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981.
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On the basis of church register entries from the Krummhörn region (Ostfriesland, Germany, 1720-1874) we looked at whether the existence of grandmothers had an impact on the reproductive success of a family. We found that fertility measured by parity progression ratios was influenced by grandmothers, though only in exceptionally large families, while fertility measured by intervals between births was not influenced by grandmothers. However, maternal grandmothers reduced infant mortality when the children were between 6 and 12 months of age. During these 6 months, the relative risk of dying was approximately 1.8 times higher if the maternal grandmother was dead at the time of the child's birth compared to if she was alive. Interestingly, the existence of paternal grandmothers approximately doubled the relative risk of infant mortality during the 1st month of life. We interpret this as being the result of a tense relationship between mother- and daughter-in-laws. We found that Krummhörn grandmothers could be both helpful and a hindrance at the same time. Geographic proximity increased the effects found. If this ambivalent impact of grandmothers on familial reproduction could be generalized beyond the Krummhörn population, the hypothesis that the evolution of the postgenerative life span could be explained by grandmotherly kin-effects would have to be stated more precisely: the costs of social stress in the male descendency would have to be subtracted from the benefits of aid and assistance in the female descendency. 相似文献
984.
Female pied flycatchers Ficedula hypoleuca choose male characteristics in homogeneous habitats 总被引:2,自引:0,他引:2
Summary The paper reports the results of a 2-year study of pairing success of male pied flycatchers in a homogeneous habitat. A handicapping experiment was carried out in which certain wing and tail feathers were removed from randomly selected males. Handicapped males had reduced pairing success, they lost weight, and they sang less frequently than control males. Male pairing success was positively correlated with the darkness of the plumage, body-size, and previous breeding experience. Earlier studies on the same species have failed to detect any relationships between pairing success and male characteristics, possibly because of habitat heterogeneity and variation in nest site quality. The evolutionary basis for female choice of male characteristics is discussed. There are reports that males with attractive traits (e.g. black plumage) provide a high quality of parental care. However, the fact that male pairing success was related to male conspicuousness makes it difficult to discriminate between active and passive female choice. 相似文献
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987.
Heikens A Widianarko B Dewi IC de Boer JL Seinen W van Leeuwen K 《Environmental geochemistry and health》2005,27(5-6):475-483
In Asembagus (East Java, Indonesia), surface water is contaminated with effluent from the hyperacid Ijen Crater Lake. In a
previous study, we reported that food crops irrigated with this water had increased concentrations of various elements. Here,
we present a total diet study for adults and 6-year-old children to determine if the mean daily intake of a broad range of
elements is safe and adequate. For children, the intake of B, Mg, Mn and V is high with Hazard Quotients (HQ) of 1.1 (B),
1.4 (Mn) and 1.4 (V), respectively (no TDI is available for Mg). For Mn, the daily intake is high due to the consumption of
locally produced rice. Drinking water is the main source of B, Mg and V. For adults, the intake of Mg, Mn and V is also high
but HQ values are ≤0.7. For both children and adults, the intake of Ca, Zn and particularly Fe is below the RNI (Fe intake
is 90% below the RNI for women). It is concluded the mean intake of elements is unbalanced and Fe deficiency is probably the
most serious health problem. Toxic effects cannot be fully excluded since deficiency of essential elements such as Ca, Fe
and Zn can increase the absorption and retention of various elements. 相似文献
988.
Summary Columbian ground squirrels (Spermophilus columbianus) were live-trapped from 5 to 7 years at three sites in southwestern Alberta, Canada. The two most common adult matrilineal relatives for 2-year-old females were the mother and a 1 year older non-littermate sister. Co-occurrence of female kin depended firstly on size and sexual composition of litters and secondly on age-specific survival and recruitment rates. Adult matrilineal kin frequently coexisted among breeding females of this species, leading us to predict a social system strorgly influenced by nepotism. However, the life history traits of S. columbianus suggest an adult female kin cluster unlike that found for other species of Spermophilus in which littermate sisters are common. If availability of adult female kin influences kin-differential behaviour, then female S. columbianus should favour mothers, daughters and non-ittermate sisters. 相似文献
989.
Gihad E. Chalouhi Anne-Maude Morency Roland De Vlieger José Maria Martinez Thomas Blanc Ryan Hodges Alexandra Gueneuc Greg Ryan Jan Deprest Eduard Gratacos Yves Ville 《黑龙江环境通报》2017,37(10):968-974
We reviewed data from a cohort of fetuses with ureterocele diagnosed and operated prenatally in four fetal therapy centers. Inclusion criteria were (1) ureterocele confirmed on detailed fetal ultrasound examination, (2) absence of additional fetal malformations, and (3) fetal intervention to decompress the ureterocele with local institutional review boards' approval. Data on sonographic follow-up, obstetrical, neonatal outcome, and postnatal evaluation were collected. Ten cases of prenatally treated ureterocele are described. Six cases benefited from a fetoscopy for laser incision and decompression, two cases had an ultrasound guided puncture before resorting to a fetoscopy with laser incision, one case had a balloon catheterization under ultrasound guidance, and one case had an ultrasound-guided opening of the ureterocele with a laser fiber passed through a 20-gauge needle. Mean gestational age at diagnosis was 21.6 GW. Two cases underwent termination of pregnancy. The remaining eight cases recovered normal amniotic fluid volume and delivered a liveborn child at a mean gestational age of 38.6 GW with normal creatinine levels during the first week of life. Prenatal incision provided complete treatment of severely obstructive ureteroceles in 80% of the cases and allowed improvement of urinary electrolytes, renal size and echogenicity, bladder filling in all survivors, and recollection of normal amniotic fluid volume, in case of oligoanhydramnios. © 2017 John Wiley & Sons, Ltd. 相似文献
990.