86 research outputs found

    From covalent bonding to coalescence of metallic nanorods

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    Growth of metallic nanorods by physical vapor deposition is a common practice, and the origin of their dimensions is a characteristic length scale that depends on the three-dimensional Ehrlich-Schwoebel (3D ES) barrier. For most metals, the 3D ES barrier is large so the characteristic length scale is on the order of 200 nm. Using density functional theory-based ab initio calculations, this paper reports that the 3D ES barrier of Al is small, making it infeasible to grow Al nanorods. By analyzing electron density distributions, this paper shows that the small barrier is the result of covalent bonding in Al. Beyond the infeasibility of growing Al nanorods by physical vapor deposition, the results of this paper suggest a new mechanism of controlling the 3D ES barrier and thereby nanorod growth. The modification of local degree of covalent bonding, for example, via the introduction of surfactants, can increase the 3D ES barrier and promote nanorod growth, or decrease the 3D ES barrier and promote thin film growth

    Living knowledge of the healing plants: Ethno-phytotherapy in the Chepang communities from the Mid-Hills of Nepal

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    Contribution of indigenous knowledge in developing more effective drugs with minimum or no side effects helped to realise importance of study of indigenous remedies and the conservation of biological resources. This study analysed indigenous knowledge regarding medicinal plants use among the Chepang communities from ward number 3 and 4 of Shaktikhor Village Development Committee located in the central mid hills of Nepal. Data were collected in a one-year period and included interviews with traditional healers and elders. Chepangs are rich in knowledge regarding use of different plants and were using a total 219 plant parts from 115 species including one mushroom (belonging 55 families) for medicinal uses. Out of these, 75 species had 118 different new medicinal uses and 18 of them were not reported in any previous documents from Nepal as medicinal plants. Spiritual belief, economy and limitation of alternative health facilities were cause of continuity of people's dependency on traditional healers. Change in socio-economic activities not only threatened traditional knowledge but also resource base of the area. Enforcement of local institution in management of forest resources and legitimating traditional knowledge and practices could help to preserve indigenous knowledge

    Combined Effects of Legumes with Rock Phosphorus on Rice in West Africa

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    Rice (Oryza sativa L.) demand in West Africa is unmet because of insufficient production. Legume fixed N [biological N fixation (BNF)] may sustainably increase rice productivity in low-input systems. However, P deficiency limits BNF on the acid soils encountered in the region, despite the prevalence of phosphate rock (PR). Pot and field experiments were conducted in Cîte d'Ivoire in 1996–1998 to study the impact of combined legume and PR on rice performance. Triple superphosphate and PR were applied at rates of 60 (pot) and at 90 (field) kg P ha−1 to rice and the legume Aeschynomene afraspera grown for 8 wk and then incorporated before rice transplanting. Legume fixed N was determined by 15N isotope dilution. Under field conditions, addition of PR doubled the biomass of A. afraspera Irrespective of P source, P application increased the amount of BNF-N (three- to eightfold) to 36 mg N plant−l in pots and to 84 kg N ha−1 in the field. Nitrogen derived from the air was correlated with legume P uptake (r = 0.97***, where *** = significant at the 0.001 level) and nodulation (r = 0.91**, where ** = significant at the 0.01 level). The synergy of PR and BNF on N and P cycling improved P nutrition and total biomass of subsequent lowland rice under pot conditions. Combining legume green manure (GM) with PR enhanced soil extractable Bray-1 P and may thus play an important role in improving the availability of PR. Under field conditions, due to asynchrony in GM nutrient release and demand, the impact of the combined GM–PR treatment on rice yield was minimal

    Study of 3He(n,p)3H reaction at cosmological energies with trojan horse method

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    In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results

    De la possession dans le droit civil de la province de Québec.

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    Combined two parts into one. No p.134, probably typo.[...] En arrivant au Canada, ma decision etaitprise: j'ecri-rais sur la possession. Cette decision a trouve encore un autre motif de justification, des que j'ai su qu'aucun travail d'ensemble n'existait sur la possession, dans le Droit Civil de la Province de Quebec. Cette circonstance, m'offrait la possibilite de satisfaire mon desir de remplir une lacune dans mon 6duration juridique, en meme temps que de combler, quoique d'une maniere imparfa ite, une lacune dans le bibliographic quebecoise. [...

    Correlates of Cytochrome P450 1A1 Expression in Bottlenose Dolphin (Tursiops truncatus) Integument Biopsies

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    Integument biopsy is a nondestructive method for sampling free-ranging cetaceans, which allows for the determination of both contaminant concentrations and biomarker responses. Cytochrome P450 1A1 (CYP1A1) expression is induced by polycyclic aromatic hydrocarbons and planar halogenated aromatic hydrocarbons such as the non-ortho and mono-ortho polychlorinated biphenyls (PCBs). CYP1A induction has been used extensively as a biomarker of exposure to such compounds in vertebrates. We measured PCB concentrations and CYP1A1 expression in integument biopsies from bottlenose dolphins (Tursiops truncatus) resident in Sarasota Bay, FL. This population of dolphins has been the subject of long-term population and health assessment, affording the opportunity to evaluate the influence of age, sex, and reproductive status on CYP1A1 expression. CYP1A1 expression was seen in endothelial cells, vascular smooth muscle, and nerve cells in the dermis, similar to what has been observed in other cetacean species. Endothelial CYP1A1 expression varied along the length of the biopsy, which could be related to differences in the structure and functionality of the blubber in different parts of the integument. Neither age nor sex was related to CYP1A1 expression in these biopsies, and reproductive status did not relate to levels of CYP1A1 in females. Total PCB and toxic equivalent quotient concentrations in blubber were positively correlated with dermal endothelial CYP1A1 expression, although mono-ortho PCBs concentrations did not show this relationship. Contaminant concentrations appear to be stronger determinants of CYP1A1 expression in integument of these dolphins, than are age, sex, or reproductive status
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