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1.
We have carried out a detailed analysis of the region of the hormone, which can be called an “active site”, that is essential for receptor binding and/or agonist activity, on the basis of structure-activity data of peptide hormones published in the literature. We find that one or more aromatic residues, often in a cluster, is present at the active sites of insulin, glucagon, adrenocorticotropin, gastrin, endorphins and angiotensin. Recognition of the functional importance of aromatic residues, combined with sequence comparisons and secondary structural predictions, enable us to identif active sites of nerve growth factor, somatostatin, calcitonin, parathyroid hormone and luteinizing hormone releasing hormone. Aromatic residues also appear to be essential for the function of nonpeptide hormones that act at the plasma membrane, and opiates. The apparently ubiquitous presence of aromatic groups at the active site of peptide hormones may facilitate understanding of the mechanism of action of hormones and provide insights into the design of hormone analogues.  相似文献   

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This contribution analyses the primacy of classification over generalization, and the philosophy of total evidence that emerges from the relation of homology to character statements. Primary conjectures of homology are basic character statements, i.e. statements that predicate properties of organisms, properties that are instantiated by those organisms and/or their parts. Secondary conjectures of homology are embedded in a second‐level (metalinguistic) discourse that turns on the coherence or incoherence of those basic character statements relative to a hierarchy. The coherence or incoherence of character statements is a logical relation between statements, not a causal (historical) relation between organisms. The choice of the hypothesis of relationships that is supported by the largest set of coherent basic character statements is based on the empirical presupposition that the properties referred to by the set of coherent character statements are grounded in causally efficacious relations of inheritance and ontogeny, and co‐instantiated because they are inherited through common ancestry (Hennig's auxiliary principle). Unless that empirical presupposition is causally grounded, phylogeny reconstruction is of an inherently probabilistic nature, whether under parsimony or other models of analysis. The causal grounding of a coherent set of character statements typically seeks a link between character statements and causally efficacious generative mechanisms for morphological characters (as is defeasibly indicated by topology and connectivity), or secondary structure information for molecular characters.  相似文献   

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The summer flounder, or fluke (Paralichthys dentatus)supports the most important commercial and recreational flatfishfisheries of the U.S. Atlantic coast. Thestock and fishery range from Massachusetts toNorth Carolina. Spawning takes place during aprotracted season that can extend fromSeptember to March, during an annual offshoreand southern migration to the outer continentalshelf off Virginia and North Carolina. Thefish are con-centrated in bays and estuariesfrom late spring through early autumn, when thenext offshore migration begins. The assessmentand management of the summer flounder fisheryhas been very contentious since theimplementation of the joint Atlantic StatesMarine Fisheries Commission/Mid-AtlanticFishery Management Council Fishery ManagementPlan (FMP) in 1989, when the poor status of thesummer flounder stock was evident toscientists, managers, and fishermen. Amendment2 to the FMP, approved in 1992, implementedseveral major regulatory provisions includingannual commercial quotas and recreationalharvest limits, and annually adjustable minimumlanded fish sizes, minimum mesh sizes,possession limits, and seasonal closures. By1999, fishing mortality on summer flounder haddeclined to its lowest level since the 1960s,and summer flounder total stock biomass was thehighest since the mid-1970s. Monitoring ofstock status is ongoing to reliably determine``how much fish is enough' to provide forlong-term sustainability. Many changes are madeannually to management measures due todiffering interpretations of stock status bymanagers, and fishery and environmentaladvocacy groups. Attainment of the annualfishing mortality targets remains elusive. Themultiple layers of science, management, andpolitics in place since 1992 continue to sparkmuch controversy and litigation that increasingly places the management of the summer flounder fishery in the hands of the courts.  相似文献   

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Recently theorists have developed competing accounts of the origins and nature of protolanguage and the subsequent evolution of language. Debate over these accounts is lively. Participants ask: Is music a direct precursor of language? Were the first languages gestural? Or is language continuous with primate vocalizations, such as the alarm calls of vervets? In this article I survey the leading hypotheses and lines of evidence, favouring a largely gestural conception of protolanguage. However, the “sticking point” of gestural accounts, to use Robbins Burling’s phrase, is the need to explain how language shifted to a largely vocal medium. So with a critical eye I consider Michael Corballis’s most recent expression of his ideas about this transition (2017’s The Truth About Language: What It Is And Where It Came From). Corballis’s view is an excellent foil to mine and I present it as such. Contrary to Corballis’s account, and developing Burling’s conjecture that musicality played some role, I argue that the foundations of an evolving musicality (i.e., evolving largely independently of language) provided the means and medium for the shift from gestural to vocal dominance in language. In other words, I suggest that an independently evolving musicality prepared ancient hominins, morphologically and cognitively, for intentional articulate vocal production, enabling the evolution of speech.  相似文献   

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This paper explores the language practices, attitudes to languages and the inter-generational transmission of heritage languages amongst the UK-born adult children of refugee parents. The paper draws on empirical data from a research project based on 45 qualitative interviews with three groups of “second generation” refugees, whose parents came as Tamil refugees from Sri Lanka, Kurdish refugees from Turkey and as refugees from Vietnam. The paper explores the ways in which language is central to political discussions and to national policies on race, cohesion, diversity, “Britishness” and citizenship. These debates and policies ignore and often silence the positive role of heritage languages. This paper highlights the importance of heritage languages as a signifier for a number of wider issues of identity, which intersect with race and refugee backgrounds in complex ways.  相似文献   

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Since the early 1990s, the term “genetic discrimination” has been used to designate adverse treatment on the grounds of genetic makeup. However, the full spectrum of possible disadvantage associated with genetic information has not been addressed by either the international scientific debate or statutory arrangements on genetic discrimination. Informed by legal contexts, they almost all focus on one specific group: the “asymptomatic ill.” On the basis of the sociological study, “Genetic Discrimination in Germany,” this article proposes to revise the terms of the debate and discusses some limitations of the concept. Drawing on the experiences reported by affected individuals, it advocates a more expansive social understanding which does not require that a person has to be healthy to be at risk of genetic discrimination.  相似文献   

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This article examines the complex interaction of nationalism, ethnicity and language during and after the 1940–45 Nazi occupation of Alsace. It focuses on the structure and texture of intergroup relations between Nazis and Alsatians, and analyses Alsatian claims that Nazi authorities did more for the cause of France and of the French language than two and a half centuries of previous French rule. It argues that in situations of intergroup contact, the role of cultural and linguistic similarity in predicting behaviour is secondary to the powerful effects of group self‐perception, perception of others, purposes, power, and identity/language choices. It shows that while historical and social contexts influence or determine language use, choice of language, in turn, offers significant clues about the perception of and reaction to particular circumstances. After World War II Alsatians felt the need to affirm their allegiance to France and to differentiate themselves from their former occupiers. These factors can be seen as an important cause of Alsatian acquiescence to French postwar assimilationist policies, and of the decline of the German dialect that has been spoken there for fifteen centuries.  相似文献   

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Finland’s Right to Return policy for Ingrian Finns (1990–2010) presented Russian and Estonian citizens who qualified as having Finnish ancestry the legal means to resettle in Finland. The policy was initially driven by Finnish President Mauno Koivisto, who spoke publicly of his belief that the Ingrian Finnish minority in Russia was Finnish because it was Lutheran rather than Orthodox. However, Finnish politicians increasingly abandoned the view of a common Lutheran identity between Ingrian Finns and Finland, and shifted the discussion to language, ancestry and historical memory, which were used to both endorse and disendorse Ingrian Finns’ Finnishness. We argue that the disappearance of religion from the Right to Return discourse was a strategic – if not necessarily conscious – choice that emphasized the more primordial aspects of Finnish identity (and the Ingrian Finns’ lack of those), which in turn enabled stricter restrictions and, ultimately, the discontinuation of the policy.  相似文献   

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This essay explores the proclamation of a “liberated space” as deployed by artists and activists of the NUDEC, Nuevo Nuevo Circo (New New Circus) in Caracas. Operating from a former bullring, these artists collectively interpret and define their terms for liberation, in part through an anti-bullfighting campaign centered on humanism as a political assertion in a venue for the arts. By examining the work of NUDEC in relation to the politics of public space during the first decade of the twenty-first century, certain parallels can be drawn between the New New Circus and the nation.  相似文献   

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《Autophagy》2013,9(3):228-230
Bafilomycin A1 (BafA1), which is a member of the plecomacrolide sub-class of macrolide antibiotics, has differential, concentration-dependent effects on neuronal cell viability. When used at high concentrations, BafA1 inhibits vacuolar ATPase (V-ATPase), promotes the accumulation of autophagic vacuoles and triggers Bax-dependent apoptosis. These effects are similar to those induced by the lysosomotropic agent chloroquine. Conversely, at concentrations below its reported ability to completely inhibit V-ATPase, BafA1 dramatically attenuates chloroquine-induced apoptosis. The protective effects of BafA1 appear to be independent of the chloroquine-induced accumulation of autophagosomes. Rather, BafA1 appears to inhibit events downstream of chloroquine-induced autophagosome accumulation, such as the loss mitochondrial or lysosomal integrity. Our finding that BafA1 inhibits the death of neurons induced by autophagic stress suggests a potentially novel mechanism of action apart from its ability to inhibit V-ATPase. Here we provide further evidence of neuroprotection against chloroquine-induced death by plecomacrolide antibiotics that are structurally similar to BafA1, including bafilomycin B1 and concanamycin A, and discuss potential mechanism(s) of neuroprotection against autophagic stress.

Addendum to:

Bafilomycin A1 Inhibits Chloroquine-Induced Death of Cerebellar Granule Neurons

John J. Shacka, Barbara J. Klocke, Masahiro Shibata, Yasuo Uchiyama, Geeta Datta, Robert E. Schmidt and Kevin A. Roth

Mol Pharmacol 2006; 69:1125-36  相似文献   

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Mass‐level and organizational politics contribute both to ethnic cohesion and division among American Jews. Political cohesion at the mass level, measured by location on the liberal side of the mass political structure, serves as a structural source of ethnic cohesion for many American Jews who are not characterized by alternative structural and cultural sources of ethnic cohesion, as measured by embeddedness in structural and cultural networks of interaction. However, political divisions among American jews converge with religious divisions and with variations in structural and cultural cohesion and assimilation; consequently, politics provides one of several reinforcing cleavages in the American Jewish community. Individual‐level data from the 1990 National Jewish Population Survey are used to support these claims. A strong linkage exists between patterns of ethnic cohesion and division and the role of politics at the mass and organizational levels. Jewish organizations involved in politics share consensus across a wide range of political issues, contributing to political cohesion. However, political conflicts emerge among organizations representing different Jewish denominations, leading again to reinforcing religious and political divisions. These claims are supported by data collected from the published reports of an umbrella agency which seeks to coordinate political positions among American Jewish organizations  相似文献   

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Abstract

The current A-level biology curriculum includes a broad coverage of all the biosciences which demands knowledge of a wide range of biological vocabulary. Students (n = 184) from two UK universities were presented with a list of vocabulary, associated with a ‘Revise Biology’ text which highlighted key terms that students should know. Lecturers (n = 26) were asked which of these terms they expected students to know, or be aware of. Findings revealed that students’ claimed knowledge of vocabulary exceeded lecturer expectations. In addition, there were a number of terms which students did not understand and lecturers did not expect them to know, which could be removed from A-level biology courses. This is discussed in relation to whether A-level curricula need to be so content heavy and whether lecturers would benefit from knowing more about their students’ knowledge of discipline-specific terms.  相似文献   

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Language is a uniquely human trait, and questions of how and why it evolved have been intriguing scientists for years. Nonhuman primates (primates) are our closest living relatives, and their behavior can be used to estimate the capacities of our extinct ancestors. As humans and many primate species rely on vocalizations as their primary mode of communication, the vocal behavior of primates has been an obvious target for studies investigating the evolutionary roots of human speech and language. By studying the similarities and differences between human and primate vocalizations, comparative research has the potential to clarify the evolutionary processes that shaped human speech and language. This review examines some of the seminal and recent studies that contribute to our knowledge regarding the link between primate calls and human language and speech. We focus on three main aspects of primate vocal behavior: functional reference, call combinations, and vocal learning. Studies in these areas indicate that despite important differences, primate vocal communication exhibits some key features characterizing human language. They also indicate, however, that some critical aspects of speech, such as vocal plasticity, are not shared with our primate cousins. We conclude that comparative research on primate vocal behavior is a very promising tool for deepening our understanding of the evolution of human speech and language, but much is still to be done as many aspects of monkey and ape vocalizations remain largely unexplored.  相似文献   

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On December 17, 2003, French President Jaques Chirac went on television to explain the immediate necessity of passing a law recently proposed by the Stasi commission. This commission had been empowered to explore the failures of the last thirty years of French immigration policy in terms of integration. It had also been specifically instructed to investigate threats to the concept of laicite, the rigorous French version of secularism and the separation of the Church and the State. Chirac explained that, following the commission’s advice as well as that of numerous experts, he had centered on a policy to deal with these issues: We shall do so by bringing to life the principle of secularism, which is a pillar of our constitution. It expresses our wish to live together in respect, dialogue and tolerance. Secularism guarantees freedom of conscience. It protects the freedom to believe or not to believe. He then expanded upon what this freedom requires: It is the neutrality of the public sphere which enables the harmonious existence side by side of different religions. Like all freedoms, the freedom to express one’s faith can only have limits in the freedom of others, and in the compliance with rules of life in society. Religious freedom, which our country respects and protects, must not be abused, it must not call general rules into question, and it must not infringe the freedom of belief of others. Finally, Chirac, building to a rhetorical climax, came to the essence of the new law which had provoked so much commentary around the world: In all conscience, it is my view that the wearing of clothes or of symbols which conspicuously demonstrate religious affiliations must be banned in state schools. The hypothesis which I wish to advance is that in the actual world in which we inhabit the language of morality is in the same state of grave disorder as the language of natural science is in the imaginary world which I described. What we possess are the fragments of a conceptual scheme... we posses indeed simulacra of morality... but we have lost our comprehension, both theoretical and practical, of morality.  相似文献   

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