bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intraspecific variation in ejaculate traits of the northern watersnake (Nerodia sipedon)
Authors: Schulte‐Hostedde A. I. , Montgomerie R. 
Published: May 2006

AbstractSperm competition occurs when the sperm of more than one male compete to fertilize the eggs of a female. In reptiles, sperm competition is particularly prevalent and is an important agent of sexual selection in males. Spermatogenesis in reptiles can be energetically expensive, suggesting that there may be costs to producing high‐quality ejaculates. The northern watersnake Nerodia sipedon has a mating system characterized by aggregations in which a single female mates with multiple males, resulting in high levels of multiple paternities. Under these circumstances sperm competition is likely important, and selection should favour sperm and ejaculate traits that enhance a male's reproductive success. In this study, we examined intraspecific variation in ejaculate quality (sperm length, motility, sperm density, spermactocrit) in male watersnakes and determined whether ejaculate traits varied with body size and condition, using both size‐corrected mass and haematocrit as indices of condition. We found large variation among males in all these traits, except for sperm length. Although there was significant variation in sperm length among males, the majority of variation in sperm length occurred within rather than among individuals. Males with high haematocrit had sperm that were less variable with respect to length, and large males produced ejaculates that were less concentrated with respect to sperm than small males. The lack of condition dependence of most ejaculate traits is consistent with previous studies that indicate that male reproductive effort in this species is generally not energy limited, perhaps because of opportunistic foraging during the mating season.
Density, habitat use and activity patterns of ocelots (Leopardus pardalis) in the Atlantic Forest of Misiones, Argentina
Authors: Di Bitetti M. S. , Paviolo A. , De Angelo C. 
Published: May 2006

AbstractCamera‐trap surveys were carried out at two different sites within the Atlantic Forest of Misiones province, Argentina, to study the density, habitat use and activity patterns of ocelots. At Urugua‐í Provincial Park, 17 different individuals were captured (nine females, six males, two of unknown sex) during a 3‐month‐long survey (34 camera stations, 1409 trap days). At Iguazú National Park, 34 different individuals were trapped (20 adult females, nine adult males, two subadult females and three of unknown sex) during the survey (39 sampling stations, 1631 trap days). Population density estimates (±se) for Urugua‐í, in an area of between 150 and 259 km2 (depending on the buffer used to estimate the area effectively sampled), range from 7.7±1.4 to 13.4±2.6 individuals × 100 km−2, whereas at Iguazú, in an area of between 275 and 428 km2, a population density of between 12.8±2.7 and 20.0±4.2 individuals × 100 km−2 was estimated. Minimum observed range estimates for individuals with >3 capture sites range from 3.19 to 37.09 km2 for four males and from 4.17 to 7.11 km2 for three females, but underestimate the true home range size. Ocelots were captured more frequently along old roads than on new trails opened with machetes. Ocelots were captured more frequently at night than during the day and reduce their use of roads and trails during the week previous to and during full moon nights, a behavior previously reported for Amazonian ocelots. Population density estimates for ocelots in the Upper Paraná Atlantic Forest ecoregion are lower than those at other neotropical sites. The whole Green Corridor contains a population of about 1280 individuals. This estimate should bring our attention to the larger cats (pumas and jaguars) that live at lower population densities because the future of their local populations is compromised if protected areas are not urgently created and properly managed.
Stable isotope evidence (δ13C, δ18O) for winter feeding on seaweed by Neolithic sheep of Scotland
Authors: Balasse M. , Tresset A. , Ambrose S. H. 
Published: May 2006

AbstractThe antiquity of the use of seaweed to feed domestic animals was investigated through carbon (δ13C) and oxygen (δ18O) isotope analysis of tooth enamel bioapatite. The analysis was performed on sheep and cattle teeth from two Neolithic sites in Orkney (Scotland). At the Knap of Howar, c. 3600 bc, carbon isotopes reflect grazing on terrestrial plants throughout the year for both sheep and cattle, with no contribution of seaweed to their diet. At the Holm of Papa Westray North (HPWN), c. 3000 bc, significant contribution of seaweed to the sheep diet during winter is indicated by bioapatite δ13C values as high as −5.7‰, far outside of the range of values expected for the feeding on terrestrial C3 plants, and δ18O values higher than expected during winter, possibly caused by ingestion of oceanic water with seaweed. Ingestion of seaweed by sheep at HPWN might have been necessitated by severe reduction of pastures during winter. Results suggest that sheep ingested fresh seaweed rather than dry fodder, perhaps directly on the shore as sheep do nowadays on North Ronaldsay. A significant difference between the two populations is the exclusive reliance on seaweed by the North Ronaldsay sheep, which have developed physiological adaptations to this diet. Contribution of seaweed to the sheep winter diet at HPWN might have been a first step towards this adaptation.
Growth and age determination of African savanna elephants
Authors: Shrader A. M. , Ferreira S. M. , McElveen M. E. , Lee P. C. , Moss C. J. , Van Aarde R.J. 
Published: May 2006

AbstractUnderstanding the population dynamics of savanna elephants depends on estimating population parameters such as the age at first reproduction, calving interval and age‐specific survival rates. The generation of these parameters, however, relies on the ability to accurately determine the age of individuals, but a reliable age estimation technique for free‐ranging elephants is presently not available. Shoulder heights of elephants were measured in 10 populations in five countries across southern and eastern Africa. Data included shoulder height measurements from two populations where the age of each individual was known (i.e. Addo Elephant National Park, South Africa and Amboseli National Park, Kenya). From the known‐age data, Von Bertalanffy growth functions were constructed for both male and female elephants. Savanna elephants were found to attain similar asymptotic shoulder heights in the 10 populations, while individuals in the two known‐age populations grew at the same rate. The Von Bertalanffy growth curves allowed for the accurate age estimation of females up to 15 years of age and males up to 36 years of age. The results indicate that shoulder height can serve as an indicator of chronological age for elephants below 15 years of age for females and 36 years of age for males. Ages derived from these growth curves can then be used to generate age‐specific population variables, which will help assess the demographic status of savanna elephant populations across Africa.
Probability‐independent and ‐dependent ERPs reflecting visual change detection
Authors: Kimura Motohiro , Katayama Jun'ichi , Murohashi Harumitsu 
Published: May 2006

AbstractIn ERP studies, two posterior components with different polarities have been identified as ERP correlates of visual change detection. To compare these components in terms of sensitivity to the preceding stimulus sequence, two peripheral stimuli of different colors (red and blue) were presented with equal (50:50) or different probabilities (20:80 or 80:20), while 12 participants performed shape discrimination at a central location. A posterior positivity at around 90–140 ms was observed with similar amplitude to all stimuli immediately preceded by a different stimulus. In contrast, a posterior negativity at around 140–180 ms was observed to increase in amplitude with increasing number of preceding different stimuli. These results suggest the existence of probability‐independent and ‐dependent change processing in the human visual system. The functional significance is discussed in terms of memory‐based comparison and stimulus‐specific refractoriness.
Fast optical imaging of frontal cortex during active and passive oddball tasks
Authors: Low Kathy A. , Leaver Echo , Kramer Arthur F. , Fabiani Monica , Gratton Gabriele 
Published: May 2006

AbstractThis study used the high spatial and temporal resolution of the event‐related optical signal (EROS) to investigate the timing of neuronal activity in frontal cortex during auditory target detection and passive oddball tasks. Activation in right middle frontal gyrus (MFG) peaked approximately 350 ms following rare target tones. This corresponded closely to the latency of the simultaneously recorded electrical P3 component. In addition, we found activation in left lateral MFG peaking at approximately 130 ms following tone onset for conditions that may have required response inhibition. These results correspond with activation patterns observed in similar fMRI studies, but provide temporal tags for the activated locations. These data may help bridge the gap between electrophysiological and hemodynamic measures of target detection and contribute to our understanding of the spatiotemporal dynamics of brain activity during target processing.
Habituation of auditory evoked potentials in intracranial and extracranial recordings
Authors: Rosburg Timm , Trautner Peter , Boutros Nashaat N. , Korzyukov Oleg A. , Schaller Carlo , Elger Christian Erich , Kurthen Martin 
Published: May 2006

AbstractEffects of stimulus repetition are investigated in short‐term habituation experiments. In these experiments, trains of stimuli are applied with longer intervals of no stimulation between the trains. In scalp recordings, an amplitude and latency decrease of the auditory N100 is usually observed at the beginning of the train. This contrasts to a recent finding with intracranial recordings, exhibiting an effect on N100 amplitude, but not on its latency. In the current study, P50 and N100 were simultaneously recorded intra‐ and extracranially in epilepsy patients. The amplitudes of P50 and N100 decreased in both recordings, whereas the P50 latency was not significantly affected. A latency decrease was revealed for the extracranially recorded N100, but not for the intracranial N100. This dissociation between the intracranial and scalp recordings might be explained by a different sensitivity of the two measurements for N100 generators.
When does size not matter? Effects of stimulus size on affective modulation
Authors: De Cesarei Andrea , Codispoti Maurizio 
Published: May 2006

AbstractMotivationally relevant stimuli have been shown to receive prioritized processing compared to neutral stimuli at distinct processing stages. This effect has been related to the evolutionary importance of rapidly detecting dangers and potential rewards and has been shown to be modulated by the distance between an organism and a faced stimulus. Similarly, recent studies showed degrees of emotional modulation of autonomic responses and subjective arousal ratings depending on stimulus size. In the present study, affective modulation of pictures presented in different sizes was investigated by measuring event‐related potentials during a two‐choice categorization task. Results showed significant emotional modulation across all sizes at both earlier and later stages of processing. Moreover, affective modulation of earlier processes was reduced in smaller compared to larger sizes, whereas no changes in affective modulation were observed at later stages.
Task‐dependent exogenous cuing effects depend on cue modality
Authors: Van der Lubbe Robh.J. , Havik Maarten M. , Bekker Evelijne M. , Postma Albert 
Published: May 2006

AbstractTask‐dependent exogenous cuing effects on reaction time in detection and discrimination tasks have been ascribed to delayed withdrawal of attention in discrimination tasks. Alternatively, these differences may be due to cue‐induced response inhibition in detection tasks. Unimodal and crossmodal versions of the Posner paradigm were examined with short cue–target intervals. Targets above or below fixation required either detection or discrimination responses. Cuing effects were determined for the target‐elicited P1 component and for the lateralized readiness potential (LRP). Task‐dependent cuing effects on reaction time were found in the unimodal but not in the crossmodal version, but not for the P1 component. The LRP data indicated that inhibition of return in the unimodal detection task had a premotoric locus. These findings suggest that inhibition in the unimodal detection task resulted from speeded motor inhibition triggered by the visual cue.
An event‐related potential study of supramodal attentional control and crossmodal attention effects
Authors: Green Jessica J. , McDonald John J. 
Published: May 2006

AbstractWe conducted two audiovisual experiments to determine whether event‐related potential (ERP) components elicited by attention‐directing cues reflect supramodal attentional control. Symbolic visual cues were used to direct attention prior to auditory targets in Experiment 1, and symbolic auditory cues were used to direct attention prior to visual targets in Experiment 2. Different patterns of cue ERPs were found in the two experiments. A frontal negativity called the ADAN was absent in Experiment 2, which indicates that this component does not reflect supramodal attentional control. A posterior positivity called the LDAP was observed in both experiments but was focused more posteriorly over the occipital scalp in Experiment 2. This component appears to reflect multiple processes, including visual processes involved in location marking and target preparation as well as supramodal processes involved in attentional control.
Preattentive timing of empty intervals is from marker offset to onset
Authors: Tse Chun‐Yu , Penney Trevor B. 
Published: May 2006

AbstractThe internal marker hypothesis explains the superior timing performance for empty intervals over filled intervals by assuming that timing an empty interval starts from the offset of the first marker stimulus and stops at the onset of the second marker stimulus. Other models suggest that timing an empty interval is from first marker onset to second marker onset. We used an electrophysiological measure of preattentive change detection, the mismatch negativity (MMN), to examine processing of empty intervals. Participants watched a silent movie while a stream of auditory stimuli demarcating empty intervals was presented in the background. Most intervals were of the same duration (standards), but shorter intervals (deviants) were presented occasionally also. The pattern of MMN amplitudes obtained across five deviant conditions indicated that preattentive timing of empty intervals occurred from marker offset to onset.
Late miscarriage and preterm birth after treatment with clindamycin: a randomised consent design study according to Zelen
Authors: Larsson P‐G , Fåhraeus L , Carlsson B , Jakobsson T , Forsum U ,   the premature study group of the Southeast Health Care Region of Sweden
Published: May 2006

Objective  To screen for bacterial vaginosis (BV) and to investigate the effect of treatment with vaginal clindamycin in order to observe the effect on late miscarriage and delivery prior to 37 completed weeks (primary outcome).Design  Randomised consent design for clinical trials according to Zelen.Setting  Southeast region of Sweden.Population  A total of 9025 women were screened in early pregnancy.Methods  A total of 819 women with a Nugent score of 6 and above were considered to have BV and treated according to Zelen allocation. The incidence of late miscarriage and spontaneous (noniatrogenic) preterm birth was assessed.Main outcome measures  Late miscarriage and spontaneous preterm delivery before 37 weeks.Results  Therapy with vaginal clindamycin had no significant impact on the incidence of spontaneous preterm delivery prior to 37 completed weeks; OR 0.90, 95% CI 0.40–2.02 (primary outcome variable). However, only 1 of 11 women in the treatment group versus 5 of 12 in the control group delivered prior to 33 completed weeks; OR 0.14, 95% CI 0.02–0.95. Treatment was associated with 32 days longer gestation for the 23 participants who had late miscarriage or spontaneous preterm birth (P= 0.024, Mann–Whitney U test) and significantly fewer infants had a birthweight below 2500 g (secondary outcome). A follow up of infants born preterm 4 years postnatally indicated that extending gestational age did not increase the number of sequelae.Conclusions  Clindamycin vaginal cream therapy was associated with significantly prolonged gestation and reduced cost of neonatal care in women with BV. Early screening for BV and treatment with clindamycin saved approximately €27 per woman.
Regimens of misoprostol with mifepristone for early medical abortion: a randomised trial
Authors: Shannon C , Wiebe E , Jacot F , Guilbert E , Dunn S , Sheldon WR , Winikoff B 
Published: May 2006

Objective  To compare the efficacy, adverse effects and acceptability of the three most common misoprostol regimens used with mifepristone for medical abortion.Design  Randomised nonblinded trial.Setting  Three clinics associated with major research universities in Canada; two in major urban areas and one in a periurban area.Population  Women of reproductive age.Methods  Consenting women presenting for abortion services with gestations less than 56 days and who met inclusion criteria were given 200 mg mifepristone orally and then randomised into three misoprostol study groups: (group I) 400 micrograms of oral misoprostol, (group II) 600 micrograms of oral misoprostol, and (group III) 800 micrograms of vaginal misoprostol. Misoprostol was self‐administered at home 24–48 hours following mifepristone, and participants were instructed to take a second similar misoprostol dose at 24 hours after the initial dose if bleeding was less than a normal menstrual period.Main outcome measures  Successful abortion without surgery was 94.1%, with no significant differences across the three study groups (94.7% in group I, 93.4% in group II, and 94.3% in group III; P= 0.975).Results  Efficacy and adverse effects did not differ significantly across the three study groups. Pain increased significantly across the study and the gestational age groups and was associated with lower acceptability.Conclusions  There appears to be a range of safe and effective options for early medical abortion with mifepristone including a choice between oral and vaginal administration of misoprostol.
Antenatal fear of childbirth and its association with subsequent caesarean section and experience of childbirth
Authors: Waldenström U , Hildingsson I , Ryding EL 
Published: May 2006

Objective  To investigate the prevalence of fear of childbirth in a nationwide sample and its association with subsequent rates of caesarean section and overall experience of childbirth.Design  A prospective study using between‐group comparisons.Setting  About 600 antenatal clinics in Sweden.Sample  A total of 2662 women recruited at their first visit to an antenatal clinic during three predetermined weeks spread over 1 year.Methods  Postal questionnaires at 16 weeks of gestation (mean) and 2 months postpartum. Women with fear of childbirth, defined as ‘very negative’ feelings when thinking about the delivery in second trimester and/or having undergone counselling because of fear of childbirth later in pregnancy, were compared with those in the reference group without these characteristics.Main outcome measures  Elective and emergency caesarean section and overall childbirth experience.Results  In total 97 women (3.6%) had very negative feelings and about half of them subsequently underwent counselling. In addition, 193 women (7.2%) who initially had more positive feelings underwent counselling later in pregnancy. In women who underwent counselling, fear of childbirth was associated with a three to six times higher rate of elective caesarean sections but not with higher rates of emergency caesarean section or negative childbirth experience. Very negative feelings without counselling were not associated with an increased caesarean section rate but were associated with a negative birth experience.Conclusions  At least 10% of pregnant women in Sweden suffer from fear of childbirth. Fear of childbirth in combination with counselling may increase the rate of elective caesarean sections, whereas fear without treatment may have a negative impact on the subsequent experience of childbirth.
Routine ultrasound examination at 12 or 18 gestational weeks for prenatal detection of major congenital heart malformations? A randomised controlled trial comprising 36 299 fetuses
Authors: Westin M , Saltvedt S , Bergman G , Kublickas M , Almström H , Grunewald C , Valentin L 
Published: May 2006

Objective  To compare the rate of prenatal diagnosis of heart malformations between two policies of screening for heart malformations.Design  Randomised controlled trial.Setting  Six university hospitals, two district general hospitals.Sample  A total of 39 572 unselected pregnancies randomised to either policy.Methods  The 12‐week policy implied one routine scan at 12 weeks including measurement of nuchal translucency (NT), and the 18‐week policy implied one routine scan at 18 weeks. Fetal anatomy was scrutinised using the same check‐list in both groups, and in both groups, indications for fetal echocardiography were ultrasound findings of any fetal anomaly, including abnormal four‐chamber view, or other risk factors for heart malformation. In the 12‐week scan group, NT ≥3.5 mm was also an indication for fetal echocardiography.Main outcome measure  Prenatal diagnosis of major congenital heart malformation.Results  In the 12‐week scan group, 7 (11%) of 61 major heart malformations were prenatally diagnosed versus 9 (15%) of 60 in the 18‐week scan group (P= 0.60). In four (6.6%) women in the 12‐week scan group, the routine scan was the starting point for investigations resulting in a prenatal diagnosis versus in 9 (15%) women in the 18‐week scan group (P= 0.15). The diagnosis was made ≤22 weeks in 5% (3/61) of the cases in the 12‐week scan group versus in 15% (9/60) in the 18‐week scan group (P= 0.08).Conclusions  The prenatal detection rate of major heart malformations was low with both policies. The 18‐week scan policy seemed to be superior to the 12‐week scan policy, although the differences in prenatal detection rates were not statistically significant.