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101.
Zootherapy is the treatment of human ailments with remedies made from animals and their products. Despite its prevalence in traditional medical practices worldwide, research on this phenomenon has often been neglected in comparison to medicinal plant research. This review discusses some related aspects of the use of animal-based remedies in Latin America, identifies those species used as folk remedies, and discusses the implications of zootherapy for public health and biological conservation. The review of literature revealed that at least 584 animal species, distributed in 13 taxonomic categories, have been used in traditional medicine in region. The number of medicinal species catalogued was quite expansive and demonstrates the importance of zootherapy as an alternative mode of therapy in Latin America. Nevertheless, this number is certainly underestimated since the number of studies on the theme are very limited. Animals provide the raw materials for remedies prescribed clinically and are also used in the form of amulets and charms in magic-religious rituals and ceremonies. Zootherapeutic resources were used to treat different diseases. The medicinal fauna is largely based on wild animals, including some endangered species. Besides being influenced by cultural aspects, the relations between humans and biodiversity in the form of zootherapeutic practices are conditioned by the social and economic relations between humans themselves. Further ethnopharmacological studies are necessary to increase our understanding of the links between traditional uses of faunistic resources and conservation biology, public health policies, sustainable management of natural resources and bio-prospecting.  相似文献   
102.
The value of using characters from multiple sources – chromosomes, ecology, gene sequences, and morphology – to evaluate the species status of closely related black flies is demonstrated for three European members of the Simulium vernum group: Simulium crenobium (Knoz, 1961), Simulium juxtacrenobium Bass & Brockhouse, 1990, and Simulium vernum s.s. Macquart, 1826. Simulium juxtacrenobium is a chromosomally, molecularly, and morphologically distinct species that diverged from S. crenobium and S. vernum s.s. about 2 Mya. It is specialized for intermittent streams, is univoltine, and is recorded for the first time from northern Europe, based on collections from Finland and Sweden, representing a range extension of about 1800 km. In contrast, S. crenobium, although confirmed as a distinct species, differs from S. vernum s.s. by only a few larval and chromosomal characters, and by a breeding habitat restricted to mountain spring brooks. Whereas all four character sets independently support the specific distinctness of S. juxtacrenobium and S. vernum s.s., multiple character sets are required to establish the specific validity of S. crenobium.  相似文献   
103.

Background

A large number of studies have been carried out to obtain amino acid propensities for ??-helices and ??-sheets. The obtained propensities for ??-helices are consistent with each other, and the pair-wise correlation coefficient is frequently high. On the other hand, the ??-sheet propensities obtained by several studies differed significantly, indicating that the context significantly affects ??-sheet propensity.

Results

We calculated amino acid propensities for ??-helices and ??-sheets for 39 and 24 protein folds, respectively, and addressed whether they correlate with the fold. The propensities were also calculated for exposed and buried sites, respectively. Results showed that ??-helix propensities do not differ significantly by fold, but ??-sheet propensities are diverse and depend on the fold. The propensities calculated for exposed sites and buried sites are similar for ??-helix, but such is not the case for the ??-sheet propensities. We also found some fold dependence on amino acid frequency in ??-strands. Folds with a high Ser, Thr and Asn content at exposed sites in ??-strands tend to have a low Leu, Ile, Glu, Lys and Arg content (correlation coefficient = ?0.90) and to have flat ??-sheets. At buried sites in ??-strands, the content of Tyr, Trp, Gln and Ser correlates negatively with the content of Val, Ile and Leu (correlation coefficient = ?0.93). "All-??" proteins tend to have a higher content of Tyr, Trp, Gln and Ser, whereas "??/??" proteins tend to have a higher content of Val, Ile and Leu.

Conclusions

The ??-helix propensities are similar for all folds and for exposed and buried residues. However, ??-sheet propensities calculated for exposed residues differ from those for buried residues, indicating that the exposed-residue fraction is one of the major factors governing amino acid composition in ??-strands. Furthermore, the correlations we detected suggest that amino acid composition is related to folding properties such as the twist of a ??-strand or association between two ?? sheets.  相似文献   
104.
105.
1. This study presents a new approach to modelling subsurface irradiance using concepts from survival and failure time analysis. The model applies a modified Weibull distribution function to predict downwelling irradiance. Data sets from forty-seven Norwegian sites show extremely high coefficients of determination, up to 99.99%, when analysed by the Weibull model.
2. The uncritical use of a single k d value to model underwater light conditions is likely to result in poor estimates of received irradiance. This error may amount to several hundred per cent. The practice of force-fitting linear least-squares regressions to log-transformed irradiance data inevitably leads to highly biased estimates of the true fraction of incident irradiance entering the water.
3. Wave effects causing fluctuations of subsurface irradiance are modelled with synthetic data and compared with field observations. Fluctuations of surface elevation by waves produce skewed frequency distributions of the underwater light field. The result of these effects, which are to reduce the accuracy of estimated model parameters, can be largely eliminated by carefully designing field procedures used for the acquisition of subsurface light data.  相似文献   
106.
Ontogenetic allometries (heterauxesis according to Huxley) of about 50 Carboniferous goniatite species from Germany, Spain and USA have been studied by means of geometrical measurements of shell cross sections. They indicate changes of proportions during ontogeny between coiling spiral, umbilical spiral, and whorl width. The allometry constants change suddenly at defined stages. Thus the ontogenetic growth pattern is polyphase, each phase being determined by a different allometric formula.
Ontogenetische Allometrien wurden bei etwa 50 karbonischen Goniatiten-Arten aus Deutschland, Spanien und USA an Hand von Gehäuse-Querschnitten untersucht. Während der Ontogenese erfolgen mehrfach Proportionsverschie-bungen der äußeren Spirale, der Nabelspirale und der Windungsbreite, die sich durch scharfen Wechsel von Allometrie-Konstanten an definierten Stellen aus-drücken. Das Gehäusewachstum erfolgt somit in mehreren Phasen, die von unterschiedlichen Allometrieformeln bestimmt sind.  相似文献   
107.
The seasonal changes in the relative distribution of P700 chlorophyll-protein complex a1 and light harvesting chlorophyll-protein complex a/b were studied in a natural stand of Pinus silvestris. Similar measurements were made after artificial photobleaching of chlorophyll in pine seedlings or in isolated pine chloroplasts. The chlorophyll-protein complexes were solubilized by sodium dodecyl sulphate and separated by polyacrylamide gel electrophoresis. When autumn and winter destruction of chlorophyll occurs, the chlorophyll a antenna associated with P700 in photosystem 1 (P700-CPa1) is relatively more affected than the light harvesting complex, which lacks a reaction centre. These results are further supported by low-temperature fluorescence emission properties of isolated chloroplasts presented in this work and elsewhere. The destruction of chlorophyll in stressing autumn and winter climates is most probably caused by photosensitized oxidation of chlorophyll.  相似文献   
108.
In this investigation, we have collected family-structured data from a partly self-compatible, outcrossing population of Brassica cretica to estimate and compare the effects of one-generation selfing on different types of characters. Inbreeding not only depressed characters that should be positively correlated with fitness irrespective of habitat, e.g. germinability, leaf number and inflorescence size, but also resulted in later flowering, smaller and more asymmetric flowers, and an increased production of basal branches. Population-level estimates of inbreeding depression were similar in magnitude to estimates reported in other wild plant species. There was a tendency for direct components of fitness to exhibit a stronger response to inbreeding than other characters, but only when the differences between selfed and outbred offspring were measured in standard deviation units. Family-level estimates of inbreeding depression were weakly correlated across characters. Given these and other observations, we hypothesize that the genetic basis of inbreeding depression varies across the life cycle and that changes in local inbreeding will lead to shifts in the mean phenotypes of B. cretica populations. However, judging from data on current levels of population divergence, quite large changes in inbreeding will be required to influence large-scale patterns of variation in this species.  © 2002 The Linnean Society of London. Biological Journal of the Linnean Society , 2002, 76 , 317–325.  相似文献   
109.
Career choice is a complex decision in a student''s life. The opportunity to participate in dental education in many countries, especially in the developing ones, is limited to a small percentage of the community. There is a wide range of options for students to choose as a career in general family, gender, personal interest; outcome expectancies can affect the decision in choosing it. Many studies showed that many individuals find themselves in occupations not really knowing why they made that particular decision. The changing nature of the dental workforce and the need to retain the services of future members has made it important to understand why current dental students have chosen dentistry as their career. However, the choice of dentistry becomes forceful at times by peer pressure, cultural thrust or inability to procure medicine. It is of interest to evaluate dentistry as a prospective career choice in India. The participants answered a questionnaire based online survey and the results were collected and analysed statistically. Analyses of data from the survey shows that majority (36.72%) of students had chosen dentistry as a career choice having missed entry or selection into medicine.  相似文献   
110.
The circumpolar arctic fox Alopex lagopus thrives in cold climates and has a high migration rate involving long-distance movements. Thus, it differs from many temperate taxa that were subjected to cyclical restriction in glacial refugia during the Ice Ages. We investigated population history and genetic structure through mitochondrial control region variation in 191 arctic foxes from throughout the arctic. Several haplotypes had a Holarctic distribution and no phylogeographical structure was found. Furthermore, there was no difference in haplotype diversity between populations inhabiting previously glaciated and unglaciated regions. This suggests current gene flow among the studied populations, with the exception of those in Iceland, which is surrounded by year-round open water. Arctic foxes have often been separated into two ecotypes: 'lemming' and 'coastal'. An analysis of molecular variance suggested particularly high gene flow among populations of the 'lemming' ecotype. This could be explained by their higher migration rate and reduced fitness in migrants between ecotypes. A mismatch analysis indicated a sudden expansion in population size around 118 000 BP, which coincides with the last interglacial. We propose that glacial cycles affected the arctic fox in a way opposite to their effect on temperate species, with interglacials leading to short-term isolation in northern refugia.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 79–89.  相似文献   
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