1,636 research outputs found
Swimming using surface acoustic waves
Microactuation of free standing objects in fluids is currently dominated by the rotary propeller, giving rise to a range of potential applications in the military, aeronautic and biomedical fields. Previously, surface acoustic waves (SAWs) have been shown to be of increasing interest in the field of microfluidics, where the refraction of a SAW into a drop of fluid creates a convective flow, a phenomenon generally known as SAW streaming. We now show how SAWs, generated at microelectronic devices, can be used as an efficient method of propulsion actuated by localised fluid streaming. The direction of the force arising from such streaming is optimal when the devices are maintained at the Rayleigh angle. The technique provides propulsion without any moving parts, and, due to the inherent design of the SAW transducer, enables simple control of the direction of travel
Questioning the Legitimacy of the Expedited Removal Process – The Tall Task of Protecting the Constitutional Rights of One of America’s Most Marginalized Groups
This Note explores the origin and development of 8 U.S.C. § 1225—a heavily debated facet of the United States’ immigration law. Section 1225, colloquially referred to as the “expedited removal process,” has been interpreted to permit low-level immigration officers to summarily remove certain “arriving” noncitizens from the United States without affording them the procedural due process protections guaranteed under the Fifth Amendment of the United States Constitution to all individuals present in the United States. This Note posits that the current interpretation of § 1225, particularly the interpretation of “is arriving,” and application of the expedited removal process is inconsistent with well-established canons of statutory interpretation—particularly the plain meaning canon, the no superfluous words canon, and the constitutional presumption canon. This Note then puts forth an interpretation that is consistent with these central canons of interpretation. Finally, this Note argues that due to the Fifth Amendment’s broad applicability, the refusal to afford procedural safeguards prior to the denial of life, liberty, and property via the expedited removal process constitutes a wholly unconstitutional due process violation and that even the expansive entry fiction doctrine is not enough to save this unconstitutional removal process. Thus, the expedited removal process, as it is currently employed, must be abandoned and § 1225 must be either amended or repealed
Extremely Low Loss Phonon-Trapping Cryogenic Acoustic Cavities for Future Physical Experiments
Low loss Bulk Acoustic Wave devices are considered from the point of view of
the solid state approach as phonon-confining cavities. We demonstrate effective
design of such acoustic cavities with phonon-trapping techniques exhibiting
extremely high quality factors for trapped longitudinally-polarized phonons of
various wavelengths. Quality factors of observed modes exceed 1 billion, with a
maximum -factor of 8 billion and product of at
liquid helium temperatures. Such high sensitivities allow analysis of intrinsic
material losses in resonant phonon systems. Various mechanisms of phonon losses
are discussed and estimated
Transients Analysis Of Distributed Systems
An isomorphic relation exists between the transient response of systems whose transfer functions are of the form H(s)=B and the transient response of systems whose transfer functions are of the form [formula omitted]. Several interesting conclusions are drawn from this relationship concerning the transient response of distributed systems. Copyright © 1969 by The Insitute of Electrical and Electronics Engineers Inc
PCR-RFLP analysis of Vitis, Ampelopsis and Parthenocissus and its application to the identification of rootstocks
Methodologies based on the analysis of DNA polymorphism were recently described to identify and study grapevine rootstocks and cultivars. We report here rapid RFLP analysis of 17 Vitis, 3 Ampelopsis and 2 Parthenocissus DNAs amplified by PCR with primers based on sequences from previously defined polymorphic DNA fragments of V. vinifera cv. Chardonnay. These primers can be used as a tool for phylogenetic studies in the genus Vitis and more generally within the Vitaceae family. The DNAs of 22 rootstocks could be identified by PCR using 4 pairs of Chardonnay-derived primers combined with RFLP analysis. However, it was impossible to discriminate between 9 clones of the rootstock 3309 C. This technique is rapid and well reproducible
SU(3) Breaking in Hyperon Beta Decays: a Prediction for Xi^0 -> Sigma^+ e nu-bar
On the basis of a previous analysis of hyperon semi-leptonic decay data, a
prediction is presented for g_1/f_1 in the Xi^0 -> Sigma^+ e nu-bar beta-decay.
The analysis takes into account SU(3) breaking in this sector via the inclusion
of mass-driven corrections. A rather precise measurement of the above channel
by the KTeV experiment at Fermilab will shortly be available. Since the
dependence on the SU(3) parameters, F and D, is identical to that of the
neutron beta-decay, such a measurement will provide a rather stringent test of
SU(3) and the models used to describe its violation in these decays. The
prediction given here for the above decay is g_1/f_1=1.17, which leads to a
rate of 0.80 x 10^6 s^-1 and thus a branching fraction of 2.3 x 10^-4.Comment: LaTeX, 7 pages, uses acromake, cite and topcapt packages.
Non-printing extended ascii characters replaced plus minor correction
Identification of sixteen grapevine rootstocks by RFLP and RFLP analysis of nuclear DNA extracted from the wood
Sixteen rootstocks of the Vitis genus have been identified by the RFLP analysis methodology with the restriction enzyme HinfI. Uniques or moderately repeated DNA sequences of the nuclear genome of the Chardonnay V. vinifera variety were used as probes. RFLP analysis of 5 clones of SO 4 (V. berlandieri x V. riparia) and of 3 clones of 41 B Mgt (V. berlandieri x V. vinifera) with 4 probes and HinfI did not lead to any polymorphism. This is not surprising because of the vegetative origin of the clones. A simple method of nuclear DNA extraction of wood is described for the grapevine. We propose now the RFLP analysis methodology to complement or to replace in certain cases the ampelographical methods of identification of the rootstocks. The extension of this application to the V. vinifera varieties is considered.Identification de 16 porte-greffes de vigne par analyse RFLP, et analyse RFLP d'ADN nucléaire extrait à partir du boisNous avons identifié 16 porte-greffes du genre Vitis par la méthodologie d'analyse du polymorphisme de longueur des fragments de restriction (RFLP) de l'ADN avec l'enzyme de restriction HinfI. Pour cela, nous avons utilisé comme sondes des fragments d'ADN uniques ou peu répétés du génome de la variete Chardonnay de Vitis vinifera. L'analyse RFLP de cinq clones de SO 4 (V. berlandieri x V. riparia) et de trois clones de 41 B Mgt (V. berlandieri x V. vinifera) avec quatre sondes RFLP et l'enzyme HinfI n'a pas permis de différencier les clones d'un même hybride, dont les genomes sont extrêmement proches puisqu'ils sont obtenus de façon végétative. Nous présentons aussi une méthode simple d'extraction d'ADN nucléaire à partir du bois de vigne. Les analyses RFLP de cet ADN ont donné des résultats identiques à ceux obtenus avec l'ADN des feuilles. Nous sommes maintenant en mesure de proposer que la méthodologie d'analyse RFLP complète ou remplace dans certains cas les méthodes ampélographiques d'identification des portegreffes du genre Vitis. L'élargissement de cette application est envisagé pour les varietes de Vitis vinifera
Collaboration in a multi-user game: impacts of an awareness tool on mutual modeling
This paper presents an experimental research that focuses on collaboration in a multi-player game. The aim of the project is to study the cognitive impacts of awareness tools, i.e., artifacts that allow users of a collaborative system to be aware of what is going on in the joint virtual environment. The focus is on finding an effect on performance as well as on the representation an individual builds of what his partner knows, plans and intends to do (i.e., mutual modeling). We find that using awareness tools has a significant effect by improving task performance. However, the players who were provided with this tool did not show any improvement of their mutual modeling. Further analysis on contrasted groups revealed that there was an effect of the awareness tool on mutual modeling for players who spent a large amount of time using the too
Substance use and its association with mental health among Swiss medical students: A cross-sectional study.
Studies on mental health and substance use among medical students indicated worrying prevalence but have been mainly descriptive.
To evaluate the prevalence of substance use in a sample of medical students and investigate whether mental health variables have an influence on substance use.
The data were collected as part of the first wave of the ETMED-L, an ongoing longitudinal open cohort study surveying medical students at the University of Lausanne (Switzerland). N = 886 students were included and completed an online survey including measures of mental health (depression, suicidal ideation, anxiety, stress, and burnout) and use of and risk related with several substances (tobacco, alcohol, cannabis, cocaine, stimulants, sedatives, hallucinogens, opioids, nonmedical prescription drugs, and neuroenhancement drugs). We evaluated the prevalence of use of each substance and then tested the association between mental health and substance use in an Exploratory Structural Equation Modeling framework.
Statistical indices indicated a four-factor solution for mental health and a three-factor solution for substance use. A factor comprising risk level for alcohol, tobacco, and cannabis use - which were the most prevalent substances - was significantly associated with a burnout factor and a factor related to financial situation and side job stress. There was a significant association between a factor comprising depression, anxiety, and suicidal ideation and a factor related to the use of sedatives, nonmedical prescription drugs and neuroenhancement drugs. Although their use was less prevalent, a factor comprising the risk level of stimulants and cocaine use was significantly but more mildly related to the burnout factor. A factor comprising stress related to studies and work/life balance as well as emotional exhaustion was not related to substance use factors.
In this sample of medical students, the prevalence of substance use was substantial and poorer mental health status was related with higher substance use risk levels
The Permian-Triassic boundary and Early Triassic sedimentation in Western European basins: an overview
At the scale of the peri-Tethyan basins of western Europe, the “Buntsandstein” continental lithostratigraphic units are frequently attributed to the “Permian-Triassic” because, in most cases, the lack of any “Scythian” (i.e. Early Triassic) biochronological evidence makes it very difficult to attribute the basal beds of the cycle to the Permian or to the Triassic. A careful recognition of unconformities and sedimentary indications of clearly arid climate provide powerful tools for correlation within non-marine successions that are devoid of any biostratigraphic markers, at least on the scale of the West European Plate. From a review of the “Buntsandstein” series of several basins we can characterize the Permian-Triassic boundary and the beginning of Triassic sedimentation at the scale of Western Europe. We clearly show that, except for the Central Germanic Basin, an unconformity can be observed between the Permian and the Triassic. Apart from the Germanic Basin, there is a total lack of typically “Scythian” fossils in the rest of West European basins, and the oldest biochronological markers yielded by these units are palynomorphs allowing to assign an Anisian age generally to the upper part of the “Buntsandstein”, but also its lowermost in a few cases. In the peri-Tethyan basins of western Europe, the Permian-Triassic boundary corresponds to an unconformity overlain by conglomerates containing ventifacts (followed by fluvial sandstones, sometimes rich in paleosols and sometimes totally devoid), which are attributed mainly to the lower Olenekian, i.e. Smithian. Alternatively, the succession passes up directly into fluvial sandstones containing the first paleosols, and then plant debris and palynomorphs attributed to the Anisian. In this way, the lack of typically Early Triassic fossils in most of the peri-Tethyan basins, at the scale of the west European Plate, can be explained by a true stratigraphic hiatus in the earliest Triassic (i.e. Induan) and by arid conditions unfavourable for the development of flora and fauna and their preservation during the Olenekian.En las cuencas peritéthicas de Europa occidental, la unidad litoestratigráfi ca continental “Buntsandstein” es frecuentemente atribuida al “Pérmico-Triásico”, porque, en la mayoría de los casos, la falta de elementos biocronológicos “scythienses” complica la atribución de los niveles basales al Pérmico o al Triásico. Un cuidadoso examen de las discordancias, y el uso de indicadores sedimentarios de climas claramente áridos constituyen herramientas fundamentales para la correlación de estas unidades no marinas, desprovistas de cualquier marcador bioestratigráfi co, al menos en el Oeste de la Placa Europea. La revisión de las series “Buntsandstein” de varias cuencas nos ha permitido caracterizar el límite Pérmico-Triásico y el comienzo de la sedimentación durante el Triásico inferior en el oeste de Europa, demostrando claramente que, excepto en la Cuenca Germánica Central, se puede observar una discordancia entre las series pérmicas y triásicas. Excepto en esta Cuenca Germánica, existe una falta total de fósiles típicamente “scythienses”, y los elementos bioestratigráfi cos más antiguos encontrados son conjuntos de palinomorfos que permiten asignar a los niveles superiores de las series “Buntsandstein” una edad Anisiense, en algunos cortes los niveles inferiores. En las cuencas peritéthicas de Europa occidental, el límite Pérmico-Triásico se corresponde con una discordancia que se recubre por conglomerados con ventifactos (seguidos por areniscas fl uviales, a veces ricas en paleosuelos y a veces totalmente desprovistas de ellos), atribuidos principalmente al Olenekiense inferior (Smithiense), o directamente areniscas fluviales donde aparecen los primeros paleosuelos, así como restos de plantas y palinomorfos, atribuidos al Anisiense. De esta forma en el Oeste de la Placa Europea, la falta de fósiles característicos del Triásico Inferior, en la mayoría de las cuencas perithéticas, puede explicarse por un importante hiato estratigráfi co durante el Triásico Inferior (Induense) y por unas condiciones áridas, desfavorables para la vida y la preservación de fósiles durante el Olenekiense
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