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Matt J. Kessler Barbara Yarbrough Richard G. Rawlins John Berard 《Journal of medical primatology》1984,13(2):57-66
Free-ranging rhesus macaques on the island of Cayo Santiago, Puerto Rico, were surveyed for intestinal parasites for the first time in over 40 years. Results were compared with the only previous study [10], and the relationships between the prevalence of Strongyloides and dominance rank, body weight, age, and matriline examined in the sampled population. 相似文献
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John Berard 《Primates; journal of primatology》1999,40(1):159-175
Considerable controversy exists on the nature of the relationship between male dominance rank and reproductive activity. The
nature of this relationship has important implications for understanding the manner in which males compete for access to limited
resources. Behavioral data on mating patterns were collected over a four-year period from one social group of rhesus macaques
on Cayo Santiago. Correlations between dominance rank and reproductive activity were not stable over a four-year period, but
changed yearly. Positive, significant correlations were present in the first two years of the study while non-significant
correlations were found in the second two years. The variation found in the correlations between rank and mating activity
could be accounted for by changes in the mating frequencies of different classes of males. The long-term resident males had
declines in ejaculation frequencies over the duration of the study. Males who immigrated into the group had yearly increases
in reproductive behavior over three consecutive years. Maturing natal males also increased their levels of reproductive activity
from year-to-year. Combining these mating patterns over time resulted in shifting the proportions of matings away from the
long-term residents and in favor of the new males. High-ranking males had an advantage in reproductive activity over the first
two years of the study, as measured by both the total number of ejaculations and the mean number of ejaculation per male.
New males, comprised of recent immigrants and maturing natal males, had a greater level of reproductive activity over the
last two years. These results suggest that the effect of rank on reproductive activity is variable and that males utilize
alternative tactics to attain access to limited resources. Simple one-factor models explaining the relationship between rank
and reproductive activity must be replaced with models explaining how alternate strategies affect male competition and reproductive
success in primates. 相似文献
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Potential To Reduce Escherichia coli Shedding in Cattle Feces by Using Sainfoin (Onobrychis viciifolia) Forage, Tested In Vitro and In Vivo 下载免费PDF全文
Natalie C. Berard Richard A. Holley Tim A. McAllister Kim H. Ominski Karin M. Wittenberg Kristen S. Bouchard Jenelle J. Bouchard Denis O. Krause 《Applied microbiology》2009,75(4):1074-1079
There is a growing concern about the presence of pathogens in cattle manure and its implications on human and environmental health. The phytochemical-rich forage sainfoin (Onobrychis viciifolia) and purified phenolics (trans-cinnamic acid, p-coumaric acid, and ferulic acid) were evaluated for their ability to reduce the viability of pathogenic Escherichia coli strains, including E. coli O157:H7. MICs were determined using purified phenolics and acetone extracts of sainfoin and alfalfa (Medicago sativa), a non-tannin-containing legume. Ground sainfoin or pure phenolics were mixed with fresh cattle feces and inoculated with a ciprofloxacin-resistant strain of E. coli, O157:H7, to assess its viability at −20°C, 5°C, or 37°C over 14 days. Forty steers were fed either a sainfoin (hay or silage) or alfalfa (hay or silage) diet over a 9-week period. In the in vitro study, the MICs for coumaric (1.2 mg/ml) and cinnamic (1.4 mg/ml) acids were 10- to 20-fold lower than the MICs for sainfoin and alfalfa extracts. In the inoculated feces, the −20°C treatment had death rates which were at least twice as high as those of the 5°C treatment, irrespective of the additive used. Sainfoin was less effective than coumaric acid in reducing E. coli O157:H7 Cipr in the inoculated feces. During the animal trial, fecal E. coli numbers declined marginally in the presence of sainfoin (silage and hay) and alfalfa silage but not in the presence of hay, indicating the presence of other phenolics in alfalfa. In conclusion, phenolic-containing forages can be used as a means of minimally reducing E. coli shedding in cattle without affecting animal production. 相似文献
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The multisolute osmotic virial equation is the only multisolute thermodynamic solution theory that has been derived from first principles and can make predictions of multisolute solution behaviour in the absence of multisolute solution data. Other solution theories either (i) include simplifying assumptions that do not take into account the interactions between different types of solute molecules or (ii) require fitting to multisolute data to obtain empirical parameters. The osmotic virial coefficients, which are obtained from single-solute data, can be used to make predictions of multisolute solution osmolality. The osmotic virial coefficients for a range of solutes of interest in cryobiology are provided in this paper, for use with concentration units of both molality and mole fraction, along with an explanation of the background and theory necessary to implement the multisolute osmotic virial equation. 相似文献