bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fe xiii emission lines in active region spectra obtained with the Solar Extreme-Ultraviolet Research Telescope and Spectrograph
Authors: Keenan F. P. , Jess D. B. , Aggarwal K. M. , Thomas R. J. , Brosius J. W. , Davila J. M. 
Published: February 2007

Abstract
Recent fully relativistic calculations of radiative rates and electron impact excitation cross-sections for Fe xiii are used to generate emission-line ratios involving 3s23p2–3s3p3 and 3s23p2–3s23p3d transitions in the 170–225 and 235–450 Å wavelength ranges covered by the Solar Extreme-Ultraviolet Research Telescope and Spectrograph (SERTS). A comparison of these line ratios with SERTS active region observations from rocket flights in 1989 and 1995 reveals generally very good agreement between theory and experiment. Several new Fe xiii emission features are identified, at wavelengths of 203.79, 259.94, 288.56 and 290.81 Å. However, major discrepancies between theory and observation remain for several Fe xiii transitions, as previously found by Landi and others, which cannot be explained by blending. Errors in the adopted atomic data appear to be the most likely explanation, in particular for transitions which have 3s23p3d 1D2 as their upper level. The most useful Fe xiii electron-density diagnostics in the SERTS spectral regions are assessed, in terms of the line pairs involved being (i) apparently free of atomic physics problems and blends, (ii) close in wavelength to reduce the effects of possible errors in the instrumental intensity calibration, and (iii) very sensitive to changes in Ne over the range 108–1011 cm−3. It is concluded that the ratios which best satisfy these conditions are 200.03/202.04 and 203.17/202.04 for the 170–225 Å wavelength region, and 348.18/320.80, 348.18/368.16, 359.64/348.18 and 359.83/368.16 for 235–450 Å.
Effects of environmental factors on discharge and germination of ascospores of Venturia nashicola
Authors: Lian S. , Li B.‐H. , Dong X.‐L. , Li B.‐D. , Xu X.‐M. 
Published: February 2007

Experiments were conducted under controlled environmental conditions to study the effects of temperature, duration of wetness, relative humidity (RH) and light on the discharge and germination of ascospores of Venturia nashicola, the causal agent of pear scab in China. Discharge of ascospores from pseudothecia required free water or 100% RH. A period of soaking in water as short as 10 s was sufficient to initiate the discharge of ascospores. Temperatures from 10 to 30°C did not significantly affect the temporal trend of ascospore discharge. A greater proportion of ascospores was discharged under light than in the dark. However, a period of light as short as 10 min, either during the initial wetting of pseudothecia or interrupting the darkness, was sufficient to reduce the inhibitory effect of darkness on ascospore discharge. Ascospores were discharged within 10 min after pseudothecia were wetted and most ascospores (c. 80%) were discharged within the first hour. The temporal pattern of ascospore discharge could be well described by a logistic model, which estimated that 50% of ascospores were discharged within half an hour of wetting. Ascospores germinated over a wide range of temperatures from 5 to 30°C, with an optimum at c. 20°C. Temporal dynamics of ascospore germination at six temperatures (5, 10, 15, 20, 25 and 30°C) were satisfactorily described by logistic models.
Environmental Manipulation to Avoid a Unique Predator: Drinking Hole Excavation in the Agile Wallaby, Macropus agilis
Authors: Sean Doody J. , Sims Rachel A. , Letnic Mike 
Published: February 2007

AbstractThe simplest way of avoiding an ambush predator is to entirely avoid the habitat in which it hunts. However, this strategy requires that the prey species find alternative, risk‐free sources of essential resources. Herein we describe a novel strategy used by agile wallabies (Macropus agilis) to avoid saltwater crocodile (Crocodylus porosus) predation: the creation of risk‐free sites to obtain water. We studied the anti‐predator behaviour of agile wallabies for 3 yr during the dry season along the Daly River, Northern Territory, Australia. Wallabies excavated holes in the sand 0.5–18.0 m from the water's edge, and preferred to drink from these holes over drinking from the river. We determined a hierarchy of preferred drinking‐site options for the wallabies: non‐river sites: springs, puddles, excavated holes; and river sites: sites with cover, shallow water sites and deep water sites. Drinking holes were twice as far from the water's edge in a river stretch with high crocodile density (2/km) than those in a stretch with low crocodile density (0.08/km). However, site differences could also be explained by river bank morphology. Collectively, our findings indicate that agile wallabies excavate drinking holes to avoid crocodile predation. We contend that this behaviour represents environmental manipulation specifically to alter the risk associated with obtaining a key resource.
Communal Nesting in Asocial Abert's Squirrels: the Role of Social Thermoregulation and Breeding Strategy
Authors: Edelman Andrew J. , Koprowski John L. 
Published: February 2007

AbstractThe social thermoregulation hypothesis states that endothermic species will communally nest to reduce energy expenditures on thermoregulation. The hypothesis predicts that the frequency of communal nesting should increase with decreasing ambient temperature. The potential costs of communal nesting (e.g., increased predation risk, resource competition, cuckoldry, parasite/disease transmission, or infanticide) could decrease the frequency of communal nesting especially for asocial breeding females with dependent offspring. We examined the effects of ambient temperature and seasonal reproductive activities on the probability of communal nesting in Abert's squirrels (Sciurus aberti) in the Pinaleño Mountains, Arizona. Most squirrels nested consistently with the same partner in mixed‐sex pairs. The proportion of individuals engaging in communal nesting increased with decreasing ambient temperature as predicted by the social thermoregulation hypothesis. The onset of the breeding season greatly reduced the proportion of individuals communally nesting. The negative relationship between ambient temperature and communal nesting supports the use of communal nesting in Abert's squirrels as a mechanism to reduce thermoregulatory costs during cold conditions. The abrupt drop in the frequency of communal nesting during the breeding season is likely due to female abandonment of this behavior. By avoiding communally nesting during the breeding season, females may prevent males from mating with them outside of mating chases, reduce resource competition, and protect offspring from infanticide, diseases, and parasites. Males may gain additional fitness benefits from nesting with females because familiarity with females increases dominance rank in mating activities.
Phenotypic Plasticity and the Ecotypic Differentiation of Aggressive Behavior in Threespine Stickleback
Authors: Scotti Melissa‐Ann L. , Foster Susan A. 
Published: February 2007

AbstractThe threespine stickleback fish,Gasterosteus aculeatus, has undergone a remarkable postglacial adaptive radiation in which an ancient oceanic ancestor has given rise to uncountable freshwater populations. The radiation is characterized by repeated, independent evolution of similar derived phenotypes under similar environmental conditions. A common pattern of divergence is caused by differences in habitat that favor morphological and behavioral features that enhance efficiency of feeding on plankton (limnetic ecotypes) vs. those that enhance efficiency of feeding on benthic invertebrates (benthic ecotypes). These two ecotypes exhibit consistently different patterns of courtship and of foraging and cannibalistic behavior (divergent behavioral syndromes). Here, we demonstrate that there also exist differences in aggression toward conspecifics that are likely to be characteristic of the ecotypes. We report differences in patterns of aggression toward rivals between the ecotypes and offer evidence of differences in the patterns of phenotypic plasticity (norms of reaction) for these traits across population types, and of differences in the incorporation of aggressive elements of behavior in courtship. These data support an earlier suggestion that differences in aggressive tendencies could have facilitated assortative mating between the four benthic–limnetic species pairs found in British Columbia lakes, and they demonstrate the need to evaluate divergent behavioral phenotypes in this radiation as phenotypic norms of reaction rather than as fixed traits.
Effects of Exogenous ACTH during Oestrus on Early Embryo Development and Oviductal Transport in the Sow
Authors: Brandt Y , Madej A , Rodríguez‐Martínez H , Einarsson S 
Published: February 2007

ContentsThis study was conducted to assess the effects of ACTH injections on the early development of embryos and their transportation to the uterus. Fifteen sows were monitored for ovulation using transrectal ultrasonography during the first two oestrous periods after weaning. The sows were randomly divided into a control group (C group, n = 8) and an ACTH‐treated group (ACTH group, n = 7), and were all surgically fitted with intra‐jugular catheters. From the onset of the second standing oestrus after weaning, the sows were injected (NaCl/synthetic ACTH) every 4 h. Blood samples were collected immediately before and 45 min after each injection. All sows were inseminated once 10–33 h before ovulation in their second oestrus after weaning. At 48 (n = 4) or 60 (n = 11) h after ovulation during their second oestrus, the sows were killed and the embryos retrieved from the oviduct and uterus. The embryos were counted and compared with the number of corpora lutea, cleavage rate was noted and, finally, the embryos were prepared for confocal laser scanning microscopy and transmission electron microscopy. There was no difference between the groups regarding cleavage rate, the cytoskeleton, or the number of active nucleoli. However, the ACTH group had significantly (p < 0.05) fewer ova/embryos retrieved (51%) than the C group (81%), and there was a tendency towards faster transportation to the uterus in the ACTH group, possibly because of high progesterone concentrations during treatment. To conclude, administration of ACTH every 4 h from onset of oestrus to 48 h caused significant loss of oocytes or embryos, and possibly faster transportation through the oviduct.
Development of a Competitive Quantitative PCR Strategy for Evaluating the Expression Stability of 18s rRNA during In Vitro Maturation of Buffalo (Bubalus bubalis) Follicular Oocytes
Authors: Aswal APS , Datta TK , Raghav S , De S , Yadav P , Goswami SL 
Published: February 2007

ContentsThe present work describes the development of a quantitative competitive PCR strategy for quantifying the relative abundance of 18s rRNA transcripts in buffalo oocytes during in vitro maturation (IVM). As a method, the competitive PCR overcomes some of the shortcomings of conventional reverse transcriptase polymerase chain reaction (RT‐PCR) procedure making it a more authentic quantitative method. A composite primer based approach was used to generate the competitor cDNA to be used as external control. Validity of the method for its efficiency was demonstrated by quantitative analysis of the competition parameters. Using this method the relative abundance of buffalo oocyte 18s rRNA transcript over the period of IVM was found to vary within a narrow range of 0.93–1.06 folds which establishes the accuracy of the method and reflects the stability of its expression during IVM. This qualifies the use of this house keeping gene as a valid internal control in studies investigating the gene expression pattern in buffalo oocytes. The competitive PCR approach described in this study could be used for quantification of other transcripts from a limited number of oocytes where a conventional RT‐PCR method is either difficult to use or multiplexing it with highly abundant house keeping genes is apparently problematic.
Multinuclear–Multiflagellar Sperm Defect in a Bull – a New Sterilizing Sperm Defect
Authors: Kopp C , Sukura A , Tuunainen E , Gustavsson I , Parvinen M , Andersson M 
Published: February 2007

ContentsThe development and use of modern techniques, such as intracytoplasmic sperm injection (ICSI), gene knockout and sperm fluorescence in situ hybridization with chromosome‐ specific probes, have significantly increased our knowledge about sperm defects. We describe a new oligoasthenoteratozoospermic defect in a bull. Because of its morphological characteristics the defect was named the multinuclear–multiflagellar sperm defect. All spermatozoa in the ejaculate were abnormal. Many of the spermatozoa had multiple nuclei and multiple sperm tails. All spermatozoa lacked an acrosome, and only seldom did spermatozoa have a mitochondrial helix in the midpiece area. Meiosis and spermiogenesis were severely affected in this otherwise phenotypically normal bull. The sperm defects resembled the phenotype of a targeted gene knockout Hrb−/−(HIV‐1 Rev‐binding/interacting protein) mutant mouse strain, which is expressed as sterility in males, while females remain fertile. Since the father of this bull has been extensively used in at least three countries the defective gene has possibly become widespread in the red and white breeds (Ayrshire, Swedish Red and White, Norwegian Red) in the Nordic countries. However, it is not proved that the father of this bull is a carrier of this defect.
Age, FSH Dose and Follicular Aspiration Frequency Affect Oocyte Yield from Juvenile Donor Lambs
Authors: Valasi I , Leontides L , Papanikolaou Th , Amiridis GS 
Published: February 2007

ContentsExperiments were conducted to determine the effects of lamb age, frequency of follicular aspirations, and hormone stimulation by fixed or variable FSH dose, on the number of collected oocytes and their maturational competence. In trial 1, the characteristics of follicular population (number and diameter of follicles) were studied in 40 lambs which were slaughtered at the age of 30 days (S1), 42 days (S2), 60 days (S3) and 5–6 months (S4), each n = 10. In trial 2, 27 lambs were divided into four groups. group MF lambs (n = 6) had follicular aspiration (OPU) in four monthly intervals commencing from the age of 8–9 weeks (sessions MF1, MF2, MF3 and MF4). In groups SF2, SF3 and SF4 (each n = 6), OPU was conducted once during the 12–13, 16–17 and 20–21 week of age, respectively. Ovarian stimulation was conducted with fixed FSH dose (3.52 mg/animal). In trial 3, 10 lambs (group MV) were treated as those of group MF apart from the FSH dose, which was administered according to the body weight in a dose of 0.27 mg/kg. The number and the size of follicles, the number and the quality of collected oocytes and the maturational competence of the oocytes were compared between and within groups. In trial 1, the total number and the number of small follicles were greater in groups S1 and S2 compared with those of S3 and S4 (p < 0.01). Similarly, the follicular population was greater in group MF1 than in group SF3 (p < 0.01). In sessions MF2, MF3, MV2, MV3 and MV4, more oocytes were collected in comparison with those from the respective once‐aspirated age mates (groups SF2, SF3 and SF4). In total, more (p = 0.02) oocytes per donor were collected from group MV (15.2 ± 5.5) than from group MF (9.0 ± 3.2). An absolute maturational failure was observed in oocytes collected from groups SF2 and SF3. Maturational competence varied between 16.7% and 58.3% (p = 0.017) among sessions of group MF, but it was more uniform among sessions of group MV (range 12.5–42.9%, p > 0.05). Our results indicate that firstly, the number and the quality of harvested oocytes from juvenile lambs can be much improved if follicular stimulation regime is adjusted to the body weight. Secondly, in terms of follicular population and oocyte quality, 3 and 4‐month‐old lambs are naturally bad oocyte donors, but this characteristic can be reversed by a previous follicular ablation.
Measurement of Faecal Progesterone Metabolites and its Application for Early Screening of Open Cows Post‐insemination
Authors: Kornmatitsuk B , Thitaram C , Kornmatitsuk S 
Published: February 2007

ContentsThe present study investigated the changes of serum progesterone (P4) and its faecal metabolites in pregnant and non‐pregnant cows (Expt 1) and the feasibilty of using faecal P4 metabolites for early screening of open cows post‐insemination (Expt 2). In Expt 1, seven crossbred Holstein–Friesian (HF) cows were studied. Serum and faecal samples were collected once daily from the day of artificial insemination (AI) until 25 days after AI. In Expt 2, 27 crossbred HF inseminated cows were employed. Serum and faecal samples were obtained on the day of AI (day 0) and on days 19–22 post‐insemination. Enzyme immunoassay measurements of serum P4 and faecal P4 metabolites were established. The low detection limit of the assay was 0.01 ng/ml and the amount of P4, resulting in a 50% reduction in the initial binding value, was 1.07 ng/ml. The intra‐ and inter‐assay coefficients of variation were <8% and <14%, respectively. A positive correlation between the levels of serum P4 and faecal P4 metabolites was found in every single cow (r = 0.73−0.88, p < 0.001) and pooled data (r = 0.78, p < 0.001). The estimated value of faecal P4 metabolites at 100 ng/g of faeces was equal to the serum P4 levels of 1 ng/ml. The accuracies of pregnancy and non‐pregnancy diagnosis based on the analyses of faecal P4 metabolites between day 0 and days 19–22 post‐insemination, were 67% and 100%, respectively. In conclusion, the measurement of faecal P4 metabolites can be a potentially alternative method for early screening of open cows post‐insemination with the same accuracy and precision, as measured by serum P4 assay.
Heterospecific Nuclear‐transferred Embryos Derived from Equine Fibroblast Cells and Enucleated Bovine Oocytes
Authors: Zhou H , Liu C , Wang W 
Published: February 2007

ContentsThis study was conducted to reconstruct heterogeneous embryos using equine skin fibroblast cells as donor karyoplasts and the bovine oocytes as recipient cytoplast for investigating the reprogramming of equine somatic cell nuclear in bovine oocyte cytoplasm and the developmental potential of the reconstructed embryos. Adult horse skin fibroblast cells serum‐starved were used as donor somatic cells. Bovine oocytes matured in vitro were employed as recipient cytoplasts. The fusion of fibroblast cells into recipient cytoplasm was induced by electofusion. The fused eggs were activated by inomycin with 2 mm/ml 6‐dimethylaminopurine (6‐DMAP). The activated reconstructed embryos were co‐cultured with bovine cumulus cells in synthetic oviduct fluid supplemented with amino acid (SOFaa) and 10% fetal calf serum (FCS) for 168 h. The results showed that the first completed cleavage of xenonuclear transfer equine embryos occurred between 30 and 48 h following activation. 52% of the injected oocytes were successfully fused, 72% of the fused eggs underwent the first egg cleavage and 17% of the heterospecific nuclear‐transferred zygotes developed to 4‐ or 8‐cell embryo stages. This study demonstrated that the reconstructed embryos have undergone the first embryonic division and the reprogramming of equine fibroblast nuclei can be initiated in bovine‐enucleated oocytes.
Vitamin E Biochemistry and Function: A Case Study in Male Rabbit
Authors: Castellini C , Mourvaki E , Dal Bosco A , Galli F 
Published: February 2007

ContentsVitamin E supplementation has become a common procedure to promote growth and health and improve the qualitative characteristics of farm animals. It has been demonstrated to be an efficient strategy for improving their reproductive function. Germ cells are particularly vulnerable to oxidative damage and may thus require additional antioxidant protection. The aim of this review is to give a comprehensive overview of the current knowledge of the biochemistry and physiology of vitamin E; successively, the effect of this compound on the reproductive activity of rabbit buck is accurately described. In particular, this review examines studies on the effects of animal age, dose and duration of vitamin E supplementation, as well as the co‐supplementation with selenium, vitamin C and polyunsaturated fatty acids. Several investigations have shown beneficial effects in bucks supplemented with vitamin E levels higher than the standard dietary requirement (50 mg/kg) particularly when the semen is stored. However, the exact dietary intake of vitamin E should be decided according to specific tissue needs for the individual vitamin E forms and the specific saturation markers.
Ketamine disposition in children presenting for procedural sedation and analgesia in a children's emergency department
Authors: HERD DAVID , ANDERSON BRIAN J. 
Published: February 2007

SummaryBackground:  The aim of this study was to describe ketamine pharmacokinetics in children to simulate time–concentration profiles to predict duration of concentrations associated with anesthesia, arousal and analgesia.Methods:  Children presenting for painful procedures in the Emergency Dept were given ketamine 1–1.5 mg·kg−1 i.v. Blood was assayed for ketamine on 3–6 occasions (median 3) over the subsequent 14–152 min (median 28.5). A population pharmacokinetic analysis was undertaken by using nonlinear mixed effects models (NONMEM). Simulation was used to predict time–concentration profiles in this cohortResults:  There were 188 observations from 54 children (age 8.3 sd 3.5 years, weight 32.5 sd 15.6 kg). A two‐compartment (central, peripheral) linear disposition model fitted data better than a one‐compartment model. Population parameter estimates and their between subject variability (BSV), standardized to a 70‐kg person using allometric models, were central volume (V1) 38.7 (BSV 64%) l.70 kg−1, peripheral volume of distribution (V2) 102 (51.7%) l.70 kg−1, clearance (CL) 90 (38.1%) l·h−1 70 kg−1 and intercompartment clearance (Q) 215 (19%) l·h−1 70 kg−1. At 10 min half of the children given 1 mg·kg−1 will have a serum concentration below 0.75 mg·l−1. This is a concentration associated with ‘awakening’ in adults. However, almost all the children will still have a serum concentration above 0.1 mg·l−1, a level associated with analgesia in adults.Conclusions:  Ketamine 1 mg·kg−1 i.v. provides satisfactory serum concentrations for children undergoing sedation for painful procedures of <5‐min duration and produces concentrations associated with analgesic effect for more than 10 min. Clearance increases with decreasing age in children. The relationship between serum concentration and effect is poorly defined in children.
Invasiveness in plant communities with feedbacks
Authors: Eppstein Margaret J. , Molofsky Jane 
Published: February 2007

AbstractThe detrimental effects of invasive plant species on ecosystems are well documented. While much research has focused on discovering ecological influences associated with invasiveness, it remains unclear how these influences interact, causing some introduced exotic species to become invasive threats. Here we develop a framework that incorporates the influences of propagule pressure, frequency independent growth rates, feedback relationships, resource competition and spatial scale of interactions. Our results show that these ecological influences interact in complex ways, resulting in expected outcomes ranging from inability to establish, to naturalization, to conditional invasion dependent on quantity and spatial distribution of propagules, to unconditional takeover. We propose a way to predict the likelihood of these four possible outcomes, for a species recently introduced into a given target community. Such information could enable conservation biologists to craft strategies and target remediation efforts more efficiently and effectively in order to help maintain biodiversity in ecological communities.