bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of handling and electrofishing on plasma glucose and whole blood lactate of Leuciscus cephalus
Authors: Bracewell P. , Cowx I. G. , Uglow R. F.
Published: January 2004

Chub Leuciscus cephalus exposed to simulated pulsed direct current electrofishing operations exhibited rapid elevations in plasma glucose and blood lactate levels. Plasma glucose levels were significantly higher 0·5 h after simulated electrofishing operations, and peaked 2 h after treatment. Glucose levels remained high for up to 4 h. No changes in plasma glucose were evident following handling. Simulated electrofishing operations and handling induced an immediate lactacidosis in chub. Initial responses to both treatments were similar except that blood lactate was significantly higher in fish exposed to simulated electrofishing operations than in handled fish 5 and 15 min after treatment. Blood lactate remained elevated in fish exposed to simulated electrofishing operations for 2 h, while blood lactate of handled fish returned to levels similar to those in the control fish within 0·5 h post‐treatment.
A method for externally attaching radio transmitters to minimize dermal irritation
Authors: Crook D. A.
Published: January 2004

A method for externally attaching transmitters to fishes is described that reduces contact between the transmitter and the fish, thus reducing the potential for dermal irritation.
Staging larval and early juvenile Japanese anchovy based on the degree of guanine deposition
Authors: Takahashi M. , Watanabe Y.
Published: January 2004

Japanese anchovy Engraulis japonicus larvae and early juveniles were assigned to one of three developmental stages based on the degree of guanine deposition. The development in terms of the guanine deposition was a function of body size and age and was more strongly associated with the former. The degree of guanine deposition is found to be valid as a criterion to distinguish Japanese anchovies at the end of the metamorphosing stage.
Nutritional condition of metamorphosing sole: spatial and temporal analyses
Authors: Amara R. , Galois R.
Published: January 2004

Sole Solea solea larvae were collected during five cruises in the Bay of Biscay in 1992 and 1993. The larval growth rate, triacylgycerol (TAG) and sterol (ST) content, and the width of the marginal otolith increments were determined on the same individual larva as indicators of nutritional condition. The TAG content increased during the ontogenetic larval development up to an elevated value corresponding to the end of metamorphosis. During metamorphosis, sole larvae continued to accumulate TAG and to increase in length. Seasonal and yearly variations of growth and nutritional condition of sole larvae at the onset of metamorphosis were more important than spatial variations. Analysis of larval growth showed that, during each cruise, the faster growing larvae were generally those with the highest TAG content (and TAG : ST ratio). In 1993, larvae began to metamorphose earlier and their growth (both larval growth and recent growth) were significantly higher than in 1992. Their relatively low nutritional condition, however, seemed to be the result of a low accumulation of TAG. Sole metamorphosis occurs without growth arrest and the majority of the larvae during this phase are judged to be in good nutritional condition (TAG : ST ratio > 1). In the Bay of Biscay, metamorphosis does not seem to be a critical period in the life cycle of the sole. It is suggested that larvae originating from different cohorts probably have the same chance of survival during or just after metamorphosis when they enter the benthic environment.
Marine feeding of anadromousSalmo truttaduring winter
Authors: Knutsen J. A. , Knutsen H. , Olsen E. M. , Jonsson B.
Published: January 2004

Juvenile and adult anadromous troutSalmo truttautilize the sea for feeding during the winter in the Skagerrak. This finding conflicts with the traditional view that anadromous trout overwinter in fresh water. Adults, just prior to spawning, were captured at sea in October to December, and spent fish were caught at sea from October to April, showing that the fish may leave the stream and move to sea just after spawning and spend the winter there. During mid‐winter (January to February), the feeding probability (chance of finding a fish with food in its stomach) increased markedly with increasing body length, with no similar effect during early and late winter (October to December and March to April). Among individuals with food in their stomach (72·5%), there was no evidence for variation in feeding intensity [stomach fullness = (mass of stomach content)(fish body mass)−1] among early, mid‐, and late winter.
Purification and further characterization of a glycoprotein from the skin mucus of Japanese eels
Authors: Sumi T. , Hama Y , Nakagawa H. , Maruyama D. , Asakawa M.
Published: January 2004

A glycoprotein (EGP) was purified from the skin mucus of Japanese eel Anguilla japonica. Apparent average molecular mass of the EGP was estimated to be 500 000. The EGP was found to contain 30·8% NeuAc, 26·4% GalNAc, 6·4% Gal, 0·4% NeuGc and 25·1% Thr‐rich protein. EGP was treated with alkaline borohydride for the release of carbohydrate chains (oligosaccharide alditols). Three carbohydrate chains were isolated from the released carbohydrate chains by Sephadex G‐25 (superfine) gel filtration and HPLC. Using 1H‐NMR spectroscopy, methylation analysis and glycosidase digestion, the structures of the three carbohydrate chains were determined to be NeuAcα2→6GalNAc‐ol, NeuAcα2→3GalNAc‐ol and NeuAcα2→6(GalNAcα1→3)GalNAc‐ol. An overall structure for the sialoglycoprotein from the skin mucus is proposed: the molecule is considered to consist of highly glycosylated 10 glycopeptide units (containing >40 carbohydrate chains) that are linked to the hydroxyl amino acids and spaced on average two amino acids apart.
Alterations in air‐sac and skeleton of triploid Heteropneustes fossilis
Authors: Tiwary B. K. , Ray A. K.
Published: January 2004

Triploid stinging catfish Heteropneustes fossilis, when produced by cold shock, showed abnormalities in their air‐sacs and skeletons.
Repetitive acceleration swimming performance of brown trout in fresh water and after acute seawater exposure
Authors: Pedersen L. F. , Malte H.
Published: January 2004

The effect of acute seawater exposure on repeated swimming performance of brown trout Salmo trutta was investigated by use of a constant acceleration test (CAT). In fresh water, swimming speed was attained regardless of previous exercise, whereas swimming speed in sea water was significantly reduced during consecutive exercise.
Effects of delayed first feeding on the nutritional condition and mortality of California halibut larvae
Authors: Gisbert E. , Conklin D. B. , Piedrahita R. H.
Published: January 2004

The effect of the timing of first feeding (3, 4, 5, 6, 7 and 8 days post‐hatch, dph) on laboratory‐reared California halibut Paralichthys californicus larvae was evaluated by means of morphologic, morphometric and histological criteria. Larvae began to feed exogenously at 3 dph (2·7 ± 0·01 mm standard length, LS) at 18° C. Eye pigmentation, rather than mouth opening was the most distinctive trait of California halibut larvae at first feeding. Larval growth was significantly affected by the time of first exogenous feeding. At notochord flexion (21 dph), the LS of larvae fed for the first time at 3 dph was significantly larger (5·1 ± 0·1 mm) than that of those fed at 4 and 5 dph (4·9 ± 0·1 mm), although the latter fish had a more uniform size distribution. The point of no return was reached at 7 dph. Survival of larvae initially fed at 3, 4 and 5 dph was similar (58·4–60%), while no larvae were able to survive when food was offered for the first time between 6 and 8 dph. Food deprivation resulted in a progressive deterioration of the larval digestive system and atrophy of skeletal muscle fibres. Significant changes in the anterior and posterior enterocyte height were detected after 2 days of food deprivation. Similarly, tail height: LS and trunk length: LS ratios were the most sensitive morphometric indices to detect the effect of fasting on larval condition. Present results show that a combination of morphometric and histological variables can be used to evaluate the nutritional condition of California halibut larvae.
Endocrine and metabolic responses to stress in a laboratory population of the tropical damselfish Acanthochromis polyacanthus
Authors: Begg K. , Pankhurst N. W.
Published: January 2004

The effects of confinement and exercise on the stress response of the spiny damselfish Acanthochromis polyacanthus were investigated in a laboratory stock of fish. Cultured spiny damselfish had basal plasma cortisol values (<16 ng ml−1) similar to those found in wild fish, and basal plasma glucose and lactate levels that were similar to those found in other teleosts. Plasma cortisol concentrations increased in response to stress with a latency period of 5–10 min. Removal of the stressor resulted in partial recovery of cortisol levels by 24 h. Plasma glucose levels increased in response to stress in all experiments with significant increases occurring within 15 min of the imposition of stress. Elevations in plasma glucose concentrations were not initially reflected in changes in liver or muscle glycogen content, with significant reductions in liver glycogen concentrations only occurring in response to extended periods of stress. In contrast to many temperate species, plasma lactate concentrations did not consistently increase in response to stress, suggesting that the stress response in spiny damselfish is not strongly characterized by anaerobiosis.
Dentition in the African catfishesAndersonia (Amphiliidae) andSiluranodon (Schilbeidae) previously considered toothless
Authors: Golubtsov A. S. , Moots K. A. , Dzerjinskii K. F.
Published: January 2004

Based on light and scanning electron microscopic examination of their morphology, the dentition on both the premaxilla and dentary ofAndersonia(Amphiliidae) andSiluranodon(Schilbeidae) catfishes is described from samples taken from tributaries of the White Nile in south‐western Ethiopia. These monotypic African genera were previously believed to lack teeth on the lower jaw inAndersoniaand on both jaws inSiluranodon.Siluranodonexhibits an ontogenetic reduction: teeth were less frequently found in larger individuals than in smaller ones. In contrast to the adults of all other schilbeids, whose oral teeth are arranged in multiserial (or at least, biserial) bands,Siluranodonhas uniserial teeth on both the premaxilla and the dentary. The adaptive, ontogenetic and phylogenetic aspects of jaw‐tooth reduction in catfishes are discussed.
Remodelling of the vertebral axis during metamorphic shrinkage in the pearlfish
Authors: Parmentier E. , Lecchini D. , Vandewalle P.
Published: January 2004

Body shortening was observed in the pearlfish Carapus homei during metamorphosis. The tenuis larva at first possessed a suite of osseous vertebral bodies of similar length. The reduction in both the number and size of vertebrae followed increasing decalcification, degeneration of organic tissue and shortening. This involved a complete degradation and disappearance of the caudal tip vertebrae, and there was a reduction in the size of most of the remaining vertebrae. The further development of the vertebrae began with ossification of the neural and haemal arches before that of the vertebral body. This second part of the development followed a gradient: a gradual decreases towards the caudal tip in the size of the vertebrae and their completeness.
Metazoan parasites of Sebastes capensis from two localities in northern Chile as tools for stock identification
Authors: Oliva M. E. , Gonzalez M. T.
Published: January 2004

Examination of 290 red rockfish Sebastes capensis from two fishing grounds in northern Chile (Coquimbo 71°30′ W; 30°0′ S and Antofagasta 70°40′ W; 23°30′ S) revealed 8770 metazoan parasites, belonging to 18 taxa: Udonella caligorum(Udonellidae); Interniloculus chilensis, Paramicrocotyle sp. and Neobenedenia melleni(Monogenea); larval Gnathia sp., Cirolana sp. and Rocinela sp. (Isopoda); Helicometrina nimia, Diphtherostomum sp., Lecithochirium sp. and Pseudopecoelus sp. (Digenea); Ascarophis sebastodis, Anisakis sp. and larval Hysterothylacium sp. (Nematoda); Caligus cheilodactylus, Lepeophtheirus chilensis and Trifur tortuosus(Copepoda); larval Corynosoma australe(Acanthocephala). Ten species were found only in Coquimbo and three were found only in Antofagasta, species common to both localities were Pseudopecoelus sp., C. australe, Anisakis sp. and A. sebastodis. Evidence, based on qualitative differences between the parasite faunas of the red rockfish, suggests the existence of two discrete stocks.
Phylogeography and intraspecific genetic variation of prochilodontid fishes endemic to rivers of northern South America
Authors: Turner T. F. , McPhee M. V. , Campbell P. , Winemiller K. O.
Published: January 2004

Phylogeography and intraspecific genetic variation were studied in prochilodontids endemic to the Orinoco, Essequibo and Amazon River basins of northern South America. Portions of two protein‐encoding mitochondrial (mt) DNA genes, ND4 and COI, were examined using single‐strand conformational polymorphisms (SSCPs) and nucleotide sequencing. Phylogeographic analysis indicated that the geographically widespread Prochilodus rubrotaeniatus is paraphyletic, with individuals from the Orinoco sharing most recent common ancestry with co‐occurring Prochilodus mariae. A second Prochilodus rubrotaeniatus clade was composed of haplotypes found in the Rio Cuyuní(Essequibo Basin) and tributaries of the Rio Negro (Amazon Basin). Intraspecific genetic analysis suggested that a complex set of processes have influenced patterns of genetic variation in prochilodontid lineages. Prochilodus rubrotaeniatus is monomorphic at both loci in the Rio Negro and probably recently colonized this basin from the Rio Essequibo. Only two of 55 P. mariae exhibited variant haplotypes, and both had resulted from non‐synonymous changes in the ND4 region. These observations were counter to neutral expectation and consistent with the action of natural selection on the mitochondrion. Overall, these analyses implicate vicariance, demography and selection for driving diversification of prochilodontids in northern South America.
Distribution and onshore migration behaviour of burbot larvae in Lake Constance, Germany
Authors: Miler O. , Fischer P.
Published: January 2004

Larval abundance of burbot Lota lota in the pelagic zone of Lake Constance, Germany, peaked during April and remained at a constant but lower level until mid‐June. From the end of May onwards a significant diel vertical migration pattern was observed: while burbot larvae were distributed above as well as below the thermocline in the daytime with the highest percentages of abundance at water depths of 30 and 50 m (below the thermocline) on 5 and 25 June, they were concentrated from 2 to 15 m (above the thermocline) during the night. This migration pattern coincided with a significant decline in the food items preferred by burbot at this life stage, cyclopoid copepods. This phase of diel vertical migration lasted for c. 4 weeks until the burbot larvae suddenly disappeared from the pelagic zone. This indicated a short phase, lasting only a few days, of larval settlement into profundal benthic habitats. This was supported by a significant, abrupt decrease in the absolute growth rates of the larvae at day 56 after hatching. The day–night pattern of vertical migration observed could be assumed to be a transition phase from a pelagic to a benthic lifestyle, as reported for juveniles of several other, marine gadoid species.
Composition, structure and distribution of the ichthyoplankton in a Mediterranean coastal lagoon
Authors: Pérez‐Ruzafa A. , Quispe‐Becerra J. I. , García‐Charton J. A. , Marcos C.
Published: January 2004

The species composition and assemblage structure of the ichthyoplankton from the Mar Menor Lagoon in south‐east Spain are given. The fish larvae were sorted from zooplankton samples collected at 20 stations with a plankton net (50 cm mouth diameter and 500 μm mesh) during 36 surveys between February and December 1997. A total of 39 575 fish larvae representing 14 families, 22 genera and 36 species were identified. Gobiidae was the most dominant family (77·0%) followed by Blenniidae (19·4%) and Atherinidae (1·3%). The most abundant species were Gobius niger and Gobius paganellus, which accounted for 42·7 and 19·3% of the total respectively. These species were followed in order of relative abundance by Pomatoschistus marmoratus(13·9%), Parablennius pilicornis(9·4%), Lipophrys pavo(7·7%), Atherina boyeri(1·3%) and Parablennius tentacularis(1·3%). The high species diversity (2·0–2·8 bits individual−1 for the annual diversity spectra at each sampling station) reflected a diverse assemblage of species. The main commercial species in the lagoon (Sparidae and Mugilidae) were poorly represented among the ichthyoplankton and they probably enter the lagoon on the bottom as recruits. Chlorophyll a concentration in the water column was the main factor explaining the seasonal variation in larval abundance. Spatial distribution of larvae was related to hydrographical circulation patterns in the lagoon and the movement of marine‐spawned larvae through the channels connecting the lagoon with the Mediterranean Sea.
Intra‐sexual preferences for familiar fish in male guppies
Authors: Croft D. P. , Arrowsmith B. J. , Webster M. , Krause J.
Published: January 2004

Male guppiesPoecilia reticulatawere observed to develop shoaling preferences for familiar males over a 12 day period, at which time they showed a clear preference for familiar over non‐familiar males.
Gender‐ and season‐dependent relationships between testosterone, oestradiol and immune functions in wild roach
Authors: Vainikka A. , Jokinen E. I. , Kortet R. , Taskinen J.
Published: January 2004

Plasma testosterone and 17β‐oestradiol concentrations, differential leukocyte counts and proportion of dead Rhipidocotyle campanula gill parasites (parasite resistance) were determined five times during a year in two populations of roach Rutilus rutilus and analysed for seasonal and gender differences. In addition to the above immune variables, plasma Immunoglobulin M (IgM) concentration, chemiluminescence and migration differential of head kidney phagocytes, size of the spleen, haematocrit and total leukocyte count were correlated with sex hormones for each population, sampling time and sex separately, using condition factor as a partial correlate. There were no clear gender differences in the determined immune variables. Both testosterone and oestradiol concentrations were lowest after the spawning in June. Oestradiol was higher in females than in males, but testosterone was present in equal concentrations in both sexes. Statistically significant correlations between sex hormones and immune variables were rare and mainly without any patterns with respect to population, sex or sampling date. The meta‐analysis on individual correlations, however, revealed a positive relationship of plasma testosterone concentration to chemiluminescence of head kidney phagocytes, plasma IgM concentration and the proportion of dead R. campanula to all R. campanula on the gills. In the meta‐analysis, the concentration of oestradiol was not found to correlate with any of the studied immune variables.
Characteristics of mature male parr in the northernmost Atlantic salmon populations
Authors: Heinimaa S. , Erkinaro J.
Published: January 2004

The incidence, relative abundance and biological characteristics of mature male parr of Atlantic salmon Salmo salar were studied in two subarctic (69–70 N°) river systems in the northernmost part of Scandinavia. The proportion of mature males was low (0–25%) among ≥1 year‐old parr, and clearly lower than reported earlier in more southern rivers. The ages of mature males ranged from 1+ to 6 + year, the most abundant age group was 3 + year. Both age structure and size of the mature male parr varied between rivers and years. Mature male parr in the main stem were younger and also smaller than the parr of the same age in the tributaries.
Feature
Authors: Wall Frances
Published: January 2004

Numerous world class mineral deposits make the Kola Peninsula a ‘Mecca’ for mineralogists, and key economic deposits make it one of Russia's most important industrial areas. For geologists there is the challenge of explaining how this situation has come about.
Water relations and hydraulic control of stomatal behaviour in bell pepper plant in partial soil drying
Authors: Yao C. , Moreshet S. , Aloni B.
Published: January 2004

Two experiments, a split‐root experiment and a root pressurizing experiment, were performed to test whether hydraulic signalling of soil drying plays a dominant role in controlling stomatal closure in herbaceous bell pepper plants. In the split‐root experiment, when both root parts were dried, synchronous decreases in stomatal conductance (gs), leaf water potential (LWP) and stem sap flow (SFstem) were observed. The value of gs was found to be closely related to soil water potential (SWP) in both compartments. Tight relationships were observed between gs and stem sap flow under all conditions of water stress, indicating a complete stomatal adjustment of transpiration. When the half‐root system has been dried to the extent that its water uptake dropped to almost zero, declines in gs of less than 20% were observed without obvious changes in LWP. The reduced plant hydraulic conductance resulting from decreased sap flow and unchanged LWP may be a hydraulic signal controlling stomatal closure; the results of root pressurizing supported this hypothesis. Both LWP and gs in water‐stressed plants recovered completely within 25 min of the application of root pressurizing, and decreased significantly within 40 min after pressure release, indicating the hydraulic control of stomatal closure. Our results are in contrast to those of other studies on other herbaceous species, which suggested that chemical messengers from the roots bring about stomatal closure when plants are in water stress.
Improved temperature response functions for models of Rubisco‐limited photosynthesis
Authors: Bernacchi C. J. , Singsaas E. L. , Pimentel C. , Portis Jr A. R. , Long S. P.
Published: January 2004

Predicting the environmental responses of leaf photosynthesis is central to many models of changes in the future global carbon cycle and terrestrial biosphere. The steady‐state biochemical model of C3 photosynthesis of Farquhar et al. (Planta 149, 78–90, 1980) provides a basis for these larger scale predictions; but a weakness in the application of the model as currently parameterized is the inability to accurately predict carbon assimilation at the range of temperatures over which significant photosynthesis occurs in the natural environment. The temperature functions used in this model have been based on in vitro measurements made over a limited temperature range and require several assumptions of in vivo conditions. Since photosynthetic rates are often Rubisco‐limited (ribulose, 1‐5 bisphosphate carboxylase/oxygenase) under natural steady‐state conditions, inaccuracies in the functions predicting Rubisco kinetic properties at different temperatures may cause significant error. In this study, transgenic tobacco containing only 10% normal levels of Rubisco were used to measure Rubisco‐limited photosynthesis over a large range of CO2 concentrations. From the responses of the rate of CO2 assimilation at a wide range of temperatures, and CO2 and O2 concentrations, the temperature functions of Rubisco kinetic properties were estimated in vivo. These differed substantially from previously published functions. These new functions were then used to predict photosynthesis in lemon and found to faithfully mimic the observed pattern of temperature response. There was also a close correspondence with published C3 photosynthesis temperature responses. The results represent an improved ability to model leaf photosynthesis over a wide range of temperatures (10–40 °C) necessary for predicting carbon uptake by terrestrial C3 systems.
Responses of photosystem I compared with photosystem II to high‐light stress in tropical shade and sun leaves
Authors: Barth C. , Krause G. H. , Winter K.
Published: January 2004

Sun and shade leaves of several plant species from a neotropical forest were exposed to excessive light to evaluate the responses of photosystem I in comparison to those of photosystem II. Potential photosystem I activity was determined by means of the maximum P700 absorbance change around 810 nm (ΔA810max) in saturating far‐red light. Leaf absorbance changes in dependence of increasing far‐red light fluence rates were used to calculate a ‘saturation constant’, Ks, representing the far‐red irradiance at which half of the maximal absorbance change (ΔA810max/2) was reached in the steady state. Photosystem II efficiency was assessed by measuring the ratio of variable to maximum chlorophyll fluorescence, Fv/Fm, in dark‐adapted leaf samples. Strong illumination caused a high degree of photo‐inhibition of photosystem II in all leaves, particularly in shade leaves. Exposure to 1800–2000 μmol photons m−2 s−1 for 75 min did not substantially affect the potential activity of photosystem I in all species tested, but caused a more than 40‐fold increase of Ks in shade leaves, and a three‐fold increase of Ks in sun leaves. The increase in Ks was reversible during recovery under low light, and the recovery process was much faster in sun than in shade leaves. The novel effect of high‐light stress on the light saturation of P700 oxidation described here may represent a complex reversible mechanism within photosystem I that regulates light‐energy dissipation and thus protects photosystem I from photo‐oxidative damage. Moreover, we show that under high‐light stress a high proportion of P700 accumulates in the oxidized state, P700+. Presumably, conversion of excitation energy to heat by this cation radical may efficiently contribute to photoprotection.
What is child protection? Historical and methodological issues in comparative research on lastensuojelu/child protection
Authors: Hearn Jeff , Pösö Tarja , Smith Carole , White Sue , Korpinen Johanna
Published: January 2004

This article addresses comparative research on what has come to be called, in (British) English, ‘child protection’ or, rather differently, in Finnish ‘lastensuojelu’. In developing a cross‐national research project on lastensuojelu/child protection practices in England and Finland, we found it necessary to go back a few steps, to address what might usually be considered as ‘background issues’. This article discusses the welfare state traditions in both countries, especially with respect to families and children, in order to contextualise the focus of ongoing qualitative research on micro comparisons. When comparing the mundane practices of child protection and the ways problems and clienthoods are constructed, as in this study, historical, social, cultural and linguistic issues matter. Indeed, very basic concepts such as ‘child protection’ and ‘child protection case’ become problematic in the comparison.
Ideas, private institutions and American welfare state ‘exceptionalism’: the case of health and old‐age insurance, 1915–1965
Authors: Béland Daniel , Hacker Jacob S
Published: January 2004

Traditional theories of welfare state development divide into two camps: societal accounts and institutional accounts. The aim of the present article is to amend and enrich the institutional approach to US social policy by reconsidering key aspects of the genesis of the American welfare state: 1) showing that concepts such as ‘policy feedback’ and ‘path dependence’ need to be extended to encompass the effect of private social policies; and 2) taking policy paradigms and agenda setting more seriously than is the norm in institutional scholarship. The empirical analysis is divided into two parts. The first part explores the activities of the American Association for Labor Legislation (AALL) in the decade beginning in 1910 and the genesis of Social Security in the 1930s, while the second part examines the effect of the private benefit developments on policy choices between 1935 and 1965.
HIV‐infected African families living in Stockholm/Sweden: their social network, level of disclosure and knowledge about HIV
Authors: Åsander Ann‐Sofie , Belfrage Erik , Pehrson Pehr‐Olov , Lindstein Thomas , Björkman Anders
Published: January 2004

Most HIV‐infected parents in Stockholm are of African origin. Many of them have several children, but their social network is often limited. This article looks at the networks of these families in relation to different aspects of HIV in order to improve the support strategies. The theoretical basis of the study rests on network and ecological systems theory. The social networks of the families in the study were found to be generally of similar size in Sweden and in the home country. However, of 47 HIV‐infected parents only 21 (45%) had disclosed their HIV status to friends and relatives in Sweden. The lack of a social network was especially prominent among single women. Contact with counsellors at the HIV clinic and the social welfare office increased the probability of disclosure about HIV infection. The lack of knowledge about HIV transmission and about whom to inform about the infection stresses the importance of improved counselling. The support strategies aimed at broadening the patient's network and breaking their isolation need to be continued and strengthened.
Developments in home help for elderly people in Denmark: the changing concept of home and institution
Authors: Lewinter Myra
Published: January 2004

The official figures on provision of home help in Denmark are compromised in that they include figures for help delivered to people living in assisted‐living dwellings, facilities that were formerly considered nursing homes. Furthermore, many municipalities have integrated home help and nursing‐home care and report this as home help. This article examines the effect of these administrative arrangements on the provision of home help and the distribution of home help in terms of hours per week. There has been a polarisation in size of care packages: a smaller group of recipients composed largely of people residing in assisted‐living dwellings receive larger care packages, whereas the care packages to people living in their own dwellings have decreased in size. However, a sleight of hand of definitions regarding the concept of home has made the official figures on provision of home help look even more generous than they are.
Deprotonation of hydrochloride salts of amino acid esters and peptide esters using commercial zinc dust
Authors: Ananda K. , Suresh Babu V.V.
Published: January 2004

Abstract:The deprotonation of hydrochloride salts of ethyl and methyl esters of amino acids and peptides is accomplished using activated zinc dust. The reaction is neat and quantitative. Thus, the free amino acid esters and peptide esters have been isolated in good yield and purity.
The Interaction between a Most‐Favored‐Customer Clause and Price Dispersion: An Empirical Examination of the Medicaid Rebate Rules of 1990
Authors: Scott Morton Fiona M.
Published: January 2004

This paper examines the effect of the MFC rules adopted by Medicaid on both price dispersion and price levels in the wholesale pharmaceutical market. Theory suggests that the regulations should reduce price dispersion and increase the average price for those products with a high initial level of price dispersion. Using data which can only measure some dimensions of price discrimination, I find that discrimination falls for products sold to hospitals, but not drugstores. Branded drugs facing generic competition have the most dispersion ex ante. Prices of these brands rise with dispersion at the implementation of the new rules. The last two results are consistent with Scott Morton (1997), where I look only at price changes due to the law. The results of this paper confirm that part of the mechanism of action for the price increase is the high level of price dispersion for some products combined with the MFC.
Multiprincipal Agency Relationships as Implied by Product Market Competition
Authors: Gal‐Or Esther
Published: January 2004

This paper surveys recent work in contract theory that relates to the allocation of tasks among agents within an organization as well as to the effect of product market competition upon optimal contracting and agency costs.
Integrated Strategy and International Trade Disputes: The Kodak‐Fujifilm Case
Authors: Baron David P.
Published: January 2004

This paper examines the integration of market and nonmarket strategies in a setting involving market competition and international trade policy where governments serve as bargaining agents for firms. In the case modeled, the Eastman Kodak Company (Kodak) filed a Section 301 petition under US trade law against practices of Fuji Photo Film Company (Fujifilm) in the Japanese distribution system that Kodak alleges constitute trade barriers. The model has four components. The market model characterizes the competition between Fujifilm and Kodak, incorporating characteristics descriptive of the demand and market structure in Japan. Enforcement of an international trade agreement focusing on practices in a distribution system are problematic, so the second model characterizes the sustainability of concessions obtained through a trade agreement using a repeated game extension of the market model. The third model characterizes the bargaining between the US and Japanese governments using the preferences induced by the market model and the limits on sustainable concessions characterized in the second model. Using a common‐agency framework, the fourth model represents the nonmarket competition between the two firms as they work to influence the bargaining positions of the governments. The result is a model in which market and nonmarket strategies are integrated in a formal theory of the resolution of trade disputes and the subsequent effects on market competition. The equilibrium characterized allows a comparative statics analysis of the synergies between market and nonmarket strategies.
The FCC Spectrum Auctions: An Early Assessment
Authors: Cramton Peter
Published: January 2004

This paper analyzes six spectrum auctions conducted by the Federal Communications Commission from July 1994 to May 1996. These auctions were simultaneous multiple‐round auctions in which collections of licenses were auctioned simultaneously. This auction form proved remarkably successful. Similar items sold for similar prices, and bidders successfully formed efficient aggregations of licenses. Bidding behavior differed substantially in the auctions. The extent of bidder competition and price uncertainty played an important role in determining behavior. Bidding credits and installment payments also played a major role in several of the auctions.
Laboratory Experimental Testbeds: Application to the PCS Auction
Authors: Plott Charles R.
Published: January 2004

The paper reviews the uses of laboratory experimental economics methods in the background research and implementation of the Personal Communication Systems auctions held by the Federal Communications Commission. The applications began during the rule making process with the testing of broad rules that might be implemented. Data from experiments were systematically used. The methods were used again in the software development process where several important contributions were made. Finally, experiences gained from the study of experimental auction processes were used in the actual management of the first auctions and in interpreting auction performance.
Experiments Testing Multiobject Allocation Mechanisms
Authors: Ledyard John O. , Porter David , Rangel Antonio
Published: January 2004

This paper reports the results of over 130 auctions conducted under controlled conditions to examine the robustness of several auction mechanisms to allocate multiple objects. The simultaneous discrete auction process used by the Federal Communications Commission to allocate Personal Communications licenses was contrasted with a sequential auction and a combinatorial auction over a variety of demand conditions. In test environments created to check only the minimum competency of the procedures, the simultaneous discrete auction process produces highly efficient allocations, approaching levels similar to those found with a continuous form of the auction, and it outperforms a sequential auction. However, in environments created to stress test the procedures, a combinatorial auction outperforms the simultaneous discrete auction.
Oligopoly, Financial Structure, and Resolution of Uncertainty
Authors: Hughes John S. , Kao Jennifer L. , Mukherji Arijit
Published: January 2004

We characterize equilibria of a multistage game in which competing duopolists may acquire and share information in advance of choosing their financial structure which, in turn, precedes production. Given sufficient uncertainty, equilibria exist in which the efficiency and, possibly, coordination gains to acquiring and sharing perfect information are sufficient to break Brander and Lewis's (1986) result wherein both firms issue debt to their mutual disadvantage. However, more interesting may be the robustness of that result when uncertainty is low or when information is imperfect. The key insight is that the consequences of issuing debt are invariant to the level of uncertainty, given that firms can recalibrate the terms of debt to achieve the Stackelberg solution.
Yardstick Competition and Investment Incentives
Authors: Dalen Dag Morten
Published: January 2004

This paper analyzes how firms' investment incentives are affected by yardstick competition in a situation in which the regulator is unable to commit himself to the regulatory contract before firms invest. Despite its rent‐extracting property, yardstick competition does not necessarily reduce efficiency‐improving investment. Considering firm‐specific investment, yardstick competition is shown to increase investment incentives over individual regulation affirms. In this case, therefore, yardstick competition both reduces the regulator's informational problem ex post and strengthens the firms' investment incentives ex ante. If instead investment is industry‐specific, incentives to invest are lowered by yardstick competition.
Health‐Care Payment Systems: Cost and Quality Incentives—Comment
Authors: Sharma Rajiv L.
Published: January 2004

This note analyzes the incentives for cost reduction that different payment policies provide to profit‐maximizing health‐care providers. Ching‐to Albert Ma (1994) proposes a reimbursement mechanism that seeks to induce first‐best cost reduction by using a combination of cost reimbursement and prospective payment in a model where higher effort on the part of the health‐care provider reduces treatment costs. This note shows that a mechanism of this type, generally, will not result in first‐best cost reduction. However, such a mechanism is optimal when the payer has efficiency and distributional concerns.
The Effectiveness and Targeting of Television Advertising
Authors: Shachar Ron , Anand Bharat N.
Published: January 2004

Television networks spend about 16% of their revenues on tune‐ins, which are previews or advertisements for their own shows. In this paper, we examine two questions. First, what is the informational content in advertising? Second, is this level of expenditures consistent with profit maximization? To answer these questions, we use a new and unique micro‐level panel dataset on the television viewing decisions of a large sample of individuals, matched with data on show tune‐in advertisements. The difference in effectiveness of advertisements between “regular” shows (about which viewers are assumed to have substantial information a priori) and “specials” (about which they have very little) reveals the value of information in advertisements and the different roles that information can play. The number of exposures for each individual is likely to be correlated with their preferences, since networks target their audiences. We address this endogeneity problem by controlling for observed, and integrating the unobserved, characteristics of individuals, and find that the estimated effects of tune‐ins are still large. Finally, we find that actual expenditures on tune‐ins closely match the predicted optimal levels of spending.
Strategic Invasion in Markets with Switching Costs
Authors: Wang Ruqu , Wen Quan
Published: January 2004

We investigate the role of consumer switching costs in a three‐stage model in which the entrant and the incumbent firm set prices sequentially and then the consumers decide from which firm to buy. We characterize the unique subgame perfect equilibrium and find that even an entrant with a higher marginal cost may profitably invade part of the market due to the existence of switching costs. Switching costs benefit both firms but harm consumers. This model is used to understand pricing behavior in the US telecommunications industry.
Hiring Risky Workers: Some Evidence
Authors: Burgess Simon , Lane Julia , Stevens David
Published: January 2004

Lazear recently suggested that firms that do not expect to live for a long time will hire only safe workers. Hence their worker turnover will be lower. In this paper we test this hypothesis using both the industry growth rate and industry‐average age of establishments as measures of the horizon for a particular firm. We find mixed results, both at the industry level and at the establishment level. Establishments in growing industries do indeed exhibit higher churning flows, but a high average age of establishments reduces rather than increases churning.
A Strategic Approach to Software Protection*
Authors: Shy Oz , Thisse Jacques‐Françlois
Published: January 2004

This paper demonstrates that there is a strategic reason why software firms have followed consumers' desire to drop software protection. We analyze software protection policies in a price‐setting duopoly software industry selling differentiated software packages, where consumers' preference for particular software is affected by the number of other consumers who (legally or illegally) use the same software. Increasing network effects make software more attractive to consumers, thereby enabling firms to raise prices. However, it also generates a competitive effect resulting from feircer competition for market shares. We show that when network effects are strong, unprotecting is an equilibrium for a noncooperative industry.
Mergers and Exclusionary Practices in Health Care Markets
Authors: Gal‐Or Esther
Published: January 2004

We evaluate the relationship between insurers (payers) and providers of health care (hospitals) when they each have a nonnegligible share of the market. We focus in particular on their incentives to merge and the existence of equilibria where payers offer preferential treatment to a subset of hospitals. We demonstrate that hospitals are more likely to merge without consolidating their capacities the less competitive they are vis‐à‐vis the payer's market. Payers are more likely to merge without consolidating their capacities the less competitive either the hospitals' or the payers' market is. A given payer follows an exclusionary strategy when its starting bargaining position vis‐à‐vis hospitals is weak. At such exclusionary equilibria, payers tend to distinguish themselves from neighboring payers by contracting with a different subset of hospitals.
Separating the True Effect from Gaming in Incentive‐Based Contracts in Health Care
Authors: Lu Mingshan
Published: January 2004

This paper studies the effect of incentive regulation on health care. In the context of incentive‐based health contracts, which might also introduce an incentive for the providers simply to report better treatment outcomes, evaluation of treatment using the information supplied by the providers (reported output) could be problematic. The systematic error on the output report is called providers' gaming behavior. This paper develops a general method for decomposing the effect of incentive‐based contracts on performance into the true effect, which is the result of clinicians' improved effort induced by the contract, and the gaming effect, which is due to the change in the providers' reporting practice. The method follows the essence of linear structural relation (LISREL) models, and the true treatment output is modeled using a latent variable. Various output measures can be included in the structural evaluation model, but objective measure(s) (output measures not affected by providers' potential gaming) must be constructed based on available information to identify gaming through its correlation with the reported measures. The strengths of this method are that information from more than one output measure can be used, no monitoring system is required, and the construction of a gold‐standard measure is not necessary. This method is applied to evaluate the impact of Maine's performance‐based contracting on its public providers' substance‐abuse services. Evidence of gaming is found in Maine's system, which remains robust in most of the sensitivity analyses. The methodology developed here can be used to evaluate the impact of a broad range of incentive‐based contracts.
Price and Nonprice Competition with Endogenous Market Structure
Authors: Symeonidis George
Published: January 2004

This paper examines the effect of the intensity of short‐run price competition and other exogenous variables that affect gross profit margins—such as the degree of product differentiation and the consumers' responsiveness to quality—on market structure and on advertising and R&D expenditure. A key result is that more intense short‐run competition can lead to lower concentration in industries with high advertising or R&D intensity, unlike exogenous‐sunk‐cost industries. Also, price competition has a negative effect on advertising or R&D expenditure. A case study is also presented, which is consistent with the theoretical results of the paper.
Exercising Market Power in Proprietary Aftermarkets
Authors: Borenstein Severin , Mackie‐Mason Jeffrey K. , Netz Janet S.
Published: January 2004

Over 20 recent antitrust cases have turned on whether competition in complex durable‐equipment markets prevents manufacturers from exercising market power over proprietary aftermarket products and services. We show that the price in the aftermarket will exceed marginal cost despite competition in the equipment market. Absent perfectly contingent long‐term contracts, firms will balance the advantages of marginal‐cost pricing to future generations of consumers against the payoff from monopoly pricing for current, locked‐in equipment owners. The result holds for undifferentiated Bertrand competition, differentiated duopoly, and monopoly equipment markets. We also examine the effects of market growth and equipment durability.
Pay to Switch or Pay to Stay: Preference‐Based Price Discrimination in Markets with Switching Costs
Authors: Shaffer Greg , Zhang Z. John
Published: January 2004

In many markets, firms can price discriminate between their own customers and their rivals' customers, charging one price to consumers who prefer their own product and another price to consumers who prefer a rival's product. We find that when demand is symmetric, charging a lower price to a rival's customers is always optimal. When demand is asymmetric, however, it may be more profitable to charge a lower price to one's own customers. Surprisingly, price discrimination can lead to lower prices to all consumers, not only to the group that is more elastic, but also to the less elastic group.