Performance of the LHCb RICH detector at the LHC Adinolfi, M.; Aglieri Rinella, G.; Albrecht, E. ...
The European physical journal. C, Particles and fields,
05/2013, Letnik:
73, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This ...provides charged particle identification over a wide momentum range, from 2–100 GeV/
c
. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (
π
, K, p) is achieved.
Background. Higher prices for unprotected sex threaten the high levels of condom use that contributed to the decline in Zimbabwe's human immunodeficiency virus (HIV) epidemic. To improve ...understanding of financial pressures competing against safer sex, we explore factors associated with the price of commercial sex in rural eastern Zimbabwe. Methods. We collected and analyzed cross-sectional data on 311 women, recruited during October-December 2010, who reported that they received payment for their most-recent or second-most-recent sex acts in the past year. Zero-inflated negative binomial models with robust standard errors clustered on female sex worker (FSW) were used to explore social and behavioral determinants of price. Results. The median price of sex was $10 (interquartile range IQR, $5-$20) per night and $10 (IQR, $5-$15) per act. Amounts paid in cash and commodities did not differ significantly. At the most-recent sex act, more-educated FSWs received 30%-74% higher payments. Client requests for condom use significantly predicted protected sex (P<.01), but clients paid on average 42.9% more for unprotected sex. Conclusions. Within a work environment where clients' preferences determine condom use, FSWs effectively use their individual capital to negotiate the terms of condom use. Strengthening FSWs' preferences for protected sex could help maintain high levels of condom use.
Grandparents throughout sub-Saharan Africa have shown immense courage and fortitude in providing care and support for AIDS-affected children. However, growing old comes with a number of challenges ...which can compromise the quality of care and support they are able to provide, particularly for children infected by HIV and enrolled on antiretroviral therapy (ART) programmes. For ART to be effective, and for infected children not to develop drug-resistance, a complex treatment regimen must be followed. Drawing on the perspectives of 25 nurses and eight grandparents of HIV-infected children in Manicaland, eastern Zimbabwe, we explore some of the challenges faced by grandparents in sustaining children's adherence to ART. These challenges, serving as barriers to paediatric ART, are poverty, immobility, deteriorating memory and poor comprehension of complex treatments. Although older HIV-infected children were found to play an active role in sustaining the adherence to their programme of treatment by contributing to income and food generating activities and reminding their guardians about check-ups and drug administration, such contribution was not available from younger children. There is therefore an urgent need to develop ART services that both take into consideration the needs of elderly guardians and acknowledge and enhance the agency of older children as active and responsible contributors to ART adherence.
This paper extends the authors previous simulation study 1, 2 that predicted the quality of the pseudo plane wave of an offset compact antenna test range (CATR). In this paper, the quiet-zone ...performance predictions are extended to rigorously incorporate the effects of probing the CATR quiet-zone using various field probes. This investigation leads to recommendations as to the optimal field probe choice and measurement uncertainties. The results of these new simulations are presented and discussed.
AIDS has increased the number of orphans and vulnerable children (OVCs) in sub-Saharan Africa who could suffer detrimental life experiences. We investigated whether OVCs have heightened risks of ...adverse reproductive health outcomes including HIV infection. Data on HIV infection, sexually transmitted infection (STI) symptoms and pregnancy, and common risk factors were collected for OVCs and non-OVCs in a population survey of 1523 teenage children in eastern Zimbabwe between July 2001 and March 2003. Multivariate logistic regression was used to test for statistical association between OVC status, adverse reproductive health outcomes and suspected risk factors.
Amongst women aged 15-18 years, OVCs had higher HIV prevalence than non-OVCs (3.2% versus 0.0%; p=0.002) and more common experience of STI symptoms (5.9% versus 3.3%; adjusted odds ratio = 1.75, 95% CI 0.80-3.80) and teenage pregnancy (8.3% versus 1.9%; 4.25, 1.58-11.42). OVCs (overall), maternal orphans and young women with an infected parent were more likely to have received no secondary school education and to have started sex and married, which, in turn, were associated with poor reproductive health. Amongst men aged 17-18 years, OVC status was not associated with HIV infection (0.5% versus 0.0%; p=1.000) or STI symptoms (2.7% versus 1.6%; p=0.529). No association was found between history of medical injections and HIV risk amongst teenage women and men.
High proportions of HIV infections, STIs and pregnancies among teenage girls in eastern Zimbabwe can be attributed to maternal orphanhood and parental HIV. Many of these could be averted through further female secondary school education. Predicted substantial expanded increases in orphanhood could hamper efforts to slow the acquisition of HIV infection in successive generations of young adults, perpetuating the vicious cycle of poverty and disease.
Substantial resources are invested in psychological support for children orphaned or otherwise made vulnerable in the context of HIV/AIDS (OVC). However, there is still only limited scientific ...evidence for greater psychological distress amongst orphans and even less evidence for the effectiveness of current support strategies. Furthermore, programmes that address established mechanisms through which orphanhood can lead to greater psychological distress should be more effective. We use quantitative and qualitative data from Eastern Zimbabwe to measure the effects of orphanhood on psychological distress and to test mechanisms for greater distress amongst orphans suggested in a recently published theoretical framework.
Orphans were found to suffer greater psychological distress than non-orphans (sex- and age-adjusted co-efficient: 0.15; 95% CI 0.03-0.26; P=0.013). Effects of orphanhood contributing to their increased levels of distress included trauma, being out-of-school, being cared for by a non-parent, inadequate care, child labour, physical abuse, and stigma and discrimination. Increased mobility and separation from siblings did not contribute to greater psychological distress in this study. Over 40% of orphaned children in the sample lived in households receiving external assistance. However, receipt of assistance was not associated with reduced psychological distress.
These findings and the ideas put forward by children and caregivers in the focus group discussions suggest that community-based programmes that aim to improve caregiver selection, increase support for caregivers, and provide training in parenting responsibilities and skills might help to reduce psychological distress. These programmes should be under-pinned by further efforts to reduce poverty, increase school attendance and support out-of-school youth.
The purpose of this study was to determine if three strains of bacteria could impact the mechanical or surface properties of a dental resin material. Resin material specimens were incubated at 37°C ...in sterile saline, tryptic soy broth supplemented with sucrose (TSBS), or TSBS inoculated with
Streptococcus mutans, Streptococcus gordonii
, or
Streptococcus sanguis
. The specimens were subjected to Fourier transform infrared spectroscopy before and after incubation. The flexural strength test was performed once a week for 6 weeks. Microhardness and scanning electron microscopy (SEM) was performed on specimens at 1 and 6 weeks. Differences in the area under the carbonyl peak were statistically significant for the specimens incubated in the media inoculated with either
S. mutans
or
S. gordonii
. To determine why
S. sanguis
did not produce changes as the other bacteria did, triethylene glycol dimethacrylate, methacrylic acid, and triethylene glycol were added to bacterial cultures at increasing concentrations. Both methacrylic acid and triethylene glycol reduced the number of colony-forming units of
S. sanguis
. Specimens incubated in TSBS, saline or in culture with
S. sanguis
demonstrated a decrease in peak stress in week 1 of the flexure strength test. SEM demonstrated that surface topology changed for those specimens incubated in culture with
S. mutans
or
S. gordonii
. The changes in surface topology demonstrated here could contribute to the secondary caries and changes in esthetic properties seen clinically with the use of resin materials in dental restorations.
To review evidence for the impact of HIV on fertility from empirical sources pertaining to African populations and to discuss the implications for surveillance based on antenatal clinic populations.
...The theoretical equivalence between the fertility rate ratio for HIV-positive to HIV-negative women and the relative odds of being infected for pregnant women compared with the general female population is demonstrated. This equivalence is used to compare fertility differentials measured in cohort studies with those calculated indirectly from antenatal clinic data. Data from case-control studies and theoretical predictions from a model of the proximate determinants of fertility and HIV incidence are used to obtain plausible explanations of the fertility differences. Estimates of population attributable change are made.
Fertility of HIV-positive women is lower than that of HIV-negative women, in all but the youngest age-group, and the differential increases with women's age and epidemic duration. Selection for early start of sexual activity explains the reverse pattern at younger ages. Lower fertility amongst HIV-positive women causes a population attributable decline in total fertility of the order of 0.4% for each percentage point HIV prevalence in the general female population.
In populations that do not use contraceptives, HIV-positive women have lower fertility principally as a result of foetal losses consequent to infection with HIV and coinfection with other sexually transmitted diseases; behavioural factors tend to enhance this differential. Other factors being equal, HIV prevalence estimates based on antenatal surveillance underestimate true prevalence in women in the childbearing years.
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