406 research outputs found

    Tool use behavior in three wild bonobo communities at Kokolopori

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    Abstract Comparative studies on tool technologies in extant primates, especially in our closest living relatives, offer a window into the evolutionary foundations of tool use in hominins. Whereas chimpanzee tool technology is well studied across populations, the scarcity of described tool technology in wild populations of our other closest living relative, the bonobo, is a mystery. Here we provide a first report of the tool use repertoire of the Kokolopori bonobos and describe in detail the use of leaf-umbrellas during rainfall, with the aim to improve our knowledge of bonobo tool use capacity in the wild. The tool use repertoire of the Kokolopori bonobos was most similar to that of the nearby population of Wamba and comprised eight behaviors, none in a foraging context. Further, over a 6-month period we documented 44 instances of leaf-umbrella use by 22 individuals from three communities, suggesting that this behavior is habitual. Most leaf-umbrella tool users were adult females, and we observed a nonadult using a leaf-umbrella on only a single occasion. While the study and theory of tool technologies is often based on the use of tools in foraging tasks, tool use in bonobos typically occurs in nonforaging contexts across populations. Therefore, incorporating both foraging and nonforaging contexts into our theoretical framework is essential if we wish to advance our understanding of the evolutionary trajectories of tool technology in humans

    Antioxidant properties of MitoTEMPOL and its hydroxylamine

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    Piperidine nitroxides such as TEMPOL have been widely used as antioxidants in vitro and in vivo. MitoTEMPOL is a mitochondria-targeted derivative of TEMPOL designed to protect mitochondria from the oxidative damage that they accumulate, but once there is rapidly reduced to its hydroxylamine, MitoTEMPOL-H. As little is known about the antioxidant efficacy of hydroxylamines, this study has assessed the antioxidant activity of both MitoTEMPOL and MitoTEMPOL-H. The hydroxylamine was more effective at preventing lipid-peroxidation than MitoTEMPOL and decreased oxidative damage to mitochondrial DNA caused by menadione. In contrast to MitoTEMPOL, MitoTEMPOL-H has no superoxide dismutase activity and its antioxidant actions are likely to be mediated by hydrogen atom donation. Therefore, even though MitoTEMPOL is rapidly reduced to MitoTEMPOL-H in cells, it remains an effective antioxidant. Furthermore, as TEMPOL is also reduced to a hydroxylamine in vivo, many of its antioxidant effects may also be mediated by its hydroxylamine

    Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore

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    Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous

    Long-term repeatability in social behaviour suggests stable social phenotypes in wild chimpanzees

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    Consistent individual differences in social phenotypes have been observed in many animal species. Changes in demographics, dominance hierarchies or ecological factors, such as food availability or disease prevalence, are expected to influence decision-making processes regarding social interactions. Therefore, it should be expected that individuals show flexibility rather than stability in social behaviour over time to maximize the fitness benefits of social living. Understanding the processes that create and maintain social phenotypes requires data encompassing a range of socioecological settings and variation in intrinsic state or life-history stage or strategy. Using observational data spanning up to 19 years for some individuals, we demonstrate that multiple types of social behaviour are repeatable over the long term in wild chimpanzees, a long-lived species with complex fission-fusion societies. We controlled for temporal, ecological and demographic changes, limiting pseudo-repeatability. We conclude that chimpanzees living in natural ecological settings have relatively stable long-term social phenotypes over years that may be independent of life-history or reproductive strategies. Our results add to the growing body of the literature suggesting consistent individual differences in social tendencies are more likely the rule rather than the exception in group-living animals

    Chimpanzee identification and social network construction through an online citizen science platform

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    Abstract Citizen science has grown rapidly in popularity in recent years due to its potential to educate and engage the public while providing a means to address a myriad of scientific questions. However, the rise in popularity of citizen science has also been accompanied by concerns about the quality of data emerging from citizen science research projects. We assessed data quality in the online citizen scientist platform Chimp&See, which hosts camera trap videos of chimpanzees (Pan troglodytes) and other species across Equatorial Africa. In particular, we compared detection and identification of individual chimpanzees by citizen scientists with that of experts with years of experience studying those chimpanzees. We found that citizen scientists typically detected the same number of individual chimpanzees as experts, but assigned far fewer identifications (IDs) to those individuals. Those IDs assigned, however, were nearly always in agreement with the IDs provided by experts. We applied the data sets of citizen scientists and experts by constructing social networks from each. We found that both social networks were relatively robust and shared a similar structure, as well as having positively correlated individual network positions. Our findings demonstrate that, although citizen scientists produced a smaller data set based on fewer confirmed IDs, the data strongly reflect expert classifications and can be used for meaningful assessments of group structure and dynamics. This approach expands opportunities for social research and conservation monitoring in great apes and many other individually identifiable species

    Penelitian pengaplikasian ciri-ciri keselamatan kemudahan penginapan homestay patuh syariah di destinasi pilihan pelancong di Sabah dan kaitannya dengan maqasid syariah

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    Industri pelancongan sangat sinonim dengan pelbagai aktiviti menarik seperti mengembara ke destinasi indah, mempelajari kebudayaan masyarakat, membeli-belah serta merasai pengalaman melakukan aktiviti sukan dan rekreasi yang ekstrem. Pelancong dalam negeri dan antarabangsa sentiasa terdedah risiko persekitaran yang dinamik disebabkan oleh tindakan manusia mahupun bencana alam semulajadi. Pelbagai aspek perlu diambil kira dalam memastikan keselamatan sentiasa terpelihara saat melancong ke destinasi yang asing bagi para pelancong seperti pemilihan kemudahan penginapan. Dewasa kini, penginapan jenis homestay semakin mendapat tempat dalam kalangan pelancong terutamanya pelancong domestik. Justeru, kertas kerja ini cuba meneliti ciri-ciri asas yang disediakan oleh pengusaha homestay dalam memastikan keselamatan penginapan terjamin dengan baik. Selain itu, penyediaan kemudahan penginapan homestay patuh syariah perlu menekankan aspek keselamatan yang perlu merujuk perspektif maqasid syariah kerana ianya mempunyai kepentingan yang tersendiri dalam mengukur dan mempertimbangkan sesuatu perkara demi menjamin kemaslahatan dan menolak keburukan. Pertimbangan yang menjadi kayu pengukur ini semestinya berlandaskan kepada nilai-nilai al-Quran dan al-Sunnah yang menjadi asas bagi memastikan ianya berada di dalam kerangka syariat. Penelitian ciri-ciri keselamatan ini juga adalah indikator baru yang dimasukkan dalam ciri-ciri kemudahan homestay patuh syariah selain reka bentuk dan ruang persekitaran (bilik), organisasi dan kakitangan penginapan, etika pelanggan atau penginap dan kemudahan awam yang sedang giat dilaksanakan di tiga destinasi tumpuan pelancong di Sabah iaitu Kota Kinabalu, Kundasang dan Semporna. Kajian ini melibatkan tiga puluh (30) orang pengusaha homestay yang aktif dan penelitian dilaksanakan berpandukan kepada soal selidik serta senarai semak ciri-ciri kemudahan homestay patuh syariah yang disediakan. Hasil analisis mendapati enam daripada tujuh ciri-ciri keselamatan iaitu penyediaan pagar keselamatan, alat pemadam kebakaran, pengurusan sisa pepejal yang sistematik, ruang merokok (khas), persekitaran yang bebas semak samun dan ancaman binatang berbisa dan kit pertolongan cemas yang diteliti mencapai tahap pengaplikasian yang tinggi di homestay yang terlibat kecuali pemasangan kamera litar tertutup di kawasan homestay

    Domain formation in DODAB–cholesterol mixed systems monitored via nile red anisotropy

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    The effect of the cholesterol (Ch) on liposomes composed of the cationic lipid dioctadecyldimethylammonium bromide (DODAB) was assessed by studying both the steady-state and time-resolved fluorescence anisotropy of the dye Nile Red. The information obtained combined with analysis of the steady-state emission and luorescence lifetime of Nile Red (NR) for different cholesterol concentrations (5–50%) elucidated the presence of “condensed complexes” and cholesterol-rich domains in these mixed systems. The steady-state fluorescence spectra were decomposed into the sum of two lognormal emissions, emanating from two different states, and the effect of temperature on the anisotropy decay of Nile Red for different cholesterol concentrations was observed. At room temperature, the time-resolved anisotropy decays are indicative of NR being relatively immobile (manifest by a high r∞ value). At higher temperature, rotational times ca. 1 ns were obtained throughout and a trend in increasing hindrance was seen with increase of Ch content

    Mesenchymal Stromal Cells Improve Salivary Function and Reduce Lymphocytic Infiltrates in Mice with Sjögren's-Like Disease

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    Non-obese diabetic (NOD) mice develop Sjögren's-like disease (SS-like) with loss of saliva flow and increased lymphocytic infiltrates in salivary glands (SGs). There are recent reports using multipotent mesenchymal stromal cells (MSCs) as a therapeutic strategy for autoimmune diseases due to their anti-inflammatory and immunomodulatory capabilities. This paper proposed a combined immuno- and cell-based therapy consisting of: A) an injection of complete Freund's adjuvant (CFA) to eradicate autoreactive T lymphocytes, and B) transplantations of MSCs to reselect lymphocytes. The objective of this was to test the effectiveness of CD45(-)/TER119(-) cells (MSCs) in re-establishing salivary function and in reducing the number of lymphocytic infiltrates (foci) in SGs. The second objective was to study if the mechanisms underlying a decrease in inflammation (focus score) was due to CFA, MSCs, or CFA+MSCs combined.Donor MSCs were isolated from bones of male transgenic eGFP mice. Eight week-old female NOD mice received one of the following treatments: insulin, CFA, MSC, or CFA+MSC (combined therapy). Mice were followed for 14 weeks post-therapy. CD45(-)/TER119(-) cells demonstrated characteristics of MSCs as they were positive for Sca-1, CD106, CD105, CD73, CD29, CD44, negative for CD45, TER119, CD11b, had high number of CFU-F, and differentiated into osteocytes, chondrocytes and adipocytes. Both MSC and MSC+CFA groups prevented loss of saliva flow and reduced lymphocytic infiltrations in SGs. Moreover, the influx of T and B cells decreased in all foci in MSC and MSC+CFA groups, while the frequency of Foxp3(+) (T(reg)) cell was increased. MSC-therapy alone reduced inflammation (TNF-α, TGF-β), but the combination of MSC+CFA reduced inflammation and increased the regenerative potential of SGs (FGF-2, EGF).The combined use of MSC+CFA was effective in both preventing saliva secretion loss and reducing lymphocytic influx in salivary glands
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