4,247 research outputs found
Social rank overrides environmental and community fluctuations in determining meat access by female chimpanzees in the Taï National Park, Côte d’Ivoire
Meat, long hypothesized as an important food source in human evolution, is still a substantial component of the modern human diet, with some humans relying entirely on meat during certain times of the year. Understanding the socio-ecological context leading to the successful acquisition and consumption of meat by chimpanzees (Pan troglodytes), our closest living relative, can provide insight into the emergence of this trait because humans and chimpanzees are unusual among primates in that they both (i) hunt mammalian prey, (ii) share meat with community members, and (iii) form long-term relationships and complex social hierarchies within their communities. However, females in both human hunter-gatherer societies as well as chimpanzee groups rarely hunt, instead typically accessing meat via males that share meat with group members. In general, female chimpanzee dominance rank affects feeding competition, but so far, the effect of female dominance rank on meat access found different results within and across studied chimpanzee groups. Here we contribute to the debate on how female rank influences meat access while controlling for several socio-ecological variables. Multivariate analyses of 773 separate meat-eating events collected over more than 25 years from two chimpanzee communities located in the Taï National Park, Côte d’Ivoire, were used to test the importance of female dominance rank for being present at, and for acquiring meat, during meat-eating events. We found that high-ranking females were more likely to be present during a meat-eating event and, in addition, were more likely to eat meat compared to the subordinates. These findings were robust to both large demographic changes (decrease of community size) and seasonal ecological changes (fruit abundance dynamics). In addition to social rank, we found that other female properties had a positive influence on presence to meat-eating events and access to meat given presence, including oestrus status, nursing of a small infant, and age. Similar to findings in other chimpanzee populations, our results suggest that females reliably acquire meat over their lifetime despite rarely being active hunters. The implication of this study supports the hypothesis that dominance rank is an important female chimpanzee property conferring benefits for the high-ranking females
Diffuse somatostatin-immunoreactive D-cell hyperplasia in the stomach and duodenum
This paper presents the first case of extensive, diffuse, somatostatin- immunoreactive D-cell hyperplasia in the human stomach and duodenum. It occurred in a 37-yr-old woman, who showed clinical signs of dwarfism, obesity, dryness of the mouth, and goiter. The density of the distribution of D cells was increased 39-fold in the stomach fundus, 23- fold in the proximal antrum, 25-fold in the distal antrum, and 31-fold in the upper duodenum in comparison with normal values. At the same time, the gastrin-immunoreactive cells were increased 2.3-fold in the antrum. Although the range in size of the D cells was within normal limits in all regions examined, the G cells showed pronounced hypertrophy of up to 127%. A possible relationship between the immuno- histochemical findings and the clinical picture is discussed
Young Stars with SALT
We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77
systems. All are low-proper-motion southern hemisphere objects and were
identified in a nearby star survey with a demonstrated sensitivity to young
stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph
(RSS) on the South African Large Telescope (SALT), we have determined radial
velocities, H-alpha, Lithium 6708\AA, and Potassium 7699\AA~equivalent widths
linked to age and activity, and spectral types for all our targets. Combined
with astrometric information from literature sources, we identify 44 young
stars. Eighteen are previously known members of moving groups within 100
parsecs of the Sun. Twelve are new members, including one member of the TW
Hydra moving group, one member of the 32 Orionis moving group, nine members of
Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We
also find fourteen young star systems that are not members of any known groups.
The remaining 33 star systems do not appear to be young. This appears to be
evidence of a new population of nearby young stars not related to the known
nearby young moving groups.Comment: 23 pages, 11 figures, 6 tables. Accepted to Ap
The Potential of Polyhydroxyalkanoate Production from Food Wastes
Background and objective: Over 1 billion tons of foods are wasted every year (not consumed by humans or animals). Most of this waste ends up in landfills. As the global population increases, mankind must look for more sustainable means of living. A recently popular idea is the use of organic wastes as carbon feedstocks for fermentation that produces value added products. Polyhydroxyalkanoates are a family of bio-based, biodegradable polymers that can be produced in large quantities using food and food processing wastes as the main feedstocks. In many cases, biocatalysts have been engineered to efficiently use these waste compounds to produce large quantities of useful intracellular polyhydroxyalkanoates.Results and conclusion: In the current study, various polyhydroxyalkanoates were produced; each with different thermal and mechanical characteristics useful for different applications. If polyhydroxyalkanoate production facilities are established next to food waste accumulation sites (e.g., large landfills), potentials for the economical and sustainable polyhydroxyalkanoate production sound promising.Conflict of interest: The authors declare no conflict of interest
Quantum point contact conductance in NINS junctions
The effect of an insulating barrier located at a distance from a NS
quantum point contact is analyzed in this work. The Bogoliubov de Gennes
equations are solved for NINS junctions (S: anysotropic superconductor, I:
insulator and N: normal metal), where the NIN region is a quantum wire. For , bound states and resonances in the differential conductance are
predicted. These resonances depend on the symmetry of the pair potential, the
strength of the insulating barrier and . Our results show that in a NINS
quantum point contact the number of resonances vary with the symmetry of the
order parameter. This is to be contrasted with the results for the NINS
junction, in which only the position of the resonances changes with the
symmetry.Comment: 5 pages, 5 Figures, RevTex
Understanding of the phase transformation from fullerite to amorphous carbon at the microscopic level
We have studied the shock-induced phase transition from fullerite to a dense
amorphous carbon phase by tight-binding molecular dynamics. For increasing
hydrostatic pressures P, the C60-cages are found to polymerise at P<10 GPa, to
break at P~40 GPa and to slowly collapse further at P>60 GPa. By contrast, in
the presence of additional shear stresses, the cages are destroyed at much
lower pressures (P<30 GPa). We explain this fact in terms of a continuum model,
the snap-through instability of a spherical shell. Surprisingly, the relaxed
high-density structures display no intermediate-range order.Comment: 5 pages, 3 figure
Clinical use of CCR5 inhibitors in HIV and beyond
Since the discovery of CCR5 as a coreceptor for HIV entry, there has been interest in blockade of the receptor for treatment and prevention of HIV infection. Although several CCR5 antagonists have been evaluated in clinical trials, only maraviroc has been approved for clinical use in the treatment of HIV-infected patients. The efficacy, safety and resistance profile of CCR5 antagonists with a focus on maraviroc are reviewed here along with their usage in special and emerging clinical situations. Despite being approved for use since 2007, the optimal use of maraviroc has yet to be well-defined in HIV and potentially in other diseases. Maraviroc and other CCR5 antagonists have the potential for use in a variety of other clinical situations such as the prevention of HIV transmission, intensification of HIV treatment and prevention of rejection in organ transplantation. The use of CCR5 antagonists may be potentiated by other agents such as rapamycin which downregulate CCR5 receptors thus decreasing CCR5 density. There may even be a role for their use in combination with other entry inhibitors. However, clinical use of CCR5 antagonists may have negative consequences in diseases such as West Nile and Tick-borne encephalitis virus infections. In summary, CCR5 antagonists have great therapeutic potential in the treatment and prevention of HIV as well as future use in novel situations such as organ transplantation. Their optimal use either alone or in combination with other agents will be defined by further investigation
Pengaruh Penyuluhan Kesehatan Terhadap Kesiapsiagaan Menghadapi Bencana Gempa Bumi Pada Siswa SMP Kristen Kakaskasen Kota Tomohon
Gempa bumi termasuk bencana alam yang paling dahsyat. Indonesia merupakan negara kepulauan yang terletak pada pertemuan empat lempeng tektonik yang sangat berpotensi sekaligus rawan bencana gempa bumi. Kurangnya pengetahuan dan kesiapan mengakibatkan timbulnya banyak korban, dimana paling banyak korban bencana gempa bumi adalah wanita dan anak-anak. Jarak SMP Kristen begitu dekat dengan gunung Lokon (kurang dari 5 km) yang masih aktif, mengakibatkan sekolah selalu menerima dampak gempa bumi sebelum gunung meletus berupa korban luka, kecemasan, dan terganggunya proses belajar. Tujuan untuk Mengetahui Pengaruh Penyuluhan Kesehatan Terhadap Kesiapsiagaan Menghadapi Bencana Gempa Bumi Pada Siswa SMP Kristen Kakaskasen Kota Tomohon. Sampel berjumlah 60 responden dengan menggunakan teknik probability sampling. Desain penelitian yaitu one group pre-post test dan menggunakan lembar kuesioner untuk mendapatkan data dari responden. Hasil Penelitian menggunakan uji statistik Wilcoxon didapat nilai P-value sebesar 0,00 (< = 0,05). Kesimpulan menunjukkan adanya pengaruh penyuluhan kesehatan terhadap kesiapsiagaan menghadapi bencana gempa bumi pada siswa SMP Kristen Kakaskasen Kota Tomohon. Saran agar pihak sekolah lebih giat melaksanakan pendidikan kesehatan khususnya kesiapsiagaan menghadapi bencana serta untuk peneliti selanjutnya, kiranya dapat meneliti mengenai faktor-faktor lain yang dapat meningkatkan kesiapsiagaan menghadapi bencana
Effect of temperature and illumination on the electrical characteristics of polymer-fullerene bulk-heterojunction solar cells
The current-voltage characteristics of ITO/PEDOT:PSS/OC1C10-PPV:PCBM/Al solar cells were measured in the temperature range 125-320 K under variable illumination, between 0.03 and 100 mW cm(-2) (white light), with the aim of determining the efficiency-limiting mechanism(s) in these devices, and the temperature and/or illumination range(s) in which these devices demonstrate optimal performance. (ITO: indium tin oxide; PEDOT:PSS: poly(styrene sulfonate)-doped poly(ethylene dioxythiophene); OC1C10-PPV: poly[2-methoxy-5-(3,7-dimethyl octyloxy)-1,4-phenylene vinylene]; PCBM: phenyl-C-61 butyric acid methyl ester.) The short-circuit current density and the fill factor grow monotonically with temperature until 320 K. This is indicative of a thermally activated transport of photogenerated charge carriers, influenced by recombination with shallow traps. A gradual increase of the open-circuit voltage to 0.91 V was observed upon cooling the devices down to 125 K. This fits the picture in which the open-circuit voltage is not limited by the work-function difference of electrode materials used. The overall effect of temperature on solar-cell parameters results in a positive temperature coefficient of the power conversion efficiency, which is 1.9% at T = 320 K and 100 mW cm(-2) (2.5% at 0.7 mW cm(-2)). The almost-linear variation of the short-circuit current density with light intensity confirms that the internal recombination losses are predominantly of monomolecular type under short-circuit conditions. We present evidence that the efficiency of this type of solar cell is limited by a light-dependent shunt resistance. Furthermore, the electronic transport properties of the absorber materials, e.g., low effective charge-carrier mobility with a strong temperature dependence, limit the photogenerated current due to a high series resistance, therefore the active layer thickness must be kept low, which results in low absorption for this particular composite absorber
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