Cosmic-ray electron injection from the ionization of nuclei

We show that the secondary electrons ejected from the ionization of heavy ions can be injected into the acceleration process that occurs at supernova remnant shocks. This electron injection mechanism works since ions are ionized during the acceleration when they move already with relativistic speed, just like ejected electrons do. Using the abundances of heavy nuclei measured in cosmic rays at Earth, we estimate the electron/proton ratio at the source to be ~10^-4, big enough to account for the nonthermal synchrotron emission observed in young SNRs. We also show that the ionization process can limit the maximum energy that heavy ions can reach.Comment: 4 pages, 1 figure, accepted for publication in Physical Review Letter

Jaringan Seksual dan Perilaku Berisiko Pengguna Napza Suntik: Episode Lain Penyebaran HIV di Indonesia

Background: Although a relative late comer to the epidemic, HIV has struck Indonesia hard. Surveillance at the Ministry of Health's drug dependence hospital showed an escalation from 0% injecting drug users (IDUs) infected in 1997 to almost 50% infected by 2001. As more injectors become infected, the potential for sexual transmission of HIV by IDUs increases. Yet, little was known about IDU sexual networks, sexual partnering patterns, the nature of sexual relationships and sex risk practices.Methods: IDUs are concentrated in major metropolitan areas across the Indonesian archipelago. The country's five largest cities (Jakarta, Surabaya, Medan, Bandung and Denpasar) were selected for inclusion here because they include various concentrations of IDU, potentially different, patterns of sexual networking and risk. Participants were recruited with the assistance of local, non-governmental organizations working on HIV/AIDS interventions targeting IDUs. A purposive sampling design sought to include subjects representing the range in known IDU characteristics at each locale. Selection criteria included active injectors who were sexually active and 18 years of age or older. Following informed consent, 52 willing respondents were interviewed using a semi- structured and open-ended interview guide. Interviews were divided into narrative passages and coded as to topical content upon entry in EZText qualitative database software.Results: Indonesian IDUs were found to commonly have regular, casual and commercial sex partners. Almost 90% were involved in a serious relationship with a spouse or girl/boy friend. Serious relationships included emotional ties and mutual expectations and obligations. The most common expectation was faithfulness, yet 75% of those with a regular sex partner had concurrent relations with casual and/or commercial partners. Most male IDUs actively pursued casual and commercial relations. Male IDUs also reported sex with transgenders and other males. Condoms were rarely used irrespective of partner category.Conclusion: The frequency of unprotected relations with a variety in types of partners suggests a high potential for the bridging of HIV to non-IDU populations in Indonesia. Information learned about types of partnerships and relations suggest different strategies will be needed for different types of partners if a generalized epidemic is to be averted

Simulation of neutrino and charged particle production and propagation in the atmosphere

A precise evaluation of the secondary particle production and propagation in the atmosphere is very important for the atmospheric neutrino oscillation studies. The issue is addressed with the extension of a previously developed full 3-Dimensional Monte-Carlo simulation of particle generation and transport in the atmosphere, to compute the flux of secondary protons, muons and neutrinos. Recent balloon borne experiments have performed a set of accurate flux measurements for different particle species at different altitudes in the atmosphere, which can be used to test the calculations for the atmospheric neutrino production, and constrain the underlying hadronic models. The simulation results are reported and compared with the latest flux measurements. It is shown that the level of precision reached by these experiments could be used to constrain the nuclear models used in the simulation. The implication of these results for the atmospheric neutrino flux calculation are discussed.Comment: 11 pages, 9 figure

Structural Relaxation and Mode Coupling in a Simple Liquid: Depolarized Light Scattering in Benzene

We have measured depolarized light scattering in liquid benzene over the whole accessible temperature range and over four decades in frequency. Between 40 and 180 GHz we find a susceptibility peak due to structural relaxation. This peak shows stretching and time-temperature scaling as known from $\alpha$ relaxation in glass-forming materials. A simple mode-coupling model provides consistent fits of the entire data set. We conclude that structural relaxation in simple liquids and $\alpha$ relaxation in glass-forming materials are physically the same. A deeper understanding of simple liquids is reached by applying concepts that were originally developed in the context of glass-transition research.Comment: submitted to New J. Phy

The metabolic cost of lowering blood pressure with hydrochlorothiazide

Abstract Background The landmark Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial (ALLHAT) placed a new spotlight on thiazide diuretics as the first-line therapy for hypertension. This is concerning as thiazide-diuretics may contribute to comorbidities associated with the current epidemic of obesity. Previous randomized clinical trials have linked thiazide diuretic treatment to insulin resistance, metabolic syndrome, and increased incidence of type 2 diabetes. Methods This proof of concept, longitudinal, randomized, double–blind study evaluated the effects of the angiotensin II receptor blocker Valsartan and the specific thiazide diuretic Hydrochlorothiazide (HCTZ) on hepatic triglyceride level (primary outcome), as well as triglyceride levels within other organs including the heart, skeletal muscle, and pancreas. Additionally, we evaluated whether myocardial function, insulin sensitivity, and insulin secretion were affected by these treatments. Results Hepatic TG levels increased by 57% post HCTZ treatment: ∆hTG HCTZ = 4.12% and remained unchanged post Valsartan treatment: ∆hTG V = 0.06%. The elevation of hepatic TG levels after HCTZ treatment was additionally accompanied by a reduction in insulin sensitivity: ∆SI HCTZ = -1.14. Treatment with Valsartan resulted in improved insulin sensitivity: ∆SI V = 1.24. Treatment-induced changes in hepatic TG levels and insulin sensitivity were statistically significant between groups (phTG = 0.0098 and pSI = 0.0345 respectively). Disposition index, DI, remained unchanged after HCTZ treatment: ∆DI HCTZ = -141 but it was increased by a factor of 2 after treatment with Valsartan: ∆DI V =1018). However, the change between groups was not statistically significant. Both therapies did not modify abdominal visceral and subcutaneous fat mass as well as myocardial structure and function. Additionally, myocardial, pancreatic, and skeletal muscle triglyceride deposits remained unchanged in both therapeutic arms. Conclusions Our findings are two-fold and relate to hepatic steatosis and insulin sensitivity. HCTZ treatment worsened hepatic steatosis measured as hepatic triglyceride content and reduced insulin sensitivity. Valsartan treatment did not affect hepatic triglyceride levels and improved insulin sensitivity. The results of this study reinforce the message that in patients at risk for type 2 diabetes it is particularly important to choose an antihypertensive regimen that lowers blood pressure without exacerbating patient’s metabolic profile

Jaringan Seksual dan Perilaku Berisiko Pengguna Napza Suntik: Episode Lain Penyebaran HIV di Indonesia

Background:  Although a relative late comer to the epidemic, HIV has struck Indonesia hard.  Surveillance at the Ministry of Health’s drug dependence hospital showed an escalation from 0% injecting drug users (IDUs) infected in 1997 to almost 50% infected by 2001.  As more injectors become infected, the potential for sexual transmission of HIV by IDUs increases.  Yet, little was known about IDU sexual networks, sexual partnering patterns, the nature of sexual relationships and sex risk practices.Methods:  IDUs are concentrated in major metropolitan areas across the Indonesian archipelago.  The country’s five largest cities (Jakarta, Surabaya, Medan, Bandung and Denpasar) were selected for inclusion here because they include various concentrations of IDU, potentially different, patterns of sexual networking and risk.  Participants were recruited with the assistance of local, non-governmental organizations working on HIV/AIDS interventions targeting IDUs.  A purposive sampling design sought to include subjects representing the range in known IDU characteristics at each locale.  Selection criteria included active injectors who were sexually active and 18 years of age or older.  Following informed consent, 52 willing respondents were interviewed using a semi- structured and open-ended interview guide.   Interviews were divided into narrative passages and coded as to topical content upon entry in EZText qualitative database software.Results: Indonesian IDUs were found to commonly have regular, casual and commercial sex partners.  Almost 90% were involved in a serious relationship with a spouse or girl/boy friend.  Serious relationships included emotional ties and mutual expectations and obligations.  The most common expectation was faithfulness, yet 75% of those with a regular sex partner had concurrent relations with casual and/or commercial partners.  Most male IDUs actively pursued casual and commercial relations.  Male IDUs also reported sex with transgenders and other males. Condoms were rarely used irrespective of partner category.Conclusion: The frequency of unprotected relations with a variety in types of partners suggests a high potential for the bridging of HIV to non-IDU populations in Indonesia.  Information learned about types of partnerships and relations suggest different strategies will be needed for different types of partners if a generalized epidemic is to be averted.Keywords: injecting drug users, HIV, sexual partner, risk network, interventio

'Werner Buttner's Paintings: From 'Werner' to 'Art' and Back Again

Contribution to a monograph on noted German painter Werner Buttner

A Survey of the Northern Sky for TeV Point Sources

A search for steady TeV point sources anywhere in the northern sky has been made with data from the Milagrito air-shower-particle detector. Over 3 x 10**9 events collected from 1997 February to 1998 May have been used in this study. No statistically significant excess above the background from the isotropic flux of cosmic rays was found for any direction of the sky with declination between -5 degrees and 71.7 degrees. Upper limits are derived for the photon flux above 1 TeV from any steady point source in the northern sky.Comment: 2 Figure

Simulation of Atmospheric Muon and Neutrino Fluxes with CORSIKA

The fluxes of atmospheric muons and neutrinos are calculated by a three dimensional Monte Carlo simulation with the air shower code CORSIKA using the hadronic interaction models DPMJET, VENUS, GHEISHA, and UrQMD. For the simulation of low energy primary particles the original CORSIKA has been extended by a parametrization of the solar modulation and a microscopic calculation of the directional dependence of the geomagnetic cut-off functions. An accurate description for the geography of the Earth has been included by a digital elevation model, tables for the local magnetic field in the atmosphere, and various atmospheric models for different geographic latitudes and annual seasons. CORSIKA is used to calculate atmospheric muon fluxes for different locations and the neutrino fluxes for Kamioka. The results of CORSIKA for the muon fluxes are verified by an extensive comparison with recent measurements. The obtained neutrino fluxes are compared with other calculations and the influence of the hadronic interaction model, the geomagnetic cut-off and the local magnetic field on the neutrino fluxes is investigated.Comment: revtex, 19 pages, 19 Postscript figures, submitted to Phys. Rev.