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Although the supply of physicians in the United States has doubled during the past 20 years, there is still disagreement as to whether we currently have or should expect a significant surplus of physicians. The evidence suggests that despite the rapid expansion in the pool of available physicians, serious physician shortages persist for certain rural populations, ethnic and occupational groups, and other medically disadvantaged segments of the population. Medical students'' declining interest in rural practice and primary care specialties suggests that problems of geographic and specialty maldistribution may worsen despite a rising population of physicians. It is unlikely that a significant physician surplus will develop unless there is a conscious attempt to limit the proportion of national wealth expended on medical care. Pockets of shortage can be reduced by broadening the availability of health insurance, lessening large income disparities between different specialties, changing the way teaching institutions are reimbursed for their training costs, and supporting direct governmental service programs such as the National Health Service Corps. 相似文献
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William Bains 《Bioscience Hypotheses》2009,2(3):115-117
The need to publish ideas so that they can be explored, debated and extended by others before they are fully tested in the lab or the clinic is in conflict with the need to patent those ideas to provide a commercial incentive to apply them. I discuss why this conflict occurs, why it is important, and suggest three ways to get round it: root-and-branch reform of patent law (which seems impossible), extension of the US system's ‘grace period’ between publishing and filing a patent to longer times in the US and implementing the same system in other countries (which seems unlikely to happen), and binding readers of journals with a network of optional confidentiality agreements that allow publication but not citation without the authors’ permission. This latter appears too complex and conflicting an idea to work either, but while many conflicts with common scientific practice exist, the complexity of the system need not deter us, as at root the idea is simple and so it could be managed by software instead of patent lawyers. 相似文献
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Emil Hadač 《Folia Geobotanica》1986,21(3):329-330
It is suggested to add to Walter's “two dimensional” (temperature-precipitation) climatograms a third dimension, i.e. the daylength and sunshine variation. 相似文献
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The conditioned behavior to visual stimuli was obtained in Achatina fulica mollusk on the basis of its negative phototaxis. Directional moving of snails toward black cards was accompanied by the negative unconditioned stimulation (electric current). Learning was expressed in a statistically significant decrease in locomotor activity of animals and decrease in the rate of preference of sections with black cards. Learning developed within two daily training sessions with 30 trials in each of them. Learning traces were observed as defensive behavior at least during a month after reinforcement elimination. 相似文献
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Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
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Peter Godfrey-SmithEmail: |
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Hane Htut Maung 《Bioethics》2019,33(1):43-53
Claims about whether or not infertility is a disease are sometimes invoked to defend or criticize the provision of state‐funded treatment for infertility. In this paper, I suggest that this strategy is problematic. By exploring infertility through key approaches to disease in the philosophy of medicine, I show that there are deep theoretical disagreements regarding what subtypes of infertility qualify as diseases. Given that infertility’s disease status remains unclear, one cannot uncontroversially justify or undermine its claim to medical treatment by claiming that it is or is not a disease. Instead of focusing on disease status, a preferable strategy to approach the debate about state‐funded treatment is to explicitly address the specific ethical considerations raised by infertility. I show how this alternative strategy can be supported by a recent theoretical framework in the philosophy of medicine which avoids the problems associated with the concepts of health and disease. 相似文献
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The heat-shock protein 90 (Hsp90) is currently thought to buffer eukaryotic cells against perturbations caused by pre-existing
cryptic genetic variation. A new study suggests that the buffering function of Hsp90 could instead be due to its repression
of de novo transposon-mediated mutagenesis. 相似文献
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Recently, the focus of conservation efforts gradually changed from a species-centred approach to a broader ambition of conserving functional ecosystems. This new approach relies on the understanding that much ecosystem function is a result of the interaction of species to form complex interaction networks. Therefore measures summarising holistic attributes of such ecological networks have the potential to provide useful indicators to guide and assess conservation objectives. The most generally accepted insight is that complexity in species interactions, measured by network connectance, is an important attribute of healthy communities which usually protects them from secondary extinctions. An implicit and overlooked corollary to this generalization is that conservation efforts should be directed to conserve highly connected communities. We conducted a literature review to search for empirical evidence of a relationship between connectance (complexity) and conservation value (communities on different stages of degradation). Our results show that the often assumed positive relationship between highly connected and desirable (i.e. with high conservation value) communities does not derive from empirical data and that the topic deserves further discussion. Given the conflicting empirical evidence revealed in this study, it is clear that connectance on its own cannot provide clear information about conservation value. In the face of the ongoing biodiversity crisis, studies of species interaction networks should incorporate the different ‘conservation value’ of nodes (i.e. species) in a network if it is to be of practical use in guiding and evaluating conservation practice. 相似文献
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Is it better to combine predictions? 总被引:2,自引:0,他引:2
King RD Ouali M Strong AT Aly A Elmaghraby A Kantardzic M Page D 《Protein engineering》2000,13(1):15-19
We have compared the accuracy of the individual protein secondary structure prediction methods: PHD, DSC, NNSSP and Predator against the accuracy obtained by combing the predictions of the methods. A range of ways of combing predictions were tested: voting, biased voting, linear discrimination, neural networks and decision trees. The combined methods that involve 'learning' (the non-voting methods) were trained using a set of 496 non-homologous domains; this dataset was biased as some of the secondary structure prediction methods had used them for training. We used two independent test sets to compare predictions: the first consisted of 17 non-homologous domains from CASP3 (Third Community Wide Experiment on the Critical Assessment of Techniques for Protein Structure Prediction); the second set consisted of 405 domains that were selected in the same way as the training set, and were non-homologous to each other and the training set. On both test datasets the most accurate individual method was NNSSP, then PHD, DSC and the least accurate was Predator; however, it was not possible to conclusively show a significant difference between the individual methods. Comparing the accuracy of the single methods with that obtained by combing predictions it was found that it was better to use a combination of predictions. On both test datasets it was possible to obtain a approximately 3% improvement in accuracy by combing predictions. In most cases the combined methods were statistically significantly better (at P = 0.05 on the CASP3 test set, and P = 0.01 on the EBI test set). On the CASP3 test dataset there was no significant difference in accuracy between any of the combined method of prediction: on the EBI test dataset, linear discrimination and neural networks significantly outperformed voting techniques. We conclude that it is better to combine predictions. 相似文献
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Duo Li 《中国科学:生命科学英文版》2018,(3)
正High carbohydrate(CHO)intake was associated with higher risk of total mortality,whereas high intake of total fat and individual types of fat were related to lower total mortality.Total fat and types of fat were not associated with cardiovascular disease,myocardial infarction,or cardiovascu- 相似文献
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Insertional mutagenesis resulting in a leukaemia-like lymphoproliferative disease, as observed in the X-SCID (severe combined immunodeficiency) clinical trial using a gamma-retroviral vector that transferred a functional copy of the defective gene into hematopoietic precursor cells of affected children, sparked a debate about a ban on conventional gamma-retroviral vectors. This commentary summarizes the relevant data on this topic and concludes that there is no preclinical or clinical evidence as yet that SIN vectors, which self-inactivate the retroviral long terminal repeats (LTRs), will indeed show an improved safety profile. Conventional murine leukaemia virus (MLV) vectors can thus be used further in clinical gene therapy trials but require a thorough case-by-case risk-benefit analysis. 相似文献