Non-equilibrium dynamics of an active colloidal "chucker"

We report Monte Carlo simulations of the dynamics of a "chucker": a colloidal particle which emits smaller solute particles from its surface, isotropically and at a constant rate k_c. We find that the diffusion constant of the chucker increases for small k_c, as recently predicted theoretically. At large k_c the chucker diffuses more slowly due to crowding effects. We compare our simulation results to those of a "point particle" Langevin dynamics scheme in which the solute concentration field is calculated analytically, and in which hydrodynamic effects can be included albeit in an approximate way. By simulating the dragging of a chucker, we obtain an estimate of its apparent mobility coefficient which violates the fluctuation-dissipation theorem. We also characterise the probability density profile for a chucker which sediments onto a surface which either repels or absorbs the solute particles, and find that the steady state distributions are very different in the two cases. Our simulations are inspired by the biological example of exopolysaccharide-producing bacteria, as well as by recent experimental, simulation and theoretical work on phoretic colloidal "swimmers".Comment: re-submission after referee's comment

Hospital environment as a reservoir for cross transmission. Cleaning and disinfection procedures

Background. Healthcare associated infections (HAIs) represent a serious problem for public health, as they increase the morbidity and mortality rates, present a relevant financial burden, and significantly contribute to the antimicrobial resistance. Methods. The aim of this review was to investigate the literature about HAIs, with particular reference to hospital environments and the role of cleaning and disinfection procedures. Hospital environments are an essential reservoir for HAIs cross transmission, and the application of appropriate procedures related to hand hygiene and disinfection/sterilization of surfaces and instruments remain key strategies for controlling HAIs. Results. Different procedures, based on the risk associated with the healthcare procedure, are recommended for hand hygiene: washing with soap and water, antiseptic rubbing with alcohol-based disinfectants, antiseptic and surgical hand washing. Environmental surfaces can be treated with different products, and the mostly used are chlorine-based and polyphenolic disinfectant. The reprocessing of instruments is related to their use according to the Spaulding's classification. In addition, scientific evidence demonstrated the great relevance of the "bundles" (small set of practices performed together) in controlling HAIs. Conclusions. Research agenda should include the improvement of well-known effective preventive procedures and the development of new bundles devoted to high-risk procedures and specific microorganisms

Dissociative symptoms in female patients with mood and anxiety disorders: a psychopathological and temperamental investigation.

Abstract OBJECTIVE: Dissociative symptoms are frequent among psychiatric patients and may considerably affect patients' psychopathological condition and treatment outcomes. The objectives of the study are to assess the presence of dissociative symptoms in female patients with mood and anxiety disorders, to investigate their correlation with the clinical severity of the disorders and to investigate those personality traits that are more frequent in patients with high levels of dissociation. PATIENTS AND METHODS: 50 Caucasian females were enrolled in the study. Patients were assessed through the Self-Report Symptom Check-List, the Dissociative Experiences Scale (DES) and rating scales for Depression and Anxiety. RESULTS: The mean DES score in the overall sample was 16.6. 32% of patients had a DES score > 20. Depressive symptoms positively correlated with the DES total scores. Dissociator patients presented some significantly different temperamental characteristics in comparison with non dissociator patients. CONCLUSIONS: Dissociative symptoms are highly present in patients with mood and anxiety disorders and correlate with the severity of depressive symptoms. Specific personality traits more frequently observed in dissociator people may represent predisposing factors; their early identification could be clinically relevant

Crystallization of hard-sphere glasses

We study by molecular dynamics the interplay between arrest and crystallization in hard spheres. For state points in the plane of volume fraction ($0.54 \leq phi \leq 0.63$) and polydispersity ($0 \leq s \leq 0.085$), we delineate states that spontaneously crystallize from those that do not. For noncrystallizing (or precrystallization) samples we find isodiffusivity lines consistent with an ideal glass transition at $\phi_g \approx 0.585$, independent of $s$. Despite this, for $s<0.05$, crystallization occurs at $\phi > \phi_g$. This happens on time scales for which the system is aging, and a diffusive regime in the mean square displacement is not reached; by those criteria, the system is a glass. Hence, contrary to a widespread assumption in the colloid literature, the occurrence of spontaneous crystallization within a bulk amorphous state does not prove that this state was an ergodic fluid rather than a glass.Comment: 4 pages, 3 figure

Consumption patterns of social assistance (Bansos) recipients in the Bangka Belitung Islands Province

Poverty is one of the main problems in economic development, and various efforts are made to improve and expand social assistance programs (Bansos). This study aims to analyze the consumption patterns of Bansos recipients in Bangka Belitung Province. The data used are secondary data from various related agencies and primary data sourced from surveys on Bansos recipient households. The scope of the research covers two districts with the highest and lowest number of beneficiary households in the Province of Bangka Belitung Islands. The analytical method used is linear regression analysis. The results showed that Bansos significantly affected public spending, especially food spending, cellphone credit, and business capital. On the other hand, the provision of Bansos does not significantly affect expenditures such as non-food consumption, education, health, cigarettes, and debt paymen

Local structure of liquid carbon controls diamond nucleation

Diamonds melt at temperatures above 4000 K. There are no measurements of the steady-state rate of the reverse process: diamond nucleation from the melt, because experiments are difficult at these extreme temperatures and pressures. Using numerical simulations, we estimate the diamond nucleation rate and find that it increases by many orders of magnitude when the pressure is increased at constant supersaturation. The reason is that an increase in pressure changes the local coordination of carbon atoms from three-fold to four-fold. It turns out to be much easier to nucleate diamond in a four-fold coordinated liquid than in a liquid with three-fold coordination, because in the latter case the free-energy cost to create a diamond-liquid interface is higher. We speculate that this mechanism for nucleation control is relevant for crystallization in many network-forming liquids. On the basis of our calculations, we conclude that homogeneous diamond nucleation is likely in carbon-rich stars and unlikely in gaseous planets

VECTOR AUTO REGRESSION ANALYSIS BETWEEN EXPORT, ECONOMIC GROWTH, AND JOB OPPORTUNITY IN BANGKA BELITUNG ISLANDS PROVINCE

Purpose of the study: The economic performance of Bangka Belitung Islands province has increased during the period of 2007-2016. This is marked by the increasing growth rate of Gross Regional Domestic Product (GRDP) measured at the constant price of 68 percent. These performance improvements should be accompanied by efforts to create job opportunities (for instance, by increasing exports) to boost the economic growth. The objective of the study was to examine and analyze the causality relationship between job opportunities, exports, and economic growth in the Bangka Belitung Islands province. Methodology: This research used secondary data with Vector Auto Regression (VAR) analysis tool. Main Findings: The test results indicated that job opportunities and exports are affected by job opportunity in the previous year (t-1). Furthermore, the results of the study show that in comparison to exports, job opportunity contributes more towards the economic growth. Implications: This study implies that government may provide non-export oriented job opportunities in the province of Bangka Belitung Islands

Central scalp projection of the N30 SEP source activity after median nerve stimulation

Conflicting results have been reported about abnormalities of the N30 somatosensory evoked potential (SEP) in movement disorders. In these studies, the N30 amplitude was measured in the frontal scalp region. Our aim was to identify the scalp electrodes recording the genuine activity of the N30 generator. In 18 subjects, we recorded the scalp SEPs from 19 electrodes and found a negative potential around 30 ms reaching its maximal amplitude in the frontal region. However, neither simple visual inspection of the frontal traces nor topographic analysis could distinguish the N24 from the N30 component of the frontal negativity. Brain electrical source analysis of SEPs showed that a four dipolar source model could well explain the scalp SEP distribution. We calculated the scalp field distributions of the source activities as modeled from the scalp recordings and observed that the maximal field distribution reflecting the activity of the N30 source was in the central region, whereas that reflecting the N24 source activity was frontal. We conclude that the negative response recorded around 30 ms in the central traces represents "genuine" N30 source activity, whereas the frontal negativity, which is higher in amplitude, is a mixture of the activities of both the N30 and N24 sources. (C) 2000 John Wiley &amp; Sons, Inc. Muscle Nerve 23: 353-360, 2000

Forward Flux Sampling for rare event simulations

Rare events are ubiquitous in many different fields, yet they are notoriously difficult to simulate because few, if any, events are observed in a conventiona l simulation run. Over the past several decades, specialised simulation methods have been developed to overcome this problem. We review one recently-developed class of such methods, known as Forward Flux Sampling. Forward Flux Sampling uses a series of interfaces between the initial and final states to calculate rate constants and generate transition paths, for rare events in equilibrium or nonequilibrium systems with stochastic dynamics. This review draws together a number of recent advances, summarizes several applications of the method and highlights challenges that remain to be overcome.Comment: minor typos in the manuscript. J.Phys.:Condensed Matter (accepted for publication

Crystallization Mechanism of Hard Sphere Glasses

In supercooled liquids, vitrification generally suppresses crystallization. Yet some glasses can still crystallize despite the arrest of diffusive motion. This ill-understood process may limit the stability of glasses, but its microscopic mechanism is not yet known. Here we present extensive computer simulations addressing the crystallization of monodisperse hard-sphere glasses at constant volume (as in a colloid experiment). Multiple crystalline patches appear without particles having to diffuse more than one diameter. As these patches grow, the mobility in neighbouring areas is enhanced, creating dynamic heterogeneity with positive feedback. The future crystallization pattern cannot be predicted from the coordinates alone: crystallization proceeds by a sequence of stochastic micro-nucleation events, correlated in space by emergent dynamic heterogeneity.Comment: 4 pages 4 figures Accepted for publication in Phys. Rev. Lett., April 201