首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
In this article, the author analyzes Arthur Efland's Art and Cognition, which advocates study of the visual arts for its cognitive benefits. The author argues that Efland's cognitive premises are largely sound but that his specific recommendations often belie the general principles he espouses. Efland focuses on the interpretation of baffling works that deliberately flout traditional views of what constitutes a work of art. He thereby ignores his own emphasis on the role of categorization in human cognition. Moreover, although he stresses the cognitive importance of individual goals and intentions, Efland favors sociopolitical interpretations. Such interpretations disregard contradictory evidence of the artist's likely intentions and downplay the personal value of art. The author views Efland's emphasis on visual metaphor as inconsistent with his recognition that the visual arts possess a distinctive immediacy and directness.  相似文献   

2.
Dengler ( Journal of Biogeography , 2009, 36 , 728–744) addresses issues regarding species–area relationships (SARs), but fails to settles those issues. He states that only certain types of sampling schemes should be used to construct SARs, but is not consistent in the criteria that he uses to include some sampling schemes but not others. He argues that a sampling scheme of contiguous plots will be more accurate in extrapolating beyond the sampled area, but logic tells us that a dispersed sampling scheme is likely to be more accurate. Finally, he concludes that the 'true' SAR is a power function, but this conclusion is inconsistent with his results and with the results of others. Rather than defining a narrow framework for SARs, we need to recognize that the relationship between area and species richness is scale- and system-dependent. Different sampling schemes serve different purposes, and a variety of functional relationships are likely to hold. Further theoretical and empirical work is needed to resolve these issues fully.  相似文献   

3.
Given the predominance of brachiation and other forms of suspension in gibbon locomotion, we compared the locomotor, postural, and manipulative behaviors of a captive, juvenile, one‐armed gibbon to the behavioral profiles of his family members. We expected Kien Nahn, whose arm was amputated in response to an untreatable injury approximately 1 year before observations began, to avoid suspensory locomotion, to spend more time immobile, and to be less likely to exhibit postures involving forelimb suspension. Data were collected using scan sampling to record the behaviors and postures of Kien Nahn, his younger brother, and his parents. Additional postural and manipulative behaviors were recorded ad lib. Kien Nahn and his younger sibling had similar activity levels, and although differences in postural profiles existed, they were surprisingly few. Specifically, Kien Nahn spent significantly less time in motion and in non‐suspensory forms of locomotion than his brother. When compared to his parents, Kien Nahn was found to be both active and in motion more often, but was less likely to exhibit the forelimb suspension posture. Despite the increased energetic demands associated with one‐armed brachiation, Kien Nahn preferred suspensory locomotion to other forms of locomotion. Furthermore, he found unique solutions for foraging and locomoting, often making use of his feet and teeth, and he was generally the first to approach and manipulate enrichment objects. We found no evidence to suggest that Kien Nahn's injury has altered his activity levels. Although the one‐armed gibbon displayed slightly different locomotor, postural, and manipulative behaviors than his family members, he seems to have adapted well to his injury. Zoo Biol 0:1–8, 2007. © 2007 Wiley‐Liss, Inc.  相似文献   

4.
V. Craig Jordan is a pioneer in the molecular pharmacology and therapeutics of breast cancer. As a teenager, he wanted to develop drugs to treat cancer, but at the time in the 1960s, this was unfashionable. Nevertheless, he saw an opportunity and through his mentors, trained himself to re-invent a failed "morning-after pill" to become tamoxifen, the gold standard for the treatment and prevention of breast cancer. It is estimated that at least a million women worldwide are alive today because of the clinical application of Jordan's laboratory research. Throughout his career, he has always looked at "the good, the bad and the ugly" of tamoxifen. He was the first to raise concerns about the possibility of tamoxifen increasing endometrial cancer. He described selective estrogen receptor modulation (SERM) and he was the first to describe both the bone protective effects and the breast chemopreventive effects of raloxifene. Raloxifene did not increase endometrial cancer and is now used to prevent breast cancer and osteoporosis.The scientific strategy he introduced of using long term therapy for treatment and prevention caused him to study acquired drug resistance to SERMs. He made the paradoxical discovery that physiological estrogen can be used to treat and to prevent breast cancer once exhaustive anti-hormone resistance develops. His philosophy for his four decades of discovery has been to use the conversation between the laboratory and the clinic to improve women's health.  相似文献   

5.
CAIN, A. J., 1994. Rank and sequence in Caspar Bauhin's Pinax. Bauhin's consistent use of genera, species and binominals, applauded by historians as anticipating Linnaeus's theory and practice, does not appear on closer examination to be intended as anything of the sort. His use of the terms genus and species is as in Aristotelian logic, with a shifting reference, at all taxonomic levels. His typographical layout, emphasizing (but far from invariably employing) single-word names for effectively generic entities, often qualified by ‘and its species’, gives the impression of Linnaean practice, and coincides with it not infrequently, but not with Linnaean theory. The main entities for which it can be said that Bauhin uses fairly consistently a biverbal binominal name-phrase, like Linnaeus' trivial names, were in fact in Linnaeus's eyes two levels of supraspecific groupings. The main entities in Bauhin which Linnaeus recognized as species, as is shown by his quotations in the Species plantarum, are subdivisions of his biverbally or nearly biverbally named groupings, but themselves have multiverbal names. These correspond closely to Linnaeus's diagnostic specific names, not at all to his biverbal trivial names. Bauhin probably had no conception of the species and genus as ranks in the modern sense, first adumbrated by Tournefort and utilized by Linnaeus. Bauhin certainly tried to group forms by natural affinity, as did Theophrastus before him and Linnaeus afterwards. Not being alerted to the importance of the details of the flower and fruit, he used what characters he could find, notably, but not by any means exclusively, leaf shape. He composed the Pinax as a nomenclatural concordance to earlier authors, notably Dioscorides, Theophrastus and Pliny. He retained the sequence of major groups of Theophrastus (as the greatest authority on plants) but reversed it to start with the best-known plants, grasses. Where Theophrastus gave no help, in the cryptogams, Bauhin inserted as a pendant his own series from ferns down to fungi, using the Aristotelian principles of the gradation of forms. His overall arrangement, therefore, is not a simple progression but a chain with pendants. Bauhin is far closer to earlier authors than to Linnaeus, but his typography, along with other authors, may well have helped to incite Linnaeus to a more rigorous and consistent use of ranked groups and biverbal names.  相似文献   

6.

Objective

Approximately 10% of young adults report non-medical use of stimulants (cocaine, amphetamine, methylphenidate), which puts them at risk for the development of dependence. This fMRI study investigates whether subjects at early stages of stimulant use show altered decision making processing.

Methods

158 occasional stimulants users (OSU) and 50 comparison subjects (CS) performed a “risky gains” decision making task during which they could select safe options (cash in 20 cents) or gamble them for double or nothing in two consecutive gambles (win or lose 40 or 80 cents, “risky decisions”). The primary analysis focused on risky versus safe decisions. Three secondary analyses were conducted: First, a robust regression examined the effect of lifetime exposure to stimulants and marijuana; second, subgroups of OSU with >1000 (n = 42), or <50 lifetime marijuana uses (n = 32), were compared to CS with <50 lifetime uses (n = 46) to examine potential marijuana effects; third, brain activation associated with behavioral adjustment following monetary losses was probed.

Results

There were no behavioral differences between groups. OSU showed attenuated activation across risky and safe decisions in prefrontal cortex, insula, and dorsal striatum, exhibited lower anterior cingulate cortex (ACC) and dorsal striatum activation for risky decisions and greater inferior frontal gyrus activation for safe decisions. Those OSU with relatively more stimulant use showed greater dorsal ACC and posterior insula attenuation. In comparison, greater lifetime marijuana use was associated with less neural differentiation between risky and safe decisions. OSU who chose more safe responses after losses exhibited similarities with CS relative to those preferring risky options.

Discussion

Individuals at risk for the development of stimulant use disorders presented less differentiated neural processing of risky and safe options. Specifically, OSU show attenuated brain response in regions critical for performance monitoring, reward processing and interoceptive awareness. Marijuana had additive effects by diminishing neural risk differentiation.  相似文献   

7.
Charles Darwin's empirical research in palaeontology, especially on fossil invertebrates, has been relatively neglected as a source of insight into his thinking, other than to note that he viewed the fossil record as very incomplete. During the Beagle voyage, Darwin gained extensive experience with a wide diversity of fossil taxa, and he thought deeply about the nature of the fossil record. That record was, for him, a major source of evidence for large-scale transmutation, but much less so for natural selection or single lineages. Darwin's interpretation of the fossil record has been criticised for its focus on incompleteness, but the record as he knew it was extremely incomplete. He was compelled to address this in arguing for descent with modification, which was likely his primary goal. Darwin's gradualism has been both misrepresented and exaggerated, and has distracted us from the importance of the fossil record in his thinking, which should be viewed in the context of the multiple, sometimes competing demands of the multifaceted argument he presented in the Origin of Species.  相似文献   

8.
Nearly half a century ago, H.T. Odum envisioned a sustainable approach to systems design where human intervention would be supplementary to nature. He referred to this concept as ecological engineering and suggested that practitioners should receive an education beyond the rigors of engineering. To understand natural processes needed to design, develop, and restore natural systems successfully, Odum suggested ecological engineers should have an expanded knowledge of environmental systems and ecology. Furthermore, he recommended broadening educational exposure to social science and liberal arts. The field of ecological engineering has blossomed in the years since Odum expressed his vision, but universities have not adopted his suggested curriculum, and undergraduate engineering students have generally seen a reduction in social science and liberal arts courses. This paper compares Odum's vision with the surveyed visions of an international group of ecological engineers, who assessed the value and characteristics of an ecological engineering undergraduate education. The respondents’ perspectives vary with their location, education, and profession; however, most participants in this survey share Odum's vision, and are dissatisfied with existing curricula. Participants outside of the United States were more confident that something approaching Odum's vision for a program in ecological engineering could be delivered at the undergraduate level.  相似文献   

9.
This study uses data from the National Longitudinal Study of Adolescent Health to examine whether a polymorphism in the serotonin transporter gene (5HTTLPR) moderates the effects of marijuana use on property offending. The results reveal that 5HTTLPR interacts with marijuana use to predict significantly higher levels of property offending for African American females. The interaction coefficient is not statistically significant for Caucasian males, African American males, or Caucasian females. These findings suggest that marijuana use is associated only with higher levels of property offending among African American females who carry one or more copies of the 5HTTLPR short allele.  相似文献   

10.
Conclusion My conclusion is that Mendel deliberately, though without any real falsification, tried to suggest to his audience and readers an unlikely and substantially wrong reconstruction of the first and most important phase of his research. In my book I offer many reasons for this strange and surprising behavior,53 but the main argument rests on the fact of linkage. Mendelian genetics cannot account for linkage because it was based on the idea of applying probability theory to the problem of species evolution. Central to the theory is the law of probability according to which the chance occurrence of a combination of independent events is the product of their separate probabilities. This is the common basis of Mendel's first and second laws, but this is why Mendel's second law on independent assortment is enunciated in too general a way. From Morgan's work we now know that characters may not always be independent if their genes are located very close one to the other on the same chromosome. And this was also the basis of Mendel's personal drama: he surely observed the effects of linkage, but he had no theoretical tools with which to explain it. So he presented his results in a logical structure consistent with the central idea of his theory. Had he described the real course of his experiments he would have had to admit that his law worked for only a few of the hundreds of Pisum characters — and it would thus have been considered more of an exception than a rule. This is why he insisted on the necessity of testing the law on other plants, and this is why in his second letter to Carl Nägeli he admits that the publication of his data was untimely and dangerous.54.We can argue that already in 1866 Mendel was less confident that his so-called second law had the same general validity as the first — and that later he lost his confidence altogether. Contemporary testimony indicates that in the end he became as skeptical as all his contemporaries as to the scientific relevance of his theory.55 But he was wrong. His research is in no way the fruit of methodological mistakes or forgery, and it remains a landmark in the history of science. He was only the victim of a strange destiny in which the use of probability theory was responsible, at the same time, for the strength and for the weakness of his theory. We must still consider him the father and founder of genetics.  相似文献   

11.
Autism is a pervasive developmental disorder characterised by impairment in social interaction and communication, with unusual behavior. In some cases the pharmacotherapy is prescribed and the most studied antipshychotic drugs include haloperidol and risperidone. In this paper we displayed the treatment of two cases of autism in boy and girl with risperidone. With the use of risperidone in girl, we have achieved reduction of psychomotor symptoms and reduction of hetero-aggressive and self-destructive behavior, and in boy we have also achieved reduction of psychomotoric symptoms, with improvement in contact with his surrounding, he had less learning problems and he has felt familiar not only with his mother, but with other persons. Research on the use of risperidone in the treatment of autistic disorders among children in Croatia are rare, given the limited use of risperidone in children younger than 15years, the question arises about the need to expand the scope of application of risperidone in younger age groups.  相似文献   

12.
Linnaeus's artificial and natural arrangements of plants are examined using a Spearman rank coefficient (which is explained) on his presentations of his own and others' arrangements in the Classes plantarum and elsewhere. There is little alteration in his successive artificial arrangements. In contrast, between 1751 and 1764 his natural arrangements changed considerably, partly in the sequences of genera within orders but mostly by rearrangement of the orders. Comparison with Cesalpino's and Ray's natural arrangements, using the longest-recognized natural groups as signposts, suggests that Linnaeus in his latest natural arrangement (1764) approximated more closely to Ray's. Examination of Linnaeus's successive treatments of certain groups (palms, Zingiberaceae, Hydrocharis-Stratiotes-Vallisneria) and of Giseke's exposition of Linnaeus's lectures on natural groups (1792) shows that Linnaeus was much influenced by habitus and vegetative characters as well as those of the fructification. He recognized orders consisting of a chain of genera linked successively by overall affinity and without any single diagnostic character. Where possible, he preferred characters of the fructification and his ‘secret’ consulting of the habitus is explained as secondary to such characters. It is suggested that in his latest arrangement he approximated more to a scala naturae, as he probably did in zoology about the same time. Within his artificial arrangements Linnaeus kept to sequences of genera as natural as possible. He realized that some groups in his natural arrangements were still artificial, and his aphorism that all genera and species are natural, classes and orders part natural and part artificial, refers to his and others' practice until the natural system could be completed. It is not a statement of the essential natures of these ranks. Linnaeus's distinction in practice between natural and artificial arrangements was less clear-cut than Sachs believed. Linnaeus's rejection of the ancient tree/herb division was empirical, not a reasoned repudiation of an a priori grouping. The tree/herb division could be upheld in his day as obviously natural, not merely accepted on authority.  相似文献   

13.
We have been sometimes forced to notice that there are forgotten rupestral arts: until recently, they were only studied by explorers or informed travellers and are rarely reported in the scientific literature. This is in part the case of engravings in the Moroccan High Atlas to which I have devoted my research (Ezziani, 2002, 2004a, 2004b). J Malhomme is among the people who were most invested in their investigation. He spent ten years in noting and collecting a considerable number of engravings: more than one thousand figures dispersed on the sides of the Atlas in places of difficult access at more than 2000 masl. He published many papers about his discoveries, which led to the publication of a remarkable corpus in two parts (Malhomme, 1959-1961). However, this corpus is far from being exhaustive. Recently, A. Rodrigue carried out new and excellent drawings within his research activity (1996). He added to the corpus of Malhomme a large number of figures discovered by A. Simoneau (1967, 1968, 1970), A. Jodin (1964, 1966) (two other researchers who have been closely interested in the High Atlas engravings) and himself, but unfortunately some engravings were damaged: whole flagstones have disappeared, so that the original drawings from Malhomme still remain very useful. All these data constituted the documentation base of my own work. In this paper, first I review some classification methods, then I propose my own and point out the inherent difficulties in this task. I conclude with a proposal for an outline of the structure of the High Atlas engravings.  相似文献   

14.
At age 80, Antony van Leeuwenhoek was a world-famous scientist who came from a prosperous Delft family with a heritage of public service. He continued that tradition by serving in paid municipal offices. Self-taught, he began his scientific career in his 40s, when he began making hundreds of tiny single-lens microscopes. Pioneering the use of now-common microscopic techniques, he was the first human to see microbes and microscopic structures in animals, plants, and minerals. Over 50 years, he wrote only letters, more than 300 of them, and published half of them himself. More than a hundred were published in translation in the Royal Society’s Philosophical Transactions. Today, Leeuwenhoek is considered in the lesser rank of scientists and is not well known outside of his homeland. Recent archival research in Delft has contributed new information about his life that helps to contextualize his science, but much remains to be learned.  相似文献   

15.
We asked 303 practicing physicians in general internal medicine, family medicine, gastroenterology, or psychiatry to indicate whether possessing or using marijuana should be considered a felony, a misdemeanor, warrant the issuance of a citation, or be legalized. The position physicians advocated was unrelated to their specialty, experience diagnosing or treating substance abuse problems, their attitudes toward the efficacy of the treatment of drug abuse, or any other work role or habit we measured. Legalization or citation as compared with harsher penalties, however, was more likely favored by physicians who were younger, less religious, politically more liberal, and those less likely to perceive a serious drug problem in society. Legalization was also more likely favored by physicians who themselves had used marijuana, cocaine, and amphetamines but was unrelated to the use of alcohol, cigarettes, or tranquilizers. Although physician opinion should be sought as society deals with the drug problem, this study suggests how physicians'' characteristics may influence the opinions that are rendered.  相似文献   

16.
Thomas Hunt Morgan taught at Bryn Mawr College from 1891 until1904. During his years there he concentrated his research interestson embryology; he included regeneration as an integral partof development. This article maintains that Morgan did not abandonhis interest in embryology when he became a geneticist at Columbia,but it deals mainly with his teaching and research while atBryn Mawr. He worked on the development of a great diversityof organisms, plant and animal, he used widely differing experimentalmethods to investigate them, and he concerned himself with manydifferent general and special problems. He strove to investigateproblems that were directly soluble by experimental intervention,and was highly critical, in the best possible way, of the experimentsand interpretations made by his contemporaries, who regardedhim as a leader. He exerted his influence on developmental biologynot only through his research, but also through a number offine textbooks, and by his teaching. During his Bryn Mawr yearshe encouraged his students, undergraduate and graduate, to carryout independent research. He sometimes published with them asco-author, but dozens of articles by his students were publishedwithout carrying Morgan's name as co-author.  相似文献   

17.
Speciation and carcinogenesis result from genomic instability at the gametic or at the somatic levels. After an infinity of trials they occur, by chromosome rearrangements, in single individuals or in single cells and evolve by similar chromosomal or clonal evolutions. Loss of heterozygosity for the first event is essential in both processes: in evolution, a chromosomal rearrangement, a pericentric inversion or a Robertsonian fusion, must become homozygous to ensure a reproductive barrier for a new species; Knudson's two-event sequence is a similar situation in cancer. Position effect is equally important: we have shown overexpression of the SOD1 gene in the orangutan phylum probably by an intrachromosomal rearrangement; the t(9;22) in CML acts by typical position effect. Parental imprinting underlies the evolution of genome function and the unset of certain cancers. Evolution and malignancy are interweaved by viruses and oncogenes since the dawn of life. Cancer uses its intelligence to expand and to destroy the other tissues, using subtle metabolic pathways and a variety of tricks to metastasize other cells. It always wins but saws the branch on which it sits. Mankind also grows exponentially, killing thousands of other species, poisoning the oceans and soft waters, polluting the atmosphere, all for his egoistic needs. Man also travels and metastasizes other Earths. He modifies his genome or that of other species, and develops new technologies for his reproduction. He can destroy the planet in an eyeblink. To be or not to be the malignant primate, that will be the dilemma for the 21st Century.  相似文献   

18.
The principal psychoactive component of marijuana, Δ(9)-tetrahydrocannabinol (THC), activates CB1 cannabinoid receptors (CB1Rs). Unfortunately, pharmacological research into the design of effective THC analogs has been hampered by psychiatric side effects. THC-based drug design of a less academic nature, however, has led to the marketing of "synthetic marijuana," labeled as K2 or "Spice," among other terms, which elicits psychotropic actions via CB1R activation. Because of structural dissimilarity to THC, the active ingredients of K2/Spice preparations are widely unregulated. The K2/Spice "phenomenon" provides a context for considering whether marijuana-based drugs will truly provide innovative therapeutics or merely perpetuate drug abuse.  相似文献   

19.
Edward Llewellyn Thomas 《CMAJ》1966,94(15):808-811
The good physician of the future will need to master not only the basic and traditional medical skills but many new concepts and techniques as well. He will need to be, as always, a compassionate and intelligent man. If he is to retain his status as a healer in the eyes of his patients, he will have to be fully aware of what is happening in the social and technological environment, or he will run the risk of being relegated to the position of a high-grade technician.He will have new physical tools and new thinking tools to help him. To understand and use these, and also to understand the technical world of the future, he will need a sound knowledge of the physical sciences and some fluency in the language of modern mathematics.  相似文献   

20.
By his own admission, Robert R. Ruffolo, Head of Research and Development at Wyeth-Ayerst, is a bit of a nerd. Opting to spend seven nights per week with his textbooks at the expense of all else, he earned his pharmacy degree summa cum laude, and his PhD in pharmacology in just over three years. He speaks with unabashed enthusiasm for the pharmaceutical industry, for biomedicine, and particularly for the future of pharmacology. Even if you don't know Ruffolo, you've probably seen him-if not at a science symposium, then surely as the lead "actor" in televised promotions that ran throughout 1999 on behalf of the Pharmaceutical Research and Manufacturers of America (PhRMA; scenes reproduced here, with permission). "Actor" belongs in quotation marks, because if there is such a thing as type casting, then Ruffolo is certainly an example in the PhRMA ads: passionate about good drugs and the people who need them; proud of his profession and his contributions; dedicated to science as well as to his colleagues; and grateful for the opportunities he has had to contribute. The commercial's requisite happy ending, where three generations of a coronary-prone farm family ride off into the sunset, reflects Ruffolo's own success story in helping to bring carvedilol to market. In all of this, however, Ruffolo's sincerity transcends the hokey as well as the nerdy. His devotion to science includes a mission to help others, and he would argue that in this and most ways, he is not so different from his academic colleagues.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号