207 research outputs found

    Signature of selection on the rhodopsin gene in the marine radiation of American seven-spined gobies (Gobiidae, Gobiosomatini)

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    In comparison with terrestrial and freshwater ecosystems, information about speciation modes and the role of selection in marine environments is scarce. Recent studies have indicated that spectral adaptation could play an important role in the diversification of marine species flocks. Natural selection influences specific amino acids (AAs) that are involved in the spectral tuning mechanism of visual pigment genes. To study the wider occurrence and the characteristics of spectral adaptation in marine radiations, a reinterpretation of the rhodopsin (RH1) data of American seven-spined gobies (genus Elacatinus; Gobiidae; Teleostei) was carried out. Reanalysis revealed that some AAs, which are well known in the literature as spectral tuning sites, are variable in Elacatinus. Those crucial AA substitutions originated polyphyletically, indicating convergent evolution within the genus Elacatinus. Moreover, statistical tests based on the dN/dS ratio detected selection in several phylogenetic lineages and at specific AAs. Many of these AAs were previously shown to be under selection in other marine radiations. Therefore, the current phylogenetic approach provided an extended list of AAs that are probably involved in spectral tuning, and which should be validated by mutagenic experiments

    Attempted Diastereoselective Preparation and Chiroptical Properties of (2S)-1-(3-Mercapto-2-Methyl-1-Oxopropyl)-L-Proline (Captopril) and Some Congeners

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    CD and 13C-NMRstudy of the eonformational properties of (2S)-1-(3-mercapto-2-methyl-1-oxopropyl)-L-proline (captopril, 1), and its congeners 2-5, 8, 9 is reported. 13C-NMRdata (in DMSO-d6) reveal an E/Z (cis/trans) ratio of ea. (15-30) : (70-85) for the N-acetyl-prolines 1, 5, 10, and for N-acetyl-L-proline. CD data indicate practically identical conformations for the ring systems of 8 and 9. Attempted diastereoselective cyclization of the sodium salt of 7 or the free thioacid into 8 and 9 resulted in low chemical yields (-30%) and low diastereoselectivity, favouring formation of the »wrong- diastereomer 9 in small excess (-20%)

    Understanding global patterns of domestic cannabis cultivation

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    Purpose – Unlike other plant-based drugs, cannabis is increasingly grown within the country of consumption, requires minimal processing before consumption, and can be easily grown almost anywhere using indoor or outdoor cultivation techniques. Developments in agronomic technologies have led to global growth in domestic cultivation, both by cannabis users for self- and social-supply, and by more commercially-oriented growers. Cross-national research is needed to better understand who is involved in domestic cultivation, the diversity in cultivation practices and motivations, and cultivators’ interaction with the criminal justice system and cannabis control policies. Design/methodology/approach – The article introduces the Global Cannabis Cultivation Research Consortium (GCCRC), describes its evolution and aims, and outlines the methodology of its ongoing cross-national online survey of cannabis cultivation. Findings – Despite differing national contexts, the GCCRC successfully developed a core questionnaire to be used in different countries. It accommodates varying research interests through the addition of optional survey sections. The benefits to forming an international consortium to conduct web-based survey research include the sharing of expertise, recruitment efforts and problem-solving. Research limitations/implications – The article discusses the limitations of using non-representative online sampling and the strategies used to increase validity. Originality/value – The GCCRC is conducting the largest cross-national study of domestic cannabis cultivation to date. The aim is not only to better understand patterns of cannabis cultivation and how they differ between countries but also to build upon online engagement methodology with hidden populations

    Growing medicine: Small-scale cannabis cultivation for medical purposes in six different countries

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    Background: The production and consumption of cannabis for the treatment of medical conditions is of increasing importance internationally; however, research on different aspects of the phenomenon is still scarce. In this article, we report findings from a cross-cultural study of small-scale cannabis cultivation for medical purposes. This kind of comparative study has not been done previously. Methods: The data were gathered with a help of web surveys conducted by the Global Cannabis Cultivation Research Consortium (GCCRC) in Australia, Belgium, Denmark, Finland, Germany and the UK (N = 5313). In the analysis we compare reports of medical motives, for what conditions cannabis is used, whether users have diagnoses for these conditions and whether the use of cannabis been recommended as a treatment of those conditions by a medical doctor. Descriptive statistics are used to show the main commonalities and noteworthy disparities across different countries. Results: Findings from countries were quite similar, even though several national differences in details were found. Growing cannabis for medical purposes was widespread. The majority of medical growers reported cultivating cannabis for serious conditions. Most of them did have a formal diagnosis. One fifth had got a recommendation from their doctor, but in most cases cannabis use was self-medication which was not discussed with their doctors. Conclusion: There is a wider demand for licit access for medical cannabis than currently available in these countries. Ideologically, medical growers can be seen distancing themselves from both the legal and illicit drug markets. From a harm reduction perspective, it is worrying that, in the context of present health and control policies in these countries, many medical growers are using cannabis to treat serious medical conditions without proper medical advice and doctor's guidance

    Acceptability with general orderings

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    We present a new approach to termination analysis of logic programs. The essence of the approach is that we make use of general orderings (instead of level mappings), like it is done in transformational approaches to logic program termination analysis, but we apply these orderings directly to the logic program and not to the term-rewrite system obtained through some transformation. We define some variants of acceptability, based on general orderings, and show how they are equivalent to LD-termination. We develop a demand driven, constraint-based approach to verify these acceptability-variants. The advantage of the approach over standard acceptability is that in some cases, where complex level mappings are needed, fairly simple orderings may be easily generated. The advantage over transformational approaches is that it avoids the transformation step all together. {\bf Keywords:} termination analysis, acceptability, orderings.Comment: To appear in "Computational Logic: From Logic Programming into the Future

    The challenges and benefits of analyzing feedback comments in surveys: Lessons from a cross-national online survey of small-scale cannabis growers

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    It is common practice in survey questionnaires to include a general open and non-directive feedback question at the end, but the analysis of this type of data is rarely discussed in the methodological literature. While these open-ended comments can be useful, most researchers fail to report on this issue. The aim of this article is to illustrate and reflect upon the benefits and challenges of analyzing responses to open-ended feedback questions. The article describes the experiences of coding and analyzing data generated through a feedback question at the end of an international online survey with small-scale cannabis cultivators carried out by the Global Cannabis Cultivation Research Consortium. After describing the design and dataset of the web survey, the analytical approach and coding frame are presented. The analytical strategies chosen in this study illustrate the diversity and complexity of feedback comments which pose methodological challenges to researchers wishing to use them for data analyses. In this article, three types of feedback comments (political/policy comments, general comments of positive and negative appreciation, and methodological comments) are used to illustrate the difficulties and advantages of analyzing this type of data. The advantages of analyzing feedback comments are well known, but they seem to be rarely exploited. General feedback questions at the end of surveys are typically non-directive. If researchers want to use these data for research and analyses, they need a clear strategy. They ought to give enough thought to why they are including this type of question, and develop an analytical strategy at the design stage of the study

    The Dutch Y-chromosomal landscape

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    Previous studies indicated existing, albeit limited, genetic-geographic population substructure in the Dutch population based on genome-wide data and a lack of this for mitochondrial SNP based data. Despite the aforementioned studies, Y-chromosomal SNP data from the Netherlands remain scarce and do not cover the territory of the Netherlands well enough to allow a reliable investigation of genetic-geographic population substructure. Here we provide the first substantial dataset of detailed spatial Y-chromosomal haplogroup information in 2085 males collected across the Netherlands and supplemented with previously published data from northern Belgium. We found Y-chromosomal evidence for genetic-geographic population substructure, and several Y-haplogroups demonstrating significant clinal frequency distributions in different directions. By means of prediction surface maps we could visualize (complex) distribution patterns of individual Y-haplogroups in detail. These results highlight the value of a micro-geographic approach and are of great use for forensic and epidemiological investigations and our understanding of the Dutch population history. Moreover, the previously noted absence of genetic-geographic population substructure in the Netherlands based on mitochondrial DNA in contrast to our Y-chromosome results, hints at different population histories for women and men in the Netherlands.Molecular Technology and Informatics for Personalised Medicine and Healt

    Curves of Placental Weights of Live-Born Twins

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    The purpose of this study is to present curves of estimated placental growth in twins and to evaluate the relative contribution of gestational age, zygosity, chorionicity, fusion of the placentas, sex of the individual and of the twin pair, site of the umbilical cord insertion, birth order, maternal age, and parity. Perinatal data and placental data were obtained from 6315 live-born twin pairs from the East Flanders Prospective Twin Survey. Of 4318 twin pairs, with no missing values, the placental weights of different gestational ages were analyzed using a nonlinear multivariate Gaussian regression. Two groups were distinguished: (1) twins with two separate placentas, and (2) twins with only one placental mass (one placenta in case of monochorionic twins or two fused placentas in case of dichorionic placentas). Overall, placental weight was influenced by gestational age, fusion of the placentas, and parity. In the case of one placental mass, monozygotic dichorionic twins had the lowest weights. If two separate placentas were present, birth order played a role in favor of the first-born twin. For parity and zygosity, the differences were most pronounced between 27 and 29 weeks, whereas the difference for birth order was most pronounced between 33 and 37 weeks. In conclusion, basic physiological characteristics, routinely examined at birth, influence placental weight. Taking these covariates into account allows a better evaluation of the placental weight given a gestational age, as an indicator of growth
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