211 research outputs found
Bed scour by debris flows: experimental investigation of effects of debris-flow composition
Debris flows can grow greatly in size by entrainment of bed material, enhancing their runout and hazardous impact. Here, we experimentally investigate the effects of debris-flow composition on the amount and spatial patterns of bed scour and erosion downstream of a fixed to erodible bed transition. The experimental debris flows were observed to entrain bed particles both grain by grain and en masse, and the majority of entrainment was observed to occur during passage of the flow front. The spatial bed scour patterns are highly variable, but large-scale patterns are largely similar over 22.5–35° channel slopes for debris flows of similar composition. Scour depth is generally largest slightly downstream of the fixed to erodible bed transition, except for clay-rich debris flows, which cause a relatively uniform scour pattern. The spatial variability in the scour depth decreases with increasing water, gravel (= grain size) and clay fraction. Basal scour depth increases with channel slope, flow velocity, flow depth, discharge and shear stress in our experiments, whereas there is no correlation with grain collisional stress. The strongest correlation is between basal scour and shear stress and discharge. There are substantial differences in the scour caused by different types of debris flows. In general, mean and maximum scour depths become larger with increasing water fraction and grain size, and decrease with increasing clay content. However, the erodibility of coarse-grained experimental debris flows (gravel fraction = 0.64) is similar on a wide range of channel slopes, flow depths, flow velocities, discharges and shear stresses. This probably relates to the relatively large influence of grain-collisional stress to the total bed stress in these flows (30–50%). The relative effect of grain-collisional stress is low in the other experimental debris flows (<5%), causing erosion to be largely controlled by basal shear stres
BAMBOO for Refugees—A culturally sensitive positive psychology intervention:A protocol for a pilot Randomized Controlled Trial
This protocol investigates the efficacy of a mental health and psychosocial support (MHPSS) program named BAMBOO. The goal of this program is to increase resilience and mental well-being among refugees. In recent years, there has been an increasing number of refugees fleeing to Europe and applying for permanent residence. In the Netherlands, a wide variety of programs that focus on increasing mental well-being among refugees is available. BAMBOO is a strengths-based intervention, which consists of five weekly two-hour group-based sessions. It is based on the theoretical framework of positive psychology and adapted according to the guidelines for the implementation of culturally sensitive cognitive behavioral therapy among refugees. The program does not focus on the treatment of trauma, mental disorders, or underlying problems, but aims to increase factors such as personal strengths, positive emotions, positive relations, and self-esteem. The first version of the program (BAMBOO 1.0) has been conducted at over 50 asylum centers in the Netherlands since January 2020. In the time period from September 2020 to September 2022, qualitative and quantitative data were collected among BAMBOO trainers and participants and the program was adapted, leading to a revised version (BAMBOO 2.0). A single-blinded parallel pilot randomized controlled trial, with an intervention group and awaiting list control group, with 34 participants per group will be used to test the program’s efficacy. Outcomes include resilience, satisfaction with life, positive and negative affect, and self-esteem. The study will be conducted among adult Arabic speaking refugees, residing at an asylum center in the Netherlands and/ or in a Dutch municipality, Baseline, post-intervention, and five-week follow-up assessments will be conducted. This paper describes the protocol for the evaluation of a novel and culturally adapted program. The study will shed light on the efficacy of a culturally sensitive strengths-based intervention as a preventive approach to increase refugee well-bein
BAMBOO for Refugees—A culturally sensitive positive psychology intervention:A protocol for a pilot Randomized Controlled Trial
This protocol investigates the efficacy of a mental health and psychosocial support (MHPSS) program named BAMBOO. The goal of this program is to increase resilience and mental well-being among refugees. In recent years, there has been an increasing number of refugees fleeing to Europe and applying for permanent residence. In the Netherlands, a wide variety of programs that focus on increasing mental well-being among refugees is available. BAMBOO is a strengths-based intervention, which consists of five weekly two-hour group-based sessions. It is based on the theoretical framework of positive psychology and adapted according to the guidelines for the implementation of culturally sensitive cognitive behavioral therapy among refugees. The program does not focus on the treatment of trauma, mental disorders, or underlying problems, but aims to increase factors such as personal strengths, positive emotions, positive relations, and self-esteem. The first version of the program (BAMBOO 1.0) has been conducted at over 50 asylum centers in the Netherlands since January 2020. In the time period from September 2020 to September 2022, qualitative and quantitative data were collected among BAMBOO trainers and participants and the program was adapted, leading to a revised version (BAMBOO 2.0). A single-blinded parallel pilot randomized controlled trial, with an intervention group and awaiting list control group, with 34 participants per group will be used to test the program’s efficacy. Outcomes include resilience, satisfaction with life, positive and negative affect, and self-esteem. The study will be conducted among adult Arabic speaking refugees, residing at an asylum center in the Netherlands and/ or in a Dutch municipality, Baseline, post-intervention, and five-week follow-up assessments will be conducted. This paper describes the protocol for the evaluation of a novel and culturally adapted program. The study will shed light on the efficacy of a culturally sensitive strengths-based intervention as a preventive approach to increase refugee well-bein
Front versus rear side light-ion acceleration from high-intensity laser–solid interactions
The source of ions accelerated from high-intensity laser interactions with thin foil targets is investigated by coating a deuterated plastic layer either on the front, rear or both surfaces of thin foil targets. The originating surface of the deuterons is therefore known and this method is used to assess the relative source contributions and maximum energies using a Thomson parabola spectrometer to obtain high-resolution light-ion spectra. Under these experimental conditions, laser intensity of (0.5–2.5) _ 10 19 W cm _2 , pulse duration of 400 fs and target thickness of 6–13 µm, deuterons originating from the front surface can gain comparable maximum energies as those from the rear surface and spectra from either side can deviate from Maxwellian. Two-dimensional particle-in-cell simulations model the acceleration and show that any presence of a proton rich contamination layer over the surface is detrimental to the deuteron acceleration from the rear surface, whereas it is likely to be less influential on the front side acceleration mechanism.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90782/1/0741-3335_53_1_014011.pd
In-situ Tuning of the Electric Dipole Strength of a Double Dot Charge Qubit: Charge Noise Protection and Ultra Strong Coupling
Semiconductor quantum dots, where electrons or holes are isolated via
electrostatic potentials generated by surface gates, are promising building
blocks for semiconductor-based quantum technology. Here, we investigate double
quantum dot (DQD) charge qubits in GaAs, capacitively coupled to high-impedance
SQUID array and Josephson junction array resonators. We tune the strength of
the electric dipole interaction between the qubit and the resonator in-situ
using surface gates. We characterize the qubit-resonator coupling strength,
qubit decoherence, and detuning noise affecting the charge qubit for different
electrostatic DQD configurations. We find that all quantities can be tuned
systematically over more than one order of magnitude, resulting in reproducible
decoherence rates MHz in the limit of high interdot
capacitance. Conversely, by reducing the interdot capacitance, we can increase
the DQD electric dipole strength, and therefore its coupling to the resonator.
By employing a Josephson junction array resonator with an impedance of
k and a resonance frequency of GHz, we observe
a coupling strength of MHz, demonstrating the possibility to
achieve the ultrastrong coupling regime (USC) for electrons hosted in a
semiconductor DQD. These results are essential for further increasing the
coherence of quantum dot based qubits and investigating USC physics in
semiconducting QDs.Comment: 24 pages, 13 figure
Comparison of bulk and pitcher-catcher targets for laser-driven neutron production
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98756/1/PhysPlasmas_18_083106.pd
Introduction: Examined Live – An Epistemological Exchange Between Philosophy and Cultural Psychology on Reflection
Besides the general agreement about the human capability of reflection, there is a large area of disagreement and debate about the nature and value of “reflective scrutiny” and the role of “second-order states” in everyday life. This problem has been discussed in a vast and heterogeneous literature about topics such as epistemic injustice, epistemic norms, agency, understanding, meta-cognition etc. However, there is not yet any extensive and interdisciplinary work, specifically focused on the topic of the epistemic value of reflection. This volume is one of the first attempts aimed at providing an innovative contribution, an exchange between philosophy, epistemology and psychology about the place and value of reflection in everyday life.
Our goal in the next sections is not to offer an exhaustive overview of recent work on epistemic reflection, nor to mimic all of the contributions made by the chapters in this volume. We will try to highlight some topics that have motivated a new resumption of this field and, with that, drawing on chapters from this volume where relevant.
Two elements defined the scope and content of this volume, on the one hand, the crucial contribution of Ernest Sosa, whose works provide original and thought-provoking contributions to contemporary epistemology in setting a new direction for old dilemmas about the nature and value of knowledge, giving a central place to reflection. On the other hand, the recent developments of cultural psychology, in the version of the “Aalborg approach”, reconsider the object and scope of psychological sciences, stressing that “[h]uman conduct is purposeful”
International Guillain-Barré Syndrome Outcome Study (IGOS): protocol of a prospective observational cohort study on clinical and biological predictors of disease course and outcome in Guillain-Barré syndrome
Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy with a highly variable clinical presentation, course, and outcome. The factors that determine the clinical variation of GBS are poorly understood which complicates the care and treatment of individual patients. The protocol of the ongoing International GBS Outcome Study (IGOS), a prospective, observational, multi-centre cohort study that aims to identify the clinical and biological determinants and predictors of disease onset, subtype, course and outcome of GBS is presented here. Patients fulfilling the diagnostic criteria for GBS, regardless of age, disease severity, variant forms, or treatment, can participate if included within two weeks after onset of weakness. Information about demography, preceding infections, clinical features, diagnostic findings, treatment, course and outcome is collected. In addition, cerebrospinal fluid and serial blood samples for serum and DNA is collected at standard time points. The original aim was to include at least 1000 patients with a follow-up of 1-3 years. Data are collected via a web-based data entry system and stored anonymously. IGOS started in May 2012 and by January 2017 included more than 1400 participants from 143 active centres in 19 countries across 5 continents. The IGOS data/biobank is available for research projects conducted by expertise groups focusing on specific topics including epidemiology, diagnostic criteria, clinimetrics, electrophysiology, antecedent events, antibodies, genetics, prognostic modelling, treatment effects and long-term outcome of GBS. The IGOS will help to standardize the international collection of data and biosamples for future research of GBS. ClinicalTrials.gov Identifier: NCT01582763
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