950 research outputs found

    Determination of the cosmic-ray-induced neutron flux and ambient dose equivalent at flight altitude

    Get PDF
    Journal of Physics: Conference Series, Volumen 630There is interest in modeling the atmosphere in the South Atlantic Magnetic Anomaly in order to obtain information about the cosmic-ray induced neutron spectrum and angular distribution as functions of altitude. In this work we use the Monte Carlo codes MCNPX and Geant4 to determine the cosmic-ray-induced neutron flux in the atmosphere produced by the cosmic ray protons incident on the top of the atmosphere and to estimate the ambient dose equivalent rate as function of altitude. The results present a reasonable conformity to other codes (QARM and EXPACS) based on other parameterizations

    Mouse Models of Genomic Syndromes as Tools for Understanding the Basis of Complex Traits: An Example with the Smith-Magenis and the Potocki-Lupski Syndromes

    Get PDF
    Each human's genome is distinguished by extra and missing DNA that can be “benign” or powerfully impact everything from development to disease. In the case of genomic disorders DNA rearrangements, such as deletions or duplications, correlate with a clinical specific phenotype. The clinical presentations of genomic disorders were thought to result from altered gene copy number of physically linked dosage sensitive genes. Genomic disorders are frequent diseases (~1 per 1,000 births). Smith-Magenis syndrome (SMS) and Potocki-Lupski syndrome (PTLS) are genomic disorders, associated with a deletion and a duplication, of 3.7 Mb respectively, within chromosome 17 band p11.2. This region includes 23 genes. Both syndromes have complex and distinctive phenotypes including multiple congenital and neurobehavioral abnormalities. Human chromosome 17p11.2 is syntenic to the 32-34 cM region of murine chromosome 11. The number and order of the genes are highly conserved. In this review, we will exemplify how genomic disorders can be modeled in mice and the advantages that such models can give in the study of genomic disorders in particular and gene copy number variation (CNV) in general. The contributions of the SMS and PTLS animal models in several aspects ranging from more specific ones, as the definition of the clinical aspects of the human clinical spectrum, the identification of dosage sensitive genes related to the human syndromes, to the more general contributions as the definition of genetic locus impacting obesity and behavior and the elucidation of general mechanisms related to the pathogenesis of gene CNV are discussed

    Palaeoenvironmental turnover across the Cenomanian-Turonian transition in Oued Bahloul, Tunisia: Foraminifera and geochemical proxies

    Get PDF
    The integrated analysis of foraminiferal assemblages, geochemical proxies, and stable isotopes in the Oued Bahloul section (Tunisia) allowed us to reconstruct the environmental turnover across the Cenomanian–Turonian boundary. An increase in palaeoproductivity proxies (P/Ti, U/Al, Sr/Al) and in d13C values, and a decrease in foraminiferal diversity and d18O values mark the beginning of the Oceanic Anoxic Event 2 (OAE2) at the Rotalipora cushmani and Whiteinella archaeocretacea biozones boundary. Eutrophic conditions at the seafloor and in the water column are evidenced by high proportions of buliminids and the replacement of planktic oligotrophic specialist Rotalipora by eutrophic opportunist Hedbergella. The enrichment in organic matter and redox sensitive elements, together with the abundance of low-oxygen tolerant benthic foraminifera, indicate dysoxic conditions in the deep-water column and at the seafloor (higher Uaut than Moaut). Among planktic foraminifera, deep- and intermediate-dwellers disappear (Rotalipora and Globigerinelloides), and surface-dwellers proliferate (Hedbergella). The persistency of the poorly oxygenated conditions during the W. archaeocretacea Biozone locally produced euxinic conditions where MoEF and Moaut reach high values, diversity presents minimum values, and benthic foraminifera temporarily disappear. The maximum percentage of heterohelicids indicates a stratified water column with a well-developed oxygen minimum zone. Improved oxygen conditions returned in the upper part of the W. archaeocretacea Biozone and Helvetoglobotruncana helvetica Biozone, with a slow recovery of foraminiferal assemblages, decrease in eutrophic genera (Heterohelix) and increase in mesotrophic genera (Whiteinella). A gradual increase in d18O values suggests decreased temperatures in surface waters. The OAE2 has been attributed to global temperature changes and palaeoceanographic reorganization. The poor mixing of surface and deep waters and enhanced primary productivity related to global warming – associated with increasing continental weathering and nutrient runoff – may have favored the eutrophication of the ocean and the expansion of the oxygen minimum zone

    Retardo Temporal En Las Lentes Por Galaxias En El Contexto De Reissner - Nordstrom

    Get PDF
    In this work we derive the mathematical expressions for the time delay between two images due to gravitational lensing with symmetric distributions of both: mass and electric charge from the line element in the context of Reissner-Nordstrom (RN). For this, is important to study the motion of photons that are curved around the mass distribution charged by RN metric, obtaining expressions for the deflection angle and deflection potential studying the phenomenon of so much for a lensing precise mass to mass distribution. Then applied the results, the singular sphere model isotherm (ESI), and compared with those in which only considers galaxies mass distribution. But, that this expression of the time delay is applicable to any gravitational lens model loaded too

    The biology and behavior of the longhorned beetle, Dectes texanus on sunflower and soybean

    Get PDF
    The biology and behavior of the longhorned beetle Dectes texanus LeConte (Coleoptera: Cerambycidae) was studied on two host plants that suffer economic losses from this pest; sunflower, Helianthus annuus, and soybean, Glycines max. Reciprocal crosses of D. texanus collected from the two plants all produced viable progeny, indicating that conspecific insects attack both crops. Pupae from soybean stalks weighed about 40% less than those from sunflower, and adults fed on soybean lived a mean of 23 days, compared to a mean of 53 days (males) and 76 days (females) for those fed sunflower. A female's larval host plant had no effect on her tendency to ovipuncture plants of either type in a greenhouse trial. A field-tested population collected exclusively from sunflower contained three types of females in similar proportions: those that laid eggs only on sunflower, those that laid only on soybean, and those that laid equally on both host plants. Females in field trials fed more on the plant they had fed on in the laboratory, but soybean-fed females fed more on soybean than did sunflower-fed females. Females fed soybean also made more ovipunctures on soybean plants in field trials than sunflower-fed females, but their responses to sunflower plants were similar. Females displayed higher total ovipositional activity when they encountered sunflower first in the field, and lower total activity when they encountered soybean first. Feeding scores were significantly correlated with ovipunctures and eggs on both plant types. We conclude that sunflower is the preferred host plant, although females will accept soybean when it is the only available food. The results suggest that D. texanus is still in the initial stages of a host range expansion with female host selection behavior demonstrating both genetic influences and phenotypic flexibility. Sunflower represents a nutritionally superior, ancestral host plant and relatively high fitness costs are still associated with utilization of the novel host plant, soybean, costs that may be offset by benefits such as reduced intraspecific competition. These potential benefits and their consequent implications for D. texanus host range evolution are hypothesized and discussed

    Clinical and ultrasound thyroid nodule characteristics and their association with cytological and histopathological outcomes: A retrospective multicenter study in high-resolution thyroid nodule clinics

    Get PDF
    Introduction: Thyroid nodules are a common finding. A high-resolution thyroid nodule clinic (HR-TNC) condenses all tests required for the evaluation of thyroid nodules into a single appointment. We aimed to evaluate the clinical outcomes at HR-TNCs. Design and Methods: A retrospective cross-sectional multicenter study including data from four HR-TNCs in Spain. We evaluated fine-needle aspiration (FNA) indications and the association between clinical and ultrasound characteristics with cytological and histopathological outcomes. Results: A total of 2809 thyroid nodules were included; FNA was performed in 82.1%. Thyroid nodules that underwent FNA were more likely larger, isoechoic, with microcalcifications, and in younger subjects. The rate of nondiagnostic FNA was 4.3%. A solid component, irregular margins or microcalcifications, significantly increased the odds of Bethesda IV-V-VI (vs. Bethesda II). Irregular margins and a solid component were independently associated with increased odds of malignancy. Thyroid nodules <20 mm and ≄20–<40 mm had a 6.5-fold and 3.3-fold increased risk for malignancy respectively in comparison with those ≄40 mm. Conclusion: In this large multicenter study, we found that the presence of a solid component and irregular margins are factors independently related to malignancy in thyroid nodules. Since nodule size ≄40 mm was associated with the lowest odds of malignancy, this cut-off should not be a factor leading to indicate thyroid surgery. HR-TNCs were associated with a low rate of nondiagnostic FNA

    Changes of Several Psychological Measures in the Patients with Craniomandibular Disorders, Bruxing Behavior and Sexual Abuse History

    Get PDF
    Aim: The understanding of psychological correlates of Craniomandibular disorders and Bruxing Behavior has seen significant progress in the last few years. However, studies evaluating association between more complex psychological measures in such disorders are extremely scarce. To investigate this, we evaluated frequency of sexual abuse history in the experimental and two control groups and scores in depression, somatization and dissociation in those with Craniomandibular Disorders and Bruxism with/without sexual abuse history.Methods: Clinical examination, self-report, chief complaint, criteria for craniomandibular disorders and bruxism, the Becker-Lausen Questionnaire for sexual abuse were used in the Craniomandibular Disorder+ Bruxing Behavior, and in two control subgroups to gather data about sexual abuse history. The Beck Depression Inventory (BDI), 32 questions from the Screening Somatoform Disorders (SOMS-2) instrument and the Dissociative Experience Scale (DES) were used in the Craniomandibular Disorder + Bruxism + Sexual Abuse (n=39), in the Craniomandibular Disorder + Bruxism with no sexual abuse subgroup (n=158) and in the no Craniomandibular Disorders no Sexual Abuse subgroup (n=50) so as to gather data about depression, somatization and dissociation, respectively.Results: We show that there was no a statistically significant difference when comparing frequency of sexual abuse history in the experimental and in the two control groups. Means in depression were about 14.7; 11.4; and 9.3 in the Craniomandibular Disorder + Bruxism and Sexual abuse, in the Craniomandibular Disorder + Bruxism with no sexual abuse history, and in the no Craniomandibular Disorders no Sexual abuse history subgroups, respectively (Kruskall-Wallis statistics with post test p&lt;0.02). Means in somatization were 12.1, 10.3, and 8.0, respectively in those subgroups (p&lt;0.006). Means in dissociation were about 22.3, 15.6, and 15.2, respectively (p&lt;0.007).Conclusions: Means in depression, somatization and dissociation were higher and significantly different in the Craniomandibular + bruxing behavior + sexual abuse history subgroup. This study provides further data on frequency of sexual abuse in craniomandibular disorder and bruxer subjects, expands current knowledge about depression and somatization and provides non previously reported data on dissociation

    Contourite depositional system after the exit of a strait: Case study from the late Miocene South Rifian Corridor, Morocco

    Get PDF
    Idealized facies of bottom current deposits (contourites) have been established for fine-grained contourite drifts in modern deep-marine sedimentary environments. Their equivalent facies in the ancient record however are only scarcely recognized due to the weathered nature of most fine-grained deposits in outcrop. Facies related to the erosional elements (i.e. contourite channels) of contourite depositional systems have not yet been properly established and related deposits in outcrop appear non-existent. To better understand the sedimentary facies and facies sequences of contourites, the upper Miocene contourite depositional systems of the South Rifian Corridor (Morocco) is investigated. This contourite depositional system formed by the dense palaeo-Mediterranean Outflow Water. Foraminifera assemblages were used for age-constraints (7.51 to 7.35 Ma) and to determine the continental slope depositional domains. Nine sedimentary facies have been recognized based on lithology, grain-size, sedimentary structures and biogenic structures. These facies were subsequently grouped into five facies associations related to the main interpreted depositional processes (hemipelagic settling, contour currents and gravity flows). The vertical sedimentary facies succession records the tectonically induced, southward migration of the contourite depositional systems and the intermittent behaviour of the palaeo-Mediterranean Outflow Water, which is mainly driven by precession and millennial-scale climate variations. Tides substantially modulated the palaeo-Mediterranean Outflow Water on a sub-annual scale. This work shows exceptional examples of muddy and sandy contourite deposits in outcrop by which a facies distribution model from the proximal continental slope, the contourite channel to its adjacent contourite drift, is proposed. This model serves as a reference for contourite recognition both in modern environments and the ancient record. Furthermore, by establishing the hydrodynamics of overflow behaviour a framework is provided that improves process-based interpretation of deep-water bottom current deposits

    ParadisEO-MOEO: A Software Framework for Evolutionary Multi-Objective Optimization

    Get PDF
    This chapter presents ParadisEO-MOEO, a white-box object-oriented software framework dedicated to the flexible design of metaheuristics for multi-objective optimization. This paradigm-free software proposes a unified view for major evolutionary multi-objective metaheuristics. It embeds some features and techniques for multi-objective resolution and aims to provide a set of classes allowing to ease and speed up the development of computationally efficient programs. It is based on a clear conceptual distinction between the solution methods and the problems they are intended to solve. This separation confers a maximum design and code reuse. This general-purpose framework provides a broad range of fitness assignment strategies, the most common diversity preservation mechanisms, some elitistrelated features as well as statistical tools. Furthermore, a number of state-of-the-art search methods, including NSGA-II, SPEA2 and IBEA, have been implemented in a user-friendly way, based on the fine-grained ParadisEO-MOEO components
    • 

    corecore