Asymptotic Behaviour of the Proper Length and Volume of the Schwarzschild Singularity

Though popular presentations give the Schwarzschild singularity as a point it is known that it is spacelike and not timelike. Thus it has a "length" and is not a "point". In fact, its length must necessarily be infinite. It has been proved that the proper length of the Qadir-Wheeler suture model goes to infinity [1], while its proper volume shrinks to zero, and the asymptotic behaviour of the length and volume have been calculated. That model consists of two Friedmann sections connected by a Schwarzschild "suture". The question arises whether a similar analysis could provide the asymptotic behaviour of the Schwarzschild black hole near the singularity. It is proved here that, unlike the behaviour for the suture model, for the Schwarzschild essential singularity $\Delta s$ $\thicksim$ $K^{1/3}\ln K$ and $V\thicksim$ $K^{-1}\ln K$, where $K$ is the mean extrinsic curvature, or the York time.Comment: 13 pages, 1 figur

Thermal instability in ionized plasma

We study magnetothermal instability in the ionized plasmas including the effects of Ohmic, ambipolar and Hall diffusion. Magnetic field in the single fluid approximation does not allow transverse thermal condensations, however, non-ideal effects highly diminish the stabilizing role of the magnetic field in thermally unstable plasmas. Therefore, enhanced growth rate of thermal condensation modes in the presence of the diffusion mechanisms speed up the rate of structure formation.Comment: Accepted for publication in Astrophysics & Space Scienc

Formation of Small-Scale Condensations in the Molecular Clouds via Thermal Instability

A systematic study of the linear thermal instability of a self-gravitating magnetic molecular cloud is carried out for the case when the unperturbed background is subject to local expansion or contraction. We consider the ambipolar diffusion, or ion-neutral friction on the perturbed states. In this way, we obtain a non-dimensional characteristic equation that reduces to the prior characteristic equation in the non-gravitating stationary background. By parametric manipulation of this characteristic equation, we conclude that there are, not only oblate condensation forming solutions, but also prolate solutions according to local expansion or contraction of the background. We obtain the conditions for existence of the Field lengths that thermal instability in the molecular clouds can occur. If these conditions establish, small-scale condensations in the form of spherical, oblate, or prolate may be produced via thermal instability.Comment: 16 page, accepted by Ap&S

SplitBox: Toward Efficient Private Network Function Virtualization

This paper presents SplitBox, an efficient system for privacy-preserving processing of network functions that are outsourced as software processes to the cloud. Specifically, cloud providers processing the network functions do not learn the network policies instructing how the functions are to be processed. First, we propose an abstract model of a generic network function based on match-action pairs. We assume that this function is processed in a distributed manner by multiple honest-but-curious cloud service providers. Then, we introduce our SplitBox system for private network function virtualization and present a proof-of-concept implementation on FastClick, an extension of the Click modular router, using a firewall as a use case. Our experimental results achieve a throughput of over 2 Gbps with 1 kB-sized packets on average, traversing up to 60 firewall rules

Decays and spectrum of bottom and bottom strange mesons

The strong decay amplitudes and radiative partial widths of orbital and radially excited states of $B$ and $B_s$ mesons are presented. These results are obtained with a nonrelativistic potential quark model, the nonrelativistic reduction of the electromagnetic transition operator, and the "$^3P_0$" model of strong decays. The predictions are compared to experiment where possible and assignments for the recently discovered states, $B_1(5721)$, $B_2^*(5747)$, $B_J(5840)$, $B_J(5970)$, $B_{s1}(5830)$, and $B_{s2}^*(5840)$, are made.Comment: 36 pages, 3 figure

A comparative experimental study of visual brain event-related potentials to a working memory task: virtual reality head-mounted display versus a desktop computer screen

Virtual reality head mounted display (VR HMD) systems are increasingly utilised in combination with electroencephalography (EEG) in the experimental study of cognitive tasks. The aim of our investigation was to determine the similarities/differences between VR HMD and the computer screen (CS) in response to an n-back working memory task by comparing visual electrophysiological event-related potential (ERP) waveforms (N1/P1/P3 components). The same protocol was undertaken for VR HMD and CS with participants wearing the same EEG headcap. ERP waveforms obtained with the VR HMD environment followed a similar time course to those acquired in CS. The P3 mean and peak amplitudes obtained in VR HMD were not significantly different to those obtained in CS. In contrast, the N1 component was significantly higher in mean and peak amplitudes for the VR HMD environment compared to CS at the frontal electrodes. Significantly higher P1 mean and peak amplitudes were found at the occipital region compared to the temporal for VR HMD. Our results show that successful acquisition of ERP components to a working memory task is achievable by combining VR HMD with EEG. In addition, the higher amplitude N1/P1 components seen in VR HMD indicates the potential utility of this VR modality in the investigation of early ERPs. In conclusion, the combination of VR HMD with EEG/ERP would be a useful approach to advance the study of cognitive function in experimental brain research

Fast privacy-preserving network function outsourcing

In this paper, we present the design and implementation of SplitBox, a system for privacy-preserving processing of network functions outsourced to cloud middleboxes—i.e., without revealing the policies governing these functions. SplitBox is built to provide privacy for a generic network function that abstracts the functionality of a variety of network functions and associated policies, including firewalls, virtual LANs, network address translators (NATs), deep packet inspection, and load balancers. We present a scalable design aiming to provide high throughput and low latency, by distributing functionalities to a few virtual machines (VMs), while providing provably secure guarantees. We implement SplitBox inside FastClick, an extension of the Click modular router, using Intel's DPDK to handle packet I/O. We evaluate our prototype experimentally to find its bottlenecks and stress-test its different components, vis-à-vis two widely used network functions, i.e., firewall and VLAN tagging. Our evaluation shows that, on commodity hardware, SplitBox can process packets close to line rate (i.e., 8.9Gbps) with up to 50 traversed policies

Implementation of Patient-Centered Education for Chronic-Disease Management in Uganda: An Effectiveness Study.

BACKGROUND: The majority of non-communicable disease related deaths occur in low- and middle-income countries. Patient-centered care is an essential component of chronic disease management in high income settings. OBJECTIVE: To examine feasibility of implementation of a validated patient-centered education tool among patients with heart failure in Uganda. DESIGN: Mixed-methods, prospective cohort. SETTINGS: A private and public cardiology clinic in Mulago National Referral and Teaching Hospital, Kampala, Uganda. PARTICIPANTS: Adults with a primary diagnosis of heart failure. INTERVENTIONS: PocketDoktor Educational Booklets with patient-centered health education. MAIN MEASURES: The primary outcomes were the change in Patient Activation Measure (PAM-13), as well as the acceptability of the PocketDoktor intervention, and feasibility of implementing patient-centered education in outpatient clinical settings. Secondary outcomes included the change in satisfaction with overall clinical care and doctor-patient communication. KEY RESULTS: A total of 105 participants were enrolled at two different clinics: the Mulago Outpatient Department (public) and the Uganda Heart Institute (private). 93 participants completed follow up at 3 months and were included in analysis. The primary analysis showed improved patient activation measure scores regarding disease-specific knowledge, treatment options and prevention of exacerbations among both groups (mean change 0.94 [SD = 1.01], 1.02 [SD = 1.15], and 0.92 [SD = 0.89] among private paying patients and 1.98 [SD = 0.98], 1.93 [SD = 1.02], and 1.45 [SD = 1.02] among public paying patients, p<0.001 for all values) after exposure to the intervention; this effect was significantly larger among indigent patients. Participants reported that materials were easy to read, that they had improved knowledge of disease, and stated improved communication with physicians. CONCLUSIONS: Patient-centered medical education can improve confidence in self-management as well as satisfaction with doctor-patient communication and overall care in Uganda. Our results show that printed booklets are locally appropriate, highly acceptable and feasible to implement in an LMIC outpatient setting across socioeconomic groups