822 research outputs found

    Caperton\u27s Next Generation: Beyond the Bank

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    The article looks at a panel discussion on judicial responsibility and the U.S. Supreme Court\u27s decision in \u27Caperton v. A.T. Massey Coal Co.\u27 discussed by several law professionals including Jed Shugerman, Debra Lyn Bassett and Dmitry Bam at a 2014 symposium held in the New York University

    Grain quality characteristics of imported rice in Ghana: Implications for breeding for consumer-preferred varieties

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    ABSTRACTRice is the fastest growing food source in Ghana. The country, however, imports about 70 per cent of its rice requirement due to low volumes of production and poor grain quality of domestic rice compared to imported ones.  In the study, 10 popular imported rice brands on the Ghanaian market were characterised for grain quality traits including grain dimensions, apparent amylose content, gelatinisation temperature, paste viscosity properties, and aroma using physiochemical properties and DNA markers. The rice brands came from Asia and the USA. The rice type from Asia was found to be Jasmine-styled aromatic long grained with low amylose content and gelatinisation temperature, whereas those of USA were conventional long grain with intermediate amylose content and gelatinisation temperature.  These findings were confirmed through DNA marker analyses, with the rice types from Asia and the USA revealing the presence of the TAC and GCC of the waxy gene SNP haplotypes, respectively. The implication for rice breeding in Ghana is discussed.Original scientific paper. Received 29 Oct. 14; revised 03 Aug 15

    Shape analysis of the StW 578 calotte from Jacovec Cavern, Gauteng (South Africa)

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    The fossiliferous deposits within the lower-lying Jacovec Cavern in the locality of Sterkfontein yielded valuable hominin remains, including the StW 578 specimen. Because StW 578 mainly preserves the calotte, the taxonomic status of this specimen has been a matter of discussion. Within this context, here we employed high-resolution microtomography and a landmark-free registration method to explore taxonomically diagnostic features in the external surface of the StW 578 calotte. Our comparative sample included adult humans and common chimpanzees as well as one Australopithecus africanus specimen (Sts 5). We partially restored the StW 578 calotte digitally and compared it to extant specimens and Sts 5 using a landmark-free registration based on smooth and invertible surface deformation. Our comparative shape analysis reveals morphological differences with extant humans, especially in the frontal bones, and with extant chimpanzees, as well as intriguing specificities in the morphology of the StW 578 parietal bones. Lastly, our study suggests morphological proximity between StW 578 and Sts 5. Given the intimate relationship between the brain and the braincase, as well as the integration of the hominin face and neurocranium, we suggest that cranial vault shape differences between StW 578 and extant humans, if confirmed by further analyses, could be either explained by differences in brain surface morphology or in the face. Besides providing additional information about the morphology of the Jacovec calotte that will be useful in future taxonomic discussion, this study introduces a new protocol for the landmark-free analysis of fossil hominin cranial shape.Significance:• We provide further information on the enigmatic fossil specimen StW 578.• We introduce a new approach for the morphological study of fossil hominin crania.• We highlight morphological similarities between StW 578 and ‘Mrs Ples’

    The repulsive lattice gas, the independent-set polynomial, and the Lov\'asz local lemma

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    We elucidate the close connection between the repulsive lattice gas in equilibrium statistical mechanics and the Lovasz local lemma in probabilistic combinatorics. We show that the conclusion of the Lovasz local lemma holds for dependency graph G and probabilities {p_x} if and only if the independent-set polynomial for G is nonvanishing in the polydisc of radii {p_x}. Furthermore, we show that the usual proof of the Lovasz local lemma -- which provides a sufficient condition for this to occur -- corresponds to a simple inductive argument for the nonvanishing of the independent-set polynomial in a polydisc, which was discovered implicitly by Shearer and explicitly by Dobrushin. We also present some refinements and extensions of both arguments, including a generalization of the Lovasz local lemma that allows for "soft" dependencies. In addition, we prove some general properties of the partition function of a repulsive lattice gas, most of which are consequences of the alternating-sign property for the Mayer coefficients. We conclude with a brief discussion of the repulsive lattice gas on countably infinite graphs.Comment: LaTex2e, 97 pages. Version 2 makes slight changes to improve clarity. To be published in J. Stat. Phy

    Nurturing novelty: Toulmin's greenhouse, journal rankings and the evolution of knowledge

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    Reflecting on Toulmin’s 1972 conceptualization of the academic research process, we fast-forward his thinking to the current climate of academic excellence and associated journal ranking lists. We argue that the formal and informal use of such rankings throughout the hierarchy of research institutions creates an artificial environment within which favoured ‘branches’ of knowledge continue to flourish at the expense of new conceptual saplings. This ‘greenhouse’ effect might result in the creation of a knowledge tree which is increasingly unfit to the external world for which it is intended. We thus step back and examine wider implications of these factors on the broader evolution of knowledge in the research process. In sum, we argue for a Toulminian explanation of the process by which journal ranking lists reduce academic innovation and creativity, bias academic selection and constrain dissemination processes in the academic community

    Determination of Trace Elements in the Sakumo Wetland Sediments

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    Abstract: The objective of this research was to determine the current pollution status of the Sakumo wetland with the aim of identifying factors affecting the long-term integrity of the wetland ecosystem. Sediment samples from the Sakumo wetland were analysed for Cd, Co, Cr, Cu, Fe, Ni, Mn and Zn using Instrumental Neutron Activation Analysis (INAA) coupled with the conventional counting system. The sediment materials exhibited higher concentrations of trace elements Cd (maximum; 0.041 mg/kg), Co (maximum; 0.64 mg/kg), Cr (maximum; 30.73 mg/kg), Cu (maximum; 22.89 mg/kg), Ni (maximum; 11.69 mg/kg) and Zn (maximum; 6.52 mg/kg). In some of the lagoon sediments compared with their levels in world average soils, the average concentrations of the trace elements in general are below or within levels in world average soils/uncontaminated soils. Concentrations of Ni showed positive correlation with Cr whilst Co correlated positively with Cr and Zn. However, lack of correlation between Fe and Cd, suggests that the influence of these parameters on the distribution of trace metals is not important

    Farmers' perceptions on mechanical weeders for rice production in sub-Saharan Africa

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    Competition from weeds is one of the major biophysical constraints to rice (Oryza spp.) production in sub-Saharan Africa. Smallholder rice farmers require efficient, affordable and labour-saving weed management technologies. Mechanical weeders have shown to fit this profile. Several mechanical weeder types exist but little is known about locally specific differences in performance and farmer preference between these types. Three to six different weeder types were evaluated at 10 different sites across seven countries – i.e., Benin, Burkina Faso, Côte d'Ivoire, Ghana, Nigeria, Rwanda and Togo. A total of 310 farmers (173 male, 137 female) tested the weeders, scored them for their preference, and compared them with their own weed management practices. In a follow-up study, 186 farmers from Benin and Nigeria received the ring hoe, which was the most preferred in these two countries, to use it during the entire crop growing season. Farmers were surveyed on their experiences. The probability of the ring hoe having the highest score among the tested weeders was 71%. The probability of farmers’ preference of the ring hoe over their usual practices – i.e., herbicide, traditional hoe and hand weeding – was 52, 95 and 91%, respectively. The preference of this weeder was not related to gender, years of experience with rice cultivation, rice field size, weed infestation level, water status or soil texture. In the follow-up study, 80% of farmers who used the ring hoe indicated that weeding time was reduced by at least 31%. Of the farmers testing the ring hoe in the follow-up study, 35% used it also for other crops such as vegetables, maize, sorghum, cassava and millet. These results suggest that the ring hoe offers a gender-neutral solution for reducing labour for weeding in rice as well as other crops and that it is compatible with a wide range of environments. The implications of our findings and challenges for out-scaling of mechanical weeders are discussed

    MR1 overexpression correlates with poor clinical prognosis in glioma patients

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    Background: Glioblastoma is the most common adult primary brain tumor with near-universal fatality. Major histocompatibility complex (MHC) class I molecules are important mediators of CD8 activation and can be downregulated by cancer cells to escape immune surveillance. MR1 is a nonclassical MHC-I-like molecule responsible for the activation of a subset of T cells. Although high levels of MR1 expression should enhance cancer cell recognition, various tumors demonstrate MR1 overexpression with unknown implications. Here, we study the role of MR1 in glioma. Methods: Using multi-omics data from the Cancer Genome Atlas (TCGA), we studied MR1 expression patterns and its impact on survival for various solid tumors. In glioma specifically, we validated MR1 expression by histology, elucidate transcriptomic profiles of MR1 high versus low gliomas. To understand MR1 expression, we analyzed the methylation status of the MR1 gene and MR1 gene-related transcription factor (TF) expression. Results: MR1 is overexpressed in all grades of glioma and many other solid cancers. However, only in glioma, MR1 overexpression correlated with poor overall survival and demonstrated global dysregulation of many immune-related genes in an MR1-dependent manner. MR1 overexpression correlated with decreased MR1 gene methylation and upregulation of predicted MR1 promoter binding TFs, implying MR1 gene methylation might regulate MR1 expression in glioma. Conclusions: Our in silico analysis shows that MR1 expression is a predictor of clinical outcome in glioma patients and is potentially regulated at the epigenetic level, resulting in immune-related genes dysregulation. These findings need to be validated using independent in vitro and in vivo functional studies

    Impact of Protracted War Crisis on Dental Students: A Comparative Multicountry Cross-sectional Study

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    BACKGROUND: The impact of conflict and war crisis on dental students is poorly understood. Given the prolonged conflicts and political instability in the Arabic-speaking countries, it is crucial to investigate the effect of these conditions on dental students. This study aimed to assess the impact of protracted war on dental students by comparing the personal, university, and wider context challenges they face across war-affected and unaffected countries. METHODS: A cross-sectional study was conducted including a convenience sample of dental students from 13 universities in 12 Arabic-speaking countries. Respondents were those at entry and exit points of their undergraduate dental training. A self-administered paper questionnaire collected anonymized data on sociodemographics, and personal, university, and wider context challenges that students were facing. Multivariable Poisson regression analyses were carried out. RESULTS: The overall response rate was 64.8%. The mean age was 21.2 (standard deviation = 2.1) years, with 68% of participants being female. After adjusting for age and sex, dental students in Arabic-speaking countries affected by protracted war crisis were significantly more likely to report wider context challenges compared to their counterparts in unaffected countries (n = 2448; beta = 1.12; 95% confidence interval: 1.10-1.13; P < 0.001). DISCUSSION: Dental students in Arabic-speaking countries affected by protracted war crisis were more likely to suffer from wider context challenges such as difficulties in attendance due to the deterioration of security and lack of flexibility of teaching time to accommodate the different circumstances induced by the war crisis. Supporting dental students in areas affected by protracted war crises is needed and may include developing online dental education programs
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