607 research outputs found
Heavy quark fragmentation functions at next-to-leading perturbative QCD
It is well-known that the dominant mechanism to produce hadronic bound states
with large transverse momentum is fragmentation. This mechanism is described by
the fragmentation functions (FFs) which are the universal and
process-independent functions. Here, we review the perturbative FFs formalism
as an appropriate tool for studying these hadronization processes and detail
the extension of this formalism at next-to-leading order (NLO). Using the
Suzuki's model, we calculate the perturbative QCD FF for a heavy quark to
fragment into a S-wave heavy meson at NLO. As an example, we study the LO and
NLO FFs for a charm quark to split into the S-wave -meson and compare our
analytic results both with experimental data and well-known phenomenological
models
Data-driven Flood Emulation: Speeding up Urban Flood Predictions by Deep Convolutional Neural Networks
Computational complexity has been the bottleneck of applying physically-based
simulations on large urban areas with high spatial resolution for efficient and
systematic flooding analyses and risk assessments. To address this issue of
long computational time, this paper proposes that the prediction of maximum
water depth rasters can be considered as an image-to-image translation problem
where the results are generated from input elevation rasters using the
information learned from data rather than by conducting simulations, which can
significantly accelerate the prediction process. The proposed approach was
implemented by a deep convolutional neural network trained on flood simulation
data of 18 designed hyetographs on three selected catchments. Multiple tests
with both designed and real rainfall events were performed and the results show
that the flood predictions by neural network uses only 0.5 % of time comparing
with physically-based approaches, with promising accuracy and ability of
generalizations. The proposed neural network can also potentially be applied to
different but relevant problems including flood predictions for urban layout
planning
On the feasibility of attribute-based encryption on Internet of Things devices
Attribute-based encryption (ABE) could be an effective cryptographic tool for the secure management of Internet of Things (IoT) devices, but its feasibility in the IoT has been under-investigated thus far. This article explores such feasibility for well-known IoT platforms, namely, Intel Galileo Gen 2, Intel Edison, Raspberry pi 1 model B, and Raspberry pi zero, and concludes that adopting ABE in the IoT is indeed feasible
Thalamic deep brain stimulation may relieve breathlessness in COPD
The cerebral mechanisms of dyspnoea (breathlessness) are not well understood. Neuroimaging studies of experimentally induced dyspnoea in healthy individuals have identified several cortical areas that might form a neural network for perception of dyspnoea [1], much like those identified for pain perception [2]. However, functional imaging studies alone do not reveal neurophysiological pathways and may miss putative targets for dyspnoea relief. The objective of this study was to assess the effects of Deep Brain Stimulation (DBS) of four different brain nuclei on the sensation of dyspnoea in an individual with Chronic Obstructive Pulmonary Disease (COPD) using an established multidimensional dyspnoea tool [3]
Modelling the evaporation of nanoparticle suspensions from heterogeneous surfaces
We present a Monte Carlo (MC) grid-based model for the drying of drops of a
nanoparticle suspension upon a heterogeneous surface. The model consists of a
generalised lattice-gas in which the interaction parameters in the Hamiltonian
can be varied to model different properties of the materials involved. We show
how to choose correctly the interactions, to minimise the effects of the
underlying grid so that hemispherical droplets form. We also include the
effects of surface roughness to examine the effects of contact-line pinning on
the dynamics. When there is a `lid' above the system, which prevents
evaporation, equilibrium drops form on the surface, which we use to determine
the contact angle and how it varies as the parameters of the model are changed.
This enables us to relate the interaction parameters to the materials used in
applications. The model has also been applied to drying on heterogeneous
surfaces, in particular to the case where the suspension is deposited on a
surface consisting of a pair of hydrophilic conducting metal surfaces that are
either side of a band of hydrophobic insulating polymer. This situation occurs
when using inkjet printing to manufacture electrical connections between the
metallic parts of the surface. The process is not always without problems,
since the liquid can dewet from the hydrophobic part of the surface, breaking
the bridge before the drying process is complete. The MC model reproduces the
observed dewetting, allowing the parameters to be varied so that the conditions
for the best connection can be established. We show that if the hydrophobic
portion of the surface is located at a step below the height of the
neighbouring metal, the chance of dewetting of the liquid during the drying
process is significantly reduced.Comment: 14 pages, 14 figure
Protective Effects of Regular Exercise Combined With Curcumin Supplementation Against Lead-Induced Cerebellar Oxidative Damage in an Animal Model
Lifestyle modifications, such as physical exercise and dietary supplements, were recommended
as protective measures against some neurological disorders. We examined the effects of
regular exercise combined with curcumin supplementation against lead-induced oxidative
damage of the cerebellum in male rats. Experimental animals (n = 50) were randomly divided
into five groups. Lead acetate (20 mg/kg) was i.p. administered to three groups (except sham
and control ones), while the sham group received ethyloleate (30 mg/kg) three times per
week. The curcumin and curcumin + exercise groups received curcumin (30 mg/kg) i.p. five
times per week for eight weeks. The exercise program consisted of progressive running on
a treadmill, speed from 15 to 22 m/min, 25 to 64 min per day, five times per week for eight
weeks. Two days after the last application, the rats were euthanized, and their cerebellum
was removed and homogenized to measure the levels of brain-derived neurotrophic factor
(BDNF) and thiobarbituric acid-reactive substances (TBARSs). Chronic administration
of lead significantly increased the cerebellar TBARS levels but did not alter considerably
the BDNF levels. Curcumin and curcumin + exercise treatments significantly lowered the
cerebellar TBARS levels; a significant increase in the BDNF level was observed in the
cerebellum of rats treated with combined intervention. Thus, regular exercise combined with
curcumin supplementation may exert a significant neuroprotective effect against lead-induced
cerebellar injury by attenuating oxidative stress and improving the brain state through an
increase in the BDNF amount.Модифікації стилю життя, такі як фізичні тренування та
вживання добавок до дієти, рекомендуються як протективні
заходи щодо низки неврологічних розладів. Ми дослідили
впливи регулярних тренувань, поєднаних з уведенням куркуміну, на індуковане свинцевою інтоксикацією оксидативне ушкодження мозочка у самців щурів. Експериментальні
тварини (n = 50) були рандомізовано поділені на п’ять груп.
Ацетат свинцю (20 мг/кг) уводився тваринам трьох груп (дві
слугували контролем). Одна з контрольних груп отримувала етилолеат (30 мг/кг) тричі на тиждень. У двох інтоксикованих групах тварини отримували 30 мг/кг куркуміну п’ять
разів на тиждень протягом восьми тижнів. Програма тренувань включала в себе прогресивно збільшувані епізоди бігу
на тредбані (від 15 до 25 м/хв, від 25 до 64 хв/добу, п’ять разів на тиждень протягом восьми тижнів). Через дві доби після закінчення курсів щурів піддавали евтаназії, мозочок видаляли та гомогенізували для вимірювання рівнів мозкового
нейротрофічного фактора (BDNF) та речовин, реактивних
щодо тіобарбітурової кислоти (TBARSs). Хронічне введення свинцю викликало вірогідне збільшення рівнів TBARS,
але не змінювало істотно рівнів BDNF. У групах «куркумін»
та «куркумін+тренування» спостерігалися значно нижчі рівні TBARS; вірогідно більший рівень BDNF у мозочку відмічався в групі з комбінацією заходів. Отже, регулярні фізичні тренування, поєднані з уведенням куркуміну, можуть
забезпечити істотний протекторний ефект щодо індукованого свинцем ушкодження мозочка, опосередкований зменшенням оксидативного стресу та поліпшенням стану мозку
завдяки певному збільшенню кількості BDNF
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