The Enigma of the Dark Matter

One of the great scientific enigmas still unsolved, the existence of dark matter, is reviewed. Simple gravitational arguments imply that most of the mass in the Universe, at least 90%, is some (unknown) non-luminous matter. Some particle candidates for dark matter are discussed with particular emphasis on the neutralino, a particle predicted by the supersymmetric extension of the Standard Model of particle physics. Experiments searching for these relic particles, carried out by many groups around the world, are also discussed. These experiments are becoming more sensitive every year and in fact one of the collaborations claims that the first direct evidence for dark matter has already been observed.Comment: Invited review article for the journal Contemporary Physics. The level is suitable for researchers which are non-specialists in the subject, and also for students. Latex, 20 pages, 5 figure

Diarrhoeal outcomes in young children depend on diarrhoeal cases of other household members: a cross-sectional study of 16,025 people in rural Uganda

Background: There is a limited understanding of how diarrhoeal cases across other household members influence the likelihood of diarrhoea in young children (aged 1–4 years). Methods: We surveyed 16,025 individuals from 3421 households in 17 villages in Uganda. Using logistic regressions with standard errors clustered by household, diarrhoeal cases within households were used to predict diarrhoeal outcomes in young children. Regressions were adjusted for socio-demographic, water, sanitation, and hygiene (WASH), and ecological covariates. Selection bias for households with (1632/3421) and without (1789/3421) young children was examined. Results: Diarrhoeal prevalence was 13.7% (2118/16,025) across all study participants and 18.5% (439/2368) in young children. Young children in households with any other diarrhoeal cases were 5.71 times more likely to have diarrhoea than young children in households without any other diarrhoeal cases (95% CI: 4.48–7.26), increasing to over 29 times more likely when the other diarrhoeal case was in another young child (95% CI: 16.29–54.80). Diarrhoeal cases in older household members (aged ≥ 5 years) and their influence on the likelihood of diarrhoea in young children attenuated with age. School-aged children (5–14 years) had a greater influence on diarrhoeal cases in young children (Odds Ratio 2.70, 95% CI: 2.03–3.56) than adults of reproductive age (15–49 years; Odds Ratio 1.96, 95% CI: 1.47–2.59). Diarrhoeal cases in individuals aged ≥ 50 years were not significantly associated with diarrhoeal outcomes in young children (P > 0.05). These age-related differences in diarrhoeal exposures were not driven by sex. The magnitude and significance of the odds ratios remained similar when odds ratios were compared by sex within each age group. WASH factors did not influence the likelihood of diarrhoea in young children, despite influencing the likelihood of diarrhoea in school-aged children and adults. Households with young children differed from households without young children by diarrhoeal prevalence, household size, and village WASH infrastructure and ecology. Conclusions: Other diarrhoeal cases within households strongly influence the likelihood of diarrhoea in young children, and when controlled, removed the influence of WASH factors. Future research on childhood diarrhoea should consider effects of diarrhoeal cases within households and explore pathogen transmission between household members

Neutrino Spin Flavor Precession and Leptogenesis

We argue that \Delta L=2 neutrino spin flavor precession, induced by the primordial magnetic fields, could have a significant impact on the leptogenesis process that accounts for the baryon asymmetry of the universe. Although the extra galactic magnetic fields is extremely weak at present time (about 10^{-9} Gauss), the primordial magnetic filed at the electroweak scale could be quite strong (of order 10^{17} Gauss). Therefore, at this scale, the effects of the spin flavor precession are not negligible. We show that the lepton asymmetry may be reduced by 50% due to the spin flavor precession. In addition, the leptogenesis will have different feature from the standard scenario of leptogenesis, where the lepton asymmetry continues to oscillate even after the electroweak phase transition.Comment: 5 pages, one figure. References adde

The evolving role of oestrogen receptor beta in clinical breast cancer

Controversy surrounds the potential clinical importance of oestrogen receptor (ER)β in breast cancer, and three recent papers have sought to resolve this. In the present issue of Breast Cancer Research Novelli and colleagues explored the significance of ERβ1 expression in 936 breast cancer patients, and they showed diverse relationships according to lymph node status. A second paper examined 442 breast cancers in which ERβ1 was an independent predictor of recurrence, disease-free survival and overall survival. Finally a third paper showed that ERβ2 was a powerful prognostic indicator in 757 breast cancers but this was dependent on cellular location, with nuclear ERβ2 expression predicting good survival whilst cytoplasmic expression predicted worse outcome. These papers point to a clinical role for ERβ in breast cancer and shall be discussed

Evidence of Carriage of Antimicrobial Resistant Salmonella species of Public Health and Veterinary Significance in the Intestines of House Crows \ud (Corvus splendens) in Tanzania

The Indian house crow, Corvus splendens (Vieillot) was introduced in Zanzibar, Tanzania by the British and immigrants from India in 1897 to help clean the town. The crow is responsible for polluting the environment, water sources and human surroundings by their droppings and the rubbish they carry. This behavior has led to concern that, the crows may be responsible for the spread of certain pathogens including Salmonella and their persistence in the environment.Given the zoonotic potential of Salmonella, the main aim of this study was to investigate the occurrence of antimicrobial resistant Salmonella infections in Indian house crows and to determine if the isolates were similar to those associated with disease in livestock or humans. Methods: Indian house crows were lured with meat and blood baits to land into the crow live-trap set at the Mabibo compound of the National Institute for Medical Research (NIMR) in Dar es Salaam city in Tanzania. A total of 100 house crows were captured, humanely sacrificed, and their small and large intestines were obtained by using aseptic techniques for microbiological investigations. Culture technique was employed to detect the presence of Salmonella in intestinal contents; and preliminary identification of the isolates was based on colonial characteristics on selective media and microscopic examination of smears following Gram staining. Confirmation of Salmonella species was done by biochemical tests. Antimicrobial susceptibility testing was done by using the disc diffusion method on Mueller Hinton agar. Eight isolates were identified by standard microbiological techniques as Salmonella spp. (6 suggestive of Salmonella gallinarum and 2 suggestive of S. Typhi). All isolates were found to be susceptible to ciprofloxacin but resistant to amoxicillin. Lower levels of susceptibility were noted for chloramphenicol and ceftriaxone. Our results demonstrate the presence of antimicrobial resistant Salmonella spp. in the Indian house crows’ population and provide an indication of potential public and poultry health risks associated with these birds in the coastal area. The occurrence of antibiotic resistant S. Typhi and S. gallinarum among Indian house crows has both veterinary and public health consequences as they may be transmitted to poultry and humans. This therefore provides further rationale for the public action on eradicating the house crows

Spaceborne Hybrid-FPGA System for Processing FTIR Data

Progress has been made in a continuing effort to develop a spaceborne computer system for processing readout data from a Fourier-transform infrared (FTIR) spectrometer to reduce the volume of data transmitted to Earth. The approach followed in this effort, oriented toward reducing design time and reducing the size and weight of the spectrometer electronics, has been to exploit the versatility of recently developed hybrid field-programmable gate arrays (FPGAs) to run diverse software on embedded processors while also taking advantage of the reconfigurable hardware resources of the FPGAs

Evolution of a zoonotic pathogen:investigating prophage diversity in enterohaemorrhagic Escherichia coli O157 by long-read sequencing

Enterohaemorrhagic Escherichia coli (EHEC) O157 is a zoonotic pathogen for which colonization of cattle and virulence in humans is associated with multiple horizontally acquired genes, the majority present in active or cryptic prophages. Our understanding of the evolution and phylogeny of EHEC O157 continues to develop primarily based on core genome analyses; however, such short-read sequences have limited value for the analysis of prophage content and its chromosomal location. In this study, we applied Single Molecule Real Time (SMRT) sequencing, using the Pacific Biosciences long-read sequencing platform, to isolates selected from the main sub-clusters of this clonal group. Prophage regions were extracted from these sequences and from published reference strains. Genome position and prophage diversity were analysed along with genetic content. Prophages could be assigned to clusters, with smaller prophages generally exhibiting less diversity and preferential loss of structural genes. Prophages encoding Shiga toxin (Stx) 2a and Stx1a were the most diverse, and more variable compared to prophages encoding Stx2c, further supporting the hypothesis that Stx2c-prophage integration was ancestral to acquisition of other Stx types. The concept that phage type (PT) 21/28 (Stx2a+, Stx2c+) strains evolved from PT32 (Stx2c+) was supported by analysis of strains with excised Stx-encoding prophages. Insertion sequence elements were over-represented in prophage sequences compared to the rest of the genome, showing integration in key genes such as stx and an excisionase, the latter potentially acting to capture the bacteriophage into the genome. Prophage profiling should allow more accurate prediction of the pathogenic potential of isolates

Examining the cancellation mechanism of neutron EDM in a model with dilaton-dominated susy breaking

We examine the cancellation mechanism between the different contributions to the electric dipole moment of the neutron in a model with dilaton-dominated SUSY breaking. We find these accidental cancellations occur at few points in parameter space. For a wide region of this space we must constrain the phase of $\mu$ to be of order $10^{-1}$ and have the phases of $A$ and $\mu$ strongly correlated in order to have small neutron EDM. Moreover, we consider the indirect CP violation parameter $\epsilon$ in this region where the electric dipole moment is less than the experimental limit and find that we can generate $\epsilon$ of order $10^{-6}$

Bioactive Secondary Metabolites from a New Terrestrial Streptomyces sp. TN262

During our search for Streptomyces spp. as new producers of bioactive secondary metabolites, the ethyl acetate extract of the new terrestrial Streptomyces isolate TN262 delivered eight antimicrobially active compounds. They were identified as 1-acetyl-β-carboline (1), tryptophol (2), cineromycin B (3), 2,3-dihydrocineromycin B (4), cyclo-(tyrosylprolyl) (5), 3-(hydroxyacetyl)-indole (6), brevianamide F (7), and cis-cyclo-(l-prolyl-l-leucyl) (8). Three further metabolites were detected in the unpolar fractions using GC–MS and tentatively assigned as benzophenone (9), N-butyl-benzenesulfonamide (10), and hexanedioic acid-bis-(2-ethylhexyl) ester (11). This last compound is known as plasticizer derivatives, but it has never been described from natural sources. In this article, we describe the identification of the new Streptomyces sp. isolate TN262 using its cultural characteristics, the nucleotide sequence of the corresponding 16S rRNA gene and the phylogenetic analysis, followed by optimization, large-scale fermentation, isolation of the bioactive constituents, and determination of their structures. The biological activity of compounds (2), (3), (4), and those of the unpolar fractions was addressed as well