bluuebunny/crossref_metadata_2025 huggingface dataset:
Affirmative Action in a Changing Legal and Economic Environment
Authors: BADGETT M. V. LEE
Published: May 2008

This study examines the effects of changing legal and economic pressure on a large manufacturing firm in the 1980s and shows that the firm was able to pursue two potentially contradictory goals: equal employment opportunity compliance and product market competitiveness. The firm's institutionalized affirmative action commitment and diverse local labor market shaped innovations in production and employment practices in a way that encouraged meeting both goals rather than trading off one for the other.
Youth Apprenticeship in Britain: Lessons for the United States
Authors: CAPPELLI PETER
Published: May 2008

Britain's effort to introduce youth apprenticeships over the past decade offers important general lessons about the role of employers in school‐to‐work initiatives. In particular, the incentives facing employers work against efforts to provide skills training. Alternative arrangements for such programs are suggested that create incentives for employers to improve the skills of youth apprentices.
Gender and Race Differences in Company Training
Authors: VEUM JONATHAN R.
Published: May 2008

Using recent data from the National Longitudinal Survey of Youth, it is found that among young workers from 1986 to 1991, there were no gender or race differentials in the likelihood of receiving training, in participation in multiple training events, or in hours of training received. White women, however, were more likely to receive more training per hour worked than white men. This gender differential appears to occur because white women are more likely to work fewer hours and to be employed in entry‐level positions that are associated with greater training intensity.
On‐the‐Job Training, Immigration Reform, and the True Wages of Native Male Workers
Authors: PAGÁN JOSÉ A. , DÁVILA ALBERTO
Published: May 2008

This study measures the Immigration Reform and Control Act's (IRCA) impact on the “true” earnings of native workers. True earnings include observed wages and compensation received in the form of on‐the‐job training (OJT). Using 1983–1992 NLSY data, we present evidence suggesting IRCA reduced the true wages of male natives most likely to be mistaken as unauthorized. Our findings suggest that Mexican Americans suffered the largest decline in post‐IRCA OJT. It appears then that antidiscrimination policies following recent immigration reform have not fully protected some U.S. natives against unintended IRCA‐related employment discrimination.
Gender Differences in the Returns to and the Acquisition of On‐the‐Job Training
Authors: OLSEN REED NEIL , SEXTON EDWIN A.
Published: May 2008

This article finds that gender differences in on‐the‐job training significantly affect the male/female wage gap. First, we find that previously trained workers exhibit larger cumulative wage gains during their current training. Thus, a substantial portion of the gender wage gap results from the fact that women have little prior training relative to men. Second, a significant amount of the observed male/female wage differential is explained by less female acquisition of current training. Gender differences in workplace promotion and training practices help explain why women accumulate less training than men. Both of these sources of gender differences have lessened from 1976 to 1985, which has led to a narrowing of the male/female wage gap.
Earnings Mobility and Long‐Run Inequality: An Analysis Using Matched CPS Data
Authors: GITTLEMAN MAURY , JOYCE MARY
Published: May 2008

In this article we use matched cross sections from the Current Population Survey (CPS) to examine patterns of short‐term earnings mobility for the period 1967‐91, which we then employ to assess the impact of rising annual individual earnings inequality on inequality over a longer span, First, we find that less‐educated individuals and blacks have more instability in their earnings than those who are more highly educated and non‐black. Second, short‐term mobility levels have not undergone major changes over the time span we examine. Third, our results suggest that long‐run inequality (calculated over five years) rose in the latter half of the 1980s. Fourth, important differences exist across demographic groups in long‐run inequality trends, with long‐term inequality increasing most in the 1980s for less‐educated males.
The Postmilitary Earnings of Female Veterans
Authors: MEHAY STEPHEN L. , HIRSCH BARRY T.
Published: May 2008

The role of women in the military has grown rapidly. Using standard datasets and a special survey of reservists, female veterans are found to have better earnings endowments than nonveterans. Although female veterans have higher unadjusted earnings than nonveterans, a wage disadvantage is found for white but not nonwhite veterans following control for measured and unmeasured skills. Low returns to military service may result from historically limited military opportunities for women and difficulty in transferring skills to civilian jobs.
Factors Influencing Organizational Performance in Gainsharing Programs
Authors: KIM DONG‐ONE
Published: May 2008

Using survey data from managers at 269 establishments in the United States and Canada, this article examines factors influencing outcomes of gainsharing. The ordered probit analyses generally indicated that these outcomes have significant associations with employee involvement, bonus payouts, employee bonus share, bonus group size, consultant involvement, the administration of employee votes, labor intensity, market situation, establishment's financial condition, the average seniority level of employees, union status, and union support.
MAPs: Labor‐Based Peer Assistance in the Workplace
Authors: BACHARACH SAMUEL B. , BAMBERGER PETER A. , SONNENSTUHL WILLIAM J.
Published: May 2008

An offshoot of management‐based Employee Assistance Programs, Member Assistance Programs (MAPs) are peer‐based programs designed to help union members suffering from substance abuse and other personal problems. Although a relatively recent phenomenon, MAPs are rooted in traditional union principles of voluntarism and mutual aid. This article examines the emergence and growing popularity of MAPs, differences in MAP structure and orientation across unions, and the potential significance of MAPs to unions and industrial relations.
Gender, Race, and Promotions within a Private‐Sector Firm
Authors: PAULIN ELIZABETH A. , MELLOR JENNIFER M.
Published: May 2008

This article empirically tests the proposition that the gender‐race composition of an employee's occupation significantly affects the likelihood of promotion. Using data obtained from the personnel files of a financial services firm, we find that a high concentration of white females in an occupation adversely affects the probability of promotion, but only for white females and minorities in that occupation. A similar, attenuated pattern exists in occupations with either high concentrations of minority females or high concentrations of minority males. Additional empirical evidence suggests that the system of rules governing the promotion of white males differs significantly from that of the other three gender‐race groups.
Diffusion and Performance of Modular Production in the U.S. Apparel Industry
Authors: DUNLOP JOHN T. , WEIL DAVID
Published: May 2008

This article examines the determinants of the diffusion of team production systems (modular assembly) and the impact of these systems on firm performance relative to traditional assembly systems in the apparel industry. The article draws on an extensive survey providing detailed information on a wide range of manufacturing practices and retail relationships in the U.S. apparel industry. We find that recent diffusion of modular practices is driven primarily by the product market. We also show that modular systems affect business‐unit performance (particularly operating profits) where they are combined with complementary investments in information systems linking apparel suppliers with retail customers.
The Performance Effects of Modular Production in the Apparel Industry
Authors: BERG PETER , APPELBAUM EILEEN , BAILEY THOMAS , KALLEBERG ARNE L.
Published: May 2008

This article identifies and explains differences in performance between two widely used alternative work methods‐module and bundle production—in the basics sector of the apparel industry. This research is based on interviews with managers and surveys of worker attitudes and perceptions. We find that a team production system in the apparel industry, called modules, performs better than the traditional bundle system on such measures as quality, costs, and responsiveness to retailers. Modules also perform better than bundles in reducing work‐in‐process inventory and throughput time. We argue that performance improvements are realized through coordination among the team members as a result of their ability to self‐regulate work, eliminate bottlenecks, resolve conflicts, help one another solve problems, and make improvements in the production process.
Participative Bureaucracy and Productivity in the Machined Products Sector
Authors: KELLEY MARYELLEN R.
Published: May 2008

In a participative bureaucracy, group‐based employee participation mechanisms provide opportunities to reexamine old routines and to take advantage of informal shortcuts that employees have worked out on their own. Instead of proving to be dinosaurs, older and larger bureaucratically structured organizations are demonstrating a capability for adaptation and change and achieving new productivity advantages through such participative structures. For small firms, a participative bureaucracy is complementary to the productive use of information technology in the machining process.
Methodological Issues in Cross‐Sectional and Panel Estimates of the Human Resource‐Firm Performance Link
Authors: HUSELID MARK A. , BECKER BRIAN E.
Published: May 2008

Because companies differ in factors such as management ability that may lead to both high performance work systems and enhanced firm performance, conventional estimates of the effects of human resource (HR) management practices on firm performance may be biased upward. Alternatively, if HR management practices are measured with error, estimates of their effects on firm performance may be biased downward. We find that although longitudinal estimates that avoid the first source of bias are substantially smaller than cross‐sectional estimates, the former are strongly influenced by errors in measuring HR management practices. Based on independent estimates of the measurement error, we calculate a range of estimates that correct for both biases. We estimate that a one standard deviation increase in our measure of high performance work systems raises the market value of the corporation by approximately $15,000 per employee.
Effects of Employment Outcomes on Changes to Policy Covering Police
Authors: SCHWOCHAU SUSAN
Published: May 2008

I examine influences on the probability that a state changed its labor relations policies covering municipal police to assess whether policy can be treated as an exogenous factor in analyses of employment outcomes. Multinomial logit estimates suggest a balancing of interests over time, with greater relative pay associated with decreases in the probability of union‐favorable policy changes and with increases in the probability of management‐favorable policy changes.
Unions and Police Productivity: An Econometric Investigation
Authors: BYRNE DENNIS , DEZHBAKHSH HASHEM , KING RANDALL
Published: May 2008

We examine the effect of unionization on police productivity in large U.S. metropolitan areas. We define police output in the context of a production function model that draws also on the crime literature. We estimate the resulting model using a data set that includes published and unpublished government statistics as well as our own survey of police departments. Results suggest that the effect of unions on police productivity varies according to categories of police performance. In particular, if performance is stratified according to the severity of crimes, unions seem to have an insignificant effect on police productivity with respect to serious crimes. For minor crimes, unionization alters the parameters of police production function, leading to diminished productivity.
Job Security Provisions and Employment: Revised Estimates
Authors: ADDISON JOHN T. , GROSSO JEAN‐LUC
Published: May 2008

This article provides estimates of the effect of statutory severance pay and notice on four labor market outcome indicators, closely following Lazear (1990) but correcting for errors in his dependent variables and covariates. Although we corroborate the directional influence of severance pay for three of the indicators, there is little to suggest that its contribution to rising unemployment is material. Also contrary to Lazear, longer notice appears to be associated with broadly favorable outcomes.
Anticonvulsants in Migraine Prophylaxis: A Cochrane Review
Authors: Mulleners WM , Chronicle EP
Published: May 2008

Several trials have asserted that some anticonvulsant drugs seem to be useful for the prophylaxis of migraine, but systematic reviews are sparse. We independently searched PubMed, EMBASE and the Cochrane Central Register of Controlled Trials until 2005, as well as Headache and Cephalalgia through April 2006, for prospective, controlled trials of anticonvulsant drugs. Data were calculated and pooled across studies and expressed as standardized mean differences, odds ratios and numbers-needed-to-treat. Anticonvulsants, considered as a class, reduce migraine frequency by about 1.3 attacks per 28 days compared with placebo, and more than double the number of patients for whom migraine frequency is reduced by ≥50% relative to placebo. Sodium valproate/divalproex sodium and topiramate were better than placebo, whereas acetazolamide, clonazepam, lamotrigine and vigabatrin were not; gabapentin, in particular, needs further evaluation. Trials designed with sufficient power to compare different drugs are also necessary.
Cortico-NRM Influences on Trigeminal Neuronal Sensation
Authors: Lambert GA , Hoskin KL , Zagami AS
Published: May 2008

We tested the idea that migraine triggers cause cortical activation, which disinhibits craniovascular sensation through the nucleus raphe magnus (NRM) and thus produces the headache of migraine. Stimulation of the dura mater and facial skin activated neurons in the NRM and the trigeminal nucleus. Stimulation of the NRM caused suppression of responses of trigeminal neurons to electrical and mechanical stimulation of the dura mater, but not of the skin. This suppression was antagonized by the iontophoretic application of the 5-HT1B/1D receptor antagonist GR127935 to trigeminal neurons. Migraine trigger factors were simulated by cortical spreading depression (CSD) and light flash. Activity of neurons in the NRM was inhibited by these stimuli. Multiple waves of CSD antagonized the inhibitory effect of NRM stimulation on responses of trigeminal neurons to dural mechanical stimulation but not to skin mechanical stimulation. The cortico-NRM-trigeminal neuraxis might provide a target for a more universally effective migraine prophylactic treatment.
Body dysmorphic disorder and dermatologists
Authors: Szepietowski JC , Salomon J , Pacan P , Hrehorów E , Zalewska A
Published: May 2008

The aim  of this study was to determine the frequency of body dysmorphic disorder (BDD) identified by Polish dermatologists and to evaluate the treatment modalities applied by them.

Methods  A specially designed questionnaire was distributed to 172 dermatologists. A total of 118 doctors responded (68.6%). The dermatologists were asked regarding demographic data, frequency of BDD in their everyday practice and methods of treatment they used in managing BDD patients.

Results  During the whole working period, over the half of dermatologists (64%) had observed at least one BDD patient in their practice. One fifth (20%) of the respondents observed 1 or 2 BDD cases during the past 5 years, 14% observed 3 to 5 such patients, 7% observed 5 to 10 BDD cases, and 5% of the doctors reported seeing more than 10 BDD patients within this period. Almost 18% of dermatologists were currently treating a BDD patient. Our data show that 40.7% of the respondents always ask and 28.8% often ask for a psychiatric opinion. More experienced dermatologists statistically more frequently (P < 0.05) obtained a psychiatric opinion about their patients. Only a small group of dermatologists (15.3%) use their own pharmacological treatment. If they do so, they first use anxiety‐relieving drugs and placebo.

Conclusion  BDD is a quite common disorder; however, not all dermatologists are sufficiently prepared to treat it. There is an urgent need for training of dermatologists on the effective approach to psychodermatoses.
The Diplomacy of Opting Out: A Bourdieudian Approach to National Integration Strategies*
Authors: ADLER‐NISSEN REBECCA
Published: May 2008

How are controversial national opt‐outs managed and perceived in the EU? This article argues that the United Kingdom and Denmark compensate diplomatically for the exclusionary effects of their exemptions. A Bourdieudian approach to national diplomacy in the EU is developed to explore how British and Danish officials handle their opt‐outs. By drawing on extensive interview data, it is demonstrated that the two opt‐out champions employ various sophisticated strategies to overcome the dilemma between autonomy and influence. Some diplomatic strategies reduce marginalization while others enhance it. National opt‐outs are ambiguous attempts at avoiding further European integration.
EVALUATION OF ARCHAEOLOGICAL LAYERS AIDED BY SPECTROMETRY AND ROBOTICS*
Authors: LEMAIRE A. , LUCE J.‐M. , CHILOT P. , BOUCHER Y. , TONDU B. , IPPOLITO S.
Published: May 2008

All archaeologists have faced the problem of interpreting stratigraphy. While this task can sometimes be very clear and unambiguous, this is far from always being the case. Because human beings are limited in their appreciation of soil by subjectivity and by the ability of their senses, it can be useful to turn to technology for help. Here, we present our research on the characterization of archaeological soils by spectrometric analyses, and we demonstrate the perspectives offered by robotics to excavate in fieldwork and to record the stiffness of the earth.
Forestry‐based carbon sequestration projects in Africa: Potential benefits and challenges
Authors: Jindal Rohit , Swallow Brent , Kerr John
Published: May 2008

Carbon sequestration through forestry and agroforestry can help mitigate global warming. For Africa, carbon sequestration also represents an opportunity to fund sustainable development through financial inflows. However, with a low share of global carbon trade, there are strong concerns that African countries are losing out on this valuable opportunity. Through a comprehensive review of 23 carbon sequestration projects across 14 countries, this paper discusses ways to overcome critical challenges to scale up carbon investments in Africa. These projects are expected to sequester 26.85 million tCO2 beyond the baseline situation. Within the continent, East Africa is the preferred destination for carbon investors. Most projects are non‐Kyoto compliant and represent voluntary emission reductions. While project benefits such as increased local incomes and improved natural resources are promising, there are concerns that conversion of grasslands into tree plantations can harm local ecosystems. Insecure land tenure constrains new investments and increases the risk that local communities will lose access to forests. Another challenge is that projects with smallholders have high transaction costs. These costs can be overcome by building strong community institutions and simplifying project guidelines. To attract more projects, African governments will need to build their capacity to identify relevant opportunities.
Building resilience to drought in desertification‐prone savannas in Sub‐Saharan Africa: The water perspective
Authors: Falkenmark Malin , Rockström Johan
Published: May 2008

Securing sustainable livelihood conditions and reducing the risk of outmigration in savanna ecosystems hosted in the tropical semiarid regions is of fundamental importance for the future of humanity in general. Although precipitation in tropical drylands, or savannas, is generally more significant than one might expect, these regions are subject to considerable rainfall variability which causes frequent periods of water deficiency. This paper addresses the twin problems of “drought and desertification” from a water perspective, focusing on the soil moisture (green water) and plant water uptake deficiencies. It makes a clear distinction between long‐term climate change, meteorological drought, and agricultural droughts and dry spells caused by rainfall variability and land degradation. It then formulates recommendations to better cope with and to build resilience to droughts and dry spells. Coping with desertification requires a new conceptual framework based on green‐blue water resources to identify hydrological opportunities in a sea of constraints. This paper proposes an integrated land/water approach to desertification where ecosystem management supports agricultural development to build social‐ecological resilience to droughts and dry spells. This approach is based on the premise that to combat desertification, focus should shift from reducing trends of land degradation in agricultural systems to water resource management in savannas and to landscape‐wide ecosystem management.
Protecting Biotechnology IPRs in Developing Countries: Simple Analytics of a Levy Solution
Authors: Cardwell Ryan , Kerr William A.
Published: May 2008

High transaction costs and an absence of institutional infrastructure in developing countries prevent comprehensive enforcement of intellectual property rights and generate obstacles to the adoption of genetically modified (GM) crop technology. Governments of developing countries that are members of the World Trade Organization are faced with two options when licensing GM crop technology: (1) attempt to regulate GM crops to the standards of the Agreement on Trade‐Related Aspects of Intellectual Property (TRIPS) or (2) allow a black market in GM seeds and risk trade retaliation from the GM innovator's host country through a TRIPS trade complaint. This paper develops a conceptual model that frames the adopting country's range of licensing options, including a new levy system, and derives welfare measures for each option. The model illustrates how a levy on GM technology can be a welfare‐increasing policy for developing countries, and the operation of a levy is discussed. The conceptual model is applied to Brazil's soybean market and quantitative economic surplus measures are estimated within a calibrated welfare model for a range of licensing scenarios. The model's results suggest that a levy may interfere with the long‐term prospects for innovators to collect monopoly rents in adopting countries.
Closed‐Form Mortgage Valuation Using Reduced‐Form Model
Authors: Liao Szu‐Lang , Tsai Ming‐Shann , Chiang Shu‐Ling
Published: May 2008

Valuing mortgage‐related securities is more complicated than valuing regular defaultable claims due to the borrower's prepayment behavior as well as the possibility of default. Some researchers use a structural‐form model to obtain the closed‐form formulas for the mortgage value. With this method, however, it is difficult to identify the critical region of early exercise. As an alternative, the reduced‐form model developed in this article is able to value the mortgage without setting boundary conditions, and it can thereby accurately handle the multidimensional space of correlated state variables. The purpose of this article is to derive a closed‐form solution of the mortgage valuation equation under a general reduced‐form model that embeds relevant economic variables. This new approach enables portfolio managers to undertake sophisticated portfolio optimization and hedging analyses. An implementation procedure for the model is also provided to demonstrate how the valuation framework can be utilized in practical applications.
REIT Dividend Determinants: Excess Dividends and Capital Markets
Authors: Hardin III William , Hill Matthew D.
Published: May 2008

The determinants of excess dividend payments above mandatory requirements in real estate investment trusts (REITs) are evaluated. Payment of excess dividends is related to factors associated with reduced agency costs, strong operating performance, the implementation of a stock repurchase plan and an ability to access short‐term bank debt. Recognizing that access to external capital is essential for long‐term growth, REITs manage dividend policy to allow for capital acquisition in the form of both equity and debt. The acquisition and use of short‐term bank debt provides REIT management flexibility in determining dividend policy.
Sustained, Natural Spawning of Southern Flounder Paralichthys lethostigma Under an Extended Photothermal Regime
Authors: Watanabe Wade O. , Carroll Patrick M. , Daniels Harry V. , Daniels Harry V.
Published: May 2008

Hormone‐induced spawning of southern flounder Paralichthys lethostigma has produced substantial numbers of viable eggs, but wide variations in fertilization and hatch rates have been reported. Recently, sustained natural spawning of southern flounder broodstock, without hormone induction, has been achieved in our laboratory. Adults (average weight = 1.12 kg; N= 25), including 6 captured as juveniles in 1993 and 19 captured as adults during September 1998, were stocked in two 4.8‐m3 controlled‐environment tanks in October 1998 and held under natural photothermal conditions until January 1999, when an artificial winter photo‐period of 10 L:14 D was initiated and then maintained through April 1999. Sex ratio was approximately 13 females:8 males:7 unknown. Natural spawning was observed in early December 1998 and increased in frequency to a peak in March 1999, before declining in late April. Water temperature ranged from 13.9 to 24.5 C during the spawning period. Natural spawnings over 142 d produced a total of 18.3 × 106 eggs, with a mean fertilization rate of 28.0% (range = 0–100%), yielding 4.94 × 106 fertilized eggs. The mean percentage of eggs that remained buoyant in full‐strength seawater (34 ppt) was 41.3% (0–98%), while hatching rate of buoyant eggs was 37.3% (0–99%) and survival of yolksac larvae to the first‐feeding stage was 30.2% (0–100%). Gonadal biopsies in late April identified six females from both tanks as probable spawners. A preliminary comparison suggests that natural spawning produced much larger numbers of viable eggs per female, with higher egg quality (i.e., fertilization and hatching success) than hormone‐induced spawning. In contrast to natural spawning, hormone‐induced strip‐spawning enabled timing of spawnings to be more precisely controlled. These results suggest that a combination of both natural and hormone‐induced spawning of photothermally conditioned fish will help produce the large numbers of eggs required to support commercial production.
The Relationship Between Vaccine Dose and Efficacy in Channel Catfish Ictalurus punctatus Vaccinated as Fry with a Live Attenuated Strain of Edwardsiella ictaluri (RE‐33)1
Authors: Wise David J. , Terhune Jeffery S.
Published: May 2008

Channel catfish Ictalurus punctatus were vaccinated at 12 d of age (post‐hatch) by a 2‐min bath immersion with attenuated Edwardsiella ictaluri RE‐33 at doses of 2.5 × 105, 2.5 × 106, and 2.4 × 107 colony‐forming units CFU/mL of water. Following vaccination, RE‐33 was recovered from a greater percentage of fry that were vaccinated at the high and intermediate doses compared to fry vaccinated at the lowest dose. Independent of dose, the greatest percentage of RE‐33 positive fry occurred between 1 and 6 d post‐vaccination with a significant decrease in positive fry observed on day 12. A significant increase in mortality occurred 6 to 12 d post‐vaccination in fry vaccinated at the highest dose. No differences in post‐vaccination mortalities occurred between the other treatments. Following virulent E. ictaluri challenge, mortalities of fish vaccinated at doses of 2.5 × 106 and 2.4 × 107 CFU/mL were significantly less than those of fish vaccinated at 2.5 × 105 CFU/mL and sham‐vaccinated control fish. These data show that vaccination with RE‐33 can offer protection against subsequent virulent E. ictaluri infection.
Effect of Low‐Temperature Incubation of Channel Catfish Ictalurus punctatus Eggs on Development, Survival, and Growth
Authors: Small Brian C. , Bates Terry D.
Published: May 2008

To determine whether the embryonic period of channel catfish lctalurus punctatus could be extended at low temperatures, fertilized channel catfish eggs were incubated at five constant water temperatures: 4, 11. 16. 21, and 26 C. Low‐temperature incubation of catfish eggs extended the embryonic period at 16 (244%) and 21 C (56%) when compared to the control hatchery incubation temperature of 26 C. All eggs incubated at 4 and 11 C died within 24–48 h. Developmental stage had a significant (P > 0.05) effect on percent hatch at 16, 21, and 26 C. Eggs held at 16 C prior to embryonic axis formation died within 48 h. Larvae from eggs hatched at 16 C were incompletely developed and died upon acclimation to 26 C for growth tests. Growth of fry reared at 26 C, following egg incubation at 21 C. paralleled that of fry from eggs incubated at 26 C. The underdevelopment of fry at 16 C combined with the significant effect of egg stage on survival at this temperature suggests that 16 C is below the lower thermal tolerance limit for normal development in this species. The period prior to the formation of the embryonic axis may be considered a vulnerable stage in channel catfish development. Increasing the embryonic period through low temperature incubation would increase the duration of juvenile availability for researchers and commercial operations.
Meiotic Gynogenesis Induction in Muskellunge Esox masquinongy by Thermal and Pressure Shocks
Authors: Garcia‐Abiado Mary Ann , Rinchard Jacques , Dabrowski Konrad
Published: May 2008

Mass production of fast‐growing, all‐female muskellunge Esox rnasquinongy by gynogenesis requires optimized techniques of preventing second polar body extrusion. Heat, cold, and pressure shocks were evaluated for their efficiency of doubling the maternal genome. Muskellunge eggs (20–40 g) were activated with 1 mL ultraviolet (UV)‐irradiated (1,248 J/ m2) heterologous sperm of yellow perch Perca flavescens. Survival and ploidy (by flow cytometry) were determined during the eyed‐stage. Cold shocks of 1.3 × 1 C were applied at 5 or 20 min after gamete activation with water (time of initiation, TI) for a duration of 150 min and pressure shocks of 48,263 or 55,158 kPa (7,000 or 8,000 psi, respectively) at a TI of 4 rnin for 12 min. These shock treatments resulted in 43.7–95.0% diploid gynogens with corresponding yield of diploid gynogen (percent diploid gynogens × total percent survival) of 2.6–11.I%. Cold shocks applied at TI of 5 or 20 min after activation resulted in statistically similar percent survival, percent diploid gynogens, and yield of diploid gynogens. Heat shocks of 31 × 0.1C applied at a TI of 5 to 15 min for a duration of 5 min resulted in 4.8–21.1% diploid gynogens with yields of 0.1–0.4%. Cold and pressure shocks have better potential than heat shock for preventing the second polar body extrusion. Muskellunge eggs activated with UV‐irradiated yellow perch sperm, but not exposed to shock, resulted in 100% haploids with survival of 2.3–5.8%. No viable embryos were produced from the hybrid cross between muskellunge and yellow perch, thus, all diploids produced after the shock treatments were unambiguous meiotic gynogens. Muskellunge eggs fertilized with fresh muskellunge sperm (controls) showed 60.4–64.0% survival to the eyedstage and 100% diploidy. Considering that the sex‐determining mechanism in muskellunge follows the WZ female, ZZ male system, future efforts should be directed to test the efficiency of cold and pressure shocks for mass‐producing gynogenetic super female (WW) muskellunge.
The Effect of Size and Diet on Gonad Production by the Chilean Sea Urchin Loxechinus albus
Authors: Olave Sergio , Bustos Eduardo , Lawrence John M. , Carcamo Pedro
Published: May 2008

Conadal production was studied in Loxechinus albus (Molina, 1782) maintained in cages suspended from a long‐line in the Estero Castro, Chiloé for 3 mo during the austral summer. The sea urchins were fed either an artificial diet or a natural diet consisting of the macroalgae Macrocystis pyrifera and Ulva sp. Both diets were tested for four size ranges: 40–45, 50–55, 60–65 and 70–75 mm diameter. For all four size ranges, highest gonad production was with the artificial diet. Gonad production was greatest in the 40–45 mm individuals with an increase of about 1,400% and 750% in the wet weight of gonads in individuals fed the artificial and natural diet, respectively. With the three other size ranges, the increase was nearly 100% with the artificial diet and nearly 0% with the natural diet The gonad index showed similar patterns, being highest in the smallest individuals. Small individuals fed the artificial diet would provide the most cost effective aquaculture as production is best. It is not necessary to grow L. albus to the minimal legal size for fisheries (70‐mm diameter) for cost effective gonad production.
Evaluation of Seven Algal Diets for Spat of the Pacific Scallop Argopecten ventricosus
Authors: Lora‐Vilchis Ma. Concepcioan , Doktor Natalia
Published: May 2008

The nutritive value of Isochrysis galbana (Tahitian), Chaetoceros calcitrans, Chaetoceros muel‐leri. and their bi‐ and trialgal combinations for Pacific scallop Argopecten ventricosus spat culture was studied. Ingestion rate, growth, survival, and biochemical composition were the variables evaluated. Growth results showed C. calcitrans and I. galbana + C. calcitrans diets have the best nutritive values. Poorest results were obtained with I. galbana diet. The acceptability and a high lipid content of C. calcitrans could explain the good results of C. calcitrans and I. galbana + C. calcitrans diets along with a better balanced diet effect in the bialgal mixture. The low growth of the scallops using the C. calcitrans + C. muelleri diet, despite the high ingestion rate, is explained by a low energy content and an unbalanced nutrient supply. The gross biochemical composition of the diets did not show a clear relationship to spat gross biochemical composition.
Reproductive Performance of Male Argentine Red Shrimp Pleoticus muelleri Bate (Decapoda, Penaeoidea) in Culture Conditions
Authors: Díz Ana Cristina , Gimenez Analí V. Fernández , Harán Nora S. , Fenucci Jorge L.
Published: May 2008

Spermatophore and sperm quality of male Argentine red shrimp Pleoticus muelleri held under laboratory conditions was evaluated using compound spermatophore weight, sperm count and percentage of live sperm as indicators. Thirty‐seven males of S to 20 g wet weight were held indoors in a 3‐m diameter circular fiberglass tank for 45 d. They were fed fresh squid, clam and pelletized diet. Spermato‐phores were obtained by manual ejaculations. Four shrimps were re‐ejaculated to verify the subsequent spermatophore regeneration. Spermatophore mean weights were significantly lower for 5–10 g males than for 15–20 g males (r= 0.998) (P < 0.05). There were no significant differences in sperm count and percent live sperm among the different weight classes (5–15 g, 15–20 g, 20–25 g). The sperm count varied from 2.22 to 5.62 million. No change in sperm quality was seen in re‐ejaculated individuals. During the first 2 wk of the experiment, the spermatophores exhibited healthy morphology and colour; by the fifth week evidence of spermatophore deterioration was apparent. Despite the degree of melanization, sperm quality was not affected and the high variability in sperm count indicated that the artificial ejaculation is adequate in this species.
Effects of Diet and Water Source on the Nursery Production of Pacific White Shrimp Litopenaeus vannamei
Authors: Otoshi Clete A. , Montgomery Anthony D. , Look Antony M. , Moss Shaun M.
Published: May 2008

Penaeid shrimp reared in eutrophic pond water grow significantly faster than shrimp in clear well water, and this growth enhancement is especially pronounced in postlarval shrimp. The objective of this study was to determine if the nutritional benefits of pond water could supplement a lower protein feed for postlarval Pacific white shrimp Litopenaeus vannamei. Sixteen 230‐L tanks were stocked with 10‐d postlarvae at a density of 350 shrimp/tank. Four treatments (four replicates/treatment) were tested for 6 wk and consisted of: 1) shrimp grown in well water and fed a commercially available 45%‐protein feed (W/45); 2) shrimp grown in pond water and fed the same 45%‐protein feed (P/45); 3) shrimp grown in well water and fed a commercially available 52%‐protein feed (W/ 52); and 4) shrimp grown in pond water and fed the same 52%‐protein feed (P/52). At the end of the experiment. mean weight gain (± SE) for shrimp in pond water (1.85 ± 0.03 g) was significantly greater (P > 0.0001) than shrimp in well water (0.98 ± 0.10 g). Mean weight gain for shrimp fed the 52%‐protein feed (1.56 ± 0.13 g) was significantly greater (P > 0.0001) than shrimp fed the 45%‐protein feed (1.26 ± 0.20 g). In addition, there was a significant interaction effect between water source and feed (P > 0.0001). Mean weight gain for shrimp in the W/52 treatment (1.23 ± 0.04 g) was 68% greater than shrimp in the W/45 treatment (0.73 ± 0.03 g). However, mean weight gain for shrimp in the P/52 treatment (1.90 ± 0.03 g) was only 5% greater than shrimp in the P/45 treatment (1.80 ± 0.04 g). These results suggest that organically rich pond water provides postlarval shrimp with sufficient nutrients to compensate for nutritional deficiencies associated with a lower protein feed.
Surgical treatment of carpal flexural deformity in 72 horses
Authors: Charman RE , Vasey JR
Published: May 2008

Carpal flexural deformities (CFD) are frequently encountered in the horse, with both congenital and acquired forms described. The success of surgical correction of CFD, both in terms of the ability to achieve a straight palmar carpal angle and the impact on future athletic performance, requires further investigation.

Objective  To report the surgical management and outcome of treatment of flexural deformity of the carpus in 72 horses up to 12 months of age.

Method  Information was obtained from the medical records of horses surgically treated for CFD and through follow‐up contact with owners. At the time of examination each case was graded on the severity of the flexural deformity as grade 1, 2, or 3, in order of ascending severity. Surgical treatment consisted of tenotomy of the ulnaris lateralis and flexor carpi ulnaris muscles. Re‐assessment of the palmar carpal angle was made in the immediate postoperative period and again from at least 8 months after surgery via telephone contact with owners and/or breeders. A successful outcome was defined as achievement of a straight palmar carpal angle. Long term outcome was assessed in terms of fulfilment of intended use for horses reaching 3 years of age at the time of the study.

Results  A total of 135 surgical procedures were performed on 72 horses. A successful outcome was recorded in 111 limbs (82%). Excluding cases lost to follow‐up, surgical correction was more successful in restoring a straight palmar carpal angle in grade 1 limbs (25/25, 100%) compared to grade 2 limbs (78/87, 89%) and grade 3 limbs (8/14, 57%). For those horses that had reached 3 years of age, 26 of 36 Thoroughbreds started in a race (72%) and 12 of 14 non‐Thoroughbreds fulfilled their intended use (86%).

Conclusion  Tenotomy of the ulnaris lateralis and flexor carpi ulnaris tendons for treatment of grade 1 and 2 CFD's has an excellent prognosis for restoration of a straight palmar carpal angle and for intended athletic pursuit of the horse. In cases of grade 3 CFD, the prognosis following surgery is guarded, especially in neonates. Horses treated in this study were up to 12 months of age, indicating that this deformity may not always be self‐limiting as previously thought, and treatment may be required for successful resolution of flexural deformity of the carpus in older animals. The results of this study will help veterinarians to make recommendations regarding the surgical treatment of CFDs.
Detection of Mycoplasma pulmonis in Laboratory Rats and Technicians
Authors: Ferreira J. B. , Yamaguti M. , Marques L. M. , Oliveira R. C. , Neto R. L. , Buzinhani M. , Timenetsky J.
Published: May 2008

Five species of mycoplasma are associated with several rat diseases. Mycoplasma pulmonis is the most important and most studied, possibly causing disease in rats and undermining the validity of laboratory experiments. M. pulmonis was isolated in 144/240 laboratory rats and identified by PCR in 155/240. This species was also detected in 12 human individuals (technicians of a laboratory animal house hold) in contact with these rats. The results were confirmed by sequencing of DNA products. Mycoplasma species are host specific; however, M. pulmonis was identified in humans, suggesting a case of unspecific colonization. Statistical analysis shows a greater risk for M. pulmonis colonizing individuals who are exposed to infected rats in animal facilities than individuals who do not. The detection of M. pulmonis in humans indicates a new status for this mollicute mycoplasmas in animal‐holding facilities.
Characterization of Virulence Properties of Listeria monocytogenes Serotype 4b Strains of Different Origins
Authors: Werbrouck H. , Botteldoorn N. , Ceelen L. , Decostere A. , Uyttendaele M. , Herman L. , Van Coillie E.
Published: May 2008

In this study, the virulence heterogeneity of Listeria monocytogenes serotype 4b strains of different origins was analysed on different levels. On one hand, the survival of L. monocytogenes strains in synthetic gastric fluid was studied. On the other hand, the pathogenic potential of strains with different inlB expression levels was analysed in an A/J mouse model for gastrointestinal listeriosis. Differences in survival capacity in gastric fluid and in in vivo virulence potential were observed between the tested strains. No clear correlation between the origin and the obtained data could be made. However, these results confirm the existence of heterogeneity in virulence potential of L. monocytogenes serotype 4b strains.
Human Serum Contains a Protease That Protects against Cytotoxic Activity of
Bacillus anthracis
Lethal Toxin In Vitro
Authors: Goldman David L. , Zeng WangYong , Rivera Johanna , Nakouzzi Antonio , Casadevall Arturo
Published: May 2008

The role of innate immunity in the host response to
Bacillus anthracis
is poorly understood. We found that normal human serum contains an antitoxin mechanism that is capable of protecting macrophages in vitro from
B. anthracis
lethal toxin-mediated killing. This protective activity was limited to defined amounts of toxin and was lost by heat treatment or serum dilution. Some person-to-person variation in the protective activity of serum was noted, especially with higher concentrations of lethal toxin. A similar protective activity was found in murine serum, though human serum consistently neutralized more toxin than did murine serum. The protective activities of both murine and human sera correlated with cleavage of the protective antigen into two fragments with approximate molecular sizes of 20 and 50 kDa that were recognized by the monoclonal antibodies 7.5G and 10F4, respectively. This pattern of fragmentation is consistent with cleavage at multiple sites, including the furin-susceptible site. Cleavage was abolished by heat treatment and calcium chelation. These findings highlight a potential role for serum proteases in protection against the lethal toxin of
B. anthracis
.
Development and Characterization of an Equine Infectious Anemia Virus Env-Pseudotyped Reporter Virus
Authors: Tallmadge R. L. , Brindley M. A. , Salmans J. , Mealey R. H. , Maury W. , Carpenter S.
Published: May 2008

We developed a replication-defective reporter virus pseudotyped with the envelope glycoprotein of equine infectious anemia virus (EIAV). The in vitro host range and neutralization phenotype of EIAV Env-pseudotyped virus were similar to those of replication-competent virus. An EIAV Env pseudovirus will improve antigenic characterization of viral variants and evaluation of lentivirus vaccines.
Multiplex PCR and Oligonucleotide Microarray for Detection of Single-Nucleotide Polymorphisms Associated with
Plasmodium falciparum
Drug Resistance
Authors: Zhang Guo Qing , Guan Ya Yi , Sheng Hai Hui , Zheng Bin , Wu Song , Xiao Hua Sheng , Tang Lin Hua
Published: May 2008

Drug resistance in
Plasmodium falciparum
is a serious public health threat in the countries where this organism is endemic. Since resistance has been associated with specific single-nucleotide polymorphisms (SNPs) in parasite genes, molecular markers are becoming useful surrogates for monitoring the emergence and dispersion of drug resistance. In this study, a multiplex PCR (mPCR) and oligonucleotide microarray method was developed for the detection of these SNPs in genes encoding chloroquine resistance transporter (Pf
crt
), multidrug resistance 1 (Pf
mdr1
), dihydrofolate reductase (Pf
dhfr
), dihydropteroate synthetase (Pf
dhps
), and ATPase 6 (Pf
ATPase6
) of
P. falciparum
. The results show that DNA microarray technology, combined with mPCR, is a promising and time-saving tool that supports conventional detection methods, allowing sensitive, accurate, simultaneous analysis of the SNPs associated with drug resistance in
P. falciparum
.
Occult Hepatitis C Virus Infection Revisited with Ultrasensitive Real-Time PCR Assay
Authors: Halfon Philippe , Bourlière Marc , Ouzan Denis , Sène Damien , Saadoun David , Khiri Hacène , Pénaranda Guillaume , Martineau Agnes , Oulès Valérie , Cacoub Patrice
Published: May 2008

Occult hepatitis C infection is regarded as a new entity that should be considered when diagnosing patients with a liver disease of unknown origin. Using an ultrasensitive real-time PCR assay, we demonstrated that occult hepatitis C virus (HCV) infection cannot be found in peripheral blood mononuclear cells of patients with cryptogenic liver diseases, HCV-associated systemic vasculitis, or connective tissue diseases. The significance of such occult infection must be elucidated.