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41.
Using combined gas chromatography and mass spectrometry a growth-promoting, organic component of sea water has been quantitatively estimated and identified as the cytokinin 6-(3 methyl-2-butenylamino) purine. Additions of this cytokinin, kinetin or sea water from the Fucus-Ascophyllum zone increased the growth of Ectocarpus confervoides and Pylaiella litoralis in artificial sea water. Additions of kinetin to bacteria-free cultures of Ectocarpus fasciculatus also initiated the production of upright ectocarpoid filaments.  相似文献   
42.
ABSTRACT

We examined the acoustic structure of the calls of 71 species of nestling passerines (both suboscines and oscines) and 4 species of nestling woodpeckers. Calls varied greatly in general acoustic structure, frequency (pitch) and duration. Some phylogenetic trends occurred, e.g. calls of woodpeckers and suboscines tended to be simpler than those of most oscines. Body size was significantly correlated with both maximum and minimum frequency. Age-related changes occurred in some species but not others. The results suggest some phylogenetic and developmental constraints on call structure, but do not rule out the possibility that selection acts directly on nestling calls. However, the hypothesis that cavity-nesters would have more easily localizable calls than open-nesters because of lowered predation risk was not supported by our study, which showed no significant differences in any frequency or temporal measures of acoustic structure between cavity-nesters and open-nesters.  相似文献   
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44.
In 2009 the WPA President established a Task Force that was to examine available evidence about the stigmatization of psychiatry and psychiatrists and to make recommendations about action that national psychiatric societies and psychiatrists as professionals could do to reduce or prevent the stigmatization of their discipline as well as to prevent its nefarious consequences. This paper presents a summary of the Task Force’s findings and recommendations. The Task Force reviewed the literature concerning the image of psychiatry and psychiatrists in the media and the opinions about psychiatry and psychiatrists of the general public, of students of medicine, of health professionals other than psychiatrists and of persons with mental illness and their families. It also reviewed the evidence about the interventions that have been undertaken to combat stigma and consequent discrimination and made a series of recommendations to the national psychiatric societies and to individual psychiatrists. The Task Force laid emphasis on the formulation of best practices of psychiatry and their application in health services and on the revision of curricula for the training of health personnel. It also recommended that national psychiatric societies establish links with other professional associations, with organizations of patients and their relatives and with the media in order to approach the problems of stigma on a broad front. The Task Force also underlined the role that psychiatrists can play in the prevention of stigmatization of psychiatry, stressing the need to develop a respectful relationship with patients, to strictly observe ethical rules in the practice of psychiatry and to maintain professional competence.  相似文献   
45.
Climate change is expected to affect the high latitudes first and most severely, rendering Antarctica one of the most significant baseline environments for the study of global climate change. The indirect effects of climate warming, including changes to the availability of key environmental resources, such as water and nutrients, are likely to have a greater impact upon continental Antarctic terrestrial ecosystems than the effects of fluctuations in temperature alone. To investigate the likely impacts of a wetter climate on Antarctic terrestrial communities a multiseason, manipulative field experiment was conducted in the floristically important Windmill Islands region of East Antarctica. Four cryptogamic communities (pure bryophyte, moribund bryophyte, crustose and fructicose lichen‐dominated) received increased water and/or nutrient additions over two consecutive summer seasons. The increased water approximated an 18% increase in snow melt days (0.2°C increase in temperature), while the nutrient addition of 3.5 g N m?2 yr?1 was within the range of soil N in the vicinity. A range of physiological and biochemical measurements were conducted in order to quantify the community response. While an overall increase in productivity in response to water and nutrient additions was observed, productivity appeared to respond more strongly to nutrient additions than to water additions. Pure bryophyte communities, and lichen communities dominated by the genus Usnea, showed stronger positive responses to nutrient additions, identifying some communities that may be better able to adapt and prosper under the ameliorating conditions associated with a warmer, wetter future climate. Under such a climate, productivity is overall likely to increase but some cryptogamic communities are likely to thrive more than others. Regeneration of moribund bryophytes appears likely only if a future moisture regime creates consistently moist conditions.  相似文献   
46.
The correct identification of colony boundaries is an essential prerequisite for empirical studies of ant behaviour and evolution. Ant colonies function at various organizational levels, and these boundaries may be difficult to assess. Moreover, new complexity can be generated through the presence of spatially discrete subgroups within a more or less genetically homogeneous colony, a situation called polydomy. A colony is polydomous only if individuals (workers and brood) of its constituent nests function as a social and cooperative unit and are regularly interchanged among nests. This condition was previously called polycalic, and the term polydomy was used in a broader sense for a group of daughter nests of the same mother colony (implying limited female dispersal), without regard to whether these different nests continued to exchange individuals. We think that this distinction between ‘polycaly’ and ‘polydomy’ concerns two disparate concepts. We thus prefer the narrower definition of polydomy, which groups individuals that interact socially. Does this new level of organization affect the way in which natural selection acts on social traits? Here, after examining the history of terms, we review all ant species that have been described as expressing polydomous structures. We show that there is no particular syndrome of traits predictably associated with polydomy. We detail the existing theoretical predictions and empirical results on the ecology of polydomy, and the impact of polydomy on social evolution and investment strategies, while carefully distinguishing monogynous from polygynous species. Finally, we propose a methodology for future studies and offer ideas about what remains to be done. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90 , 319–348.  相似文献   
47.
Four plant species (Zea mays, Lolium italicum, Phaseolus vulgaris,and Pisum sativum) were grown either with full nutrient supplyor with calcium, potassium, or nitrogen deficiency. After 4–6weeks the shoots were analysed for their content of K+, Ca2+,Mg2+, and Na+, of total anions, and of organic acids. The qualitativepattern of organic acid components, characteristic of each species,remained, with few exceptions, unchanged by deficiency treatments.Striking differences were detected in the total acid contentand in the quantities of the respective main organic acid components,especially in potassium-deficient plants. These changes showedstrong correlations with alterations of cation excess and demonstratethat aconitate in Zea mays, malonate in Phaseolus vulgaris,and citrate in Pisum sativum contribute to charge balance.  相似文献   
48.
Genetic variability among root voles (Microtus oeconomus [Pallas, 1776]) originating from two distantly separate regions of Norway (Valdres and Finnmark) was studied by DNA fingerprinting using the probes 33.15, 33.6 and M13. All three probes revealed polymorphic, although relatively simple, patterns. DNA fingerprint banding patterns were clearly diagnostic of the animals' region of origin. Notably, Valdres animals display a high molecular-weight cluster of bands not found in Finnmark, reflective of the isolation, and possibly an indication of separate colonization events, of the two groups. On the local level in Finnmark, bands associating with a specific trap site were observed in trappings on consecutive years. Comparisons of Finnmark animals taken at three trap sites at approximately 10 km intervals show a gradient of genetic similarity. Captive bred siblings were also compared, yielding average values significantly higher than those seen from same-site comparisons. We suggest that the sensitivity provided by DNA fingerprinting with multi-locus minisatellite probes is appropriate for population genetic studies in M. oeconomus. Also, because band-sharing correlates to spacing in M. oeconomus, we propose that DNA fingerprinting may be used to study dispersal, recruitment and other population processes in this and possibly other rodent species.  相似文献   
49.
The present study aimed to investigate the morphological and genetic differentiation of lowland and montane populations of the Pieris napi species complex in Norway and to make inferences about the subspecific status of Pieris napi adalwinda and Pieris napi napi . We measured 22 morphological characters on 228 individuals from eight populations in Central Norway (20–1100 m a.s.l.). In addition, lowland and mountain animals were reared at a high altitude locality. Half the animals from either locality were reared on mountain plant, and the other half on a lowland plant. Finally, a fragment of the mitochondrial cytochrome b gene was sequenced for individuals from Central and South-eastern Norway and Germany. Principal component analysis of morphological characters showed a zone of abrupt change from lowland to mountain morphological character states between populations at 506 m and 730 m a.s.l., respectively. The transplant experiment showed that the morphological differences have a genetic basis and that food plants have no impact on morphology. Limited, but significant, molecular genetic differentiation was found between lowland and mountain animals, but the phylogenetic analysis, however, showed that the lowland form ( P. n. napi ) is paraphyletic and the montane form ( P. n. adalwinda ) is monophyletic. Further study is required before taxonomic recognition can be applied.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 727–745.  相似文献   
50.
In the past, practice in mental health was guided by the belief that individuals with serious mental illnesses do not recover. The course of their illness was either seen pessimistically, as deteriorative, or optimistically, as a maintenance course. Research over the past thirty to forty years has indicted that belief and shown that a vision of recovery can be achieved for many individuals. People with serious mental illnesses have themselves published accounts of their own recovery as well as advocated for the development of recovery promoting services. In North America and other regions, policies have been developed to make recovery the guiding vision of services. Today, particularly in the United States, much effort is going into the transformation of services and systems to achieve recovery outcomes. Despite these trends, the idea of recovery remains controversial and, some say, even illusory. This article clarifies the meaning of the term "recovery", reviews the research and first person accounts providing a rationale for recovery, and sets out implications for developing recovery oriented services.  相似文献   
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