9,515 research outputs found
Assessing SDG indicator 6.4.2 âlevel of water stressâ at major basins level
This paper describes a method to disaggregate indicator 6.4.2 (level of water stress) by major river basins. The analysis was performed using the GlobWat soil water balance model and global geospatial data consistent with national statistics published in AQUASTAT, the FAOâs global information system on water and agriculture. When a river basin spans across more than one country, the water stress calculated by country can be very different from that calculated by the river basin as the counting of the renewable freshwater resources from one country to another is highly dependent on the official agreement and treaties that regulate the flow of those resources between countries. This problem is solved hydrologically once the accounting of the water resources is done on the major river basin as a whole. The disaggregation by the river basin allows the identification of hotspots where actions should be prioritised and reveals that the area affected by a high or critical water stress spans across all continents with the exception of Oceania. It also offers the possibility of an analysis of freshwater withdrawals by sector, which may become crucial for the definition of water management policies in the context of the economic development of a country
Synthetic cathinones related fatalities: an update
Synthetic cathinones, more commonly known as "bath salts", are synthetic drugs chemically related to cathinone, a psychostimulant found in the khat plant. They are the first most consumed products among new psychoactive substances, which cause psychostimulant and hallucinogenic effects determining a number of fatalities worldwide. In this paper, we have systematically reviewed cases of synthetic cathinones-related fatalities analytically confirmed, which have occurred in the last few years.OBJECTIVE: Synthetic cathinones,
more commonly known as âbath saltsâ, are synthetic
drugs chemically related to cathinone, a
psychostimulant found in the khat plant. They are
the first most consumed products among new
psychoactive substances, which cause psychostimulant
and hallucinogenic effects determining
a number of fatalities worldwide. In this paper, we
have systematically reviewed cases of synthetic
cathinones-related fatalities analytically confirmed,
which have occurred in the last few years.
MATERIALS AND METHODS: Relevant scientific
articles were identified in Medline, Cochrane
Central, Scopus, Web of Science and Institutional/
government websites up to November 2017
using the following keywords: synthetic cathinones,
mephedrone, methylenedioxypyrovalerone,
MDPV, methylone, ethylone, buthylone, fatal
intoxication, fatalities and death.
RESULTS: In total, 20 citations met the criteria
for inclusion, representing several fatal cases
with analytically confirmed synthetic cathinones
in biological sample/s of the deceased. The
death was attributed to hyperthermia, hypertension,
cardiac arrest and more in general to the
classic serotonin syndrome. Only rarely did the
concentration of the parent drug causing fatality
overcome the value of 1 mg/L in post-mortem
biological fluids.
CONCLUSIONS: Abuse of synthetic cathinones
still represents a serious public health issue.
Systematic clinical studies on both the animal
and human model are lacking; therefore, the
only available data are from the users who experience
the possible hazardous consequences.
Analytical methodologies for the identification
of parent compounds and eventual metabolites
both in ante-mortem and post-mortem cases
need to be developed and validated. Analytical
data should be shared through different communication
platforms with the aim of stopping this
serious health threat for drug users
Teams in New Ventures: Gender, Human Capital and Motivation
Purpose- This paper dismantles the idea that sex per se explains entrepreneurial outcomes and demonstrates the influence of a gendered motivation on forging and shaping new venture teams, which is a disruptive choice affecting the future of start-ups.
Methods- A two-level research model is validated on data from the PSED II, with a system of simultaneous equations. Firstly, we test if team features affect the performance of new ventures; then, we investigate determinants of team features with a focus on sex and motivation of nascent entrepreneurs.
Findings- Human capital (HC) in terms of education and experience of team members consistently explains
venture evolution only when considering the larger team of affiliates. The HC gathered by nascent
entrepreneurs is not due to the simplistic sex condition, but rather to a gendered motivation related to the
inferior need of achievement of women.
Research limitations- Limitations of discretionary scoring assigned to items of the PSED II survey are
present, but unavoidable when processing qualitative data.
Social and Practical implications- Women need to be (culturally) educated on how to re-balance their
personal motivation towards entrepreneurship by fostering their incentives for achievement. Political and
educational programs could trigger success in the creation of new businesses led by women.
Originality/value- This paper contributes to the literature on nascent entrepreneurship, focusing on the
entrepreneurial teams in the initial phase of business creation, and provides the basis for further studies
aimed at eradicating the stereotypes of gender roles that lead women to self-exclusion and organizational
errors
Orbital magnetism in axially deformed sodium clusters: From scissors mode to dia-para magnetic anisotropy
Low-energy orbital magnetic dipole excitations, known as scissors mode (SM),
are studied in alkali metal clusters. Subsequent dynamic and static effects are
explored. The treatment is based on a self-consistent microscopic approach
using the jellium approximation for the ionic background and the Kohn-Sham mean
field for the electrons. The microscopic origin of SM and its main features
(structure of the mode in light and medium clusters, separation into low- and
high-energy plasmons, coupling high-energy M1 scissors and E2 quadrupole
plasmons, contributions of shape isomers, etc) are discussed. The scissors M1
strength acquires large values with increasing cluster size. The mode is
responsible for the van Vleck paramagnetism of spin-saturated clusters. Quantum
shell effects induce a fragile interplay between Langevin diamagnetism and van
Vleck paramagnetism and lead to a remarkable dia-para anisotropy in magnetic
susceptibility of particular light clusters. Finally, several routes for
observing the SM experimentally are discussed.Comment: 21 pages, 7 figure
New trends of substance abuse during COVID-19 pandemic: an international perspective
In the late 2019, an epidemic of cases with severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) has spread from China to the rest of the world, resulting in a global pandemic (COronaVIrus Disease 19, COVID-19 pandemic). Starting from the first months of 2020, several restrictions have been imposed by governments to face the public health threat, impacting the usual patterns of drug abuse throughout the world (1). The temporary border closure affected the usual illicit drug route of shipping from country to country, resulting in scarcity of classic street drugs (2). Moreover, restrictive measures internationally adopted by several countries made necessary to close all the usual recreational settings in which stimulants drugs are commonly abused. On the contrary, since in house drugs abuse became the most feasible option, other private encounters might have caught on, such as chemsex (3). In particular this phenomenon, which originated mainly in the large cities of Northern Europe, has gradually spread across the continent and is now a worrying reality in western European countries. Other rising trends of substance abuse include cognitive enhancers and new psychoactive substances (4, 5). Furthermore, the consequent social isolation and the likely limited access to detoxification centers caused additional psychological distress, pushing drug addicts toward alternative psychotropic drugs, possibly through illegal online marketplaces. An international overview of the new trends of drug abuse during the current COVID-19 pandemic and the related health risks are hereby discussed, taking into consideration different points of view
Aerothermodynamic radiation studies
We have built and made operational a 6 in. electric arc driven shock tube which alloys us to study the non-equilibrium radiation and kinetics of low pressure (0.1 to 1 torr) gases processed by 6 to 12 km/s shock waves. The diagnostic system allows simultaneous monitoring of shock radiation temporal histories by a bank of up to six radiometers, and spectral histories with two optical multi-channel analyzers. A data set of eight shots was assembled, comprising shocks in N2 and air at pressures between 0.1 and 1 torr and velocities of 6 to 12 km/s. Spectrally resolved data was taken in both the non-equilibrium and equilibrium shock regions on all shots. The present data appear to be the first spectrally resolved shock radiation measurements in N2 performed at 12 km/s. The data base was partially analyzed with salient features identified
Electric charge quantization without anomalies?
In gauge theories like the standard model, the electric charges of the
fermions can be heavily constrained from the classical structure of the theory
and from the cancellation of anomalies. We argue that the anomaly conditions
are not quite as well motivated as the classical constraints, since it is
possible that new fermions could exist which cancel potential anomalies. For
this reason we examine the classically allowed electric charges of the known
fermions and we point out that the electric charge of the tau neutrino is
classically allowed to be non-zero. The experimental bound on the electric
charge of the tau neutrino is many orders of magnitude weaker than for any
other known neutrino. We discuss possible modifications of the minimal standard
model such that electric charge is quantized classically.Comment: 10 McGill/93-3
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Discovery of molecular subtypes in leiomyosarcoma through integrative molecular profiling.
Leiomyosarcoma (LMS) is a soft tissue tumor with a significant degree of morphologic and molecular heterogeneity. We used integrative molecular profiling to discover and characterize molecular subtypes of LMS. Gene expression profiling was performed on 51 LMS samples. Unsupervised clustering showed three reproducible LMS clusters. Array comparative genomic hybridization (aCGH) was performed on 20 LMS samples and showed that the molecular subtypes defined by gene expression showed distinct genomic changes. Tumors from the muscle-enriched cluster showed significantly increased copy number changes (P=0.04). A majority of the muscle-enriched cases showed loss at 16q24, which contains Fanconi anemia, complementation group A, known to have an important role in DNA repair, and loss at 1p36, which contains PRDM16, of which loss promotes muscle differentiation. Immunohistochemistry (IHC) was performed on LMS tissue microarrays (n=377) for five markers with high levels of messenger RNA in the muscle-enriched cluster (ACTG2, CASQ2, SLMAP, CFL2 and MYLK) and showed significantly correlated expression of the five proteins (all pairwise P<0.005). Expression of the five markers was associated with improved disease-specific survival in a multivariate Cox regression analysis (P<0.04). In this analysis that combined gene expression profiling, aCGH and IHC, we characterized distinct molecular LMS subtypes, provided insight into their pathogenesis, and identified prognostic biomarkers
Transitions between bursting modes in the integrated oscillator model for pancreatic β-cells
Insulin-secreting -cells of pancreatic islets of Langerhans produce bursts of electrical impulses, resulting in intracellular Ca oscillations and pulsatile insulin secretion. The mechanism for this bursting activity has been the focus of mathematical modeling for more than three decades, and as new data are acquired old models are modified and new models are developed. Comprehensive models must now account for the various modes of bursting observed in islet -cells, which include fast bursting, slow bursting, and compound bursting. One such model is the Integrated Oscillator Model (IOM), in which -cell electrical activity, intracellular Ca , and glucose metabolism interact via numerous feedforward and feedback pathways. These interactions can produce metabolic oscillations with a sawtooth time course or a pulsatile time course, reflecting very different oscillation mechanisms. In this report, we determine conditions favorable to one form of oscillations or the other, and examine the transitions between modes of bursting and the relationship of the transitions to the patterns of metabolic oscillations. Importantly, this work clarifies what can be expected in experimental measurements of -cell oscillatory activity, and suggests pathways through which oscillations of one type can be converted to oscillations of another type.R. Bertram was supported by grant number DMS-1612193 from the National Science Foundatio
Time-dependent Hamiltonian estimation for Doppler velocimetry of trapped ions
The time evolution of a closed quantum system is connected to its Hamiltonian
through Schroedinger's equation. The ability to estimate the Hamiltonian is
critical to our understanding of quantum systems, and allows optimization of
control. Though spectroscopic methods allow time-independent Hamiltonians to be
recovered, for time-dependent Hamiltonians this task is more challenging. Here,
using a single trapped ion, we experimentally demonstrate a method for
estimating a time-dependent Hamiltonian of a single qubit. The method involves
measuring the time evolution of the qubit in a fixed basis as a function of a
time-independent offset term added to the Hamiltonian. In our system the
initially unknown Hamiltonian arises from transporting an ion through a static,
near-resonant laser beam. Hamiltonian estimation allows us to estimate the
spatial dependence of the laser beam intensity and the ion's velocity as a
function of time. This work is of direct value in optimizing transport
operations and transport-based gates in scalable trapped ion quantum
information processing, while the estimation technique is general enough that
it can be applied to other quantum systems, aiding the pursuit of high
operational fidelities in quantum control.Comment: 10 pages, 8 figure
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