Fuzzy Navigation Engine: Mitigating the Cognitive Demands of Semi-Natural Locomotion

Many interfaces exist for locomotion in virtual reality, although they are rarely considered fully natural. Past research has found that using such interfaces places cognitive demands on the user, with unnatural actions and concurrent tasks competing for finite cognitive resources. Notably, using semi-natural interfaces leads to poor performance on concurrent tasks requiring spatial working memory. This paper presents an adaptive system designed to track a user\u27s concurrent cognitive task load and adjust interface parameters accordingly, varying the extent to which movement is fully natural. A fuzzy inference system is described and the results of an initial validation study are presented. Users of this adaptive interface demonstrated better performance than users of a baseline interface on several movement metrics, indicating that the adaptive interface helped users manage the demands of concurrent spatial tasks in a virtual environment. However, participants experienced some unexpected difficulties when faced with a concurrent verbal task

Copper(II)-bis(thiosemicarbazonato) complexes as anti-chlamydial agents

Lipophilic copper (Cu)-containing complexes have shown promising antibacterial activity against a range of bacterial pathogens. To examine the susceptibility of the intracellular human pathogen Chlamydia trachomatis to copper complexes containing bis(thiosemicarbazone) ligands [Cu(btsc)], we tested the in vitro effect of CuII-diacetyl- and CuII-glyoxal-bis[N(4)-methylthiosemicarbazonato] (Cu(atsm) and Cu(gtsm), respectively) on C. trachomatis. Cu(atsm) and to a greater extent, Cu(gtsm), prevented the formation of infectious chlamydial progeny. Impacts on host cell viability and respiration were also observed in addition to the Chlamydia impacts. This work suggests that copper-based complexes may represent a new lead approach for future development of new therapeutics against chlamydial infections, although host cell impacts need to be fully explored

The Formation Rate, Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey

Spectrophotometric observations at high signal-to-noise ratio were obtained of a complete sample of 347 DA white dwarfs from the Palomar Green (PG) Survey. Fits of observed Balmer lines to synthetic spectra calculated from pure-hydrogen model atmospheres were used to obtain robust values of Teff, log g, masses, radii, and cooling ages. The luminosity function of the sample, weighted by 1/Vmax, was obtained and compared with other determinations. The mass distribution of the white dwarfs is derived, after important corrections for the radii of the white dwarfs in this magnitude-limited survey and for the cooling time scales. The formation rate of DA white dwarfs from the PG is estimated to be 0.6x10^(-12) pc^(-3) yr^(-1). Comparison with predictions from a theoretical study of the white dwarf formation rate for single stars indicates that >80% of the high mass component requires a different origin, presumably mergers of lower mass double degenerate stars. In order to estimate the recent formation rate of all white dwarfs in the local Galactic disk, corrections for incompleteness of the PG, addition of the DB-DO white dwarfs, and allowance for stars hidden by luminous binary companions had to be applied to enhance the rate. An overall formation rate of white dwarfs recently in the local Galactic disk of 1.15+/-0.25x10^(-12) pc^(-3) yr^(-1) is obtained. Two recent studies of samples of nearby Galactic planetary nebulae lead to estimates around twice as high. Difficulties in reconciling these determinations are discussed.Comment: 73 pages, 18 figures, accepted for publication in the ApJ Supplemen

In Vitro Gene Expression Dissected: Chemostat Surgery for Mycobacterium Tuberculosis

A unique approach, combining defined and reproducible in vitro models with DNA microarrays, has been developed to study environmental modulation of mycobacterial gene expression. The gene expression profiles of samples of Mycobacterium tuberculosis, from independent chemostat cultures grown under defined and reproducible conditions, were found to be highly correlated. This approach is now being used to study the effect of relevant stimuli, such as limited oxygen availability, on mycobacterial gene expression. A modification of the chemostat culture system, enabling largevolume controlled batch culture, has been developed to study starvation survival. Cultures of M. tuberculosis have been maintained under nutrient-starved conditions for extended periods, with 106 – 107 bacilli surviving in a culturable state after 100 days. The design of the culture system has made it possible to control the environment and collect multiple time-course samples to study patterns of gene expression. These studies demonstrate that it is possible to perform long-term studies and obtain reproducible expression data using controlled and defined in vitro models

A Spatially Resolved `Inside-out' Outburst of IP Pegasi

We present a comprehensive photometric dataset taken over the entire outburst of the eclipsing dwarf nova IP Peg in September/October 1997. Analysis of the lightcurves taken over the long rise to the peak-of-outburst shows conclusively that the outburst started near the centre of the disc and moved outwards. This is the first dataset that spatially resolves such an outburst. The dataset is consistent with the idea that long rise times are indicative of such `inside-out' outbursts. We show how the thickness and the radius of the disc, along with the mass transfer rate change over the whole outburst. In addition, we show evidence of the secondary and the irradiation thereof. We discuss the possibility of spiral shocks in the disc; however we find no conclusive evidence of their existence in this dataset.Comment: 8 pages, 8 figures, to be appear in MNRA

The economic impact of periprosthetic infection in total hip arthroplasty

© 2020 Canadian Medical Association. All rights reserved. Background: Periprosthetic joint infection (PJI) is the third leading cause of total hip arthroplasty (THA) failure. Although controversial, 2-stage revision remains the gold standard treatment for PJI in most situations. To date, there have been few studies describing the economic impact of PJI in today\u27s health care environment. The purpose of the current study was to obtain an accurate estimate of the institutional cost associated with the management of PJI in THA and to assess the economic burden of PJI compared with primary uncomplicated THA. Methods: We conducted a review of primary THA cases and 2-stage revision THA for PJI at our institution. Patients were matched for age and body mass index. All costs associated with each procedure were recorded. Descriptive statistics were used to summarize the collected data. Mean costs, length of stay, clinic visits and readmission rates associated with the 2 cohorts were compared. Results: Fifty consecutive cases of revision THA were matched with 50 cases of uncomplicated primary THA between 2006 and 2014. Compared with the primary THA cohort, PJI was associated with a significant increase in mean length of hospital stay (26.5 v. 2.0 d, p \u3c 0.001), mean number of clinic visits (9.2 v. 3.8, p \u3c 0.001), number of readmissions (12 v. 1, p \u3c 0.001) and average overall cost (Can$38 107 v. Can$6764, t = 8.3, p \u3c 0.001). Conclusion: Treatment of PJI is a tremendous economic burden. Our data suggest a 5-fold increase in hospital expenditure in the management of PJI compared with primary uncomplicated THA

Congenital and neonatal malaria in a rural Kenyan district hospital: An eight-year analysis

<p>Abstract</p> <p>Background</p> <p>Malaria remains a significant burden in sub-Saharan Africa. However, data on burden of congenital and neonatal malaria is scarce and contradictory, with some recent studies reporting a high burden. Using prospectively collected data on neonatal admissions to a rural district hospital in a region of stable malaria endemicity in Kenya, the prevalence of congenital and neonatal malaria was described.</p> <p>Methods</p> <p>From 1^stJanuary 2002 to 31^stDecember 2009, admission and discharge information on all neonates admitted to Kilifi District Hospital was collected. At admission, blood was also drawn for routine investigations, which included a full blood count, blood culture and blood slide for malaria parasites.</p> <p>Results</p> <p>Of the 5,114 neonates admitted during the eight-year surveillance period, blood slide for malaria parasites was performed in 4,790 (93.7%). 18 (0.35%) neonates with <it>Plasmodium falciparum </it>malaria parasitaemia, of whom 11 were admitted within the first week of life and thus classified as congenital parasitaemia, were identified. 7/18 (39%) had fever. Parasite densities were low, ≤50 per μl in 14 cases. The presence of parasitaemia was associated with low haemoglobin (Hb) of <10 g/dl (χ²10.9 P = 0.001). The case fatality rate of those with and without parasitaemia was similar. <it>Plasmodium falciparum </it>parasitaemia was identified as the cause of symptoms in four neonates.</p> <p>Conclusion</p> <p>Congenital and neonatal malaria are rare in this malaria endemic region. Performing a blood slide for malaria parasites among sick neonates in malaria endemic regions is advisable. This study does not support routine treatment with anti-malarial drugs among admitted neonates with or without fever even in a malaria endemic region.</p

Effective dose coefficients for inhaled radon and its progeny: ICRP’s approach

The International Commission on Radiological Protection (ICRP) has recently published three reports on radon exposure: (i) Publication 115 on lung cancer risks from radon and radon progeny [1], (ii) Publication 126 on radiological protection against radon exposure [2] and (iii) Publication 137 on Occupational Intakes of Radionuclides (OIR), Part 3 [3]. The latter document gives doses coefficients for the inhalation of radon, thoron and their airborne progeny as well as recommendations for their use for the protection of workers. As with all other radionuclides, the effective dose coefficients are calculated with ICRP reference biokinetic and dosimetric models. Sufficient information and dosimetric data are given so that site-specific dose coefficients can be calculated based on measured aerosol parameter values