648 research outputs found

    Item response modeling of DSM-IV mania symptoms in two representative US epidemiological samples

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    BACKGROUND: There is considerable debate surrounding the effective measurement of DSM-IV symptoms used to assess manic disorders in epidemiological samples. METHODS: Using two nationally representative datasets, the National Epidemiological Survey of Alcohol and Related Conditions (NESARC, N=43,093 at Wave 1, N=34,653 at 3-year follow-up) and the National Comorbidity Survey-Replication (NCS-R, N=9,282), we examined the psychometric properties of symptoms used to assess DSM-IV mania. The predictive utility of the mania factor score was tested using the 3-year follow-up data in NESARC. RESULTS: Criterion B symptoms were unidimensional (single factor) in both samples. The symptoms assessing flight of ideas, distractibility and increased goal-directed activities had high factor loadings (0.70–0.93) with moderate rates of endorsement thus providing good discrimination between individuals with and without mania. The symptom assessing grandiosity performed less well in both samples. The quantitative mania factor score was a good predictor of more severe disorders at 3-year follow-up in the NESARC sample, even after controlling for a past history of DSM-IV diagnosis of manic disorder. CONCLUSION: These analyses suggest that questions based on some DSM symptoms effectively discriminate between individuals at high and low liability to mania, while others do not. A quantitative mania factor score may aid in predicting recurrence for patients with a history of mania. Methods for assessing mania using structured interviews in the absence of clinical assessment require further refinement

    O PAPEL DO TIPO DE RESPOSTA NA FORMA DO CONTRASTE NEGATIVO OU DA INDUÇÃO POSITIVA EM RATOS

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    Rats may decrease (negative contrast) or increase (positive induction) their rate of responding for 1% sucrose reinforcement when 32% sucrose reinforcement is upcoming under different conditions. Previous research suggests that which effect occurs may depend on what motor response (i.e., licking vs. press a lever) isrequired to obtain the sucrose. The present study investigated this idea by having subjects make different responses in different halves of the session. Subjects either licked or pressed a lever for 1% sucrose reinforcement in the first half of the session. They then made the alternative response for 1% or 32% sucrose reinforcement, in different conditions, in the second half. In Experiment 1, both licking and lever pressing were operant responses. In Experiment 2, licking was strictly a consummatory response. Results showed that upcoming 32% sucrose tended to decrease responding for 1% sucrose in the first half of the session regardless of the response required in either half. Positive induction was never observed. The present results question whether type of motor response is a key factor in whether contrast or induction is observed. Instead, they suggest that the location that thesubstances are delivered and consumed is critical. Ultimately, understanding when one effect or the other will occur will enhance our understanding of eating-related behavior.Key words: negative contrast, positive induction, reinforcement, lever press, rat.Ratos podem diminuir (contraste negativo) ou aumentar (indução positiva) sua taxa de respostas reforçadas com solução de sacarose a 1% quando reforçamento com solução de sacarose a 32% é iminente, em diferentes condições. Pesquisa anterior sugere que o efeito que ocorrerá pode depender de qual resposta motora (lamber versus pressionar a barra, por exemplo) é requerida para obter a solução de sacarose. O presente estudo investigou esse problema fazendo os sujeitos emitirem respostas diferentes em cada uma das metades das sessões. Os sujeitos ou lambiam ou pressionavam uma barra e produziam reforçamento de solução de sacarose a 1% na primeira metade da sessão. Eles emitiam, então, a resposta alternativa, reforçada por solução de sacarose a 1% ou 32%, em condições diferentes, na segunda metade da sessão. No Experimento 1, ambos, lamber e pressionar a barra eram respostas operantes. No Experimento 2, lamber foi uma resposta estritamente consumatória. Os resultados mostraram que a solução de sacarose a 32% iminente tendeu a diminuir o responder por solução de sacarose a 1% na primeira metade da sessão, independentemente de qual era a resposta requerida na outra metade. Indução positiva nunca foi observada. Os resultados presentes questionam se o tipo de resposta motora seria um fator chave para a observação de contraste ou de indução, sugerindo, ao contrário, que o local em que as substâncias são liberadas e consumidas seja crítico. Compreender quando um efeito ou outro vai ocorrer aumentará nossa compreensão do comportamento relacionado com alimentar-se. Palavras-chave: Contraste negativo, indução positiva, reforçamento, pressão à barra, rato

    Simulation of patch and slot antennas using FEM with prismatic elements and investigations of artificial absorber mesh termination schemes

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    Year 1 progress can be characterized with four major achievements which are crucial toward the development of robust, easy to use antenna analysis code on doubly conformal platforms. (1) A new FEM code was developed using prismatic meshes. This code is based on a new edge based distorted prism and is particularly attractive for growing meshes associated with printed slot and patch antennas on doubly conformal platforms. It is anticipated that this technology will lead to interactive, simple to use codes for a large class of antenna geometries. Moreover, the codes can be expanded to include modeling of the circuit characteristics. An attached report describes the theory and validation of the new prismatic code using reference calculations and measured data collected at the NASA Langley facilities. The agreement between the measured and calculated data is impressive even for the coated patch configuration. (2) A scheme was developed for improved feed modeling in the context of FEM. A new approach based on the voltage continuity condition was devised and successfully tested in modeling coax cables and aperture fed antennas. An important aspect of this new feed modeling approach is the ability to completely separate the feed and antenna mesh regions. In this manner, different elements can be used in each of the regions leading to substantially improved accuracy and meshing simplicity. (3) A most important development this year has been the introduction of the perfectly matched interface (PMI) layer for truncating finite element meshes. So far the robust boundary integral method has been used for truncating the finite element meshes. However, this approach is not suitable for antennas on nonplanar platforms. The PMI layer is a lossy anisotropic absorber with zero reflection at its interface. (4) We were able to interface our antenna code FEMA_CYL (for antennas on cylindrical platforms) with a standard high frequency code. This interface was achieved by first generating equivalent magnetic currents across the antenna aperture using the FEM code. These currents were employed as the sources in the high frequency code

    Simulation of Conformal Spiral Slot Antennas on Composite Platforms

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    During the course of the grant, we wrote and distributed about 12 reports and an equal number of journal papers supported fully or in part by this grant. The list of reports (title & abstract) and papers are given in Appendices A and B. This grant has indeed been instrumental in developing a robust hybrid finite element method for the analysis of complex broadband antennas on doubly curved platforms. Previous to the grant, our capability was limited to simple printed patch antennas on mostly planar platforms. More specifically: (1) mixed element formulations were developed and new edge-based prisms were introduced; (2) these elements were important in permitting flexibility in geometry gridding for most antennas of interest; (3) new perfectly matched absorbers were introduced for mesh truncations associated with highly curved surfaces; (4) fast integral algorithms were introduced for boundary integral truncations reducing CPU time from O(N-2) down to O(N-1.5) or less; (5) frequency extrapolation schemes were developed for efficient broadband performance evaluations. This activity has been successfully continued by NASA researchers; (6) computer codes were developed and extensively tested for several broadband configurations. These include FEMA-CYL, FEMA-PRISM and FEMA-TETRA written by L. Kempel, T. Ozdemir and J. Gong, respectively; (7) a new infinite balun feed was designed nearly constant impedance over the 800-3000 MHz operational band; (8) a complete slot spiral antenna was developed, fabricated and tested at NASA Langley. This new design is a culmination of the projects goals and integrates the computational and experimental efforts. this antenna design resulted in a U.S. patent and was revised three times to achieve the desired bandwidth and gain requirements from 800-3000 MHz

    Constraints on the Circumstellar Disk Masses in the IC 348 Cluster

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    A 5.2' x 5.2' region toward the young cluster IC 348 has been imaged in the millimeter continuum at 4.0" x 4.9" resolution with the OVRO interferometer to a RMS noise level of 0.75 mJy/beam at 98 GHz. The data are used to constrain the circumstellar disk masses in a cluster environment at an age of about 2 Myr. The mosaic encompasses 95 known members of the IC 348 cluster with a stellar mass distribution that peaks at 0.2-0.5 Msun. None of the stars are detected in the millimeter continuum at an intensity level of 3 sigma or greater. The mean observed flux for the ensemble of 95 stars is 0.22 +/- 0.08 mJy. Assuming a dust temperature of 20 K, a mass opacity coefficient of kappa_o = 0.02 cm^2/g at 1300 um, and a power law index of beta=1 for the particle emissivity, these observations imply that the 3 sigma upper limit to the disk mass around any individual star is 0.025 Msun, and that the average disk mass is 0.002 +/- 0.001 Msun. The absence of disks with masses in excess of 0.025 Msun in IC 348 is different at the about 3 sigma confidence level from Taurus, where about 14% of the stars in an optically selected sample have such disk masses. Compared with the minimum mass needed to form the planets in our solar system (about 0.01 Msun), the lack of massive disks and the low mean disk mass in IC 348 suggest either that planets more massive than a few Jupiter masses will form infrequently around 0.2-0.5 Msun stars in IC 348, or that the process to form such planets has significantly depleted the disk of small dust grains on time scales less than the cluster age of about 2 Myr.Comment: accepted by A

    Is there a genetic relationship between alcoholism and depression?

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    The Collaborative Study on the Genetics of Alcoholism (COGA) seeks to identify genes contributing to alcoholism and related traits (i.e., phenotypes), including depression. Among alcoholic subjects the COGA study found an increased prevalence of depressive syndrome (i.e., depression that may or may not occur in conjunction with increased drinking). This combination of alcoholism and depression tends to run in families. Comorbid alcoholism and depression occurred substantially more often in first-degree relatives of COGA participants with alcoholism than in relatives of control participants. Based on these data, COGA investigators defined three phenotypes—“alcoholism,” “alcoholism and depression,” and “alcoholism or depression”—and analyzed whether these phenotypes were linked to specific chromosomal regions. These analyses found that the “alcoholism or depression” phenotype showed significant evidence for genetic linkage to an area on chromosome 1. This suggests that a gene or genes on chromosome 1 may predispose some people to alcoholism and others to depression (which may be alcohol induced)

    Interferometric Observations of the T Tauri Stars in the MBM 12 Cloud

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    We have carried out a millimeter interferometric continuum survey toward 7 YSOs in the MBM 12 cloud. Thermal emissions associated with 2 YSOs were detected above the 3-σ\sigma level at 2.1 mm, and one also showed a 1.3 mm thermal emission. Another object was marginally detected at 2.1 mm. Spectral energy distributions of the YSOs are well fitted by a simple power-law disk model. Masses of the circumstellar disks are estimated to be an order of 0.05 M_{\sun}. The circumstellar disks in the MBM 12 cloud have properties in common with the disks in nearby star-forming regions, in terms of disk parameters such as a disk mass, as well as an infrared excess.Comment: 9 pages, 3 figures, accepted by ApJ Letter

    Molecular basis for functional diversity among microbial Nep1-like proteins

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    Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by several phytopathogenic microorganisms. They trigger necrosis in various eudicot plants upon binding to plant sphingolipid glycosylinositol phosphorylceramides (GIPC). Interestingly, HaNLP3 from the obligate biotroph oomycete Hyaloperonospora arabidopsidis does not induce necrosis. We determined the crystal structure of HaNLP3 and showed that it adopts the NLP fold. However, the conformations of the loops surrounding the GIPC headgroup-binding cavity differ from those of cytotoxic Pythium aphanidermatum NLPPya. Essential dynamics extracted from \u3bcs-long molecular dynamics (MD) simulations reveals a limited conformational plasticity of the GIPC-binding cavity in HaNLP3 relative to toxic NLPs. This likely precludes HaNLP3 binding to GIPCs, which is the underlying reason for the lack of toxicity. This study reveals that mutations at key protein regions cause a switch between nontoxic and toxic phenotypes within the same protein scaffold. Altogether, these data provide evidence that protein flexibility is a distinguishing trait of toxic NLPs and highlight structural determinants for a potential functional diversification of non-toxic NLPs utilized by biotrophic plant pathogens
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