Hard life for sons in the nest?Sex-dependent offspring mortality in Great Tits in urban and forest areas

Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expression of mutations linked to sex chromosomes.The extent of sex-bias in mortality may also be related to environmental conditions that influence offspring development and survival.Urban areas often provide poorer conditions for nestling development resulting in higher offspring mortality compared to natural areas,which may accelerate sex differences in offspring mortality in cities.To test this hypothesis,we examined the sex ratio of dead offspring in Great Tits(Parus major),using 427 samples of unhatched eggs and dead nestlings collected in two urban and two forest sites between 2013 and 2019.The ratio of males in the whole sample of dead offspring(56.9%)was significantly higher than expected by an 1:1 ratio,and the strongest sex biases were detected in urban areas(57.6%males)and in young nestlings(<14 days old,59.0%males).However,the sex ratios of dead offspring did not differ significantly among study sites and between offspring developmental stages.29.3%of unhatched eggs contained a visible embryo,and the proportion of embryo-containing unhatched eggs did not differ significantly between urban and forest study sites.These results suggest male-biased offspring mortality in Great Tits,and highlight the need of large datasets to detect subtle differences between habitats and developmental stages.

Age-specific mortality and fecundity of a spider mite under diet restriction and delayed mating

Numerous experimental life-history studies on aging are mainly baised on two classical models—fruit fly Drosophila melanogaster(Meigen)and nematode Caenorhab-ditis elegans(Maupas)—with relatively little attention given to other organisms with different life-history characters.Two-spotted spider mite Tetranychus urticae Koch(Acari:Tetranychidae)differs from many other arthropods in that the females continue their growth in the early adult stage and can reproduce sexually and asexually.In this study,the influences of dietary restriction and delayed mating on the aging patterns of the spider mite were examined with the prevailing survival and reproduction trade-off hypothesis of aging being tested.Significant sex-specific responses of the spider mites were found.The females showed longevity extension on diet restriction(fasting for 2 days in every 4 days)compared with their counterparts being fed ad libitum,and after delayed mating for 9 days,while the males displayed a decrease in lifespan when experiencing diet restriction but were not significantly influenced by delayed mating.Path analysis was used to investigate the relationship between mite survival and reproduction traits,including longevity,female lifetime reproduction,age at first reproduction,early reproductive efforts and late reproductive efforts,yielding no evidence for trade-offs between these life-history traits.The additive effects of dietary restriction and delayed mating in lifespan extension of female spider mites were confirmed,proving that diet restriction is a robust anti-aging intervention,and that later onset of reproduction can prolong adult lifespan in females.

中国婴儿死亡率性别比的地域差异

目的文章利用全国第3～5次人口普查资料,描述了1981～2000年中国婴儿死亡率性别比的变化趋势和地域差异。方法利用并结合全国社会、经济和文化等资料对影响婴儿死亡率性别比地域差异的原因进行多因素分析。结果研究结果显示,我国的婴儿死亡率性别比自80年代初开始出现异常(女婴死亡率高于男婴),其严重程度随时间推移不断加剧。全国婴儿死亡率性别比从1981年的1.05,下降到1989年的0.87和2000年的0.72。死亡率性别比异常的省份从1981年的4个增加到1989年的19个和2000年的26个。1981年各省份婴儿死亡率性别比最低为0.87,1989年最低为0.77,2000年最低至0.40。异常程度严重的地区包括安徽、江西、广西、广东、海南等省份。结论在现行的计划生育政策背景下,造成婴儿死亡率性别比地区差异的主要原因是偏好男婴的传统观念在不同地区的差别,其次与不同地区计划生育政策执行力度不同有关,而与不同地区经济水平的关联度较小。

死亡率性别差异对终身寿险纯保费的影响分析

利用《中国人寿保险业经验生命表(2000-2003)》的数据,定义一个纯保费性别比率(PR)函数,分析死亡率性别差异对终身寿险纯保费性别差异的影响。对于同一年龄不同性别的投保人,预定利率越高,PR值越大;在不同的预定利率下,PR值差异随着投保人年龄的增加而先增加后不断缩小,PR值随着投保人投保年龄的上升而下降。

Sex-Dependent Glial Signaling in Pathological Pain:Distinct Roles of Spinal Microglia and Astrocytes

Increasing evidence suggests that spinal micro- glia regulate pathological pain in males. In this study, we investigated the effects of several microglial and astroglial modulators on inflammatory and neuropathic pain follow- ing intrathecal injection in male and female mice. These modulators were the microglial inhibitors minocycline and ZVEID （a caspase-6 inhibitor） and the astroglial inhibitors L-α-aminoadipate （L-AA, an astroglial toxin） and car- benoxolone （a connexin 43 inhibitor）, as well as U0126 （an ERK kinase inhibitor） and D-JNKI-1 （a c-Jun N-terminal kinase inhibitor）. We found that spinal administration of minocycline or ZVEID, or Caspase6 deletion, reduced formalin-induced inflammatory and nerve injury-induced neuropathic pain primarily in male mice. In contrast, intrathecal L-AA reduced neuropathic pain but not inflam- matory pain in both sexes. Intrathecal U0126 and D-JNKI- 1 reduced neuropathic pain in both sexes. Nerve injury caused spinal upregulation of the astroglial markers GFAP and Connexin 43 in both sexes. Collectively, our data confirmed male-dominant microglial signaling but also revealed sex-independent astroglial signaling in the spinal cord in inflammatory and neuropathic pain.

Heart Failure with Preserved Ejection Fraction:Time to Revisit the Stiff Heart

In the current era of cardiovascular disease,the diagnosis of heart failure with preserved ejection fraction(HFpEF)is a well-recognized clinical entity that is equally prevalent but distinctly different from heart failure with reduced ejection fraction(HFrEF).Despite normal EF patients with this disease have similar morbidity and mortality rates compared with HFrEF,as well as a rising rate of hospitalizations.The pathophysiology of HFpEF is incompletely understood.The number of therapies with proven effi cacy at improving longterm cardiovascular outcomes is limited.Women with heart failure syndromes,particularly the elderly,are much more likely to have a HFpEF phenotype at the time of their diagnosis.The purpose of this paper is to review the epidemiology,pathophysiology,clinical features,and current management strategies in HFpEF,especially as it pertains to women.

Reproductive biology of Gazella arabica: Predictors of offspring weight and short- and long-term offspring survival

Reproductive traits are central to organismal fitness,and so the factors influencing patterns of reproduction and offspring survival are at the heart of biology.Making use of breeding data collected over 16 years at the King Khalid Wildlife Research Centre in Saudi Arabia,we investigated the reproductive biology of Arabian gazelles Gazella arabica.Offspring survival was mainly a function of birth weight,with heavier offspring having higher survival rates than lighter offspring.However,while sons were heavier than daughters,daughters had higher survival rates.We could not find evidence that giving birth to sons negatively impacts offspring weight in the following year.We uncovered large narrow-sense heritability(h2)in offspring weight at birth,while maternal effects(m2)on birth weight were of lesser importance.However,maternal effects on offspring survival were strong until weaning age,while paternal effects dominated survival to sexual maturity and first reproduction.We propose that variation in maternal postnatal care might overshadow the effects of maternal inheritance of birth weights,while the overall strong heritability of weight at birth and the paternal effects on survival llustrates strong variance in sire fitness based on genetic quality,suggesting a role for sexual selectionbyfemalemate choiceinwildpopulations.

2004-2011年中国人群心血管病死亡的性别差异分析

目的分析我国主要心血管疾病死亡的性别差异及其变化情况，为提出有效的干预措施提供依据。方法利用全国疾病监测系统2004—2011年死因监测数据，分析不同年度、不同年龄组心血管病死亡性别比的差异和变化趋势，并对2010年不同地区间心血管疾病死亡性别比进行比较。结果2004—2011年，全国各主要心血管病死亡率除风湿性心脏病以外。均表现为男性高于女性，性别比（男性：女性）为1．37—1．59；各类心血管疾病死亡性别比呈逐年升高趋势，尤以其他心脏病的上升幅度最快；各年龄组心血管病死亡性别比均呈上升趋势，并表现为低年龄组上升速度较快的特点；心血管病死亡率性别比以30-45岁年龄组最高，75岁以上组最低。2010年，我国心血管病死亡率性别比表现为农村高于城市（其他心脏病除外）、东部地区高于中西部地区的特点。结论针对农村和东部地区，尤其是低年龄组男性人群开展心血管病的预防和干预，同时提示，女性人群风湿性心脏病的防治是今后心血管疾病的防治重点。