Discovery of Radio Emission from the Brown Dwarf LP944-20

Brown dwarfs are classified as objects which are not massive enough to sustain nuclear fusion of hydrogen, and are distinguished from planets by their ability to burn deuterium. Old (>10 Myr) brown dwarfs are expected to possess short-lived magnetic fields and, since they no longer generate energy from collapse and accretion, weak radio and X-ray emitting coronae. Several efforts have been undertaken in the past to detect chromospheric activity from the brown dwarf LP944-20 at X-ray and optical wavelengths, but only recently an X-ray flare from this object was detected. Here we report on the discovery of quiescent and flaring radio emission from this source, which represents the first detection of persistent radio emission from a brown dwarf, with luminosities that are several orders of magnitude larger than predicted from an empirical relation between the X-ray and radio luminosities of many stellar types. We show in the context of synchrotron emission, that LP944-20 possesses an unusually weak magnetic field in comparison to active dwarf M stars, which might explain the null results from previous optical and X-ray observations of this source, and the deviation from the empirical relations.Comment: Accepted to Natur

Update on inflammatory breast cancer

Inflammatory breast cancer (IBC) is both the least frequent and the most severe form of epithelial breast cancer. The diagnosis is based on clinical inflammatory signs and is reinforced by pathological findings. Significant progress has been made in the management of IBC in the past 20 years. Yet survival among IBC patients is still only one-half that among patients with non-IBC. Identification of the molecular determinants of IBC would probably lead to more specific treatments and to improved survival. In the present article we review recent advances in the molecular pathogenesis of IBC. A more comprehensive view will probably be obtained by pan-genomic analysis of human IBC samples, and by functional in vitro and in vivo assays. These approaches may offer better patient outcome in the near future

Self-Similar Solutions for Viscous and Resistive ADAF

In this paper, the self-similar solution of resistive advection dominated accretion flows (ADAF) in the presence of a pure azimuthal magnetic field is investigated. The mechanism of energy dissipation is assumed to be the viscosity and the magnetic diffusivity due to turbulence in the accretion flow. It is assumed that the magnetic diffusivity and the kinematic viscosity are not constant and vary by position and $\alpha$-prescription is used for them. In order to solve the integrated equations that govern the behavior of the accretion flow, a self-similar method is used. The solutions show that the structure of accretion flow depends on the magnetic field and the magnetic diffusivity. As, the radial infall velocity and the temperature of the flow increase, and the rotational velocity decreases. Also, the rotational velocity for all selected values of magnetic diffusivity and magnetic field is sub-Keplerian. The solutions show that there is a certain amount of magnetic field that the rotational velocity of the flow becomes zero. This amount of the magnetic field depends on the gas properties of the disc, such as adiabatic index and viscosity, magnetic diffusivity, and advection parameters. The solutions show the mass accretion rate increases by adding the magnetic diffusivity and in high magnetic pressure case, the ratio of the mass accretion rate to the Bondi accretion rate decreases as magnetic field increases. Also, the study of Lundquist and magnetic Reynolds numbers based on resistivity indicates that the linear growth of magnetorotational instability (MRI) of the flow decreases by resistivity. This property is qualitatively consistent with resistive magnetohydrodynamics (MHD) simulations.Comment: 18 pages, 3 figures, accepted by JA&

Radio Emission from Ultra-Cool Dwarfs

The 2001 discovery of radio emission from ultra-cool dwarfs (UCDs), the very low-mass stars and brown dwarfs with spectral types of ~M7 and later, revealed that these objects can generate and dissipate powerful magnetic fields. Radio observations provide unparalleled insight into UCD magnetism: detections extend to brown dwarfs with temperatures <1000 K, where no other observational probes are effective. The data reveal that UCDs can generate strong (kG) fields, sometimes with a stable dipolar structure; that they can produce and retain nonthermal plasmas with electron acceleration extending to MeV energies; and that they can drive auroral current systems resulting in significant atmospheric energy deposition and powerful, coherent radio bursts. Still to be understood are the underlying dynamo processes, the precise means by which particles are accelerated around these objects, the observed diversity of magnetic phenomenologies, and how all of these factors change as the mass of the central object approaches that of Jupiter. The answers to these questions are doubly important because UCDs are both potential exoplanet hosts, as in the TRAPPIST-1 system, and analogues of extrasolar giant planets themselves.Comment: 19 pages; submitted chapter to the Handbook of Exoplanets, eds. Hans J. Deeg and Juan Antonio Belmonte (Springer-Verlag

Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.

BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721

Implementation of a health care policy: An analysis of barriers and facilitators to practice change

BACKGROUND: Governments often create policies that rely on implementation by arms length organizations and require practice changes on the part of different segments of the health care system without understanding the differences in and complexities of these agencies. In 2000, in response to publicity about the shortening length of postpartum hospital stay, the Ontario government created a universal program offering up to a 60-hour postpartum stay and a public health follow-up to mothers and newborn infants. The purpose of this paper is to examine how a health policy initiative was implemented in two different parts of a health care system and to analyze the barriers and facilitators to achieving practice change. METHODS: The data reported came from two studies of postpartum health and service use in Ontario Canada. Data were collected from newly delivered mothers who had uncomplicated vaginal deliveries. The study samples were drawn from the same five purposefully selected hospitals for both studies. Questionnaires prior to discharge and structured telephone interviews at 4-weeks post discharge were used to collect data before and after policy implementation. Qualitative data were collected using focus groups with hospital and community-based health care practitioners and administrators at each site. RESULTS: In both studies, the respondents reflected a population of women who experienced an "average" or non-eventful hospital-based, singleton vaginal delivery. The findings of the second study demonstrated wide variance in implementation of the offer of a 60-hour stay among the sites and focus groups revealed that none of the hospitals acknowledged the 60-hour stay as an official policy. The uptake of the offer of a 60-hour stay was unrelated to the rate of offer. The percentage of women with a hospital stay of less than 25 hours and the number with the guideline that the call be within 48 hours of hospital discharge. Public health telephone contact was high although variable in relation to compliance the guideline that the call be within 48 hours of hospital discharge. Home visits were offered at consistently high rates. CONCLUSION: Policy enactment is sometimes inadequate to stimulate practice changes in health care. Policy as a tool for practice change must thoughtfully address the organizational, professional, and social contexts within which the policy is to be implemented. These contexts can either facilitate or block implementation. Our examination of Ontario's universal postpartum program provides an example of differential implementation of a common policy intended to change post-natal care practices that reflects the differential influence of context on implementation

Biomarker selection for detection of occult tumour cells in lymph nodes of colorectal cancer patients using real-time quantitative RT–PCR

Accurate identification of lymph node involvement is critical for successful treatment of patients with colorectal carcinoma (CRC). Real-time quantitative RT–PCR with a specific probe and RNA copy standard for biomarker mRNA has proven very powerful for detection of disseminated tumour cells. Which properties of biomarker mRNAs are important for identification of disseminated CRC cells? Seven biomarker candidates, CEA, CEACAM1-S/L, CEACAM6, CEACAM7-1/2, MUC2, MMP7 and CK20, were compared in a test-set of lymph nodes from 51 CRC patients (Dukes' A–D) and 10 controls. Normal colon epithelial cells, primary tumours, and different immune cells were also analysed. The biomarkers were ranked according to: (1) detection of haematoxylin/eosin positive nodes, (2) detection of Dukes' A and B patients, who developed metastases during a 54 months follow-up period and (3) identification of patients with Dukes' C and D tumours using the highest value of control nodes as cutoff. The following properties appear to be of importance; (a) no expression in immune cells, (b) relatively high and constant expression in tumour tissue irrespective of Dukes' stage and (c) no or weak downregulation in tumours compared to normal tissue. CEA fulfilled these criteria best, followed by CK20 and MUC2

Technology-dependency among patients discharged from a children's hospital: a retrospective cohort study

BACKGROUND: Advances in medical technology may be increasing the population of children who are technology-dependent (TD). We assessed the proportion of children discharged from a children's hospital who are judged to be TD, and determined the most common devices and number of prescription medications at the time of discharge. METHODS: Chart review of 100 randomly selected patients from all services discharged from a children's hospital during the year 2000. Data were reviewed independently by 4 investigators who classified the cases as TD if the failure or withdrawal of the technology would likely have adverse health consequences sufficient to require hospitalization. Only those cases where 3 or 4 raters agreed were classified as TD. RESULTS: Among the 100 randomly sampled patients, the median age was 7 years (range: 1 day to 24 years old), 52% were male, 86% primarily spoke English, and 54% were privately insured. The median length of stay was 3 days (range: 1 to 103 days). No diagnosis accounted for more than 5% of cases. 41% were deemed to be technology dependent, with 20% dependent upon devices, 32% dependent upon medications, and 11% dependent upon both devices and medications. Devices at the time of discharge included gastrostomy and jejeunostomy tubes (10%), central venous catheters (7%), and tracheotomies (1%). The median number of prescription medications was 2 (range: 0–13), with 12% of cases having 5 or more medications. Home care services were planned for 7% of cases. CONCLUSION: Technology-dependency is common among children discharged from a children's hospital

Risk factors for acute respiratory tract infections in general practitioner patients in The Netherlands: a case-control study

<p>Abstract</p> <p>Background</p> <p>Acute respiratory tract infections (ARTI) are an important public health problem. Improved identification of risk factors might enable targeted intervention. Therefore we carried out a case-control study with the aim of identifying environmental risk factors for ARTI consultations in the Dutch general population.</p> <p>Methods</p> <p>A subset of patients visiting their GP in the period of 2000–2003 with an ARTI (cases) and age-matched controls (visiting for other complaints) were included in a case-control study. They were asked to complete a questionnaire about potential risk factors. Conditional logistic regression was used to calculate odds ratio's (OR) and 95% confidence intervals (CI) to estimate the independent effect of potential risk factors.</p> <p>Results</p> <p>A total of 493 matched pairs of case and control subjects were enrolled. Exposure to persons with respiratory complaints, both inside and outside the household, was found to be an independent risk factor for visiting a GP with an ARTI (respectively OR_adj= 1.9 and OR_adj= 3.7). Participants exposed to dampness or mould at home (OR_adj=0.5) were significantly less likely to visit their GP. In accordance with the general risk of consultations for ARTI, participants with a laboratory-confirmed ARTI who were exposed to persons with respiratory complaints outside the household were also significantly more likely to visit their GP (OR_adj=2.5).</p> <p>Conclusion</p> <p>This study confirmed that heterogeneity in the general population as well as in pathogens causing ARTI makes it complicated to detect associations between potential risk factors and respiratory infections. Whereas it may be difficult to intervene on the risk posed by exposure to persons with respiratory complaints, transmission of ARTI in the general population might be reduced by improved hygienic conditions.</p