172 research outputs found

    Few electron double quantum dot in an isotopically purified 28^{28}Si quantum well

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    We present a few electron double quantum dot (QD) device defined in an isotopically purified 28^{28}Si quantum well (QW). An electron mobility of 5.5104cm2(Vs)15.5 \cdot 10^4 cm^2(Vs)^{-1} is observed in the QW which is the highest mobility ever reported for a 2D electron system in 28^{28}Si. The residual concentration of 29^{29}Si nuclei in the 28^{28}Si QW is lower than 103ppm10^{3} ppm, at the verge where the hyperfine interaction is theoretically no longer expected to dominantly limit the T2T_{2} spin dephasing time. We also demonstrate a complete suppression of hysteretic gate behavior and charge noise using a negatively biased global top gate.Comment: 4 pages, 3 figure

    Comorbid Depression Among Untreated Illicit Opiate Users : Results From a Multisite Canadian Study

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    This study aimed to describe patterns of major depression (MDD) in a cohort of untreated illicit opiate users recruited from 5 Canadian urban centres, identify sociodemographic characteristics of opiate users that predict MDD, and determine whether opiate users suffering from depression exhibit different drug use patterns than do participants without depression. Baseline data were collected from 679 untreated opiate users in Vancouver, Edmonton, Toronto, Montreal, and Quebec City. Using the Composite International Diagnostic Interview Short Form for Major Depression, we assessed sociodemographics, drug use, health status, health service use, and depression. We examined depression rates across study sites; logistic regression analyses predicted MDD from demographic information and city. Chi-square analyses were used to compare injection drug use and cocaine or crack use among participants with and without depression. Almost one-half (49.3%) of the sample met the cut-off score for MDD. Being female, white, and living outside Vancouver independently predicted MDD. Opiate users suffering from depression were more likely than users without depression to share injection equipment and paraphernalia and were also more likely to use cocaine (Ps < 0.05). Comorbid depression is common among untreated opiate users across Canada; targeted interventions are needed for this population

    Web-Based Health Services in Forensic Psychiatry: A Review of the Use of the Internet in the Treatment of Child Sexual Abusers and Child Sexual Exploitation Material Offenders

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    In recent years, web-based health services for a variety of mental disorders have been developed and evaluated. Evidence suggests that guided internet-based therapy can be as effective as conventional face-to-face therapy. In forensic psychiatric practice, few web-based treatments have been implemented up to now. However, to our knowledge, there do not yet exist guided internet-based treatments for child sexual abusers and child sexual exploitation material offenders. This review aims at examining under what conditions patients are most likely to benefit from internet-based treatments. In addition, some computer-based health services in forensic psychiatry will be summarized and their potentials and weaknesses will be discussed. Subsequently, the review focuses on the implications for the development of online treatments for child sexual abusers as well as on a variety of ethical and legal issues that practitioners may encounter during the development, evaluation and delivery of online health services. The review will conclude with proposed quality standards for the development and implementation of web-based interventions for child sexual abusers and child sexual exploitation material offenders. By virtue of the low number of psychotherapists offering therapy to this clientele as well as individual barriers to seeking treatment such as fear of stigmatization, feelings of shame, long access routes, or limited mobility due to physical handicaps, the development of mental eHealth services in this sector could close an important healthcare gap. By increasing the density of supply, more child sexual abusers and child sexual exploitation material offenders would have the chance to engage in treatment and, ultimately, more incidents of sexual assault against minors could be prevented

    Acute exposure to nocturnal train noise induces endothelial dysfunction and pro-thromboinflammatory changes of the plasma proteome in healthy subjects

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    Nocturnal train noise exposure has been associated with hypertension and myocardial infarction. It remains unclear whether acute nighttime train exposure may induce subclinical atherosclerosis, such as endothelial dysfunction and other functional and/or biochemical changes. Thus, we aimed to expose healthy subjects to nocturnal train noise and to assess endothelial function, changes in plasma protein levels and clinical parameters. In a randomized crossover study, we exposed 70 healthy volunteers to either background or two different simulated train noise scenarios in their homes during three nights. After each night, participants visited the study center for measurement of vascular function and assessment of other biomedical and biochemical parameters. The three nighttime noise scenarios were exposure to either background noise (control), 30 or 60 train noise events (Noise30 or Noise60), with average sound pressure levels of 33, 52 and 54 dB(A), respectively. Flow-mediated dilation (FMD) of the brachial artery was 11.23 ± 4.68% for control, compared to 8.71 ± 3.83% for Noise30 and 8.47 ± 3.73% for Noise60 (p < 0.001 vs. control). Sleep quality was impaired after both Noise30 and Noise60 nights (p < 0.001 vs. control). Targeted proteomic analysis showed substantial changes of plasma proteins after the Noise60 night, mainly centered on redox, pro-thrombotic and proinflammatory pathways. Exposure to simulated nocturnal train noise impaired endothelial function. The proteomic changes point toward a proinflammatory and pro-thrombotic phenotype in response to nocturnal train noise and provide a molecular basis to explain the increased cardiovascular risk observed in epidemiological noise studies

    Základy půdní úrodnosti

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    Zvyšování půdní úrodnosti bylo pro průkopníky ekologického zemědělství základem veškerého jejich úsilí. Přesto zachování úrodné půdy mnohdy nebyla věnována dostatečná pozornost. Ekologické zemědělství je však na přirozené půdní úrodnosti závislé. Oslabená a poškozená půda nám nemůže poskytnout to, co od ní očekáváme. Udržet úrodnost půdy vyžaduje velkou péči. Předkládaná brožura ukazuje půdní úrodnost z různých úhlů pohledu. Naším záměrem však nebylo vytvořit obecně platný „návod k použití“. Informace mají být mnohem spíše podnětem k tomu, aby se o vztahu člověka k půdě smýšlelo jinak a aby se tento vztah utvářel ve prospěch budoucnosti

    In situ spatiotemporal measurements of the detailed azimuthal substructure of the substorm current wedge

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    The substorm current wedge (SCW) is a fundamental component of geomagnetic substorms. Models tend to describe the SCW as a simple line current flowing into the ionosphere toward dawn and out of the ionosphere toward dusk, linked by a westward electrojet. We use multispacecraft observations from perigee passes of the Cluster 1 and 4 spacecraft during a substorm on 15 January 2010, in conjunction with ground-based observations, to examine the spatial structuring and temporal variability of the SCW. At this time, the spacecraft traveled east-west azimuthally above the auroral region. We show that the SCW has significant azimuthal substructure on scales of 100km at altitudes of 4000-7000km. We identify 26 individual current sheets in the Cluster 4 data and 34 individual current sheets in the Cluster 1 data, with Cluster 1 passing through the SCW 120-240s after Cluster 4 at 1300-2000km higher altitude. Both spacecraft observed large-scale regions of net upward and downward field-aligned current, consistent with the large-scale characteristics of the SCW, although sheets of oppositely directed currents were observed within both regions. We show that the majority of these current sheets were closely aligned to a north-south direction, in contrast to the expected east-west orientation of the preonset aurora. Comparing our results with observations of the field-aligned current associated with bursty bulk flows (BBFs), we conclude that significant questions remain for the explanation of SCW structuring by BBF-driven wedgelets. Our results therefore represent constraints on future modeling and theoretical frameworks on the generation of theSCW. Key Points The substorm current wedge (SCW) has significant azimuthal structure Current sheets within the SCW are north-south aligned The substructure of the SCW raises questions for the proposed wedgelet scenari
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