429 research outputs found
High-performance -type organic field-effect transistors with ionic liquid gates
High-performance -type organic field-effect transistors were developed
with ionic-liquid gates and N,N-bis(n-alkyl)-(1,7 and
1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide)s single-crystals. Transport
measurements show that these devices reproducibly operate in ambient atmosphere
with negligible gate threshold voltage and mobility values as high as 5.0
cm/Vs. These mobility values are essentially identical to those measured in
the same devices without the ionic liquid, using vacuum or air as the gate
dielectric. Our results indicate that the ionic-liquid and -type organic
semiconductor interfaces are suitable to realize high-quality -type organic
transistors operating at small gate voltage, without sacrificing electron
mobility
Shear strength of an unsaturated silty sand
This paper presents a series of direct shear tests performed on a silty sand at three different gravimetric water contents. The soil was sampled from test pits south of Ruedlingen in North East Switzerland, where a landslide triggering experiment was carried out on a 37°-40° steep forested slope through infiltration of extreme artificial rainfall. The aim of this work was mainly to establish a correlation between the degree of saturation and slope stability. Direct shear tests were performed on reconstituted samples with a direct shear apparatus under undrained conditions for the water phase. Three of the samples were saturated after the shear phase in order to analyse the effect of wetting on shear strength. The results were interpreted with the assistance of a soil water retention curve (WRC) and an analytical slope stability analysis was performed to apply the laboratory results to the field experimen
A KNOWLEDGE BASED APPROACH FOR RESOURCE MANAGEMENT
This paper discusses the applicability of a knowledge based system to resource management in the context of information centers. The Information Center Expert (ICE) system has been developed in the MIS Department of the University of Arizona to support the consultation process of information center personnel. The system determines the (software) resource requirements of the end-users and makes appropriate recommendations. ICE further aids the management of the IC software resources by keeping track of user consultations and the recommendations made. Issues of knowledge requirements, acquisition, representation and implementation of ICE are discussed. ICE is currently being tested at IBM/Endicott (New York), IBM/Tucson (Arizona) and the Center for the Management of Information at the University of Arizona. Preliminary feedback from users has confirmed the applicability of the knowledge based approach to resource management. The implications of this approach for future research are discussed
Superconductivity enhanced conductance fluctuations in few layer graphene nanoribbons
We investigate the mesoscopic disorder induced rms conductance variance
in a few layer graphene nanoribbon (FGNR) contacted by two
superconducting (S) Ti/Al contacts. By sweeping the back-gate voltage, we
observe pronounced conductance fluctuations superimposed on a linear background
of the two terminal conductance G. The linear gate-voltage induced response can
be modeled by a set of inter-layer and intra-layer capacitances.
depends on temperature T and source-drain voltage .
increases with decreasing T and . When lowering , a
pronounced cross-over at a voltage corresponding to the superconducting energy
gap is observed. For |V_{sd}|\ltequiv \Delta the fluctuations are
markedly enhanced. Expressed in the conductance variance of one
graphene-superconducutor (G-S) interface, values of 0.58 e^2/h are obtained at
the base temperature of 230 mK. The conductance variance in the sub-gap region
are larger by up to a factor of 1.4-1.8 compared to the normal state. The
observed strong enhancement is due to phase coherent charge transfer caused by
Andreev reflection at the nanoribbon-superconductor interface.Comment: 15 pages, 5 figure
BPMN task instance streaming for efficient micro-task crowdsourcing processes
The Business Process Model and Notation (BPMN) is a standard for modeling and executing business processes with human or machine tasks. The semantics of tasks is usually discrete: a task has exactly one start event and one end event; for multi-instance tasks, all instances must complete before an end event is emitted. We propose a new task type and streaming connector for crowdsourcing able to run hundreds or thousands of micro-task instances in parallel. The two constructs provide for task streaming semantics that is new to BPMN, enable the modeling and efficient enactment of complex crowdsourcing scenarios, and are applicable also beyond the special case of crowdsourcing. We implement the necessary design and runtime support on top of Crowd- Flower, demonstrate the viability of the approach via a case study, and report on a set of runtime performance experiments
Synthesizing a spin-dependent force for optical, metastable, and ground state trapped-ion qubits
A single bichromatic field near-resonant to a qubit transition is typically
used for or M{\o}lmer-S{\o}rensen type
interactions in trapped ion systems. Using this field configuration, we present
a novel scheme to synthesize a spin-dependent force instead;
this basis change merely requires adjusting the beat-note frequency of the
bichromatic field. We implement this scheme with a laser near-resonant to a
quadrupole transition in Sr. We characterise its robustness to
optical phase and qubit frequency offsets and demonstrate its versatility by
entangling optical, metastable, and ground state qubits.Comment: O. B\u{a}z\u{a}van and S. Saner contributed equally to this wor
Breaking the entangling gate speed limit for trapped-ion qubits using a phase-stable standing wave
All laser-driven entangling operations for trapped-ion qubits have hitherto
been performed without control of the optical phase of the light field, which
precludes independent tuning of the carrier and motional coupling. By placing
Sr ions in a nm standing wave, whose relative position
is controlled to , we suppress the carrier coupling by a
factor of , while coherently enhancing the spin-motion coupling. We
experimentally demonstrate that the off-resonant carrier coupling imposes a
speed limit for conventional traveling-wave M{\o}lmer-S{\o}rensen gates; we use
the standing wave to surpass this limit and achieve a gate duration of $15\
\mu$s, restricted by the available laser power.Comment: S. Saner and O. B\u{a}z\u{a}van contributed equally to this wor
Cardiovascular mortality and exposure to extremely low frequency magnetic fields: a cohort study of Swiss railway workers
<p>Abstract</p> <p>Background</p> <p>Exposure to intermittent magnetic fields of 16 Hz has been shown to reduce heart rate variability, and decreased heart rate variability predicts cardiovascular mortality. We examined mortality from cardiovascular causes in railway workers exposed to varying degrees to intermittent 16.7 Hz magnetic fields.</p> <p>Methods</p> <p>We studied a cohort of 20,141 Swiss railway employees between 1972 and 2002, including highly exposed train drivers (median lifetime exposure 120.5 μT-years), and less or little exposed shunting yard engineers (42.1 μT-years), train attendants (13.3 μT-years) and station masters (5.7 μT-years). During 464,129 person-years of follow up, 5,413 deaths were recorded and 3,594 deaths were attributed to cardio-vascular diseases. We analyzed data using Cox proportional hazards models.</p> <p>Results</p> <p>For all cardiovascular mortality the hazard ratio compared to station masters was 0.99 (95%CI: 0.91, 1.08) in train drivers, 1.13 (95%CI: 0.98, 1.30) in shunting yard engineers, and 1.09 (95%CI: 1.00, 1.19) in train attendants.Corresponding hazard ratios for arrhythmia related deaths were 1.04 (95%CI: 0.68, 1.59), 0.58 (95%CI: 0.24, 1.37) and 1.30 (95%CI: 0.87, 1.93) and for acute myocardial infarction 1.00 (95%CI: 0.73, 1.36), 1.56 (95%CI: 1.04, 2.32), and 1.14 (95%CI: 0.85, 1.53). The hazard ratio for arrhythmia related deaths per 100 μT-years of cumulative exposure was 0.94 (95%CI: 0.71, 1.24) and 0.91 (95%CI: 0.75, 1.11) for acute myocardial infarction.</p> <p>Conclusion</p> <p>This study provides evidence against an association between long-term occupational exposure to intermittent 16.7 Hz magnetic fields and cardiovascular mortality.</p
Mapping of Dietary Interventions Beneficial in the Prevention of Secondary Health Conditions in Spinal Cord Injured Population: A Systematic Review.
OBJECTIVES
Individuals with spinal cord injury are at risk of secondary health conditions (SHC) that develop as a consequence of autonomic dysfunction, prolonged oxidative stress and inflammation, and physical inactivity coupled with inadequate energy and nutritional intake. SHC can be debilitating and even life-threatening, and its prevention remains one of the major challenges in the continuum of medical care of aging SCI population. An unhealthy diet is a major driver of inflammation, oxidative stress, and unfavourable metabolic status and may be a practical preventive target to tackle increased SHC risk post-injury.
AIMS
To provide a catalogue of dietary interventions beneficial in prevention of SHC among individuals with SCI by conducting a systematic review of the literature on dietary interventions and dietary supplementation in promoting health and well-being after the injury. In addition, we aimed to provide a summary of observational studies exploring the association between habitual diet (macro- and micronutrients intake and dietary patterns) and health patterns following the injury.
METHOD
This review was registered at PROSPERO (University of York) with registration number CRD42022373773. Four medical databases (EMBASE.com, MEDLINE [Ovid], Cochrane CENTRAL, and Web of Science Core Collection) and Google Scholar were searched from inception until 11th July 2022. Studies were included if they were clinical trials or observational studies conducted in adult individuals with SCI and provided information of interest. Based on strength of the study design and risk of bias assessment (using the NIH tool), we classified studies from Level 1 (most reliable studies) to Level 4 (least reliable studies).
RESULTS
Of 12,313 unique citations, 47 articles (based on 43 original studies) comprising 32 interventional (22 RCTs, 3 NRCT, and 7 pre-post studies) and 11 observational studies (2 cohort studies, 2 case-control, 1 post-intervention follow-up study, and 6 cross-sectional studies) were included in the present systematic review. Twenty studies (46.5%) were classified as Level 1 or 2, indicating high/moderate methodological quality. Based on those studies, dietary strategies including high protein diet, intermittent fasting, balanced diet in combination with physical conditioning and electrical stimulation, and dietary supplementation including alpha-lipoic acid, creatine, vitamin D, and cranberry-derived supplements and probiotics were mapped as the most promising in prevention of SHC among individuals with SCI.
CONCLUSIONS
To develop timely and effective preventive strategies targeting major SHC (e.g., cardiometabolic diseases, urinary tract infections) in SCI, further research is warranted to confirm the effectiveness of dietary strategies/interventions identified through the current systematic review of the literature
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