We report the discovery of two millisecond pulsars in a search for radio pulsations at the positions of Fermi-Large Area Telescope sources with no previously known counterparts, using the Nancay ...Radio Telescope. The two millisecond pulsars, PSRs J2017+0603 and J2302+4442, have rotational periods of 2.896 and 5.192 ms and are both in binary systems with low-eccentricity orbits and orbital periods of 2.2 and 125.9 days, respectively, suggesting long recycling processes. Gamma-ray pulsations were subsequently detected for both objects, indicating that they power the associated Fermi sources in which they were found. The gamma-ray light curves and spectral properties are similar to those of previously detected gamma-ray millisecond pulsars. Detailed modeling of the observed radio and gamma-ray light curves shows that the gamma-ray emission seems to originate at high altitudes in their magnetospheres. Additionally, X-ray observations revealed the presence of an X-ray source at the position of PSR J2302+4442, consistent with thermal emission from a neutron star. These discoveries along with the numerous detections of radio-loud millisecond pulsars in gamma rays suggest that many Fermi sources with no known counterpart could be unknown millisecond pulsars.
Geminga and B0656+14 are the closest pulsars with characteristic ages in the range of 100 kyr to 1 Myr. They both have spin-down powers of the order 3 x 10 super(34) ergs s super(-1) at present. The ...winds of these pulsars had most probably powered pulsar wind nebulae (PWNe) that broke up less than about 100 kyr after the birth of the pulsars. Assuming that leptonic particles accelerated by the pulsars were confined in the PWNe and were released into the interstellar medium (ISM) on breakup of the PWNe, we show that, depending on the pulsar parameters, both pulsars make a nonnegligible contribution to the local cosmic ray (CR) positron spectrum, and they may be the main contributors above several GeV. The relatively small angular distance between Geminga and B0656+14 thus implies an anisotropy in the local CR positron flux at these energies. We calculate the contribution of these pulsars to the locally observed CR electron and positron spectra depending on the pulsar birth period and the magnitude of the local CR diffusion coefficient. We further give an estimate of the expected anisotropy in the local CR positron flux. Our calculations show that within the framework of our model, the local CR positron spectrum imposes constraints on pulsar parameters for Geminga and B0656+14, notably the pulsar period at birth, and also the local interstellar diffusion coefficient for CR leptons.
The distribution of metals across the environment is increasingly becoming a major concern as they not only pollute the environment but also pose a danger to humans and animals. Human exposure to ...heavy metals often occurs as a combination of metals the synergistic effects of which can be more toxic than a single metal. The aim of this study was to investigate the effects that the metals mercury (Hg), nickel (Ni) and manganese (Mn) alone and in combination have on erythrocyte morphology and other components of the coagulation system using the haemolysis assay, scanning electron microscopy (SEM), and confocal laser scanning microscopy. Human blood was exposed to the heavy metals ex vivo, and percentage haemolysis was determined. Ultrastructural analysis of erythrocytes, platelets and fibrin networks was performed using SEM. Analysis of phosphatidylserine (PS) flip-flop was determined using confocal laser scanning microscopy. At the highest concentration of 10,000× the World Health Organization safety limit, all the metals caused haemolysis. The results showed that the exposure of erythrocytes to Hg alone and in combination with other metals displayed more haemolysis compared to Ni and Mn alone and in combination. Components of the coagulation system showed ultrastructural changes, including the formation of echinocytes and the activation of platelets with all single metals as well as the combinations. Confocal laser scanning microscopy analysis showed the presence of PS on the outer surface of the echinocytes that were exposed to metals alone and in combination. It can, therefore, be concluded that these heavy metals have a negative impact on erythrocytes and the coagulation system.
Since 2007, the Oncofertility Consortium Annual Conference has brought together a diverse network of individuals from a wide range of backgrounds and professional levels to disseminate emerging basic ...and clinical research findings in fertility preservation. This network also developed enduring educational materials to accelerate the pace and quality of field-wide scientific communication. Between 2007 and 2019, the Oncofertility Consortium Annual Conference was held as an in-person event in Chicago, IL. The conference attracted approximately 250 attendees each year representing 20 countries around the world. In 2020, however, the COVID-19 pandemic disrupted this paradigm and precluded an in-person meeting. Nevertheless, there remained an undeniable demand for the oncofertility community to convene. To maintain the momentum of the field, the Oncofertility Consortium hosted a day-long virtual meeting on March 5, 2021, with the theme of “Oncofertility Around the Globe” to highlight the diversity of clinical care and translational research that is ongoing around the world in this discipline. This virtual meeting was hosted using the vFairs ® conference platform and allowed over 700 people to participate, many of whom were first-time conference attendees. The agenda featured concurrent sessions from presenters in six continents which provided attendees a complete overview of the field and furthered our mission to create a global community of oncofertility practice. This paper provides a synopsis of talks delivered at this event and highlights the new advances and frontiers in the fields of oncofertility and fertility preservation around the globe from clinical practice and patient-centered efforts to translational research.
Curvature radiation (CR) is believed to be a dominant mechanism for creating gamma-ray emission from pulsars and is emitted by relativistic particles that are constrained to move along curved ...magnetic field lines. Additionally, synchrotron radiation (SR) is expected to be radiated by both relativistic primaries (involving cyclotron resonant absorption of radio photons and re-emission of SR photons), or secondary electron-positron pairs (created by magnetic or photon-photon pair production processes involving CR gamma rays in the pulsar magnetosphere). When calculating these high-energy spectra, especially in the context of pulsar population studies where several millions of CR and SR spectra have to be generated, it is profitable to consider approximations that would save computational time without sacrificing too much accuracy. This paper focuses on one such approximation technique, and we show that one may gain significantly in computational speed while preserving the accuracy of the spectral results.
This study correlates the readiness survey scores of bona fide first year university students with their success in a mathematically based first year module. It follows on the need for skilled ...individuals in the fields of Science and Technology that exists across the globe and is continually becoming the focus of educational institutions world-wide. Similarly, in South Africa, universities were instructed to increase their intake of students in the fields of Science and Technology so as to provide for the technology orientated needs of the country, as well as to increase participation of previously disadvantaged race groups in these fields. In response to this instruction, universities increased the number of students enrolled in Science and Technology fields by 23% in recent years. The challenge is now to ensure that these students exit the university with a suitable degree in the shortest possible time. Statistics published by the South African Council of Higher Education affirms the extent of this challenge faced by universities—only 51% of students enrolled in the fields of Science and Technology complete their 3-year undergraduate degrees, and some of them took as long as 6 years to complete the 3-year degrees. This still leaves 49% of students that either took more than 6 years to complete their degrees, or did not complete their degrees at all. The underlying cause(s) for these failures must be identified and addressed. As a starting point in this discussion, the questions that this study aim to answer are whether first year students are in fact as prepared for the challenges at university as they perceive themselves to be; and whether student readiness (or lack thereof) can be a root cause for the low throughput rates. This study determines how prepared first year students, at a leading South African university, perceive themselves to be for the demands of university and, specifically, how their perceptions of their readiness in different areas correlate with their academic success in a mathematically based module. The correlation is determined by analysing data gathered through a readiness survey that is completed by first year students at the beginning of the academic year, and their final mark in the mathematics based first year module. The survey is a standardised, self-evaluation tool originally developed by the University of Pretoria. It is also applied at the university where this study is conducted. The survey measures the preparedness of students in different areas and the empirical study shows that there is a statistically significant correlation between the perception of the students regarding their planning ability and the final mark obtained in the mathematics based module.
Education; Student readiness; Throughput rates; Student preparedness; Higher education; STEM; Mathematics.
Limited data exist on the South African Indian diet despite their high prevalence of non-communicable diseases. This study attempted to determine the dietary quality and patterns of an Indian ...population in KwaZulu-Natal with reference to the high prevalence of non-communicable disease
Two-hundred-and-fifty apparently healthy Indians, aged 35-55 years participated in a cross-sectional study where diet was assessed using a validated quantitative food frequency questionnaire. Mean intakes were compared to the World Health Organization goals. Dietary quality was determined by index construction and dietary patterns by factor analysis.
The mean daily percentage of energy (%E) from n-3 fatty acids (0.24 %E), dietary fibre (18.4 g/day) and fruit and vegetable intakes (229.4 g/day) were below the World Health Organization goals. Total fat (36.1 %E), polyunsaturated fatty acids (11.8 %E), n-6 fatty acids (11 %E) and free sugars (12.5 %E) exceeded the goals. The means for the deficient index reflected a moderate diet quality whereas, the excess index reflected good diet quality. The Pearson partial correlation coefficients between the deficient index and risk markers were weak whilst, the excess index was inversely correlated with waist circumference for the whole sample. Two factors were identified, based on the percentage of fat that contributed to each food group: factor 1 (meat and fish versus legume and cereal pattern), which accounted for added fat through food preparation; and Factor 2 (nuts and seeds versus sugars and visible fat pattern), which accounted for obvious fat. The medians for waist circumference, blood glucose, cholesterol and triglyceride levels showed significant decreasing trends for factor 1 (p < 0.05). The medians for blood glucose and cholesterol showed significant decreasing trends for factor 2 (p < 0.01).
A shortfall of fruit and vegetable, fibre and n-3 fatty acid intake in the diet is highlighted. When assessing the diet quality and patterns, guidance on the prudent use of added fats may lead to a healthier lifestyle reducing the prevalence of non-communicable diseases.
Background. The prevalent use of African traditional medicine by the general public has been reported. With commercialisation and marketing, some of the herbal medicines (HMs) used are readily ...available over the counter, most of them promoted as immune boosters. These commercial HMs have not been taken through clinical trials and other tests that would validate their composition and safety, and other properties such as their effect on laboratory diagnostic tests. Objective. To investigate the cross-reactivity of selected HMs with commonly tested drugs of abuse (DoA) using a qualitative rapid urinalysis assay. Methods. The six HMs selected were bought from local pharmacies. A rapid urinalysis screening test was performed with the Instant View Multi-Drug of Abuse Test kit from Labstix Diagnostics. Drug-free urine (DFU) was pooled from samples donated by healthy volunteers. Urine samples that had tested positive for DoA were obtained from a pharmacology laboratory. Aliquots of the urine samples were spiked with the HMs in neat and diluted form, and tested at various time intervals. Results. The results for the DFU samples spiked with the HMs remained negative. There were no significant changes in pH or specific gravity of the samples. The results of samples that had tested positive for tetrahydrocannabinol (THC) were not altered by five of the HMs when spiked at 40% v/v. The HM Ngoma Herbal Tonic Immune Booster caused false-negative results for the THC test. Conclusion. An important finding is that the herbal mixture Ngoma Herbal Tonic Immune Booster caused false-negative results for the cannabinoid screening test. It adds to the list of substances that may be potential adulterants of urine for screening tests.
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