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Male Colobus vellerosus compete intensely for access to females, which sometimes leads to mortal wounding. Yet, males often form cooperative relationships to overtake prime-aged males and immigrate into bisexual groups. We investi...
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Male Colobus vellerosus compete intensely for access to females, which sometimes leads to mortal wounding. Yet, males often form cooperative relationships to overtake prime-aged males and immigrate into bisexual groups. We investigated the factors that predicted the presence of coalitions and affiliative relationships among males in this species. Interactions among males in 292 dyads from six groups were examined from 2004 to 2010 at Boabeng-Fiema, Ghana. Affiliation rates among males were higher and aggression rates lower when one or both males in the dyad were subadult, compared to adult male dyads. Affiliation rates tended to be higher among males that were kin but no other aspect of male relationships predicted affiliation. Coalitions among males were rarely observed and primarily occurred in the context of joint defense against extra-group males (93.5% of events). Adult males were more likely to provide coalitionary support than subadults and coalitions occurred significantly more often when both males were high ranking, since these males probably benefited most in terms of reproductive success from excluding extra-group males. Rank-changing and leveling coalitions among low-ranking males appear to be quite rare or absent in C. vellerosus. The costs of these types of coalitions may be too high or male group size too small on average for these types of coalitions to have been selected for. The overall low rates of affiliation and coalitions among male C. vellerosus are likely influenced by male-biased dispersal and the high level of male male competition.
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The sexual health of young men is often neglected by health care systems that assume healthy developmental trajectories. Clinical morbidities and sexual concerns are not uncommon among sexually emerging young men. Sexually-transmi...
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The sexual health of young men is often neglected by health care systems that assume healthy developmental trajectories. Clinical morbidities and sexual concerns are not uncommon among sexually emerging young men. Sexually-transmitted infections, transient sexual dysfunction and lack of screening for genitourinary abnormalities contribute to this morbidity. This article discusses common sexual issues and concerns of adolescents and young adult men encountered in a clinical practice devoted to men in this age group. The holistic model of care is described. Key issues and updated clinical approaches are discussed. Health care services and education focused on the sexual health of young men improves early detection of disease, prevents morbidity and promotes healthier sexual lifestyles. ? 2009 wpmh GmbH. Published by Elsevier Ireland Ltd.
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摘要 :
The sexual health of young men is often neglected by health care systems that assume healthy developmental trajectories. Clinical morbidities and sexual concerns are not uncommon among sexually emerging young men. Sexually-transmi...
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The sexual health of young men is often neglected by health care systems that assume healthy developmental trajectories. Clinical morbidities and sexual concerns are not uncommon among sexually emerging young men. Sexually-transmitted infections, transient sexual dysfunction and lack of screening for genitourinary abnormalities contribute to this morbidity. This article discusses common sexual issues and concerns of adolescents and young adult men encountered in a clinical practice devoted to men in this age group. The holistic model of care is described. Key issues and updated clinical approaches are discussed. Health care services and education focused on the sexual health of young men improves early detection of disease, prevents morbidity and promotes healthier sexual lifestyles. ? 2009 wpmh GmbH. Published by Elsevier Ireland Ltd.
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Goat does supposedly need to be separated from bucks before male stimuli can induce reproductive activity, ovulation, and estrous. The present study examined the reproductive response (ovulation and estrous) of does to "novel" buc...
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Goat does supposedly need to be separated from bucks before male stimuli can induce reproductive activity, ovulation, and estrous. The present study examined the reproductive response (ovulation and estrous) of does to "novel" bucks in direct contact with them and when separated from them by a fence. One hundred fourteen does were distributed into three groups: (1)ISOL group (N = 31): females that had been completely isolated from males for 46 days, and thereafter placed in direct contact with "novel" males during the breeding period; (2) NOTISOL-CONTACT group (N = 29): females that had been in contact with "familiar" vasectomized males for 46 days and thereafter placed in direct contact with novel males during the breeding period; (3) NOTISOL-NO CONTACT group (N = 54): females that were in contact with familiar vasectomized males for 46 days and thereafter introduced to novel males, but separated by a fence, during the breeding period. All the males were treated with melatonin to ensure that they were sexually active. Estrous activity was recorded daily by direct visual observation of the marks left by marking harnesses worn by the males. Ovulation was confirmed via the plasma progesterone concentration (measured in weekly blood samples). The ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy, and productivity were also determined for the ISOL and NOTISOL-CONTACT groups (naturally, in the NOTISOL-NO CONTACT group, no pregnancies were possible). The introduction of novel males induced the same ovarian response in each group (P > 0.05), but the percentage of females that showed estrous and ovulation was lower in the NOTISOL-NO CONTACT group (P < 0.05). No differences were seen between the ISOL and NOTISOL-CONTACT groups (P > 0.05) in terms of fecundity, fertility, prolificacy, and productivity. These results show that the introduction of novel males to females already in contact with familiar males induces ovarian activity similar to that observed in the classical male effect (ISOL group) and that this response leads to a significantly higher estrus activity only when direct physical contact between the females and the novel males is established. (C) 2014 Elsevier Inc. All rights reserved.
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The aim of this study was to systematically review the evidence for the impact of scrotal cooling on spermatogenesis. EMBASE (1980-2010) and MEDLINE (1950-Sept. 2010) databases were searched using the terms 'male infertility or su...
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The aim of this study was to systematically review the evidence for the impact of scrotal cooling on spermatogenesis. EMBASE (1980-2010) and MEDLINE (1950-Sept. 2010) databases were searched using the terms 'male infertility or subfertility or fertility', combined with a separate search of 'scrotal cooling', without any limits or restrictions. A total of eight articles met the criteria for inclusion in the study. There was insufficient evidence to draw any firm conclusions about the impact of scrotal cooling on male fertility. A positive trend of improved male fertility was however observed. There is therefore a need for well designed randomised controlled trials.
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The derived proportions of the human hand may provide supportive buttressing that protects the hand from injury when striking with a fist. Flexion of digits 2–5 results in buttressing of the pads of the distal phalanges against t...
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The derived proportions of the human hand may provide supportive buttressing that protects the hand from injury when striking with a fist. Flexion of digits 2–5 results in buttressing of the pads of the distal phalanges against the central palm and the palmar pads of the proximal phalanges. Additionally, adduction of the thenar eminence to abut the dorsal surface of the distal phalanges of digits 2 and 3 locks these digits into a solid configuration that may allow a transfer of energy through the thenar eminence to the wrist. To test the hypothesis of a performance advantage, we measured: (1) the forces and rate of change of acceleration (jerk) from maximum effort strikes of subjects striking with a fist and an open hand; (2) the static stiffness of the second metacarpo-phalangeal (MCP) joint in buttressed and unbuttressed fist postures; and (3) static force transfer from digits 2 and 3 to digit 1 also in buttressed and unbuttressed fist postures. We found that peak forces, force impulses and peak jerk did not differ between the closed fist and open palm strikes. However, the structure of the human fist provides buttressing that increases the stiffness of the second MCP joint by fourfold and, as a result of force transfer through the thenar eminence, more than doubles the ability of the proximal phalanges to transmit ‘punching’ force. Thus, the proportions of the human hand provide a performance advantage when striking with a fist. We propose that the derived proportions of hominin hands reflect, in part, sexual selection to improve fighting performance.
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ObjectivesOne-male social systems are usually characterized by polygyny and reproductive exclusion by a single resident male. Sometimes, however, secondary males join these groups, and this may carry fitness costs and/or benefits ...
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ObjectivesOne-male social systems are usually characterized by polygyny and reproductive exclusion by a single resident male. Sometimes, however, secondary males join these groups, and this may carry fitness costs and/or benefits to the resident male. In hamadryas baboons (Papio hamadryas hamadryas), which live in one-male units (OMUs) with female defense polygyny within a multi-level social system, secondary follower males often reside in OMUs. Our aim here is to examine possible benefits of these secondary males to hamadryas resident males.
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This article presents a radiologic perspective of male infertility. Basic embryologic, anatomic, and physiologic concepts underpinning male reproduction are explained. Common and uncommon abnormalities related to male infertility ...
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This article presents a radiologic perspective of male infertility. Basic embryologic, anatomic, and physiologic concepts underpinning male reproduction are explained. Common and uncommon abnormalities related to male infertility and subfertility are described, with emphasis on imaging findings and management strategies.
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An ecological survey of colonies of Polishesformosanus was conducted on Yoron Island, Kagoshima Pref, southern Japan. Nests and adults collected were inspected in the laboratory. All 16 colonies collected were built on the undersi...
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An ecological survey of colonies of Polishesformosanus was conducted on Yoron Island, Kagoshima Pref, southern Japan. Nests and adults collected were inspected in the laboratory. All 16 colonies collected were built on the undersides of leaves of cycads. The mean height of nest sites was 1.54 m above ground. All 14 colonies in which we successfully determined the sexes of the first brood contained males (larvae, pupae or adults) together with females, an unusual phenomenon in paper wasps. The reasonfor the universal production of males in the first brood is discussed. The possibilities that these males were early males, usual males, or diploid males, are proposed and discussed. One of the 16 colonies had two inseminated foundresses, which implies pleometrotic nest foundation. The large size of this colony suggests some advantage of bigyny in colony development. P. formosanus on Yoron Island provides an excellent opportunity to elucidate the advantages of pleometrotic nest foundation and to answerwhy it is usually uncommon in Japan.
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