Stopping power of hot QCD plasma

The partonic energy loss has been calculated taking both the hard and soft contributions for all the $2 \to 2$ processes, revealing the importance of the individual channels. Cancellation of the intermediate separation scale has been exhibited. Subtleties related to the identical final state partons have properly been taken into account. The estimated collisional loss is compared with its radiative counter part. We show that there exists a critical energy ($E_c$) below which the collisional loss is more than its radiative counterpart. In addition, we present closed form formulas for both the collision probabilities and the stopping power ($dE/dx$)Comment: revised version, section added, 9pages with 5 figure

Vibroacoustic stimulation for fetal assessment in labour in the presence of a nonreassuring fetal heart rate trace (Review)

Background: Fetal vibroacoustic stimulation (VAS) is a simple, non-invasive technique where a device is placed on the maternal abdomen over the region of the fetal head and sound is emitted at a predetermined level for several seconds. It is hypothesised that the resultant startle reflex in the fetus and subsequent fetal heart rate (FHR) acceleration or transient tachycardia following VAS provide reassurance of fetal well-being. This technique has been proposed as a tool to assess fetal well-being in the presence of a nonreassuring cardiotocographic (CTG) trace during the first and second stages of labour. Objectives: To evaluate the clinical effectiveness and safety of VAS in the assessment of fetal well-being during labour, compared with mock or no stimulation for women with a singleton pregnancy exhibiting a nonreassuring FHR pattern. Search methods: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (6 September 2012) and reference lists of all retrieved articles. We sought unpublished trials and abstracts submitted to major international congresses and contacted expert informants. Selection criteria: All published and unpublished randomised trials that compared maternal and fetal/neonatal/infant outcomes when VAS was used to evaluate fetal status in the presence of a nonreassuring CTG trace during labour, compared with mock or no stimulation. Data collection and analysis: Two review authors independently sought to assess for inclusion all the potential studies we identified as a result of the search strategy. We planned to resolve any disagreement through discussion or, if required, to consult a third person. Where there was uncertainty about a particular study, we attempted to contact study authors for additional information. However, these attempts were unsuccessful. Main results: The search strategies yielded six studies for consideration of inclusion. However, none of these studies fulfilled the requirements for inclusion in this review. Authors' conclusions: There are currently no randomised controlled trials that address the safety and efficacy of VAS used to assess fetal well-being in labour in the presence of a nonreassuring CTG trace. Although VAS has been proposed as a simple, non-invasive tool for assessment of fetal well-being, there is insufficient evidence from randomised trials on which to base recommendations for use of VAS in the evaluation of fetal well-being in labour in the presence of a nonreassuring CTG trace

Intrapartum fetal scalp lactate sampling for fetal assessment in the presence of a non-reassuring fetal heart rate trace (Review)

Backgroun

Precision Measurement of the Neutron Spin Asymmetry A1nA_1^n and Spin-Flavor Decomposition in the Valence Quark Region

We have measured the neutron spin asymmetry $A_1^n$ with high precision at three kinematics in the deep inelastic region at $x=0.33$, 0.47 and 0.60, and $Q^2=2.7$, 3.5 and 4.8 (GeV/c)$^2$, respectively. Our results unambiguously show, for the first time, that $A_1^n$ crosses zero around $x=0.47$ and becomes significantly positive at $x=0.60$. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (pQCD) analyses based on the earlier data. However they deviate from pQCD predictions based on hadron helicity conservation.Comment: 5 pages, 2 figures, this is the final version appeared in Phys. Rev. Let

Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region

We report on measurements of the neutron spin asymmetries $A_{1,2}^n$ and polarized structure functions $g_{1,2}^n$ at three kinematics in the deep inelastic region, with $x=0.33$, 0.47 and 0.60 and $Q^2=2.7$, 3.5 and 4.8 (GeV/c)$^2$, respectively. These measurements were performed using a 5.7 GeV longitudinally-polarized electron beam and a polarized $^3$He target. The results for $A_1^n$ and $g_1^n$ at $x=0.33$ are consistent with previous world data and, at the two higher $x$ points, have improved the precision of the world data by about an order of magnitude. The new $A_1^n$ data show a zero crossing around $x=0.47$ and the value at $x=0.60$ is significantly positive. These results agree with a next-to-leading order QCD analysis of previous world data. The trend of data at high $x$ agrees with constituent quark model predictions but disagrees with that from leading-order perturbative QCD (pQCD) assuming hadron helicity conservation. Results for $A_2^n$ and $g_2^n$ have a precision comparable to the best world data in this kinematic region. Combined with previous world data, the moment $d_2^n$ was evaluated and the new result has improved the precision of this quantity by about a factor of two. When combined with the world proton data, polarized quark distribution functions were extracted from the new $g_1^n/F_1^n$ values based on the quark parton model. While results for $\Delta u/u$ agree well with predictions from various models, results for $\Delta d/d$ disagree with the leading-order pQCD prediction when hadron helicity conservation is imposed.Comment: A typing error in A_\parallel(3He) at x=0.47 in Table VII of Phys. Rev. C has been noticed and correcte

Management of subsequent pregnancy after an unexplained stillbirth

Purpose: To review the management of pregnancy after an unexplained stillbirth.Epidemiology: Approximately 1 in 200 pregnancies will end in stillbirth, of which about one-third will remain unexplained. Unexplained stillbirth is the largest single contributor to perinatal mortality. Subsequent pregnancies do not appear to have an increased risk of stillbirth, but are characterized by increased rates of intervention (induction of labor, elective cesarean section) and iatrogenic adverse outcomes (low birth weight, prematurity, emergency cesarean section and post-partum hemorrhage).Conclusions: There is no level-one evidence to guide management in this situation. Pre-pregnancy counseling is very important to detect and correct potential risk factors such as obesity, smoking and maternal disease. As timely delivery is the mainstay of management, early accurate determination of gestational age is vital. There is controversy regarding the pattern of surveillance, but evidence exists only for ultrasound and not for regular non-stress testing, nor formal fetal movement charting. There is an urgent need for more studies in this important area

Functional data analysis with application to periodically stimulated foetal heart rate data. II : functional logistic regression

We present a basis solution for the modelling of a binary response with a functional covariate plus any number of scalar covariates. This can be thought of as singular longitudinal data analysis as there are more measurements on the functional covariate than subjects in the study. The maximum likelihood parameter estimates are found using a basis expansion and a modified Fisher scoring algorithm. This technique has been extended to model a functional covariate with a repeated stimulus. We used periodically stimulated foetal heart rate tracings to predict the probability of a high risk birth outcome. It was found that these tracings could predict 94.1 per cent of the high risk pregnancies and without the stimulus, the heart rates were no more predictive than chance.13 page(s

Women's expectations of management in their next pregnancy after an unexplained stillbirth: an internet-based empirical study.

Background: Unexplained stillbirth is the largest contributor to perinatal death, accounting for one-third of stillbirths. There appears to be no increase in perinatal death rates in the pregnancies that follow an unexplained stillbirth. However, these pregnancies have increased rates of induced labour and elective caesarean section, as well as preterm birth, low birthweight, instrumental delivery, 'fetal distress' and postpartum haemorrhage. Aim: To study the wishes for future pregnancy management in women who have suffered an unexplained stillbirth. Methods: An Internet-based survey of women after an unexplained stillbirth, seeking demographic information and reproductive history, details of management of the index stillbirth and information about their wishes for subsequent pregnancy management (antenatal surveillance, early delivery and caesarean delivery). Results: Of the total respondents included in the study, 93% wanted 'testing' over and above normal pregnancy care in their next pregnancy. Of the respondents, 81% wanted early delivery and 26% wanted a Caesarean delivery, irrespective of obstetric indications. These wishes were not influenced by socio-demographic factors, management of the index stillbirth (with the exception of having had a Caesarean delivery) or advice received on management of the next pregnancy (with the exception of being advised to have an early or Caesarean delivery). Conclusions: The women surveyed wanted increased fetal surveillance and early delivery, but not necessarily elective caesarean section

Do women's perceptions of care at the time of unexplained stillbirth influence their wishes for management in subsequent pregnancy? An Internet-based empirical study

Aim: The aim of this study was to examine women's perceptions of their care at the time of unexplained stillbirth, and whether these appear to affect wishes for management in subsequent pregnancy. Methods: An Internet-based survey was conducted of women after unexplained stillbirth, seeking information about their perceptions of management, and their wishes for care in a subsequent pregnancy. Results: One hundred and five completed surveys were included in the study group. Only 18 respondents (17%) reported that the diagnosis was broken in an uncaring way. Twenty respondents (19%) felt 'rushed into making decisions'. Almost all respondents (95%) felt that they were given adequate time with the baby after delivery. Fifty-seven respondents (54%) consented to perinatal autopsy. Most women (93%) wanted additional testing in their next pregnancy, 81% wanted delivery before the due date, but only 26% wanted cesarean delivery next time. Conclusion: Women's perceptions of care at the time of an unexplained stillbirth did not appear to influence their wishes for management in the next pregnancy

Breast cancer in premenopausal women: recurrence and survival rates and relationship to hormone replacement therapy

Objectives: To determine any association between hormonal replacement therapy (HRT) usage and breast cancer recurrence and survival rates in women who were premenopausal at the time of diagnosis of breast cancer. Methods: The study group comprised 524 women who were diagnosed with breast cancer when they were premenopausal. Of these, 277 women reached menopause before recurrence of the disease, being lost to follow-up, or reaching the end of the study. In this group, 119 women took HRT to control menopausal symptoms. The majority took combined continuous estrogen-progestin treatment. Times from diagnosis to cancer recurrence or new breast cancer, to death from all causes, and to death from primary tumor were compared between HRT users and non-users. Results: Women who used HRT after their menopause had an adjusted relative risk of recurrence or new breast cancer of 0.75 (95% confidence interval (CI), 0.29-1.95) compared to that of non-users. The relative risk of death from all causes was 0.36 (95% CI, 0.11-1.16) and that of death from primary tumor was 0.24 (95% CI, 0.05-1.14). Conclusion: HRT use in women who were premenopausal at the diagnosis of primary invasive breast cancer is not associated with worse outcomes in terms of breast cancer recurrence or mortality.8 page(s