria vesca subsp. bracteata.

    Science.gov (United States)

    Ashman, Tia-Lynn; Tennessen, Jacob A; Dalton, Rebecca M; Govindarajulu, Rajanikanth; Koski, Matthew H; Liston, Aaron

    2015-10-19

    Gynodioecy, the coexistence of females and hermaphrodites, occurs in 20% of angiosperm families and often enables transitions between hermaphroditism and dioecy. Clarifying mechanisms of sex determination in gynodioecious species can thus illuminate sexual system evolution. Genetic determination of gynodioecy, however, can be complex and is not fully characterized in any wild species. We used targeted sequence capture to genetically map a novel nuclear contributor to male sterility in a self-pollinated hermaphrodite of Fragaria vesca subsp. bracteata from the southern portion of its range. To understand its interaction with another identified locus and possibly additional loci, we performed crosses within and between two populations separated by 2000 km, phenotyped the progeny and sequenced candidate markers at both sex-determining loci. The newly mapped locus contains a high density of pentatricopeptide repeat genes, a class commonly involved in restoration of fertility caused by cytoplasmic male sterility. Examination of all crosses revealed three unlinked epistatically interacting loci that determine sexual phenotype and vary in frequency between populations. Fragaria vesca subsp. bracteata represents the first wild gynodioecious species with genomic evidence of both cytoplasmic and nuclear genes in sex determination. We propose a model for the interactions between these loci and new hypotheses for the evolution of sex determining chromosomes in the subdioecious and dioecious Fragaria. Copyright © 2015 Ashman et al.

  14. Formal and informal sex education as determinants of premarital sexual behavior.

    Science.gov (United States)

    Spanier, G B

    1976-01-01

    Controversies exist regarding the effects of sex education in the schools and informal sex education obtained from parents, peers, the mass media, and other sources. Similarly, there is widespread interest in premarital sexual behavior, especially its determinants. This study presents several issues reflecting these concerns which have been the subject of much speculation but which have received little attention by researchers. The purpose of this study was to investigate--through the use of respondent reports--how formal and informal sex education influences premarital sexual behavior during college. A national probability sample of 1177 college students was studied using face-to-face interviews with approximately equal numbers of males and females. These interviews, which were conducted for the Institute for Sex Research, included questions about past and present sexual involvement and other attitudinal, behavioral and background variables. Accordingly, the data about sexual behavior and attitudes are based on the interviewees' self-reports. Indices were created which operationalized independent variables such as familial sexual conservatism, exposure to eroticism, perceived sex knowledge, and sexual exposure and assault during childhood and adolescence. Individual items reflecting childhood sex play, masturbation, current religiosity, religiosity while growing up, social class, sources of sex information, sex education in classrooms, and high school and college dating were used. The dependent variable, premarital sociosexual involvement, is a composite measure of incidence and prevalence of premarital heterosexual involvement which meets Guttman scaling criteria. An Automatic Interaction Detector analysis was used to determine the relative influences of reported sexualization variables on premarital sexual behavior. Major findings can be summarized as follows: Heterosexual behavior progresses in stepwise fashion from elementary to advanced levels of involvement

  15. Tribolium castaneum Transformer-2 regulates sex determination and development in both males and females.

    Science.gov (United States)

    Shukla, Jayendra Nath; Palli, Subba Reddy

    2013-12-01

    Tribolium castaneum Transformer (TcTra) is essential for female sex determination and maintenance through the regulation of sex-specific splicing of doublesex (dsx) pre-mRNA. In females, TcTra also regulates the sex-specific splicing of its own pre-mRNA to ensure continuous production of functional Tra protein. Transformer protein is absent in males and hence dsx pre-mRNA is spliced in a default mode. The mechanisms by which males inhibit the production of functional Tra protein are not known. Here, we report on functional characterization of transformer-2 (tra-2) gene (an ortholog of Drosophila transformer-2) in T. castaneum. RNA interference-mediated knockdown in the expression of gene coding for tra-2 in female pupae or adults resulted in the production of male-specific isoform of dsx and both female and male isoforms of tra suggesting that Tra-2 is essential for the female-specific splicing of tra and dsx pre-mRNAs. Interestingly, knockdown of tra-2 in males did not affect the splicing of dsx but resulted in the production of both female and male isoforms of tra suggesting that Tra-2 suppresses female-specific splicing of tra pre-mRNA in males. This dual regulation of sex-specific splicing of tra pre-mRNA ensures a tight regulation of sex determination and maintenance. These data suggest a critical role for Tra-2 in suppression of female sex determination cascade in males. In addition, RNAi studies showed that Tra-2 is also required for successful embryonic and larval development in both sexes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Sex determination of Pohnpei Micronesian kingfishers using morphological and molecular genetic techniques

    Science.gov (United States)

    Kesler, Dylan C.; Lopes, I.F.; Haig, Susan M.

    2006-01-01

    Conservation-oriented studies of Micronesian Kingfishers (Todiramphus cinnamominus) have been hindered by a lack of basic natural history information, despite the status of the Guam subspecies (T. c. cinnamominus) as one of the most endangered species in the world. We used tissue samples and morphometric measures from museum specimens and wild-captured Pohnpei Micronesian Kingfishers (T. c. reichenbachii) to develop methods for sex determination. We present a modified molecular protocol and a discriminant function that yields the probability that a particular individual is male or female. Our results revealed that females were significantly larger than males, and the discriminant function correctly predicted sex in 73% (30/41) of the individuals. The sex of 86% (18/21) of individuals was correctly assigned when a moderate reliability threshold was set. Sex determination using molecular genetic techniques was more reliable than methods based on morphology. Our results will facilitate recovery efforts for the critically endangered Guam Micronesian Kingfisher and provide a basis for sex determination in the 11 other endangered congeners in the Pacific Basin.

  17. The evolution of environmental and genetic sex determination in fluctuating environments.

    Science.gov (United States)

    Van Dooren, Tom J M; Leimar, Olof

    2003-12-01

    Twenty years ago, Bulmer and Bull suggested that disruptive selection, produced by environmental fluctuations, can result in an evolutionary transition from environmental sex determination (ESD) to genetic sex determination (GSD). We investigated the feasibility of such a process, using mutation-limited adaptive dynamics and individual-based computer simulations. Our model describes the evolution of a reaction norm for sex determination in a metapopulation setting with partial migration and variation in an environmental variable both within and between local patches. The reaction norm represents the probability of becoming a female as a function of environmental state and was modeled as a sigmoid function with two parameters, one giving the location (i.e., the value of the environmental variable for which an individual has equal chance of becoming either sex) and the other giving the slope of the reaction norm for that environment. The slope can be interpreted as being set by the level of developmental noise in morph determination, with less noise giving a steeper slope and a more switchlike reaction norm. We found convergence stable reaction norms with intermediate to large amounts of developmental noise for conditions characterized by low migration rates, small differential competitive advantages between the sexes over environments, and little variation between individual environments within patches compared to variation between patches. We also considered reaction norms with the slope parameter constrained to a high value, corresponding to little developmental noise. For these we found evolutionary branching in the location parameter and a transition from ESD toward GSD, analogous to the original analysis by Bulmer and Bull. Further evolutionary change, including dominance evolution, produced a polymorphism acting as a GSD system with heterogamety. Our results point to the role of developmental noise in the evolution of sex determination.

  18. Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex.

    Science.gov (United States)

    Santolaria, Pilar; Pauciullo, Alfredo; Silvestre, Miguel A; Vicente-Fiel, Sandra; Villanova, Leyre; Pinton, Alain; Viruel, Juan; Sales, Ester; Yániz, Jesús L

    2016-01-01

    This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph) with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively). Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

  19. Applying iPSCs for Preserving Endangered Species and Elucidating the Evolution of Mammalian Sex Determination.

    Science.gov (United States)

    Honda, Arata

    2018-04-06

    The endangered species Tokudaia osimensis has the unique chromosome constitution of 2n = 25, with an XO/XO sex chromosome configuration (2n = 25; XO). There is urgency to preserve this species and to elucidate the regulator(s) that can discriminate the males and females arising from the indistinguishable sex chromosome constitution. However, it is not realistic to examine this rare animal species by sacrificing individuals. Recently, true naïve induced pluripotent stem cells were successfully generated from a female T. osimensis, and the sexual plasticity of its germ cells was elucidated. This achievement constitutes the basis of an attractive research area, including embryonic fate determination, sex determination, and factor(s) that can replace the Y chromosome. In this essay, concrete strategies to conserve rare animal species and to reveal their specific characteristics using other compatible and abundant animals are proposed. © 2018 WILEY Periodicals, Inc.

  20. Determination of Sperm Sex Ratio in Bovine Semen Using Multiplex Real-time Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Trisadee Khamlor

    2014-10-01

    Full Text Available Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP gene and sex-determining region Y (SRY were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99% comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05. The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90% as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.

  1. The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

    Science.gov (United States)

    Rideout, Elizabeth J; Narsaiya, Marcus S; Grewal, Savraj S

    2015-12-01

    Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

  2. The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

    Directory of Open Access Journals (Sweden)

    Elizabeth J Rideout

    2015-12-01

    Full Text Available Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

  3. Temperature dependence of the fracture toughness and the cleavage fracture strength of a pressure vessel steel

    International Nuclear Information System (INIS)

    Kotilainen, H.

    1980-01-01

    A new model for the temperature dependence of the fracture toughness has been sought. It is based on the yielding processes at the crack tip, which are thought to be competitive with fracture. Using this method a good correlation between measured and calculated values of fracture toughness has been found for a Cr-Mo-V pressure vessel steel as well as for A533B. It has been thought that the application of this method can reduce the number of surveillance specimens in nuclear reactors. A method for the determination of the cleavage fracture strength has been proposed. 28 refs

  4. Suppressing gravitino thermal production with a temperature-dependent messenger coupling

    International Nuclear Information System (INIS)

    Badziak, Marcin; Dalianis, Ioannis; Lalak, Zygmunt

    2016-01-01

    We show that the constraints on GMSB theories from the gravitino cosmology can be significantly relaxed if the messenger-spurion coupling is temperature dependent. We demonstrate this novel mechanism in a scenario in which this coupling depends on the VEV of an extra singlet field S that interacts with the thermalized plasma which can result in a significantly suppressed gravitino production rate. In such a scenario the relic gravitino abundance is determined by the thermal dynamics of the S field and it is easy to fit the observed dark matter abundance evading the stringent constraints on the reheating temperature, thus making gravitino dark matter consistent with thermal leptogenesis.

  5. Label-free detection of sex determining region Y (SRY) via capacitive biosensor

    KAUST Repository

    Sivashankar, Shilpa; Sapsanis, Christos; Agambayev, Sumeyra; Buttner, Ulrich; Salama, Khaled N.

    2016-01-01

    In this work, we present for the first time, the use of a simple fractal capacitive biosensor for the quantification and detection of sex-determining region Y (SRY) genes. This section of genetic code, which is found on the Y chromosome, finds

  6. Observation of a ZZW female in a natural population: implications for avian sex determination.

    Science.gov (United States)

    Arit, D; Bensch, S; Hansson, B; Hasselquist, D; Westerdahl, H

    2004-01-01

    Avian sex determination is chromosomal; however, the underlying mechanisms are not yet understood. There is no conclusive evidence for either of two proposed mechanisms: a dominant genetic switch or a dosage mechanism. No dominant sex-determining gene on the female-specific W chromosome has been found. Birds lack inactivation of one of the Z chromosomes in males, but seem to compensate for a double dose of Z-linked genes by other mechanisms. Recent studies showing female-specific expression of two genes may support an active role of the W chromosome. To resolve the question of avian sex determination the investigation of birds with a 2A: ZZW or 2A: ZO genotype would be decisive. Here, we report the case of an apparent 2A: ZZW great reed warbler (Acrocephalus arundinaceus) female breeding in a natural population, which was detected using Z-linked microsatellites. Our data strongly suggest a role of W-linked genes in avian sex determination. PMID:15252998

  7. Determinants of Human Papillomavirus Vaccination Intention Among Female Sex Workers in Amsterdam, the Netherlands

    NARCIS (Netherlands)

    Marra, E.; Dam, L. van; Kroone, N.; Alberts, C.J.; Craanen, M.; Zimet, G.D.; Heijmam, T.; Hogewoning, A.A.; Sonder, G.J.B.; Vries, H.J.C. de; Alberts, C.J.; Paulussen, T.G.W.M.; Schim van der Loeff, M.F.

    2017-01-01

    Introduction: Female sex workers (FSWs) are at risk for human papillomavirus (HPV)-induced diseases but are currently not targeted by the HPV vaccination program in the Netherlands. We explored determinants of their intention to get vaccinated against HPV in case vaccination would be offered to

  8. What was the ancestral sex-determining mechanism in amniote vertebrates?

    Czech Academy of Sciences Publication Activity Database

    Johnson Pokorná, Martina; Kratochvíl, L.

    2016-01-01

    Roč. 91, č. 1 (2016), s. 1-12 ISSN 1464-7931 R&D Projects: GA ČR GAP506/10/0718 Institutional support: RVO:67985904 Keywords : environmental sex determination * phylogeny * polyphenism Subject RIV: EG - Zoology Impact factor: 11.615, year: 2016

  9. Temperature dependent transport characteristics of graphene/n-Si diodes

    International Nuclear Information System (INIS)

    Parui, S.; Ruiter, R.; Zomer, P. J.; Wojtaszek, M.; Wees, B. J. van; Banerjee, T.

    2014-01-01

    Realizing an optimal Schottky interface of graphene on Si is challenging, as the electrical transport strongly depends on the graphene quality and the fabrication processes. Such interfaces are of increasing research interest for integration in diverse electronic devices as they are thermally and chemically stable in all environments, unlike standard metal/semiconductor interfaces. We fabricate such interfaces with n-type Si at ambient conditions and find their electrical characteristics to be highly rectifying, with minimal reverse leakage current (<10 −10  A) and rectification of more than 10 6 . We extract Schottky barrier height of 0.69 eV for the exfoliated graphene and 0.83 eV for the CVD graphene devices at room temperature. The temperature dependent electrical characteristics suggest the influence of inhomogeneities at the graphene/n-Si interface. A quantitative analysis of the inhomogeneity in Schottky barrier heights is presented using the potential fluctuation model proposed by Werner and Güttler

  10. Temperature dependence of the two photon absorption in indium arsenide

    International Nuclear Information System (INIS)

    Berryman, K.W.; Rella, C.W.

    1995-01-01

    Nonlinear optical processes in semiconductors have long been a source of interesting physics. Two photon absorption (TPA) is one such process, in which two photons provide the energy for the creation of an electron-hole pair. Researchers at other FEL centers have studied room temperature TPA in InSb, InAs, and HgCdTe. Working at the Stanford Picosecond FEL Center, we have extended and refined this work by measuring the temperature dependence of the TPA coefficient in InAs over the range from 80 to 350 K at four wavelengths: 4.5, 5.06, 6.01, and 6.3 microns. The measurements validate the functional dependence of recent band structure calculations with enough precision to discriminate parabolic from non-parabolic models, and to begin to observe smaller effects, such as contributions due to the split-off band. These experiments therefore serve as a strong independent test of the Kane band theory, as well as providing a starting point for detailed observations of other nonlinear absorption mechanisms

  11. Temperature dependence of thermal pressure for NaCl

    Science.gov (United States)

    Singh, Chandra K.; Pande, Brijesh K.; Pandey, Anjani K.

    2018-05-01

    Engineering applications of the materials can be explored upto the desired limit of accuracy with the better knowledge of its mechanical and thermal properties such as ductility, brittleness and Thermal Pressure. For the resistance to fracture (K) and plastic deformation (G) the ratio K/G is treated as an indication of ductile or brittle character of solids. In the present work we have tested the condition of ductility and brittleness with the calculated values of K/G for the NaCl. It is concluded that the nature of NaCl can be predicted upto high temperature simply with the knowledge of its elastic stiffness constant only. Thermoelastic properties of materials at high temperature is directly related to thermal pressure and volume expansion of the materials. An expression for the temperature dependence of thermal pressure is formulated using basic thermodynamic identities. It is observed that thermal pressure ΔPth calculated for NaCl by using Kushwah formulation is in good agreement with the experimental values also the thermal pressure increases with the increase in temperature.

  12. Temperature-dependent binding of cyclosporine to an erythrocyte protein

    International Nuclear Information System (INIS)

    Agarwal, R.P.; Threatte, G.A.; McPherson, R.A.

    1987-01-01

    In this competitive binding assay to measure endogenous binding capacity for cyclosporine (CsA) in erythrocyte lysates, a fixed amount of [ 3 H]CsA plus various concentrations of unlabeled CsA is incubated with aliquots of a test hemolysate. Free CsA is then adsorbed onto charcoal and removed by centrifugation; CsA complexed with a cyclosporine-binding protein (CsBP) remains in the supernate. We confirmed the validity of this charcoal-separation mode of binding analysis by comparison with equilibrium dialysis. Scatchard plot analysis of the results at 4 degrees C yielded a straight line with slope corresponding to a binding constant of 1.9 X 10(7) L/mol and a saturation capacity of approximately 4 mumol per liter of packed erythrocytes. Similar analysis of binding data at 24 degrees C and 37 degrees C showed that the binding constant decreased with increasing temperature, but the saturation capacity did not change. CsBP was not membrane bound but appeared to be freely distributed within erythrocytes. 125 I-labeled CsA did not complex with the erythrocyte CsBP. Several antibiotics and other drugs did not inhibit binding between CsA and CsBP. These findings may explain the temperature-dependent uptake of CsA by erythrocytes in whole blood and suggest that measurement of CsBP in erythrocytes or lymphocytes may help predict therapeutic response or toxicity after administration of CsA

  13. Temperature dependence of single-particle properties in nuclear matter

    International Nuclear Information System (INIS)

    Zuo, W.; Lu, G.C.; Li, Z.H.; Lombardo, U.; Schulze, H.-J.

    2006-01-01

    The single-nucleon potential in hot nuclear matter is investigated in the framework of the Brueckner theory by adopting the realistic Argonne V 18 or Nijmegen 93 two-body nucleon-nucleon interaction supplemented by a microscopic three-body force. The rearrangement contribution to the single-particle potential induced by the ground state correlations is calculated in terms of the hole-line expansion of the mass operator and provides a significant repulsive contribution in the low-momentum region around and below the Fermi surface. Increasing temperature leads to a reduction of the effect, while increasing density makes it become stronger. The three-body force suppresses somewhat the ground state correlations due to its strong short-range repulsion, increasing with density. Inclusion of the three-body force contribution results in a quite different temperature dependence of the single-particle potential at high enough densities as compared to that adopting the pure two-body force. The effects of three-body force and ground state correlations on the nucleon effective mass are also discussed

  14. Temperature dependent quasiparticle renormalization in nickel and iron

    Energy Technology Data Exchange (ETDEWEB)

    Ovsyannikov, Ruslan; Thirupathaiah, Setti; Sanchez-Barriga, Jaime; Fink, Joerg; Duerr, Hermann [Helmholtz Zentrum Berlin, BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany)

    2010-07-01

    One of the fundamental consequences of electron correlation effects is that the bare particles in solids become 'dressed' with an excitation cloud resulting in quasiparticles. Such a quasiparticle will carry the same spin and charge as the original particle, but will have a renormalized mass and a finite lifetime. The properties of many-body interactions are described with a complex function called self energy which is directly accessible to modern high-resolution angle resolved photoemission spectroscopy (ARPES). Ferromagnetic metals like nickel or iron offers the exciting possibility to study the spin dependence of quasiparticle coupling to bosonic modes. Utilizing the exchange split band structure as an intrinsic 'spin detector' it is possible to distinguish between electron-phonon and electron-magnon coupling phenomena. In this contribution we will report a systematic investigation of the k- and temperature dependence of the electron-boson coupling in nickel and iron metals as well as discuss origin of earlier observed anomalous lifetime broadening of majority spin states of nickel at Fermi level.

  15. Temperature dependence of work hardening in sparsely twinning zirconium

    International Nuclear Information System (INIS)

    Singh, Jaiveer; Mahesh, S.; Roy, Shomic; Kumar, Gulshan; Srivastava, D.; Dey, G.K.; Saibaba, N.; Samajdar, I.

    2017-01-01

    Fully recrystallized commercial Zirconium plates were subjected to uniaxial tension. Tests were conducted at different temperatures (123 K - 623 K) and along two plate directions. Both directions were nominally unfavorable for deformation twinning. The effect of the working temperature on crystallographic texture and in-grain misorientation development was insignificant. However, systematic variation in work hardening and in the area fraction and morphology of deformation twins was observed with temperature. At all temperatures, twinning was associated with significant near boundary mesoscopic shear, suggesting a possible linkage with twin nucleation. A binary tree based model of the polycrystal, which explicitly accounts for grain boundary accommodation and implements the phenomenological extended Voce hardening law, was implemented. This model could capture the measured stress-strain response and twin volume fractions accurately. Interestingly, slip and twin system hardness evolution permitted multiplicative decomposition into temperature-dependent, and accumulated strain-dependent parts. Furthermore, under conditions of relatively limited deformation twinning, the work hardening of the slip and twin systems followed two phenomenological laws proposed in the literature for non-twinning single-phase face centered cubic materials.

  16. Modeling temperature dependent singlet exciton dynamics in multilayered organic nanofibers

    Science.gov (United States)

    de Sousa, Leonardo Evaristo; de Oliveira Neto, Pedro Henrique; Kjelstrup-Hansen, Jakob; da Silva Filho, Demétrio Antônio

    2018-05-01

    Organic nanofibers have shown potential for application in optoelectronic devices because of the tunability of their optical properties. These properties are influenced by the electronic structure of the molecules that compose the nanofibers and also by the behavior of the excitons generated in the material. Exciton diffusion by means of Förster resonance energy transfer is responsible, for instance, for the change with temperature of colors in the light emitted by systems composed of different types of nanofibers. To study in detail this mechanism, we model temperature dependent singlet exciton dynamics in multilayered organic nanofibers. By simulating absorption and emission spectra, the possible Förster transitions are identified. Then, a kinetic Monte Carlo model is employed in combination with a genetic algorithm to theoretically reproduce time-resolved photoluminescence measurements for several temperatures. This procedure allows for the obtainment of different information regarding exciton diffusion in such a system, including temperature effects on the Förster transfer efficiency and the activation energy of the Förster mechanism. The method is general and may be employed for different systems where exciton diffusion plays a role.

  17. A model for temperature dependent resistivity of metallic superlattices

    Directory of Open Access Journals (Sweden)

    J. I. Uba

    2015-11-01

    Full Text Available The temperature dependent resistivity of metallic superlattices, to first order approximation, is assumed to have same form as bulk metal, ρ(T = ρo + aT, which permits describing these structures as linear atomic chain. The assumption is, substantiated with the derivation of the above expression from the standard magnetoresistance equation, in which the second term, a Bragg scattering factor, is a correction to the usual model involving magnon and phonon scatterings. Fitting the model to Fe/Cr data from literature shows that Bragg scattering is dominant at T < 50 K and magnon and phonon coefficients are independent of experiment conditions, with typical values of 4.7 × 10−4 μΩcmK−2 and −8 ± 0.7 × 10−7μΩcmK−3. From the linear atomic chain model, the dielectric constant ε q , ω = 8 . 33 × 10 − 2 at Debye frequency for all materials and acoustic speed and Thomas – Fermi screening length are pressure dependent with typical values of 1.53 × 104 m/s and 1.80 × 109 m at 0.5 GPa pressure for an Fe/Cr structure.

  18. Temperature-Dependent Dielectric Properties of Al/Epoxy Nanocomposites

    Science.gov (United States)

    Wang, Zijun; Zhou, Wenying; Sui, Xuezhen; Dong, Lina; Cai, Huiwu; Zuo, Jing; Chen, Qingguo

    2016-06-01

    Broadband dielectric spectroscopy was carried out to study the transition in electrical properties of Al/epoxy nanocomposites over the frequency range of 1-107 Hz and the temperature range of -20°C to 200°C. The dielectric permittivity, dissipation factor, and electrical conductivity of the nanocomposites increased with temperature and showed an abrupt increase around the glass transition temperature ( T g). The results clearly reveal an interesting transition of the electrical properties with increasing temperature: insulator below 70°C, conductor at about 70°C. The behavior of the transition in electrical properties of the nanocomposites was explored at different temperatures. The presence of relaxation peaks in the loss tangent and electric modulus spectra of the nanocomposites confirms that the chain segmental dynamics of the polymer is accompanied by the absorption of energy given to the system. It is suggested that the temperature-dependent transition of the electric properties in the nanocomposite is closely associated with the α-relaxation. The large increase in the dissipation factor and electric conductivity depends on the direct current conduction of thermally activated charge carriers resulting from the epoxy matrix above T g.

  19. Temperature dependence of heat sensitization and thermotolerance induction with ethanol

    International Nuclear Information System (INIS)

    Henle, K.J.; Nagle, W.A.; Moss, A.J.

    1987-01-01

    Cytoxicity of 1 M ethanol was strongly temperature dependent; survival curves between 34 0 and 39 0 C were similar to heat survival curves between 40 and 45 0 without ethanol. Ethanol was non-toxic at 22 0 ; at 34.5 0 and 35.5 0 ethanol survival curves were biphasic. The major effect of 1 M ethanol was an effective temperature shift of 6.4 Celsius degrees, although temperatures between 34 0 and 36 0 caused additional sensitization reminiscent of the stepdown heating phenomenon. Induction of thermotolerance with equitoxic ethanol exposures at 35.5 0 and 37 0 or with heat alone (10 min, 45 0 ) resulted in tolerance development with similar kinetics; in contrast, ethanol exposures at 22 0 did not induce any tolerance development with similar kinetics; in contrast, ethanol exposures at 22 0 did not induce any tolerance to hyperthermia. These data provide a rationale for conflicting reports in the literature regarding thermotolerance induction by ethanol and suggest that ethanol causes ''heat'' stress at temperatures that are generally considered to be physiological. This interpretation predicts that the use of ethanol and other organic solvents in high concentrations will cause effects at 37 0 that normally occur only at hyperthermic temperatures, including membrane perturbations and HSP synthesis, and that ''physiological'' temperatures must be precisely controlled under those conditions

  20. Temperature Dependence of Interband Transitions in Wurtzite InP Nanowires.

    Science.gov (United States)

    Zilli, Attilio; De Luca, Marta; Tedeschi, Davide; Fonseka, H Aruni; Miriametro, Antonio; Tan, Hark Hoe; Jagadish, Chennupati; Capizzi, Mario; Polimeni, Antonio

    2015-04-28

    Semiconductor nanowires (NWs) formed by non-nitride III-V compounds grow preferentially with wurtzite (WZ) lattice. This is contrary to bulk and two-dimensional layers of the same compounds, where only zincblende (ZB) is observed. The absorption spectrum of WZ materials differs largely from their ZB counterparts and shows three transitions, referred to as A, B, and C in order of increasing energy, involving the minimum of the conduction band and different critical points of the valence band. In this work, we determine the temperature dependence (T = 10-310 K) of the energy of transitions A, B, and C in ensembles of WZ InP NWs by photoluminescence (PL) and PL excitation (PLE) spectroscopy. For the whole temperature and energy ranges investigated, the PL and PLE spectra are quantitatively reproduced by a theoretical model taking into account contribution from both exciton and continuum states. WZ InP is found to behave very similarly to wide band gap III-nitrides and II-VI compounds, where the energy of A, B, and C displays the same temperature dependence. This finding unveils a general feature of the thermal properties of WZ materials that holds regardless of the bond polarity and energy gap of the crystal. Furthermore, no differences are observed in the temperature dependence of the fundamental band gap energy in WZ InP NWs and ZB InP (both NWs and bulk). This result points to a negligible role played by the WZ/ZB differences in determining the deformation potentials and the extent of the electron-phonon interaction that is a direct consequence of the similar nearest neighbor arrangement in the two lattices.

  1. Temperature dependence of (+)-catechin pyran ring proton coupling constants as measured by NMR and modeled using GMMX search methodology

    Science.gov (United States)

    Fred L. Tobiason; Stephen S. Kelley; M. Mark Midland; Richard W. Hemingway

    1997-01-01

    The pyran ring proton coupling constants for (+)-catechin have been experimentally determined in deuterated methanol over a temperature range of 213 K to 313 K. The experimental coupling constants were simulated to 0.04 Hz on the average at a 90 percent confidence limit using a LAOCOON method. The temperature dependence of the coupling constants was reproduced from the...

  2. Application of three-dimensional reconstruction technology in establishment of atlas space model and sex determination

    International Nuclear Information System (INIS)

    Zhou Jianying; Tian Yong; He Qing; Li Youqiong; Han Qing; Cheng Kailiang

    2013-01-01

    Objective: To establish the method of using the atlas morphological indexes for sex determination in Jilin province and to evaluate its effect. Methods: The clinic neck CT images were used to reconstruct the 3D image of atlas. A total of 27 linear measurement on 8 aspects of the atlas were measured and the ratios were calculated. The 14 items were selected. Results: Of the total 27 linear measurements, 14 were sexually dimorphic (P<0.05), and the accuracies of sex determination of 27 indexes were 52.0% -89.3% . The highest accuracy was width of vertebral body (86.7% ). A function with variables predicting sex with 96.8% accuracy was derived by using stepwise method of discriminant function analysis: Y=1.308W - 0.409CDF - 0.469LTPSD - 0.849LUACD + 0.478RUACD + 0.332RDACD + 0.363ATH - 0.334PTH - 0.236PAL. Conclusion: The method of using atlas traits for sex determination in Jilin province is practicable. (authors)

  3. Sex determination from the radius and ulna in a modern South African sample.

    Science.gov (United States)

    Barrier, I L O; L'Abbé, E N

    2008-07-18

    With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.

  4. Analysis of genes involved in sex determination of fishes by phenol-emulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Ichiro; Nagoya, Hiroyuki; Okamoto, Hiroyuki; Araki, Kazuo [National Research Inst. of Aquaculture, Mie (Japan)

    1998-02-01

    With an aim to clarify the mechanism of sex determination common to vertebrates, the genes presumed to mediate the sex determination were analyzed through cDNA subtraction by phenol-emulsion method. A total RNA was extracted from male juvenile Amago, a kind of oncorhynchus and cDNA was synthesized using mRNA fractionated by oligo-dT column. The male-specific genes expressed in the stage of sex determination was isolated through incorporation to PVC-derived vector. Thus obtained genes were confirmed to be male-specific by Southern hybridization. The results of the screening for the subtracted products indicate that neither of the male-specific clones detected in this study was novel. Previous studies on sex discrimination based on mitochondrial DNA suggested that Sakuramasu and Amago belong in the same species, Oncorhynchus masou masou and the present results show that DNA sequence for male-derived GH pseudo-gene is partially different between the two fishes. (M.N.)

  5. Phylogenetic distribution and evolutionary dynamics of the sex determination genes doublesex and transformer in insects.

    Science.gov (United States)

    Geuverink, E; Beukeboom, L W

    2014-01-01

    Sex determination in insects is characterized by a gene cascade that is conserved at the bottom but contains diverse primary signals at the top. The bottom master switch gene doublesex is found in all insects. Its upstream regulator transformer is present in the orders Hymenoptera, Coleoptera and Diptera, but has thus far not been found in Lepidoptera and in the basal lineages of Diptera. transformer is presumed to be ancestral to the holometabolous insects based on its shared domains and conserved features of autoregulation and sex-specific splicing. We interpret that its absence in basal lineages of Diptera and its order-specific conserved domains indicate multiple independent losses or recruitments into the sex determination cascade. Duplications of transformer are found in derived families within the Hymenoptera, characterized by their complementary sex determination mechanism. As duplications are not found in any other insect order, they appear linked to the haplodiploid reproduction of the Hymenoptera. Further phylogenetic analyses combined with functional studies are needed to understand the evolutionary history of the transformer gene among insects. © 2013 S. Karger AG, Basel.

  6. Heel–Ball index: An analysis of footprint dimensions for determination of sex

    Directory of Open Access Journals (Sweden)

    Tanuj Kanchan

    2014-06-01

    Full Text Available Determination of sex from the footprints recovered at crime scenes can help the investigation by narrowing down the pool of possible suspects. The present research studies the dimensions of the heel and the ball in footprints, and derives the Heel–Ball (HB index from these foot dimensions with the aim to find out if the foot dimensions and the HB index exhibit sexual dimorphisms. The study was carried out on 100 individuals (50 males, 50 females of Indian origin. Footprints were obtained from both feet of the study participants using standard techniques. Thus, a total of 200 footprints were obtained. The breadth of the footprint at ball (BBAL and the breadth of the footprint at heel (BHEL were measured on the footprints. The HB index was derived as (BHEL ÷ BBAL × 100. The footprint measurements at the ball and heel were significantly larger in males on both the sides. Likewise, the derived HB index was larger in males in both feet, but the sex differences were not statistically significant. The study concludes that though footprint dimensions can be used in the determination of sex, the HB index may not be utilized in sex determination from footprints.

  7. Sex determination from hand and foot dimensions in a North Indian population.

    Science.gov (United States)

    Krishan, Kewal; Kanchan, Tanuj; Sharma, Abhilasha

    2011-03-01

    Hands and feet are often recovered from the site of natural as well as man-made disasters because of bomb blasts, train accidents, plane crashes, or mass homicides. This study is intended to establish standards for determination of sex from the dimensions of hands and feet in a North Indian population. The data for this study comprise 123 men and 123 women aged between 17 and 20 years from the "Rajput" population of Himachal Pradesh in North India. Four anthropometric measurements viz. hand length, hand breadth, foot length, and foot breadth have been taken on both sides of each subject following international anthropometric standards. The hand index (hand breadth/hand length × 100) and the foot index (foot breadth/foot length × 100) were calculated. Sectioning points and regression models are derived for the hand and foot dimensions and the derived indices. The hand and foot dimensions show a higher accuracy in sex determination by sectioning point analysis when compared to hand and foot index. Of the hand and the foot dimensions, hand breadth and foot breadth showed better accuracy in sex determination. Hand index and foot index remain poor sex discriminators in the study. © 2011 American Academy of Forensic Sciences.

  8. Sex-specific markers developed by next-generation sequencing confirmed an XX/XY sex determination system in bighead carp (Hypophthalmichehys nobilis) and silver carp (Hypophthalmichthys molitrix).

    Science.gov (United States)

    Liu, Haiyang; Pang, Meixia; Yu, Xiaomu; Zhou, Ying; Tong, Jingou; Fu, Beide

    2018-01-05

    Sex-specific markers are powerful tools for identifying sex-determination system in various animals. Bighead carp (Hypophthalmichehys nobilis) and silver carp (Hypophthalmichthys molitrix) are two of the most important edible fish in Asia, which have a long juvenility period that can lasts for 4-5 years. In this study, we found one sex-specific marker by next-generation sequencing together with bioinformatics analysis in bighead carp. The male-specific markers were used to perform molecular sexing in the progenies of artificial gynogenetic diploids and found all progenies (n = 160) were females. Meanwhile, around 1 : 1 sex ratio was observed in a total of 579 juvenile offspring from three other families. To further extend the male-specific region, we performed genome walking and got a male-specific sequence of 8,661 bp. Five pairs of primers were designed and could be used to efficiently distinguish males from females in bighead carp and silver carp. The development of these male-specific markers and results of their molecular sexing in different populations provide strong evidence for a sex determination system of female homogametry or male heterogametry (XX/XY) in bighead carp and silver carp. To the best of our knowledge, this is the first report of effective sex-specific markers in these two large carp species. © The Author(s) 2018. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

  9. Clinical significance of serum sex hormones protein and lipid determination in patients with ulcerative colitis

    International Nuclear Information System (INIS)

    Song Qingzhang; Zhang Min

    2010-01-01

    Objective: To investigate the relationships between changes of serum sex hormones levels and protein-lipid metabolism in patients with ulcerative colitis. Methods: Serum levels of estradiol (E 2 ) pregnenedione (P), prolactin(PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH) (with CLIA), sree testos (T, with RIA) and total-protein (TP), albumin (Alb), globulin (G), albumin/globulinratio (A/G) total-cholesterd (TC), high density lipoprotein cholesterols (LDL-C) (with biochemistry were determined in 72 patients) with ulcerative colitis and 72 controls. Results: The serum levels of T, LH, FSH, TP, Alb, A/G, TC, LDL-C in patients with ulcerative colitis were significantly lower than those in controls (P 2 , PRL in patients with ulcerative colitis were significantly higher than those in controls (P 2 were negatively correlated with TP, A/G and TC (P 2 levels in the female sex (P>0.05) as well as between LH, FSH and T levels in the male sex (P>0.05). Conclusion: The abnormal serum levels of sex hormone might contribute to the development of hypoproteinaemia and lowered lipid levels in patients with ulcerative colitis. Treatment with correction of serum sex hormones levels might be beneficial to the patients. (authors)

  10. Sex determination in Turdus amaurochalinus (Passeriformes: Muscicapidae: morphometrical analysis supported by CHD gene

    Directory of Open Access Journals (Sweden)

    Katyucha Von Kossel de Andrade Silva

    2011-06-01

    Full Text Available Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1 to determine the sex of individuals using genetic techniques, and 2 to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test=4.34, df=40, p=0.0001 and weight (Student t-test=2.08,df=40, p=0.044: females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species. Rev. Biol. Trop. 59 (2: 789- 794. Epub 2011 June 01.

  11. PRECONCEPTION AND PRENATAL DIAGNOSTIC TECHNIQUES ACT 1994 AND ITS MAIN ROLE TO CURB SEX DETERMINATION AND SEX SELECTION

    OpenAIRE

    Adv. Vaishali V. Waghmare; Dr. (Mrs) Hema Menon

    2016-01-01

    India has a male dominated culture where women are treated like a commodity and slave. Our Indian society gives preference only to the Son not to female because of which girls' child is not heartily welcomed and discrimination against girl child still prevails. Sex selective abortion is one of major issue in recent era in relation to violence against women under which the Ultrasonography machine plays an important role of sex detection. Main cause for sex selection are Patriarchal system, Do...

  12. Temperature dependence of APD-based PET scanners

    International Nuclear Information System (INIS)

    Keereman, Vincent; Van Holen, Roel; Vandenberghe, Stefaan; Vanhove, Christian

    2013-01-01

    Purpose: Solid state detectors such as avalanche photodiodes (APDs) are increasingly being used in PET detectors. One of the disadvantages of APDs is the strong decrease of their gain factor with increasing ambient temperature. The light yield of most scintillation crystals also decreases when ambient temperature is increased. Both effects lead to considerable temperature dependence of the performance of APD-based PET scanners. In this paper, the authors propose a model for this dependence and the performance of the LabPET8 APD-based small animal PET scanner is evaluated at different temperatures.Methods: The model proposes that the effect of increasing temperature on the energy histogram of an APD-based PET scanner is a compression of the histogram along the energy axis. The energy histogram of the LabPET system was acquired at 21 °C and 25 °C to verify the validity of this model. Using the proposed model, the effect of temperature on system sensitivity was simulated for different detector temperature coefficients and temperatures. Subsequently, the effect of short term and long term temperature changes on the peak sensitivity of the LabPET system was measured. The axial sensitivity profile was measured at 21 °C and 24 °C following the NEMA NU 4-2008 standard. System spatial resolution was also evaluated. Furthermore, scatter fraction, count losses and random coincidences were evaluated at different temperatures. Image quality was also investigated.Results: As predicted by the model, the photopeak energy at 25 °C is lower than at 21 °C with a shift of approximately 6% per °C. Simulations showed that this results in an approximately linear decrease of sensitivity when temperature is increased from 21 °C to 24 °C and energy thresholds are constant. Experimental evaluation of the peak sensitivity at different temperatures showed a strong linear correlation for short term (2.32 kcps/MBq/°C = 12%/°C, R = −0.95) and long term (1.92 kcps/MBq/°C = 10%/

  13. Delimitation of the embryonic thermosensitive period for sex determination using an embryo growth model reveals a potential bias for sex ratio prediction in turtles.

    Science.gov (United States)

    Girondot, Marc; Monsinjon, Jonathan; Guillon, Jean-Michel

    2018-04-01

    The sexual phenotype of the gonad is dependent on incubation temperature in many turtles, all crocodilians, and some lepidosaurians. At hatching, identification of sexual phenotype is impossible without sacrificing the neonates. For this reason, a general method to infer sexual phenotype from incubation temperatures is needed. Temperature influences sex determination during a specific period of the embryonic development, starting when the gonad begins to form. At constant incubation temperatures, this thermosensitive period for sex determination (TSP) is located at the middle third of incubation duration (MTID). When temperature fluctuates, the position of the thermosensitive period for sex determination can be shifted from the MTID because embryo growth is affected by temperature. A method is proposed to locate the thermosensitive period for sex determination based on modelling the embryo growth, allowing its precise identification from a natural regime of temperatures. Results from natural nests and simulations show that the approximation of the thermosensitive period for sex determination to the middle third of incubation duration may create a quasi-systematic bias to lower temperatures when computing the average incubation temperature during this period and thus a male-bias for sex ratio estimate. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. The temperature dependent strontium isotope fractionation (δ88/86Sr) during calcium carbonate precipitation

    International Nuclear Information System (INIS)

    Fietzke, J.; Eisenhauer, A.

    2006-01-01

    Full text: In order to study the influence of stable isotope fractionation during inorganic and biologically controlled CaCO 3 precipitation we have developed the analytical principles for the measurement of strontium (Sr) isotope fractionation. We have established a measurement protocol for the application on a MC-ICP-MS (AXIOM) using the common bracketing standard technique. The Sr-standard CRM NBS987 was used as reference material for all measurements and to calculate the Sr fractionation. Latter value is expressed by the δ-notation defined as: δ 88/86 Sr = [( 88 Sr/ 86 Sr)sample / ( 88 Sr/ 86 Sr)standard ] * 1000 -1. A first set of experiments focused on the temperature dependency of Sr-isotope fractionation. For this purpose inorganically precipitated aragonite and calcite was prepared under controlled conditions in a temperature range from 10 to 50 o C. In addition, cultured and naturally grown corals were analyzed for their δ 88/86 Sr values. Repeated measurements of IAPSO seawater standard showed a mean δ 88/86 Sr value of 0.383 ± 0.008 (2 SEM) being the isotopically heaviest material measured so far. The first results of the inorganically precipitated aragonite and the natural corals revealed a clear temperature dependency of the δ 88/86 Sr values. For inorganic aragonite the slope of this correlation is about 0.0055 permil/ o C. However, for naturally grown corals (Pavona clavus) a 6 fold steeper slope of 0.033 permil/ o C was determined. This strong temperature dependency implies the potential to use stable Sr isotopes as a new marine (paleo)temperature proxy. (author)

  15. Sex determination using humeral dimensions in a sample from KwaZulu-Natal: an osteometric study.

    Science.gov (United States)

    Ogedengbe, Oluwatosin Olalekan; Ajayi, Sunday Adelaja; Komolafe, Omobola Aderibigbe; Zaw, Aung Khaing; Naidu, Edwin Coleridge Stephen; Okpara Azu, Onyemaechi

    2017-09-01

    The morphological characteristics of the humeral bone has been investigated in recent times with studies showing varying degrees of sexual dimorphism. Osteologists and forensic scientists have shown that sex determination methods based on skeletal measurements are population specific, and these population-specific variations are present in many body dimensions. The present study aims to establish sex identification using osteometric standards for the humerus in a contemporary KwaZulu-Natal population. A total of 11 parameters were measured in a sample of n=211 humeri (males, 113; females, 98) from the osteological collection in the Discipline of Clinical Anatomy, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa. The difference in means for nearly all variables were found to be significantly higher in males compared to females ( P <0.01) with the most effective single parameter for predicting sex being the vertical head diameter having an accuracy of 82.5%. Stepwise discriminant analysis increased the overall accuracy rate to 87.7% when all measurements were jointly applied. We conclude that the humerus is an important bone which can be reliably used for sex determination based on standard metric methods despite minor tribal or ancestral differences amongst an otherwise homogenous population.

  16. Phenotypic differences in teeth dimensions among Chennai population: An aid in sex determination

    Directory of Open Access Journals (Sweden)

    Sreedevi Dharman

    2015-01-01

    Full Text Available Objective: To investigate the presence of sexual dimorphism by studying the size of the teeth among males and females in Chennai population, which aids in sex determination. Materials and Methods: Incisocervical length, mesiodistal and buccolingual diameters were measured in teeth of 60 subjects (30 males, 30 females in the age group of 18-22 years from Chennai population. The differences in the mean values of parameters in males and females were calculated using independent t-test. Discriminant functional analysis was performed to determine the accuracy of sex. Results: Significant differences were found in mean incisocervical length which were found to be larger in males with P < 0.05 in 11, 12, 14, 17, 21, 22, 24, 26, 27, 31, 32, 33, 34, 41, 43, and 45 and with P < 0.001 in 13, 23, 32, 42, 43, and 44, with the exception of 37 and 47 which were larger in females. Mean mesiodistal diameter was larger in males with P < 0.05 in 11, 12, and 21 and with P < 0.001 in 13, 23, 33, and 43. Mean buccolingual diameter was larger in males with P < 0.05 in 12, 21, 31, 33, and 41 and with P < 0.001 in 11, 13, 23, and 43. Accuracy rate of predicting sex based on incisocervical length (17, 23, 47 and mesiodistal diameter (13, 33 was 78.3% and based on buccolingual diameter (13 was 76.7%. Conclusion: Males showed greater sexual dimorphism than females. Application of incisocervical, mesiodistal, and buccolingual dimensional variability among males and females in the Chennai population can aid in sex determination in forensic odontology, as the results showed moderate extent of dimorphism with an overall accuracy rate of predicting sex to be 78%.

  17. Gadd45g is essential for primary sex determination, male fertility and testis development.

    Directory of Open Access Journals (Sweden)

    Heiko Johnen

    Full Text Available In humans and most mammals, differentiation of the embryonic gonad into ovaries or testes is controlled by the Y-linked gene SRY. Here we show a role for the Gadd45g protein in this primary sex differentiation. We characterized mice deficient in Gadd45a, Gadd45b and Gadd45g, as well as double-knockout mice for Gadd45ab, Gadd45ag and Gadd45bg, and found a specific role for Gadd45g in male fertility and testis development. Gadd45g-deficient XY mice on a mixed 129/C57BL/6 background showed varying degrees of disorders of sexual development (DSD, ranging from male infertility to an intersex phenotype or complete gonadal dysgenesis (CGD. On a pure C57BL/6 (B6 background, all Gadd45g(-/- XY mice were born as completely sex-reversed XY-females, whereas lack of Gadd45a and/or Gadd45b did not affect primary sex determination or testis development. Gadd45g expression was similar in female and male embryonic gonads, and peaked around the time of sex differentiation at 11.5 days post-coitum (dpc. The molecular cause of the sex reversal was the failure of Gadd45g(-/- XY gonads to achieve the SRY expression threshold necessary for testes differentiation, resulting in ovary and Müllerian duct development. These results identify Gadd45g as a candidate gene for male infertility and 46,XY sex reversal in humans.

  18. Suitability of foramen magnum measurements in sex determination and their clinical significance.

    Science.gov (United States)

    Tellioglu, A Metin; Durum, Y; Gok, M; Karakas, S; Polat, A G; Karaman, C Z

    2018-01-01

    The foramen magnum provides a transition between fossa cranii posterior and canalis vertebralis. Medulla oblongata, arteria vertebralis and nervus accessorius spinal part pass through the foramen magnum. In this study, we aimed to make the morphometric measurements of the foramen magnum on computed tomography (CT) and to determine the feasibility of sex determination based on these measurements. Besides sex determination, from a clinical aspect, it is important to know the measurements of the foramen magnum in the normal population in terms of diseases characterised by displacement of the posterior fossa structures through foramen magnum to upper cervical spinal canal such as Chiari malformations and syringomyelia. All the data for our study was obtained retrospectively from 100 patients (50 males, 50 females) who had a CT scan of the head and neck region in Adnan Menderes University Hospital, Department of Radiology. To examine the foramen magnum in each and every occipital bone, we measured the foramen magnum's anteroposterior diameter, transverse diameter, the area of the foramen magnum and its circumference. We found that men have a higher average value than women in our study. According to Student's t-test results; in all measured parameters, there is significant difference between the genders (p discriminant function test is performed for all four measurements, the discrimination rate is 64% for all women, 70% for all men and 67% for both genders. As a result of our study, the metric data we obtained will be useful in cases where the skeletons' sex could not be determined by any other methods. We believe that, our study may be useful for other studies in determining of sex from foramen magnum. Our measurements could give some information of the normal ranges of the foramen magnum in normal population, so that this can contribute to the diagnosis process of some diseases by imaging. (Folia Morphol 2018; 77, 1: 99-104).

  19. Temperature dependence of looping rates in a short peptide.

    Science.gov (United States)

    Roccatano, Danilo; Sahoo, Harekrushna; Zacharias, Martin; Nau, Werner M

    2007-03-15

    Knowledge of the influence of chain length and amino acid sequence on the structural and dynamic properties of small peptides in solution provides essential information on protein folding pathways. The combination of time-resolved optical spectroscopy and molecular dynamics (MD) simulation methods has become a powerful tool to investigate the kinetics of end-to-end collisions (looping rates) in short peptides, which are relevant in early protein folding events. We applied the combination of both techniques to study temperature-dependent (280-340 K) looping rates of the Dbo-AlaGlyGln-Trp-NH2 peptide, where Dbo represents a 2,3-diazabicyclo[2.2.2]oct-2-ene-labeled asparagine, which served as a fluorescent probe in the time-resolved spectroscopic experiments. The experimental looping rates increased from 4.8 x 10(7) s(-1) at 283 K to 2.0 x 10(8) s(-1) at 338 K in H2O. The corresponding Arrhenius plot provided as activation parameters Ea = 21.5 +/- 1.0 kJ mol(-1) and ln(A/s-1) = 26.8 +/- 0.2 in H2O. The results in D2O were consistent with a slight solvent viscosity effect, i.e., the looping rates were 10-20% slower. MD simulations were performed with the GROMOS96 force field in a water solvent model, which required first a parametrization of the synthetic amino acid Dbo. After corrections for solvent viscosity effects, the calculated looping rates varied from 1.5 x 10(8) s(-1) at 280 K to 8.2 x 10(8) s(-1) at 340 K in H2O, which was about four times larger than the experimental data. The calculated activation parameters were Ea = 24.7 +/- 1.5 kJ mol(-1) and ln(A/s(-1)) = 29.4 +/- 0.1 in H2O.

  20. MYB transcription factor gene involved in sex determination in Asparagus officinalis.

    Science.gov (United States)

    Murase, Kohji; Shigenobu, Shuji; Fujii, Sota; Ueda, Kazuki; Murata, Takanori; Sakamoto, Ai; Wada, Yuko; Yamaguchi, Katsushi; Osakabe, Yuriko; Osakabe, Keishi; Kanno, Akira; Ozaki, Yukio; Takayama, Seiji

    2017-01-01

    Dioecy is a plant mating system in which individuals of a species are either male or female. Although many flowering plants evolved independently from hermaphroditism to dioecy, the molecular mechanism underlying this transition remains largely unknown. Sex determination in the dioecious plant Asparagus officinalis is controlled by X and Y chromosomes; the male and female karyotypes are XY and XX, respectively. Transcriptome analysis of A. officinalis buds showed that a MYB-like gene, Male Specific Expression 1 (MSE1), is specifically expressed in males. MSE1 exhibits tight linkage with the Y chromosome, specific expression in early anther development and loss of function on the X chromosome. Knockout of the MSE1 orthologue in Arabidopsis induces male sterility. Thus, MSE1 acts in sex determination in A. officinalis. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  1. XX/XY system of sex determination in the geophilomorph centipede Strigamia maritima

    Czech Academy of Sciences Publication Activity Database

    Green, J. E.; Dalíková, Martina; Sahara, K.; Marec, František; Akam, M.

    2016-01-01

    Roč. 11, č. 2 (2016), č. článku e0150292. E-ISSN 1932-6203 R&D Projects: GA AV ČR IAA600960925; GA ČR(CZ) GA14-22765S Institutional support: RVO:60077344 Keywords : sex determination * Strigamia maritima * XX/XY system Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.806, year: 2016 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0150292

  2. Temperature dependence of energy-transducing functions and inhibitor sensitivity in chloroplasts

    Energy Technology Data Exchange (ETDEWEB)

    Schuurmans, J.J.; Veerman, E.C.I.; Francke, J.A.; Torres-Pereira, J.M.G.; Kraayenhof, R.

    1984-01-01

    A comparative analysis of the temperature dependence of energy-transducing reactions in spinach (Spinacia oleracea) chloroplasts and their sensitivity for uncouplers and energy-transfer inhibitors at different temperatures is presented. Arrhenius plots reveal two groups of transitions, around 19/sup 0/C and around 12/sup 0/C. Activities that show transitions around 19/sup 0/C include linear electron flow from water to ferricyanide, its coupled photophosphorylation, the dark-release of the fluorescent probe atebrin, and the slow component of the 515 nm (carotenoid) absorbance decay after a flash. The transitions around 12/sup 0/C are observed with pyocyanine-mediated cyclic photophosphorylation, light- and dithioerythritol-activated ATP hydrolysis, the dark-release of protons, and the fast 515 nm decay component. It is suggested that both groups of temperature transitions are determined by proton displacements in different domains of the exposed thylakoid membranes. The effects of various uncouplers and an energy-transfer inhibitor are temperature dependent. Some uncouplers also show a different relative inhibition of proton uptake and ATP synthesis at lower temperatures. The efficiency of energy transduction (ATP/e/sub 3/) varied with temperature and was optimal around 10/sup 0/C.

  3. Similar temperature dependencies of glycolytic enzymes: an evolutionary adaptation to temperature dynamics?

    Directory of Open Access Journals (Sweden)

    Cruz Luisa Ana B

    2012-12-01

    Full Text Available Abstract Background Temperature strongly affects microbial growth, and many microorganisms have to deal with temperature fluctuations in their natural environment. To understand regulation strategies that underlie microbial temperature responses and adaptation, we studied glycolytic pathway kinetics in Saccharomyces cerevisiae during temperature changes. Results Saccharomyces cerevisiae was grown under different temperature regimes and glucose availability conditions. These included glucose-excess batch cultures at different temperatures and glucose-limited chemostat cultures, subjected to fast linear temperature shifts and circadian sinoidal temperature cycles. An observed temperature-independent relation between intracellular levels of glycolytic metabolites and residual glucose concentration for all experimental conditions revealed that it is the substrate availability rather than temperature that determines intracellular metabolite profiles. This observation corresponded with predictions generated in silico with a kinetic model of yeast glycolysis, when the catalytic capacities of all glycolytic enzymes were set to share the same normalized temperature dependency. Conclusions From an evolutionary perspective, such similar temperature dependencies allow cells to adapt more rapidly to temperature changes, because they result in minimal perturbations of intracellular metabolite levels, thus circumventing the need for extensive modification of enzyme levels.

  4. Temperature dependence of HU values for various water equivalent phantom materials

    International Nuclear Information System (INIS)

    Homolka, P.; Nowotny, R.; Gahleitner, A.

    2002-01-01

    The temperature dependence of water equivalent phantom materials used in radiotherapy and diagnostic imaging has been investigated. Samples of phantom materials based on epoxy resin, polyethylene, a polystyrene-polypropylene mixture and commercially available phantom materials (Solid Water TM , Gammex RMI and Plastic Water TM , Nuclear Associates) were scanned at temperatures from 15 to 40 deg. C and HU values determined. At a reference temperature of 20 deg. C materials optimized for CT applications give HU values close to zero while the commercial materials show an offset of 119.77 HU (Plastic Water) and 27.69 HU (Solid Water). Temperature dependence was lowest for epoxy-based materials (EPX-W: -0.23 HU deg. C -1 ; Solid Water: -0.25 HU deg. C -1 ) and highest for a polyethylene-based material (X0: -0.72 HU deg. C -1 ). A material based on a mixture of polystyrene and polypropylene (PSPP1: -0.27 HU deg. C -1 ) is comparable to epoxy-based materials and water (-0.29 HU deg. C -1 ). (author)

  5. Inferring the temperature dependence of Beremin cleavage model parameters from the Master Curve

    International Nuclear Information System (INIS)

    Cao Yupeng; Hui Hu; Wang Guozhen; Xuan Fuzhen

    2011-01-01

    Research highlights: → Temperature dependence of Beremin model parameters is inferred by Master Curve approach. → Weibull modulus decreases while Weibull stress scale parameter increases with increasing the temperature. → Estimation of Weibull stress parameters in terms of small amounts of specimens leads to a considerable uncertainty. - Abstract: The temperature dependence of Beremin model parameters in the ductile-to-brittle transition region was addressed by employing the Master Curve. Monte Carlo simulation was performed to produce a large number of 1T fracture toughness data randomly drawn from the scatter band at a temperature of interest and thus to determine Beremin model parameters. In terms of the experimental data of a C-Mn steel (the 16MnR steel in China), results revealed that the Weibull modulus, m, decreases with temperature over the lower transition range and remains a constant in the lower-to-mid transition region. The Weibull scale parameter, σ u , increases with temperature over the temperature range of investigated. A small sample may lead to a considerable uncertainty in estimates of the Weibull stress parameters. However, no significant difference was observed for the average of Weibull stress parameters from different sample sizes.

  6. On the temperature dependence of H-U{sub iso} in the riding hydrogen model

    Energy Technology Data Exchange (ETDEWEB)

    Lübben, Jens; Volkmann, Christian [Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077 Göttingen (Germany); Grabowsky, Simon [School of Chemistry and Biochemistry, Stirling Highway 35, WA-6009 Crawley (Australia); Edwards, Alison [Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Morgenroth, Wolfgang [Institut für Geowissenschaften, Abteilung Kristallographie, Goethe-Universität, Altenhöferallee 1, 60438 Frankfurt am Main (Germany); Fabbiani, Francesca P. A. [GZG, Abteilung Kristallographie, Georg-August Universität, Goldschmidtstrasse 1, 37077 Göttingen (Germany); Sheldrick, George M. [Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077 Göttingen (Germany); Dittrich, Birger, E-mail: birger.dittrich@chemie.uni-hamburg.de [Institut für Anorganische und Angewandte Chemie, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Institut für Anorganische Chemie, Georg-August-Universität, Tammannstrasse 4, D-37077 Göttingen (Germany)

    2014-07-01

    The temperature dependence of hydrogen U{sub iso} and parent U{sub eq} in the riding hydrogen model is investigated by neutron diffraction, aspherical-atom refinements and QM/MM and MO/MO cluster calculations. Fixed values of 1.2 or 1.5 appear to be underestimated, especially at temperatures below 100 K. The temperature dependence of H-U{sub iso} in N-acetyl-l-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U{sub iso} below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffraction data to high resolution, collected at temperatures of 9, 30, 50, 75, 100, 150, 200 and 250 K (synchrotron and home source), reproduce neutron results only when evaluated by aspherical-atom refinement models, since these take into account bonding and lone-pair electron density; both invariom and Hirshfeld-atom refinement models enable a more precise determination of the magnitude of H-atom displacements than independent-atom model refinements. Experimental efforts are complemented by computing displacement parameters following the TLS+ONIOM approach. A satisfactory agreement between all approaches is found.

  7. On the temperature dependence of H-Uiso in the riding hydrogen model

    International Nuclear Information System (INIS)

    Lübben, Jens; Volkmann, Christian; Grabowsky, Simon; Edwards, Alison; Morgenroth, Wolfgang; Fabbiani, Francesca P. A.; Sheldrick, George M.; Dittrich, Birger

    2014-01-01

    The temperature dependence of hydrogen U iso and parent U eq in the riding hydrogen model is investigated by neutron diffraction, aspherical-atom refinements and QM/MM and MO/MO cluster calculations. Fixed values of 1.2 or 1.5 appear to be underestimated, especially at temperatures below 100 K. The temperature dependence of H-U iso in N-acetyl-l-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U iso below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffraction data to high resolution, collected at temperatures of 9, 30, 50, 75, 100, 150, 200 and 250 K (synchrotron and home source), reproduce neutron results only when evaluated by aspherical-atom refinement models, since these take into account bonding and lone-pair electron density; both invariom and Hirshfeld-atom refinement models enable a more precise determination of the magnitude of H-atom displacements than independent-atom model refinements. Experimental efforts are complemented by computing displacement parameters following the TLS+ONIOM approach. A satisfactory agreement between all approaches is found

  8. Temperature-dependent striped antiferromagnetism of LaFeAsO in a Green's function approach

    International Nuclear Information System (INIS)

    Liu Guibin; Liu Banggui

    2009-01-01

    We use a Green's function method to study the temperature-dependent average moment and magnetic phase-transition temperature of the striped antiferromagnetism of LaFeAsO, and other similar compounds, as the parents of FeAs-based superconductors. We consider the nearest and the next-nearest couplings in the FeAs layer, and the nearest coupling for inter-layer spin interaction. The dependence of the transition temperature T N and the zero-temperature average spin on the interaction constants is investigated. We obtain an analytical expression for T N and determine our temperature-dependent average spin from zero temperature to T N in terms of unified self-consistent equations. For LaFeAsO, we obtain a reasonable estimation of the coupling interactions with the experimental transition temperature T N = 138 K. Our results also show that a non-zero antiferromagnetic (AFM) inter-layer coupling is essential for the existence of a non-zero T N , and the many-body AFM fluctuations reduce substantially the low-temperature magnetic moment per Fe towards the experimental value. Our Green's function approach can be used for other FeAs-based parent compounds and these results should be useful to understand the physical properties of FeAs-based superconductors.

  9. A complex interaction of imprinted and maternal-effect genes modifies sex determination in Odd Sex (Ods) mice.

    Science.gov (United States)

    Poirier, Christophe; Qin, Yangjun; Adams, Carolyn P; Anaya, Yanett; Singer, Jonathan B; Hill, Annie E; Lander, Eric S; Nadeau, Joseph H; Bishop, Colin E

    2004-11-01

    The transgenic insertional mouse mutation Odd Sex (Ods) represents a model for the long-range regulation of Sox9. The mutation causes complete female-to-male sex reversal by inducing a male-specific expression pattern of Sox9 in XX Ods/+ embryonic gonads. We previously described an A/J strain-specific suppressor of Ods termed Odsm1(A). Here we show that phenotypic sex depends on a complex interaction between the suppressor and the transgene. Suppression can be achieved only if the transgene is transmitted paternally. In addition, the suppressor itself exhibits a maternal effect, suggesting that it may act on chromatin in the early embryo.

  10. Comparison of cranial sex determination by discriminant analysis and logistic regression.

    Science.gov (United States)

    Amores-Ampuero, Anabel; Alemán, Inmaculada

    2016-04-05

    Various methods have been proposed for estimating dimorphism. The objective of this study was to compare sex determination results from cranial measurements using discriminant analysis or logistic regression. The study sample comprised 130 individuals (70 males) of known sex, age, and cause of death from San José cemetery in Granada (Spain). Measurements of 19 neurocranial dimensions and 11 splanchnocranial dimensions were subjected to discriminant analysis and logistic regression, and the percentages of correct classification were compared between the sex functions obtained with each method. The discriminant capacity of the selected variables was evaluated with a cross-validation procedure. The percentage accuracy with discriminant analysis was 78.2% for the neurocranium (82.4% in females and 74.6% in males) and 73.7% for the splanchnocranium (79.6% in females and 68.8% in males). These percentages were higher with logistic regression analysis: 85.7% for the neurocranium (in both sexes) and 94.1% for the splanchnocranium (100% in females and 91.7% in males).

  11. Metric Sex Determination of the Human Coxal Bone on a Virtual Sample using Decision Trees.

    Science.gov (United States)

    Savall, Frédéric; Faruch-Bilfeld, Marie; Dedouit, Fabrice; Sans, Nicolas; Rousseau, Hervé; Rougé, Daniel; Telmon, Norbert

    2015-11-01

    Decision trees provide an alternative to multivariate discriminant analysis, which is still the most commonly used in anthropometric studies. Our study analyzed the metric characterization of a recent virtual sample of 113 coxal bones using decision trees for sex determination. From 17 osteometric type I landmarks, a dataset was built with five classic distances traditionally reported in the literature and six new distances selected using the two-step ratio method. A ten-fold cross-validation was performed, and a decision tree was established on two subsamples (training and test sets). The decision tree established on the training set included three nodes and its application to the test set correctly classified 92% of individuals. This percentage was similar to the data of the literature. The usefulness of decision trees has been demonstrated in numerous fields. They have been already used in sex determination, body mass prediction, and ancestry estimation. This study shows another use of decision trees enabling simple and accurate sex determination. © 2015 American Academy of Forensic Sciences.

  12. Temperature-dependent thermo-elastic properties of s-, p- and d-block liquid metals

    International Nuclear Information System (INIS)

    Singh, R.N.; Arafin, S.; George, A.K.

    2007-01-01

    Thermodynamic relations involving experimentally known physical quantities are used to determine the ratio of specific heats, γ, for s-block (Na, K, Rb, Cs, Mg), d-block (Fe, Co, Ni, Cu, Ag, Au, Zn, Cd, Hg,) and p-block (Al, Ga, In, Tl, Sn, Pb, Sb, Bi, Se, Te) liquid metals. γ is further utilized to determine reliable values for the isothermal compressibility (κ T ) and the specific heat at constant volume (C V ) for these liquid metals near and above the melting temperatures. These data are of considerable significance for various thermo-physical analysis of liquid metals. We have also evaluated the Grueneisen function and its temperature dependence to establish the correlation between the thermal expansion and the elastic response to thermally induced stress. The values of acoustic impedance for liquid metals are evaluated and its physical significance is discussed for the transmission of elastic waves across metallic interfaces

  13. Deciphering the link between doubly uniparental inheritance of mtDNA and sex determination in bivalves: Clues from comparative transcriptomics

    Science.gov (United States)

    Capt, Charlotte; Renaut, Sébastien; Ghiselli, Fabrizio; Milani, Liliana; Johnson, Nathan A.; Sietman, Bernard E.; Stewart, Donald; Breton, Sophie

    2018-01-01

    Bivalves exhibit an astonishing diversity of sexual systems and sex-determining mechanisms. They can be gonochoric, hermaphroditic or androgenetic, with both genetic and environmental factors known to determine or influence sex. One unique sex-determining system involving the mitochondrial genome has also been hypothesized to exist in bivalves with doubly uniparental inheritance (DUI) of mtDNA. However, the link between DUI and sex determination remains obscure. In this study, we performed a comparative gonad transcriptomics analysis for two DUI-possessing freshwater mussel species to better understand the mechanisms underlying sex determination and DUI in these bivalves. We used a BLAST reciprocal analysis to identify orthologs between Venustaconcha ellipsiformis and Utterbackia peninsularis and compared our results with previously published sex-specific bivalve transcriptomes to identify conserved sex-determining genes. We also compared our data with other DUI species to identify candidate genes possibly involved in the regulation of DUI. A total of ∼12,000 orthologous relationships were found, with 2,583 genes differentially expressed in both species. Among these genes, key sex-determining factors previously reported in vertebrates and in bivalves (e.g., Sry, Dmrt1, Foxl2) were identified, suggesting that some steps of the sex-determination pathway may be deeply conserved in metazoans. Our results also support the hypothesis that a modified ubiquitination mechanism could be responsible for the retention of the paternal mtDNA in male bivalves, and revealed that DNA methylation could also be involved in the regulation of DUI. Globally, our results suggest that sets of genes associated with sex determination and DUI are similar in distantly-related DUI species.

  14. Automatic Sex Determination of Skulls Based on a Statistical Shape Model

    Directory of Open Access Journals (Sweden)

    Li Luo

    2013-01-01

    Full Text Available Sex determination from skeletons is an important research subject in forensic medicine. Previous skeletal sex assessments are through subjective visual analysis by anthropologists or metric analysis of sexually dimorphic features. In this work, we present an automatic sex determination method for 3D digital skulls, in which a statistical shape model for skulls is constructed, which projects the high-dimensional skull data into a low-dimensional shape space, and Fisher discriminant analysis is used to classify skulls in the shape space. This method combines the advantages of metrical and morphological methods. It is easy to use without professional qualification and tedious manual measurement. With a group of Chinese skulls including 127 males and 81 females, we choose 92 males and 58 females to establish the discriminant model and validate the model with the other skulls. The correct rate is 95.7% and 91.4% for females and males, respectively. Leave-one-out test also shows that the method has a high accuracy.

  15. MPK-1 ERK controls membrane organization in C. elegans oogenesis via a sex-determination module.

    Science.gov (United States)

    Arur, Swathi; Ohmachi, Mitsue; Berkseth, Matt; Nayak, Sudhir; Hansen, David; Zarkower, David; Schedl, Tim

    2011-05-17

    Tissues that generate specialized cell types in a production line must coordinate developmental mechanisms with physiological demand, although how this occurs is largely unknown. In the Caenorhabditis elegans hermaphrodite, the developmental sex-determination cascade specifies gamete sex in the distal germline, while physiological sperm signaling activates MPK-1/ERK in the proximal germline to control plasma membrane biogenesis and organization during oogenesis. We discovered repeated utilization of a self-contained negative regulatory module, consisting of NOS-3 translational repressor, FEM-CUL-2 (E3 ubiquitin ligase), and TRA-1 (Gli transcriptional repressor), which acts both in sex determination and in physiological demand control of oogenesis, coordinating these processes. In the distal germline, where MPK-1 is not activated, TRA-1 represses the male fate as NOS-3 functions in translational repression leading to inactivation of the FEM-CUL-2 ubiquitin ligase. In the proximal germline, sperm-dependent physiological MPK-1 activation results in phosphorylation-based inactivation of NOS-3, FEM-CUL-2-mediated degradation of TRA-1 and the promotion of membrane organization during oogenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Phylogeny determines flower size-dependent sex allocation at flowering in a hermaphroditic family.

    Science.gov (United States)

    Teixido, A L; Guzmán, B; Staggemeier, V G; Valladares, F

    2017-11-01

    In animal-pollinated hermaphroditic plants, optimal floral allocation determines relative investment into sexes, which is ultimately dependent on flower size. Larger flowers disproportionally increase maleness whereas smaller and less rewarding flowers favour female function. Although floral traits are considered strongly conserved, phylogenetic relationships in the interspecific patterns of resource allocation to floral sex remain overlooked. We investigated these patterns in Cistaceae, a hermaphroditic family. We reconstructed phylogenetic relationships among Cistaceae species and quantified phylogenetic signal for flower size, dry mass and nutrient allocation to floral structures in 23 Mediterranean species using Blomberg's K-statistic. Lastly, phylogenetically-controlled correlational and regression analyses were applied to examine flower size-based allometry in resource allocation to floral structures. Sepals received the highest dry mass allocation, followed by petals, whereas sexual structures increased nutrient allocation. Flower size and resource allocation to floral structures, except for carpels, showed a strong phylogenetic signal. Larger-flowered species allometrically allocated more resources to maleness, by increasing allocation to corollas and stamens. Our results suggest a major role of phylogeny in determining interspecific changes in flower size and subsequent floral sex allocation. This implies that flower size balances the male-female function over the evolutionary history of Cistaceae. While allometric resource investment in maleness is inherited across species diversification, allocation to the female function seems a labile trait that varies among closely related species that have diversified into different ecological niches. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  17. Determinants of condom breakage among female sex workers in Karnataka, India

    Directory of Open Access Journals (Sweden)

    Bradley Janet

    2011-12-01

    Full Text Available Abstract Background Condoms are effective in preventing the transmission of HIV and other sexually transmitted infections, when properly used. However, recent data from surveys of female sex workers (FSWs in Karnataka in south India, suggest that condom breakage rates may be quite high. It is important therefore to quantify condom breakage rates, and examine what factors might precipitate condom breakage, so that programmers can identify those at risk, and develop appropriate interventions. Methods We explored determinants of reported condom breakage in the previous month among 1,928 female sex workers in four districts of Karnataka using data from cross-sectional surveys undertaken from July 2008 to February 2009. Using stepwise multivariate logistic regression, we examined the possible determinants of condom breakage, controlling for several independent variables including the district and client load. Results Overall, 11.4% of FSWs reported at least one condom break in the previous month. FSWs were much more likely to report breakage if under 20 years of age (AOR 3.43, p = 0.005; if divorced/ separated/widowed (AOR 1.52, p = 0.012; if they were regular alcohol users (AOR 1.63, p = 0.005; if they mostly entertained clients in lodges/rented rooms (AOR 2.99, p = 0.029 or brothels (AOR 4.77, p = 0.003, compared to street based sex workers; if they had ever had anal sex (AOR 2.03, p = 0.006; if the sex worker herself (as opposed to the client applied the condom at last use (AOR 1.90, p Conclusions The reported incidence of condom breakage was high in this study, and this is a major concern for HIV/STI prevention programs, for which condom use is a key prevention tool. Younger and more marginalized female sex workers were most vulnerable to condom breakage. Special effort is therefore required to seek out such women and to provide information and skills on correct condom use. More research is also needed on what specific situational parameters

  18. Determinants of condom breakage among female sex workers in Karnataka, India.

    Science.gov (United States)

    Bradley, Janet; Rajaram, S; Alary, Michel; Isac, Shajy; Washington, Reynold; Moses, Stephen; Ramesh, B M

    2011-12-29

    Condoms are effective in preventing the transmission of HIV and other sexually transmitted infections, when properly used. However, recent data from surveys of female sex workers (FSWs) in Karnataka in south India, suggest that condom breakage rates may be quite high. It is important therefore to quantify condom breakage rates, and examine what factors might precipitate condom breakage, so that programmers can identify those at risk, and develop appropriate interventions. We explored determinants of reported condom breakage in the previous month among 1,928 female sex workers in four districts of Karnataka using data from cross-sectional surveys undertaken from July 2008 to February 2009. Using stepwise multivariate logistic regression, we examined the possible determinants of condom breakage, controlling for several independent variables including the district and client load. Overall, 11.4% of FSWs reported at least one condom break in the previous month. FSWs were much more likely to report breakage if under 20 years of age (AOR 3.43, p = 0.005); if divorced/ separated/widowed (AOR 1.52, p = 0.012); if they were regular alcohol users (AOR 1.63, p = 0.005); if they mostly entertained clients in lodges/rented rooms (AOR 2.99, p = 0.029) or brothels (AOR 4.77, p = 0.003), compared to street based sex workers; if they had ever had anal sex (AOR 2.03, p = 0.006); if the sex worker herself (as opposed to the client) applied the condom at last use (AOR 1.90, p < 0.001); if they were inconsistent condom users (AOR 2.77, p < 0.001); and if they had never seen a condom demonstration (AOR 2.37, p < 0.001). The reported incidence of condom breakage was high in this study, and this is a major concern for HIV/STI prevention programs, for which condom use is a key prevention tool. Younger and more marginalized female sex workers were most vulnerable to condom breakage. Special effort is therefore required to seek out such women and to provide information and skills on correct

  19. Evidence for the evolutionary nascence of a novel sex determination pathway in honeybees

    DEFF Research Database (Denmark)

    Hasselmann, Martin; Gempe, Tanja; Schiøtt, Morten

    2008-01-01

    and hemizygotes (haploid individuals) are males. Although at least 15 different csd alleles are known among natural bee populations, the mechanisms linking allelic interactions to switching of the sexual development programme are still obscure. Here we report a new component of the sex-determining pathway...... in honeybees, encoded 12 kilobases upstream of csd. The gene feminizer (fem) is the ancestrally conserved progenitor gene from which csd arose and encodes an SR-type protein, harbouring an Arg/Ser-rich domain. Fem shares the same arrangement of Arg/Ser- and proline-rich-domain with the Drosophila principal sex......, whereas the female-specific splice variant encodes the functional protein. We show that RNA interference (RNAi)-induced knockdowns of the female-specific fem splice variant result in male bees, indicating that the fem product is required for entire female development. Furthermore, RNAi-induced knockdowns...

  20. Sex determination by tooth size in a sample of Greek population.

    Science.gov (United States)

    Mitsea, A G; Moraitis, K; Leon, G; Nicopoulou-Karayianni, K; Spiliopoulou, C

    2014-08-01

    Sex assessment from tooth measurements can be of major importance for forensic and bioarchaeological investigations, especially when only teeth or jaws are available. The purpose of this study is to assess the reliability and applicability of establishing sex identity in a sample of Greek population using the discriminant function proposed by Rösing et al. (1995). The study comprised of 172 dental casts derived from two private orthodontic clinics in Athens. The individuals were randomly selected and all had clear medical history. The mesiodistal crown diameters of all the teeth were measured apart from those of the 3rd molars. The values quoted for the sample to which the discriminant function was first applied were similar to those obtained for the Greek sample. The results of the preliminary statistical analysis did not support the use of the specific discriminant function for a reliable determination of sex by means of the mesiodistal diameter of the teeth. However, there was considerable variation between different populations and this might explain the reason for lack of discriminating power of the specific function in the Greek population. In order to investigate whether a better discriminant function could be obtained using the Greek data, separate discriminant function analysis was performed on the same teeth and a different equation emerged without, however, any real improvement in the classification process, with an overall correct classification of 72%. The results showed that there were a considerably higher percentage of females correctly classified than males. The results lead to the conclusion that the use of the mesiodistal diameter of teeth is not as a reliable method as one would have expected for determining sex of human remains from a forensic context. Therefore, this method could be used only in combination with other identification approaches. Copyright © 2014. Published by Elsevier GmbH.

  1. Temperature dependence of microwave oscillations in magnetic tunnel junctions with a perpendicularly magnetized free layer

    International Nuclear Information System (INIS)

    Guo, Peng; Feng, Jiafeng; Wei, Hongxiang; Han, Xiufeng; Fang, Bin; Zhang, Baoshun; Zeng, Zhongming

    2015-01-01

    We experimentally study the temperature dependence of the spin-transfer-torque-induced microwave oscillations in MgO-based magnetic tunnel junction nanopillars with a perpendicularly magnetized free layer. We demonstrate that the oscillation frequency increases rapidly with decreasing temperature, which is mainly ascribed to the temperature dependence of both the saturation magnetization and the perpendicular magnetic anisotropy. We also find that a strong temperature dependence of the output power while a nonmonotonic temperature dependence of spectral linewidth are maintained for a constant dc bias in measured temperature range. Possible mechanisms leading to the different dependences of oscillation frequency, output power, and linewidth are discussed

  2. Understanding Biological Rates and their Temperature Dependence, from Enzymes to Ecosystems

    Science.gov (United States)

    Prentice, E.; Arcus, V. L.

    2017-12-01

    Temperature responses over various scales in biological systems follow a similar pattern; negative curvature results in an optimum temperature (Topt) for activity/growth/turnover, with decreases in rates on either side of Topt. Previously this downturn in rates at high temperatures has been attributed to enzyme denaturation, where a failing of the basic driving units of metabolism was used to describe curvature at the enzyme and organism level. However, recent developments in our understanding of the factors governing enzyme rates at different temperatures have guided a new understanding of the responses of biological systems. Enzymes catalyse reactions by driving the substrate through a high energy species, which is tightly bound to the enzyme. Macromolecular rate theory (MMRT) has recently been developed to account for the changes in the system brought about by this tight binding, specifically the change in the physical parameter heat capacity (ΔCǂp), and the effect this has on the temperature dependence of enzyme reactions. A negative ΔCǂp imparts the signature negative curvature to rates in the absence of denaturation, and finds that Topt, ΔCǂp and curvature are all correlated, placing constraints on biological systems. The simplest of cells comprise thousands of enzymatically catalysed reactions, functioning in series and in parallel in metabolic pathways to determine the overall growth rate of an organism. Intuitively, the temperature effects of enzymes play a role in determining the overall temperature dependence of an organism, in tandem with cellular level regulatory responses. However, the effect of individual Topt values and curvature on overall pathway behaviour is less apparent. Here, this is investigated in the context of MMRT through the in vitro characterisation of a six-step metabolic pathway to understand the steps in isolation and functioning in series. Pathway behaviour is found to be approximately an average of the properties of the

  3. Glass transition in thaumatin crystals revealed through temperature-dependent radiation-sensitivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Warkentin, Matthew, E-mail: maw64@cornell.edu; Thorne, Robert E. [Physics Department, Cornell University, Ithaca, New York (United States)

    2010-10-01

    Radiation damage to protein crystals exhibits two regimes of temperature-activated behavior between T = 300 and 100 K, with a crossover at the protein glass transition near 200 K. These results have implications for mechanistic studies of proteins and for structure determination when cooling to T = 100 K creates excessive disorder. The temperature-dependence of radiation damage to thaumatin crystals between T = 300 and 100 K is reported. The amount of damage for a given dose decreases sharply as the temperature decreases from 300 to 220 K and then decreases more gradually on further cooling below the protein-solvent glass transition. Two regimes of temperature-activated behavior were observed. At temperatures above ∼200 K the activation energy of 18.0 kJ mol{sup −1} indicates that radiation damage is dominated by diffusive motions in the protein and solvent. At temperatures below ∼200 K the activation energy is only 1.00 kJ mol{sup −1}, which is of the order of the thermal energy. Similar activation energies describe the temperature-dependence of radiation damage to a variety of solvent-free small-molecule organic crystals over the temperature range T = 300–80 K. It is suggested that radiation damage in this regime is vibrationally assisted and that the freezing-out of amino-acid scale vibrations contributes to the very weak temperature-dependence of radiation damage below ∼80 K. Analysis using the radiation-damage model of Blake and Phillips [Blake & Phillips (1962 ▶), Biological Effects of Ionizing Radiation at the Molecular Level, pp. 183–191] indicates that large-scale conformational and molecular motions are frozen out below T = 200 K but become increasingly prevalent and make an increasing contribution to damage at higher temperatures. Possible alternative mechanisms for radiation damage involving the formation of hydrogen-gas bubbles are discussed and discounted. These results have implications for mechanistic studies of proteins and for

  4. GLOBAL EPIDEMIOLOGY OF HIV AMONG FEMALE SEX WORKERS: INFLUENCE OF STRUCTURAL DETERMINANTS

    Science.gov (United States)

    Shannon, K; Strathdee, SA; Goldenberg, SM; Duff, P; Mwangi, P; Rusakova, M; Reza-Paul, S; Lau, J; Deering, K; Pickles, M; Boily, M-C

    2014-01-01

    SUMMARY Female sex workers (FSWs) bear a disproportionately large burden of HIV infection worldwide. Despite decades of research and programme activity, the epidemiology of HIV and the role that structural determinants have in mitigating or potentiating HIV epidemics and access to care for FSWs is poorly understood. We reviewed available published data for HIV prevalence and incidence, condom use, and structural determinants among this group. Only 87 (43%) of 204 unique studies reviewed explicitly examined structural determinants of HIV. Most studies were from Asia, with few from areas with a heavy burden of HIV such as sub-Saharan Africa, Russia, and eastern Europe. To further explore the potential effect of structural determinants on the course of epidemics, we used a deterministic transmission model to simulate potential HIV infections averted through structural changes in regions with concentrated and generalised epidemics, and high HIV prevalence among FSWs. This modelling suggested that elimination of sexual violence alone could avert 17% of HIV infections in Kenya (95% uncertainty interval [UI] 1–31) and 20% in Canada (95% UI 3–39) through its immediate and sustained effect on non-condom use) among FSWs and their clients in the next decade. In Kenya, scaling up of access to antiretroviral therapy among FSWs and their clients to meet WHO eligibility of a CD4 cell count of less than 500 cells per μL could avert 34% (95% UI 25–42) of infections and even modest coverage of sex worker-led outreach could avert 20% (95% UI 8–36) of infections in the next decade. Decriminalisation of sex work would have the greatest effect on the course of HIV epidemics across all settings, averting 33–46% of HIV infections in the next decade. Multipronged structural and community-led interventions are crucial to increase access to prevention and treatment and to promote human rights for FSWs worldwide. PMID:25059947

  5. Temperature dependence of the fundamental excitonic resonance in lead-salt quantum dots

    International Nuclear Information System (INIS)

    Yue, Fangyu; Tomm, Jens W.; Kruschke, Detlef; Ullrich, Bruno; Chu, Junhao

    2015-01-01

    The temperature dependences of the fundamental excitonic resonance in PbS and PbSe quantum dots fabricated by various technologies are experimentally determined. Above ∼150 K, sub-linearities of the temperature shifts and halfwidths are observed. This behavior is analyzed within the existing standard models. Concordant modeling, however, becomes possible only within the frame of a three-level system that takes into account both bright and dark excitonic states as well as phonon-assisted carrier redistribution between these states. Our results show that luminescence characterization of lead-salt quantum dots necessarily requires both low temperatures and excitation densities in order to provide reliable ensemble parameters

  6. Temperature dependent lattice constant of InSb above room temperature

    Science.gov (United States)

    Breivik, Magnus; Nilsen, Tron Arne; Fimland, Bjørn-Ove

    2013-10-01

    Using temperature dependent X-ray diffraction on two InSb single crystalline substrates, the bulk lattice constant of InSb was determined between 32 and 325 °C. A polynomial function was fitted to the data: a(T)=6.4791+3.28×10-5×T+1.02×10-8×T2 Å (T in °C), which gives slightly higher values than previously published (which go up to 62 °C). From the fit, the thermal expansion of InSb was calculated to be α(T)=5.062×10-6+3.15×10-9×T K-1 (T in °C). We found that the thermal expansion coefficient is higher than previously published values above 100 °C (more than 10% higher at 325 °C).

  7. Temperature dependent electrical characteristics of Zn/ZnSe/n-GaAs/In structure

    Science.gov (United States)

    Sağlam, M.; Güzeldir, B.

    2016-04-01

    We have reported a study of the I-V characteristics of Zn/ZnSe/n-GaAs/In sandwich structure in a wide temperature range of 80-300 K by a step of 20 K, which are prepared by Successive Ionic Layer Adsorption and Reaction (SILAR) method. The main electrical parameters, such as ideality factor and zero-bias barrier height determined from the forward bias I-V characteristics were found strongly depend on temperature and when the increased, the n decreased with increasing temperature. The ideality factor and barrier height values as a function of the sample temperature have been attributed to the presence of the lateral inhomogeneities of the barrier height. Furthermore, the series resistance have been calculated from the I-V measurements as a function of temperature dependent.

  8. Temperature dependence of the optical absorption spectra of InP/ZnS quantum dots

    Science.gov (United States)

    Savchenko, S. S.; Vokhmintsev, A. S.; Weinstein, I. A.

    2017-03-01

    The optical-absorption spectra of InP/ZnS (core/shell) quantum dots have been studied in a broad temperature range of T = 6.5-296 K. Using the second-order derivative spectrophotometry technique, the energies of optical transitions at room temperature were found to be E 1 = 2.60 ± 0.02 eV (for the first peak of excitonic absorption in the InP core) and E 2 = 4.70 ± 0.02 eV (for processes in the ZnS shell). The experimental curve of E 1( T) has been approximated for the first time in the framework of a linear model and in terms of the Fan's formula. It is established that the temperature dependence of E 1 is determined by the interaction of excitons and longitudinal acoustic phonons with hω = 15 meV.

  9. Sex determination in beetles: Production of all male progeny by Parental RNAi knockdown of transformer

    Science.gov (United States)

    Shukla, Jayendra Nath; Palli, Subba Reddy

    2012-01-01

    Sex in insects is determined by a cascade of regulators ultimately controlling sex-specific splicing of a transcription factor, Doublesex (Dsx). We recently identified homolog of dsx in the red flour beetle, Tribolium castaneum (Tcdsx). Here, we report on the identification and characterization of a regulator of Tcdsx splicing in T. castaneum. Two male-specific and one female-specific isoforms of T. castaneum transformer (Tctra) were identified. RNA interference-aided knockdown of Tctra in pupa or adults caused a change in sex from females to males by diverting the splicing of Tcdsx pre-mRNA to male-specific isoform. All the pupa and adults developed from Tctra dsRNA injected final instar larvae showed male-specific sexually dimorphic structures. Tctra parental RNAi caused an elimination of females from the progeny resulting in production of all male progeny. Transformer parental RNAi could be used to produce all male population for use in pest control though sterile male release methods. PMID:22924109

  10. Fibroblast growth factor receptor 2 regulates proliferation and Sertoli differentiation during male sex determination

    Science.gov (United States)

    Kim, Yuna; Bingham, Nathan; Sekido, Ryohei; Parker, Keith L.; Lovell-Badge, Robin; Capel, Blanche

    2007-01-01

    Targeted mutagenesis of Fgf9 in mice causes male-to-female sex reversal. Among the four FGF receptors, FGFR2 showed two highly specific patterns based on antibody staining, suggesting that it might be the receptor-mediating FGF9 signaling in the gonad. FGFR2 was detected at the plasma membrane in proliferating coelomic epithelial cells and in the nucleus in Sertoli progenitor cells. This expression pattern suggested that Fgfr2 might play more than one role in testis development. To test the hypothesis that Fgfr2 is required for male sex determination, we crossed mice carrying a floxed allele of Fgfr2 with two different Cre lines to induce a temporal or cell-specific deletion of this receptor. Results show that deletion of Fgfr2 in embryonic gonads phenocopies deletion of Fgf9 and leads to male-to-female sex reversal. Using these two Cre lines, we provide the first genetic evidence that Fgfr2 plays distinct roles in proliferation and Sertoli cell differentiation during testis development. PMID:17940049

  11. Time, stress, and temperature-dependent deformation in nanostructured copper: Stress relaxation tests and simulations

    International Nuclear Information System (INIS)

    Yang, Xu-Sheng; Wang, Yun-Jiang; Wang, Guo-Yong; Zhai, Hui-Ru; Dai, L.H.; Zhang, Tong-Yi

    2016-01-01

    In the present work, stress relaxation tests, high-resolution transmission electron microscopy (HRTEM), and molecular dynamics (MD) simulations were conducted on coarse-grained (cg), nanograined (ng), and nanotwinned (nt) copper at temperatures of 22 °C (RT), 30 °C, 40 °C, 50 °C, and 75 °C. The comprehensive investigations provide sufficient information for the building-up of a formula to describe the time, stress, and temperature-dependent deformation and clarify the relationship among the strain rate sensitivity parameter, stress exponent, and activation volume. The typically experimental curves of logarithmic plastic strain rate versus stress exhibited a three staged relaxation process from a linear high stress relaxation region to a subsequent nonlinear stress relaxation region and finally to a linear low stress relaxation region, which only showed-up at the test temperatures higher than 22 °C, 22 °C, and 30 °C, respectively, in the tested cg-, ng-, and nt-Cu specimens. The values of stress exponent, stress-independent activation energy, and activation volume were determined from the experimental data in the two linear regions. The determined activation parameters, HRTEM images, and MD simulations consistently suggest that dislocation-mediated plastic deformation is predominant in all tested cg-, ng-, and nt-Cu specimens in the initial linear high stress relaxation region at the five relaxation temperatures, whereas in the linear low stress relaxation region, the grain boundary (GB) diffusion-associated deformation is dominant in the ng- and cg-Cu specimens, while twin boundary (TB) migration, i.e., twinning and detwinning with parallel partial dislocations, governs the time, stress, and temperature-dependent deformation in the nt-Cu specimens.

  12. Temperature dependent optical properties of ZnO thin film using ellipsometry and photoluminescence

    Science.gov (United States)

    Bouzourâa, M.-B.; Battie, Y.; Dalmasso, S.; Zaïbi, M.-A.; Oueslati, M.; En Naciri, A.

    2018-05-01

    We report the temperature dependence of the dielectric function, the exciton binding energy and the electronic transitions of crystallized ZnO thin film using spectroscopic ellipsometry (SE) and photoluminescence (PL). ZnO layers were prepared by sol-gel method and deposited on crystalline silicon (Si) by spin coating technique. The ZnO optical properties were determined between 300 K and 620 K. Rigorous study of optical responses was achieved in order to demonstrate the quenching exciton of ZnO as a function of temperature. Numerical technique named constrained cubic splines approximation (CCS), Tauc-Lorentz (TL) and Tanguy dispersion models were selected for the ellipsometry data modeling in order to obtain the dielectric function of ZnO. The results reveals that the exciton bound becomes widely flattening at 470 K on the one hand, and on the other that the Tanguy dispersion law is more appropriate for determining the optical responses of ZnO thin film in the temperature range of 300 K-420 K. The Tauc-Lorentz, for its part, reproduces correctly the ZnO dielectric function in 470 K-620 K temperature range. The temperature dependence of the electronic transition given by SE and PL shows that the exciton quenching was observed in 420 K-∼520 K temperature range. This quenching effect can be explained by the equilibrium between the Coulomb force of exciton and its kinetic energy in the film. The kinetic energy was found to induce three degrees of freedom of the exciton.

  13. Sexual dimorphism in mammalian autosomal gene regulation is determined not only by Sry but by sex chromosome complement as well.

    Science.gov (United States)

    Wijchers, Patrick J; Yandim, Cihangir; Panousopoulou, Eleni; Ahmad, Mushfika; Harker, Nicky; Saveliev, Alexander; Burgoyne, Paul S; Festenstein, Richard

    2010-09-14

    Differences between males and females are normally attributed to developmental and hormonal differences between the sexes. Here, we demonstrate differences between males and females in gene silencing using a heterochromatin-sensitive reporter gene. Using "sex-reversal" mouse models with varying sex chromosome complements, we found that this differential gene silencing was determined by X chromosome complement, rather than sex. Genome-wide transcription profiling showed that the expression of hundreds of autosomal genes was also sensitive to sex chromosome complement. These genome-wide analyses also uncovered a role for Sry in modulating autosomal gene expression in a sex chromosome complement-specific manner. The identification of this additional layer in the establishment of sexual dimorphisms has implications for understanding sexual dimorphisms in physiology and disease. Copyright © 2010 Elsevier Inc. All rights reserved.

  14. The role of Fanconi anemia/BRCA genes in zebrafish sex determination.

    Science.gov (United States)

    Rodríguez-Marí, Adriana; Postlethwait, John H

    2011-01-01

    Fanconi anemia (FA) is a human disease of bone marrow failure, leukemia, squamous cell carcinoma, and developmental anomalies, including hypogonadism and infertility. Bone marrow transplants improve hematopoietic phenotypes but do not prevent other cancers. FA arises from mutation in any of the 15 FANC genes that cooperate to repair double stranded DNA breaks by homologous recombination. Zebrafish has a single ortholog of each human FANC gene and unexpectedly, mutations in at least two of them (fancl and fancd1(brca2)) lead to female-to-male sex reversal. Investigations show that, as in human, zebrafish fanc genes are required for genome stability and for suppressing apoptosis in tissue culture cells, in embryos treated with DNA damaging agents, and in meiotic germ cells. The sex reversal phenotype requires the action of Tp53 (p53), an activator of apoptosis. These results suggest that in normal sex determination, zebrafish oocytes passing through meiosis signal the gonadal soma to maintain expression of aromatase, an enzyme that converts androgen to estrogen, thereby feminizing the gonad and the individual. According to this model, normal male and female zebrafish differ in genetic factors that control the strength of the late meiotic oocyte-derived signal, probably by regulating the number of meiotic oocytes, which environmental factors can also alter. Transcripts from fancd1(brca2) localize at the animal pole of the zebrafish oocyte cytoplasm and are required for normal oocyte nuclear architecture, for normal embryonic development, and for preventing ovarian tumors. Embryonic DNA repair and sex reversal phenotypes provide assays for the screening of small molecule libraries for therapeutic substances for FA. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Theory of the temperature dependence of positron bulk lifetimes-implications for vacancy formation enthalpy measurements via positron experiments

    International Nuclear Information System (INIS)

    Tam, S.W.; Sinha, S.K.; Siegel, R.W.

    1977-02-01

    Temperature dependent effects, which may have a bearing on determinations of vacancy formation enthalpies in metals by positron annihilation, have been observed in certain metals. These effects have been observed to occur both at temperatures below those at which positron annihilation is most sensitive to equilibrium vacancies and at temperatures well within the vacancy-sensitive region. The effect of thermal lattice displacements on positron lifetimes in metals was investigated to help understand these phenomena

  16. Rate of egg maturation in marine turtles exhibits 'universal temperature dependence'.

    Science.gov (United States)

    Weber, Sam B; Blount, Jonathan D; Godley, Brendan J; Witt, Matthew J; Broderick, Annette C

    2011-09-01

    1. The metabolic theory of ecology (MTE) predicts that, after correcting for body mass variation among organisms, the rates of most biological processes will vary as a universal function of temperature. However, empirical support for 'universal temperature dependence' (UTD) is currently equivocal and based on studies of a limited number of traits. 2. In many ectothermic animals, the rate at which females produce mature eggs is temperature dependent and may be an important factor in determining the costs of reproduction. 3. We tested whether the rate of egg maturation in marine turtles varies with environmental temperature as predicted by MTE, using the time separating successive clutches of individual females to estimate the rate at which eggs are formed. We also assessed the phenotypic contribution to this rate, by using radio telemetry to make repeated measurements of interclutch intervals for individual green turtles (Chelonia mydas). 4. Rates of egg maturation increased with seasonally increasing water temperatures in radio-tracked green turtles, but were not repeatable for individual females, and did not vary according to maternal body size or reproductive investment (number and size of eggs produced). 5. Using a collated data set from several different populations and species of marine turtles, we then show that a single relationship with water temperature explains most of the variation in egg maturation rates, with a slope that is statistically indistinguishable from the UTD predicted by MTE. However, several alternative statistical models also described the relationship between temperature and egg maturation rates equally parsimoniously. 6. Our results offer novel support for the MTE's predicted UTD of biological rates, although the underlying mechanisms require further study. The strong temperature dependence of egg maturation combined with the apparently weak phenotypic contribution to this rate has interesting behavioural implications in ectothermic

  17. The roles of Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes in sex determination and differentiation mechanisms: Ubiquity and diversity across the animal kingdom.

    Science.gov (United States)

    Picard, Marion Anne-Lise; Cosseau, Céline; Mouahid, Gabriel; Duval, David; Grunau, Christoph; Toulza, Ève; Allienne, Jean-François; Boissier, Jérôme

    2015-07-01

    The Dmrt (Double sex/Male-abnormal-3 Related Transcription factor) genes have been intensively studied because they represent major transcription factors in the pathways governing sex determination and differentiation. These genes have been identified in animal groups ranging from cnidarians to mammals, and some of the genes functionally studied. Here, we propose to analyze (i) the presence/absence of various Dmrt gene groups in the different taxa across the animal kingdom; (ii) the relative expression levels of the Dmrt genes in each sex; (iii) the specific spatial (by organ) and temporal (by developmental stage) variations in gene expression. This review considers non-mammalian animals at all levels of study (i.e. no particular importance is given to animal models), and using all types of sexual strategy (hermaphroditic or gonochoric) and means of sex determination (i.e. genetic or environmental). To conclude this global comparison, we offer an analysis of the DM domains conserved among the different DMRT proteins, and propose a general sex-specific pattern for each member of the Dmrt gene family. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  18. Inclusion of temperature dependence of fission barriers in statistical model calculations

    International Nuclear Information System (INIS)

    Newton, J.O.; Popescu, D.G.; Leigh, J.R.

    1990-08-01

    The temperature dependence of fission barriers has been interpolated from the results of recent theoretical calculations and included in the statistical model code PACE2. It is shown that the inclusion of temperature dependence causes significant changes to the values of the statistical model parameters deduced from fits to experimental data. 21 refs., 2 figs

  19. Sex Reversal in Reptiles: Reproductive Oddity or Powerful Driver of Evolutionary Change?

    Science.gov (United States)

    Holleley, Clare E; Sarre, Stephen D; O'Meally, Denis; Georges, Arthur

    2016-01-01

    Is sex a product of genes, the environment, or both? In this review, we describe the diversity of sex-determining mechanisms in reptiles, with a focus on systems that display gene-environment interactions. We summarise the field and laboratory-based evidence for the occurrence of environmental sex reversal in reptiles and ask whether this is a widespread evolutionary mechanism affecting the evolution of sex chromosomes and speciation in vertebrates. Sex determination systems exist across a continuum of genetic and environmental influences, blurring the lines between what was once considered a strict dichotomy between genetic sex determination and temperature-dependent sex determination. Across this spectrum, we identify the potential for sex reversal in species with clearly differentiated heteromorphic sex chromosomes (Pogona vitticeps, Bassiana duperreyi, Eremias multiocellata, Gekko japonicus), weakly differentiated homomorphic sex chromosomes (Niveoscincus ocellatus), and species with only a weak heritable predisposition for sex (Emys orbicularis, Trachemys scripta). We argue that sex reversal is widespread in reptiles (Testudines, Lacertidae, Agamidae, Scincidae, Gekkonidae) and has the potential to have an impact on individual fitness, resulting in reproductively, morphologically, and behaviourally unique phenotypes. Sex reversal is likely to be a powerful evolutionary force responsible for generating and maintaining lability and diversity in reptile sex-determining modes. © 2016 S. Karger AG, Basel.

  20. Aerobic vs. anaerobic scope: sibling species of fish indicate that temperature dependence of hypoxia tolerance can predict future survival.

    Science.gov (United States)

    Sørensen, Christina; Munday, Philip L; Nilsson, Göran E

    2014-03-01

    The temperature dependence of aerobic scope has been suggested to be a major determinant of how marine animals will cope with future rises in environmental temperature. Here, we present data suggesting that in some animals, the temperature dependence of anaerobic scope (i.e., the capacity for surviving severe hypoxia) may determine present-day latitudinal distributions and potential for persistence in a warmer future. As a model for investigating the role of anaerobic scope, we studied two sibling species of coral-dwelling gobies, Gobiodon histrio, and G. erythrospilus, with different latitudinal distributions, but which overlap in equal abundance at Lizard Island (14°40'S) on the Great Barrier Reef. These species did not differ in the temperature dependence of resting oxygen consumption or critical oxygen concentration (the lowest oxygen level where resting oxygen consumption can be maintained). In contrast, the more equatorial species (G. histrio) had a better capacity to endure anaerobic conditions at oxygen levels below the critical oxygen concentration at the high temperatures (32-33 °C) more likely to occur near the equator, or in a warmer future. These results suggest that anaerobic scope, in addition to aerobic scope, could be important in determining the impacts of global warming on some marine animals. © 2013 John Wiley & Sons Ltd.

  1. Genetic studies on sex determination and colouration in Nile tilapia (Oreochromis niloticus L.)

    International Nuclear Information System (INIS)

    Karayuecel, I.

    1999-05-01

    The present study was undertaken to investigate colour and sex determination mechanisms through the application of androgenesis, gynogenesis and controlled breeding programme with the objective of producing all red males in O. niloticus. The highest yield of androgenetic haploid to pigmentation stage was 24.6±3.5% (relative to controls) with optimal UV irradiation dose of 450JM -2 for 5 minutes. The highest survival rate of diploid androgens was 0.07±0.07% (relative to controls) to yolk sac stage using a heat shock of 42.5 deg. C for 3 minutes 30 seconds applied at 25 minutes after fertilisation. All paternal inheritance of diploid androgenetic tilapia was verified using DNA fingerprinting. The mean recombination frequency of the red skin colour gene in meiotic gynogens was 0.12±0.04. All maternal inheritance of meiotic gynogens was verified using the isozyme locus ADA*. Analyses of sex ratios of meiotic gynogens suggested that male progenies were produced by an epistatic sex determining locus (SDL-2 with two alleles SR and sr) causing female to male sex reversal in the homozygous phase (srsr) but with limited penetrance. A close linkage was found between a sex determining locus (SDL-2) and the red gene. No significant difference was found between colour genotypes (namely homozygous red, heterozygous red and wild type) in terms of total fecundity, ISI (inter spawning interval), egg size and survival rate. Overall mean ISI was 26.3±1.0 days. Mean total fecundity was 1096 eggs. Fecundity varied over successive spawns but this variation did not appear to be related to spawning periodicity. Hormonal and thermal feminization were compared on all YY male progeny of O. niloticus. While similar female percentages of 32.0±5.2 and 33.8±1.5% were produced, significantly higher intersex percentages of 18.5±2.5 and 1.6±0.8 were observed in heat and DES treated groups, respectively. Heat treatment groups showed the lowest survival rate of 62.6±9.8% compared to the

  2. Genetic studies on sex determination and colouration in Nile tilapia (Oreochromis niloticus L.)

    Energy Technology Data Exchange (ETDEWEB)

    Karayuecel, I

    1999-05-01

    The present study was undertaken to investigate colour and sex determination mechanisms through the application of androgenesis, gynogenesis and controlled breeding programme with the objective of producing all red males in O. niloticus. The highest yield of androgenetic haploid to pigmentation stage was 24.6{+-}3.5% (relative to controls) with optimal UV irradiation dose of 450JM{sup -2} for 5 minutes. The highest survival rate of diploid androgens was 0.07{+-}0.07% (relative to controls) to yolk sac stage using a heat shock of 42.5 deg. C for 3 minutes 30 seconds applied at 25 minutes after fertilisation. All paternal inheritance of diploid androgenetic tilapia was verified using DNA fingerprinting. The mean recombination frequency of the red skin colour gene in meiotic gynogens was 0.12{+-}0.04. All maternal inheritance of meiotic gynogens was verified using the isozyme locus ADA*. Analyses of sex ratios of meiotic gynogens suggested that male progenies were produced by an epistatic sex determining locus (SDL-2 with two alleles SR and sr) causing female to male sex reversal in the homozygous phase (srsr) but with limited penetrance. A close linkage was found between a sex determining locus (SDL-2) and the red gene. No significant difference was found between colour genotypes (namely homozygous red, heterozygous red and wild type) in terms of total fecundity, ISI (inter spawning interval), egg size and survival rate. Overall mean ISI was 26.3{+-}1.0 days. Mean total fecundity was 1096 eggs. Fecundity varied over successive spawns but this variation did not appear to be related to spawning periodicity. Hormonal and thermal feminization were compared on all YY male progeny of O. niloticus. While similar female percentages of 32.0{+-}5.2 and 33.8{+-}1.5% were produced, significantly higher intersex percentages of 18.5{+-}2.5 and 1.6{+-}0.8 were observed in heat and DES treated groups, respectively. Heat treatment groups showed the lowest survival rate of 62

  3. Temperature dependence of positron trapping by vacancies, loops and voids in molybdenum

    International Nuclear Information System (INIS)

    Bentzon, M.D.; Linderoth, S.; Petersen, K.

    1985-01-01

    The temperature dependence of positron trapping by defects in molybdenum has been studied. By resolving positron lifetime spectra into three components, it has been possible to distinguish the temperature dependence of positron trapping into loops and voids. The results show that the positron trapping rate into voids depends linearly on temperature. The temperature dependence of positron trapping by loops can be interpreted as positrons being trapped by jogs, directly or via the dislocation line. The temperature dependence of positrons trapped by loops is argued mainly to be due to the trapping at the dislocation line, and not to detrapping. The observed temperature dependence of positron annihilation parameters in an electron irradiated sample (below stage III), is explained by competitive positron trapping in interstitial loops at low temperatures

  4. Determine sex ratios of green turtles along the U.S. West Coast through examinations of hormones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A testosterone (T) enzyme-linked immunosorbent assay (ELISA) was validated for use with green turtle plasma in order to determine the sex of juvenile turtles. We...

  5. Sex-specific genetic determinants for arterial stiffness in Dahl salt-sensitive hypertensive rats.

    Science.gov (United States)

    Decano, Julius L; Pasion, Khristine A; Black, Nicole; Giordano, Nicholas J; Herrera, Victoria L; Ruiz-Opazo, Nelson

    2016-01-11

    Arterial stiffness is an independent predictor of cardiovascular outcomes in hypertensive patients including myocardial infarction, fatal stroke, cerebral micro-bleeds which predicts cerebral hemorrhage in hypertensive patients, as well as progression to hypertension in non-hypertensive subjects. The association between arterial stiffness and various cardiovascular outcomes (coronary heart disease, stroke) remains after adjusting for age, sex, blood pressure, body mass index and other known predictors of cardiovascular disease, suggesting that arterial stiffness, measured via carotid-femoral pulse wave velocity, has a better predictive value than each of these factors. Recent evidence shows that arterial stiffening precedes the onset of high blood pressure; however their molecular genetic relationship (s) and sex-specific determinants remain uncertain. We investigated whether distinct or shared genetic determinants might underlie susceptibility to arterial stiffening in male and female Dahl salt-sensitive rats. Thus, we performed a genome-wide scan for quantitative trait loci (QTLs) affecting arterial stiffness in six-week old F2 (Dahl S x R)-intercross male and female rats characterized for abdominal aortic pulse wave velocity and aortic strain by high-resolution ultrasonography. We detected five highly significant QTLs affecting aortic stiffness: two interacting QTLs (AS-m1 on chromosome 4 and AS-m2 on chromosome16, LOD 8.8) in males and two distinct interacting QTLs (AS-f1 on chromosome 9 and AS-f2 on chromosome11, LOD 8.9) in females affecting pulse wave velocity. One QTL (AS-1 on chromosome 3, LOD 4.3) was found to influence aortic strain in a sex-independent manner. None of these arterial stiffness QTLs co-localized with previously reported blood pressure QTLs detected in equivalent genetic intercrosses. These data reveal sex-specific genetic determinants for aortic pulse wave velocity and suggest distinct polygenic susceptibility for arterial stiffness and

  6. Anomalous Temperature Dependence of the Band Gap in Black Phosphorus

    OpenAIRE

    Villegas, Cesar E. P.; Rocha, A. R.; Marini, Andrea

    2016-01-01

    Black Phosphorus (BP) has gained renewed attention due to its singular anisotropic electronic and optical properties that might be exploited for a wide range of technological applications. In this respect, the thermal properties are particularly important both to predict its room temperature operation and to determine its thermoelectric potential. From this point of view, one of the most spectacular and poorly understood phenomena is, indeed, the BP temperature-induced band-gap opening: when ...

  7. A fully automated temperature-dependent resistance measurement setup using van der Pauw method

    Science.gov (United States)

    Pandey, Shivendra Kumar; Manivannan, Anbarasu

    2018-03-01

    The van der Pauw (VDP) method is widely used to identify the resistance of planar homogeneous samples with four contacts placed on its periphery. We have developed a fully automated thin film resistance measurement setup using the VDP method with the capability of precisely measuring a wide range of thin film resistances from few mΩ up to 10 GΩ under controlled temperatures from room-temperature up to 600 °C. The setup utilizes a robust, custom-designed switching network board (SNB) for measuring current-voltage characteristics automatically at four different source-measure configurations based on the VDP method. Moreover, SNB is connected with low noise shielded coaxial cables that reduce the effect of leakage current as well as the capacitance in the circuit thereby enhancing the accuracy of measurement. In order to enable precise and accurate resistance measurement of the sample, wide range of sourcing currents/voltages are pre-determined with the capability of auto-tuning for ˜12 orders of variation in the resistances. Furthermore, the setup has been calibrated with standard samples and also employed to investigate temperature dependent resistance (few Ω-10 GΩ) measurements for various chalcogenide based phase change thin films (Ge2Sb2Te5, Ag5In5Sb60Te30, and In3SbTe2). This setup would be highly helpful for measurement of temperature-dependent resistance of wide range of materials, i.e., metals, semiconductors, and insulators illuminating information about structural change upon temperature as reflected by change in resistances, which are useful for numerous applications.

  8. Temperature-dependent inhibition of opportunistic Vibrio pathogens by native coral commensal bacteria.

    Science.gov (United States)

    Frydenborg, Beck R; Krediet, Cory J; Teplitski, Max; Ritchie, Kim B

    2014-02-01

    Bacteria living within the surface mucus layer of corals compete for nutrients and space. A number of stresses affect the outcome of this competition. The interactions between native microorganisms and opportunistic pathogens largely determine the coral holobiont's overall health and fitness. In this study, we tested the hypothesis that commensal bacteria isolated from the mucus layer of a healthy elkhorn coral, Acropora palmata, are capable of inhibition of opportunistic pathogens, Vibrio shiloi AK1 and Vibrio coralliilyticus. These vibrios are known to cause disease in corals and their virulence is temperature dependent. Elevated temperature (30 °C) increased the cell numbers of one commensal and both Vibrio pathogens in monocultures. We further tested the hypothesis that elevated temperature favors pathogenic organisms by simultaneously increasing the fitness of vibrios and decreasing the fitness of commensals by measuring growth of each species within a co-culture over the course of 1 week. In competition experiments between vibrios and commensals, the proportion of Vibrio spp. increased significantly under elevated temperature. We finished by investigating several temperature-dependent mechanisms that could influence co-culture differences via changes in competitive fitness. The ability of Vibrio spp. to utilize glycoproteins found in A. palmata mucus increased or remained stable when exposed to elevated temperature, while commensals' tended to decrease utilization. In both vibrios and commensals, protease activity increased at 30 °C, while chiA expression increased under elevated temperatures for Vibrio spp. These results provide insight into potential mechanisms through which elevated temperature may select for pathogenic bacterial dominance and lead to disease or a decrease in coral fitness.

  9. Temperature dependent current transport of Pd/ZnO nanowire Schottky diodes

    Science.gov (United States)

    Gayen, R. N.; Bhattacharyya, S. R.; Jana, P.

    2014-09-01

    Zinc oxide (ZnO) nanowire based Schottky barrier diodes are fabricated by depositing Pd metal contact on top of vertically well-aligned ZnO nanowire arrays. A vertical array of ZnO nanowires on indium tin oxide (ITO) coated glass substrates is synthesized by hybrid wet chemical route. Scanning electron microscopy (SEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) measurement confirm the formation of stoichiometric well-aligned hexagonal (h-ZnO) nanowire arrays with wurtzite structure. Temperature dependent current-voltage (I-V) measurements on palladium-ZnO (Pd/ZnO) nanowire Schottky junctions in the temperature range 303-383 K exhibit excellent rectifying character. From these nonlinear I-V plots, different electrical parameters of diode-like reverse saturation current, barrier height and ideality factor are determined as a function of temperature assuming pure thermionic emission model. The ideality factor is found to decrease while the barrier height increases with the increase in temperature. The series resistance values calculated from Cheung’s functions also show temperature dependency. Such behavior can be attributed to the presence of defects that traps carriers, and barrier height inhomogeneity at the interface of the barrier junction. After barrier height inhomogeneity correction, considering a Gaussian distributed barrier height fluctuation across the Pd/ZnO interface, the estimated values of mean barrier height and modified Richardson constant are more closely matched to the theoretically predicted value for Pd/ZnO Schottky barrier diodes. The variation of density of interface states as a function of interface state energy is also calculated.

  10. Bombyx mori histone methyltransferase BmAsh2 is essential for silkworm piRNA-mediated sex determination.

    Science.gov (United States)

    Li, Zhiqian; You, Lang; Yan, Dong; James, Anthony A; Huang, Yongping; Tan, Anjiang

    2018-02-01

    Sex determination is a hierarchically-regulated process with high diversity in different organisms including insects. The W chromosome-derived Fem piRNA has been identified as the primary sex determination factor in the lepidopteran insect, Bombyx mori, revealing a distinctive piRNA-mediated sex determination pathway. However, the comprehensive mechanism of silkworm sex determination is still poorly understood. We show here that the silkworm PIWI protein BmSiwi, but not BmAgo3, is essential for silkworm sex determination. CRISPR/Cas9-mediated depletion of BmSiwi results in developmental arrest in oogenesis and partial female sexual reversal, while BmAgo3 depletion only affects oogenesis. We identify three histone methyltransferases (HMTs) that are significantly down-regulated in BmSiwi mutant moths. Disruption one of these, BmAsh2, causes dysregulation of piRNAs and transposable elements (TEs), supporting a role for it in the piRNA signaling pathway. More importantly, we find that BmAsh2 mutagenesis results in oogenesis arrest and partial female-to-male sexual reversal as well as dysregulation of the sex determination genes, Bmdsx and BmMasc. Mutagenesis of other two HMTs, BmSETD2 and BmEggless, does not affect piRNA-mediated sex determination. Histological analysis and immunoprecipitation results support a functional interaction between the BmAsh2 and BmSiwi proteins. Our data provide the first evidence that the HMT, BmAsh2, plays key roles in silkworm piRNA-mediated sex determination.

  11. Bombyx mori histone methyltransferase BmAsh2 is essential for silkworm piRNA-mediated sex determination.

    Directory of Open Access Journals (Sweden)

    Zhiqian Li

    2018-02-01

    Full Text Available Sex determination is a hierarchically-regulated process with high diversity in different organisms including insects. The W chromosome-derived Fem piRNA has been identified as the primary sex determination factor in the lepidopteran insect, Bombyx mori, revealing a distinctive piRNA-mediated sex determination pathway. However, the comprehensive mechanism of silkworm sex determination is still poorly understood. We show here that the silkworm PIWI protein BmSiwi, but not BmAgo3, is essential for silkworm sex determination. CRISPR/Cas9-mediated depletion of BmSiwi results in developmental arrest in oogenesis and partial female sexual reversal, while BmAgo3 depletion only affects oogenesis. We identify three histone methyltransferases (HMTs that are significantly down-regulated in BmSiwi mutant moths. Disruption one of these, BmAsh2, causes dysregulation of piRNAs and transposable elements (TEs, supporting a role for it in the piRNA signaling pathway. More importantly, we find that BmAsh2 mutagenesis results in oogenesis arrest and partial female-to-male sexual reversal as well as dysregulation of the sex determination genes, Bmdsx and BmMasc. Mutagenesis of other two HMTs, BmSETD2 and BmEggless, does not affect piRNA-mediated sex determination. Histological analysis and immunoprecipitation results support a functional interaction between the BmAsh2 and BmSiwi proteins. Our data provide the first evidence that the HMT, BmAsh2, plays key roles in silkworm piRNA-mediated sex determination.

  12. Mandibular ramus: A predictor for sex determination - A digital radiographic study

    Directory of Open Access Journals (Sweden)

    Kotya Naik Maloth

    2017-01-01

    Full Text Available Aim: To evaluate mandibular ramus linear measurements on digital panoramic radiographs and to assess the usefulness of mandibular ramus in sex determination. Material and Methods: A retrospective study was conducted on 100 patients (50 males and 50 females using digital panoramic radiographs of Khammam population with age ranging from 20 to 50 years. Standard digital panoramic radiographs were taken without any errors by Sirona, ORTHOPHOS XG 5 machine. The following five mandibular linear measurements were performed in cm such as upper ramus breadth, lower ramus breadth, condylar ramus height, projective ramus height, and coronoid ramus height. The obtained data were analyzed with the software SPSS 13.0 for statistical analysis using discriminate methods. Results: In the present study, all the linear measurements of mandibular ramus on digital panoramic radiographs showed a statistically significant difference between the genders. Conclusion: We conclude that the use of mandibular ramus is recommended as an aid for sex determination in forensic science due to their unique feature of sexual dimorphism.

  13. Sex Determination Using Inion-Opistocranium-Asterion (IOA Triangle in Nigerians’ Skulls

    Directory of Open Access Journals (Sweden)

    C. N. Orish

    2014-01-01

    Full Text Available Background. Determination of sex is an important concern to the forensic anthropologists as it is critical for individual identification. This study has investigated the existence of sexual dimorphism in the dimensions and the area of the IOA triangle. Methods. A total of 100 adult dry skulls, (78 males; 22 females from departments of anatomy in Nigerian universities were used for this study. Automatic digital calliper was used for the measurement. Coefficient of variation, correlation, linear regression, percentiles, and sexual dimorphism ratio were computed from the IOA triangle measurements. The IOA triangle area was compared between sexes. Results. The male parameters were significantly (P<0.05 higher than female parameters. The left opistocranium-asterion length was 71.09±0.56 and 61.68±3.35 mm and the right opistocranium-asterion length was 69.73±0.49 and 60.92±2.10 mm for male and female, respectively. A total area of IOA triangle of 1938.88 mm2 and 1305.68 mm2 for male and female, respectively, was calculated. The left IOA indices were 46.42% and 37.40% in males and females, respectively, while the right IOA indices for males and females were 47.19% and 38.87%, respectively. Conclusion. The anthropometry of inion-opistocranium-asterion IOA triangle can be a guide in gender determination of unknown individuals.

  14. Label-free detection of sex determining region Y (SRY) via capacitive biosensor

    KAUST Repository

    Sivashankar, Shilpa

    2016-10-20

    In this work, we present for the first time, the use of a simple fractal capacitive biosensor for the quantification and detection of sex-determining region Y (SRY) genes. This section of genetic code, which is found on the Y chromosome, finds importance for study as it causes fetuses to develop characteristics of male sex-like gonads when a mutation occurs. It is also an important genetic code in men, and disorders involving the SRY gene can cause infertility and sexual malfunction that lead to a variety of gene mutational disorders. We have therefore designed silicon-based, label-free fractal capacitive biosensors to quantify various proteins and genes. We take advantage of a good dielectric material, Parylene C for enhancing the performance of the sensors. We have integrated these sensors with a simple microchannel for easy handling of fluids on the detection area. The read-out value of an Agilent LCR meter used to measure capacitance of the sensor at a frequency of 1 MHz determined gene specificity and gene quantification. These data revealed that the capacitance measurement of the capacitive biosensor for the SRY gene depended on both the target and the concentration of DNA. The experimental outcomes in the present study can be used to detect DNA and its variations in crucial fields that have a great impact on our daily lives, such as clinical and veterinary diagnostics, industrial and environmental testing and forensic sciences.

  15. Temperature dependence of lattice parameters of alpha-zirconium

    International Nuclear Information System (INIS)

    Versaci, R.A.; Ipohorski, M.

    1991-01-01

    This work presents a brief review of X-ray and thermal expansion determination of lattice parameters for α-Zirconium. Data reported by different authors cover almost all the field of existence of the hexagonal phase of Zirconium, from temperatures as low as 4.2 K up to about 1130 K, near the α→β transformation temperature. Polynomial expressions based on a least squares fitting of experimental data are also presented. The expressions obtained by Goldak et al. are considered to be the most complete. The influence of impurities on the lattice parameters is also discussed. (Author) [es

  16. Mapping and validation of the major sex-determining region in Nile tilapia (Oreochromis niloticus L. Using RAD sequencing.

    Directory of Open Access Journals (Sweden)

    Christos Palaiokostas

    Full Text Available Sex in Oreochromis niloticus (Nile tilapia is principally determined by an XX/XY locus but other genetic and environmental factors also influence sex ratio. Restriction Associated DNA (RAD sequencing was used in two families derived from crossing XY males with females from an isogenic clonal line, in order to identify Single Nucleotide Polymorphisms (SNPs and map the sex-determining region(s. We constructed a linkage map with 3,802 SNPs, which corresponded to 3,280 informative markers, and identified a major sex-determining region on linkage group 1, explaining nearly 96% of the phenotypic variance. This sex-determining region was mapped in a 2 cM interval, corresponding to approximately 1.2 Mb in the O. niloticus draft genome. In order to validate this, a diverse family (4 families; 96 individuals in total and population (40 broodstock individuals test panel were genotyped for five of the SNPs showing the highest association with phenotypic sex. From the expanded data set, SNPs Oni23063 and Oni28137 showed the highest association, which persisted both in the case of family and population data. Across the entire dataset all females were found to be homozygous for these two SNPs. Males were heterozygous, with the exception of five individuals in the population and two in the family dataset. These fish possessed the homozygous genotype expected of females. Progeny sex ratios (over 95% females from two of the males with the "female" genotype indicated that they were neomales (XX males. Sex reversal induced by elevated temperature during sexual differentiation also resulted in phenotypic males with the "female" genotype. This study narrows down the region containing the main sex-determining locus, and provides genetic markers tightly linked to this locus, with an association that persisted across the population. These markers will be of use in refining the production of genetically male O. niloticus for aquaculture.

  17. Experimental investigation of temperature dependence of the magnetic susceptibility (T) of manganites La1-xAxMnO3

    International Nuclear Information System (INIS)

    Salakhitdinova, M.; Kuvandikov, O.; Shakarov, Kh.; Shodiev, Z.

    2007-01-01

    Full text: he interest to lanthanoid manganites is based that enormous magnetoresistance is found in them and this materials are capable to test diverse structural and magnetic phase transformations. The work is devoted to experimental investigation of temperature dependence of the magnetic susceptibility (T) of manganites La 1-x A x MnO 3 which doped with Ag, K, Sr metals in wide temperature interval 50-8500 C, as well as to determination of their magnetic characteristics from this dependence. The dependence (T) was measured by the Faraday method with high-temperature magnetic pendulum balance in the atmosphere of refined helium. Maximal relative error of the measurements did not exceed 3 %. The analysis of experimental (T) dependence of investigated manganites has shown that the rise of stoichiometric rate of doped metals the temperature dependence of magnetic susceptibility of manganites monotonously is decreased. (authors)

  18. An Overview of Age, Sex and Race Determination from Teeth and Skull

    Directory of Open Access Journals (Sweden)

    Manas Gupta

    2015-01-01

    Full Text Available Background : Forensic dentistry represents the overlap between the dental and legal professions. Throughout this century, odontological examinations have been a critical determinant in the search for identity of individual remains. Dental maturity has played an important role in estimating the chronological age of individuals. Age estimation is a sub-discipline of the forensic sciences and should be an important part of every identification process, especially when information relating to the deceased is unavailable. Forensic dentist helps in identification of deceased victims by age, sex and race determination from teeth and skull. Since the scope of forensic odontology is very broad and challenging, dental surgeons trained in forensic odontology can make unique contributions in the administration of justice, which is the key note of democracy.

  19. Temperature dependence of poly(lactic acid) mechanical properties

    DEFF Research Database (Denmark)

    Zhou, Chengbo; Guo, Huilong; Li, Jingqing

    2016-01-01

    The mechanical properties of polymers are not only determined by their structures, but also related to the temperature field in which they are located. The yield behaviors, Young's modulus and structures of injection-molded poly(lactic acid) (PLA) samples after annealing at different temperatures....... The crystallinity increases with increasing annealing temperature and a' form crystal is formed when the annealing temperature is higher than 100 oC. The stretched samples with low crystallinity show the first yield at draw temperatures below the glass transition temperature (Tg) and the second yield above Tg....... For the samples annealed between 80 and 120 oC, a peculiar double yield appears when stretched within 50–60 oC and only the first or the second yield can be found at the lower and higher draw temperatures. The yield strain and yield stress together with Young's modulus were obtained and discussed in terms...

  20. Temperature dependent measurement of internal damping of austenitic stainless steels

    Directory of Open Access Journals (Sweden)

    Oravcová Monika

    2018-01-01

    Full Text Available This article is aimed on the analysis of the internal damping changes of austenitic stainless steels AISI 304, AISI 316L and AISI 316Ti depending from temperature. In experimental measurements only resonance method was used which is based on continuous excitation of oscillations of the specimens and the whole apparatus vibrates at the frequency near to the resonance. Microplastic processes and dissipation of energy within the metals are evaluated and investigated by internal damping measurements. Damping capacity of materials is closely tied to the presence of defects including second phase particles and voids. By measuring the energy dissipation in the material, we can determine the elastic characteristics, Youngs modulus, the level of stress relaxation and many other.

  1. Temperature dependent fission product removal efficiency due to pool scrubbing

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Shunsuke, E-mail: suchida@iae.or.jp [Institute of Applied Energy, 1-14-2, Nishi-Shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Itoh, Ayumi; Naitoh, Masanori; Okada, Hidetoshi; Suzuki, Hiroyuki [Institute of Applied Energy, 1-14-2, Nishi-Shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Hanamoto, Yukio [KAKEN, Inc., 1044, Hori-machi, Mito 310-0903 (Japan); Osakabe, Masahiro [Tokyo University of Marine Science & Technology, Koutou-ku, Tokyo 135-8533 (Japan); Fujikawa, Masahiro [Japan Broadcasting Corporation, 2-2-1, Jinnan, Shibuya-ku, Tokyo 150-8001 (Japan)

    2016-03-15

    Highlights: • Pool temperature effects on the FP removal were not clearly concluded in the previous publications. • It was confirmed that the removal efficiency decreased with temperature around the boiling point. • A modified empirical formula for FP removal was proposed as a function of sub-cooling temperature. • DF could be predicted with an accuracy within a factor of 2 with the proposed formula. - Abstract: The wet-well of boiling water reactors plays important roles not only to suppress the pressure in the primary containment vessel due to steam scrubbing effects during severe accidents but also to mitigate release of radioactive fission products (FP), aerosols and particulates, into the environment. The effects of steam scrubbing in the wet-well on FP removal have been well studied and reported by changing major parameters determining the removal efficiencies, e.g., aerosol diameters, submergence (depth of scrubbing nozzles) and steam/non-condensable gas volume fraction. Unfortunately, the effects of pool temperature on the FP removal were not clearly concluded in the previous publications, though it would be easily expected that boiling in the pool resulted in reduced aerosol removal efficiency. In order to determine the temperature effects on FP removal efficiency, amounts of cesium in aerosols released from scrubbing pool were measured by changing pool temperature in mini and medium scale scrubbing experiments, and then, it was confirmed that the removal efficiency clearly decreased with temperature around the boiling point. Then, a modified empirical formula to express the FP removal around the boiling point temperature was proposed as a function of sub-cooling temperature by applying the effective steam volume fraction, which was designated as the volume ratio of condensed steam in the pool versus the sum of input steam and non-condensable gas. By comparing the measured removal efficiency with the calculated, it was validated that the

  2. Temperature dependent fission product removal efficiency due to pool scrubbing

    International Nuclear Information System (INIS)

    Uchida, Shunsuke; Itoh, Ayumi; Naitoh, Masanori; Okada, Hidetoshi; Suzuki, Hiroyuki; Hanamoto, Yukio; Osakabe, Masahiro; Fujikawa, Masahiro

    2016-01-01

    Highlights: • Pool temperature effects on the FP removal were not clearly concluded in the previous publications. • It was confirmed that the removal efficiency decreased with temperature around the boiling point. • A modified empirical formula for FP removal was proposed as a function of sub-cooling temperature. • DF could be predicted with an accuracy within a factor of 2 with the proposed formula. - Abstract: The wet-well of boiling water reactors plays important roles not only to suppress the pressure in the primary containment vessel due to steam scrubbing effects during severe accidents but also to mitigate release of radioactive fission products (FP), aerosols and particulates, into the environment. The effects of steam scrubbing in the wet-well on FP removal have been well studied and reported by changing major parameters determining the removal efficiencies, e.g., aerosol diameters, submergence (depth of scrubbing nozzles) and steam/non-condensable gas volume fraction. Unfortunately, the effects of pool temperature on the FP removal were not clearly concluded in the previous publications, though it would be easily expected that boiling in the pool resulted in reduced aerosol removal efficiency. In order to determine the temperature effects on FP removal efficiency, amounts of cesium in aerosols released from scrubbing pool were measured by changing pool temperature in mini and medium scale scrubbing experiments, and then, it was confirmed that the removal efficiency clearly decreased with temperature around the boiling point. Then, a modified empirical formula to express the FP removal around the boiling point temperature was proposed as a function of sub-cooling temperature by applying the effective steam volume fraction, which was designated as the volume ratio of condensed steam in the pool versus the sum of input steam and non-condensable gas. By comparing the measured removal efficiency with the calculated, it was validated that the

  3. Sex determination in Turdus amaurochalinus (Passeriformes: Muscicapidae: morphometrical analysis supported by CHD gene

    Directory of Open Access Journals (Sweden)

    Katyucha Von Kossel de Andrade Silva

    2011-06-01

    Full Text Available Sex determination is important for conservation and population studies, particularly for reproduction programs of threatened species and behavioural ecology. Turdus amaurochalinus, Creamy-bellied Thrush, only exhibits sexual dimorphism during the breeding season, when males are considered to show intense yellow bills, and females and immature males show dark brown bills. The objectives of this study were: 1 to determine the sex of individuals using genetic techniques, and 2 to test the hypothesis that sex dimorphism can be detected by morphometry. This study was carried out at Parque Nacional da Restinga de Jurubatiba, a preserved area located on the North coast of Rio de Janeiro State. The birds were captured using ornithological nets, singly marked with metal rings, weighed, measured and had blood samples collected before being released. The sex of 42 T. amaurochalinus individuals was determined using the CHD gene marker. A total of 20 males and 22 females were identified from June to August, with peak capture frequency in June. Turdus amaurochalinus females and males differed significantly in morphometrical measures. The most important traits to distinguish males from females were wing length (Student t-test=4.34, df=40, p=0.0001 and weight (Student t-test=2.08,df=40, p=0.044: females were heavier and had significantly shorter wing length than males. Females and males were correctly classified in 86% and 75% of cases, respectively, using Discriminant Analysis. The molecular analysis was the most secure method for sex determination in the studied species. Rev. Biol. Trop. 59 (2: 789- 794. Epub 2011 June 01.La determinación del sexo es importante para la conservación y los estudios poblacionales. Turdus amaurochalinus no presenta aparente dimorfismo sexual. El objetivo de este estudio fue determinar el sexo a través de una técnica genética, mediante el uso del marcador del gen CHD y se puso a prueba la hipótesis de que el dimorfismo

  4. Temperature dependence on shock response of stainless steel

    International Nuclear Information System (INIS)

    Gu Zhuowei; Jin Xiaogang

    1998-01-01

    Free surface velocity measurements were reported for HR-2(Cr-Ni-Mn-N) stainless steel, initially heated to 300K∼1000K and shock-compressed to about 8GPa. The corresponding spall strength σ f and Hugoniot elastic limit σ HEL were determined from the wave profiles. It is demonstrated that σ f and σ HEL decrease linearly with increasing temperature T in the range from 300K to 806K, i.e., σ f =5.63-4.32x10 -3 T and σ HEL =2.08-1.54x10 -3 T, and in the range of 806K∼980K, σ HEL increases from 0.84GPa at 806K to 0.93GPa at 980K, σ f has a negligible increase to 2.15GPa from 2.14GPa. Primary TEM test on recovery samples identified the existence of intermatallic compound Ni 3 Ti in the sample of 980K

  5. Frequency and temperature dependence of high damping elastomers

    International Nuclear Information System (INIS)

    Kulak, R.F.; Hughes, T.H.

    1993-01-01

    High damping steel-laminated elastomeric seismic isolation bearings are one of the preferred devices for isolating large buildings and structures. In the US, the current reference design for the Advanced Liquid Metal Reactor (ALMR) uses laminated bearings for seismic isolation. These bearings are constructed from alternating layers of high damping rubber and steel plates. They are typically designed for shear strains between 50 and 100% and are expected to sustain two to three times these levels for beyond design basis loading conditions. Elastomeric bearings are currently designed to provide a system frequency between 0.4 and 0.8 Hz and expected to operate between -20 and 40 degrees Centigrade. To assure proper performance of isolation bearings, it is necessary to characterize the elastomer's response under expected variations of frequency and temperature. The dynamic response of the elastomer must be characterized within the frequency range that spans the bearing acceptance test frequency, which may be as low as 0.005 Hz, and the design frequency. Similarly, the variation in mechanical characteristics of the elastomer must be determined over the design temperature range, which is between -20 and 40 degrees Centigrade. This paper reports on (1) the capabilities of a testing facility at ANL for testing candidate elastomers, (2) the variation with frequency and temperature of the stiffness and damping of one candidate elastomer, and (3) the effect of these variations on bearing acceptance testing criteria and on the choice of bearing design values for stiffness and damping

  6. Temperature Dependences on Various Types of Photovoltaic (PV) Panel

    International Nuclear Information System (INIS)

    Audwinto, I A; Leong, C S; Sopian, K; Zaidi, S H

    2015-01-01

    Temperature is one of the key roles in PV technology performance, since with the increases of temperature the open-circuit voltage will drop accordingly so do the electrical efficiency and power output generation. Different types of Photovoltaic (PV) panels- silicon solar panels and thin film solar panels; mono-crystalline, poly-crystalline, CIS, CIGS, CdTe, back-contact, and bi-facial solar panel under 40°C to 70°C approximately with 5°C interval have been comparatively analyzed their actual performances with uniformly distribution of light illumination from tungsten halogen light source, ±500W/m 2 . DC-Electronic Load and Data Logger devices with “Lab View” data program interface were used to collect all the necessary parameters in this study. Time needed to achieve a certain degree of temperature was recorded. Generally, each of the panels needed 15 minutes to 20 minutes to reach 70°C. Halogen based light source is not compatible in short wave-length in response to thin-film solar cell. Within this period of times, all the panels are facing a performance loss up to 15%. Other parameters; P max , V max , I max , V oc , I sc , R serries , R shunt , Fillfactor were collected as study cases. Our study is important in determining Photovoltaic type selection and system design as for study or industrial needed under different temperature condition. (paper)

  7. Temperature dependent elasticity and damping in dehydrated sandstone

    Science.gov (United States)

    Darling, T. W.; Struble, W.

    2013-12-01

    Work reported previously at this conference, outlining our observation of anomalously large elastic softening and damping in dehydrated Berea sandstone at elevated temperatures, has been analysed to study shear and compressional effects separately. Modeling of the sample using COMSOL software was necessary to identify modes, as the vibration spectrum of the sample is poorly approximated by a uniform isotropic solid. The first torsional mode of our evacuated, dry, core softens at nearly twice the rate of Young's modulus modes (bending and compressional) and is also damped nearly twice as strongly as temperature increases. We consider two possible models for explaining this behavior, based on the assumption that the mechanical properties of the sandstone are dominated by the framework of quartz grains and polycrystalline cementation, neglecting initially the effects of clay and feldspar inclusions. The 20cm x 2.54cm diameter core is dry such that the pressure of water vapor in the experiment chamber is below 1e-6 Torr at 70C, suggesting that surface water beyond a small number of monolayers is negligible. Our models consider (1) enhanced sliding of grain boundaries in the cementation at elevated temperature and reduced internal water content, and (2) strain microcracking of the cementatioin at low water content due to anisotropic expansion in the quartz grains. In model (1) interfaces parallel to polyhedral grain surfaces were placed in the cement bonds and assigned frictional properties. Model (2) has not yet been implemented. The overall elasticity of a 3-D several-grain model network was determined by modeling quasistatic loading and measuring displacements. Initial results with a small number of grains/bonds suggests that only the first model provides softening and damping for all the modes, however the details of the effects of defect motioin at individual interfaces as the source for the frictional properties is still being evaluated. Nonlinear effects are

  8. Temperature-dependent phenotypic variation of Campylobacter jejuni lipooligosaccharides

    LENUS (Irish Health Repository)

    Semchenko, Evgeny A

    2010-11-30

    Abstract Background Campylobacter jejuni is a major bacterial cause of food-borne enteritis, and its lipooligosaccharide (LOS) plays an initiating role in the development of the autoimmune neuropathy, Guillain-Barré syndrome, by induction of anti-neural cross-reactive antibodies through ganglioside molecular mimicry. Results Herein we describe the existence and heterogeneity of multiple LOS forms in C. jejuni strains of human and chicken origin grown at 37°C and 42°C, respectively, as determined on sodium dodecyl sulphate-polyacrylamide electrophoresis gels with carbohydrate-specific silver staining and blotting with anti-ganglioside ligands, and confirmed by nuclear magnetic resonance (NMR) spectroscopy. The C. jejuni NCTC 11168 original isolate (11168-O) was compared to its genome-sequenced variant (11168-GS), and both were found to have a lower-Mr LOS form, which was different in size and structure to the previously characterized higher-Mr form bearing GM1 mimicry. The lower-Mr form production was found to be dependent on the growth temperature as the production of this form increased from ~5%, observed at 37°C to ~35% at 42°C. The structure of the lower-Mr form contained a β-D-Gal-(1→3)-β-D-GalNAc disaccharide moiety which is consistent with the termini of the GM1, asialo-GM1, GD1, GT1 and GQ1 gangliosides, however, it did not display GM1 mimicry as assessed in blotting studies but was shown in NMR to resemble asialo-GM1. The production of multiple LOS forms and lack of GM1 mimicry was not a result of phase variation in the genes tested of NCTC 11168 and was also observed in most of the human and chicken isolates of C. jejuni tested. Conclusion The presence of differing amounts of LOS forms at 37 and 42°C, and the variety of forms observed in different strains, indicate that LOS form variation may play a role in an adaptive mechanism or a stress response of the bacterium during the colonization of different hosts.

  9. Sex Determination and Polyploid Gigantism in the Dwarf Surfclam (Mulinia Lateralis Say)

    Science.gov (United States)

    Guo, X.; Allen-Jr., S. K.

    1994-01-01

    Mulinia lateralis, the dwarf surfclam, is a suitable model for bivalve genetics because it is hardy and has a short generation time. In this study, gynogenetic and triploid. M. lateralis were successfully induced. For gynogenesis, eggs were fertilized with sperm irradiated with ultraviolet light and subsequently treated with cytochalasin B to block the release of the second polar body (PB2). Triploidy was induced by blocking PB2 in normally fertilized eggs. The survival of gynogenetic diploids was very low, only 0.7% to 8 days post-fertilization (PF), compared with 15.2% in the triploid groups and 27.5% in the normal diploid control. Larvae in all groups metamorphosed at 8-10 days PF, and there was no significant post-larval mortality. At sexual maturation (2-3 months PF), all gynogenetic diploids were female, and there was no significant difference (P > 0.05) in sex ratio between diploids and triploids. These results suggested that the dwarf surfclam may have an XX-female, XY-male sex determination with Y-domination. Compared with diploids, triploids had a relative fecundity of 59% for females and 80% for males. Eggs produced by triploid females were 53% larger (P 0.33) different from normal diploid females, suggesting that inbreeding depression was minimal in meiosis II gynogens. Triploid clams were significantly larger (P gigantism due to the increased cell volume and a lack of cell-number compensation. PMID:7896101

  10. Temperature dependent magnetic properties of the GaAs substrate of spin-LEDs

    International Nuclear Information System (INIS)

    Ney, A; Harris, J S Jr; Parkin, S S P

    2006-01-01

    The temperature dependence of the magnetization of a light emitting diode having a ferromagnetic contact (spin-LED) is measured from 2 to 300 K in magnetic fields from 30 to 70 kOe and it is found that it originates from the GaAs substrate. The magnetization of GaAs comprises a van Vleck-type paramagnetic contribution to the susceptibility which scales inversely with the band gap of the semiconductor. Thus, the temperature dependence of the band gap of GaAs accounts for the non-linear temperature dependent magnetic susceptibility of GaAs and thus, at large magnetic fields, for the spin-LED

  11. Temperature-dependent gate-swing hysteresis of pentacene thin film transistors

    Directory of Open Access Journals (Sweden)

    Yow-Jon Lin

    2014-10-01

    Full Text Available The temperature-dependent hysteresis-type transfer characteristics of pentacene-based organic thin film transistors (OTFTs were researched. The temperature-dependent transfer characteristics exhibit hopping conduction behavior. The fitting data for the temperature-dependent off-to-on and on-to-off transfer characteristics of OTFTs demonstrate that the hopping distance (ah and the barrier height for hopping (qϕt control the carrier flow, resulting in the hysteresis-type transfer characteristics of OTFTs. The hopping model gives an explanation of the gate-swing hysteresis and the roles played by qϕt and ah.

  12. Thermal expansion, anharmonicity and temperature-dependent Raman spectra of single- and few-layer MoSe₂ and WSe₂.

    Science.gov (United States)

    Late, Dattatray J; Shirodkar, Sharmila N; Waghmare, Umesh V; Dravid, Vinayak P; Rao, C N R

    2014-06-06

    We report the temperature-dependent Raman spectra of single- and few-layer MoSe2 and WSe2 in the range 77-700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high-resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A(2)(2u) mode is larger than that of the A(1g) mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single-layer MoS2 and of the G band of graphene. The temperature coefficients of the two modes in single-layer MoSe2 are larger than those of the same modes in single-layer WSe2. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS2 and MoSe2 within a quasi-harmonic approximation, with inputs from first-principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman-active mode A(1g) in MoS2 and MoSe2 arises essentially from the difference in their strain-phonon coupling. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The behavioural consequences of sex reversal in dragons

    Science.gov (United States)

    Li, Hong; Holleley, Clare E.; Elphick, Melanie; Georges, Arthur

    2016-01-01

    Sex differences in morphology, physiology, and behaviour are caused by sex-linked genes, as well as by circulating sex-steroid levels. Thus, a shift from genotypic to environmental sex determination may create an organism that exhibits a mixture of male-like and female-like traits. We studied a lizard species (Central Bearded Dragon, Pogona vitticeps), in which the high-temperature incubation of eggs transforms genetically male individuals into functional females. Although they are reproductively female, sex-reversed dragons (individuals with ZZ genotype reversed to female phenotype) resemble genetic males rather than females in morphology (relative tail length), general behaviour (boldness and activity level), and thermoregulatory tactics. Indeed, sex-reversed ‘females’ are more male-like in some behavioural traits than are genetic males. This novel phenotype may impose strong selection on the frequency of sex reversal within natural populations, facilitating rapid shifts in sex-determining systems. A single period of high incubation temperatures (generating thermally induced sex reversal) can produce functionally female individuals with male-like (or novel) traits that enhance individual fitness, allowing the new temperature-dependent sex-determining system to rapidly replace the previous genetically based one.

  14. The fate of W chromosomes in hybrids between wild silkmoths, Samia cynthia ssp.: no role in sex determination and reproduction.

    Science.gov (United States)

    Yoshido, A; Marec, F; Sahara, K

    2016-05-01

    Moths and butterflies (Lepidoptera) have sex chromosome systems with female heterogamety (WZ/ZZ or derived variants). The maternally inherited W chromosome is known to determine female sex in the silkworm, Bombyx mori. However, little is known about the role of W chromosome in other lepidopteran species. Here we describe two forms of the W chromosome, W and neo-W, that are transmitted to both sexes in offspring of hybrids from reciprocal crosses between subspecies of wild silkmoths, Samia cynthia. We performed crosses between S. c. pryeri (2n=28, WZ/ZZ) and S. c. walkeri (2n=26, neo-Wneo-Z/neo-Zneo-Z) and examined fitness and sex chromosome constitution in their hybrids. The F1 hybrids of both reciprocal crosses had reduced fertility. Fluorescence in situ hybridization revealed not only the expected sex chromosome constitutions in the backcross and F2 hybrids of both sexes but also females without the W (or neo-W) chromosome and males carrying the W (or neo-W) chromosome. Furthermore, crosses between the F2 hybrids revealed no association between the presence or absence of W (or neo-W) chromosome and variations in the hatchability of their eggs. Our results clearly suggest that the W (or neo-W) chromosome of S. cynthia ssp. plays no role in sex determination and reproduction, and thus does not contribute to the formation of reproductive barriers between different subspecies.

  15. Sex Determination in Bees. IV. Genetic Control of Juvenile Hormone Production in MELIPONA QUADRIFASCIATA (Apidae)

    Science.gov (United States)

    Kerr, Warwick Estevam; Akahira, Yukio; Camargo, Conceição A.

    1975-01-01

    Cell number and volume of corpora allata was determined for 8 phases of development, the first prepupal stage to adults 30 days old, in the social Apidae Melipona quadrifasciata. In the second prepupal stage a strong correlation was found between cell number and body weight ( r=0.651**), and cell number and corpora allata volume in prepupal stage (r=0.535*), which indicates that juvenile hormone has a definite role in caste determination in Melipona. The distribution of the volume of corpus allatum suggest a 3:1 segregation between bees with high volume of corpora allata against low and medium volume. This implies that genes xa and xb code for an enzyme that directly participates in juvenile hormone production. It was also concluded that the number of cells in the second prepupal stage is more important than the weight of the prepupa for caste determination. A scheme summarizing the genic control of sex and caste determination in Melipona bees in the prepupal phase is given. PMID:1213273

  16. Sex determination of human mandible using metrical parameters by computed tomography: A prospective radiographic short study

    Directory of Open Access Journals (Sweden)

    Basavaraj N Kallalli

    2016-01-01

    Full Text Available Introduction: Sex determination of unidentified human remains is very important in forensic medicine, medicolegal cases, and forensic anthropology. The mandible is the largest and hardest facial bone that commonly resists postmortem damage and forms an important source of personal identification. Additional studies have demonstrated the applicability of facial reconstruction using three-dimensional computed tomography scan (3D-CT for the purpose of individual identification. Aim: To determine the sex of human mandible using metrical parameters by CT. Materials and Methods: The study included thirty subjects (15 males and 15 females, with age group ranging between 10 and 60 years obtained from the outpatient department of Oral Medicine and Radiology, Narsinhbhai Patel Dental College and Hospital. CT scan was performed on all the subjects, and the data obtained were reconstructed for 3D viewing. After obtaining 3D-CT scan, a total of seven mandibular measurements, i.e., gonial angle (G-angle, ramus length (Ramus-L, minimum ramus breadth and gonion-gnathion length (G-G-L, bigonial breadth, bicondylar breadth (BIC-Br, and coronoid length (CO-L were measured; collected data were analyzed using SPSS statistical analysis program by Student's t-test. Results: The result of the study showed that out of seven parameters, G-angle, Ramus-L, G-G-L, BIC-Br, and CO-L showed a significant statistical difference (P < 0.05, with overall accuracy of 86% for males and 82% for females. Conclusion: Personal identification using mandible by conventional methods has already been proved but with variable efficacies. Advanced imaging modalities can aid in personal identification with much higher accuracy than conventional methods.

  17. Spatial pattern of Baccharis platypoda shrub as determined by sex and life stages

    Science.gov (United States)

    Fonseca, Darliana da Costa; de Oliveira, Marcio Leles Romarco; Pereira, Israel Marinho; Gonzaga, Anne Priscila Dias; de Moura, Cristiane Coelho; Machado, Evandro Luiz Mendonça

    2017-11-01

    Spatial patterns of dioecious species can be determined by their nutritional requirements and intraspecific competition, apart from being a response to environmental heterogeneity. The aim of the study was to evaluate the spatial pattern of populations of a dioecious shrub reporting to sex and reproductive stage patterns of individuals. Sampling was carried out in three areas located in the meridional portion of Serra do Espinhaço, where in individuals of the studied species were mapped. The spatial pattern was determined through O-ring analysis and Ripley's K-function and the distribution of individuals' frequencies was verified through x2 test. Populations in two areas showed an aggregate spatial pattern tending towards random or uniform according to the observed scale. Male and female adults presented an aggregate pattern at smaller scales, while random and uniform patterns were verified above 20 m for individuals of both sexes of the areas A2 and A3. Young individuals presented an aggregate pattern in all areas and spatial independence in relation to adult individuals, especially female plants. The interactions between individuals of both genders presented spatial independence with respect to spatial distribution. Baccharis platypoda showed characteristics in accordance with the spatial distribution of savannic and dioecious species, whereas the population was aggregated tending towards random at greater spatial scales. Young individuals showed an aggregated pattern at different scales compared to adults, without positive association between them. Female and male adult individuals presented similar characteristics, confirming that adult individuals at greater scales are randomly distributed despite their distinct preferences for environments with moisture variation.

  18. MPK-1 ERK Controls Membrane Organization in C. elegans Oogenesis via a Sex-Determination Module

    OpenAIRE

    Arur, Swathi; Ohmachi, Mitsue; Berkseth, Matt; Nayak, Sudhir; Hansen, David; Zarkower, David; Schedl, Tim

    2011-01-01

    Tissues that generate specialized cell-types in a production line must coordinate developmental mechanisms with physiological demand, although how this occurs is largely unknown. In the C. elegans hermaphrodite, the developmental sex-determination cascade specifies gamete sex in the distal germline, while physiological sperm signaling activates MPK-1/ERK in the proximal germline to control plasma membrane biogenesis/organization during oogenesis. We discovered repeated utilization of a self-c...

  19. The fate of W chromosomes in hybrids between wild silkmoths, Samia cynthia ssp.: no role in sex determination and reproduction

    Czech Academy of Sciences Publication Activity Database

    Yoshido, Atsuo; Marec, František; Sahara, K.

    2016-01-01

    Roč. 116, č. 5 (2016), s. 424-433 ISSN 0018-067X R&D Projects: GA ČR(CZ) GA14-22765S Grant - others:The European Union Seventh Framework Programme (FP7/2007-2013)(CZ) 316304 Program:FP7 Institutional support: RVO:60077344 Keywords : hybrids * sex chromosomes * sex determination Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.961, year: 2016

  20. Temperature dependency of external stress corrosion crack propagation of 304 stainless steel

    International Nuclear Information System (INIS)

    Hayashibara, Hitoshi; Mizutani, Yoshihiro; Mayuzumi, Masami; Tani, Jun-ichi

    2010-01-01

    Temperature dependency of external stress corrosion cracking (ESCC) of 304 stainless steel was examined with CT specimens. Maximum ESCC propagation rates appeared in the early phase of ESCC propagation. ESCC propagation rates generally became smaller as testing time advance. Temperature dependency of maximum ESCC propagation rate was analyzed with Arrhenius plot, and apparent activation energy was similar to that of SCC in chloride solutions. Temperature dependency of macroscopic ESCC incubation time was different from that of ESCC propagation rate. Anodic current density of 304 stainless steel was also examined by anodic polarization measurement. Temperature dependency of critical current density of active state in artificial sea water solution of pH=1.3 was similar to that of ESCC propagation rate. (author)

  1. Measurement of Linear Coefficient of Thermal Expansion and Temperature-Dependent Refractive Index Using Interferometric System

    Science.gov (United States)

    Corsetti, James A.; Green, William E.; Ellis, Jonathan D.; Schmidt, Greg R.; Moore, Duncan T.

    2017-01-01

    A system combining an interferometer with an environmental chamber for measuring both coefficient of thermal expansion (CTE) and temperature-dependent refractive index (dn/dT) simultaneously is presented. The operation and measurement results of this instrument are discussed.

  2. Bistable impurity centers in silicon. Temperature dependent characteristics of electro- and thermophysical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Musaeva, L F; Igamberdiev, Kh T; Mamadalimov, A T; Khabibullaev, P K [AS RU, Heat Physics Department, Tashkent (Uzbekistan)

    2003-09-01

    On the basis of experimental data covering temperature dependencies of photoelectric and thermodynamic properties of silicon containing defects the possible physical mechanisms of defect center transformation in the silicon lattice and of phase transitions are discussed. (author)

  3. Bistable impurity centers in silicon. Temperature dependent characteristics of electro- and thermophysical parameters

    International Nuclear Information System (INIS)

    Musaeva, L.F.; Igamberdiev, Kh.T.; Mamadalimov, A.T.; Khabibullaev, P.K.

    2003-01-01

    On the basis of experimental data covering temperature dependencies of photoelectric and thermodynamic properties of silicon containing defects the possible physical mechanisms of defect center transformation in the silicon lattice and of phase transitions are discussed. (author)

  4. Accelerated life testing and temperature dependence of device characteristics in GaAs CHFET devices

    Science.gov (United States)

    Gallegos, M.; Leon, R.; Vu, D. T.; Okuno, J.; Johnson, A. S.

    2002-01-01

    Accelerated life testing of GaAs complementary heterojunction field effect transistors (CHFET) was carried out. Temperature dependence of single and synchronous rectifier CHFET device characteristics were also obtained.

  5. Temperature-Dependent Species Interactions Shape Priority Effects and the Persistence of Unequal Competitors.

    Science.gov (United States)

    Grainger, Tess Nahanni; Rego, Adam Ivan; Gilbert, Benjamin

    2018-02-01

    The order of species arrival at a site can determine the outcome of competitive interactions when early arrivers alter the environment or deplete shared resources. These priority effects are predicted to be stronger at high temperatures, as higher vital rates caused by warming allow early arrivers to more rapidly impact a shared environment. We tested this prediction using a pair of congeneric aphid species that specialize on milkweed plants. We manipulated temperature and arrival order of the two aphid species and measured aphid population dynamics and milkweed survival and defensive traits. We found that warming increased the impact of aphids on the quantity and quality of milkweed, which amplified the importance of priority effects by increasing the competitive exclusion of the inferior competitor when it arrived late. Warming also enhanced interspecific differences in dispersal, which could alter relative arrival times at a regional scale. Our experiment provides a first link between temperature-dependent trophic interactions, priority effects, and dispersal. This study suggests that the indirect and cascading effects of temperature observed here may be important determinants of diversity in the temporally and spatially complex landscapes that characterize ecological communities.

  6. Magnetic behavior of NiCu nanowire arrays: Compositional, geometry and temperature dependence

    International Nuclear Information System (INIS)

    Palmero, E. M.; Bran, C.; Real, R. P. del; Vázquez, M.; Magén, C.

    2014-01-01

    Arrays of Ni 100−x Cu x nanowires ranging in composition 0 ≤ x ≤ 75, diameter from 35 to 80 nm, and length from 150 nm to 28 μm have been fabricated by electrochemical co-deposition of Ni and Cu into self-ordered anodic aluminum oxide membranes. As determined by X-ray diffraction and Transmission Electron Microscopy, the crystalline structure shows fcc cubic symmetry with [111] preferred texture and preferential Ni or Cu lattice depending on the composition. Their magnetic properties such as coercivity and squareness have been determined as a function of composition and geometry in a Vibrating Sample Magnetometer in the temperature range from 10 to 290 K for applied magnetic fields parallel and perpendicular to the nanowires axis. Addition of Cu into the NiCu alloy up to 50% enhances both parallel coercivity and squareness. For the higher Cu content, these properties decrease and the magnetization easy axis becomes oriented perpendicular to the wires. In addition, coercivity and squareness increase by decreasing the diameter of nanowires which is ascribed to the increase of shape anisotropy. The temperature dependent measurements reflect a complex behavior of the magnetic anisotropy as a result of energy contributions with different evolution with temperature.

  7. Temperature-dependent stability of stacking faults in Al, Cu and Ni: first-principles analysis.

    Science.gov (United States)

    Bhogra, Meha; Ramamurty, U; Waghmare, Umesh V

    2014-09-24

    We present comparative analysis of microscopic mechanisms relevant to plastic deformation of the face-centered cubic (FCC) metals Al, Cu, and Ni, through determination of the temperature-dependent free energies of intrinsic and unstable stacking faults along [1 1̄ 0] and [1 2̄ 1] on the (1 1 1) plane using first-principles density-functional-theory-based calculations. We show that vibrational contribution results in significant decrease in the free energy of barriers and intrinsic stacking faults (ISFs) of Al, Cu, and Ni with temperature, confirming an important role of thermal fluctuations in the stability of stacking faults (SFs) and deformation at elevated temperatures. In contrast to Al and Ni, the vibrational spectrum of the unstable stacking fault (USF[1 2̄ 1]) in Cu reveals structural instabilities, indicating that the energy barrier (γusf) along the (1 1 1)[1 2̄ 1] slip system in Cu, determined by typical first-principles calculations, is an overestimate, and its commonly used interpretation as the energy release rate needed for dislocation nucleation, as proposed by Rice (1992 J. Mech. Phys. Solids 40 239), should be taken with caution.

  8. Analysis of microwave heating of materials with temperature-dependent properties

    International Nuclear Information System (INIS)

    Ayappa, K.G.; Davis, H.T.; Davis, E.A.; Gordon, J.

    1991-01-01

    In this paper transient temperature profiles in multilayer slabs are predicted, by simultaneously solving Maxwell's equations with the heat conduction equation, using Galerkin-finite elements. It is assumed that the medium is homogeneous and has temperature-dependent dielectric and thermal properties. The method is illustrated with applications involving the heating of food and polymers with microwaves. The temperature dependence of dielectric properties affects the heating appreciably, as is shown by comparison with a constant property model

  9. A Temperature-Dependent Thermal Model of IGBT Modules Suitable for Circuit-Level Simulations

    DEFF Research Database (Denmark)

    Wu, Rui; Wang, Huai; Ma, Ke

    2014-01-01

    Thermal impedance of IGBT modules may vary with operating conditions due to that the thermal conductivity and heat capacity of materials are temperature dependent. This paper proposes a Cauer thermal model for a 1700 V/1000 A IGBT module with temperature-dependent thermal resistances and thermal ...... relevant reliability aspect performance. A test bench is built up with an ultra-fast infrared (IR) camera to validate the proposed thermal impedance model....

  10. Temperature dependence of 1H NMR relaxation time, T2, for intact and neoplastic plant tissues

    Science.gov (United States)

    Lewa, Czesław J.; Lewa, Maria

    Temperature dependences of the spin-spin proton relaxation time, T2, have been shown for normal and tumorous tissues collected from kalus culture Nicotiana tabacum and from the plant Kalanchoe daigremontiana. For neoplastic plant tissues, time T2 was increased compared to that for intact plants, a finding similar to that for animal and human tissues. The temperature dependences obtained were compared to analogous relations observed with animal tissues.

  11. Plasticity of gene-regulatory networks controlling sex determination: of masters, slaves, usual suspects, newcomers, and usurpators.

    Science.gov (United States)

    Herpin, Amaury; Schartl, Manfred

    2015-10-01

    Sexual dimorphism is one of the most pervasive and diverse features of animal morphology, physiology, and behavior. Despite the generality of the phenomenon itself, the mechanisms controlling how sex is determined differ considerably among various organismic groups, have evolved repeatedly and independently, and the underlying molecular pathways can change quickly during evolution. Even within closely related groups of organisms for which the development of gonads on the morphological, histological, and cell biological level is undistinguishable, the molecular control and the regulation of the factors involved in sex determination and gonad differentiation can be substantially different. The biological meaning of the high molecular plasticity of an otherwise common developmental program is unknown. While comparative studies suggest that the downstream effectors of sex-determining pathways tend to be more stable than the triggering mechanisms at the top, it is still unclear how conserved the downstream networks are and how all components work together. After many years of stasis, when the molecular basis of sex determination was amenable only in the few classical model organisms (fly, worm, mouse), recently, sex-determining genes from several animal species have been identified and new studies have elucidated some novel regulatory interactions and biological functions of the downstream network, particularly in vertebrates. These data have considerably changed our classical perception of a simple linear developmental cascade that makes the decision for the embryo to develop as male or female, and how it evolves. © 2015 The Authors.

  12. Effect of temperature-dependent energy-level shifts on a semiconductor's Peltier heat

    International Nuclear Information System (INIS)

    Emin, D.

    1984-01-01

    The Peltier heat of a charge carrier in a semiconductor is calculated for the situation in which the electronic energy levels are temperature dependent. The temperature dependences of the electronic energy levels, generally observed optically, arise from their dependences on the vibrational energy of the lattice (e.g., as caused by thermal expansion). It has been suggested that these temperature dependences will typically have a major effect on the Peltier heat. The Peltier heat associated with a given energy level is a thermodynamic quantity; it is the product of the temperature and the change of the entropy of the system when a carrier is added in that level. As such, the energy levels cannot be treated as explicitly temperature dependent. The electron-lattice interaction causing the temperature dependence must be expressly considered. It is found that the carrier's interaction with the atomic vibrations lowers its electronic energy. However, the interaction of the carrier with the atomic vibrations also causes an infinitesimal lowering (approx.1/N) of each of the N vibrational frequencies. As a result, there is a finite carrier-induced increase in the average vibrational energy. Above the Debye temperature, this cancels the lowering of the carrier's electronic energy. Thus, the standard Peltier-heat formula, whose derivation generally ignores the temperature dependence of the electronic energy levels, is regained. This explains the apparent success of the standard formula in numerous analyses of electronic transport experiments

  13. A single sex pheromone receptor determines chemical response specificity of sexual behavior in the silkmoth Bombyx mori.

    Science.gov (United States)

    Sakurai, Takeshi; Mitsuno, Hidefumi; Haupt, Stephan Shuichi; Uchino, Keiro; Yokohari, Fumio; Nishioka, Takaaki; Kobayashi, Isao; Sezutsu, Hideki; Tamura, Toshiki; Kanzaki, Ryohei

    2011-06-01

    In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z)-10,12-hexadecadienol (bombykol), is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z)-11-hexadecenal (Z11-16:Ald), in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of bombykol receptor neurons alone is sufficient to trigger full sexual behavior. Thus, a single gene defines behavioral selectivity in sex pheromone communication in the silkmoth. Our findings show that a single molecular determinant can not only function as a modulator of behavior but also as an all-or-nothing initiator of a complex species-specific behavioral sequence.

  14. A single sex pheromone receptor determines chemical response specificity of sexual behavior in the silkmoth Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Takeshi Sakurai

    2011-06-01

    Full Text Available In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z-10,12-hexadecadienol (bombykol, is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z-11-hexadecenal (Z11-16:Ald, in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of bombykol receptor neurons alone is sufficient to trigger full sexual behavior. Thus, a single gene defines behavioral selectivity in sex pheromone communication in the silkmoth. Our findings show that a single molecular determinant can not only function as a modulator of behavior but also as an all-or-nothing initiator of a complex species

  15. Population and colony-level determinants of tertiary sex ratio in the declining barn swallow.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Sex ratio of adults (tertiary sex ratio, TSR is a major feature of animal populations with consequences for their behaviour, genetic structure and viability. Spatial and temporal variation in TSR occurs within species but the mechanisms behind it are poorly understood. In this long-term study of a declining population of a socially monogamous, colonial, migratory bird, the barn swallow (Hirundo rustica, we first analyzed population-level variation in TSR ( =  proportion of males of yearlings at sexual maturation in relation to ecological conditions as gauged by annual survival rate of adults. TSR was male-biased both among yearlings and older individuals, but male bias of yearlings was more pronounced after years with larger decline in adult survival. Thus, male offspring were less susceptible to the adverse ecological conditions that cause increased mortality. Dispersal and settling site decisions can have major consequences on fitness via the effects of local TSR on mating and sperm competition. Breeding barn swallows are highly philopatric while natal dispersal is high and, together with mortality, is the main determinant of colony TSR. We thus also investigated the mechanisms of breeding colony choice by yearlings and found that TSR of new-settlers in a given colony and year was negatively predicted by TSR of returning, early arriving older individuals in that year, but not by overall TSR at the colony in the previous year. This suggests that in our male-biased population new-settler males respond to local TSR upon arrival to choose the sites with larger breeding opportunities. Hence, variation in ecological conditions as reflected by adult survival can shift the TSR of individuals recruiting into a local population, with potentially various demographic consequences. However, breeding site choice based on TSR tends to homogenize TSR at a population level likely by facilitating settling of dispersing males in colonies with less male

  16. Dynamic karyotype evolution and unique sex determination systems in Leptidea wood white butterflies.

    Science.gov (United States)

    Šíchová, Jindra; Voleníková, Anna; Dincă, Vlad; Nguyen, Petr; Vila, Roger; Sahara, Ken; Marec, František

    2015-05-19

    Chromosomal rearrangements have the potential to limit the rate and pattern of gene flow within and between species and thus play a direct role in promoting and maintaining speciation. Wood white butterflies of the genus Leptidea are excellent models to study the role of chromosome rearrangements in speciation because they show karyotype variability not only among but also within species. In this work, we investigated genome architecture of three cryptic Leptidea species (L. juvernica, L. sinapis and L. reali) by standard and molecular cytogenetic techniques in order to reveal causes of the karyotype variability. Chromosome numbers ranged from 2n = 85 to 91 in L. juvernica and 2n = 69 to 73 in L. sinapis (both from Czech populations) to 2n = 51 to 55 in L. reali (Spanish population). We observed significant differences in chromosome numbers and localization of cytogenetic markers (rDNA and H3 histone genes) within the offspring of individual females. Using FISH with the (TTAGG) n telomeric probe we also documented the presence of multiple chromosome fusions and/or fissions and other complex rearrangements. Thus, the intraspecific karyotype variability is likely due to irregular chromosome segregation of multivalent meiotic configurations. The analysis of female meiotic chromosomes by GISH and CGH revealed multiple sex chromosomes: W1W2W3Z1Z2Z3Z4 in L. juvernica, W1W2W3Z1Z2Z3 in L. sinapis and W1W2W3W4Z1Z2Z3Z4 in L. reali. Our results suggest a dynamic karyotype evolution and point to the role of chromosomal rearrangements in the speciation of Leptidea butterflies. Moreover, our study revealed a curious sex determination system with 3-4 W and 3-4 Z chromosomes, which is unique in the Lepidoptera and which could also have played a role in the speciation process of the three Leptidea species.

  17. Developmental expression of "germline"- and "sex determination"-related genes in the ctenophore Mnemiopsis leidyi.

    Science.gov (United States)

    Reitzel, Adam M; Pang, Kevin; Martindale, Mark Q

    2016-01-01

    An essential developmental pathway in sexually reproducing animals is the specification of germ cells and the differentiation of mature gametes, sperm and oocytes. The "germline" genes vasa, nanos and piwi are commonly identified in primordial germ cells, suggesting a molecular signature for the germline throughout animals. However, these genes are also expressed in a diverse set of somatic stem cells throughout the animal kingdom leaving open significant questions for whether they are required for germline specification. Similarly, members of the Dmrt gene family are essential components regulating sex determination and differentiation in bilaterian animals, but the functions of these transcription factors, including potential roles in sex determination, in early diverging animals remain unknown. The phylogenetic position of ctenophores and the genome sequence of the lobate Mnemiopsis leidyi motivated us to determine the compliment of these gene families in this species and determine expression patterns during development. Our phylogenetic analyses of the vasa, piwi and nanos gene families show that Mnemiopsis has multiple genes in each family with multiple lineage-specific paralogs. Expression domains of Mnemiopsis nanos, vasa and piwi, during embryogenesis from fertilization to the cydippid stage, were diverse, with little overlapping expression and no or little expression in what we think are the germ cells or gametogenic regions. piwi paralogs in Mnemiopsis had distinct expression domains in the ectoderm during development. We observed overlapping expression domains in the apical organ and tentacle apparatus of the cydippid for a subset of "germline genes," which are areas of high cell proliferation, suggesting that these genes are involved with "stem cell" specification and maintenance. Similarly, the five Dmrt genes show diverse non-overlapping expression domains, with no clear evidence for expression in future gametogenic regions of the adult. We also

  18. Effects of aromaticity in cations and their functional groups on the temperature dependence of low-frequency spectrum

    Science.gov (United States)

    Kakinuma, Shohei; Ramati, Sharon; Wishart, James F.; Shirota, Hideaki

    2018-05-01

    In this study, we investigate the temperature dependence of low-frequency spectra in the frequency range of 0.3-200 cm-1 for ionic liquids (ILs) whose cations possess two systematically different cyclic groups, using femtosecond Raman-induced Kerr effect spectroscopy. The target ILs are bis(trifluoromethylsulfonyl)amide [NTf2]- salts of 1-cyclohexylmethyl-1-methylpyrrolidinium [CHxmMPyrr]+, 1-cyclohexylmethyl-3-methylimidazolium [CHxmMIm]+, N-cyclohexylmethylpyridinium [CHxmPy]+, 1-benzyl-1-methylpyrrolidinium [BzMPyrr]+, 1-benzyl-3-methylimidazolium [BzMIm]+, and N-benzylpyridinium [BzPy]+ cations. The aim of this study is to better understand the effects of aromaticity in the cations' constituent groups on the temperature-dependent low-frequency spectral features of the ILs. The low-frequency spectra of these ILs are temperature dependent, but the temperature-dependent spectrum of [CHxmMPyrr][NTf2] is different from that of other ILs. While [CHxmMPyrr][NTf2] shows spectral changes with temperature in the low-frequency region below 50 cm-1, the other ILs also show spectral changes in the high-frequency region above 80 cm-1 (above 50 cm-1 in the case of [BzMPyrr][NTf2]). We conclude that the spectral change in the low-frequency region is due to both the cation and anion, while the change in the high-frequency region is attributed to the red shift of the aromatic ring librations. On the basis of the plots of the first moment of the spectra vs. temperature, we found that the first moment of the low-frequency spectrum of the IL whose cation does not have an aromatic ring is less temperature dependent than that of the other ILs. However, the intrinsic first moment, the first moment at 0 K, of the low-frequency spectrum is governed by the absence or presence of a charged aromatic group, while a neutral aromatic group does not have much influence on determining the intrinsic first moment.

  19. A temperature dependent cyclic plasticity model for hot work tool steel including particle coarsening

    Science.gov (United States)

    Jilg, Andreas; Seifert, Thomas

    2018-05-01

    Hot work tools are subjected to complex thermal and mechanical loads during hot forming processes. Locally, the stresses can exceed the material's yield strength in highly loaded areas as e.g. in small radii in die cavities. To sustain the high loads, the hot forming tools are typically made of martensitic hot work steels. While temperatures for annealing of the tool steels usually lie in the range between 400 and 600 °C, the steels may experience even higher temperatures during hot forming, resulting in softening of the material due to coarsening of strengthening particles. In this paper, a temperature dependent cyclic plasticity model for the martensitic hot work tool steel 1.2367 (X38CrMoV5-3) is presented that includes softening due to particle coarsening and that can be applied in finite-element calculations to assess the effect of softening on the thermomechanical fatigue life of hot work tools. To this end, a kinetic model for the evolution of the mean size of secondary carbides based on Ostwald ripening is coupled with a cyclic plasticity model with kinematic hardening. Mechanism-based relations are developed to describe the dependency of the mechanical properties on carbide size and temperature. The material properties of the mechanical and kinetic model are determined on the basis of tempering hardness curves as well as monotonic and cyclic tests.

  20. Temperature dependence of the evaporation lengthscale for water confined between two hydrophobic plates.

    Science.gov (United States)

    Djikaev, Yuri S; Ruckenstein, Eli

    2015-07-01

    Liquid water in a hydrophobic confinement is the object of high interest in physicochemical sciences. Confined between two macroscopic hydrophobic surfaces, liquid water transforms into vapor if the distance between surfaces is smaller than a critical separation, referred to as the evaporation lengthscale. To investigate the temperature dependence of the evaporation lengthscale of water confined between two hydrophobic parallel plates, we use the combination of the density functional theory (DFT) with the probabilistic hydrogen bond (PHB) model for water-water hydrogen bonding. The PHB model provides an analytic expression for the average number of hydrogen bonds per water molecule as a function of its distance to a hydrophobic surface and its curvature. Knowing this expression, one can implement the effect of hydrogen bonding between water molecules on their interaction with the hydrophobe into DFT, which is then employed to determine the distribution of water molecules between two macroscopic hydrophobic plates at various interplate distances and various temperatures. For water confined between hydrophobic plates, our results suggest the evaporation lengthscale to be of the order of several nanometers and a linearly increasing function of temperature from T=293 K to T=333 K, qualitatively consistent with previous results. Copyright © 2015 Elsevier Inc. All rights reserved.