bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative competencies in infancy
Authors: Cordes Sara , Brannon Elizabeth M. 
Published: October 2008

Abstract We review recently published papers that have contributed to our understanding of how the preverbal infant represents number, area and time. We review evidence that infants rely on two distinct systems to represent number nonverbally and highlight the similarities in the ratio‐dependent discrimination of number, time and area. Contrary to earlier assertions that continuous dimensions are more salient (and thus more discriminable) to the infant than numerosity, we argue that the opposite conclusion is better supported by the data. The preverbal infant may be better able to extract numerosity than continuous variables from arrays of discrete items.
Corporate Governance and Cash Holdings: Listed New Economy versus Old Economy Firms
Authors: Chen Yenn‐Ru 
Published: October 2008

ABSTRACTManuscript Type: EmpiricalResearch Question/Issue: This study examines the impact of corporate governance on the cash‐holding policies of firms with different investment opportunities. It is difficult to determine the optimal level of cash holdings for “listed new economy” firms (firms in the computer, software, Internet, telecommunications, or networking industries), which require large amounts of capital for investment opportunities with high return potential. Unlike in “old economy” firms, for which investment opportunities are relatively limited, corporate governance in listed new economy firms may create shareholder protections that make investors willing to accept higher levels of corporate cash holdings.Research Findings/Results: By examining American Standard and Poor 1,500 companies, the evidence shows that CEO ownership and board independence affect the cash holdings in listed new economy and old economy firms differently. Specifically, higher managerial cash holdings tend to reduce cash holdings in old economy firms and higher board independence tend to increase cash holdings in listed new economy firms.Theoretical Implications: This study provides empirical support for the association between agency theory and cash theories. Given different firm characteristics, the impact of corporate governance on cash holdings verifies the implication of agency theory in explaining corporate cash policy.Practical Implications: While firms in new economy industries may be eager for more flexible governance codes in order to maintain the freedom of decision making, the evidence from this study suggests that establishing effective governance mechanisms may, in turn, effectively enlarge the degree of freedom for these firms to make timely business decisions.
Siblings’ Understanding of Learning Disability: A Longitudinal Study
Authors: Hames Annette 
Published: October 2008

Background  There is very little research on how and when siblings understand that they have a brother or sister with a learning disability. Research regarding young children’s understanding of intelligence, suggests that they may not develop a clear understanding of ability until about 7 years of age.Method  Through interviewing parents and then siblings, this study followed a group of young siblings for 12 years, from when they were pre‐verbal, until they were aged 12–14 years.Results  Siblings developed an early understanding of learning disability and had clear ideas about the future for them and for their brothers and sisters.Conclusion  Through their personal experiences, siblings are able to develop early understanding of the abstract concept of learning disability, are able to distinguish between disability and illness, and are able to think about the long‐term implications of learning disability both for themselves and for their brothers and sisters.
Antepartum and postpartum exposure to maternal depression: different effects on different adolescent outcomes
Authors: Hay Dale F. , Pawlby Susan , Waters Cerith S. , Sharp Deborah 
Published: October 2008

Background:  Postpartum depression (PPD) is considered a major public health problem that conveys risk to mothers and offspring. Yet PPD typically occurs in the context of a lifelong episodic illness, and its putative effects might derive from the child’s exposure to other episodes, in pregnancy or later childhood. The aim of the study is to test two hypotheses: (1) that the effects of PPD on adolescent outcomes are partly explained by antepartum depression (APD) and (2) that the effects of APD and PPD are both explained by later exposure to the mother’s depression.Method:  A random sample of 178 antenatal patients was drawn from two general medical practices in South London; 171 gave birth to live infants, and 150 (88%) were assessed at 3 months post partum, with 121 of their offspring (81%) assessed for emotional disorders (ED), disruptive behaviour disorders (DBD) and IQ, at 11 and 16 years of age.Results:  When APD and subsequent episodes of depression were taken into account, PPD had a significant effect on adolescent IQ, especially for boys, but did not predict psychopathology. ED and DBD in adolescence were predicted by the extent of exposure to maternal depression after 3 months post partum; a significant effect of APD on ED in girls was accounted for by later exposure to the mother’s illness. Mothers’ symptoms of anxiety, smoking and alcohol use in pregnancy did not predict adolescent outcomes, once maternal depression was taken into account.Conclusions:  Some effects attributed to mothers’ mental health problems in pregnancy or post partum may be mediated by cumulative exposure to maternal illness, probably reflecting genetic influence and gene–environment correlation. However, PPD has a direct effect on cognition. Clinicians should endeavour to identify women with depression in pregnancy (31% of this sample) and help them to manage their lifelong illness.
The dopamine receptor D4 7‐repeat allele and prenatal smoking in ADHD‐affected children and their unaffected siblings: no gene–environment interaction
Authors: Altink Marieke E. , Arias‐Vásquez Alejandro , Franke Barbara , Slaats –Willemse Dorine I.E. , Buschgens Cathelijne J.M. , Rommelse Nanda N.J. , Fliers Ellen A. , Anney Richard , Brookes Keeley‐Joanne , Chen Wai , Gill Michael , Mulligan Aisling , Sonuga‐Barke Edmund , Thompson Margaret , Sergeant Joseph A. , Faraone Stephen V. , Asherson Philip , Buitelaar Jan K. 
Published: October 2008

Background: The dopamine receptor D4 (DRD4) 7‐repeat allele and maternal smoking during pregnancy are both considered as risk factors in the aetiology of attention deficit hyperactivity disorder (ADHD), but few studies have been conducted on their interactive effects in causing ADHD. The purpose of this study is to examine the gene by environment (G×E) interaction of theDRD47‐repeat allele and smoking during pregnancy on ADHD and oppositional behavior in families from the International Multicenter ADHD Genetics project; and further, to test the hypothesis that the direction of effect of theDRD47‐repeat allele differs between ADHD affected and unaffected children.Methods: Linear mixed models were used to assess main and interactive effects of theDRD47‐repeat allele and smoking during pregnancy in 539 ADHD‐affected children and their 407 unaffected siblings, aged 6–17 years.Results: There was some evidence pointing to differential effects of theDRD47‐repeat allele on ADHD and oppositional symptoms in the affected (fewer symptoms) and unaffected children (increasing ADHD symptoms of teacher ratings). Affected children were more often exposed to prenatal smoking than unaffected children. There were limited main effects of prenatal smoking on severity of symptoms. Given the number of tests performed, no indication was found for G×E interactions.Conclusion: Despite the large sample size, no G×E interactions were found. The impact of theDRD47‐repeat allele might differ, depending on affected status and rater. This finding is discussed in terms of differences in the activity of the dopaminergic system and of different genes involved in rater‐specific behaviors.
The association of maternal chronic hypertension with perinatal death in male and female offspring: a record linkage study of 866 188 women
Authors: Zetterström K , Lindeberg SN , Haglund B , Hanson U 
Published: October 2008

Objective  The purpose of this study was to determine whether there is a difference, by gender, in perinatal mortality in chronically hypertensive women compared with normotensive women.Design  Population‐based prospective cohort study.Setting  Sweden.Population  A total of 866 188 women with singleton pregnancies registered in the Swedish Medical Birth Registry 1992–2004, of which 4749 were diagnosed with chronic hypertension.Methods  Multivariate logistic regression analysis was performed. In a first step, we adjusted for maternal characteristics and in a second step for mild and severe pre‐eclampsia, gestational diabetes, placental abruption and small for gestational age. An effect modification by gender was included in the model.Main outcome measures  Odds ratios (OR) for intrauterine death, neonatal death and post‐neonatal death with respect to gender of offspring.Results  The unadjusted OR of intrauterine death was 4.12 (95% CI: 2.84–5.96) and 1.29 (95% CI: 0.67–2.48) for male and female offspring, respectively, and of neonatal death, it was 3.45 (95% CI: 2.13–5.59) and 2.17 (95% CI: 1.08–4.35) for male and female offspring, respectively. After multivariate analysis, the OR of intrauterine death was 3.07 (95% CI: 2.12–4.46) and neonatal death was 2.99 (95% CI: 1.84–4.85) for male offspring. For female offspring, the OR of intrauterine death was 0.98 (95% CI: 0.51–1.89) and neonatal death was 1.88 (95% CI: 0.93–3.79).Conclusion  Mothers with chronic hypertension have an increased risk of perinatal mortality of their male offspring.
Can excess maternal mortality among women of foreign nationality be explained by suboptimal obstetric care?
Authors: Philibert M , Deneux‐Tharaux C , Bouvier‐Colle M‐H 
Published: October 2008

Objectives  To test the hypothesis that the risk of postpartum maternal death in France remains significantly higher for women of foreign nationality after individual characteristics are taken into account and to examine whether the quality of care received by the women who died differs according to nationality.Design  A national case–control study.Setting  Metropolitan France.Population  A total of 267 women who died of maternal death from 1996 to 2001 as cases and a representative sample (n = 13 186) of women who gave birth in 1998 as controls.Methods  Crude and adjusted odd ratios were calculated with multivariate logistic regression, and the quality of care for cases was compared according to nationality with chi‐square tests or Fisher’s exact tests.Main outcome measures  Odd ratio for postpartum maternal death associated with nationality and quality of care.Results  After taking individual characteristics into account, the risk of postpartum maternal death was twice as high for foreign women. The odds ratio was 5.5 (95% CI: 3.3–9.0) for women from sub‐Saharan Africa and 3.3 (95% CI: 1.7–6.5) for those from Asia, North and South America. There was no significant excess risk of postpartum maternal death for the other European and North Africa women. The risk of dying from hypertensive disorder or infection was four times higher for foreign women. Among women who died, care was more often considered not optimal for foreign women (78 versus 57%).Conclusions  The excess risk of postpartum maternal death persisted for foreign women after individual characteristics were taken into account and was especially important for some nationalities and for some causes of death, primarily hypertensive disorders. These results point to an immediate need to pay special attention to early enrolment in prenatal care, screening and prenatal management of hypertension, especially in women of sub‐Saharan African nationality.
Endometriosis and its coexistence with irritable bowel syndrome and pelvic inflammatory disease: findings from a national case–control study—Part 2
Authors: Seaman HE , Ballard KD , Wright JT , De Vries CS 
Published: October 2008

Objective  To investigate whether the increased chances of having a diagnosis of irritable bowel syndrome (IBS) and pelvic inflammatory disease (PID) in women with endometriosis is due to misdiagnosis or co‐morbidity.Design  A case–control study of women aged 15–55 years with endometriosis and matched controls.Setting  Data from the UK’s General Practice Research Database for the years 1992–2001.Sample  A total of 5540 women aged 15–55 years, diagnosed with endometriosis, each matched to four controls without endometriosis. The index date was defined as the date of diagnosis.Methods  Data were analysed to determine whether women with endometriosis were more likely to receive a diagnosis of PIDor IBS than women without endometriosis. Odds ratios were calculated for endometriosis associated with IBS and PID before and after the index date.Main outcome measures  Diagnosis of IBS or PID before and after the index date.Results  Compared with the controls, women with endometriosis were 3.5 times more likely to have received a diagnosis of IBS (OR 3.5 [95% CI: 3.1–3.9]). Even after women had been diagnosed with endometriosis, they were still two and a half times more likely to receive a new diagnosis of IBS when compared with the controls (OR 2.5 [95% CI: 2.2–2.8]). Similarly, women with endometriosis were more likely than those without endometriosis to have been treated for PID both before (OR 5.9 [95% CI: 5.1–6.9]) and after (OR 3.8 [95% CI: 3.1–4.6]) being diagnosed with endometriosis.Conclusions  Women with endometriosis are more likely to be diagnosed with IBS and PID than controls, even after a definitive diagnosis of endometriosis has been reached.
Influence of mode of delivery on neonatal mortality in the second twin, at and before term
Authors: Herbst A , Källén K 
Published: October 2008

Design  To study the association between mode of delivery and neonatal mortality in second twins. To study the association between caesarean delivery and mortality with minimum bias of the indication for the operation, we wanted to compare the outcome of second twins delivered by caesarean due to breech presentation of the sibling with vaginally delivered second twins in uncomplicated pregnancies.Setting  Sweden, 1980–2004Population  Twins born during 1980–2004 were identified from the Swedish Medical Birth Registry. Twin pairs delivered by caesarean due to breech presentation of the first twin, and vaginally delivered twins with the first twin in cephalic presentation were included. Pregnancies with antepartum complications were excluded.Methods  Odds ratios and 95% CI were calculated using multiple logistic regression analyses, adjusting for year of birth, maternal age, parity and gestational age.Main outcome measures  Neonatal mortality.Results  Compared with second‐born twins delivered vaginally, second‐born twins delivered by caesarean (for breech presentation of the sibling) had a lower risk of neonatal death (adjusted OR 0.40; 95% CI 0.19–0.83). The decreased risk after caesarean delivery was significant for births before 34 weeks (2.1 versus 9.0%; adjusted OR 0.40; 95% CI 0.17–0.95). After 34 weeks, neonatal mortality was low in both groups (0.1 and 0.2%, respectively), and the difference was not statistically significant (adjusted OR 0.42; 95% CI 0.10–1.79).Conclusions  Neonatal mortality is lower for the second twin after caesarean delivery at birth before 34 weeks. At term, mortality is low irrespective of delivery mode.
Retracted: Differential effects of 24‐hydroxycholesterol and 27‐hydroxycholesterol on tyrosine hydroxylase and α‐synuclein in human neuroblastoma SH‐SY5Y cells
Authors: Rantham Prabhakara Jaya Prasanthi , Feist Gwen , Thomasson Sarah , Thompson Alex , Schommer Eric , Ghribi Othman 
Published: October 2008

AbstractEvidence suggests that environmental and dietary factors may contribute to the pathogenesis of Parkinson’s disease (PD). High dietary intake of cholesterol is such a factor that has been shown to increase or decrease the risk of PD. However, because circulating cholesterol does not cross the blood–brain barrier, the mechanisms linking dietary cholesterol to the pathogenesis of PD remain to be understood. In contrast to cholesterol, the oxidized cholesterol metabolites (oxysterols), 24S‐hydroxycholesterol (24‐OHC) and 27‐hydroxycholesterol (27‐OHC), can cross the blood–brain barrier and may place the brain at risk of degeneration. In this study, we incubated the human neuroblastoma SH‐SY5Y cells for 24 h with 24‐OHC, 27‐OHC, or a mixture of 24‐OHC plus 27‐OHC, and have determined effects on tyrosine hydroxylase (the rate‐limiting enzyme in dopamine synthesis) levels, α‐synuclein levels, and apoptosis. We demonstrate that while 24‐OHC increases the levels of tyrosine hydroxylase, 27‐OHC increases levels of α‐synuclein, and induces apoptosis. Our findings show for the first time that oxysterols trigger changes in levels of proteins that are associated with the pathogenesis of PD. As steady state levels of 24‐OHC and 27‐OHC are tightly regulated in the brain, disturbances in these levels may contribute to the pathogenesis of PD.
Secretory vesicle rebound hyperacidification and increased quantal size resulting from prolonged methamphetamine exposure
Authors: Markov Dmitriy , Mosharov Eugene V. , Setlik Wanda , Gershon Michael D. , Sulzer David 
Published: October 2008

AbstractAcute exposure to amphetamines (AMPHs) collapses secretory vesicle pH gradients, which increases cytosolic catecholamine levels while decreasing the quantal size of catecholamine release during fusion events. AMPH and methamphetamine (METH), however, are retained in tissues over long durations. We used optical and electron microscopic probes to measure the effects of long‐term METH exposure on secretory vesicle pH, and amperometry and intracellular patch electrochemistry to observe the effects on neurosecretion and cytosolic catecholamines in cultured rat chromaffin cells. In contrast to acute METH effects, exposure to the drug for 6–48 h at 10 μM and higher concentrations produced a concentration‐dependent rebound hyperacidification of secretory vesicles. At 5–10 μM levels, prolonged METH increased the quantal size and reinstated exocytotic catecholamine release, although very high (> 100 μM) levels of the drug, while continuing to produce rebound hyperacidification, did not increase quantal size. Secretory vesicle rebound hyperacidification was temperature dependent with optimal response at ∼37°C, was not blocked by the transcription inhibitor, puromycin, and appears to be a general compensatory response to prolonged exposure with membranophilic weak bases, including AMPHs, methylphenidate, cocaine, and ammonia. Thus, under some conditions of prolonged exposure, AMPHs and other weak bases can enhance, rather than deplete, the vesicular release of catecholamines via a compensatory response resulting in vesicle acidification.
A long‐term study (1949–2005) of experimental introductions to an island; freshwater amphipods (Crustacea) in the Isle of Man (British Isles)
Authors: MacNeil Calum , Dick Jaimie T. A. , Gell Fiona R. , Selman Richard , Lenartowicz Paul , Hynes H. B. Noel 
Published: October 2008

ABSTRACTAim  Using data from field introduction experiments with Gammarus spp. conducted in the rivers of a small island, commencing in 1949, with resampling in the 60s, 70s, 80s, 90s and finally in 2005, we aimed to examine the long‐term interaction of the native freshwater amphipod Gammarus duebeni celticus with the introduced G. pulex. Using physico‐chemical data from a 2005 island‐wide survey, we also aimed to find what environmental factors could influence the distribution of the two species.Location  The Isle of Man, British Isles.Methods  We used species distribution data from 10 river sites from a field introduction study in 1949–69, resampling of these sites in 1974/5, 1988, 1995 and 2005. We sampled a further 82 sites in 2005, where physico‐chemical characteristics of each site were obtained. ANOVA was used to ascertain significant differences in environmental variables between native and introduced amphipod assemblages. Multiple discriminant analysis was used to relate Gammarus distribution to environmental gradients in rivers.Results  Field introductions of G. pulex into previously G. d. celticus dominated sites failed, despite the large propagule pressure in terms of numbers of individuals released and repeated introductions. The island‐wide survey revealed that G. d. celticus was found in areas of higher water quality than G. pulex. Sites where the two species co‐occurred also tended to be of lower water quality than native only sites. Continuing metal pollution from past mining activity may be a major factor excluding all amphipods from many rivers. The North American amphipod Crangonyx pseudogracilis, which was first discovered on the Isle of Man in one river site in 1995, was found in a further five sites.Main conclusions  This ecological experiment, through long‐term monitoring, thus continues to elucidate factors influencing the distributions of introduced and native species. Under some physicochemical regimes, G. d. celticus is able to withstand its usual displacement by G. pulex, whereas increased river pollution could promote replacement of the native by the introduced species.
Suicide in Older Adults in Long‐Term Care: 1990 to 2005
Authors: Mezuk Briana , Prescott Marta R. , Tardiff Kenneth , Vlahov David , Galea Sandro 
Published: October 2008

OBJECTIVES: To describe the characteristics associated with suicide in older persons residing in long‐term care (LTC) facilities, to compare the characteristics of suicide cases in LTC with those of cases in the community, and to evaluate trends in suicide in these settings over the past 15 years.SETTING: The New York City (NYC) Office of the Chief Medical Examiner (OCME).PARTICIPANTS: Suicide deaths in NYC from 1990 to 2005.MEASUREMENTS: Location and method of suicide death reported by OCME.METHODS: Suicides in older persons in LTC and community‐dwelling older adults were compared in terms of demographic characteristics and method used. Trends in suicide rate ratios (RRs) were examined using zero‐inflated Poisson regression.RESULTS: Over the study period, there were 1,771 suicides among NYC residents aged 60 and older: 47 in LTC and 1,724 in the community. Cases in LTC tended to be older (P<.02) but did not differ from community cases in terms of race or sex. Suicides in LTC were significantly less likely (RR=0.05, P<.002) to be due to firearms and 2.49 times as likely to be due to a long fall (P<.002) as community cases. Over the 15‐year period, there was a significant decrease in the relative rate of suicide in community‐dwelling adults (RR=0.97, P<.001) but no change in residents of LTC (RR=1.05, P<.17).CONCLUSIONS: Suicide risk in community‐dwelling older adults has declined over the past 15 years but has not changed in LTC facilities. This suggests that prevention efforts may not be reaching this population effectively.