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Selected AbstractsMolecular mechanisms of early gut organogenesis: A primer on development of the digestive tractDEVELOPMENTAL DYNAMICS, Issue 2 2003Julie C. Kiefer Abstract Creating an organ poses unique challenges in embryogenesis, including establishing an organ primordium and coordinating development of different tissues in the organ. The digestive tract (gut) is a complex organ system, posing the interesting question of how the development of a series of organs is coordinated to establish an organ system with a common function. Although gut development has been the focus of much research, the molecular mechanisms that regulate these events are just beginning to be understood. This primer will first outline the basic anatomy of the digestive tract and then focus on molecular mechanisms that drive vertebrate gut organogenesis. Deciphering mechanisms underlying gut organogenesis also provides insights into understanding the development of other organs. Developmental Dynamics 228:287,291, 2003. © 2003 Wiley-Liss, Inc. [source] Wild mouse open field behavior is embedded within the multidimensional data space spanned by laboratory inbred strainsGENES, BRAIN AND BEHAVIOR, Issue 5 2006E. Fonio The vast majority of studies on mouse behavior are performed on laboratory mouse strains (Mus laboratorius), while studies of wild-mouse behavior are relatively rare. An interesting question is the relationship between the phenotypes of M. laboratorius and the phenotypes of their wild ancestors. It is commonly believed, often in the absence of hard evidence, that the behavior of wild mice exceeds by far, in terms of repertoire richness, magnitude of variables and variability of behavioral measures, the behavior of the classical inbred strains. Having phenotyped the open field behavior (OF) of eight of the commonly used laboratory inbred strains, two wild-derived strains and a group of first-generation-in-captivity local wild mice (Mus musculus domesticus), we show that contrary to common belief, wild-mouse OF behavior is moderate, both in terms of end-point values and in terms of their variability, being embedded within the multidimensional data space spanned by laboratory inbred strains. The implication could be that whereas natural selection favors moderate locomotor behavior in wild mice, the inbreeding process tends to generate in mice, in some of the features, extreme and more variable behavior. [source] Physiological response to stress in fledgling Lesser Kestrels Falco naumanni: the role of physical condition, sex and individual genetic diversityIBIS, Issue 3 2009JOAQUÍN ORTEGO Exposure to chronic stress early on during development has important deleterious consequences later in life, reducing important components of individual fitness such as survival and future reproduction. In this study, we evaluate the factors associated with physiological response to stress in fledgling Lesser Kestrels Falco naumanni, paying particular attention to the potential role of individual genetic diversity. For this purpose, we used heterophil/lymphocyte ratios (H/L ratio) as a haematological stress indicator and typed the analysed individuals at 11 highly polymorphic microsatellite loci, which allowed us to estimate their genetic diversity. We found that the H/L ratio decreases with fledgling physical condition, suggesting that this parameter is a good indicator of nutritionally based physiological stress. Physiological response to stress was higher in males than in females and this effect was independent of physical condition, suggesting that the observed pattern is due to inherent sexual differences in the factors influencing H/L ratios. Finally, the H/L ratio was positively associated with the genetic diversity of offspring. Previous experimental studies have found that individuals with higher genetic diversity show increased levels of circulating glucocorticoids, which in turn are directly responsible for increasing H/L ratios. On this basis, we suggest that a positive effect of genetic diversity on corticosterone levels may explain the observed association between H/L ratios and individual heterozygosity. Overall, this study highlights the utility of leucocyte profiles to study stress in wild bird populations and poses an interesting question about the effects of individual genetic diversity on haematological response to stress. [source] Comparison of testes structure, spermatogenesis, and spermatocytogenesis in young, aging, and hybrid cichlid fish (Cichlidae, Teleostei)JOURNAL OF MORPHOLOGY, Issue 3 2003Lev Fishelson Abstract Testis structure, spermatogenesis, and spermatocytogenesis were compared in 13 species of cichlid fishes, belonging to the subfamilies Haplochrominae and Tilapinae. The species studied were either mouth brooders, in which fertilization occurs mostly inside the mouth of the brooding fish, or substrate brooders, whose eggs adhere to a substrate over which the sperm is ejaculated. In this study, the embryogenesis of testes anlagen and sperm production was followed in embryos and in fish up to 15 years old, as well as in hybrids of the two subfamilies. In cichlids, the testes are of the unrestricted type and primary spermatogonia develop along the entire length of the developing sperm tubule. The first primary spermatogonia are observed in the testes anlagen 2,5 days after fertilization and they continue to develop in cysts formed by the enveloping Sertoli cells and the intertubular elements. The dimensions of such primary and secondary spermatocysts are correlated with the number of spermatogonia they contain and the corresponding number of mitotic multiplications. The largest mature cysts attained 300 ,m, and contained 2,200,2,400 spermatids in the mouth-brooding species and 2,600,3,200 in the substrate-brooding species. Despite the fact that in such cysts cytoplasmic bridges connect only the isogamete spermatids, the maturation of all cells and consequent spermiation is synchronized. Meristic characters distinguish the sperm of mouth brooders from those of substrate brooders, especially in the number of mitochondria and length of the flagellum. In older fish and hybrids, various changes can be seen in the gametogenic epithelium and intertubular cells. These include thickening of the connective tissue, formation of "yellow" groups of Leydig cells, cell apoptosis and degeneration, and, especially, formation of large spermatogonia, with large, electron-dense nucleoli, that have the cytological characteristics of oocytes. The intra- and interspecific variability of sperm dimensions in the studied cichlids poses an interesting question in the context of sperm competition. J. Morphol. 256:285,300, 2003. © 2003 Wiley-Liss, Inc. [source] Cannabinoid receptor ligands as potential anticancer agents , high hopes for new therapies?JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2009Susanne Oesch Abstract Objectives The endocannabinoid system is an endogenous lipid signalling network comprising arachidonic-acid-derived ligands, cannabinoid (CB) receptors, transporters and endocannabinoid degrading enzymes. The CB1 receptor is predominantly expressed in neurons but is also co-expressed with the CB2 receptor in peripheral tissues. In recent years, CB receptor ligands, including ,9 -tetrahydrocannabinol, have been proposed as potential anticancer agents. Key findings This review critically discusses the pharmacology of CB receptor activation as a novel therapeutic anticancer strategy in terms of ligand selectivity, tissue specificity and potency. Intriguingly, antitumour effects mediated by cannabinoids are not confined to inhibition of cancer cell proliferation; cannabinoids also reduce angiogenesis, cell migration and metastasis, inhibit carcinogenesis and attenuate inflammatory processes. In the last decade several new selective CB1 and CB2 receptor agents have been described, but most studies in the area of cancer research have used non-selective CB ligands. Moreover, many of these ligands exert prominent CB receptor-independent pharmacological effects, such as activation of the G-protein-coupled receptor GPR55, peroxisome proliferator-activated receptor gamma and the transient receptor potential vanilloid channels. Summary The role of the endocannabinoid system in tumourigenesis is still poorly understood and the molecular mechanisms of cannabinoid anticancer action need to be elucidated. The development of CB2 -selective anticancer agents could be advantageous in light of the unwanted central effects exerted by CB1 receptor ligands. Probably the most interesting question is whether cannabinoids could be useful in chemoprevention or in combination with established chemotherapeutic agents. [source] Using non,time,series to determine supply elasticity: how far do prices change the Hubbert curve?OPEC ENERGY REVIEW, Issue 2 2002Douglas B. Reynolds An important concern of OPEC's work is to be able to understand how much supply of oil exists in different countries, in order to help better conserve oil. This paper extends M. King Hubbert's oil production and discovery forecasting model (Hubbert, 1962), using a non,time,series cumulative discovery and production quadratic Hubbert curve and structural shift variables to model technology and regulation changes. The model can be used to determine better world oil supplies. Price is tested, to see how powerful it is for increasing or decreasing oil supply. Using a trend of cumulative production, instead of time, will help to better fix the supply elasticity with respect to price, which is shown to be very inelastic. An interesting question is whether cumulative discovery or production constitutes an I(2) variable. This paper explains that they are not I(2) variables. [source] Supernumerary Pregnancy, Collective Harm, and Two Forms of the Nonidentity ProblemTHE JOURNAL OF LAW, MEDICINE & ETHICS, Issue 4 2006M. A. Roberts An interesting question, in both the moral and the legal context, is whether babies born of an infertility treatment-induced supernumerary pregnancy (or ITISP) are properly considered to have been harmed. One might wonder how such a question could even arise in the face of data that clearly demonstrate that ITISP leaves an unduly large number of babies blind, deaf, and palsied, and facing lifelong disabilities. In fact, however, a number of arguments, based on the problem of collective form and two forms of the so-called "nonidentity problem," challenge the claim of harm in the ITISP context. The purpose of the present paper is to establish, as against these arguments, that harm has been imposed on the ITISP-damaged offspring. [source] Poetics of Memory: In Defence of Literary Experimentation with Holocaust Survivor TestimonyANTHROPOLOGY & HUMANISM, Issue 1 2010Frances Rapport SUMMARY This article defends literary experimentation through poetics, suggesting it is both valid and powerful for re-presenting social data. The article concentrates on methodological debates surrounding the use of poetics in social science studies, contextualizing the theoretical with exemplars taken from a study of Holocaust survivors' life stories that aimed to clarify whether notions of health and well-being were in evidence in survivor testimony. In so doing, the article raises an interesting question: "What happens when a poet and a qualitative health researcher work on the same sections of transcribed text?" The article argues for the value of poetics as a working method with oral histories of this kind, suggesting its major strength is to uphold processes of personal transformation via layers of differently mediated dialogue: between participant and researcher, researcher and reader, and the like. The article concludes with a discussion of how poetics might be useful to support others' research studies. [source] Transactions costs as an obstacle to fisheries self-governance in New ZealandAUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 3 2010Ralph E. Townsend When faced with opportunities for greater self-governance, the New Zealand fishing industry managed to make only limited progress. Why industry was unable to progress self-management more effectively remains an interesting question. This paper argues that the benefits of greater self-governance were probably less than the significant transactions costs to self-organise. The benefits were probably smaller in New Zealand than elsewhere, because reform had already reduced the costs of fisheries administration. And the transactions costs confronting industry were substantial. First, unanimous agreement was required for self-governance, which created high transactions costs. Second, the tools for private enforcement were limited. Third, policy failed to specify clearly the expectations of self-governance, so the investments in self-governance are unusually risky. The government had unrealistic expectations that self-governance would solve third-party environmental externalities as well as fishing externalities. This implied high transactions costs to negotiate with third parties, such as environmental groups. Fourth, the standards for accountability were difficult to specify. This experience identifies four key policies if devolved fisheries governance is to be promoted: non-unanimous decision-making; private enforcement; clarity on areas for self-governance; and clarity on accountability standards. [source] Dilute Doping, Defects, and Ferromagnetism in Metal Oxide SystemsADVANCED MATERIALS, Issue 29 2010Satishchandra B. Ogale Over the past decade intensive research efforts have been carried out by researchers around the globe on exploring the effects of dilute doping of magnetic impurities on the physical properties of functional non-magnetic metal oxides such as TiO2 and ZnO. This effort is aimed at inducing spin functionality (magnetism, spin polarization) and thereby novel magneto-transport and magneto-optic effects in such oxides. After an early excitement and in spite of some very promising results reported in the literature, this field of diluted magnetic semiconducting oxides (DMSO) has continued to be dogged by concerns regarding uniformity of dopant incorporation, the possibilities of secondary ferromagnetic phases, and contamination issues. The rather sensitive dependence of magnetism of the DMSO systems on growth methods and conditions has led to interesting questions regarding the specific role played by defects in the attendant phenomena. Indeed, it has also led to the rapid re-emergence of the field of defect ferromagnetism. Many theoretical studies have contributed to the analysis of diverse experimental observations in this field and in some cases to the predictions of new systems and scenarios. In this review an attempt is made to capture the scope and spirit of this effort highlighting the successes, concerns, and questions. [source] Optimal timing and dosing of platelet transfusionsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010N. M. Heddle Background, Over the past 20 years there have been more than 20 randomized controlled trials (RCTs) that have investigated various aspects of platelet transfusion therapy in haematology/oncology patients. These studies have focused on the best platelet product, the importance of ABO compatibility, pathogen inactivation of platelets, platelet triggers and the optimal platelet dose. Aims, This article summarizes current evidence to support the timing and dosing of platelet transfusions and to explore some ideas of where clinical research in this area may be heading. Materials and Methods, The articles reviewed in this presentation were identified through a search of PubMed using the term, platelet transfusion and setting limits to identify clinical studies, human studies and manuscripts in English. Results and Discussion, Three RCTs have informed practices around platelet transfusion trigger with the largest study by Rebulla et al., being the primary study that has changed practices worldwide, with a move towards a lower prophylactic platelet transfusion trigger of 10 × 109/l. Two groups (Germany and Oxford, UK) are currently investigating whether we can push the boundaries of prophylactic platelet transfusions even further by eliminating this form of therapy. Preliminary results from these studies have been published but we will await the final results to determine whether this research will indeed change practice. Over the past year there has also been two major studies (one by the BEST Collaborative, and the second by the US Transfusion Medicine/Hemostasis Network), that provide new information to guide platelet dosing. The Study by the BEST Collaborative (SToP) compared low dose platelets to standard dose platelets with WHO bleeding greater than or equal to Grade 2 as the primary outcome. The US study (PLADO) compared three doses (low, medium and high) and measured the same outcome (WHO bleeding , Grade 2). Conclusions, Although all of these studies further our knowledge to prescribe platelet transfusions, they also raise some interesting questions about the clinical relevance of the outcomes that we are currently using for these studies. The trend over the past decade has been to use bleeding as the primary outcome; however, bleeding is a complex composite outcome (Grades 2, 3 and 4) comprised of some surrogate components (Grades 2 and 3). It is also an outcome that may be difficult to measure and grade in a consistent and reliable manner. The clinical relevance of this outcome is also complex and may vary depending on the perspective from which it is viewed. [source] A geometric morphometric study of regional differences in the ontogeny of the modern human facial skeleton,JOURNAL OF ANATOMY, Issue 3 2002Una Strand Viðarsdóttir Abstract This study examines interpopulation variations in the facial skeleton of 10 modern human populations and places these in an ontogenetic perspective. It aims to establish the extent to which the distinctive features of adult representatives of these populations are present in the early post natal period and to what extent population differences in ontogenetic scaling and allometric trajectories contribute to distinct facial forms. The analyses utilize configurations of facial landmarks and are carried out using geometric morphometric methods. The results of this study show that modern human populations can be distinguished based on facial shape alone, irrespective of age or sex, indicating the early presence of differences. Additionally, some populations have statistically distinct facial ontogenetic trajectories that lead to the development of further differences later in ontogeny. We conclude that population-specific facial morphologies develop principally through distinctions in facial shape probably already present at birth and further accentuated and modified to variable degrees during growth. These findings raise interesting questions regarding the plasticity of facial growth patterns in modern humans. Further, they have important implications in relation to the study of growth in the face of fossil hominins and in relation to the possibility of developing effective discriminant functions for the identification of population affinities of immature facial skeletal material. Such tools would be of value in archaeological, forensic and anthropological applications. The findings of this study underline the need to examine more deeply, and in more detail, the ontogenetic basis of other causes of craniometric variation, such as sexual dimorphism and hominin species differentiation. [source] Rear gunners and troubled privates: Wordplay in a dick joke competition1JOURNAL OF SOCIOLINGUISTICS, Issue 1 2007Mike Lloyd A humorous competition called ,The Adventures of Naked Man' ran in a Wellington (New Zealand) newspaper from 1999 to 2000. The competition's protagonist is the sole naked person in a drawn setting where, because of some convenient object or body position, his penis is obscured from sight. Entrants to the competition submitted a caption to go with the drawn setting, the point being to make humour. Without explicit instruction, most entrants constructed some form of dick joke, the interesting questions being, just how, and with what variations? These questions are pursued by drawing on the full corpus of Naked Man settings and captions. Basic principles of conversation analysis, including some early work of Sacks on punning, are used to analyse the nature and popularity of the Naked Man competition. The article also offers some more speculative comments to do with gender and the organisation of language about sexuality. [source] Planting the Nation's ,Waste Lands': Walter Scott, Forestry and the Cultivation of Scotland's WildernessLITERATURE COMPASS (ELECTRONIC), Issue 3 2009Susan Oliver In October 1827 the Quarterly Review included a review of the second edition of Robert Monteath's The Planter's Guide and Profitable Planter. The review was published anonymously according to custom, but the author was Sir Walter Scott. A keen amateur plantsman who would later be involved in producing official reports on tree husbandry in Scotland, Scott's interest in ecology, forestry and the cultural value of landscape was of long standing. He had spent a small fortune on trees for his Abbotsford estate, and the cost had contributed to his insolvency in 1826. The present article looks at Scott's review as a work of Romantic ecocriticism concerned with the relationships between nationhood, economics and natural sustainability. Definitions of ,waste land' are considered, and the use of literary references to emphasize the need for sustainable planting is explored along with debates over imported Canadian species of pine. The cultural exchange of trees for people is shown to raise interesting questions, as is the advent of the railways that Scott ignores in his essay despite his interest in that new form of transport. [source] Polymorphic microsatellite loci for primitively eusocial wasp Ropalidia marginataMOLECULAR ECOLOGY RESOURCES, Issue 4 2009S. JOHNY Abstract We report here development and characterization of 48 novel microsatellite markers for Ropalidia marginata, a tropical, primitively eusocial polistine wasp from peninsular India. Thirty-two microsatellites showed polymorphism in a wild population of R. marginata (N = 38) collected from Bangalore, India. These markers will facilitate answering some interesting questions in ecology and evolutionary biology of this wasp, such as population structure, serial polygyny, intra-colony genetic relatedness and the pattern of queen succession. [source] Leaving on the lights: host-specific derepression of Mycobacterium tuberculosis gene expression by anti-sigma factor gene mutationsMOLECULAR MICROBIOLOGY, Issue 5 2006Robert N. Husson Summary Regulation of transcription by alternative sigma factors is a strategy widely used by bacteria to adapt to changes in environmental conditions. For several pathogenic bacteria, alternative sigma factor-regulated gene expression is critical for virulence. The activity of many alternative sigma factors is in turn controlled by regulatory proteins that transduce and integrate environmental signals. In this issue of Molecular Microbiology, Said-Salim et al. demonstrate high-level expression of genes encoding major protein antigens in the bovine subspecies of Mycobacterium tuberculosis, in contrast to low-level expression in the human subspecies. Having previously suggested that SigK regulates the expression of these genes, the authors found that the high-expressers have point mutations in Rv0444c, a gene adjacent to sigK, and provided evidence that this gene encodes an anti-sigma factor whose function is abrogated by these mutations. These findings not only demonstrate an adaptive mechanism of potential importance in tuberculosis immunity and pathogenesis, but also raise interesting questions regarding the origin of these mutations and their effects on anti-sigma factor function. [source] Arabidopsis pathology breathes new life into the necrotrophs-vs.-biotrophs classification of fungal pathogensMOLECULAR PLANT PATHOLOGY, Issue 4 2004RICHARD P. OLIVER SUMMARY Fungal plant pathologists have for many decades attempted to classify pathogens into groups called necrotrophs, biotrophs and, more recently, hemibiotrophs. Although these terms are well known and frequently used, disagreements about which pathogens fall into which classes, as well as the precise definition of these terms, has conspired to limit their usefulness. Dogmas concerning the properties of the classes have been progressively eroded. However, the genetic analysis of disease resistance, particularly in the model plant Arabidopsis thaliana, has provided a biologically meaningful division based on whether defence against fungal pathogens is controlled via the salicylate or jasmonate/ethylene pathways. This mode-of-defence division distinguishes necrotrophs and biotrophs but it limits the biotroph class to pathogens that possess haustoria. The small number and limited range of pathogens that infect Arabidopsis means that several interesting questions are still unanswered. Do hemibiotrophs represents a distinct class or a subclass of the necrotrophs? Does the division apply to other plant families and particularly to cereals? and does this classification help us understand the intricacies of either fungal pathogenicity or plant defence? [source] Perceived blur in amblyopiaOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2002A. J. Simmers Purpose:, It is well documented that visual acuity and contrast sensitivity in amblyopia are attenuated at high spatial frequencies: this would predict that amblyopes should perceive objects as blurred because they lack high spatial frequency information necessary to adequately represent sharp edges. In a series of experiments, we explored the representation of blur in amblyopia with blur discrimination and blur matching tasks. Methods:, Monocular blur discrimination thresholds were measured in a spatial 2-Alternative Force Choice procedure. The luminance profiles of the blurred edge were cumulative Gaussians with the standard deviation of the reference blurred edge being fixed at 1.88, 3.75, 7.5, 15, 30, or 60 min arc. Observers were required to discriminate which edge (right or left) appeared to be the less blurred. Observers also interocularly matched edges which were identical to those employed in the blur discrimination tasks, with the exception that they were viewed dichoptically at all times. Results:, Blur discriminination thresholds were elevated in both the amblyopic and fellow fixing eye but were within the normal range for interocular matching thresholds. Our results suggest that blur is veridically represented in the amblyopic visual system. Conclusions:, The surprising result here is that all amblyopes, even those with the most severe visual loss, veridically matched all blurred edges, including the sharpest ones. This implies that amblyopes are able to represent levels of blur that are defined by spatial structure beyond their resolution limit. These results also raise interesting questions about the mechanism by which blur is represented in the visual system. [source] Auctions on the Internet: What's Being Auctioned, and How?THE JOURNAL OF INDUSTRIAL ECONOMICS, Issue 3 2000David Lucking-Reiley This paper is an economist's guide to auctions on the Internet. It traces the development of online auctions since 1993, and presents data from a comprehensive study of 142 different Internet auction sites. The results describe the transaction volumes, the types of auction mechanisms used, the types of goods auctioned, and the business models employed at the various sites. These new electronic-commerce institutions raise interesting questions for the economic theory of auctions, such as predicting the types of goods to be sold at auction, examining the incentive effects of varying auctioneer fee structures, and identifying the optimal auction formats for online sellers. [source] COORDINATION OF MONETARY AND FISCAL POLICY IN A MONETARY UNION: POLICY ISSUES AND ANALYTICAL MODELSTHE MANCHESTER SCHOOL, Issue 2007Article first published online: 9 AUG 200, MATTHEW B. CANZONERI The European Monetary Union raises new and interesting questions about the coordination of monetary and fiscal policy. In this lecture, I discuss some of these questions and the answers that a new class of models,new neoclassical synthesis (NNS) models,is currently giving to them. I will argue that the new questions expose some weaknesses in current NNS modeling; in particular, the models do not seem to explain the positive correlation between national inflation and growth differentials that has been observed in the European data. I also review some recent work that has been done on policy coordination within a currency union. [source] Widespread organisation of C. elegans genes into operons: Fact or function?BIOESSAYS, Issue 11 2002Rachael Nimmo A recent report by Blumenthal et al.1 provides convincing evidence that at least 15% of Caenorhabditis elegans genes are co-transcribed within over a thousand operons. Polycistronic transcription of gene clusters is very rare in eukaryotes. The widespread occurrence of operons in C. elegans thus raises some interesting questions about the origin and function of these multigenic transcriptional units. BioEssays 24:983,987, 2002. © 2002 Wiley-Periodicals, Inc. [source] | ||||||||||||||||||||||