1,835 research outputs found

    Multilayer and conformal antennas using synthetic dielectric substrates

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    Transcranial alternating current stimulation at 10 Hz modulates response bias in the Somatic Signal Detection Task

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    Ongoing, pre-stimulus oscillatory activity in the 8-13 Hz alpha range has been shown to correlate with both true and false reports of peri-threshold somatosensory stimuli. However, to directly test the role of such oscillatory activity in behaviour, it is necessary to manipulate it. Transcranial alternating current stimulation (tACS) offers a method of directly manipulating oscillatory brain activity using a sinusoidal current passed to the scalp. We tested whether alpha tACS would change somatosensory sensitivity or response bias in a signal detection task in order to test whether alpha oscillations have a causal role in behaviour. Active 10 Hz tACS or sham stimulation was applied using electrodes placed bilaterally at positions CP3 and CP4 of the 10-20 electrode placement system. Participants performed the Somatic Signal Detection Task (SSDT), in which they must detect brief somatosensory targets delivered at their detection threshold. These targets are sometimes accompanied by a light flash, which could also occur alone. Active tACS did not modulate sensitivity to targets but did modulate response criterion. Specifically, we found that active stimulation generally increased touch reporting rates, but particularly increased responding on light trials. Stimulation did not interact with the presence of touch, and thus increased both hits and false alarms. ACS stimulation increased reports of touch in a manner consistent with our observational reports, changing response bias, and consistent with a role for alpha activity in somatosensory detection

    The bipolar disorder risk allele at CACNA1C also confers risk of recurrent major depression and of schizophrenia

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    Molecular genetic analysis offers opportunities to advance our understanding of the nosological relationship between psychiatric diagnostic categories in general, and the mood and psychotic disorders in particular. Strong evidence (P=7.0 × 10−7) of association at the polymorphism rs1006737 (within CACNA1C, the gene encoding the α-1C subunit of the L-type voltage-gated calcium channel) with the risk of bipolar disorder (BD) has recently been reported in a meta-analysis of three genome-wide association studies of BD, including our BD sample (N=1868) studied within the Wellcome Trust Case Control Consortium. Here, we have used our UK case samples of recurrent major depression (N=1196) and schizophrenia (N=479) and UK non-psychiatric comparison groups (N=15316) to examine the spectrum of phenotypic effect of the bipolar risk allele at rs1006737. We found that the risk allele conferred increased risk for schizophrenia (P=0.034) and recurrent major depression (P=0.013) with similar effect sizes to those previously observed in BD (allelic odds ratio ∼1.15). Our findings are evidence of some degree of overlap in the biological underpinnings of susceptibility to mental illness across the clinical spectrum of mood and psychotic disorders, and show that at least some loci can have a relatively general effect on susceptibility to diagnostic categories, as currently defined. Our findings will contribute to a better understanding of the pathogenesis of major psychiatric illness, and such knowledge should be useful in providing an etiological rationale for shaping psychiatric nosology, which is currently reliant entirely on descriptive clinical data

    Structural subnetwork evolution across the life-span: rich-club, feeder, seeder

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    The impact of developmental and aging processes on brain connectivity and the connectome has been widely studied. Network theoretical measures and certain topological principles are computed from the entire brain, however there is a need to separate and understand the underlying subnetworks which contribute towards these observed holistic connectomic alterations. One organizational principle is the rich-club - a core subnetwork of brain regions that are strongly connected, forming a high-cost, high-capacity backbone that is critical for effective communication in the network. Investigations primarily focus on its alterations with disease and age. Here, we present a systematic analysis of not only the rich-club, but also other subnetworks derived from this backbone - namely feeder and seeder subnetworks. Our analysis is applied to structural connectomes in a normal cohort from a large, publicly available lifespan study. We demonstrate changes in rich-club membership with age alongside a shift in importance from 'peripheral' seeder to feeder subnetworks. Our results show a refinement within the rich-club structure (increase in transitivity and betweenness centrality), as well as increased efficiency in the feeder subnetwork and decreased measures of network integration and segregation in the seeder subnetwork. These results demonstrate the different developmental patterns when analyzing the connectome stratified according to its rich-club and the potential of utilizing this subnetwork analysis to reveal the evolution of brain architectural alterations across the life-span

    Ceratoscopelus maderensis : pecular sound-scattering layer identified with this myctophid fish

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    Reprint. Science, vol. 160, no. 3831, 1968, pp. 991-993. Originally issued as Reference No. 68-58, series later renamed WHOI-.A sound- scattering layer, composed of discrete hyperbolic echo-sequences and apparently restricted to the Slope Water region of the western North Atlantic, has been identified from the Deep Submergence Research Vehicle ALVIN with schools of the myctophid fish Ceratoscopelus maderensis. By diving into the layer and using ALVIN's echo-ranging sonar, we approached and visually identified the sound scatterers. The number of echo sequences observed with the surface echo-sounder (1 /23. 76 x 105 cubic meters of water) checked roughly with the number of sonar targets observed from the submarine (1/7. 45 x 105 cubic meters) . The fish schools appeared to be 5 to 10 meters thick, 10 to 100 meters in diameter, and on centers 100 to 200 meters apart. Density within schools was estimated at 10 to 15 fish per cubic meter.Supported in part by contracts Nonr-3484(00) and Nonr-4029(00) and by NSF grant GB-4431

    Results on Plasma Focusing of High Energy Density Electron and Positron Beams

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    We present results from the SLAC E-150 experiment on plasma focusing of high energy density electron and, for the first time, positron beams. We also discuss measurements on plasma lens-induced synchrotron radiation, longitudinal dynamics of plasma focusing, and laser- and beam-plasma interactions.Comment: LINAC 2000 paper No. THC13, Monterey, CA. Aug.21-25,2000, 3 pages, 2 figure

    High-dose etoposide with granulocyte colony-stimulating factor for mobilization of peripheral blood progenitor cells: efficacy and toxicity at three dose levels.

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    High-dose etoposide (2.0-2.4 g m(-2)) with granulocyte colony-stimulating factor (G-CSF) is an effective strategy to mobilize peripheral blood progenitor cells (PBPCs), although in some patients this is associated with significant toxicity. Sixty-three patients with malignancy were enrolled into this non-randomized sequential study. The majority (55/63, 87%) had received at least two prior regimens of chemotherapy, and seven patients had previously failed to mobilize following high-dose cyclophosphamide with G-CSF. Consecutive patient groups received etoposide at three dose levels [2.0 g m(-2) (n = 22), 1.8 g m(-2) (n = 20) and 1.6 g m(-2) (n = 21)] followed by daily G-CSF. Subsequent leukaphereses were assayed for CD34+ cell content, with a target total collection of 2.0 x 10(6) CD34+ cells kg(-1). Toxicity was assessed by the development of significant mucositis, the requirement for parenteral antibiotics or blood component support and rehospitalization incidence. Ten patients (16%) had less than the minimum target yield collected. Median collections in the three groups were 4.7 (2 g m(-2)), 5.7 (1.8 g m(-2)) and 6.5 (1.6 g m(-2)) x 10(6) CD34+ cells kg(-1). Five of the seven patients who had previously failed cyclophosphamide mobilization achieved more than the target yield. Rehospitalization incidence was significantly lower in patients receiving 1.6 g m(-2) etoposide than in those receiving 2.0 g m(-2) (P = 0.03). These data suggest that high-dose etoposide with G-CSF is an efficient mobilization regimen in the majority of heavily pretreated patients, including those who have previously failed on high-dose cyclophosphamide with G-CSF. An etoposide dose of 1.6 g m(-2) appears to be as effective as higher doses but less toxic

    Metal alloys, matrix inclusions and manufacturing techniques of Moinhos de Golas collection (North Portugal): a study by micro-EDXRF, SEM–EDS, optical microscopy and X-ray radiography

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    "Article:820"A collection of 35 metallic artefacts comprising various typologies, some of which can be attributed to the Bronze Age and others to later periods, were studied to provide detailed information on elemental composition, manufacturing techniques and preservation state. Elemental analysis by micro-EDXRF and SEM–EDS was performed to investigate the use of different alloys and to study the presence of microstructural heterogeneities, as inclusions. X-ray radiography, optical microscopy and SEM–EDS were used to investigate manufacturing techniques and degradation features. Results showed that most of the artefacts were produced in a binary bronze alloy (Cu–Sn) with 10–15 wt% Sn and a low concentration of impurities. Other artefacts were produced in copper or in brass, the latest with varying contents of Zn, Sn and Pb. A variety of inclusions in the metal matrices were also found, some related to specific types of alloys, as (Cu–Ni)S2 in coppers, or ZnS in brasses. Microstructural observations revealed that the majority of the artefacts were subjected to cycles of thermomechanical processing after casting, being evident that among some artefacts different parts were subjected to distinct treatments. The radiographic images revealed structural heterogeneities related to local corrosion processes and fissures that seem to have developed in wear-tension zones, as in the handle of some daggers. Radiographic images were also useful to detect the use of different materials in one particular brass artefact, revealing the presence of a possible Cu–Sn solder.This work was funded by FEDER funds through the COMPETE 2020 Programme and National Funds through FCT— Fundação para a Ciência e a Tecnologia under the project UID/CTM/ 50025/2013 to CENIMAT/I3N. C2 TN/IST authors gratefully acknowledge the FCT support through the UID/Multi/04349/2013 project. EF acknowledges FCT for the grant SFRH/BPD/97360/2013. JF acknowledge FCT for the grant SFRH/BD/65143/2009. Part of this project has been done in the framework of the FCT project ENARDAS (PTDC/HISARQ/112983/2009).info:eu-repo/semantics/publishedVersio
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