首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
Buchbesprechung     
Abstract

Anthony A. Albanese: Newer Methods of Nutritional Biochemistry, Volume 1. — Erschienen bei Academic Press Inc., New York und London, 1963, 583 Seiten, Ganzleinen, Preis: $ 18,50. Reviewed by H. Bergner.  相似文献   

3.
Capsule Fæders (males that are female look-alikes) associate with males rather than females, at several different spatial scales.

Aims To test the prediction that the occurrence in space and time of fæders on ecological grounds should track that of females.

Methods The fraction of fæders was estimated in five morphometric data sets that were collected over four decades in four different countries in three different seasons (comprising 9133 Ruffs). The regression of fæder–female fractions was tested against the null model assuming that the number of fæders is 1.0% of females.

Results The fraction of fæders in catches averaged 1.03%, varying between 0.3% in autumn in the UK up to 0.85% in Sénégal in winter and 1.04% in The Netherlands in spring. On a stopover in The Netherlands the fraction decreased from 1.3% to 0.7% when the females started to arrive. At all four spatial and temporal scales the regression of fæder–female fractions deviated from the null model: we found high fractions of fæders in catches with low fractions of females, indicating that fæders rather associate with the larger-sized ‘normal’ males.

Conclusion We suggest that fæders spend the winter, and migrate with, the larger-sized lekking males, and we propose that any survival costs associated with the use of suboptimal habitats is compensated by higher reproductive success as sneakers on leks.  相似文献   

4.
GUNTHER TSCHUCH 《Bioacoustics.》2013,22(1-2):123-129
ABSTRACT

The stridulatory organs of male and female Mutillid wasps are similar and occur between their 3rd and 4th abdominal tergites. The three investigated species, Smicromyrme rufipes, Dasylabris kozlovi and Mutilla marginata, possess files with different ‘ripple’ distances that are species specific (2.5 to 5.4 micrometres). The sonagram of the distress calls from female M. marginata shows the ripple frequency with low amplitude rising in the first 20 milliseconds from 1.2 to 1.5 kHz and then falling back in the following 20 milliseconds. The main sound energy occurs in the 2nd and 3rd harmonics.  相似文献   

5.
ObjectiveIt was aimed to examine the changes in homocysteine, folic acid, and vitamin B12, which metabolize homocysteine from the body, and trace elements (zinc, copper, selenium, nickel) that affect the structure of tissues and epithelium in female patients with gallstone disease. Moreover, it was aimed to investigate the contribution of these selected parameters to the etiology of the disease and their usability in treatment according to the findings obtained.Materials and MethodsEighty patients, including 40 female patients (Group I) and 40 completely healthy female individuals (Group II) were included in this study. Serum homocysteine, vitamin B12, folate, zinc, copper, selenium, and nickel levels were evaluated. Electrochemiluminescence immunoassay was used in the analysis of vitamin B12, folic acid, and homocysteine levels, and the ICP-MS method was used in the analysis of trace element levels.ResultsHomocysteine levels in Group I were statistically significantly higher than in Group II. In terms of vitamin B12, zinc, and selenium, Group I levels were found to be statistically significantly lower than group II. There was no statistically significant difference between Group I levels and Group II in terms of copper, nickel, and folate.ConclusionIt was suggested that homocysteine, vitamin B12, zinc, and selenium levels should be determined in patients with gallstone disease and that vitamin B12, which is especially important in the excretion of homocysteine from the body, and zinc and selenium, which prevent the free radical formation and protect from its effects, should be added to the diets of these patients.  相似文献   

6.

CATHOLIC VIEWPOINT ON OVERPOPULATION: Anthony Zimmerman, S.V.D. Hanover House, New York, 1961, 214 pp., $3.50.

MANKIND EVOLVING: Theodosius Dobzhansky. Yale University Press, New Haven, 1962, xiii + 381 pp., $7.50.

THE SEARCH FOR A COMMON LEARNING: General Education, 1800–1960: Russell Thomas. McGraw‐Hill, New York, 1962, 324 pp., $6.95.

THE WORLD ROLE OF THE UNIVERSITIES: Edward W. Weidner. McGraw‐Hill, New York, 1962, 366 pp., $3.65.

RESEARCH IN FAMILY PLANNING: C. V. Kiser, ed. Princeton University Press, 1962, Princeton, pp. 662, $12.50.  相似文献   

7.
Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produced three pheromone components (IIII), which strongly stimulated male antennae. Using GC–MS analysis and chemical derivatizations, the following structures were estimated: 6-methyl-2-octadecanone (I), 14-methyl-2-octadecanone (II), and 6,14-dimethyl-2-octadecanone (III). While the stereochemistry of the chiral centers could not be determined because it was difficult to collect a sufficient amount of the natural pheromone, the plain structures of I and II were confirmed by synthesis of the racemic mixtures starting from diols. These methyl-branched ketones have not been identified as a natural product, indicating that they constitute a new chemical group of lepidopteran female sex pheromones.  相似文献   

8.
BackgroundCancer in children is increasingly recognized as a major and growing health problem in different developed and developing countries. In Yemen, it is still difficult to know the extent of cancer and its determinants among children. This study was conducted to determine the magnitude of childhood cancer in Aden and provide the preliminary baseline data by age and sex.MethodsBasic epidemiologic data was retrieved from all paediatric cancer <15 years age registered in Aden Caner Registry (ACR), Yemen, from 1997 to 2006.ResultsThe results showed a total of 483 childhood cancers <15 years age comprising12.7% of all registered malignancies with a male to female ratio of 1.5:1. The predominant age affected was 5–9 years in (38.3%) children. The most frequent cancer among Yemeni children was leukaemia 160 (33.1%) followed by lymphoma 152 (31.5%), CNS tumors 35 (7.2%) and bone tumours 25 (5.2%). An interesting and unusual finding was the frequency of acute myeloid leukaemia twice more common in female (66.7%) than male (33.3%). Lymphoma was the most common cancer in children >5 years. An interesting comparison was the preponderance of non-Hodgkins's lymphoma over Hodgkin's disease (1.6:1) stronger in female (3:1) than male (1.25:1). Medulloblastoma was the most common CNS tumour followed by astrocytoma, an infrequent finding in childhood cancer. Osteosarcoma was the most frequent bone tumour (male:female ratio of 1.8:1). A female preponderance was noticed in chondrosarcoma that was not yet documented. The blastoma group was common in younger age group. Retinoblastoma and nephroblastoma predominated in female while neuroblastoma, hepatoblastoma and soft tissue sarcomas in male.ConclusionIt is concluded that there is a lower frequency of childhood cancer in Aden when compared with developed countries. It may explained by the fact that a large number of childhood cancers remain undiagnosed due to limitations of diagnostic facilities or under registration. Central paediatric hospitals should be provided with essential diagnostic and therapeutic services that should be freely available to all children with cancer.  相似文献   

9.
《Gender Medicine》2012,9(5):295-308
BackgroundThe influence on, or interaction of, sex and dietary genistein on serum markers of cardiovascular health and cardiovascular function remain unclear.ObjectivesOur purpose was to examine the effects of a genistein-containing diet (600 mg/kg food) (600G) and a genistein-free diet (0G), on cardiovascular risk parameters of male and female mice.MethodsC57BL/6J mice were fed the diets for 1 month, after which time blood pressure, serum markers, and in vitro vascular reactivity was measured.ResultsMales fed the 600G diet gained significantly less weight than males fed the 0G diet (by 1.71 g); diet had no effect on female weight gain. Males fed the 600G diet also exhibited significantly elevated serum insulin (2.9 [0.5] vs 1.8 [0.4] ng/dL), and decreased serum glucose (0.15 [0.01] vs 0.24 [0.02] ng/dL) levels, resulting in a significant increase in the ratio of insulin to glucose; insulin and glucose levels were not changed by dietary genistein in females. Arterial pressure measurements from 0G-fed males were lower than other groups. However, basal vascular reactivity of isolated aortic rings was significantly increased by the 600G diet in both males (from 0.55 [0.03] to 0.94 [0.18] g) and females (from 0.45 [0.04] to 0.78 [0.09] g). Aortic wall thickness was not affected by diet. Norepinephrine-mediated contractility was also greater in aortic rings of male and female mice fed the 600G diet, and differences from the 0G diet persisted in the presence of L-NG-nitroarginine methyl ester but were completely accounted for by increased basal reactivity.ConclusionOur data indicate that 1 month of a 600G or 0G diet significantly alters vascular function independent of sex. In contrast, sex-dependent differences exist in well-established serum markers of cardiovascular health and disease.  相似文献   

10.
Abstract

Do common ethnicity and ethnic solidarity constitute preconditions for the successful formation of modern nations? In response to Anthony Smith's contention to this effect, it is here argued that ethnic solidarity at a large‐enough scale to constitute a nation is a problematic notion. Solidarities beyond small local communities require ideological and political underpinning. Rather than being preconditions of nation‐formation, ethnic homogeneity and solidarity are often products of a stable history of state and nation formation. The failures of some modern nation‐states with diverse ethnic compositions are an indication of inadequacy of resources for achieving stable ‘governability’.  相似文献   

11.
Abstract

Results from a survey of the tuatara populations on Hongiora and Ruamahua-iti Islands, conducted in March 1986, do not support an earlier report that the Hongiora population is declining (Crook 1973). On Hongiora, 49 captures were made of 43 tuatara over 12 man-hours, and on Ruamahua-iti, 67 captures of 60 tuatara were made over 12.5 man-hours. The mean body lengths of Hongiora tuatara (male=250.4 mm, female=220.8 mm) were significantly larger than those of Ruamahua-iti animals (male= 187.6mm, female= 179.3 mm). We question the interpretation that the smaller average size of tuatara on Ruamahua-iti Island indicates that they are younger than those on Hongiora Island.  相似文献   

12.
《Gender Medicine》2012,9(6):524-535
ObjectiveTo investigate the role of sex and the role of ammonia and amino acid metabolism, specifically the activity of glutamine synthetase, in survival and disease progression in amyotrophic lateral sclerosis.MethodsWe tested treatment with methionine sulfoximine (MSO) on the lifespan and neuromuscular ability of male and female SOD1 mice as measured by their ability to maintain their grip on an inverted wire grid. We also tested the effects of castration and ovariectomization on those measurements.ResultsMSO treatment improves the survival of both male and female mice, but the effects are significantly greater on female mice. Saline-treated (control) female mice have delayed neuromuscular degeneration compared with saline-treated male mice, and MSO further delays disease progression in females, to a greater extent than in males. Ovariectomization or castration completely eliminates the effect of the drug on either survival or neuromuscular deterioration.ConclusionsSex is an important factor in disease progression and the response of SOD1 mice to a drug targeting a central enzyme in nitrogen metabolism, with female sex hormones playing a greater role than male sex hormones. Glutamine synthetase, or its reactants and products, therefore plays a role in this disease, and the sex specificity of treatments aimed at this or other metabolic targets may therefore be an important factor in the development of therapies to treat amyotrophic lateral sclerosis.  相似文献   

13.
ABSTRACT

Introduction. Pallavicinia lyellii is recognised as being of principal importance for conservation in England and is threatened with extinction in Europe. The aims of this study were to investigate the current status, conservation and ecology of the species in S Hampshire, a key region for the plant.

Methods. All recent and historic locations for Pallavicinia lyellii in S Hampshire were searched and information collected on distribution, abundance and ecology.

Results. Pallavicinia lyellii was re-found at three sites. It is almost certainly extinct at two sites and may have been lost from a third. Whilst few colonies were sterile, most comprised a single sex. Colonies with both male and female plants were confined to Cadnam Bog, which supported 49 (91%) of the colonies found. Overall, female shoots occurred at 41 (76%) colonies and males at 26 (48%), producing a female sex bias (1.6:1). All colonies occur in boggy woodland, mostly on the sides of low mounds of damp, acidic, peaty soil developed, due to poaching by ponies and cattle, at the base of trees, usually I. aquifolium. The community mainly comprises a species-poor mix of acidophilous mosses and liverworts, most frequently Mnium hornum, Pseudotaxiphyllum elegans and Leucobryum juniperoideum.

Conclusions. Cadnam Bog appears to support the largest sexually reproducing population of Pallavicinia lyellii in England. The site is specially protected, actively managed with consideration to P. lyellii and seemingly in favourable condition for the plant. Research is needed to quantify canopy shade favoured by the plant and assess implications for woodland management. Future monitoring should include re-survey of populations every 3?yr.  相似文献   

14.
Summary

Surface architecture and selected ultrastructural features of normal embryos of the marine gastropod Ilyanassa obsoleta have been investigated using scanning and transmission electron microscopy. A re-examination of the classic account of Anthony Clement on temporal and division patterns in normal and lobeless embryos confirms most of his observations; a few differences, involving the size and positioning of micromere 4d and its derivatives, are noted. Several hypotheses are presented to account for zonular distribution of longer microvilli on some blastomere surfaces and progressive diminution of microvilli on micromere surfaces, especially the leading edge micromeres (LEMs), during postulated epibolic spreading movements. Microfilaments, discovered in the cortical regions of the LEMs, are described, and a role for these structures in gastrulation is proposed.  相似文献   

15.
Summary

Twenty-three immature female crayfish (Procambarus clarki (Girard); carapace length = 8.2–17.9 mm), implanted with androgenic gland implants obtained from P. clarki males, were observed for 326 days for evidence of masculinization. Number of molts completed ranged from three to eight. Of eleven surviving females, three were masculinized as evidenced by the partial transformation of their first pair of pleopods into male-type gonopods. No other evidence of masculinization, either internal or external was seen. Masculinization of the first pair of pleopods was unequal and first noted 290 days post-implantation. We conclude that androgenic gland implantation can induce masculinization of P. clarki females, albeit only with great difficulty. This is the first report of masculinization of female macruran decapods by androgenic gland implantation.  相似文献   

16.
BackgroundElite female athletes have shown vulnerability to various degrees of iron deficiency. Less is known about recreational fitness exercisers. A study was done to examine plasma ferritin, an assessor of iron status, in young adult, university student fitness runners.MethodsThe present study examined serum ferritin concentrations, an indicator of iron status, in 39 female university students (age 18–25) who ran for fitness, but ran less than competition runners. Selected subjects all reported themselves as not anemic.ResultsMean + SD for 3 mile run time was 26.25 + 3.0 min. The mean ferritin reading was low: 12.4 + 12.3 ng/mL (+ SD). Out of the 39 women, 29 had readings that fell below 15 ng/mL, which some consider the cutoff for iron deficiency. In addition, all but 2 subjects had values below 35, which has been proposed as Stage 1 iron deficiency for athletes. Ferritin levels did not correlate with 3 mile run times (Pearson correlation coefficient, P > 0.05). A 1 mo intervention with 3 minerals that included iron (36 mg/day) significantly raised ferritin values when the iron was bisglycinate (p < 0.05), but not when it was ferrous sulfate (p > 0.05).ConclusionIn this study, a degree of iron deficiency was seen in most of a group of female fitness runners (each of whom had self reported as not being anemic).  相似文献   

17.
Abstract

Intraspecific interactions (male‐male, female‐female, male‐female) of Argyrodes antipodiana (O.P.‐Cambridge), a New Zealand kleptoparasitic spider, were studied in the laboratory. Interactions, especially male‐female interactions, tended to be complex and of long duration, and included 32 different displays being used in sequences that could last for over 5 h. In male‐female interactions, there were numerous alternations between displaying and copulating, but most courtship followed the initial copulation. The possible adaptive significance of A. antipodiana's complex courtship is discussed. The role of pheromones in the intraspecific interactions of this species is also investigated.  相似文献   

18.
Background and aimsThis paper is about pollen ecophysiology, anther opening, pollen dispersal and the timing of the male and female phases in Parietaria judaica (Urticaceae).MethodsEcophysiological (effects of different relative humidities (RHs) and osmotic relationships) and cytological methods (stigmatic receptivity, pollen viability, histology and histochemistry) were used to determine pollen and pollination features during the long blooming period of this species.Key resultsPollen is dispersed by rapid uncurling of the filament and anther opening. The filament and anther lack cells with lignified wall thickenings, which are usually responsible for anther opening and ballistic pollen dispersal. Instead, dispersal is the result of the sudden movement of the filament. Pollen is of the partially hydrated type, i.e. with a water content greater than 30% at shedding, and readily loses water, and hence viability, at low RH. Pollen carbohydrate reserves differ with season. Starchless grains germinate quickly and are less subject to water loss. Flowers are protogynous, pollen release occurring only after complete cessation of the female phase within an inflorescence.ConclusionParietaria has partially hydrated pollen which differs from typical pollen of this type because of its reduced size and the absence of callose. Because of its low water content at the time of shedding it survives better at higher RH. Dispersal and pollination are adapted to pollen features.  相似文献   

19.
Four new species of Alaus Eschscholtz, 1829 are described: A. cinnamomeus n. sp., A. latlpennls n. sp., A. serlceus n. sp. and A. thoracopunctatus n. sp. Three species removed from Chalcolepldlus Eschscholtz, 1829, are transferred to this genus: A. allcll (Pjatakowa, 1941) n. comb., A. haroldl (Candèze, 1878) n.comb. and A. unlcus (Fleutiaux, 1910) n. comb. The characters of external morphology of these seven species and male and female genitalia, when available, are described and illustrated. An identification key for all species of the genus is included: A. allcll (Pjatakowa, 1941) n. comb., A. calcarlpllosus Casari, 1996, A. cinnamomeus n. sp., A. haroldl (Candèze, 1878) n. comb., A. latlpennls n. sp., A. lusclosus (Hope, 1832), A. melanops Leconte, 1863, A. myops (Fabricius, 1801), A. nobllls Sallé, 1855, A. oculatus (Linnaeus, 1758), A. patrlclus (Candèze, 1857), A. plebejus Candèze, 1874, A. serlceus n. sp., A. thoracopunctatus n. sp., A. tricolor (Olivier, 1790), A. unlcus (Fleutiaux, 1910) n. comb., A. veracruzanus Casari, 1996 and A. zunianus Casey, 1893.  相似文献   

20.

Aquanirmus australis n. sp., from the New Zealand dabchick (Podiceps rufopectus Gray), is described and illustrated. Although showing affinities with both the emersoni and bahli species groups, it is distinguished from the former by the female head length, which is less than 25 % of the total body length, and from the latter by the male terminal tergite, which does not extend beyond the sternal margin.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号