Asymmetric Hybridization and Introgression between Pink Salmon and Chinook Salmon in the Laurentian Great Lakes

Among Pacific salmon collected in the St. Marys River, five natural hybrids of pink salmon Oncorhynchus gorbuscha and chinook salmon O. tshawytscha and one suspected backcross have been detected using morphologic, meristic, and color evidence. One allozyme (LDH, l‐lactate dehydrogenase from muscle) and one nuclear DNA locus (growth hormone) for which species‐specific fixed differences exist were analyzed to detect additional hybrids and to determine if introgression had occurred. Restriction fragment length polymorphism of mitochondrial DNA (mtDNA) was used to identify the maternal parent of each hybrid. Evidence of introgression was found among the five previously identified hybrids. All hybrid specimens had chinook salmon mtDNA, indicating that hybridization between chinook salmon and pink salmon in the St. Marys River is asymmetric and perhaps unidirectional. Ecological, physiological, and sexual selection forces may contribute to this asymmetric hybridization. Introgression between these highly differentiated species has implications for management, systematics, and conservation of Pacific salmon.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142073/1/tafs0670.pd

Psychological distress by type of fertility barrier

BACKGROUND: We examined fertility-specific distress (FSD) and general distress by type of fertility barrier (FB). METHODS: In a random sample telephone survey, 580 US women reported their fertility intentions and histories. Six groups of women were identified: (i) no FBs, (ii) infertile with intent, (iii) infertile without intent, (iv) other fertility problems, (v) miscarriages and (vi) situational barriers. Multiple regression analyses were used to compare groups with FBs. RESULTS: Sixty-one percent reported FBs and 28% reported an inability to conceive for at least 12 months. The infertile with intent group had the highest FSD, which was largely explained by (a) self-identification as infertile and (b) seeking medical help for fertility. The no FB group had a mean Center for Epidemiological Studies Depression scale score above the commonly used cut-off of 16, although 23% of the women with FBs did score above 16. CONCLUSIONS: FBs are common. Self-identification as infertile is the largest source of FSD. More women with FBs had elevated general distress than women without FBs; mean general distress was below 16 for all FB groups. It may be that, for some women (even those with children), FBs can have lasting emotional consequences, but many women do heal from the emotional distress that may accompany fertility difficulties

Solid Freeform Fabrication of Ceramic Parts from Filler Loaded Preceramic Polymers

Manufacturing of ceramic parts was achieved by selective laser treatment of a preceramic polymer (polysiloxane) loaded with ceramic filler powder (alumina). Thin layers of polymer/filler powder mixture were sequentially cured with a CO2-laser (λ=10.6 µm) thereby generating the geometrical shape of the part. Subsequently, the cured thermoset part was annealed in nitrogen atmosphere at 600 to 1000 °C to convert the compact into a Si-OC/Al2O3 micro-composite material. Dimensional changes upon pyrolysis (∆l/l0 ≈ 3 %) can be controlled by adjusting the polymer-to-filler ratio and the heat treatment conditions. The new process is called Selective Laser Curing (SLC).Financial support of Fonds der Chemischen Industrie and Deutsche Forschungsgemeinschaft is gratefully acknowledged.Mechanical Engineerin

The Biological Standard of Living in the two Germanies.

Physical stature is used as a proxy for the biological standard of living in the two Germanies before and after unification in an analysis of a cross-sectional sample (1998) of adult heights, as well as among military recruits of the 1990s. West Germans tended to be taller than East Germans throughout the period under consideration. Contrary to official proclamations of a classless society, there were substantial social differences in physical stature in East-Germany. Social differences in height were greater in the East among females, and less among males than in the West. The difficulties experienced by the East-German population after 1961 is evident in the increase in social inequality of physical stature thereafter, as well as in the increasing gap relative to the height of the West-German population. After unification, however, there is a tendency for East-German males, but not of females, to catch up with their West-German counterparts

Experiencing male infertility: A review of the qualitative research literature

This article examines the qualitative research literature that exists in relation to men’s experiences of male infertility. Since men have often been marginalized in the realm of reproduction, including academic research on infertility, it is important to focus on any qualitative research that gives voices to male perspectives and concerns. Given the distress documented by studies of infertile women, we focus in particular on the emotive responses and lived experiences of men in relation to infertility. In this article then, we present an analysis of the core themes across 19 qualitative articles, which include “infertility as crisis”; “emoting infertility- men as “being strong”’ “infertility as a source of stigma”; and the “desire for fatherhood.” In light of these insights, we identify key areas for future research and development including men’s emotional responses to infertility, how men seek support for infertility, the intersection between masculinity and infertility, the relationship between the desire to father and infertility, and the outcomes of infertility for men in terms of other aspects of their lives. We suggest that such research would facilitate making the experiences of men more central within our understandings of infertility within a field that has primarily been female focused