The Effects of Chronic Mercuric Chloride Ingestion in Female Sprague–Dawley Rats on Fertility and Reproduction

Thirty-days-old female rats were chronically exposed, for 60 days, to 1or 2 mg/kg/day of mercuric chloride or an equivalent volume of water, via gavage. At 90 days of age they were mated with unexposed males. At approximately day 13 of gestation necropsies were performed on the females. Data were collected on the number of implantations and non-viable implantations in the uterus. No physical signs of Hg intoxication were seen except in weight gain. There were significantly fewer implantations in the high HgCl2 group, with significantly more non-viable implantations in the low and high HgCl2 groups, compared to controls. Lower levels of progesterone and higher levels of pituitary luteinizing hormone (LH) were found in the high HgCl2 group compared to controls, whereas pituitary follicle stimulating hormone levels (FSH), while not significant, showed a dose– response relationship to HgCl2 levels. No difference was found in the number of corpora lutea. The experiment indicated low level chronic ingestion of mercuric chloride, in female rats, while not effecting ovulation, produced disruption of implantation and fetal viability. Lower progesterone levels, higher LH, and possibly FSH levels, indicate that mercuric chloride may have a disruptive effect in the corpora lutea which manifests itself after ovulation

PENGUJIAN USABILITY WEBSITE TIME EXCELINDO MENGGUNAKAN SYSTEM USABILITY SCALE (SUS) (sTUDI KASUS: WEBSITE TIME EXCELINDO)

Pengujian usability website Time Excelindo menggunakan System Usability Scale (SUS) merupakan penelitian aksi yang bertujuan untuk mengukur tingkat kebergunaan (usability) dari website Time Excelindo.  Berdasarkan hasil pengujian yang dilakukan akan dianalisa lebih jauh lagi untuk menghasilkan rekomendasi perbaikan website untuk meningkatkan usability. Pengujian dilakukan dengan menggunakan kuesioner SUS yang berisi 10 pernyataan dan menggunakan skala Likert untuk jawabannya. Pengujian dilakukan 2 tahap, pengujian pertama dengan menggunakan kuesioner SUS untuk mengukur tingkat usability website. Dari hasil pengujian pertama kemudian dianalisa untuk menghasilkan rekomendasi perbaikan. Pengujian kedua menggunakan kuesioner SUS yang telah diberikan perlakuan dengan menambahkan hasil rekomendasi pada pernyataan yang ada. Kesimpulan yang diperoleh dari penelitian ini adalah website Time Excelindo memiliki usability yang masih dapat diterima. Namun dengan diberikan rekomendasi perbaikan, mampu meningkatkan usability website lebih baik lagi

Augmented Reality in Astrophysics

Augmented Reality consists of merging live images with virtual layers of information. The rapid growth in the popularity of smartphones and tablets over recent years has provided a large base of potential users of Augmented Reality technology, and virtual layers of information can now be attached to a wide variety of physical objects. In this article, we explore the potential of Augmented Reality for astrophysical research with two distinct experiments: (1) Augmented Posters and (2) Augmented Articles. We demonstrate that the emerging technology of Augmented Reality can already be used and implemented without expert knowledge using currently available apps. Our experiments highlight the potential of Augmented Reality to improve the communication of scientific results in the field of astrophysics. We also present feedback gathered from the Australian astrophysics community that reveals evidence of some interest in this technology by astronomers who experimented with Augmented Posters. In addition, we discuss possible future trends for Augmented Reality applications in astrophysics, and explore the current limitations associated with the technology. This Augmented Article, the first of its kind, is designed to allow the reader to directly experiment with this technology.Comment: 15 pages, 11 figures. Accepted for publication in Ap&SS. The final publication will be available at link.springer.co

UK Public Sector Information and Re-use Policy – A 2008 Analysis

INTRODUCTION: Earlier antiretroviral therapy (ART) initiation reduces HIV-1 incidence. This benefit may be offset by increased transmitted drug resistance (TDR), which could limit future HIV treatment options. We analyze the epidemiological impact and cost-effectiveness of strategies to reduce TDR. METHODS: We develop a deterministic mathematical model representing Kampala, Uganda, to predict the prevalence of TDR over a 10-year period. We then compare the impact on TDR and cost-effectiveness of: (1) introduction of pre-therapy genotyping; (2) doubling use of second-line treatment to 80% (50-90%) of patients with confirmed virological failure on first-line ART; and (3) increasing viral load monitoring from yearly to twice yearly. An intervention can be considered cost-effective if it costs less than three times the gross domestic product per capita per quality adjusted life year (QALY) gained, or less than $3420 in Uganda. RESULTS: The prevalence of TDR is predicted to rise from 6.7$1612 to $2234 (IQR$450-dominated) per QALY gained. CONCLUSIONS: While earlier treatment initiation will result in a predicted increase in the proportion of patients infected with drug-resistant HIV, the absolute numbers of patients infected with drug-resistant HIV is predicted to decrease. Increasing use of second-line treatment to all patients with confirmed failure on first-line therapy is a cost-effective approach to reduce TDR. Improving access to second-line ART is therefore a major priority

A Gravitational Aharonov-Bohm Effect, and its Connection to Parametric Oscillators and Gravitational Radiation

A thought experiment is proposed to demonstrate the existence of a gravitational, vector Aharonov-Bohm effect. A connection is made between the gravitational, vector Aharonov-Bohm effect and the principle of local gauge invariance for nonrelativistic quantum matter interacting with weak gravitational fields. The compensating vector fields that are necessitated by this local gauge principle are shown to be incorporated by the DeWitt minimal coupling rule. The nonrelativistic Hamiltonian for weak, time-independent fields interacting with quantum matter is then extended to time-dependent fields, and applied to problem of the interaction of radiation with macroscopically coherent quantum systems, including the problem of gravitational radiation interacting with superconductors. But first we examine the interaction of EM radiation with superconductors in a parametric oscillator consisting of a superconducting wire placed at the center of a high Q superconducting cavity driven by pump microwaves. We find that the threshold for parametric oscillation for EM microwave generation is much lower for the separated configuration than the unseparated one, which then leads to an observable dynamical Casimir effect. We speculate that a separated parametric oscillator for generating coherent GR microwaves could also be built.Comment: 25 pages, 5 figures, YA80 conference (Chapman University, 2012

The nature of X-rays from young stellar objects in the Orion Nebula cluster—a Chandra HETGS legacy project

The Orion Nebula Cluster (ONC) is the closest site of very young (∼1 Myr) massive star formation The ONC hosts more than 1600 young and X-ray bright stars with masses ranging from ∼0.1–35 M⊙. The Chandra HETGS Orion Legacy Project observed the ONC with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 2.1 Ms. We describe the spectral extraction and cleaning processes necessary to separate overlapping spectra. We obtained 36 high-resolution spectra, which include a high-brilliance X-ray spectrum of θ1 Ori C with over 100 highly significant X-ray lines. The lines show Doppler broadening between 300 and 400 km s−1. Higher spectral diffraction orders allow us to resolve line components of high Z He-like triplets in θ1 Ori C with unprecedented spectral resolution. Long-term light curves spanning ∼20 yr show all stars to be highly variable, including the massive stars. Spectral fitting with thermal coronal emission line models reveals that most sources show column densities of up to a few times 1022 cm−2 and high coronal temperatures of 10–90 MK. We observe a bifurcation of the high-temperature component where some stars show a high component of 40 MK, while others show above 60 MK, indicating heavy flaring activity. Some lines are resolved with Doppler broadening above our threshold of ∼200 km s−1, up to 500 km s−1. This data set represents the largest collection of HETGS high-resolution X-ray spectra from young pre-main-sequence stars in a single star-forming region to date

Arrhythmogenic mechanisms in the isolated perfused hypokalaemic murine heart

AIM: Hypokalaemia is associated with a lethal form of ventricular tachycardia (VT), torsade de pointes, through pathophysiological mechanisms requiring clarification. METHODS: Left ventricular endocardial and epicardial monophasic action potentials were compared in isolated mouse hearts paced from the right ventricular epicardium perfused with hypokalaemic (3 and 4 mm [K(+)](o)) solutions. Corresponding K(+) currents were compared in whole-cell patch-clamped epicardial and endocardial myocytes. RESULTS: Hypokalaemia prolonged epicardial action potential durations (APD) from mean APD(90)s of 37.2 ± 1.7 ms (n = 7) to 58.4 ± 4.1 ms (n =7) and 66.7 ± 2.1 ms (n = 11) at 5.2, 4 and 3 mm [K(+)](o) respectively. Endocardial APD(90)s correspondingly increased from 51.6 ± 1.9 ms (n = 7) to 62.8 ± 2.8 ms (n = 7) and 62.9 ± 5.9 ms (n = 11) giving reductions in endocardial–epicardial differences, ΔAPD(90), from 14.4 ± 2.6 to 4.4 ± 5.0 and −3.4 ± 6.0 ms respectively. Early afterdepolarizations (EADs) occurred in epicardia in three of seven spontaneously beating hearts at 4 mm [K(+)](o) with triggered beats followed by episodes of non-sustained VT in nine of 11 preparations at 3 mm. Programmed electrical stimulation never induced arrhythmic events in preparations perfused with normokalemic solutions yet induced VT in two of seven and nine of 11 preparations at 4 and 3 mm [K(+)](o) respectively. Early outward K(+) current correspondingly fell from 73.46 ± 8.45 to 61.16±6.14 pA/pF in isolated epicardial but not endocardial myocytes (n = 9) (3 mm [K(+)](o)). CONCLUSIONS: Hypokalaemic mouse hearts recapitulate the clinical arrhythmogenic phenotype, demonstrating EADs and triggered beats that might initiate VT on the one hand and reduced transmural dispersion of repolarization reflected in ΔAPD(90) suggesting arrhythmogenic substrate on the other