811 research outputs found

    Animal movements in the Kenya Rift and evidence for the earliest ambush hunting by hominins

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    Animal movements in the Kenya Rift Valley today are influenced by a combination of topography and trace nutrient distribution. These patterns would have been the same in the past when hominins inhabited the area. We use this approach to create a landscape reconstruction of Olorgesailie, a key site in the East African Rift with abundant evidence of large-mammal butchery between ~1.2 and ~0.5 Ma BP. The site location in relation to limited animal routes through the area show that hominins were aware of animal movements and used the location for ambush hunting during the Lower to Middle Pleistocene. These features explain the importance of Olorgesailie as a preferred location of repeated hominin activity through multiple changes in climate and local environmental conditions, and provide insights into the cognitive and hunting abilities of Homo erectus while indicating that their activities at the site were aimed at hunting, rather than scavenging

    Genital tract abnormalities among female sex workers who douche with Lemon/Lime juice in Nigeria

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    Vaginal douche products have been associated with cervical cancer. We examined female sex workers (FSWs) in Nigeria who douche with lemon or lime juice and compared the findings with that of nonusers. We obtained Pap smears and performed colposcopy of the vulva, vagina and cervix. A total of 374 FSWs comprising 81 Lemon users (LUs) and 293 non lemon users (NLUs) were examined. Their mean age was 27.8 ± 6.7 (range 16-63) years. At colposcopy, 17(4.5%) had genital warts [LUs 5(6.2%); NLUs 12(4.1%); p=0.43], 61(16.3%) had suspectedsquamous intraepithelial lesions (SILs) [LUs 17(21.0%); NLUs 44(15.0%); p=0.20] and 65(17.4%) had other findings. Pap smear cytology showed that 87(24.6%) had SILs [LUs 26(33.3%); NLUs 61(22.1%); p=0.03]. Lemon/lime use was associated with cervical dysplasia after controlling for HIV status (Adjusted OR=1.8; 95% CI,1.0-3.0). Our data suggests an association between the practice of douching with citrus juice and cervical dysplasia (Afr J Reprod Health 2009; 13[1]:37-45)

    The acheulean handaxe : More like a bird's song than a beatles' tune?

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    © 2016 Wiley Periodicals, Inc. KV is supported by the Netherlands Organization for Scientific Research. MC is supported by the Canada Research Chairs Program, the Social Sciences and Humanities Research of Canada, the Canada Foundation for Innovation, the British Columbia Knowledge Development Fund, and Simon Fraser UniversityPeer reviewedPublisher PD

    Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions

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    During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastroph

    Transdermal microconduits by microscission for drug delivery and sample acquisition

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    BACKGROUND: Painless, rapid, controlled, minimally invasive molecular transport across human skin for drug delivery and analyte acquisition is of widespread interest. Creation of microconduits through the stratum corneum and epidermis is achieved by stochastic scissioning events localized to typically 250 μm diameter areas of human skin in vivo. METHODS: Microscissioning is achieved by a limited flux of accelerated gas: 25 μm inert particles passing through the aperture in a mask held against the stratum corneum. The particles scize (cut) tissue, which is removed by the gas flow with the sensation of a gentle stream of air against the skin. The resulting microconduit is fully open and may be between 50 and 200 μm deep. RESULTS: In vivo adult human tests show that microconduits reduce the electrical impedance between two ECG electrodes from approximately 4,000 Ω to 500 Ω. Drug delivery has been demonstrated in vivo by applying lidocaine to a microconduit from a cotton swab. Sharp point probing demonstrated full anaesthesia around the site within three minutes. Topical application without the microconduit required approximately 1.5 hours. Approximately 180 μm deep microconduits in vivo yielded blood sample volumes of several μl, with a faint pricking sensation as blood enters tissue. Blood glucose measurements were taken with two commercial monitoring systems. Microconduits are invisible to the unaided eye, developing a slight erythematous macule that disappears over days. CONCLUSION: Microscissioned microconduits may provide a minimally invasive basis for delivery of any size molecule, and for extraction of interstitial fluid and blood samples. Such microconduits reduce through-skin electrical impedance, have controllable diameter and depth, are fully open and, after healing, no foreign bodies were visible using through-skin confocal microscopy. In subjects to date, microscissioning is painless and rapid

    Expression of Msx1 and Dlx1 during Dumbo rat head development: Correlation with morphological features

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    The Dumbo rat possesses some characteristics that evoke several human syndromes, such as Treacher-Collins: shortness of the maxillary, zygomatic and mandibular bones, and low position of the ears. Knowing that many homeobox genes are candidates in craniofacial development, we investigated the involvement of the Msx1 and Dlx1 genes in the Dumbo phenotype with the aim of understanding their possible role in abnormal craniofacial morphogenesis and examining the possibility of using Dumbo rat as an experimental model for understanding abnormal craniofacial development. We studied the expression of these genes during craniofacial morphogenesis by RT-PCR method. We used Dumbo embryos at E12 and E14 and included the Wistar strain as a control. Semi-quantitative PCR analysis demonstrated that Msx1 and Dlx1 are expressed differently between Dumbo and Wistar rats, indicating that their low expression may underly the Dumbo phenotype

    Human impact on the hydroenvironment of Lake Parishan, SW Iran, through the late Holocene

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    A multiproxy record from Lake Parishan, SW Iran, shows human impact on the lake and its catchment over the last 4000 years. The Parishan record provides evidence of changes in lake hydrology, from ostracod, diatom and isotope analyses, that are directly linked to human activity in the catchment; recorded by pollen and charcoal and supported by regional archaeological and historical data. The lake ostracod fauna is particularly sensitive to human induced catchment alterations and allow us to identify changes in catchment hydrology that are due to more than a simple change in precipitation: evaporation state. Oxygen isotope data from endogenic carbonates follow these faunal changes but also displays a longer trend to more positive values through the period, coincident with regional patterns of water balance for the late Holocene in the eastern Mediterranean
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