bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feeling in Control During Labor: Concepts, Correlates, and Consequences
Authors: Green Josephine M. , Baston Helen A. 
Published: December 2003

Abstract:  Background:  Many studies have revealed that a sense of control is a major contributing factor to a woman's birth experience and her subsequent well‐being. Since not all studies conceptualize “control” in the same way or distinguish between “external” and “internal” control, the purpose of this study is to advance understanding of how these senses of control relate to each other.Methods:  Questionnaires were sent to women 1 month before birth to assess their preferences and expectations and at 6 weeks after birth to discover their experiences and assess psychological outcomes. Data are presented from 1146 women. Three control outcomes were considered: feeling in control of what staff do to you, feeling in control of your own behavior, and feeling in control during contractions.Results:  Women were less likely to report being in control of staff (39.5%) than in control of their own behavior (61.0%). Approximately one‐fifth of the sample felt in control in all three ways, and another one‐fifth did not feel in control in any of them. Parity was strongly associated with feeling in control, with multiparas feeling more in control than primiparas in all cases. In logistic regression analyses, feeling in control of staff was found to relate primarily to being able to get comfortable, feeling treated with respect and as an individual, and perceiving staff as considerate. Feeling in control of one's behavior and during contractions were primarily related to aspects of pain and pain relief, but also to antenatal expectations of control. Worry about labor pain was also an important antenatal predictor for primiparas. All three control outcomes contributed independently to satisfaction, with control of staff being the most significant; relationships with emotional well‐being were also demonstrated.Conclusions:  All three types of control were important to women and contributed to psychological outcomes. Internal and external control were predicted by different groups of variables. Caregivers have the potential to make a significant difference to a woman's experience of childbirth. The ways in which women are helped to deal with pain will affect internal control; the extent to which they feel that they are actually cared about, rather than care being something that is done to them, will affect external control. Both contribute to satisfaction and emotional well‐being. (BIRTH 30:4 December 2003)
Women's Memory of Childbirth at Two Months and One Year after the Birth
Authors: Waldenström Ulla 
Published: December 2003

Abstract:  Background:  Studies of women's memory of labor and birth have generally concluded that women's recall is fairly accurate, but the findings are not unanimous. The aim of this study was to compare women's experiences of labor pain and overall experience of the birth at 2 months and 1 year after the delivery.Methods:  A longitudinal cohort study of 2,428 women recruited in early pregnancy from all antenatal clinics in Sweden during 3 weeks evenly spread during 1999–2000 was conducted. In addition to a questionnaire in early pregnancy including background data, the women completed a questionnaire at 2 months and 1 year after the birth including the same 7‐point rating scale of pain intensity and the same question about overall experience of labor and birth.Results:  Forty‐seven percent of the women made the same assessment of pain intensity, and 60 percent of childbirth overall, at 1 year as they did at 2 months after the birth. One year after the birth, 35 percent recalled pain as less severe, and 18 percent as more severe, and 24 percent said labor and birth overall was more negative, whereas 16 percent said it was more positive.Conclusion:  This study showed great variation in women's memories of labor and birth, and conclusions by some other studies, often based on analyses of group data rather than on the responses of the individual participants were, to some extent, challenged. (BIRTH 30:4 December 2003)
Effect of Operative Delivery in the Second Stage of Labor on Breastfeeding Success
Authors: Patel Roshni R. , Liebling Rachel E. , Murphy Deirdre J. 
Published: December 2003

Abstract:  Background:Operative delivery rates are currently rising in many countries, but the effects of this factor on the initiation and duration of breastfeeding are unclear. The purpose of this study was to evaluate breastfeeding success after instrumental vaginal delivery or cesarean section at full dilatation, and to investigate whether timing of discharge after operative delivery affects breastfeeding rates. Methods:  A prospective cohort study was conducted of 393 women with term, singleton, live, cephalic pregnancies who required delivery in theater during the second stage of labor between February 1999 and February 2000. Postal questionnaires were mailed to participants at 6 weeks and 1 year. Logistic regression models were used to explore the relationships between infant feeding and mode of delivery, controlling for factors previously correlated with breastfeeding success.Results:  Rates of exclusive breastfeeding at discharge and 6 weeks postpartum were 70 and 44 percent, respectively. No significant differences occurred when instrumental vaginal delivery was compared with cesarean section, adjusted OR 0.84 (95% CI 0.50, 1.41) and 1.15 (95% CI 0.69, 1.93) respectively. Breastfeeding rates after failed instrumental delivery were similar to those after immediate cesarean section, adjusted OR 0.99 (95% CI 0.72, 1.38) and 1.28 (95% CI 0.91, 1.78). Women who had a longer in‐patient stay after cesarean section were more likely to achieve exclusive breastfeeding at hospital discharge (78% vs 66%, p = 0.03).Conclusions:  Method of operative delivery in the second stage of labor does not appear to influence initiation or duration of exclusive breastfeeding. A longer inpatient stay may help cesarean‐delivered women to initiate breastfeeding. (BIRTH 30:4 December 2003)
Breastfeeding Support from Partners and Grandmothers: Perceptions of Swedish Women
Authors: Ekström Anette , Widström Ann‐Marie , Nissen Eva 
Published: December 2003

Abstract:  Background: Support from the mother's network of relatives, friends, and professional caregivers during childbirth is likely to be important for breastfeeding success. Few studies have been conducted to examine mothers’ perceptions of breastfeeding support. The objective of this study was to describe breastfeeding support and feelings of confidence of primiparas and multiparas in relation to duration of breastfeeding.Methods:  Mothers who delivered vaginally were eligible for inclusion. After receiving a questionnaire when their children were 9 to 12 months of age, 194 primiparas and 294 multiparas responded to questions on breastfeeding history and on perceived and overall breastfeeding support and feelings of confidence.Results:  Feelings of overall breastfeeding support were correlated with duration of exclusive breastfeeding in both primiparas (p < 0.001) and multiparas (p < 0.001). Multiparas who knew how long they were breastfed as a child showed a longer duration of exclusive (p = 0.006) and total (p = 0.007) breastfeeding than multiparas who did not know. The time during which the partner was present after labor was correlated with the duration of exclusive (p < 0.001) and total breastfeeding (p = 0.002) in primiparas. Feelings of confidence when the baby was 6 to12 months old, as retrospectively rated on a visual analog scale, was correlated with feelings of confidence in the partner during childbirth in both primiparas (p < 0.001) and multiparas (p < 0.001) and the experience of overall breastfeeding support (primiparas, p = 0.002; multiparas, p < 0.001). Both groups were more content with breastfeeding information they received from midwives in the maternity wards, compared with that from antenatal midwives and postnatal nurses (p < 0.001).Conclusions:  A helpful support strategy for mothers with respect to breastfeeding outcome is for health professionals to discuss the grandmother's perception of breastfeeding with the mother. It is important for perinatal caregivers to provide an environment that enables the family to stay together after delivery. A helpful support strategy for health professionals might be to mobilize grandmothers with positive breastfeeding perception to provide support for their daughters’ breastfeeding. (BIRTH 30:4 December 2003)
Women's Recognition of the Spontaneous Onset of Labor
Authors: Gross Mechthild M. , Haunschild Tanja , Stoexen Tina , Methner Viola , Guenter Hans H. 
Published: December 2003

Abstract:  Background: Despite extensive research on the onset of labor, almost no data are available on women's perception of labor onset. We undertook a study to assess how women experience spontaneous onset of term labor.Methods:  A semistructured questionnaire was given to 235 women admitted in spontaneous labor at term. Women noted when labor had started, whether and when membranes had ruptured, and answered an open question about how labor had announced itself. Two investigators independently subdivided women's experiences on how labor had started into 369 sampling units corresponding to 8 predefined categories.Results:  Nearly two‐thirds of the sampling units (63.4%) related to recurrent and nonrecurrent pain, and the ratio between the two types was higher for multiparas than for nulliparas. The number of women and sampling units were identical for each of the following categories: watery fluid (n = 47), blood‐stained loss (n = 33), gastrointestinal symptoms (n = 10) and altered sleep patterns (n = 11); 22 sampling units relating to emotional upheaval were mentioned by 16 women. Although 33.6 percent of women experienced rupture of membranes before admission, only 21.6 percent associated it with their onset of labor, either alone (11.5%) or in association with other categories (10.1%).Conclusions:  Although women experience onset of labor in a variety of ways, for most it is a concrete event. Studies on duration of labor should take women's perception of onset of labor as a starting point rather than rely on surrogate measures. (BIRTH 30:4 December 2003)
Support During Pregnancy for Women at Increased Risk of Low Birthweight Babies
Authors: Hodnett E. D. , Fredericks S. 
Published: December 2003

AbstractBackground:  Studies consistently show a relationship between social disadvantage and low birthweight. Many countries have programs offering special assistance to women thought to be at risk for giving birth to a low birthweight infant. These programs may include advice and counselling (about nutrition, rest, stress management, alcohol and recreational drug use), tangible assistance (e.g., transportation to clinic appointments, help with household responsibilities), and emotional support. The programs may be delivered by multidisciplinary teams of health professionals, by specially trained lay workers, or by a combination of lay and professional workers.Objectives:  The objective of this review was to assess the effects of programs offering additional social support for pregnant women who are believed to be at risk for giving birth to preterm or low birthweight babies.Search strategy:  We searched the Cochrane Pregnancy and Childbirth Group trials register (30 January 2003).Selection criteria:  Randomized trials of additional support during at‐risk pregnancy by either a professional (social worker, midwife, or nurse) or specially trained lay person, compared to routine care. Additional support was defined as some form of emotional support (e.g., counselling, reassurance, sympathetic listening) and information/advice, either in home visits or during clinic appointments, and could include tangible assistance (e.g., transportation to clinic appointments, assistance with the care of other children at home).Data collection and analysis:  Reviewers independently assessed trial quality and extracted data. Double data entry was performed. Study authors were contacted to request additional information.Main results:  Sixteen trials involving 13,651 women were included. The trials were generally of good to excellent quality, although 3 used an allocation method likely to introduce bias. Programs offering additional social support for at‐risk pregnant women were not associated with improvements in any perinatal outcomes, but there was a reduction in the likelihood of caesarean birth and an increased likelihood of elective termination of pregnancy. Some improvements in immediate maternal psychosocial outcomes were found in individual trials.Reviewers’ conclusions:  Pregnant women need the support of caring family members, friends, and health professionals. While programs which offer additional support during pregnancy are unlikely to prevent the pregnancy from resulting in a low birthweight or preterm baby, they may be helpful in reducing the likelihood of caesarean birth.Citation:  Hodnett ED, Fredericks S. Support during pregnancy for women at increased risk of low birthweight babies (Cochrane Review). In: The Cochrane Library, Issue 3, 2003. Oxford: Update Software.
Aerobic Exercise for Women During Pregnancy
Authors: Kramer M. S. 
Published: December 2003

AbstractBackground:  Physiological responses of the fetus (especially increase in heart rate) to single, brief bouts of maternal exercise have been documented frequently, suggesting that maternal exercise might have beneficial or adverse effects on pregnancy outcome.Objectives:  The objective of this review was to assess the effects of advising healthy pregnant women to engage in regular (at least two to three times per week) aerobic exercise on physical fitness, labour and delivery, and the outcome of pregnancy.Search strategy:  The Cochrane Pregnancy and Childbirth Group trials register was searched and researchers in the field were contacted. Date of last search: January 2002.Selection criteria:  Acceptably controlled comparisons of prescribed aerobic exercise programs.Data collection and analysis:  One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information.Main results:  Ten trials involving 688 women were included. The trials were not of high methodologic quality. Five trials reported significant improvement in physical fitness in the exercise group, although differences in measures used to assess fitness prevent a quantitative pooling of results. Six trials reported on pregnancy outcomes. A statistically significant increased risk of preterm birth (relative risk (RR) = 2.29 [95% confidence interval 1.02 to 5.13]) in the exercise group is inconsistent with the absence of effect on mean gestational age [+0.0 (−0.4 to +0.4) weeks] and may have been biased by post‐randomization exclusion of women with preterm labor. Results bearing on fetal growth (birthweight, length, and head circumference) were highly variable. One trial found improvements among exercising women in several aspects of self‐reported body image, including muscle strength, energy level, and body build.Reviewers’ conclusions:  Regular aerobic exercise during pregnancy appears to improve (or maintain) physical fitness and body image. Available data are insufficient to infer important risks or benefits for the mother or infant.Citation:  Kramer MS. Aerobic exercise for women during pregnancy (Cochrane Review). In: The Cochrane Library, Issue 3, 2003. Oxford: Update Software.
Models and Mechanisms of Experimental Epilepsies
Authors: Jefferys John G. R. 
Published: December 2003

Summary:  Purpose: To review the value of experimental models of epilepsy to help us understand the underlying basic neuronal mechanisms. Methods: The methods addressed here include a variety of acute and chronic experimental epilepsies and their investigation in vitro, in vivo, and in computer simulations. Results: Epileptic discharges are emergent properties of neuronal networks, depending crucially on intrinsic neuronal properties, and on the structural and functional organisation of the synaptic networks that interconnect them. Fast oscillations are another emergent property of these networks; while they are involved in normal function, they can play a crucial role in the initiation of at least some kinds of focal seizure. Discussion: Brief “interictal” epileptic events are now relatively well understood. Rather less so are the mechanisms of chronic epileptic foci, and particularly of the prolonged hypersynchronous hyperexcitability characteristic of focal seizures, but here too progress is being made, offering the prospect of better targeted treatments.
Sleep Oscillations Developing into Seizures in Corticothalamic Systems
Authors: Steriade M. , Amzica F. 
Published: December 2003

Summary:  Purpose: The aim of this article is to discuss the neuronal substrates of sleep oscillations leading to seizures consisting of spike–wave (SW) complexes at 2–4 Hz, mimicking those seen in absence epilepsy, or SW and polyspike–wave (PSW) complexes at 1.5–2.5 Hz, often associated with fast runs at 10–15 Hz, as in the Lennox–Gastaut syndrome. Methods: Extracellular recordings were done in permanently implanted animals during the natural waking–sleep cycle. Single and dual simultaneous recordings from cortical neurons, cortical and thalamic neurons, or cortical neurons and glial cells were performed in cats under ketamine–xylazine anesthesia. Results: (a) The minimal substrate of SW seizures is the neocortex because such seizures may occur in thalamectomized animals, in which spindles are absent. In intact‐brain animals, SW seizures are initiated in neocortex and spread to the thalamus after a few seconds. The majority of thalamocortical (TC) neurons are steadily hyperpolarized throughout the cortical SW seizures. (b) In the Lennox–Gastaut syndrome, the paroxysmal depolarizing shifts (PDSs) associated with the EEG “spike” of SW/PSW complexes contain an important inhibitory component, whereas the hyperpolarization during the EEG “wave” component is not due to γ‐aminobutryic acid (GABA)ergic inhibitory postsynaptic potentials (IPSPs) but is ascribed to a mixture of disfacilitation and K+ currents. As is also the case with seizures consisting of pure SW complexes, the majority of TC neurons are hyperpolarized during the cortical paroxysms and disinhibited after the cessation of cortical seizures. Conclusions: Seizures with SW complexes and of the Lennox–Gastaut type preferentially evolve from sleep oscillations. They are initiated in neocortex and spread to the thalamus after a few seconds. The majority of TC neurons are inhibited during these seizures.
Non parametric VaR Techniques. Myths and Realities
Authors: Barone‐Adesi Giovanni , Giannopoulos Kostas 
Published: December 2003

VaR (value‐at‐risk) estimates are currently based on two main techniques: the variance‐covariance approach or simulation. Statistical and computational problems affect the reliability of these techniques. We illustrate a new technique – filtered historical simulation (FHS) – designed to remedy some of the shortcomings of the simulation approach. We compare the estimates it produces with traditional bootstrapping estimates.(J.E.L.: G19).
Consistent High‐precision Volatility from High‐frequency Data
Authors: Corsi Fulvio , Zumbach Gilles , Muller Ulrich A. , Dacorogna Michel M. 
Published: December 2003

Estimates of daily volatility are investigated. Realized volatility can be computed from returns observed over time intervals of different sizes. For simple statistical reasons, volatility estimators based on high‐frequency returns have been proposed, but such estimators are found to be strongly biased as compared to volatilities of daily returns. This bias originates from microstructure effects in the price formation. For foreign exchange, the relevant microstructure effect is the incoherent price formation, which leads to a strong negative first‐order autocorrelation ρ(1)≃40 per cent for tick‐by‐tick returns and to the volatility bias. On the basis of a simple theoretical model for foreign exchange data, the incoherent term can be filtered away from the tick‐by‐tick price series. With filtered prices, the daily volatility can be estimated using the information contained in high‐frequency data, providing a high‐precision measure of volatility at any time interval.(J.E.L.: C13, C22, C81).
Deterministic and Stochastic Methods for Estimation of Intra‐day Seasonal Components with High Frequency Data
Authors: Beltratti Andrea , Morana Claudio 
Published: December 2003

We introduce a model for the analysis of intra‐day volatility based on unobserved components. The stochastic seasonal component is essential to model time‐varing intra‐day effects. The model is estimated with high frequency data for Deutsche mark–US dollar for 1993 and 1996. The model performs well in terms of coherence with the theoretical aggregation properties of GARCH models, it is effective in terms of both forecasting ability and describing reactions to macroeconomic news.(J.E.L.: C14, C53, F31).
Value‐at‐risk Trade‐off and Capital Allocation with Copulas
Authors: Cherubini Umberto , Luciano Elisa 
Published: December 2003

This paper uses copula functions to evaluate tail probabilities and market risk trade‐offs at a given confidence level, dropping the joint normality assumption on returns. Copulas enable one to represent distribution functions separating the marginal distributions from the association structure. We present an application to two stock market indices: for each market we recover the marginal probability distribution. We then calibrate copula functions and recover the joint distribution. The estimated copulas directly give the joint probabilities of extreme losses. Their level curves measure the trade‐off between losses over different desks. This trade‐off can be exploited for capital allocation and is shown to depend on fat tails.(J.E.L.: C14, G19, G29).
Hedging a Portfolio of Derivative Securities: A Simulation Approach
Authors: Tebaldi Claudio 
Published: December 2003

We illustrate a numerical simulation method to decompose a portfolio of derivative securities in a linear combination of dynamical risk factors. The price of the portfolio and its sensitivities are linear functions of these factors.The method generalizes the static hedging theory proposed by Madan and Milne (1994) and applies to a dynamically complete, arbitrage free market with purely Brownian fluctuating assets. The extension to a class of market models whose volatility dynamics shows long memory and scaling behaviour is discussed and shown to be possible.(J.E.L.: G12).
Credit Risk: Constructing the Basic Building Blocks
Authors: Hughston Lane P. , Turnbull Stuart M. 
Published: December 2003

This paper uses three basic results to address three problems. The first problem concerns the pricing of corporate bonds, when in the event of default the claim of the bond holders is on the principal of the bond plus accrued interest. The second concerns the pricing of revolver loans, and the third problem we address is the valuation of the collateral associated with a loan.(J.E.L.: G12, G13)
Fuzzy Value‐at‐risk: Accounting for Market Liquidity
Authors: Cherubini Umberto , Della Lunga Giovanni 
Published: December 2003

In this paper we present a value‐at‐risk measure which accounts for market liquidity. We show that taking into account market liquidity implies a decoupling of valuation of long and short positions. We present a pricing model, named fuzzy measure model, that yields different values for positions of different sign and that can be usefully exploited to account for liquidity risk. This methodology is well‐suited to price options when the distribution of the underlying asset is not known precisely, as in the case of implied options in corporate claims or real options. As an example, we apply our pricing technique to an option based model of value‐at‐risk, in line with the Merton and Perold approach, and we recover different value‐at‐risk figures for long and short positions.(J.E.L.: C00, D81, G12).