New Information (new + information)

Distribution by Scientific Domains

Kinds of New Information

  • important new information

  • Selected Abstracts


    S. D. Killops
    A study of the molecular composition of oil inclusions in the Maui field, Taranaki Basin, New Zealand, reveals compositional variation in oil during the filling history of the Paleocene reservoir. The homogenization temperatures of aqueous inclusions in quartz suggest that oil in genetically associated inclusions first reached the proto-Maui structure about 7.0,7.5 Ma ago, and that an effective trap was present at the Paleocene F-sands level, given the abundant oil inclusions. This date coincides with what is believed to represent the early stages of structural development of the trap. The Maui or Pihama sub-basin appears the most likely kitchen for this early charge. The quartz-included oil exhibits a biomarker distribution with a slightly more marine-influenced signature than an oil stain from the same core plug, oil included in authigenic feldspar, and oil-production samples from the overlying Eocene D sands as well as the F sands. The greater similarity of the feldspar-included oil to the production oils together with its possibly slightly lower maturity suggest that the feldspar inclusions formed later than the quartz inclusions. Otherwise, all oil samples examined (inclusion oil, oil / bitumen in sandstones and producible oil) are of similar maturity. [source]

    How Much New Information Is There in Earnings?

    ABSTRACT We quantify the relative importance of earnings announcements in providing new information to the share market, using the R2 in a regression of securities' calendar-year returns on their four quarterly earnings-announcement "window" returns. The R2, which averages approximately 5% to 9%, measures the proportion of total information incorporated in share prices annually that is associated with earnings announcements. We conclude that the average quarterly announcement is associated with approximately 1% to 2% of total annual information, thus providing a modest but not overwhelming amount of incremental information to the market. The results are consistent with the view that the primary economic role of reported earnings is not to provide timely new information to the share market. By inference, that role lies elsewhere, for example, in settling debt and compensation contracts and in disciplining prior information, including more timely managerial disclosures of information originating in the firm's accounting system. The relative informativeness of earnings announcements is a concave function of size. Increased information during earnings-announcement windows in recent years is due only in part to increased concurrent releases of management forecasts. There is no evidence of abnormal information arrival in the weeks surrounding earnings announcements. Substantial information is released in management forecasts and in analyst forecast revisions prior (but not subsequent) to earnings announcements. [source]

    Redescription of Lagenophrys cochinensis Santhakumari & Gopalan, 1980 (Ciliophora, Peritrichia, Lagenophryidae), an Ectosymbiont of Marine Isopods, Including New Information on Morphology, Geographic Distribution, and Intraspecific Variation

    ABSTRACT. Lagenophrys cochinensis is a peritrich ciliate originally reported as an ectocommensal of the wood-boring isopods Sphaeroma terebrans, Sphaeroma triste, and Sphaeroma annandalei and the tanaidacean Apseudes chilkensis in estuaries of southern India. In the present study, it was found to occur also on Sphaeroma quoyanum, Sphaeroma walkeri, and Exosphaeroma planulum. New material was used to make permanent preparations, allowing a comprehensive description of the morphology of L. cochinensis for the first time. The macronucleus of L. cochinensis was found to have an elongate shape that spans the width of the cell body, unlike the compact macronucleus originally described. In addition, the loricae of all samples examined were subcircular or shorter than wide, not longer than wide as originally described. Polykinetid 3 of the infundibular infraciliature consisted of three rows of kinetosomes, only the third species of Lagenophrys found to have more than two rows in polykinetid 3 so far. Samples of L. cochinensis on S. quoyanum from New Zealand and California appeared to represent a population distinct from others. The species has a cosmopolitan distribution, probably owing to the ease with which its hosts are transported from one estuary to another in drifting wood or on hulls of ships. [source]

    Value of Transesophageal 3D Echocardiography as an Adjunct to Conventional 2D Imaging in Preoperative Evaluation of Cardiac Masses

    ECHOCARDIOGRAPHY, Issue 6 2008
    Silvana Müller M.D.
    Background: This study sought to compare three-dimensional (3D) and two-dimensional (2D) transesophageal echocardiography (TEE) to assess intracardiac masses. It was hypothesized that 3D TEE would reveal incremental information for surgical and nonsurgical management. Methods: In 41 patients presenting with intracardiac masses (17 thrombi, 15 myxomas, 2 lymphomas, 2 caseous calcifications of the mitral valve and one each of hypernephroma, hepatocellular carcinoma, rhabdomyosarcoma, lipoma, and fibroelastoma), 2D and 3D TEE were performed, aiming to assess the surface characteristics of the lesions, their relationship to surrounding structures, and attachments. Diagnoses were made by histopathology (n = 28), by computed tomography (n = 8), or by magnetic resonance imaging (n = 5). Benefit was categorized as follows: (A) New information obtained through 3D TEE; (B) helpful unique views but no additional findings compared to 2D TEE; (C) results equivalent to 2D TEE; (D) 3D TEE missed 2D findings. Results: In 15 subjects (37%), 3D TEE revealed one or more items of additional information (category A) regarding type and site of attachment (n = 9, 22%), surface features (n = 6, 15%), and spatial relationship to surrounding structures (n = 8, 20%). In at least 18% of all intracardiac masses, 3D TEE can be expected to deliver supplementary information. In six patients, additional findings led to decisions deviating from those made on the basis of 2D TEE. In 11 subjects (27%), 3D echocardiographic findings were categorized as "B." Conclusions: Information revealed by 3D imaging facilitates therapeutic decision making and especially the choice of an optimal surgical access prior to removal of intracardiac masses. [source]

    Primary hyperparathyroidism: new concepts in clinical, densitometric and biochemical features

    Abstract. Primary hyperparathyroidism (PHPT) is characterized most commonly now as an asymptomatic disorder with hypercalcaemia and elevated levels of parathyroid hormone (PTH). The elevation in PTH is detected by both the standard immunoradiometric assays (IRMA) and a more recent IRMA that detects only the 1,84 full-length PTH molecule. The serum calcium concentration is usually <1 mg dL,1 above normal. Recently, another variant of PHPT (normocalcaemic PHPT) has been described in which the serum calcium is normal but the serum PTH is elevated, in the absence of any secondary cause for PTH elevation. Although usually sporadic, PHPT also occurs in inherited syndromes. Skeletal manifestations are appreciated by densitometry showing a typical pattern in which cancellous bone of the lumbar spine is reasonably well preserved whilst the cortical bone of the distal third of the radius is preferentially reduced. Although reduced in incidence, renal stones remain the most common overt complication of PHPT. Other organs are theoretical targets of PHPT such as the neurobehavioural axis and the cardiovascular system. Vitamin D looms as an important determinant of the activity of the PHPT state. The 2002 NIH Workshop on asymptomatic PHPT has led to revised guidelines to help doctors determine who is best advised to have parathyroid surgery and who can be safely followed without surgery. New information about the natural history of PHPT in those who did not undergo surgery has helped to define more precisely who is at-risk for complications. At the NIH workshop, a number of items were highlighted for further investigation such as pharmacological approaches to controlling hypercalcaemia, elevated PTH levels and maintaining bone density. [source]

    Coma and respiratory failure due to moxidectin intoxication in a dog

    Alexander E. Gallagher DVM
    Abstract Objective: To describe the clinical consequences following ingestion by a dog of a moxidectin-containing equine deworming product. Few reports exist concerning the treatment and outcome of severe moxidectin toxicity. Treatment, known factors influencing intoxication, and prognosis are reviewed. Case summary: A 10-month-old female Border Collie ingested an unknown quantity of a moxidectin-containing equine deworming product several hours before presentation. Severe neurological signs subsequently developed and included: ataxia, seizures, coma, and respiratory failure. The dog was treated with supportive care including intravenous fluids, activated charcoal, and positive pressure ventilation. Normal spontaneous respiration returned in 34 hours and the patient was discharged 58 hours after ingestion. Full recovery occurred within 1 week of intoxication. New information provided: This report describes moxidectin intoxication and associated respiratory failure in a dog that required mechanical ventilation. The dog's recovery was rapid. Despite severity of signs, the prognosis for patients with moxidectin intoxication is good with appropriate supportive care. [source]

    A case of fatal anaphylaxis in a dog associated with a dexamethasone suppression test

    DACVECC, DACVIM, Michael Schaer DVM
    Abstract Objective: To describe a case of fatal anaphylaxis in a dog associated with a ,routine' dexamethasone suppression test. Case summary: An 8-year-old, spayed female dog, was treated with parenteral dexamethasone for a diagnosis of immune-mediated thrombocytopenia. The dog had responded to treatment, but 9 months later was evaluated for endogenous hyperadrenocorticism, prior to surgery for a ruptured anterior cruciate ligament. A normal ACTH stimulation test was followed by a high-dose dexamethasone suppression test. Immediately following the intravenous injection of dexamethasone, the dog developed severe anaphylactic shock and died. The postmortem examination findings supported the diagnosis of anaphylaxis. New information provided: The anaphylaxis in this dog was fulminating and by-passed the usual early signs of drug hypersensitivity. This is the first case in the veterinary literature reporting on dexamethasone as the cause of this dog's catastrophic event. [source]

    Essential medical facts for mental health practitioners

    Milton L. Wainberg M.D.
    New information about the life cycle of HIV, new HIV-specific laboratory tests, and newer antiretroviral medications have transformed the management of HIV illness. Knowledge about these changes will help mental health providers better understand the latest medical issues affecting their HIV-infected patients, which will assist them in providing better care. [source]

    Nutritional status, body composition, and intestinal parasitism among the Mbyá-Guaraní communities of Misiones, Argentina

    M.L. Zonta
    Indigenous communities in Argentina represent socially and economically neglected populations. They are living in extreme poverty and environmental degradation conditions. New information about health status and socio-environmental features is urgently needed to be applied in future sanitary policies. Present study describes the nutritional status, body composition, and intestinal parasitism among Mbyá-Guaraní children from three communities in the Misiones Province. Anthropometric parameters were analized for 178 individuals (aged 1,14). Data were transformed to z -scores using NHANES I and II. Stunting showed the greatest prevalence (44.9%). Children were found to have low arm circumference and low arm muscle area, although with tricipital skinfold value near to the reference. They also tend to have shorter than normal lower limbs. Fecal samples and anal brushes (for Enterobius vermicularis) were collected in 45 children (aged 1,13). Ritchie's sedimentation and Willis' flotation techniques were used to determine parasitoses. Ninety five percent of children were infected with at least one species and 81.4% were polyparasitized. The higher prevalences corresponded to Blastocystis hominis, hookworms (Ancylostoma duodenale/Necator americanus), and Entamoeba coli. Associations occurred between hookworms with B. hominis/E. coli and B. hominis with nonpathogenic amoebas. Thirty nine percent of the children with stunting presented B. hominis, Strongyloides, and hookworms. Our results indicate that this indigenous population is subjected to extreme poverty conditions and is one of the most marginalized in this country. Severe growth stunting and parasitic infection are still quite common among Mbyá children affecting about half of them along with significant changes in body composition and proportions. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source]

    Photoluminescence studies of isotopically enriched silicon

    D. Karaiskaj
    Abstract We report the first high resolution photoluminescence studies of isotopically pure silicon. New information is obtained on isotopic effects on the indirect band gap energy, phonon energies, and phonon broadenings, which is in good agreement with previous results obtained in germanium and diamond. Remarkably, the line widths of the no-phonon boron and phosphorus bound exciton transitions in the 28Si sample (99.896% 28Si) are much sharper than in natural Si, revealing new fine structure in the boron bound exciton luminescence. Most surprisingly, the small splittings of the neutral acceptor ground state in natural Si are absent in the photoluminescence spectra of acceptor bound excitons in isotopically purified 28Si, demonstrating conclusively that they result from the randomness of the Si isotopic composition. [source]

    The Phylogenetic Significance of Anthropoid Paranasal Sinuses

    James B. Rossie
    Abstract In this study, the phylogenetic significance of anthropoid paranasal sinus anatomy is explored. New information reported in recent years has precipitated new hypotheses of sinus homology and more than doubled the number of anthropoid genera for which confident assessments of sinus identity can be made. As a result, it is likely that the phylogenetic meaning of commonly cited characters such as the ethmoid and frontal sinuses will change. The traditional method of "character mapping" is employed to test hypotheses of sinus homology and to reconstruct the ancestral states for sinus characters in major anthropoid clades. Results show that most sinuses appear to be primitive retentions in anthropoids, with their absences in various genera representing losses. Accordingly, many of these sinuses are potential anthropoid synapomorphies. Anat Rec, 291:1485,1498, 2008. © 2008 Wiley-Liss, Inc. [source]

    New information from modern charge density methods

    Finn Krebs Larsen
    First page of article [source]

    Case for postoperative surveillance following colorectal cancer resection

    ANZ JOURNAL OF SURGERY, Issue 1-2 2004
    Tim R. Worthington
    Over 4 years have elapsed since the first National Health and Medical Research Council (NHMRC) guidelines were published for the management of patients after potentially curative resection of colorectal cancer. New information has now been published indicating that more intensive follow up than was originally recommended might provide a survival benefit for patients. This new information should be considered when formulating new NHMRC guidelines. In particular, meta-analyses of published individual trials have suggested a survival advantage that was not evident in the individual studies. There have been significant developments in chemotherapy with new individual agents and use of agents in combination that have proved far more effective than previous protocols. The therapeutic effect of these developments is the downstaging of some patients with metastatic disease, which was previously unresectable, to undergo resection. Furthermore, there is now some evidence that palliation of patients with advanced disease is more effective if commenced before the development of symptoms and this needs to be considered in the assessment of the benefits of follow up. There have been limited studies of cost-effectiveness, but international analyses suggest that the costs associated with more intensive follow-up regimes are within the accepted cost parameters associated with the management of many other conditions. [source]

    A critical analysis of the role of gut Oxalobacter formigenes in oxalate stone disease

    BJU INTERNATIONAL, Issue 1 2009
    Siddharth Siva
    Hyperoxaluria is a major risk factor for the formation of calcium oxalate stones, but dietary restriction of oxalate intake might not be a reliable approach to prevent recurrence of stones. Hence, other approaches to reduce urinary oxalate to manage stone disease have been explored. The gut-dwelling obligate anaerobe Oxalobacter formigenes (OF) has attracted attention for its oxalate-degrading property. In this review we critically evaluate published studies and identify major gaps in knowledge. Recurrent stone-formers are significantly less likely to be colonized with OF than controls, but this appears to be due to antibiotic use. Studies in animals and human subjects show that colonization of the gut with OF can decrease urinary oxalate levels. However, it remains to be determined whether colonization with OF can affect stone disease. Reliable methods are needed to detect and quantify colonization status and to achieve durable colonization. New information about oxalate transport mechanisms raises hope for pharmacological manipulation to decrease urinary oxalate levels. In addition, probiotic use of lactic acid bacteria that metabolize oxalate might provide a valid alternative to OF. [source]

    3164: Post-concussive syndrome

    Purpose Over 85% of traumatic brain injuries (TBI) are considered "mild", also referred to as "concussion". Mild TBI is increasingly recognized as an important public health problem. Despite their designation as "mild", adverse outcomes from such injuries are significant, with 25% of patients still impaired at one year. Visual difficulties are common, reported by two-thirds of patients in a Veterans Administration study. Methods Visual symptoms of mild TBI typically include blurring, light sensitivity, eyestrain, difficulty with near focus, trouble tracking, seeing haloes around lights, and diplopia (monocular and binocular). Results Despite the high incidence of visual symptoms, results of standard eye examination and neuro-ophthalmic testing are typically normal. Conventional neuro-imaging also fails to demonstrate objective evidence of neurologic dysfunction in most cases. Recent developments in neuroimaging (particularly diffusion tensor imaging) and serologic testing (S-100B) have provided some correlates of such injury. Conclusion New information from neuroimaging and serologic testing has helped to provide some objective markers for post-concussive syndromes. The diagnosis of such post-traumatic syndromes remains largely clinical. [source]

    Sensitivity analysis of different methods of coding taxonomic polymorphism: an example from higher-level bat phylogeny

    CLADISTICS, Issue 6 2002
    Nancy B. Simmons
    New information concerning strengths and weaknesses of different methods of coding taxonomic polymorphisms suggests that results of some previous studies may have been unintentionally biased by the methods employed. In this study, we demonstrate that a form of sensitivity analysis can be used to evaluate the effects of different methods of coding taxonomic polymorphisms on the outcome of phylogenetic analyses. Our earlier analysis of higher-level relationships of bats (Mammalia: Chiroptera) employed superspecific taxa as terminals and scored taxonomic polymorphisms using ambiguity coding. Application of other methods of dealing with polymorphisms (excluding variable characters, inferring ancestral states, majority coding) to the same data yields phylogenetic results that differ somewhat from those originally reported based on ambiguity coding. Monophyly of some clades was supported in all analyses (e.g., Microchiroptera, Rhinopomatoidea, and Nataloidea), while other groups found to be monophyletic in the original study (e.g., neotropical Nataloidea) appeared unresolved or nonmonophyletic when other methods were used to code taxonomic polymorphisms. Several groupings that were apparently refuted in the initial study (e.g., Noctilionoidea including Mystacinidae) were supported in some analyses, reducing some of the apparent incongruence between the trees in our earlier analysis (which were based principally on morphology) and other trees based on molecular data. Perceived support for various groupings (branch support, bootstrap values) were in some cases significantly affected by the methods employed. These results indicate that sensitivity analysis provides a useful tool for evaluating effects of different methods of dealing with taxonomic polymorphism in superspecific terminal taxa. Variation in results obtained with different methods suggests that it is always preferable to sample at the species level when higher-level taxa exhibit taxonomic polymorphism, thus avoiding methodological biases associated with different methods of dealing with taxonomic polymorphisms during data analysis. [source]

    Coronary arteries in fetal life: physiology, malformations and the "heart-sparing effect"

    ACTA PAEDIATRICA, Issue 2004
    R ChaouiArticle first published online: 2 JAN 200
    The present knowledge of coronary arteries in prenatal diagnosis is reviewed with a focus on three aspects: the physiology and visualization of coronary flow, malformations involving the coronary arteries, and the "heart-sparing effect". Visualization of coronary arteries in a healthy human fetus is possible in real-time and colour Doppler during the last 10wk of gestation when ultrasound conditions are excellent. Visualization at an earlier gestational age (up to 13 wk) is feasible mainly in association with malformations and impending hypoxia. The main coronary malformations that can be visualized in utero are the ventriculo-coronary communications in fetuses with pulmonary atresia. In the last few years, interest has been focused on the "heart-sparing effect", defined as the increased perfusion of the coronary arteries in fetuses with severe growth restriction and abnormal Doppler velocimetry in the peripheral vessels. Increased perfusion detectable with colour and pulsed Doppler is a late sign of fetal compromise in hypoxaemia. It confirms animal experiments that have demonstrated dilatory reserves of the fetal coronary arteries under chronic hypoxaemia. The outcome of 21 fetuses showing the "heart-sparing effect" before 32 wk gestation was poor: nine fetuses died in utero and two after birth, the median weight at birth was 630 g. In summary, our knowledge of the coronary arteries in the fetus is based on the diagnostic means used in prenatal diagnosis. New information in this field may also contribute to a better understanding of coronary heart disease later in life. [source]

    Connections among Factors in Education

    CURRICULUM INQUIRY, Issue 3 2004
    ABSTRACT There are some long-standing problems in education about the impact of education on the learning of students. These problems may be better documented now and thus better understood as a consequence of the amount of relatively new information and the quality of that information. Perhaps more importantly, this well-documented new information will lead to valid inferences about the problems that the media, the public, educators, and researchers can accept. There are four problems that can help focus the investigation that follows. [source]

    Na+/Ca2+ exchanger modulates the flagellar wave pattern for the regulation of motility activation and chemotaxis in the ascidian spermatozoa

    CYTOSKELETON, Issue 10 2006
    Kogiku Shiba
    Abstract Ion channels and ion exchangers are known to be important participants in various aspects of sperm physiology, e.g. motility activation, chemotaxis, the maintenance of motility and the acrosome reaction in the sperm. We report here on a role of the K+ -independent Na+/Ca2+ exchanger (NCX) on ascidian sperm. Reverse-transcriptase PCR reveals that the NCX is expressed in the testis while immunoblotting and immunolocalization demonstrate that the NCX exists on the sperm in the ascidian Ciona savignyi and C. intestinalis. A potent blocker of the NCX, KB-R7943 was found to block sperm-activating and -attracting factor (SAAF)-induced motility activation, sperm motility and sperm chemotaxis. We further analyzed the effects of this blocker on motility parameters such as the flagellar waveform, curvature, beat frequency, amplitude and wavelength of the sperm flagella. Inhibition of the NCX caused two distinct effects: a low concentration of KB-R7943 induced symmetric bending, whereas a high concentration of KB-R7943 resulted in asymmetric flagellar bending. These findings suggest that the NCX plays important roles in the regulation of SAAF-induced sperm chemotaxis, motility activation and motility maintenance in the ascidian. This study provides new information toward an understanding of Ca2+ transport systems in sperm motility and chemotaxis. Cell Motil. Cytoskeleton 2006. © 2006 Wiley-Liss, Inc. [source]

    Development of swallowing and feeding: Prenatal through first year of life

    Amy L. Delaney
    Abstract The development of feeding and swallowing involves a highly complex set of interactions that begin in embryologic and fetal periods and continue through infancy and early childhood. This article will focus on swallowing and feeding development in infants who are developing normally with a review of some aspects of prenatal development that provide a basis for in utero sucking and swallowing. Non-nutritive sucking in healthy preterm infants, nipple feeding in preterm and term infants, and selected processes of continued development of oral skills for feeding throughout the first year of life will be discussed. Advances in research have provided new information in our understanding of the neurophysiology related to swallowing, premature infants' sucking and swallowing patterns, and changes in patterns from preterm to near term to term infants. Oral skill development as texture changes are made throughout the second half of the first year of life is an under studied phenomenon. Knowledge of normal developmental progression is essential for professionals to appreciate differences from normal in infants and children with feeding and swallowing disorders. Additional research of infants and children who demonstrate overall typical development in oral skills for feeding is encouraged and will provide helpful reference points in increasing understanding of children who exhibit differences from typical development. It is hoped that new technology will provide noninvasive means of delineating all phases of sucking and swallowing from prenatal through infancy. Further related topics in other articles of this issue provide a comprehensive review of factors influencing oral intake, growth, nutrition, and neurodevelopmental status of children. © 2008 Wiley-Liss, Inc. Dev Disabil Res Rev 2008;14:105,117. [source]

    Children's attention to sample composition in learning, teaching and discovery

    Marjorie Rhodes
    Two studies compared children's attention to sample composition , whether a sample provides a diverse representation of a category of interest , during teacher-led and learner-driven learning contexts. In Study 1 (n = 48), 5-year-olds attended to sample composition to make inferences about biological properties only when samples were presented by a knowledgeable teacher. In contrast, adults attended to sample composition in both teacher-led and learner-driven contexts. In Study 2 (n = 51), 6-year-olds chose to create diverse samples to teach information about biological kinds to another child, but not to discover new information for themselves, whereas adults chose to create diverse samples for both teaching and information discovery. Results suggest that how children approach the interpretation and selection of evidence varies depending on whether learning occurs in a pedagogical or a non-pedagogical context. [source]

    Sensitivity to communicative relevance tells young children what to imitate

    Victoria Southgate
    How do children decide which elements of an action demonstration are important to reproduce in the context of an imitation game? We tested whether selective imitation of a demonstrator's actions may be based on the same search for relevance that drives adult interpretation of ostensive communication. Three groups of 18-month-old infants were shown a toy animal either hopping or sliding (action style) into a toy house (action outcome), but the communicative relevance of the action style differed depending on the group. For the no prior information group, all the information in the demonstration was new and so equally relevant. However, for infants in the ostensive prior information group, the potential action outcome was already communicated to the infant prior to the main demonstration, rendering the action style more relevant. Infants in the ostensive prior information group imitated the action style significantly more than infants in the no prior information group, suggesting that the relevance manipulation modulated their interpretation of the action demonstration. A further condition (non-ostensive prior information) confirmed that this sensitivity to new information is only present when the ,old' information had been communicated, and not when infants discovered this information for themselves. These results indicate that, like adults, human infants expect communication to contain relevant content, and imitate action elements that, relative to their current knowledge state or to the common ground with the demonstrator, is identified as most relevant. [source]

    Neural plasticity and human development: the role of early experience in sculpting memory systems

    Charles A. Nelson
    The concept of sensitive or critical periods in the context of memory development is examined in this paper. I begin by providing examples of the role of experience in influencing sensory, linguistic and emotional functioning. This is followed by a discussion of the role of experience in influencing cognitive functioning, particularly memory. Based on this discussion, speculation is offered that the infant's proclivity for novelty, which makes its appearance shortly after birth, provides critical input into a nervous system that will eventually be set up to learn and remember for the entire lifespan. Because learning and memory are fundamental to the survival of our species, those aspects of the nervous system that permit the encoding and retention of new information are remarkably malleable from the outset, even in the face of some types of neural trauma. This flexibility is retained for many years so long as the learning and memory ,system' is challenged. The implications of this model are discussed in the context of those life events that might undermine the longevity of memory systems. [source]

    Morphology and histology of the larynx of the common toad Rhinella arenarum (Hensel, 1867) (Anura, Bufonidae)

    ACTA ZOOLOGICA, Issue 4 2009
    Gladys N. Hermida
    Abstract The structure of the larynx of the toad Rhinella arenarum was exhaustively studied. The laryngeal skeleton consists of three bilaterally symmetrical cartilages: the cricoid and two arytenoids. Internally, each half-larynx has an anterior and a posterior chamber. The first chamber is delimited by the epithelium covering the arytenoid cartilage and the anterior membrane. The latter consists of fibro-elastic tissue and contains blood capillaries that, judging by their location and distribution, might serve to maintain vocal cord turgidity. At the level of the cricoid cartilage, two structures are reported here for the first time: the posterodorsal and the anteroventral processes. Both processes are associated with the insertion of the posterior membrane. A cartilaginous rod is located at the free margin of the posterior membrane. This rod appears to support the membrane when the air flows. The distal portion of the larynx communicates with the proximal region of the lung. The epithelium of the laryngeal mucosa contains ciliated cells, goblet cells, secretory cells with short microvilli and neuroendocrine cells immunopositive to PGP 9.5. The results obtained in this study provide new information about the internal organization of the larynx in anurans, which could serve as additional morphological characters for phylogenetic relationships. [source]

    Genetic diversity of endangered brown bear (Ursus arctos) populations at the crossroads of Europe, Asia and Africa

    Sébastien Calvignac
    Abstract Aim, Middle East brown bears (Ursus arctos syriacus Hemprich and Ehrenberg, 1828) are presently on the edge of extinction. However, little is known of their genetic diversity. This study investigates that question as well as that of Middle East brown bear relationships to surrounding populations of the species. Location, Middle East region of south-western Asia. Methods, We performed DNA analyses on 27 brown bear individuals. Twenty ancient bone samples (Late Pleistocene to 20th century) from natural populations and seven present-day samples obtained from captive individuals were analysed. Results, Phylogenetic analyses of the mitochondrial sequences obtained from seven ancient specimens identify three distinct maternal clades, all unrelated to one recently described from North Africa. Brown bears from Iran exhibit striking diversity (three individuals, three haplotypes) and form a unique clade that cannot be linked to any extant one. Individuals from Syria belong to the Holarctic clade now observed in Eastern Europe, Turkey, Japan and North America. Specimens from Lebanon surprisingly appear as tightly linked to the clade of brown bears now in Western Europe. Moreover, we show that U. a. syriacus in captivity still harbour haplotypes closely linked to those found in ancient individuals. Main conclusion, This study brings important new information on the genetic diversity of brown bear populations at the crossroads of Europe, Asia and Africa. It reveals a high level of diversity in Middle East brown bears and extends the historical distribution of the Western European clade to the East. Our analyses also suggest the value of a specific breeding programme for captive populations. [source]

    Regional assessment of the impact of climatic change on the distribution of a tropical conifer in the lowlands of South America

    Marie-Pierre Ledru
    Abstract For decades, palynologists working in tropical South America are using the genus Podocarpus as a climate indicator although without referring to any modern data concerning its distribution and limiting factors. With the aim to characterize the modern and past distribution of the southern conifer Podocarpus in Brazil and to obtain new information on the distribution of the Atlantic rainforest during the Quaternary, we examined herbarium data to locate the populations of three Brazilian endemic Podocarpus species: P. sellowii, P. lambertii, and P. brasiliensis, and extracted DNA from fresh leaves from 26 populations. Our conclusions are drawn in the light of the combination of these three disciplines: botany, palynology, and genetics. We find that the modern distribution of endemic Podocarpus populations shows that they are widely dispersed in eastern Brazil, from north to south and reveals that the expansion of Podocarpus recorded in single Amazonian pollen records may have come from either western or eastern populations. Genetic analysis enabled us to delimit regional expansion: between 5° and 15° S grouping northern and central populations of P. sellowii expanded c. 16,000 years ago; between 15° and 23° S populations of either P. lambertii or sellowii expanded at different times since at least the last glaciation; and between 23° and 30° S, P. lambertii appeared during the recent expansion of the Araucaria forest. The combination of botany, pollen, and molecular analysis proved to be a rapid tool for inferring distribution borders for sparse populations and their regional evolution within tropical ecosystems. Today the refugia of rainforest communities we identified are crucial hotspots to allow the Atlantic forest to survive under unfavourable climatic conditions and, as such, offer the only possible opportunity for this type of forest to expand in the event of a future climate change. [source]

    Disclosures and Asset Returns

    ECONOMETRICA, Issue 1 2003
    Hyun Song Shin
    Public information in financial markets often arrives through the disclosures of interested parties who have a material interest in the reactions of the market to the new information. When the strategic interaction between the sender and the receiver is formalized as a disclosure game with verifiable reports, equilibrium prices can be given a simple characterization in terms of the concatenation of binomial pricing trees. There are a number of empirical implications. The theory predicts that the return variance following a poor disclosed outcome is higher than it would have been if the disclosed outcome were good. Also, when investors are risk averse, this leads to negative serial correlation of asset returns. Other points of contact with the empirical literature are discussed. [source]

    Chronic toxicity and responses of several important enzymes in Daphnia magna on exposure to sublethal microcystin-LR

    Wei Chen
    Abstract In the current study, the toxicological mechanisms of microcystin-LR and its disadvantageous effects on Daphnia magna were examined. Survival rate, number of newborn, activity of several important enzymes [glutathione S-transferase (GST), lactate dehydrogenase (LDH), phosphatases, and glutathione], accumulated microcystins, and ultrastructural changes in different organs of Daphnia were monitored over the course of 21-day chronic tests. The results indicated that low concentrations of dissolved microcystin had no harmful effect on Daphnia. On the contrary, stimulatory effects were detected. In the presence of toxin at high dosage and for long-term exposure, GST and glutathione levels decreased significantly. The decreased enzyme activity in the antioxidant system probably was caused by detoxification reactions with toxins. And these processes of detoxification at the beginning of chronic tests may enable phosphatases in Daphnia magna to withstand inhibition by the toxins. At the same time, we also found that the LDH activity in test animals increased with exposure to microcystin-LR, indicating that adverse effects occurred in Daphnia. With microcystin given at a higher dosage or for a longer exposure, the effect on Daphnia magna was fatal. In the meantime, microcystin began to accumulate in Daphnia magna, and phosphatase activity started to be inhibited. From the ultrastructure results of cells in D. magna, we obtained new information: the alimentary canal may be the target organ affected by exposure of microcystins to D. magna. The results of the current study also suggested that the oxidative damage and PPI (protein phosphatase inhibition) mechanisms of vertebrates also are adapted to Daphnia. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 323,330, 2005. [source]

    Why do we need an Addiction supplement focused on methamphetamine?

    ADDICTION, Issue 2007
    Richard A. Rawson
    ABSTRACT Methamphetamine is a substantial public health problem in many communities in the United States and in other parts of the world. In order to bring new knowledge about methamphetamine to policy makers, clinicians and researchers, this volume has compiled a set of articles containing new information about the drug and its effects. The articles contain information presented by researchers at two special methamphetamine meetings sponsored by the National Institute on Drug Abuse in 2005. [source]

    European Momentum Strategies, Information Diffusion, and Investor Conservatism

    John A. Doukas
    G1; G11; G14 Abstract In this paper we conduct an out-of-sample test of two behavioural theories that have been proposed to explain momentum in stock returns. We test the gradual-information-diffusion model of Hong and Stein (1999) and the investor conservatism bias model of Barberis et al. (1998) in a sample of 13 European stock markets during the period 1988 to 2001. These two models predict that momentum comes from the (i) gradual dissemination of firm-specific information and (ii) investors' failure to update their beliefs sufficiently when they observe new public information. The findings of this study are consistent with the predictions of the behavioural models of Hong and Stein's (1999) and Barberis et al. (1998). The evidence shows that momentum is the result of the gradual diffusion of private information and investors' psychological conservatism reflected on the systematic errors they make in forming earnings expectations by not updating them adequately relative to their prior beliefs and by undervaluing the statistical weight of new information. [source]