Evolutionary history of Salmonella typhi     

Roumagnac P  Weill FX  Dolecek C  Baker S  Brisse S  Chinh NT  Le TA  Acosta CJ  Farrar J  Dougan G  Achtman M 《Science (New York, N.Y.)》2006,314(5803):1301-1304

For microbial pathogens, phylogeographic differentiation seems to be relatively common. However, the neutral population structure of Salmonella enterica serovar Typhi reflects the continued existence of ubiquitous haplotypes over millennia. In contrast, clinical use of fluoroquinolones has yielded at least 15 independent gyrA mutations within a decade and stimulated clonal expansion of haplotype H58 in Asia and Africa. Yet, antibiotic-sensitive strains and haplotypes other than H58 still persist despite selection for antibiotic resistance. Neutral evolution in Typhi appears to reflect the asymptomatic carrier state, and adaptive evolution depends on the rapid transmission of phenotypic changes through acute infections.  相似文献   

Costly punishment across human societies   总被引：1，自引：0，他引：1  

Henrich J  McElreath R  Barr A  Ensminger J  Barrett C  Bolyanatz A  Cardenas JC  Gurven M  Gwako E  Henrich N  Lesorogol C  Marlowe F  Tracer D  Ziker J 《Science (New York, N.Y.)》2006,312(5781):1767-1770

Recent behavioral experiments aimed at understanding the evolutionary foundations of human cooperation have suggested that a willingness to engage in costly punishment, even in one-shot situations, may be part of human psychology and a key element in understanding our sociality. However, because most experiments have been confined to students in industrialized societies, generalizations of these insights to the species have necessarily been tentative. Here, experimental results from 15 diverse populations show that (i) all populations demonstrate some willingness to administer costly punishment as unequal behavior increases, (ii) the magnitude of this punishment varies substantially across populations, and (iii) costly punishment positively covaries with altruistic behavior across populations. These findings are consistent with models of the gene-culture coevolution of human altruism and further sharpen what any theory of human cooperation needs to explain.  相似文献   

Deformation of the Zurich cementless acetabular cup caused by implantation in a canine cadaver model          下载免费PDF全文

Geoffrey D. Panjeton MD  Stanley E. Kim BVSc  MS  Diplomate ACVS  Kelvin Chang PhD  Lindsey S. Palm BS  Peter G. Ifju PhD 《Veterinary surgery : VS》2017,46(3):441-447

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Healing of canine skin incisions made with monopolar electrosurgery versus scalpel blade          下载免费PDF全文

Jacqueline E. Scott BVSc  MANZCVS  Elizabeth A. Swanson DVM  MS  Diplomate ACVS  Jim Cooley DVM  Diplomate ACVP  Emily C. Pearce BS 《Veterinary surgery : VS》2017,46(4):520-529

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Single layer centrifugation of fresh dromedary camel semen improves sperm quality and in vitro fertilization capacity compared with simple sperm washing          下载免费PDF全文

C Malo  EG Crichton  JM Morrell  BS Pukazhenthi  JA Skidmore 《Reproduction in domestic animals》2017,52(6):1097-1103

Single layer centrifugation (SLC) through a colloid is a tool for selecting viable mammalian spermatozoa but has not been used previously for fresh dromedary camel sperm. Semen from six camels (2 ejaculates/male) was diluted 1:5 (v:v) or 1:10 (v:v) in a Tris–citrate–fructose buffer for mechanical liquefaction by gentle pipetting. Following liquefaction, semen was processed either by SLC or by centrifugation without a colloid (control). Total and progressive motilities, CASA kinematics, vitality and acrosome integrity (eosin–nigrosin) and plasma membrane integrity (Hypo‐osmotic swelling test; HOST), and fertilizing ability in a heterologous assay (zona‐free goat oocytes) were evaluated. Both total (p = .003) and progressive motilities (p = .003) were higher in SLC‐processed than in control semen samples, irrespective of dilution. Positive HOST values increased when using colloid in 1:5 (p = .001) and 1:10 dilution (p = .010). Colloid‐selected sperm had higher penetration rates than controls (p < .001 and p = .02 for 1:5 and 1:10 dilutions, respectively). However, only the SLC sperm at 1:5 dilution showed higher percentages of pronuclear formation (p = .02) than controls. Dilution effect was only significant for total motility before in vitro fertilization, with higher values for the 1:5 dilution (p = .033). The recovery rates of motile sperm between dilutions were similar (26.1% vs 35.4%; p = .226). In conclusion, SLC is a promising tool for selecting functional dromedary camel sperm and warrants more research.  相似文献   

Correction to: Incidence and characterization of the presence of phytoplasmas in Fraxinus uhdei related with Ash Yellow disease in Colombia     

Filgueira  Juan Jose  Ávila  Kelly Johanna  López  Karen Roció  Mugno  Paula Andrea  Zambrano  Juan Camilo  Cruz  Ana Milena  Villamil-Garzón  Luz Angela  Cruz-Jiménez  Adriana Milena 《植物病害和植物保护杂志》2018,125(5):515-515

Journal of Plant Diseases and Protection - In the article mentioned above, an author’s name was misspelled.  相似文献   

Thyroxine concentrations are elevated in mares which continue to exhibit estrous cycles during the nonbreeding season     

B.P. Fitzgerald BSc  PhD  L.A. Davison BS  MS 《Journal of Equine Veterinary Science》1998,18(1):48-51

In two successive years, the pattern of secretion of thyroxine was compared in seasonally anestrous mares and a subpopulation of mares that exhibited estrous cycles during the nonbreeding season. Blood samples were collected two or three times per week between October and April from a total of 15 mares that exhibited estrous cycles during the nonbreeding season and 21 anestrous mares. Monthly mean concentrations of thyroxine during the period from October through April were greater (p<0.05) in cycling versus anestrous mares. However, it remains to be determined whether continuation of estrous cycles during the nonbreeding season and elevated concentrations of thyroxine are causally related.  相似文献