bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors modifying stress from adverse effects of immunosuppressive medication in kidney transplant recipients
Authors: Rosenberger Jaroslav , Geckova Andrea Madarasova , van Dijk Jitse P , Roland Robert , van den Heuvel Wim JA , Groothof f Johan W
Published: January 2005

Abstract:  Introduction:  The adverse effects of immunosuppression appear in the majority of patients with a negative impact on morbidity, mortality and quality of life. The group of adverse symptoms manifested as changes in appearance, mood and energy are often more stressful than serious metabolic changes because of their direct negative influence on patients’ well‐being. The aim of this study is to explore the adverse symptoms of immunosuppressive medication which are the most stressful for transplanted patients, and which are the modifying factors.

Patients and methods:  A total of 157 adult kidney transplant recipients from two transplant centres in Slovakia with a functioning graft transplanted <7 yr ago were examined. Patients participated in an interview focusing on stress from adverse effects, and their education and social support. Medical records were searched for information about immunosuppression protocols, dialysis treatment before transplantation, type of received organ and period after transplantation. The effect of the selected variables on the total score for stress from adverse effects was tested using ANOVA. The effect of the selected factors on stress from each single adverse effect was explored using t‐test and ANOVA.

Results:  The most stressful symptoms were pain, weakness, weight gain, facial changes, depression and anxiety. The mean value of the total score for stress from adverse effects was 8.03 ± 6.53 (minimum 0, maximum 30, range: 0–64), indicating low stress. Women and patients with lower education significantly more often felt the adverse effects of immunosuppression as stressful (p < 0.001 and p < 0.05, respectively). Age, social support, dialysis modality before transplantation, time from transplantation and type of immunosuppressive treatment did not affect the total score for stress from adverse effects. However, variables that were not significant in the overall score reached significance in some symptoms.

Conclusions:  Women and patients with lower education significantly more often felt the adverse effects of immunosuppression as stressful; in a more detailed analysis the use of new drugs was connected with less stress in some symptoms. The use of these drugs can improve life quality for transplant recipients, decrease non‐compliance, and thus prevent graft loss.
Laparoscopic donor nephrectomy vs. open live donor nephrectomy: a quality of life and functional study
Authors: Buell Joseph F , Lee Lucy , Martin Jill E , Dake Natalie A , Cavanaugh Teresa M , Hanaway Michael J , Weiskittel Pat , Munda Rino , Wesley Alexander J , Cardi Michael , Ram Peddi V , Zavala Edward Y , Berilla Elaine , Clippard Marketa , Roy First M , Steve Woodle E
Published: January 2005

Abstract:  Background:  Few studies have compared the quality of life (QoL) and functional recuperation of laproscopic donor nephrectomy (LDN) vs. open donor nephrectomy (ODN) donors. This study utilized the SF‐36 health survey, single‐item health‐related quality of life (HRQOL) score, and a functional assessment questionnaire (‘Donor Survey’).

Methods:  Questionnaires were sent to 100 LDN and 50 ODN donors. These donors were patients whose procedures were performed at The University Hospital and The Christ Hospital in Cincinnati, Ohio.

Results:  A total of 46 (46%) LDN and 21 (42%) ODN donors returned the completed surveys. The demographics of the two groups were similar. LDN patients reported a more rapid return to 100% normal health (69 vs. 116 d; p = 0.24), part‐time work (21.9 vs. 23.2 d; p = 0.09), and necessitated fewer physician office visits post‐operative (2.8 vs. 4.4; p = 0.01). ODN patients reported shorter duration of oral pain medication use (13.4 vs. 7.2 d; p = 0.02). However, a greater number of ODN patients reported post‐surgical chronic pain (3 vs. 6; p < 0.05) and hernia (0 vs. 2; p = 0.19). The overall QoL for both groups was comparable with the general USA population.

Conclusions:  The results of this study support the decisions of many kidney transplant centers to adopt LDN programs as standard of care.
A prospective 3‐yr evaluation of tacrolimus‐based immunosuppressive therapy in immunological high risk renal allograft recipients
Authors: Zaltzman Jeffrey S. , Boucher Anne , Busque Stephan , Halloran Phillip F. , Landsberg David N. , McAlister Vivian C. , Russell David , Shoker Ahmed , Shapiro Jean , Tchervenkov Jean I. , Ferguson Ralph
Published: January 2005

Abstract: Background: There have been no published data on use of the the newer immunosuppressants tacrolimus and mycophenolate mofetil (MMF) in high immunological risk renal transplantation. We therefore undertook a prospective study to systematically assess outcomes using these agents as part of an aggressive immunosuppressive regimen.

Methods: Fifty‐nine high‐risk renal allograft recipients were enrolled at 10 Canadian sites and given a regimen of: a biological induction agent, tacrolimus, MMF, and corticosteroids. Patients included 10 (17%) who had lost a previous graft to rejection <1 yr, 31 (53%) with a current panel reactive antibody (PRA) >30%, 47 (80%) with a historic PRA >50%, four (7%) who had a positive historical T‐cell crossmatch with the current donor, and six (10%) with a current positive B‐cell crossmatch. The mean peak PRA was 76 ± 33%.

Results: The estimated 3‐yr Kaplan–Meier patient and graft survival estimates were 89% and 75%, respectively. There were nine graft losses other than deaths with a functioning graft, of which six were preceded by delayed graft function (p = 0.01,χ2). Sixteen (27%) recipients experienced at least one episode of biopsy‐confirmed acute rejection. Infections included cytomegalovirus in 16 patients, eight of whom had tissue‐invasive disease. Only one malignancy occurred.

Conclusions: The immunosuppressive strategy investigated is effective and displays a satisfactory safety profile in high immunological risk renal allograft recipients.
Organizational Prospects, Influence Costs, and Ownership Changes
Authors: Meyer Margaret , Milgrom Paul , Roberts John
Published: January 2005

We augment efficiency‐based theories of ownership by including influence costs. Our principal conclusion is that the prospect of organizational decline and layoffs creates additional influence costs in multiunit organizations that would be absent if there was no prospect of layoffs and would be lessened or eliminated in focused organizations. This helps explain the tendency of firms to divest poorly performing units, as well as the pattern of sales of such units to firms already in businesses related to that of the divested unit.
Information, Control, and Organizational Structure
Authors: Baron David P. , Besanko David
Published: January 2005

This paper investigates how a designer of an organization (referred to as the regulator) should organize a production activity in which two different units produce components and where each unit has private information about its costs. Three organizational structures are analyzed. In the first (informational consolidation), the regulator contracts with a consolidated unit that produces both components. In the second (informational decentralization), the regulator independently contracts with the producer of each component. In the third (informational delegation), the regulator contracts with one of the units, which in turn subcontracts with the other. In each case, the regulator's optimal mechanism consisting of payment and output schedules is fully characterized. Informational consolidation and informational decentralization yield different output schedules. Under informational decentralization, the optimal output schedule may not depend on the sum of the marginal costs of each component, but when it does, the regulator strictly prefers informational consolidation to informational decentralization. Informational delegation is shown to be equivalent to informational decentralization when the regulator can observe the contracting between the units.
Strategic Product Choiceand Niche Markets
Authors: Pepall Lynne
Published: January 2005

This paper presents a model of strategic product choice when consumer preferences combine features of both horizontal and vertical product differentiation. Consumers disagree on what amount of a “special” characteristic makes for a better product, but those who prefer more of this attribute are willing to pay more for it. Within this demand structure, I examine the advantages of first‐mover firms. I find that such firms typically do best in markets where the maximum degree of product differentiation is limited by preferences rather than technology. These are “niche markets”. Follower firms do better in markets in which the range of preferences is broad relative to the span of feasible goods.
A MODEL OF SEARCH AND SHOPPING BY HOMOGENEOUS CUSTOMERS WITHOUT PRICE PRECOMMITMENT BY FIRMS
Authors: Daughety Andrew F.
Published: January 2005

Price setting by firms and search by customers is analyzed, relaxing two basic attributes of most search models: price precommitment and agent heterogeneity. Customers are characterized by individual demand functions for a homogeneous good and can choose to employ a threat to search. Firms noncooperatively make pricing decisions by using the individual demand curves under conditions of constant marginal cost. Firms adopt pricing rules that optimally respond to customer search histories. Bargaining power is endogenously assigned. Firms know their common marginal cost; customers, the cost distribution. The unique separating equilibrium is characterized by a lumpy distribution of prices and by heterogeneous shopping behavior by customers giving rise to “shoppers” and “nonshoppers”
PriceCompetitionWhenConsumersareUncertainAboutWhichFirmSellsWhichQuality
Authors: Gabszewicz Jean J. , Grilo Isabel
Published: January 2005

In this paper we analyze the properties of price equilibria in a duopoly market where firms sell vertically differentiated products, consumers being uncertain about which firm sells which quality. Both existence and properties of price equilibria are characterized by the beliefs of the consumers' population about the distribution of quality between firms.
A Reviewof Dixitand Nalebuff'sThinking Strategically: The Competitive Edgein Business, Politics, and Everyday Life
Authors: Brandenburger Adam
Published: January 2005

Thinking Strategically: The Competitive Edge in Business, Politics, and Everyday Life, by Avinash Dixit and Barry Nalebuff
A Theory of the Distribution of Underpriced Initial Public Offers by Investment Banks
Authors: Fulghieri Paolo , Spiegel Matthew
Published: January 2005

It is well documented that a firm may choose to offer underpriced securities in an initial public offer. An open question is why investment banks do not retain underpriced offers in their portfolio. We argue that the distribution of underpriced securities allows banks of high qualify to signal their value to their customers, promoting in this way their other product lines. We show that the total dollar value of underpriced securities distributed (rather than the percentage value) acts as the signal. We also find that, all else equal, larger customers and those with more elastic demand functions receive n larger total dollar value of underpricing.
Financial Distress and Optimal Capital Structure Adjustments
Authors: Heinkel Robert , Zechner Josef
Published: January 2005

We show that asymmetric information may prevent firms with pure discount bonds from renegotiating their capital structure prior to the maturity of the debt, although this would increase the value of the firm when its prospects are poor. This inefficiency can be reduced if the firm issues debt with a risky intermediate debt payment, such as a coupon or a sinking fund payment. We also demonstrate that bankruptcy institutions leading to deviations from absolute priority can improve the timing of recapitalizations by financially distressed firms. Finally, we show that, under certain conditions, the optimal capital structure adjustment during financial distress consists of a convertible debt‐for‐straight debt swap.
Refusals to Deal, Price Discrimination, and Independent Service Organizations
Authors: Chen Zhiqi , Ross Thomas W.
Published: January 2005

A number of recent Canadian and U.S. antitrust cases have involved allegations that manufacturers of durable products have refused to supply parts to independent service organizations, apparently to monopolize the market for repairs of their products. This paper provides a theory of these strategies and considers the welfare implications of judicial orders to supply. The refusals here are seen as necessary to protect manufacturers' program of price discrimination: Expensive repairs represent a way to select high‐intensity, high‐value users and charge them more. In addition to the usual ambiguity associated with the welfare effects of prohibitions of price discrimination, forcing competition in repairs can have the further damaging effect of reducing social welfare by inducing manufacturers to lower product quality.
Choice of Treatment Intensities by a Nonprofit Hospital Under Prospective Pricing
Authors: Rogerson William P.
Published: January 2005

Under prospective pricing, payers for health care essentially use price regulation of hospitals as a way of indirectly regulating the provision of treatment intensity. This paper presents a theory of how a nonprofit hospital selects treatment intensities for its products given the payer's choice of prices and then determines how the payer should select prices in light of this theory. The main result is that, in equilibrium, the ratio of price to marginal cost will vary across products inversely with the elasticity of demand with respect to treatment intensity. This means that, generally, the hospital will earn positive (negative) accounting profit on products with low‐(high‐) intensity elasticities of demand.
Excessive Investment in Hospital Capacities
Authors: Gal‐Or Esther
Published: January 2005

In the present study I identify an inherent characteristic of health care markets that may lead to excessive investment by hospitals even when compensated according to a prospective reimbursement rule. It is demonstrated that the stochastic nature of the demand for medical services combined with the lumpiness of investment decisions may give rise to excessive investment when multiple hospitals select independently their levels of capacities. The source for the excessive incentives to invest is the difficulty of one hospital to internalize properly the externality generated by its investment decisions. Such an externality arises because when one hospital expands its capacity, it is more likely to be able to serve not only patients residing in its region but patients residing in neighboring regions as well.
Payer Competition and Cost Shifting in Health Care
Authors: Glazer Jacob , McGuire Thomas G.
Published: January 2005

This paper studies a model in which two payers contract with one hospital. True costs per patient are not a possible basis for payment, and contracts can only be written on the basis of allocated cost. Payers choose a contract that is fully prospective or fully based on cost allocation, or a payment scheme that would give some weight to each of these two. We characterize the payers'equilibrium contracts arid show how in equilibrium hospital input decisions are distorted by the payers’ incentives to engage in cost shifting. Two cost‐shifting incentives work in opposite directions, and equilibrium can be characterized by too little or too much care relative to the socially efficient level.
Designing Optional No‐Fault Insurance Policies for Health Care Systems
Authors: Sappington David E. M.
Published: January 2005

Legislation to create optional no‐fault insurance (ONFL) programs has recently been enacted in Florida and Virginia. ONFI programs provide compensation to patients when certain medical complications arise, provided the patient agrees not to sue the doctor for additional damages. The optimal design of ONFI programs is explored in this paper, focusing on the incentive effects of ONFI programs. The question of whether ONFI programs should be funded entirely by participating doctors, or whether social subsidies are optimal, is examined.
Local Hospital Competition in Large Metropolitan Areas
Authors: Manheim Larry M. , Bazzoli Gloria J. , Sohn Min‐Woong
Published: January 2005

This paper uses origin‐destination data to define geographic local hospital markets in large metropolitan statistical areas (MSAs). Results support past findings of service rather than price competition, with negative‐cost Herfandahl‐Hirschman indexes relationships at the market level (and sub‐MSA level) and with profit margins negatively related to hospital market competition. The effects of total (direct plus indirect) market competition are unchanged between 1983 and 1988, precisely estimated, robust to estimation techniques, and unaffected by whether the number of direct competitors is included as an explanatory variable.
Contracts and Specific Investment: An Empirical Test of Transaction Cost Theory
Authors: Lyons Bruce R.
Published: January 2005

Empirical work has failed to keep pace with recent advances in transaction cost theory and the theory of contract. The first econometric analysis of its kind is reported by using a new data set of small subcuntractors making specific inputs for customers in the engineering industry. The use of formal contracts is found to be strongly associated with specific investment and other variables measuring technological complexity and vulnerability to potential opportunism by customers. Furthermore, despite typically long‐term relationships, over half of subcontractors avoid making efficient, specific investments. Overall, we find strong support for the transaction cost theory of contracts.
Economic Analysis and Management Strategy: A Survey Continued
Authors: Spulber Daniel F.
Published: January 2005

I present an integrated survey of management strategy, which examines organizational design, competitive strategy, and public policy considerations. In addition, 1 offer suggestions on how economic analysis can be applied in unifying and developing management strategy as a field of study.
A Review of Milgrom and Roberts'sEconomics, Organization and Management
Authors: Gifford Sharon
Published: January 2005

Books reviewed in this article:

Economics, Organization and Management, by Paul Milgrom and John Roberts
Firm Growth and Survival: Does Ownership Structure Matter?
Authors: Kamshad Kimya M.
Published: January 2005

The publication of the passive learning model of Jovanovic and subsequently the active exploration model of Ericson and Pakes led to a resurgence in research on firm growth and survival. Empirical work measuring the relationship of growth and survival relative to size and age uncovered a number of strong regularities, consistent with the new theoretical models and also with a rather broad class of models of which the above represent special cases. But recent theoretical work has shown that when the learning models are applied to the special case of the labor managed firm, most of the sharp empirical predictions derived for profit maximization are rendered indeterminate. Given the impact of ownership structure on the theoretical results of the learning models, we use a dataset of French producer cooperatives to determine whether firms of different ownership structures actually have substantially different growth and survival patterns. We find that French cooperatives survive and grow in very much the same way as has been found for U.S. firms, suggesting that the empirical regularities previously uncovered hold for a much broader class of firms. We are left to conclude that the underlying empirical growth and survival relationships continue to hold for firms with sharply differing ownership structures, and the theoretical models are attempting to explain these broad‐based relationships by means of overly specific modeling.
Usage Heterogeneity and Extended Warranties
Authors: Padmanabhan V.
Published: January 2005

The role of product warranty in segmentation of consumer durable product markets is highlighted. I demonstrate that consumer moral hazard and heterogeneity in product usage create variation in the valuation of product warranties by the different segments in the market. In this context, the firm, by offering a self‐selecting menu of base warranty and extended warranties, satisfies the warranty demands of the various segments of the population. The consumer choice behavior prediction of the theory with regard to extended warranty is empirically validated with data from a survey of new car buyers.
Must Sell
Authors: Cabral Luís , Sákovics József
Published: January 2005

Why are moving sales a successful and widespread phenomenon? How can it be optimal for a seller to disclose her low valuation for the item to be sold? We propose an explanation based on the “lemons problem” in bargaining with asymmetric information about quality. Disclosing a low valuation signals that there are significant gains from trade, so that trade takes place when it wouldn't otherwise, and all agents are made better off.
Marketing Channels and the Durable Goods Monopolist: Renting versus Selling Reconsidered
Authors: Purohit Devavrat
Published: January 2005

Research on durable goods has shown that because of a time inconsistency problem, a monopolist manufacturer prefers to rent rather than sell its product. We reexamine the relative profitability of renting versus selling from a marketing perspective. In particular, using a simple linear demand formulation, we assume a durable goods monopolist has to use downstream intermediaries to market its product. In contrast to the case of an integrated monopolist, we find that when the monopolist has to rely on intermediaries, then it prefers to go through an intermediary that sells rather than one that rents its product. Similarly, the intermediary that sells the product is more profitable than the intermediary that rents the product. However, if the monopolist can commit to a set of prices, then the intermediary that rents is more profitable than the intermediary that sells.
Organizational Diseconomies of scale
Authors: McAfee R. Preston , McMillan John
Published: January 2005

Private information creates a cost of operating a hierarchy, which becomes larger as the hierarchical distance between the information source and the decision maker increases. When information about a firm's capabilities is dispersed among the individuals in the firm, production is inefficient even though everyone behaves rationally. Because hierarchies need rents in order to function, a firm with a long hierarchy may not be viable in a competitive industry.
ProductRivalry with multipleStrategic weapons:anAnalysis of price and advertisingCompetition
Authors: Slade Margaret E.
Published: January 2005

A dynamic model of product rivalry is developed for a market in which firms choose price and advertising intensity. The model, a state‐space game, is implemented using data that consist of weekly price, sales, and promotional activity for four brands of saltine crackers sold by four chains of grocery stores in a small town. A number of questions can be asked of this data. First, is advertising predatory (merely changing market shares) or cooperative (shifting out market demand)? Second, are price and advertising own and cross‐strategic complements or substitutes? And finally, do investments in stocks of goodwill and in price reductions make firms tough and aggressive or soft and accommodating?
Why Retailers Sell Private Labels
Authors: Mills David E.
Published: January 2005

This paper interprets private label marketing as a retailer instrument for overcoming the double‐marginalization problem inherent in the distribution of well‐known manufacturer brands. Retailers with some degree of market power carry private label substitutes for popular national brands in order to capture more profit from the vertical structures they share with brand manufacturers. The net effect of private label marketing is to improve the performance of distribution channels. After presenting a formal model and deriving analytical results, the paper gathers some empirical evidence that supports these results.
The Acquisition of Restructured Firms: An Illustration of Market Discipline?
Authors: Seward James K. , Walsh James P.
Published: January 2005

We examine the relationship between chief executive officer (CEO) compensation and acquisition activity subsequent to corporate restructurings in a sample of 152 firms created by a voluntary corporate spin‐off. We also investigate the linkage between these relationships and the stock market reaction to the initial restructuring announcements. Surprisingly, CEO wealth in the form of stock and options is strongly related to friendly and hostile acquisition activity, respectively. Moreover, the stock market appears to anticipate this subsequent acquisition activity. These results ask us to rethink our understanding of the motivational properties of equity ownership and the stock market's reaction to voluntary corporate spin‐off announcements.
Shareholder Activism, “Voluntary” Restructuring, and Internal Labor Markets
Authors: Garvey Gerald T. , Swan Peter L.
Published: January 2005

We model an internal labor market in which employee behavior and compensation are affected by the firm's financial position and the threat of hostile takeover or other exercise of shareholder “voice.” We show how good past performance can result in excessively generous promotion and pay decisions. While the threat of shareholder activism will remove this “slack,” activists optimally face a positive cost barrier, which in turn varies across firms. The cost barrier is higher when cooperation or “helping” between employees is more important, and is lower when employees receive efficiency wages due to an inability to “pay” for their jobs. Since the importance of helping is associated with pay compression and “flat” pay ladders, such firms should also exhibit a greater degree of management entrenchment.
Specialization, Option Demand, and the Pricing of Medical Specialists
Authors: Dranove David , White William D.
Published: January 2005

This paper discusses the supplier power of medical specialists. We argue that a combination of factors, including the structure of health care delivery, reimbursement systems, the presence of option demand, and high consumer switching costs, create circumstances in which medical specialists may be able to exercise significant seller power. We explore the implications of this for the pricing and organization of medical care.
Long‐Term or Short‐Term Managerial Incentive Contracts
Authors: Barcena‐Ruiz Juan Carlos , Espinosa Maria Paz
Published: January 2005

This paper deals with the strategic role of the temporal dimension of contracts in a duopoly market. Is it better for a firm to sign long‐term incentive contracts with managers or short‐term contracts? For the linear case, with strategic substitutes (complements) in the product market, the incentive variables are also strategic substitutes (complements). It is shown that a long‐term contract makes a firm a leader in incentives, while a short‐term contract makes it a follower. We find that, under Bertrand competition, in equilibrium one firm signs a long‐term contract and the other firm short‐term incentive contracts; however, under Cournot competition, the dominant strategy is to sign long‐term incentive contracts.
WageBargaining inIndustries withMarketPower
Authors: Jorge Padilla A. , Bentolila Samuel , Dolado Juan J.
Published: January 2005

We develop a game‐theoretic version of theright‐to‐managemodel of firm‐level bargaining where strategic interactions among firms are explicitly recognized. Our main aim is to investigate how equilibrium wages and employment react to changes in various labor and product market variables. We show that our comparative statics results hinge crucially on the strategic nature of the game, which in turn is determined by the relative bargaining power of unions and managers.
Histology and Ultrastructure of the Equine Lingual Tonsil. I. Crypt Epithelium and Associated Structures
Authors: Kumar P. , Timoney J. F.
Published: January 2005

The microstructural and ultrastructural features of the equine lingual tonsil were studied in five young horses. Located at the root of the tongue it presented an irregular surface with rounded elevations, numerous folds and crypts. Stratified squamous non‐keratinized epithelium lining its outer surface was modified by heavy infiltration of lymphoid cells to form reticular epithelium within the crypt. The latter implies a role in initiating and maintaining immune responses to incoming infectious agents and antigens. Lamellated structures resembling Hassall's corpuscle were observed towards the outer surface epithelium. Microplicae were visible by scanning electron microscopy on the surface of both the outer and reticular epithelia. No microvillus cells resembling M cells were observed. The stratum superficiale of the reticular epithelium showed strong affinity for Soybean (SBA), Phosphocarpus tetragonolobus 1 (WBA 1), Ulex europaeus (UEA) and Griffonia simplicifolia 1 isolectin‐B4 (GS1‐B4). The characteristic lectin binding patterns may be useful for embryological and microbiological investigations. Vimentin filaments were not detected consistent with absence of M cells. Mucus glandular acini in the deeper lamina propria mucosae contained glycogen, acidic, neutral and weakly sulphated mucopolysaccharides. Transmission electron microscopy revealed that the layers of the outer surface and reticular epithelia shared characteristic features except the stratum superficiale, which had nuclei of varying shapes and an abundance of cell organelles. A few mast cells with electron lucent granules and myelinated nerve fibres were localized in the deeper portion.
Anatomy of the Cranioencephalic Structures of the Camel (Camelus dromedarius L.) by Imaging Techniques: A Magnetic Resonance Imaging Study
Authors: Arencibia A. , Rivero M. A. , Gil F. , Ramírez J. A. , Corbera J. A. , Ramírez G. , Vázquez J. M.
Published: January 2005

The objective of this study was to define the anatomy of the cranioencephalic structures and associated formations in camel using magnetic resonance imaging (MRI). MR images were acquired in sagittal, transverse and oblique dorsal planes, using spin‐echo techniques, a magnet of 1.5 T and a standard human body coil. MR images were compared with corresponding frozen cross‐sections of the head. Different anatomic structures were identified and labelled at each level. The resulting images provided excellent soft tissue contrast and anatomic detail of the brain and associated structures of the camel head. Annotated MR images from this study are intended to be a reference for clinical imaging studies of the head of the dromedary camel.
Variation in the Boldness of Courting Sand Fiddler Crabs (Uca pugilator)
Authors: Pratt Ann E. , McLain Denson K. , Berry Allison S.
Published: January 2005

Individuals can express boldness in their readiness to resume courtship signaling following a perceived threat. The degree of boldness that is selectively favored depends on the magnitude of costs and benefits that may vary across time and space. We examined within‐ and between‐individual variation in the boldness of courting male sand fiddler crabs, Uca pugilator, across an entire breeding season at a South Carolina (USA) salt marsh where courtship is restricted to supratidal embankments. Boldness was assessed by the time to re‐emergence and the number of re‐emergences of males who were purposely startled into their breeding burrows once every 3 min for a total of five times. The two measures of boldness were significantly positively correlated. Courting males are on average bolder when their density is high and when tidal conditions correspond to peaks in the number of females moving over the embankment surface. Time to re‐emergence increases with successive startles although some males consistently re‐emerge faster than others. Large males are not bolder than small males. When male density is high, nearest neighbors frequently re‐emerge at the same time, suggesting that males cue on the responses of other nearby males, perhaps by assessing substrate vibration. This may reduce the chance of losing a potential mate to a local competitor.
Seasonal Variation in Mate Choice of Photinus ignitus Fireflies
Authors: Cratsley Christopher K. , Lewis Sara M.
Published: January 2005

Mate choice by either sex may vary with changes in the associated costs and benefits, determined by factors such as the availability of potential mates and variation in mate quality. We examined seasonal variation in operational sex ratio, courtship behavior, spermatophore mass, egg count, and the relationship between morphological traits and mating success in Photinus ignitus fireflies to determine if mate choice in either sex varied with the availability and relative reproductive investment of fertilizable females and sexually active males. Successfully mating males had larger lanterns than unsuccessful males when the operational sex ratio was male‐biased. In addition, female responsiveness to male signals increased as the number of courting males decreased, and male spermatophore mass decreased with body size across the mating season. Successfully mating females had larger body mass than unsuccessful females. Female body mass predicted egg count and female rejection by males increased as the season progressed and female size decreased. These results suggest that both male and female P. ignitus exhibit mate choice, and that such choice is influenced by seasonal variation in the abundance and quality of potential mates.
Evolution of Classical Polyandry: Three Steps to Female Emancipation
Authors: Andersson Malte
Published: January 2005

(Invited Article)

AbstractIn classical polyandry, sex roles are reversed and a female reproduces with several males, each of whom raises his offspring with little or no help from her. This mating system occurs in some fishes and birds, and it is of great interest in relation to parental investment, sex role and sexual selection theory. The evolution of classical polyandry, however, is debated and not well understood. It is here suggested to generally take place in three main steps. (1) First evolvesmale care for eggs, for reasons that differ between fishes and birds. (2) Second,a female becomes able to lay more eggs than a male can accommodate.This can happen, for example, by evolution of male pregnancy or smaller body size, or by female production of more or larger eggs, made possible by larger female body size or more food. Polyandry in several taxa is associated with shift to a habitat rich in food during the breeding season, to novel specialised foraging methods, or to both. A favourable food situation may be crucial for evolution of classical polyandry. (3) In step three,females compete to lay two or more clutches in sequence for different males. Successful polyandrous females obtain more offspring, spreading traits that enhance success in competition over males. Step three may be most likely in species with small body size, for reasons of reproductive constraints and seasonality. Evolution of classical polyandry appears to have followed these steps in shorebirds, coucals and pipefishes, but the reasons why certain species differ from their close phylogenetic relatives in being polyandrous are far from clear. Behavioural and ecological studies of additional species, and detailed phylogenies of taxa with diverse mating systems including polyandry, are needed for testing these ideas.
Influence of crop residue ration supplementation on the attainment of puberty and postpartum reproductive activities of Red Sokoto goats
Authors: Malau‐Aduli B. S. , Eduvie L. O. , Lakpini C. A. M. , Malau‐Aduli A. E. O.
Published: January 2005

The general objective of this study was to come up with an appropriate, affordable and locally available crop residue supplementation package that would enhance reproductive performance in small ruminants. Specifically, 28 Red Sokoto weaner does between 3 and 4 months of age weighing between 2 and 3 kg were used in the first experiment to determine the influence of crop residue supplementation on age and weight at puberty as determined by blood progesterone levels. In the second experiment, another 28 adult does (≥2 years old) of the same breed in the same flock with lactation numbers between 1 and 3 were used to determine the length of postpartum acyclic period. In both experiments, a 3 × 2 factorial experimental design comprising three dietary supplements (A, B, C) at two feeding levels (1% and 2% of body weight) fed in addition to a basal diet of Digitaria smutsii hay and natural pasture ad libitum with an unsupplemented negative control group (D) and four goats per treatment was utilized. In ration A, a conventional concentrate supplement consisting of maize, wheat offal, cottonseed cake and bonemeal was utilized; in rations B and C, the supplement consisted of guinea‐corn bran, cowpea husk and groundnut haulms; and maize offal, groundnut shells and groundnut haulms respectively. Unsupplemented (ration D) weaner does reached puberty at a later age and had lighter body weights than all the others. Weaner does on ration 2A (concentrate fed at 2% of body weight) attained puberty at the earliest age and heaviest body weight, although the age at puberty was not significantly different from those on rations 1A (concentrate fed at 1% body weight), 1C and 2C. Blood progesterone profiles before and after puberty ranged from 0.05 to 9.0 ng/ml, respectively, and was highest in does fed rations A and C and least in the unsupplemented does. The mean interval between kidding and initiation of ovarian activity was 54.28 ± 17.61 days and the mean interval between kidding and conception was 63.04 ± 25.34 days. Only 25% of the unsupplemented does conceived again during the period under study compared with 100% in rations 1A, 2A, 1C and 2C; 75% in ration 2B and 50% in ration 1B. It was concluded that implementation of supplementary feeding in the dry season improves reproductive performance in the Red Sokoto doe. Furthermore, ration C, a crop residue‐based ration, was a suitable dry season supplementation alternative to the expensive conventional concentrate ration for the smallholder goat farmer in the subhumid tropics of Nigeria.
Engaging Australian physicians in evidence‐based medicine: a representative national survey
Authors: Toulkidis V. , Donnelly N. J. , Ward J. E.
Published: January 2005

Aim: To assess Australian adult physicians’ views about evidence‐based medicine (EBM) and quality improvement (QI).

Background: Cross‐sectional postal survey of two hundred and forty‐four randomly selected Australian physicians (78.5% response rate).

Method: Physicians’ views about the promotion of EBM and QI and their impact on patient care, strategies to support better clinical practice and self‐reported understanding of EBM terms.

Results: Sixty‐eight per cent (95% confidence interval (CI): 62–74%) of physicians had a positive view of the current promotion of EBM in Australia. Significantly fewer (45%; 95% CI: 38–51%) were so positive about QI (P < 0.001). Although 74% (95% CI: 68–79%) indicated that EBM improves patient care, significantly fewer (46%; 95% CI: 40–53%) held this view with respect to QI (P < 0.001). Although 70% (95% CI: 64–76%) of physicians agreed they had adequate skills to search for evidence, significantly fewer (21%; 95% CI: 17–27%) agreed they had sufficient time to do so (P < 0.001). EBM skills were positively associated with involvement in teaching. Physicians were significantly more positive about approaches exclusive to themselves compared with those involving other disciplines.

Conclusions: Although Australian physicians have positive views of EBM, QI appears less well regarded. Initiatives to improve quality and safety that incorporate principles and language of EBM will likely be received better by physicians than isolated QI. Further enhancement of EBM requires concomitant attention to physician training, workplace infrastructure and supportive professional development. (Intern Med J 2005; 35: 9–17)
The Monty Hall Three Doors Problem
Authors: Puza Borek D. , Pitt David G. W. , O'Neill Terence J.
Published: January 2005

In this article, we study the Monty Hall three doors problem. A fully general solution and several new approaches are presented, including a Bayesian analysis.
Means and Variances without Calculus
Authors: Kinney John J.
Published: January 2005

This article gives a method of finding discrete approximations to continuous probability density functions and shows examples of its use, allowing students without calculus access to the calculation of means and variances.
A Comparison of Strategies for Playing Even Money Bets in Roulette
Authors: Croucher John S.
Published: January 2005

This article discusses some strategies for playing roulette, making use of the binomial distribution and Normal approximation.
Prostaglandin D2 mediates neuronal protection via the DP1 receptor
Authors: Liang Xibin , Wu Liejun , Hand Tracey , Andreasson Katrin
Published: January 2005

Cyclo‐oxygenases (COXs) catalyze the first committed step in the synthesis of the prostaglandins PGE2, PGD2, PGF2α, PGI2 and thomboxane A2. Expression and enzymatic activity of COX‐2, the inducible isoform of COX, are observed in several neurological diseases and result in significant neuronal injury. The neurotoxic effect of COX‐2 is believed to occur through downstream effects of its prostaglandin products. In this study, we examined the function of PGD2 and its two receptors DP1 and chemoattractant receptor‐homologous molecule expressed on Th2 cells (CRTH2) (DP2) in neuronal survival. PGD2 is the most abundant prostaglandin in brain and regulates sleep, temperature and nociception. It signals through two distinct G protein‐coupled receptors, DP1 and DP2, that have opposing effects on cyclic AMP (cAMP) production. Physiological concentrations of PGD2 potently and unexpectedly rescued neurons in paradigms of glutamate toxicity in cultured hippocampal neurons and organotypic slices. This effect was mimicked by the DP1‐selective agonist BW245C but not by the PGD2 metabolite 15d‐PGJ2, suggesting that neuroprotection was mediated by the DP1 receptor. Conversely, activation of the DP2 receptor promoted neuronal loss. The protein kinase A inhibitors H89 and KT5720 reversed the protective effect of PGD2, indicating that PGD2‐mediated neuroprotection was dependent on cAMP signaling. These studies indicate that activation of the PGD2 DP1 receptor protects against excitotoxic injury in a cAMP‐dependent manner, consistent with recent studies of PGE2 receptors that also suggest a neuroprotective effect of prostaglandin receptors. Taken together, these data support an emerging and paradoxical neuroprotective role of prostaglandins in the CNS.
Rotenone‐induced caspase 9/3‐independent and ‐dependent cell death in undifferentiated and differentiated human neural stem cells
Authors: Li Jiang , Spletter Maria L. , Johnson Delinda A. , Wright Lynda S. , Svendsen Clive N. , Johnson Jeffrey A.
Published: January 2005

We used human neural stem cells (hNSCs) and their differentiated cultures as a model system to evaluate the mechanism(s) involved in rotenone (RO)‐ and camptothecin (CA)‐induced cytotoxicity. Results from ultrastructural damage and terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling (TUNEL) staining indicated that RO‐induced cytotoxicity resembled CA‐induced apoptosis more than H2O2‐induced necrosis. However, unlike CA‐induced, caspase 9/3‐dependent apoptosis, there was no increased activity in caspase 9, caspase 3 or poly (ADP‐ribose) polymerase (PARP) cleavage in RO‐induced cytotoxicity, in spite of time‐dependent release of cytochrome c and apoptosis‐inducing factor (AIF) following mitochondrial membrane depolarization and a significant increase in reactive oxygen species generation. Equal doses of RO and CA used in hNSCs induced caspase 9/3‐dependent apoptosis in differentiated cultures. Time‐dependent ATP depletion occurred earlier and to a greater extent in RO‐treated hNSCs than in CA‐treated hNSCs, or differentiated cultures treated with RO or CA. In conclusion, these results represent a unique ultrastructural and molecular characterization of RO‐ and CA‐induced cytotoxicity in hNSCs and their differentiated cultures. Intracellular ATP levels may play an important role in determining whether neural progenitors or their differentiated cells follow a caspase 9/3‐dependent or ‐independent pathway in response to acute insults from neuronal toxicants.
Increased expression of phospholipase D1 in the brains of scrapie‐infected mice
Authors: Jin Jae‐Kwang , Kim Nam‐Ho , Min Do Sik , Kim Jae‐Il , Choi Jin‐Kyu , Jeong Byung‐Hoon , Choi Seung‐Il , Choi Eun‐Kyoung , Carp Richard I. , Kim Yong‐Sun
Published: January 2005

Mitochondrial dysfunction and free radical‐induced oxidative damage are critical factors in the pathogenesis of neurodegenerative diseases. Recently, phospholipid breakdown by phospholipase D (PLD) has been recognized as an important signalling pathway in the nervous system. Here, we examined the expression of PLD and alteration of membrane phospholipid in scrapie brain. We have found that protein expression and enzyme activity of PLD1 were increased in scrapie brains compared with controls; in particular, there was an increase in the mitochondrial fraction. PLD1 in mitochondrial membranes from scrapie brains, but not from control brains, was tyrosine phosphorylated. Furthermore, the concentration of mitochondrial phospholipids such as phosphatidylcholine and phosphatidylethanolamine was increased and the content of phosphatidic acid, a product of PLD activity, was up‐regulated in the mitochondrial membrane fractions. Immunohistochemically, PLD1 immunoreactivity was significantly increased in activated astrocytes in both cerebral cortex and hippocampus of scrapie brains. Taken together, these results suggest that PLD activation might induce alterations in mitochondrial lipids and, in turn, mediate mitochondrial dysfunction in the brains of scrapie‐infected mice.
The basic helix‐loop‐helix transcription factor Nex‐1/Math‐2 promotes neuronal survival of PC12 cells by modulating the dynamic expression of anti‐apoptotic and cell cycle regulators
Authors: Uittenbogaard Martine , Chiaramello Anne
Published: January 2005

The basic helix‐loop‐helix transcription factor Nex1/Math‐2 belongs to the NeuroD subfamily, which plays a critical role during neuronal differentiation and maintenance of the differentiated state. Previously, we demonstrated that Nex1 is a key regulatory component of the nerve growth factor (NGF) pathway. Further supporting this hypothesis, this study shows that Nex1 has survival‐inducing properties similar to NGF, as Nex1‐overexpressing PC12 cells survive in the absence of trophic factors. We dissected the molecular mechanism by which Nex1 confers neuroprotection upon serum removal and found that constitutive expression of Nex1 maintained the expression of specific G1 phase cyclin‐dependent kinase inhibitors and concomitantly induced a dynamic expression profile of key anti‐apoptotic regulators. This study provides the first evidence of the underlying mechanism by which a member of the NeuroD‐subfamily promotes an active anti‐apoptotic program essential to the survival of neurons. Our results suggest that the survival program may be viewed as an integral component of the intrinsic programming of the differentiated state.