227 research outputs found
Governance of nonprofit platforms-Onboarding mechanisms for a refugee information platform
The number of refugees arriving in Europe has increased dramatically in 2015. While governments, initiatives, and volunteers have invested substantial effort into supporting refugees, an information deficit impedes the efficacy of this collaboration. Information platforms are used to tackle this information deficit. However, the onboarding process of information providers is a critical challenge for the platforms?overall success. On the basis of observations, interviews with information providers and user experience tests, we drafted a case study describing the governance strategies applied to establish a sustainable onboarding of information providers on a nonprofit information platform for refugees. Contributing to recent literature on platform governance, our results show that governance mechanisms are implemented differently for nonprofit platform ecosystems than for commercial platform ecosystems. Building on our results, we provide practical implications by deriving a platform governance strategy that supports a sustainable onboarding of information providers
User Roles on Peer-to-Peer Sharing Platforms: A Critical Review of the Literature and Recommended Remedies
The success of sharing platforms such as Airbnb and Uber sparked interests in research, practice, and legislation in equal measures. However, studies about user roles on sharing platforms are very heterogeneous and have yet not dived into the theoretical complexity of these roles. In order to prevent incomparability of results and scattered theory building, this study reviews existing literature and identifies flaws in terminology and conceptualization of user roles and in applied measurement approaches. We discuss why these flaws matter and how they can be resolved. Finally, we propose a research agenda and emphasize to study the role of the prosumer, why different user roles lead to differences in constructs, and how the transition of user roles takes place
Recovery of phosphates as struvite from urine-diverting toilets: optimization of pH, Mg:PO4 ratio and contact time to improve precipitation yield and crystal morphology
Phosphate (P) recovery from urban wastewaters is an effective strategy to address environmental
protection and resource conservation, aiming at an effective circular economy. Off-grid wastewater
treatment systems like urine-diverting toilets (UDT) can contribute to source separation towards
nutrient recovery, namely phosphorus recovery. Effectiveness of P precipitation requires a processbased
knowledge regarding pH, Mg:PO4, contact time and their interactions in P recovery and crystal
morphology. Several studies failed to see the process as a whole and how factors influence both
morphology and P recovery for UDT hydrolysed urine. This study addressed the above-mentioned
factors and their interactions, and results showed that pH and Mg:PO4 ratio are the key factors for
struvite precipitation, whereas contact time is relevant for crystal growth. The recommended set of
factors proposed (pH 8.5, Mg:PO4 ratio of 1.2:1 and 30 minutes contact time) not only promotes a
high precipitation yield – 99% of P with co-precipitation of at least 21% of ammonium (NH4
þ) – but also
leads to larger crystals with lower water solubility (10% less crystals dissolved in water after 3 days).
The obtained outcome facilitates the downstream process and leads to a more efficient slow-release
fertiliser, as less P is wasted to receiving waters by leaching, minimising eutrophication processesinfo:eu-repo/semantics/publishedVersio
Design, implementation and evaluation of a web-based computer-tailored intervention to prevent binge drinking in adolescents: study protocol
Background: Binge-drinking in adolescents is a highly prevalent healthcare problem that associates physical and
mental health complications with community implications. This paper describes the design, implementation and
evaluation of the first web-based computer tailored intervention aimed at the prevention of binge drinking in
Spanish adolescents.
Methods: The Alerta Alcohol program is based on the I-Change Model. First, feedback from focus and Delphi
groups are used for cultural adaptation and to obtain further information on the items to be included on the
program. A pilot study is then conducted to assess feasibility and to identify strengths and weaknesses. Second, a
Cluster Randomized Controlled Trial is conducted to test the effectiveness of Alerta Alcohol in students aged 16 to
18 years. The study is performed in 16 high schools from Andalusia (southern Spain), which are randomized either
to the experimental or the control condition (EC and CC). The EC receives the Alerta Alcohol intervention, which
consists of four sessions at school (baseline questionnaire, two sessions in three scenarios: at home, celebrations,
and public places, and a final evaluation). The adolescents are provided with answers related to their views of each
scenario; this information is used to provide highly specific feedback regarding their knowledge, risk perception,
self-esteem, attitude, social influence, and self-efficacy. In addition, two booster sessions are given at home to
reinforce the previous messages. The CC just completes the baseline and the final evaluation questionnaires and
then they are allowed to receive the intervention as well (as a waiting list). Evaluation takes place after four months.
The primary endpoint is binge drinking within 30 days prior to the evaluation and alcohol use in the previous
week. It is expected that Alerta Alcohol reduce the prevalence of binge drinking by 10%. Follow up analyses are
carried out to determine the differences in effectiveness according to the compliance of the program (quality of
the implementation).
Discussion: The results are expected to be applicable and may incorporate improvements in the practice of the
Healthcare and Education Systems. If the program proves to be effective, regional and eventual national
implementation should be considered.Junta de Andalucia PI-0031-201
Why are Spanish Adolescents Binge Drinkers? Focus Group with Adolescents and Parents
Binge drinking in adolescents is a worldwide public healthcare problem. The aim of this
study was to explore the perceptions about determinants of binge drinking in Spanish adolescents from the perspective of adolescents and parents. A qualitative study using fourteen semi-structured focus groups of adolescents was conducted during the 2014/2015 school year (n = 94), and four with parents (n = 19), based on the I-Change Model for health behaviour acquisition. Students had a low level of knowledge and risk perception and limited self-e cacy. Girls reported more parental control, and when they get drunk, society perceives them worse. Adolescents suggested focus preventive actions to improve self-e cacy and self-esteem. Parents were permissive about alcohol drinking
but rejected binge drinking. They o ered alcohol to their children, mainly during celebrations.
A permissive family environment, lack of control by parents, adolescents’ low-risk perception, low self-esteem and self-e cacy, as well as the increase of binge drinking in girls as part of the reduction of the gender gap, emerge as risk factors for binge drinking. Future health programmes aimed at reducing binge drinking should focus on enhancing motivational factors, self-esteem, and self-e cacy in adolescents; supervision and parental control; as well as pre-motivational factors by increasing knowledge and risk awareness, considering gender di erences
Back To The Roots: Tree-Based Algorithms for Weakly Supervised Anomaly Detection
Weakly supervised methods have emerged as a powerful tool for model-agnostic
anomaly detection at the Large Hadron Collider (LHC). While these methods have
shown remarkable performance on specific signatures such as di-jet resonances,
their application in a more model-agnostic manner requires dealing with a
larger number of potentially noisy input features. In this paper, we show that
using boosted decision trees as classifiers in weakly supervised anomaly
detection gives superior performance compared to deep neural networks. Boosted
decision trees are well known for their effectiveness in tabular data analysis.
Our results show that they not only offer significantly faster training and
evaluation times, but they are also robust to a large number of noisy input
features. By using advanced gradient boosted decision trees in combination with
ensembling techniques and an extended set of features, we significantly improve
the performance of weakly supervised methods for anomaly detection at the LHC.
This advance is a crucial step towards a more model-agnostic search for new
physics.Comment: 11 pages, 9 figure
Endothermic salts integrated in impermeable suits do not reduce heat strain during exercise
Wearing impermeable garments during work inherently leads to heat strain, even in cold
environments [1]. Phase change materials (mainly paraffin’s or salt [4]) may be used as a thermal
buffer (e.g. [2]) to reduce initial heat stress. Salts can also be used to absorb sweat, which may
enhance the cooling power from the skin.
Recently, specific encapsulated salts utilising KSCN (potassium thiocyanate) have been developed
that consume energy when the KSCN dissolves in water. The heat consumed when the KSCN
(present inside 150 g of capsules containing 60% KSCN salt) dissolves in water is 22410 J (249 J/g *
60% * 150 g). When this solving takes place over a period of 30 minutes, the average power
transfer is 12 W. One (1) g of KSCN-containing capsules absorbs close to 1 g of moisture. If we
assume that 150 g sweat extra can be evaporated from the skin, this yields an extra cooling power
of 182 W for 30 minutes. However this evaporated water from the skin is subsequently absorbed
by the KSCN in the capsules. During this absorption from the gas phase, the condensation heat is
released to the KSCN salt: about 182 W for 30 minutes. However, we hypothesise that this
condensation heat will be partly transferred to the body and partly to the environment [3],
providing a net benefit to the body.
Thus, the total cooling effect due to the salt capsules is composed of two parts:
• The cooling effect of about 12 W due to the heat consumption by the dissolving of the salts in
water;
• The cooling effect of maximal 182 W, which equals the difference between the evaporative
heat and the condensation heat. The latter is generated in the salt capsules that transfer part
of the heat to the environment.
The overall cooling effect should therefore be in between 12 W and 194 W.
The purpose of our study was to test the efficacy of a KSCN-based absorbing salt as a PCM for use
within impermeable protective clothing. We tested the PCM during 20 min of moderate exercise
in a hot (35°C, 40% relative humidity) environment, and hypothesized that thermal strain would be
lower in the PCM compared to the non-PCM condition
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