bluuebunny/crossref_metadata_2025 huggingface dataset:
Separable Routes to Human Memory Formation: Dissociating Task and Material Contributions in the Prefrontal Cortex
Authors: Wig Gagan S. , Miller Michael B. , Kingstone Alan , Kelley William M.
Published: February 2004

The present study used fMRI to investigate functional dissociations across frontal regions during incidental memory formation. Subjects were imaged while encoding materials with differential access to phonological codes (nonfamous faces and nameable famous faces) under task conditions that encouraged elaborate (deep) or superficial (shallow) encoding strategies. Results revealed a functional dissociation between dorsal posterior regions of the prefrontal cortex (BA 6/44) that were sensitive to material type (famous vs. nonfamous), irrespective of the encoding task, and ventral anterior regions of the prefrontal cortex (BA 45/47) that were uniquely sensitive to task demands (deep vs. shallow), regardless of material type. Further, subjects realized a memorial advantage to the extent that they recruited these dissociable frontal regions. These results demonstrate a posterior/anterior dichotomy in the frontal cortex that underlies separable code-based routes to human memory formation.
Functional Parcellation of Attentional Control Regions of the Brain
Authors: Woldorff Marty G. , Hazlett Chad J. , Fichtenholtz Harlan M. , Weissman Daniel H. , Dale Anders M. , Song Allen W.
Published: February 2004

Recently, a number of investigators have examined the neural loci of psychological processes enabling the control of visual spatial attention using cued-attention paradigms in combination with event-related functional magnetic resonance imaging. Findings from these studies have provided strong evidence for the involvement of a fronto-parietal network in attentional control. In the present study, we build upon this previous work to further investigate these attentional control systems. In particular, we employed additional controls for nonattentional sensory and interpretative aspects of cue processing to determine whether distinct regions in the fronto-parietal network are involved in different aspects of cue processing, such as cue-symbol interpretation and attentional orienting. In addition, we used shorter cue-target intervals that were closer to those used in the behavioral and event-related potential cueing literatures. Twenty participants performed a cued spatial attention task while brain activity was recorded with functional magnetic resonance imaging. We found functional specialization for different aspects of cue processing in the lateral and medial subregions of the frontal and parietal cortex. In particular, the medial subregions were more specific to the orienting of visual spatial attention, while the lateral subregions were associated with more general aspects of cue processing, such as cue-symbol interpretation. Additional cue-related effects included differential activations in midline frontal regions and pretarget enhancements in the thalamus and early visual cortical areas.
Neuronal Bases of Perceptual Learning Revealed by a Synaptic Balance Scheme
Authors: Hoshino Osamu
Published: February 2004

Our ability to perceive external sensory stimuli improves as we experience the same stimulus repeatedly. This perceptual enhancement, called perceptual learning, has been demonstrated for various sensory systems, such as vision, audition, and somatosensation. I investigated the contribution of lateral excitatory and inhibitory synaptic balance to perceptual learning. I constructed a simple associative neural network model in which sensory features were expressed by the activities of specific cell assemblies. Each neuron is sensitive to a specific sensory feature, and the neurons belonging to the same cell assembly are sensitive to the same feature. During perceptual learning processes, the network was presented repeatedly with a stimulus that was composed of a sensory feature and noise, and the lateral excitatory and inhibitory synaptic connection strengths between neurons were modified according to a pulse-timing-based Hebbian rule. Perceptual learning enhanced the cognitive performance of the network, increasing the signal-to-noise ratio of neuronal activity. I suggest here that the alteration of the synaptic balance may be essential for perceptual learning, especially when the brain tries to adopt the most suitable strategy—signal enhancement, noise reduction, or both—for a given perceptual task.
How the Shape of Pre- and Postsynaptic Signals Can Influence STDP: A Biophysical Model
Authors: Saudargiene Ausra , Porr Bernd , Wörgötter Florentin
Published: February 2004

Spike-timing-dependent plasticity (STDP) is described by long-term potentiation (LTP), when a presynaptic event precedes a postsynaptic event, and by long-term depression (LTD), when the temporal order is reversed. In this article, we present a biophysical model of STDP based on a differential Hebbian learning rule (ISO learning). This rule correlates presynaptically the NMDA channel conductance with the derivative of the membrane potential at the synapse as the postsynaptic signal. The model is able to reproduce the generic STDP weight change characteristic. We find that (1) The actual shape of the weight change curve strongly depends on the NMDA channel characteristics and on the shape of the membrane potential at the synapse. (2) The typical antisymmetrical STDP curve (LTD and LTP) can become similar to a standard Hebbian characteristic (LTP only) without having to change the learning rule. This occurs if the membrane depolarization has a shallow onset and is long lasting. (3) It is known that the membrane potential varies along the dendrite as a result of the active or passive backpropagation of somatic spikes or because of local dendritic processes. As a consequence, our model predicts that learning properties will be different at different locations on the dendritic tree. In conclusion, such site-specific synaptic plasticity would provide a neuron with powerful learning capabilities.
Exiled to Freedom A Memoir of Censorship in Iran
Authors: Karimi-Hakak Mahmood
Published: February 2004

Maybe you think the challenge in directing Shakespeare's A Midsummer Night's Dream is to surpass Peter Brook's groundbreaking production of the early 1970s. Think again. Karimi-Hakak's struggle against the venality and stupidity of the authorities in Tehran who blocked his 1999 production of Dream is what he himself dubs “a midwinter nightmare.”
Make Love
Authors: Finley Karen
Published: February 2004

Finley's newest performance piece begins in a lounge where spectators are gathered for an evening of soft music. “It was such a beautiful day for a tragedy,” intones Finley. Then: “Don't you wish for the time when the problem was who is sucking Clinton's dick!!” From there, in her inimitable way, Finley invokes post—9/11 America, fusing her personal with our collective political.
Resuscitating the Extinct: The Backbreeding of Historic Animals at U.S. Living History Museums
Authors: Magelssen Scott
Published: February 2004

The shift to “living interpretation” in the second half of the 20th century redirected the trajectory of museum work. Living bodies were said to give a more real experience of the past than could historic objects. But what about those pigs, cows, chickens, and sheep found at every major living history museum? Nowadays museums seek rare breeds or they breed contemporary animals to bring them closer to descriptions found in historic documents. What are the ethical and political implications of “backbreeding”? Will museums determine that some backbreeding is legitimate, while others are the stuff of mad-scientist films?
In Search of Presence: A Systematic Evaluation of Evolving VLEs
Authors: Selverian Melissa Markaridian , Hwang Ha Sung
Published: February 2004

In an attempt to understand better the unique characteristics of an increasing popular, prevalent form of sense-engaging and interactive multimedia learning experience often called the “virtual learning environment” (VLE), this study systematically evaluates and analyzes the findings of seventeen original research studies in terms of technologies, teaching strategies, presence, and learning.

This evaluation identifies potentially significant relationships among these variables in VLEs with both low-and high-level learning objectives, from memorization and repetition to analysis and synthesis. The findings suggest, first, that, when technologies and teaching strategies are presented through a one-way immersion of the senses, learners most often respond with experiences of spatial presence; when technologies and teaching strategies are socially interactive in format, learners most often respond with experiences of social presence. This evaluation, importantly, suggests that levels of spatial presence may correlate with the achievement of lower-level learning objectives, that levels of social presence may correlate with the achievement of higher-level learning objectives, and that levels of spatial and social presence together may correlate most strongly with the achievement of higher-level learning objectives. The evaluation, finally, identifies a need and establishes a course for the consideration of presence in future VLE design and research.
Presence as Experience: Film Informing Ways of Staying There
Authors: Marsh Tim
Published: February 2004

Experience and the activities that provide it are associated with the virtual places where they were encountered, and this may instill in our imagination an illusion of an environment other than where an interactive mediated environment 1 (a virtual environment, virtual reality, or computer game) resides (home, work, or on the move). Appropriate and/or stimulating experience may encourage users to continue, or become engaged in, pursing activities in a mediated environment. The termstaying there is used to describe this situation of engagement. Conversely, if experience from use does not match up or deliver on expectations or purpose, or it is dull, boring, or uninteresting, then it may not hold user's attention and can potentially shift attention from the mediated to the real world. This paper describes the background work towards the development of a framework of experience with the aim of informing analysis and design of interactive mediated environments (IMEs) to induce/evoke stimulating experience in users and to encourage them in “staying there.” Informed from film-making, three levels of experience are explored: voyeuristic (“joy of seeing the new and the wonderful”), visceral (thrill of spectacle and attractions), and vicarious (transfer of emotion through another person, being, or object). With varying degrees of emphasis, story is experienced by spectators through one or a combination of these three to provide meaning. Drawing a parallel between developments in film and IMEs, situations, circumstances, features, and elements of IME design are identified that can induce/evoke these experiences in users. As well as informing analysis and design of experience of IMEs, this may provide an alternative way to reason about engagement and presence.

1 The term interactive mediated environment is used to encapsu-late similarities in many current, new, and emerging media types (vir-tual reality, virtual environments, computer games, the Internet) com-prising three-dimensional computer generated/manipulated visual environment or space (graphics, video, photographic, and so on) and provide the potential for user activities within the environment. To enhance a line of reasoning, individual media/platforms are referred to by name.
Crisis and Opportunity: NATO's Transformation and the Multilateralization of Détente, 1966–1968
Authors: Wenger Andreas
Published: February 2004

This article discusses how the North Atlantic Treaty Organization (NATO) overcame the challenged posed by France in the mid to late 1960s. French President Charles de Gaulle's decision to withdraw France's remaining forces from NATO's integrated military commands, and his visit to Moscow shortly thereafter, exposed the alliance to unprecedented tension. Yet as NATO moved toward a crisis, opportunities arose to define a new vision for the alliance in a time of détente. Trilateral talks among the United States, Britain, and the Federal Republic of Germany forged a consensus on strategy, force levels, burden sharing, and nuclear consultation a consensus that was endorsed by the other member-states. The Harmel exercise in 1967 restored NATO's political purpose, expanding its political role as an instrument of peace. By 1968 NATO had evolved into a less hierarchical military alliance of fourteen and a more political and participatory alliance offifteen (including France). This successful transformation of NATO moved the process of détente from the bilateral superpower accommodation of 1963 to the multilateral European rapprochement of the 1970s.
Public Diplomacy during the Cold War: The Record and Its Implications
Authors: Critchlow James
Published: February 2004

Public diplomacy in its many forms proved a great asset for the United States during the Cold War. A new book by Yale Richmond, a retired U.S. official who for many years was involved with policy toward the Soviet Union, including U.S. Soviet exchanges, highlights the importance of the “cultural” dimension of the Cold War. Richmond focuses on the U.S. side of the U.S. Soviet exchanges, but he also provides interesting comments about Soviet policy, drawing on newly declassified materials from the former Soviet archives. The exchanges, information programs, and other activities undertaken by the U.S. Information Agency and the Department of State played a crucial role in spreading democratic ideas and values within the Soviet bloc. Candid and balanced broadcasts were far more effective than the heavy—handed propaganda that was used initially. The record of public diplomacy during the Cold War provides some important lessons for U.S. foreign policy makers in the post—Cold War world.
The Persistence of the Kyoto Protocol: Why Other Annex I Countries Move on Without the United States
Authors: Hovi Jon , Skodvin Tora , Andresen Steinar
Published: February 2004

The United States, the world's largest emitter of greenhouse gases, is not going to ratify the Kyoto Protocol in the foreseeable future. Yet, a number of countries have decided to stay on the Kyoto track. Four main explanations for this apparent puzzle are considered. The first is that remaining Annex I countries still expect the Kyoto Protocol to reduce global warming sufficiently to outweigh the economic costs of implementation. The second is that the parties, by implementing the treaty, hope to induce non-parties to follow suit at some later stage. A third hypothesis is that EU climate institutions have generated a momentum that has made a change of course difficult. Finally, Kyoto's persistence may be linked to the European Union's desire to stand forth as an international leader in the field of climate politics. We conclude that the first two explanations have little explanatory power, but find the latter two more promising.
Civic Science for Sustainability: Reframing the Role of Experts, Policy-Makers and Citizens in Environmental Governance
Authors: Bäckstrand Karin
Published: February 2004

The essay reviews the notion of “civic science” in global environmental governance and how it is articulated in international relations, science studies, democratic theory and sustainability science. Civic science is used interchangeably with participatory, citizen, stakeholder and democratic science, which are all catch words that signify various attempts to increase public participation in the production and use of scientific knowledge. Three rationales for civic science are identified: restoring public trust in science, re-orienting science towards coping with the complexity of environmental problems and installing democratic governance of science. A central proposition is that the promotion of civic science needs to be coupled with a theoretical understanding of its institutional, normative and epistemological challenges. The science-politics interface needs to be reframed to include the triangular interaction between scientific experts, policy-makers and citizens.
Globalization, Poverty and the Environment in West Africa: Too Poor to Pollute?
Authors: Kütting Gabriela
Published: February 2004

This article explores the linkages between the local and the global in the case of the increasing dependence on cotton in West African economies. It argues that West African states are too poor to engage in the wide spread extremely damaging environmental practices the former Soviet republics or Latin American states have followed and then suffered from. This article demonstrates that this poverty leads to relatively minor environmental damage on the one hand and, on the other hand, is caused to a large extent by external forces. Cotton is a key export crop and the region is vulnerable to price fluctuations on world markets and to domestic consequences of cotton farming such as environmental and social problems. This article explores the structural origins and environmental consequences of cotton farming in West Africa from a holistic perspective, thus outlining the position of cash-crop dependent states in the global political economy from a social and environmental perspective. Although West Africa's subordinate role in the globalization process also means that problems arising out of the privatization of nature are not as acute as elsewhere, the lack of opportunity for higher-level integration perpetuates and aggravates West Africa's position in the world, leaving little room for ecological, social and welfare improvement. It is an ideal illustration of the classic sustainable development dilemma: poverty means relatively low environmental damage but the way out of poverty can only be achieved with substantial environmental sacrifices, thus making sustainable development an oxymoron.
Nonstate Influence in the International Whaling Commission, 1970–1990
Authors: Skodvin Tora , Andresen Steinar
Published: February 2004

The role of nonstate actors in international environmental politics has been given increased scholarly attention during the last decade. While most analyses are focused on direct nonstate influence at the international level, one main objective of this article is to develop a multi-level approach that allows analysis of nonstate influence channeled via the domestic decision making level. The point of departure for the analysis is the International Whaling Commission (IWC) during the period from 1970 to 1990, with a particular focus on the competition for influence characterizing the relationship between the scientific community and the environmental and animal rights movement. The analysis shows that domestic channels of influence may be equally, or even more important than channels of influence linked to the international decision making level. In the case of the IWC, for instance, the environmental and animal rights movement succeeded in mobilizing domestic public support, particularly in the United States, and had a key ally in the US government, Congress and Administration. The domestic role of this nonstate actor was of key importance to its success in influencing the development of the international whaling regime. The analysis shows, therefore, that examining the role of the domestic channel is integral to understanding nonstate influence on international policy-making, and particularly how some nonstate actors acquire influence at the expense of others.
JESU ANNAHME DER KINDER IN MATTHÄUS 19:13-15
Authors: Ostmeyer Karl-Heinrich
Published: February 2004

Die matthäische Version der Perikope von Jesu Annahme der Kinder in Mt 19:13-15 ist streng chiastisch gegliedert. Jeder Aussage im ersten Teil (V. 13) korrespondiert ein Wort oder eine Handlung Jesu im zweiten (Vv. 14-15). Mit Hilfe der Textstruktur lässt sich u.a. erklären, warum der Evangelist seine Vorlage um die Erwartung ergänzt, Jesus möge für die Kinder beten, diese Erwartung aber scheinbar nicht einlöst. Die Kindersegnungsperikope erweist sich als konzentrierter Ausdruck matthäischer Theologie: Für Matthäus bilden die durch Jesus vermittelte Kindschaft, die πρoσευχη als Mittel der Kommunikation mit dem Vater und die Basileia eine Einheit.
THE AROMATIC FRAGRANCES OF PARADISE IN THE GREEK LIFE OF ADAM AND EVE AND THE CHRISTIAN ORIGIN OF THE COMPOSITION
Authors: Nir Rivka
Published: February 2004

According to the Greek life of Adam and Eve, before his expulsion from Paradise, Adam received permission to take four kinds of aromatic fragrances to use as earthly incense offerings. These four spices do not correspond with the ingredients of the biblical incense offering. The kinds of spices and the fact that they were taken from Paradise attests to the Christian nature of this tradition. The aromatic fragrances are the earthly remains of Paradise and a kind of substitute for the tree of life whose oil, which symbolized Christ, bestows eternal life and was promised to Adam only at the end of time—at the resurrection. The Christian nature of the fragrances in GLAE is also expressed in its role as a means for atonement and its theological meaning at Adam's funeral and death.
Subspeciality training in hematology and oncology, 2003: results of a survey of training program directors conducted by the American Society of Hematology
Authors: Todd Robert F. , Gitlin Scott D. , Burns Linda J. ,   the Committee on Training Programs
Published: February 2004

A survey of directors of adult and pediatric hematology/oncology subspecialty training programs in the United States and Canada was conducted to assess the environment in which recruitment and training is conducted in these medical disciplines. A total of 107 program directors responded to the survey, representing 66% of internal medicine and 47% of pediatric subspecialty programs in hematology or hematology/oncology. Specific areas covered in the web-based questionnaire included the type and demographics of the training program, profile of the training program director, characteristics of the applicant pool and existing trainee recruits, characteristics of the training program environment and curricula, research productivity of trainees, and the career pathways taken by recent training program graduates (including dominant areas of clinical interest). The results of this survey show considerable heterogeneity in the recruiting practices and the environment in which subspecialty training occurs, leading the authors to recommend improvements in or a heightened attention to issues, including recruitment of minority trainees, flexibility to recruit international medical school graduates, timing of trainee acceptance, maintaining the financial support of Medicare graduation medical education (GME), training of physician scientists, organization of the continuity clinic experience, visibility of nonmalignant hematology as a career path, and level of training program director support. (Blood. 2004;103:4383-4388)
A minimalist approach to null subjects and objects in second language acquisition
Authors: Park Hyeson
Published: February 2004

Studies of the second language acquisition of pronominal arguments have observed that:

(1) L1 speakers of null subject languages of the Spanish type drop more subjects in their second language (L2) English than first language (L1) speakers of null subject languages of the Korean type and

(2) speakers of Korean-type languages drop more objects than subjects in their L2 English.

An analysis of these two asymmetries is conducted within the Minimalist Program framework (MP), which hypothesizes that language acquisition involves the learning of formal features of a target language.I propose, based on Alexiadou and Anagnostopoulou (1998), that the licensing of null subjects is conditioned by the interpretability of agreement features. When a language has [+interpretable] agreement features, raising of the verb to T (X-movement) satisfies the EPP requirement: hence, a null subject is allowed. On the other hand, in a language with [-interpretable] agreement features, the subject is obligatory since merger of the subject in the specifier of TP (XP-merge) is required to check the EPP feature. Learning of the obligatory status of English subjects is easier for Korean learners than for Spanish speakers since syntactically both English and Korean have the same feature value [-interpretable] (although null subjects are allowed in Korean for pragmatic reasons). Spanish has the opposite syntactic feature value [+interpretable] and resetting of this is more difficult. Licensing of null objects is hypothesized to be related to the strength of theta-features. Languages with strong theta-features, such as English and Spanish, do not allow null objects, whereas languages with weak theta-features like Korean allow null objects. It takes time for Korean speakers to learn the different value of English theta-features, resulting in the extended null object period in L2 English of Korean L1 speakers.
Predicting perceptual success with segments: a test of Japanese speakers of Russian
Authors: Larson-Hall Jenifer
Published: February 2004

A perception experiment involving a novel language pairing, that of Japanese as a first language (L1) and Russian as a second language (L2), was conducted with 33 Japanese learners of Russian to determine whether two phonological models could successfully predict patterns of perceptual difficulty with eight Russian segments.The Featural Model of L2 Perception (based on Brown, 1997) predicts that learners will only be able to accurately perceive those segments that are composed of features which are used in the (underspecified) L1 featural pool. Flege’s (1995) Speech Learning Model predicts that ‘new’ phones will eventually be acquired, but ‘similar’ phones will remain problematic. The former more adequately explained the data than the latter, and was also shown to more successfully predict difficulties than phonetic or phonemic status of the segments. Thus, this experiment further clarifies what factors affect the segmental perception of an L2 and why learners from the same L1 background often have similar perceptual ‘accents’. The success of the Featural Model in explaining perceptual success indicates that adult language learners are restricted by universal constraints and processes of natural language systems.
Linguistic structure with processing in second language research: is a ‘unified theory’ possible?
Authors: Selinker Larry , Kim Dae-Eun , Bandi-Rao Shoba
Published: February 2004

We investigate a unique attempt at working out a unified theory of second language acquisition (SLA), Carroll’s ‘Autonomous Induction Theory’. This theory integrates SLA traditions that often ignore each other and adds a learning theory where novel information gets created to resolve learning problems. Cognitive universals, modularity theory, universal grammar, inductive learning, initiation of learning, working and long-term memory, top-down and bottom-up processing, input, errors, correction and feedback, language transfer, fossilization, restructuring of interlanguage are amongst the concepts reviewed. This project thus spans multiple domains but leaves many unresolved issues. However, since these issues appear in one framework, we have found that altogether, it provides excellent discussion material for advanced students. Finally, we suggest some ways in which the burden of the denseness of the material might be lightened.
Effect of Manufacturer Reputation, Retailer Reputation, and Product Warranty on Consumer Judgments of Product Quality: A Cue Diagnosticity Framework
Authors: Purohit Devavrat , Srivastava Joydeep
Published: February 2004

In this article, we examine how consumers assess product quality when confronted with multiple cues. Based on cue diagnosticity, a conceptual framework is developed that differentiates between cue types and suggests that the diagnosticity of some cue types depends on the valence of other cue types in the environment. The cue diagnosticity framework is then used to assess the effects of manufacturer reputation, retailer reputation, and product warranty on consumer perceptions of product quality. Consistent with the conceptual framework, we find in 2 studies that warranty is not used in judgments of product quality when a manufacturer with a poor reputation sells directly to consumers or sells through a retailer with a poor reputation. However, when the same manufacturer sells through a reputed retailer, then the warranty is used in making quality evaluations. The results not only support the conceptual framework, but also highlight the important role that the retailer plays in assessments of product quality. The implications of the findings are discussed along with directions for future research.
Systemic Complications of Acromegaly: Epidemiology, Pathogenesis, and Management
Authors: Colao Annamaria , Ferone Diego , Marzullo Paolo , Lombardi Gaetano
Published: February 2004

This review focuses on the systemic complications of acromegaly. Mortality in this disease is increased mostly because of cardiovascular and respiratory diseases, although currently neoplastic complications have been questioned as a relevant cause of increased risk of death. Biventricular hypertrophy, occurring independently of hypertension and metabolic complications, is the most frequent cardiac complication. Diastolic and systolic dysfunction develops along with disease duration; and other cardiac disorders, such as arrhythmias, valve disease, hypertension, atherosclerosis, and endothelial dysfunction, are also common in acromegaly. Control of acromegaly by surgery or pharmacotherapy, especially somatostatin analogs, improves cardiovascular morbidity. Respiratory disorders, sleep apnea, and ventilatory dysfunction are also important contributors in increasing mortality and are beneficially advantaged by controlling GH and IGF-I hypersecretion. An increased risk of colonic polyps, which more frequently recur in patients not controlled after treatment, has been reported by several independent investigations, although malignancies in other organs have also been described, but less convincingly than at the gastrointestinal level. Finally, the most important cause of morbidity and functional disability of the disease is arthropathy, which can be reversed at an initial stage, but not if the disease is left untreated for several years.
Coregulator Function: A Key to Understanding Tissue Specificity of Selective Receptor Modulators
Authors: Smith Carolyn L. , O’Malley Bert W.
Published: February 2004

Ligands for the nuclear receptor superfamily control many aspects of biology, including development, reproduction, and homeostasis, through regulation of the transcriptional activity of their cognate receptors. Selective receptor modulators (SRMs) are receptor ligands that exhibit agonistic or antagonistic biocharacter in a cell- and tissue context-dependent manner. The prototypical SRM is tamoxifen, which as a selective estrogen receptor modulator, can activate or inhibit estrogen receptor action. SRM-induced alterations in the conformation of the ligand-binding domains of nuclear receptors influence their abilities to interact with other proteins, such as coactivators and corepressors. It has been postulated, therefore, that the relative balance of coactivator and corepressor expression within a given target cell determines the relative agonist vs. antagonist activity of SRMs. However, recent evidence reveals that the cellular environment also plays a critical role in determining SRM biocharacter. Cellular signaling influences the activity and subcellular localization of coactivators and corepressors as well as nuclear receptors, and this contributes to gene-, cell-, and tissue-specific responses to SRM ligands. Increased understanding of the effect of cellular environment on nuclear receptors and their coregulators has the potential to open the field of SRM discovery and research to many members of the nuclear receptor superfamily.
The cost of foraging by a marine predator, the Weddell sealLeptonychotes weddellii: pricing by the stroke
Authors: Williams Terrie M. , Fuiman Lee A. , Horning Markus , Davis Randall W.
Published: February 2004

Foraging by mammals is a complex suite of behaviors that can entail high energetic costs associated with supporting basal metabolism, locomotion and the digestion of prey. To determine the contribution of these various costs in a free-ranging marine mammal, we measured the post-dive oxygen consumption of adult Weddell seals (N=9) performing foraging and non-foraging dives from an isolated ice hole in McMurdo Sound, Antarctica. Dives were classified according to behavior as monitored by an attached video-data logging system(recording activity, time, depth, velocity and stroking). We found that recovery oxygen consumption showed a biphasic relationship with dive duration that corresponded to the onset of plasma lactate accumulation at approximately 23 min. Locomotor costs for diving Weddell seals increased linearly with the number of strokes taken according to the relationship: locomotor cost =–3.78+0.04 × stroke number (r2=0.74, N=90 dives), where locomotor cost is in ml O2kg–1. Foraging dives in which seals ingested Pleuragramma antarcticum resulted in a 44.7% increase in recovery oxygen consumption compared to non-foraging dives, which we attributed to the digestion and warming of prey. The results show that the energy expended in digestion for a free-ranging marine mammal are additive to locomotor and basal costs. By accounting for each of these costs and monitoring stroking mechanics, it is possible to estimate the aerobic cost of diving in free-ranging seals where cryptic behavior and remote locations prevent direct energetic measurements.
The substrate specificity of hormone-sensitive lipase from adipose tissue of the Antarctic fish Trematomus newnesi
Authors: Hazel J. R. , Sidell B. D.
Published: February 2004

Antarctic fishes of the suborder Notothenioidei characteristically possess large stores of neutral lipids that have been shown to be important both in conferring buoyant lift and as a caloric resource for energy metabolism. Previous work has established that the aerobic energy metabolism of Antarctic fish is fueled predominantly by the catabolism of fatty acids, with the catabolic machinery displaying a preference for the oxidation of unsaturated fatty acids. The composition of the fatty acids released from adipose tissue of Antarctic fish during lipolysis, however, has not previously been demonstrated. Employing a substrate competition assay, we have characterized the substrate specificity of hormone-sensitive lipase (HSL) from adipose tissue of the Antarctic fish Trematomus newnesi. Rates of oleic acid release from radiolabeled triolein were quantified in the presence and absence of a nonradiolabeled cosubstrate. Polyunsaturated species of triacylglycerols(TAGs) containing 18:2 or 20:4 depressed rates of oleate release by 70–75% below control values. Most of the molecular species of TAG containing monoenoic fatty acids (i.e. those containing 14:1, 16:1 or 20:1)had no significant effect on rates of oleate release. By contrast, oleate release from triolein was actually stimulated (by 2–4-fold) by both saturated species of TAG (i.e. those containing 14:0, 16:0 and 18:0) and those possessing long-chain (22:1 and 24:1) monoenes (by 1.2–1.5-fold). Thus,the rank order of substrate preference for adipose tissue HSL was:polyunsaturates > monoenes > saturates. Degree of fatty acid unsaturation had a more marked effect on rates of hydrolysis than did fatty acid chain length. In addition, the enzyme displayed a preference for the hydrolysis of sn-1,2 rather than sn-1,3 diacylglycerols. These data indicate that the substrate specificity of adipose tissue HSL may be an important factor in determining which fatty acids are mobilized during stimulated lipolysis and which are made available for catabolism by other tissues of Antarctic fishes. Our data further suggest that TAGs containing some saturated fatty acids may be sufficiently poor substrates for catabolism by HSL to explain their disproportionate accumulation in adipose tissue. Such a mechanism could also contribute to the ontogenetic accumulation of fats that has been reported as an underlying basis for the positive correlation of buoyancy with increasing body mass in this group.
All rainbow trout (Oncorhynchus mykiss) are not created equal:intra-specific variation in cardiac hypoxia tolerance
Authors: Faust Heather A. , Gamperl A. Kurt , Rodnick Kenneth J.
Published: February 2004

All of our previous work, and that of other investigators, shows that the trout heart only partially recovers following brief exposure to severe hypoxia or anoxia (i.e. it is hypoxia-sensitive). However, in preliminary studies, we found evidence to suggest that rainbow trout reared at a farm in Oregon (USA)have a significant degree of inherent myocardial hypoxia tolerance. To evaluate whether hearts from these trout are indeed hypoxia-tolerant, and thus to determine whether intra-specific variation in rainbow trout myocardial hypoxia tolerance exists, we measured in situ cardiac function and monitored myoglobin and lactate dehydrogenase (LDH) release (both indices of myocardial damage) in hearts that were exposed to varying durations(10–30 min) of severe hypoxia (PO =5–10 mmHg). There was a strong positive relationship between the duration of severe hypoxia and the degree of post-hypoxic myocardial dysfunction. However, the resulting dysfunction was modest, with hearts exposed to 30 min of severe hypoxia recovering 77% of their initial maximum cardiac output. Furthermore,myoglobin was not detected in the perfusate, and ventricular LDH activity did not vary in response to the duration of severe hypoxia. These data (1)indicate that trout from this farm have extremely hypoxia-tolerant hearts; (2)suggest that considerable intra-specific variation exists in trout myocardial hypoxia tolerance; and (3) provide preliminary evidence that trout hearts are not irreversibly damaged, but are merely `stunned', following brief periods(10–30 min) of severe hypoxia.
Desiccation and rehydration elicit distinct heat shock protein transcript responses in flesh fly pupae
Authors: Hayward Scott A. L. , Rinehart Joseph P. , Denlinger David L.
Published: February 2004

Heat shock proteins (Hsps) are a ubiquitous component of the cellular response to stress in both prokaryotic and eukaryotic organisms, but their role and function during desiccation stress in terrestrial arthropods has received limited attention. Molecular responses to rehydration are arguably as important as those to desiccation in maintaining cellular integrity and enzyme activity, but the role of Hsps during stress recovery is poorly understood and has never been addressed with respect to rehydration in insects. This study identifies distinct differences in the Hsp response to desiccation and rehydration in the flesh fly Sarcophaga crassipalpis, as well as differences in the desiccation responses of diapausing and nondiapausing pupae. In nondiapausing pupae, the expression of two inducible Hsps (Hsp23 and Hsp70) is upregulated by desiccation, but the water loss threshold for Hsp expression changes at different rates of dehydration. Continued desiccation results in the prolonged expression of both Hsp23 and Hsp70, which may contribute to the delayed adult eclosion noted in samples desiccated for more than 3 days at <5% relative humidity/25°C. In diapausing pupae, hsp23 and hsp70 transcripts are already highly expressed and are not further upregulated by desiccation stress. Both of the constitutive Hsps investigated, Hsp90 and Hsc70, were unresponsive to desiccation in both nondiapausing and diapausing pupae. However, both Hsp90 and Hsc70 were upregulated upon rehydration in nondiapausing and diapausing pupae. These results indicate distinct roles for the different Hsps during desiccation stress and rehydration/stress recovery. The response to desiccation recovery(rehydration) is similar to the Hsp response to cold recovery identified in S. crassipalpis: Hsp90 and Hsc70 are upregulated in both cases.
Kinematics and hydrodynamics of swimming in the mayfly larva
Authors: Brackenbury John
Published: February 2004

The kinematics and hydrodynamics of free-swimming mayfly larvae(Chloeon dipterum) were investigated with the aid of a simple wake visualisation technique (tracer dyes) and drag measurements on dead insects. The basic swimming movement consists of a high-amplitude dorso-ventral undulation and, during continuous swimming, this produces a wake of ring vortices shed alternately to the dorsal and ventral sides of the body. The ring vortices propagate laterally away from the body at an angle of approximately 80° relative to dead aft of the swimming line. Thus, mayfly larvae, like damsel-fly larvae, resemble eels in producing a wake consisting of separate vortices that propagate laterally rather than the reverse von Karman vortex street characteristic of most caudal fin swimming fish. The thrust estimated from the momentum in the wake of swimming mayfly larvae was comparable with the drag measured on dead specimens. Possible sources of error in these estimates are discussed, but the conclusion is reached that even though only 14% of the total force generated by vortex production is directed forwards, it is still sufficient to account for the thrust required for steady locomotion.
Seawater acclimation causes independent alterations in Na+/K+- and H+-ATPase activity in isolated mitochondria-rich cell subtypes of the rainbow trout gill
Authors: Hawkings Guy S. , Galvez Fernando , Goss Greg G.
Published: February 2004

Mitochondria-rich cells (MR cells) of the gills of rainbow trout undergo changes in relative distribution and biochemical function during acclimation to partial-strength (10‰) and full-strength (30‰) seawater. In isolated total gill cells, Na+/K+-ATPase activity increased fivefold and H+-ATPase activity decreased fourfold when trout were acclimated to either 10‰ or 30‰ seawater. When total MR gill cells were separated based on differential binding to peanut lectin agglutinin (PNA), the PNA subtypes underwent a change in relative distribution in seawater-acclimated fish. In freshwater, the ratio of PNA–:PNA+ was 65:35 while in seawater the distribution changed to 20:80 PNA–:PNA+. Additionally, differential changes in Na+/K+-ATPase and H+-ATPase activity in each of the independent cell types occurred during seawater acclimation; Na+/K+-ATPase activity in the PNA– cells increased by 197% while in PNA+cells Na+/K+-ATPase decreased by 57%. However,H+-ATPase activity was decreased in both PNA–(84%) and PNA+ (72%) subtypes during acclimation to seawater.
The early ontogeny of neuronal nitric oxide synthase systems in the zebrafish
Authors: Holmqvist B. , Ellingsen B. , Forsell J. , Zhdanova I. , Alm P.
Published: February 2004

To examine a putative role for neuronal nitric oxide synthase (nNOS) in early vertebrate development we investigated nNOS mRNA expression and cGMP production during development of the zebrafish Danio rerio. The nNOS mRNA expression in the central nervous system (CNS) and periphery showed a distinct spatio–temporal pattern in developing zebrafish embryo and young larvae. nNOS mRNA expression was first detected at 19 h postfertilisation (h.p.f.), in a bilateral subpopulation of the embryonic ventrorostral cell cluster in the forebrain. The number of nNOS mRNA-expressing cells in the brain slowly increased, also appearing in the ventrocaudal cell cluster from about 26 h.p.f., and in the dorsorostral and hindbrain cell cluster and in the medulla at 30 h.p.f. A major increase in nNOS mRNA expression started at about 40 h.p.f., and by 55 h.p.f. the expression constituted cell populations in differentiated central nuclei and in association with the proliferation zones of the brain, and in the medulla and retina. In parts of the skin, nNOS mRNA expression started at 20 h.p.f. and ended at 55 h.p.f. Between 40 and 55 h.p.f., nNOS mRNA expression started in peripheral organs, forming distinct populations after hatching within or in the vicinity of the presumptive swim bladder, enteric ganglia, and along the alimentary tract and nephritic ducts. Expression of nNOS mRNA correlated with the neuronal differentiation pattern and with the timing and degree of cGMP production.

These studies indicate spatio–temporal actions by NO during embryogenesis in the formation of the central and peripheral nervous system,with possible involvement in processes such as neurogenesis, organogenesis and early physiology.
Allometry of kinematics and energetics in carpenter bees (Xylocopa varipuncta)hovering in variable-density gases
Authors: Roberts Stephen P. , Harrison Jon F. , Dudley Robert
Published: February 2004

We assessed the energetic and aerodynamic limits of hovering flight in the carpenter bee Xylocopa varipuncta. Using normoxic, variable-density mixtures of O2, N2 and He, we were able to elicit maximal hovering performance and aerodynamic failure in the majority of bees sampled. Bees were not isometric regarding thorax mass and wing area, both of which were disproportionately lower in heavier individuals. The minimal gas density necessary for hovering (MGD) increased with body mass and decreased with relative thoracic muscle mass. Only the four bees in our sample with the highest body mass-specific thorax masses were able to hover in pure heliox. Wingbeat frequency and stroke amplitude during maximal hovering were significantly greater than in normodense hovering, increased significantly with body mass during normodense hovering but were mass independent during maximal hovering. Reserve capacity for wingbeat frequency and stroke amplitude decreased significantly with increasing body mass, although reserve capacity in stroke amplitude (10–30%) exceeded that of wingbeat frequency(0–8%). Stroke plane angle during normodense hovering was significantly greater than during maximal hovering, whereas body angle was significantly greater during maximal hovering than during normodense hovering. Power production during normodense hovering was significantly less than during maximal hovering. Metabolic rates were significantly greater during maximal hovering than during normodense hovering and were inversely related to body mass during maximal and normodense hovering. Metabolic reserve capacity averaged 34% and was independent of body mass. Muscle efficiencies were slightly higher during normodense hovering. The allometry of power production,power reserve capacity and muscle efficiency were dependent on the assumed coefficient of drag (CD), with significant allometries most often at lower values of CD. Larger bees operate near the envelope of maximal performance even in normodense hovering due to smaller body mass-specific flight muscles and limited reserve capacities for kinematics and power production.
Migratory orientation of first-year white storks (Ciconia ciconia): inherited information and social interactions
Authors: Chernetsov Nikita , Berthold Peter , Querner Ulrich
Published: February 2004

We used satellite tracking to study the migratory orientation of juvenile white storks from the population in the Kaliningrad Region (Russia) during their first autumn migration. Two series of experiments were performed. In the first series of experiments, several groups of first-year storks were raised in an aviary, kept there until all free-living conspecifics had left the area and then released. These birds had to select their migratory route on the basis of the inherited directional information they possessed, without any chance of being guided by their experienced conspecifics. In the second series of experiments, several groups of juveniles were displaced from the Kaliningrad Region to the Volga area and to Western Siberia. Both areas lie outside the breeding range of the white stork so the displaced birds also had to rely on their innate migratory program. Results from the differently designed experiments did not match. Nor did they match with the results of earlier experiments on the delayed departure of juvenile white storks as reported by several authors. We suggest that naïve white storks (and maybe other soaring migrants) rely on social interactions when selecting their autumn migratory route to a much greater extent than do passerine long-distance migrants.