bluuebunny/crossref_metadata_2025_split huggingface dataset:
Androgens and Immune Function in Male Alternative Reproductive Morphotypes of the Peacock Blenny Salaria pavo
Authors: Ros Albert F. H. , Oliveira Rui F. 
Published: May 2009

AbstractSpecies with alternative reproductive tactics offer the opportunity to analyse how behavioural and morphological traits are tuned to produce successfully competing phenotypes within one sex. In the teleost fish Salaria pavo, alternative reproductive tactics are sequential. The older ornamented males compete for access to females by guarding a cavity to which they attract females to spawn. Ornamented males that are found without a nest are called ‘floaters’. Younger mature males which are too small to compete with nest‐holders attempt to ‘sneak’ as female mimics into successful nests and release their sperm to fertilize freshly spawned eggs. The alternative tactics in S. pavo are associated with different levels of the androgens testosterone and 11‐ketotestosterone, which have been found to suppress immune function in several teleost fish. A field study was carried out to analyse the relationship between these reproductive tactics, androgens and blood levels of lymphocytes as a monitoring method of immune function. We expected highest investment in the immune system in sneakers because these have the lowest androgen levels and functionally because investing in self‐maintenance increases their future prospect to switch tactic and to reproduce as a nest‐holder. Indeed, the relative count of lymphocytes correlated negatively with body size and thus was highest in sneakers and lowest in nest‐holders. In concordance, 11‐ketotestosterone and testosterone levels were found to be higher in floaters and nest‐holders than in sneakers. However, no correlation was found between individual levels of testosterone or 11‐ketotestosterone and lymphocytes. Thus, a trade‐off between reproductive traits associated with high androgen levels and immunocompetence might exist at the level of alternative tactics but this might not be explained by acute immunosuppressive effects of circulating androgens.
The Development of Geographic Song Preferences in Female Song Sparrows Melospiza melodia
Authors: Hernandez Alexandra M. , Pfaff Jeremy A. , MacDougall‐Shackleton Elizabeth A. , MacDougall‐Shackleton Scott A. 
Published: May 2009

AbstractPrevious work suggests that early learning plays a role in auditory preferences of female songbirds. We explored whether early experience shapes preferences for local geographic song in female song sparrows (Melospiza melodia), a species that prefers local geographic song in adulthood. We hand‐reared females from two locations 450 km apart and controlled song exposure early in life. To examine the effects of experience and inherited factors on geographic song preferences, we used a counterbalanced design. Females from each location were tutored with either natal song (recorded from their location of capture) or non‐natal song (recorded from the other location) and their preferences for tutor vs. non‐tutor song assessed in adulthood. We also examined song preferences in isolate females reared with no song experience. We found that tutored females preferred their tutor song over non‐tutor song, regardless of their capture location. Furthermore, birds not exposed to song (isolates) had no geographic song preferences. Thus, song exposure early in life clearly plays an important role in adult female preferences for local song in this species.
Do Primary Males Physiologically Suppress Subordinate Males? An Experiment in a Cooperatively Breeding Passerine
Authors: Brouwer Lyanne , Groothuis Ton G. G. , Vedder Oscar , Eikenaar Cas , Richardson David S. , Komdeur Jan 
Published: May 2009

AbstractKnowing why certain individuals refrain from reproduction is fundamental to our understanding of the evolution of cooperative breeding. Although many studies have focused on the role of life history and ecological factors, the proximate mechanisms underlying this behaviour have received considerably less attention. We determined the natural variation in plasma testosterone (T) level and cloacal protuberance (CP) size – an indication of sperm storage – in successfully reproducing primary male and in reproductively inactive subordinate male Seychelles warblers (Acrocephalus sechellensis). Primary males had significantly higher T levels during female’s fertile period and significantly larger CPs throughout the breeding season than subordinate males. To test if the lower T levels of subordinates were caused by their social status per se, we experimentally promoted subordinates to primary males, by permanent removal of primary males from their territories. The experimentally promoted males increased T production and CP sizes significantly, suggesting former suppression by primary males. However, T levels of the promoted males only marginally increased. As this could not be explained by their younger age, we conclude that recovery from social suppression may take a substantial time period.
Stereotypic behaviour in farm mink (Neovison vison) can be reduced by selection
Authors: Hansen B.K. , Jeppesen L.L. , Berg P. 
Published: May 2009

SummaryIn this article we present the first estimation of genetic variation of stereotypic behaviour (SB). Stereotypic behaviour is defined as an unvarying behaviour without any specific goal or function repeated at least five times. All types of SB were included in the analyses. Altogether 1484 adult mink females of the brown colour type were assessed for behaviour traits: SB, active or inactive behaviour, staying in nest box. Genetic correlations were based on estimates of additive genetic (co)variances obtained from a trivariate linear animal model fitted to behaviour traits, body weight and litter size. The SB has an intermediate genetic variation (h2∼0.3) and divergent selection for SB confirmed that the frequency of SB can be altered by selection. The results confirmed the hypotheses of negative genetic correlation between SB and body weight and negative genetic correlation between body weight and litter size. The hypotheses of positive correlation between SB and active behaviour and SB and litter size were not confirmed. Consequences of selection for reduced SB can be changes in other behaviour traits, body weight and litter size, depending on the genetic correlation between the traits.
Theoretical efficiency of multiple‐trait quantitative trait loci‐assisted selection
Authors: Togashi K. , Lin C. Y. 
Published: May 2009

SummaryThe effectiveness of five selection methods for genetic improvement of net merit comprising trait 1 of low heritability (h2 = 0.1) and trait 2 of high heritability (h2 = 0.4) was examined: (i) two‐trait quantitative trait loci (QTL)‐assisted selection; (ii) partial QTL‐assisted selection based on trait 1; (iii) partial QTL‐assisted selection based on trait 2; (iv) QTL‐only selection; and (v) conventional selection index without QTL information. These selection methods were compared under 72 scenarios with different combinations of the relative economic weights, the genetic correlations between traits, the ratio of QTL variance to total genetic variance of the trait, and the ratio of genetic variances between traits. The results suggest that the detection of QTL for multiple‐trait QTL‐assisted selection is more important when the index traits are negatively correlated than when they are positively correlated. In contrast to literature reports that single‐trait marker‐assisted selection (MAS) is the most efficient for low heritability traits, this study found that the identified QTL of the low heritability trait contributed negligibly to total response in net merit. This is because multiple‐trait QTL‐assisted selection is designed to maximize total net merit rather than the genetic response of the individual index trait as in the case of single‐trait MAS. Therefore, it is not economical to identify the QTL of the low heritability traits for the improvement of total net merit. The efficient, cost‐effective selection strategy is to identify the QTL of the moderate or high heritability traits of the QTL‐assisted selection index to facilitate total economic returns. Detection of the QTL of the low h2 traits for the QTL‐assisted index selection is justified when the low h2 traits have high negative genetic correlation with the other index traits and/or when both economic weights and genetic variances of the low h2 traits are larger as compared to the other index traits of higher h2. This study deals with theoretical efficiency of QTL‐assisted selection, but the same principle applies to SNP‐based genomic selection when the proportion of the genetic variance ‘explained by the identified QTLs’ in this study is replaced by ‘explained by SNPs’.
Nuclear Configuration, Spindle Morphology and Cytoskeletal Organization of In Vivo Maturing Horse Oocytes
Authors: Siddiqui MAR , Gastal EL , Ju JC , Gastal MO , Beg MA , Ginther OJ 
Published: May 2009

ContentsHorse oocytes (n = 37) were recovered in vivo from pre‐ovulatory follicles 30 h after an ovulation‐inducing hCG injection and were examined by fluorescent staining and confocal microscopy. Percentages of metaphase‐I (MI), metaphase‐II (MII) and atypical oocytes were 11%, 78% and 11% respectively. Microtubules were concentrated in the meiotic spindle in both MI and MII oocytes. Chromosomes in the metaphase plate were anchored at the equatorial region of the spindle. Spindle orientation was perpendicular to the oolema in all MI oocytes, whereas in MII oocytes, 66% were parallel and 34% were perpendicular. In MII oocytes, the nuclear material in the polar body had no specific organization and was intertwined with microtubules. Discrete foci of microfilaments at the sub‐cortical region of the ooplasm formed an F‐actin band, as seen in the inner confocal sections. The percentage area of oocyte image with discrete foci and/or the thickness of F‐actin band was used to indicate microfilament content. Microfilament content was greater (p < 0.006) in MII oocytes than in MI oocytes and greater (p < 0.03) in MII oocytes with a perpendicular spindle than with a parallel spindle. The perpendicular spindle orientation in MII oocytes may have represented a later stage of maturation. Atypical oocytes were based on microtubules that were detached from the kinetochores and spread in the ooplasm or by microtubules that accumulated as an amorphous mass near the condensed chromatin. This is the first description of the nuclear configuration, spindle morphology and cytoskeletal organization of in vivo maturing horse oocytes.
Development of One vs Multiple Ovulatory Follicles and Associated Systemic Hormone Concentrations in Mares
Authors: Ginther OJ , Jacob JC , Gastal MO , Gastal EL , Beg MA 
Published: May 2009

ContentsAblation of follicles ≥  6 mm in diameter and treatment with PGF2α 10 days after ovulation were used to induce the development of ovulatory waves. Comparisons were made between induced waves with one (33 waves, 72%) and multiple (13 waves, 28%) ovulatory follicles. Diameter deviation was defined as the separation of follicles into dominant and subordinate categories. Multiple ovulatory follicles were preceded by more (p < 0.001) follicles ≥ 20 mm at the beginning of deviation, higher LH preceding deviation (approached significance, p < 0.08), lower (p < 0.05) concentrations of FSH on the day of deviation and thereafter, and higher (p < 0.0003) oestradiol by 2 days after deviation. During the peri‐ovulatory period, systemic hormone concentrations for waves with multiple ovulations involved higher oestradiol before ovulation (approached significance, p < 0.07), lower FSH (p < 0.04) before and after ovulation, and both higher progesterone (p < 0.05) and lower LH (p < 0.05) beginning the day after ovulation. Results indicated that by the beginning of deviation there were more follicles ≥  20 mm and subsequently greater oestradiol production in waves that led to the development of multiple ovulatory follicles, and during the peri‐ovulatory period differences between one and multiple ovulations were consistent with the negative effects of the ovarian hormones on the gonadotropins.
Basic fibroblast growth factor increases the precursor pool of photoreceptors, but inhibits their differentiation and apoptosis in chicken retinal reaggregates
Authors: Frohns Florian , Mager Magnus , Layer Paul G. 
Published: May 2009

AbstractThe role(s) of basic fibroblast growth factor (bFGF, FGF‐2) in the differentiation and survival of photoreceptor (PR) cells was investigated in three‐dimensional reaggregated histotypic spheres, derived from dispersed cells of the embryonic day 6 chicken embryo retina. Novel data processing methods are introduced to reliably quantify sphere sizes and spatial distributions of immunochemical signals in spheroids. Supplementation with 25 ng/mL FGF‐2 increased cell proliferation, detected by bromodeoxyuridine uptake, and growth of spheroids. Immunochemical studies showed that FGF‐2 decreased the number of visinin‐positive and XAP‐1‐positive cells, including the total PR pool from early precursor until mature states, whereas the number of Pax6‐positive amacrine cells was strongly increased. Notably, the relative number of PR precursors as detected by an Islet2 antibody was increased. The further differentiation of both red/green cones and then rods, as detected by CERN‐906 and CERN‐901 antibody binding, was much delayed. In contrast, blocking system‐inherent FGF‐2 by suramin showed opposite effects. Addition of both FGF‐2 plus suramin resulted in nearly normal levels of PR differentiation. Terminal deoxynucleotidyl transferase dUTP nick end labelling histochemistry showed that PR apoptosis, which generally progresses with the age of spheres, was strongly increased by suramin treatment. These results suggest that in a three‐dimensional retinal tissue context, FGF‐2 restricts the pool of PRs in favour of cells of the inner retina, increases and maintains their precursor pool, delays their differentiation, and also protects them from apoptosis.
Streamlining ‘search and destroy’: cost‐effective surveillance for invasive species management
Authors: Hauser Cindy E. , McCarthy Michael A. 
Published: May 2009

AbstractInvasive species surveillance has typically been targeted to where the species is most likely to occur. However, spatially varying environmental characteristics and land uses may affect more than just the probability of occurrence. Biodiversity or economic value, and the ease of detection and control are also likely to vary. We incorporate these factors into a detection and treatment model of a low‐density invader to determine the surveillance strategy that minimizes expected management costs. Sites with a high probability of invader occurrence and great benefits associated with detection warrant intensive surveillance; however, the optimum investment is a nonlinear function of these factors. Environments where the invader is relatively easy to detect are prioritized for surveillance, although only a moderate investment is necessary to ensure a high probability of detection. Intensive surveillance effort may be allocated to other sites if the probability of occurrence, budget and/or expected benefits is sufficiently high.
The optimum approach for pre‐transplant bilateral nephrectomy in small kidneys: dorsal lumbotomy vs laparoscopy
Authors: Srivastava Aneesh , Muruganandham Kaliyaperumal , Gupta Parag , Dubey Deepak , Kapoor Rakesh , Kumar Anant , Gupta Amit , Sharma Raj Kumar 
Published: May 2009

OBJECTIVETo evaluate the outcomes of bilateral pretransplant nephrectomy (BPN) for small kidneys, using a bilateral dorsal lumbotomy (BDL) or transperitoneal laparoscopy (TL) approach.PATIENTS AND METHODSFifty‐eight patients with end‐stage renal disease and small kidneys underwent BPN for various indications, most commonly uncontrolled hypertension. There were 38 patients in the BDL group (group 1) and 20 in the TL group (group 2). The variables before and during surgery, and the outcomes afterward, were compared between the groups.RESULTSThe mean age of the patients and male/female ratio were comparable in both groups. The mean size of the kidneys removed were 7.4 and 8.2 cm, respectively, in groups 1 and 2. The mean (range) operative duration was longer in group 2, at 210  (160–240) min, than in group 1, at 112  (90–150) min (P < 0.001). The postoperative analgesic requirement for pain, blood transfusion rate, wound and pulmonary complications were similar between the groups. Bowel function recovered earlier in group 1 than group 2 (19 vs 37 h, P < 0.001). The total cost for the nephrectomy in group 2 was 3.5 times that of group 1. The mean interval between nephrectomy and transplantation was similar in both groups.CONCLUSIONBDL appears to be better than TL for BPN in small kidneys because the surgery is quicker, and there is earlier bowel recovery and lower costs.
Effect of diversification on capital structure
Authors: La Rocca Maurizio , La Rocca Tiziana , Gerace Dionigi , Smark Ciorstan 
Published: May 2009

AbstractPrevious empirical financial studies have paid little attention to the role of diversification strategy on financial choices. This study analyses the financing strategies of multibusiness firms, suggesting the relevance of sorting the diversification phenomena into its related and unrelated components. The implications of our findings are important because they explain earlier contradictory results on capital‐structure determinants and offer an explanation of how the degree of product specialization/diversification and the direction of diversification (related or unrelated) translate into different corporate financial behaviours.
Market's perception of deferred tax accruals
Authors: Chang Cheryl , Herbohn Kathleen , Tutticci Irene 
Published: May 2009

AbstractThis study investigates the value relevance and incremental information content of deferred tax accruals reported under the ‘income statement method’ (AASB 1020 Accounting for Income Taxes) over the period 2001–2004. Our findings suggest that deferred tax accruals are viewed as assets and liabilities. We document a positive relation between recognized deferred tax assets and firm value using the levels model, while the results from the returns model suggest that deferred tax liabilities reflect future tax payments. The balance of unrecognized deferred tax assets provides a negative signal to the market about future profitability, particularly for companies from the materials and energy sectors and loss‐makers.
Paediatric obesity, physical activity and the musculoskeletal system
Authors: Shultz S. P. , Anner J. , Hills A. P. 
Published: May 2009

SummaryThe current epidemic of paediatric obesity is consistent with a myriad of health‐related comorbid conditions. Despite the higher prevalence of orthopaedic conditions in overweight children, a paucity of published research has considered the influence of these conditions on the ability to undertake physical activity. As physical activity participation is directly related to improvements in physical fitness, skeletal health and metabolic conditions, higher levels of physical activity are encouraged, and exercise is commonly prescribed in the treatment and management of childhood obesity. However, research has not correlated orthopaedic conditions, including the increased joint pain and discomfort that is commonly reported by overweight children, with decreases in physical activity. Research has confirmed that overweight children typically display a slower, more tentative walking pattern with increased forces to the hip, knee and ankle during ‘normal’ gait. This research, combined with anthropometric data indicating a higher prevalence of musculoskeletal malalignment in overweight children, suggests that such individuals are poorly equipped to undertake certain forms of physical activity. Concomitant increases in obesity and decreases in physical activity level strongly support the need to better understand the musculoskeletal factors associated with the performance of motor tasks by overweight and obese children.
AN EXACT TEST FOR HAZARD SIMILARITY
Authors: Hamza Kais 
Published: May 2009

SummaryAn exact test is developed for hazard similarity and in particular for exponentiality. This test is distinct from more common goodness‐of‐fit tests such as the Kolmogorov–Smirnov goodness‐of‐fit test, as it does not require full specification of the null distribution. This test is obtained through a characterization of hazard‐similar distributions and a generalization of Fisher's test for association.
The Process of Fixing the British National Minimum Wage, 1997–2007
Authors: Brown William 
Published: May 2009

AbstractThe British National Minimum Wage was introduced in 1999 under the guidance of a Low Pay Commission constructed on a basis of ‘social partnership’. The article analyses its conduct over its first 10 years from diary data. Key challenges were for it to be independent of government, to have its advice accepted by government and to maintain internal unanimity. The changing internal dynamics of the Commission, and its major negotiations over the level of the minimum wage, are described and analysed. Conclusions are drawn for the social partnership process.
Publication Selection Bias in Minimum‐Wage Research? A Meta‐Regression Analysis
Authors: Doucouliagos Hristos , Stanley T. D. 
Published: May 2009

AbstractCard and Krueger's meta‐analysis of the employment effects of minimum wages challenged existing theory. Unfortunately, their meta‐analysis confused publication selection with the absence of a genuine empirical effect. We apply recently developed meta‐analysis methods to 64 US minimum‐wage studies and corroborate that Card and Krueger's findings were nevertheless correct. The minimum‐wage effects literature is contaminated by publication selection bias, which we estimate to be slightly larger than the average reported minimum‐wage effect. Once this publication selection is corrected, little or no evidence of a negative association between minimum wages and employment remains.
Minimum Wage Impacts on Older Workers: Longitudinal Estimates from Canada
Authors: Fang Tony , Gunderson Morley 
Published: May 2009

AbstractWe use the longitudinal nature of the master file of the Survey of Labour and Income Dynamics in Canada for the period 1993–99 to estimate the employment impacts for older workers of the large number (24) of minimum wage increases that have occurred across the different provincial jurisdictions over that period. Perhaps somewhat surprisingly, the minimum wage increases have positive impacts on the employment of older workers compared with the negative impacts that are commonly estimated for youths in Canada. The results are robust across various comparison groups and measures of the minimum wage increases. Reasons for this unusual finding are discussed.
The Productivity‐Enhancing Impacts of the Minimum Wage: Lessons from Denmark and New Zealand
Authors: McLaughlin Colm 
Published: May 2009

AbstractThis article adds an international comparative perspective to the reflection on 100 years of minimum wage legislation in Britain by exploring the impact of minimum wage regulations and institutions in Denmark and New Zealand. In particular, it looks at the question of whether minimum wages can raise productivity through the ‘shock effect’. It argues that while they will play a role, a supportive institutional framework is more important in providing coordinated solutions to issues of market failure, such as inadequate levels of training. The article suggests that sectoral bargaining institutions in low‐paid sectors may have the potential to facilitate such coordination and enable the high‐productivity model to emerge.