bluuebunny/crossref_metadata_2025 huggingface dataset:
Competition, Payers, and Hospital Quality1
Authors: Gowrisankaran Gautam , Town Robert J.
Published: December 2003

Objective. To estimate the effects of competition for both Medicare and HMO patients on the quality decisions of hospitals in Southern California.

Data Source. Secondary discharge data from the Office of Statewide Health Planning and Development for the State of California for the period 1989–1993.

Study Design. Outcome variables are the risk‐adjusted hospital mortality rates for pneumonia (estimated by the authors) and acute myocardial infarction (AMI) (reported by the state of California). Measures of competition are constructed for each hospital and payer type. The competition measures are formulated to mitigate the possibility of endogeneity bias. The relationships between risk‐adjusted mortality and the different competition measures are estimated using ordinary least squares.

Principal Findings. The study finds that an increase in the degree of competition for health maintenance organization (HMO) patients is associated with a decrease in risk‐adjusted hospital mortality rates. Conversely, an increase in competition for Medicare enrollees is associated with an increase in risk‐adjusted mortality rates for hospitals.

Conclusions. In conjunction with previous research, the estimates indicate that increasing competition for HMO patients appears to reduce prices and save lives and hence appears to improve welfare. However, increases in competition for Medicare appear to reduce quality and may reduce welfare. Increasing competition has little net effect on hospital quality in our sample.
Does Aggressive Care Following Acute Myocardial Infarction Reduce Mortality? Analysis with Instrumental Variables to Compare Effectiveness in Canadian and United States Patient Populations
Authors: Beck Christine A. , Penrod John , Gyorkos Theresa W. , Shapiro Stan , Pilote Louise
Published: December 2003

Background. Previous U.S. studies suggest that the incremental (“marginal”) use of the aggressive approach to care for acute myocardial infarction (AMI) in patients differing only in their distance to hospitals offering aggressive care may be associated with small mortality benefits. We hypothesized that the marginal benefits should be larger in Canada, as the country is operating on a lower margin because the approach to care is more conservative overall.

Methods. This retrospective study used administrative data of hospital admissions and health services for all patients admitted for a first AMI in Quebec in 1988 (n=8,674). We used differential distances to hospitals offering aggressive care as instrumental variables when measuring mortality up to four years after AMI.

Results. Of the 4,422 subjects who were ≥ 65 years old, 11 percent received cardiac catheterization within 90 days after admission. In a previous study that applied similar methodology to the 1987 U.S. Medicare population, 23 percent of subjects received catheterization within 90 days. As in the U.S. study, we found that subjects living closer to hospitals offering aggressive care were more likely to receive aggressive care than subjects living further away (26 percent versus 19 percent received cardiac catheterization within 90 days; 95 percent CI: 5 percent to 9 percent). Unlike the U.S. study, we found no differences in mortality across the “close” versus “far” differential distance groups (unadjusted differences at one year: 1 percent; 95 percent CI: −1 percent to 3 percent). This absence of association held in elderly (≥ 65 years) and younger age groups. Adjusted results also showed no differences between subjects receiving aggressive versus conservative care (at one year: 4 percent; 95 percent CI: −11 percent to 20 percent).

Conclusions. Contrary to our hypothesis, but consistent with results from numerous randomized trials and observational studies, we cannot confirm that, on the margin, the aggressive approach to post‐AMI care is associated with mortality benefits in Canada.
Mental Health Services Use among School‐Aged Children with Disabilities: The Role of Sociodemographics, Functional Limitations, Family Burdens, and Care Coordination
Authors: Witt Whitney P. , Kasper Judith D. , Riley Anne W.
Published: December 2003

Objective. To examine the use of mental health services and correlates of receiving services among community‐dwelling children with disabilities, ages 6 to 17 years.

Study Design. Data are from the 1994 and 1995 National Health Interview Survey Disability Supplements (NHIS‐D), conducted by the National Center for Health Statistics. The study sample is 4,939 children with disabilities, representing an estimated eight million children with disabilities nationwide. Parents of children under 16 years of age reported (17‐year‐olds self‐reported) on health, emotional and behavioral problems, mental health services use, and who, if anyone, coordinated the child's health care.

Principal Findings. Among disabled children with poor psychosocial adjustment (11.5 percent), only 41.8 percent received mental health services in the past year. Multivariate logistic regression analysis showed service use was associated with poor psychosocial adjustment; communication, social, and learning‐related functional impairments; public health insurance; and financial family burdens. Younger and black disabled children were less likely to receive mental health services. The odds of service use were greater with the involvement of a health professional in coordinating care, in contrast to no one or family only. Moreover, children with disabilities were more likely to use outpatient mental health services if their care was jointly coordinated by a family member and a health professional, compared to a health professional working alone. In contrast to inpatient and outpatient care, race and family burden were not associated with the likelihood of mental health counseling in special education school settings.

Conclusions. Findings indicate that only two in five disabled children with poor psychosocial adjustment receive mental health services. Differences by age, race, and insurance coverage suggest that inequalities to access exist. However, the school setting may be one in which some barriers to mental health services for disabled children are reduced. The study also shows that the involvement of health professionals in care coordination is associated with greater access to mental health care for disabled children. These findings underscore the importance of engaging both health care professionals and the family in the care process.
Psychometric Properties of the Consumer Assessment of Health Plans Study (CAHPS®) 2.0 Adult Core Survey
Authors: Lee Hargraves J. , Hays Ron D. , Cleary Paul D.
Published: December 2003

Objective. To estimate the reliability and validity of survey measures used to evaluate health plans and providers from the consumer's perspective.

Data Sources. Members (166,074) of 306 U.S. health plans obtained from the National CAHPS® Benchmarking Database 2.0, a voluntary effort in which sponsors of CAHPS® surveys contribute data to a common repository.

Study Design. Members of privately insured health plans serving public and private employers across the United States were surveyed by mail and telephone. Interitem correlations and correlations of items with the composite scores were estimated. Plan‐level and internal consistency reliability are estimated. Multivariate associations of composite measures with global ratings are also examined to assess construct validity. Confirmatory factor analysis is used to examine the factor structure of the measure.

Findings. Plan‐level reliability of all CAHPS® 2.0 reporting composites is high with the given sample sizes. Fewer than 170 responses per plan would achieve plan‐level reliability of .70 for the five composites. Two of the composites display high internal consistency (Cronbach's alpha >=.75), while responses to items in the other three composites were not as internally consistent (Cronbach's alpha from .58 to .62). A five‐factor model representing the CAHPS® 2.0 composites fits the data better than alternative two‐ and three‐factor models.

Conclusion. Two of the five CAHPS® 2.0 reporting composites have high internal consistency and plan‐level reliability. The other three summary measures were reliable at the plan level and approach acceptable levels of internal consistency. Some of the items that form the CAHPS® 2.0 adult core survey, such as the measure of waiting times in the doctor's office, could be improved. The five‐dimension model of consumer assessments best fits the data among the privately insured; therefore, consumer reports using CAHPS® surveys should provide feedback using five composites.
Sampling Patients within Physician Practices and Health Plans: Multistage Cluster Samples in Health Services Research
Authors: Adams John L. , Wickstrom Steven L. , Burgess Margaret J. , Lee Paul P. , Escarce José J.
Published: December 2003

Objective. To better inform study design decisions when sampling patients within health plans and physician practices with multiple analysis goals.

Study Setting. Chronic eye care patients within six health plans across the United States.

Study Design. We developed a simulation‐based approach for designing multistage samples. We created a range of candidate designs, evaluated them with respect to multiple sampling goals, investigated their tradeoffs, and identified the design that is the best compromise among all goals. This approach recognizes that most data collection efforts have multiple competing goals.

Data Collection. We constructed a sample frame from all diabetic patients in six health plans with evidence of chronic eye disease (glaucoma and retinopathy).

Principal Findings. Simulations of different study designs can uncover efficiency gains as well as inform potential tradeoffs among study goals. Simulations enable us to quantify these efficiency gains and to draw tradeoff curves.

Conclusions. When designing a complex multistage sample it is desirable to explore the tradeoffs between competing sampling goals via simulation. Simulations enable us to investigate a larger number of candidate designs and are therefore likely to identify more efficient designs.
The Association between Multiple Domains of Discrimination and Self‐assessed Health: A Multilevel Analysis of Latinos and Blacks in Four Low‐Income New York City Neighborhoods
Authors: Stuber Jennifer , Galea Sandro , Ahern Jennifer , Blaney Shannon , Fuller Crystal
Published: December 2003

Objective.This study examines the association between discrimination due to race and other attributes (e.g., sex, age) and self‐assessed mental and physical health among Latinos and blacks.

Data Source.Latino and black adult participants (n=873) identified by random digit dialing were interviewed by telephone in four low‐income neighborhoods in New York City: the South Bronx, East Harlem, Central Harlem, and Bedford‐Stuyvesant.

Study Design.In this cross‐sectional study, generalized estimating equations were used to fit multilevel multivariable models to test the association between discrimination and poor mental and physical health while controlling for socioeconomic status, access to health care, social support, smoking, and the racial and ethnic composition of each neighborhood.

Principal Findings.Discrimination due to race and discrimination due to other attributes were associated with poor self‐assessed mental but not physical health in separate multivariable models. Persons who experienced multiple domains of discrimination had a greater probability of reporting poor mental health than persons who experienced no discrimination.

Conclusions.Discrimination due to race and other attributes was a significant correlate of mental health among Latinos and blacks independent of other accepted determinants of health.
On the Importance of Age‐Adjustment Methods in Ecological Studies of Social Determinants of Mortality
Authors: Milyo Jeffrey , Mellor Jennifer M.
Published: December 2003

Objective.To illustrate the potential sensitivity of ecological associations between mortality and certain socioeconomic factors to different methods of age‐adjustment.

Data Sources.Secondary analysis employing state‐level data from several publicly available sources. Crude and age‐adjusted mortality rates for 1990 are obtained from the U.S. Centers for Disease Control. The Gini coefficient for family income and percent of persons below the federal poverty line are from the U.S. Bureau of Labor Statistics. Putnam's (2000) Social Capital Index was downloaded fromhttp://www.bowlingalone.com; the Social Mistrust Index was calculated from responses to the General Social Survey, following the method described inKawachi et al. (1997). All other covariates are obtained from the U.S. Census Bureau.

Study Design.We use least squares regression to estimate the effect of several state‐level socioeconomic factors on mortality rates. We examine whether these statistical associations are sensitive to the use of alternative methods of accounting for the different age composition of state populations. Following several previous studies, we present results for the case when only mortality rates are age‐adjusted. We contrast these results with those obtained from regressions of crude mortality on age variables.

Principal Findings.Different age‐adjustment methods can cause a change in the sign or statistical significance of the association between mortality and various socioeconomic factors. When age variables are included as regressors, we find no significant association between mortality and either income inequality, minority racial concentration, or social capital.

Conclusions.Ecological associations between certain socioeconomic factors and mortality may be extremely sensitive to different age‐adjustment methods.
Priming Reduced Extracorporeal Circulation Setup (PRECiSe) with the DeltaStream Diagonal Pump
Authors: Beholz Sven , Kessler Michael , Thölke Ralf , Konertz Wolfgang F.
Published: December 2003

Abstract:  Different systems for beating heart procedures and low priming systems limited to coronary artery bypass grafting (CABG) have been introduced. We describe Priming Reduced Extracorporeal Circulation Setup (PRECiSe), a new low priming system which sup‐plies all the features of cardiopulmonary bypass (CPB). PRECiSe incorporates the DeltaStream diagonal pump, which pumps blood from the right atrium to the aorta via a membrane oxygenator and a filter; the system is placed beneath the patient's head resulting in extremely short tubing. A reservoir allows the use of suckers and vents. Autologous blood priming furthers reduces hemodilution. In a safety study the system was used for extracorporeal circulation in 11 patients undergoing CABG without adverse  effects. By use of PRECiSe mean priming was reduced to 268.5 ml resulting in minimal hemo‐dilution and transfusion requirements.
Effect of Hemodiafiltration on Pulmonary Hemodynamics in Endotoxic Shock
Authors: Lambermont B. , Kolh P. , Ghuysen A. , Moonen M. , Morimont P. , Gérard P. , Tchana‐Sato V. , Rorive G. , D’Orio V.
Published: December 2003

Abstract:  Hemofiltration can improve pulmonary hemodynamics during septic shock. The main objective of the study was to determine whether hemodiafiltration (HDF) would also have beneficial effects on pulmonary hemodynamics during septic shock. In the Endo group, six anesthetized pigs received a 0.5 mg/kg endotoxin infusion over 30 min. In the HDF group (n = 6), HDF was started 30 min after the end of the endotoxin infusion, while in the Control group (n = 4) they received HDF but no endotoxin infusion. Pulmonary hemodynamics were analyzed in detail with a four‐element windkessel model. Although in the Control group, HDF did not alter pulmonary hemodynamic parameters, in the HDF group, it was responsible for an amplification of the deleterious pulmonary vascular response to endotoxin insult. Our results show that HDF must be used cautiously in septic shock since it can precipitate right heart failure by increasing pulmonary vascular resistance.
Individual and population‐level food consumption by cyprinids and percids in a mesotrophic lake
Authors: Tolonen K. T. , Karjalainen J. , Staff S. , Leppä M.
Published: December 2003

Abstract – Mesotrophic Lake Pohjalampi in eastern Finland was fished intensively from 1992 to 1996. In 1996, the biomasses of the dominant fish species, roach and bream, were reduced to 14% and 6%, respectively, of that in 1992. The total biomass of percids was, however, unchanged or slightly increased. The proportion of benthic invertebrates in the total food of the fish decreased from 57% to 36% during the study period, whereas the proportion of zooplankton increased from 31% to 56%. At the same time the number of young planktivorous fish increased. Thus, the main object of fish predation turned from benthic invertebrates to zooplankton due to change in fish population structure. At the beginning of the study the amount of detritus eaten by cyprinids was about 620 kg · ha−1 · year−1, but this decreased by 82% due to the intensive fishing. Thus, by recycling nutrients from the sediment, the detrivorous‐benthivorous feeding of cyprinids is an important factor in the nutrient balance of the lake.Note
Stream habitat use and diet of juvenile (0+) brown trout and grayling in sympatry
Authors: Degerman E. , Näslund I. , Sers B.
Published: December 2003

Abstract – Electrofishing survey data and experiments carried out in a semi‐natural stream were used to test the hypothesis that interactions between underyearling (0+) trout and grayling during their first summer affect habitat use and diet. The survey data revealed a general difference in habitat use, with 0+ grayling being more common than 0+ trout in large streams and deeper sections. It was also found that in the presence of trout, finer substrate and shallower sections were utilised more by grayling. Field experiments were carried out with three treatments; trout alone, grayling alone and the two species together. In both the July and September experiments grayling tended to occupy deeper sections than trout. Trout abundance was higher in shallow areas in sympatry, while no such difference was found in allopatry. The rate of disappearance of grayling from the study sections was significantly higher in sympatry in July, while no difference was found in September. In July the size difference between species and the degree of dietary overlap were small and non‐significant, respectively, indicating that the two species were strongly competing.Note
Growth of 0+ perch (Perca fluviatilis) predating on 0+ bream (Abramis brama)
Authors: Borcherding J. , Maw S. K. , Tauber S.
Published: December 2003

Abstract – Larvae and juveniles of perch Perca fluviatilis and bream Abramis brama of Lake Speldrop, a highly eutrophicated gravel‐pit lake in the floodplain of the Lower Rhine, were used in laboratory experiments to study predation of perch on bream. In the first series of experiments (control), 0+ perch of 30 mm total length (TL) did not prey on 0+ roach of about 24 mm TL. The perch fed only on zooplankton, resulting in low growth rates of 0.17 mm · day−1. In the second series of experiments, perch (30 mm TL) were combined with 0+ bream with an average TL of 14 and 19 mm at different ratios. As in the first series, even a nine‐fold higher amount of zooplankton food had no significant influence on the growth rate of perch, regardless of the perch:bream ratio. At a perch: bream ratio of 7:1 and 4:4 all bream were eaten by the perch and restocked twice daily. At the end of the experiment, the TL of perch at a perch:bream ratio of 7:1 was significantly lower compared to a perch:bream ratio of 4:4 (mean growth rates at 7:1 of 0.16 mm · day−1 and at 4:4 of 0.35 mm · day−1). At the perch:bream ratio of 1:7, perch fed on bream in varying amounts, averaging between 3 and 12 bream per day and per individual. After 20 days, the final length of these fish was always significantly higher than the TL of perch at other perch:bream ratios and increased in correlation to number of bream eaten per day (mean growth rate 1.13 mm · day−1). The results are discussed with respect to the piscivore‐dominated fish community of the eutrophied Lake Speldrop.Note
Individual variation in early life‐history traits in brown trout
Authors: Vøllestad L. A. , Lillehammer T.
Published: December 2003

Abstract – We studied the variability of early life history traits in individually raised progeny of brown trout Salmo trutta L. Eggs from two dams were each fertilized with sperm from 10 sires, producing 20 full‐sib families. Each individual progeny was followed from fertilization until death without exogenous food. Egg size was positively correlated with a number of life‐history traits, especially length and yolk sac volume at hatching and length at death, and these traits were strongly influenced by maternal effects. We found significant additive genetic variance for growth rate, length at death and life span without external food. Thus these early life‐history traits may be modulated by natural selection. We found positive phenotypic and genetic correlations between most early life‐history traits. However, life span without external food was negatively correlated with growth rate, indicating a genetic trade‐off.Note
Immune responses following simian/human immunodeficiency virus (SHIV) challenge of rhesus macaques after human immunodeficiency virus (HIV)‐1 third variable domain (V3) loop‐based genetic immunization
Authors: Le Borgne Sylvie , Le Grand Roger , Michel Marie‐Louise , Vaslin Bruno , Boson Bertrand , Janvier Geneviève , Aubertin Anne‐Marie , Dormont Dominique , Rivière Yves
Published: December 2003

Following DNA immunization of rhesus macaques with a plasmid encoding the human immunodeficiency virus (HIV)‐1 third variable domain (V3) loop, presented by pseudo‐viral envelope particles of hepatitis B virus, specific immune responses were induced. The primates were then inoculated with a chimeric simian/human immunodeficiency virus (SHIV). All the animals were infected, but the V3‐specific immunization provided a relative attenuation of the acute phase of infection in the absence of neutralizing antibody. In all animals, SHIV‐specific cytotoxic T‐lymphocyte precursors (CTLp) were detected early in peripheral blood and lymph nodes. The viremia peak correlated significantly with the decrease in CD4+ T cells and with a transient increase in the percentage of natural killer cells. The infection induced an oligoclonalization of the CD8+ T‐cell variable β chain repertoire in the blood. Surprisingly, HIV envelope‐specific CTLp generated by genetic immunization may be governed by distinct circulation rules compared to SHIV‐specific CTLp induced by infection.
Multiplicities and some enzymatic characteristics of ape pepsinogens and pepsins
Authors: Narita Yuichi , Oda Sen‐ichi , Takenaka Osamu , Kageyama Takashi
Published: December 2003

Pepsinogen levels in ape stomachs were comparable to those in macaques and significantly higher than those in the stomachs of other mammals, including carnivores and ruminants. The occurrence of multiple forms of pepsinogens was remarkable. Nine, sixteen, eight, and fourteen pepsinogens were purified or partially purified from the gastric mucosa of a gibbon, orang‐utan, gorilla, and chimpanzee, respectively. Most of these were type‐A pepsinogens, and only one type‐C pepsinogen was identified in each ape. The two types could be readily distinguished by staining for proteolytic activity on polyacrylamide gel electrophoresis (PAGE) in the presence/absence of pepstatin. Type‐A pepsinogens were further divided into two subtypes. One subtype, constituting a major group of pepsinogens in apes, exhibited high hemoglobin‐digestive activity. The other subtype was specified by a relatively high content of Lys and low hemoglobin‐digestive activity. It is likely that pepsinogen‐A genes have been duplicated several times as hominoids, including humans, evolved in the primate lineage. The presence of multiple pepsinogens in apes might be advantageous in the efficient digestion of a wide variety of foods.
Conjoined twins in a rhesus monkey (Macaca mulatta)
Authors: Canfield D. , Brignolo L. , Peterson P.E. , Hendrickx A.G.
Published: December 2003

Conjoined twinning is an extremely rare occurrence among human and nonhuman primates. The current report describes a case of minimally conjoined omphalopagus rhesus monkey twins that were observed in the breeding colony at the California Regional Primate Research Center. The full‐term nonviable male twins were morphologically normal and united in the umbilical region, involving the liver, xiphoid, umbilicus, body wall, and skin. The umbilical cords were separate, but closely aligned, within an ensheathing amnion; each cord contained two arteries and a vein. The closely associated cords were centrally inserted on a large bidiscoid placenta. There were no gross or histologic abnormalities in the viscera, with the exception of enlargement of the left central liver lobes, which constituted the area of attachment. The cause of death was attributed to asphyxia and trauma experienced during parturition.
The impact of dietary protein intake on serum biochemical and haematological profiles in vervet monkeys
Authors: Johnson Q. , Veith W.J. , Mouton T.
Published: December 2003

This study evaluated the influence of Westernised and traditional African diets on biochemical and haematological profiles in vervet monkeys (Cercopithecus aethiops). Twelve adult male vervet monkeys bred at the Medical Research Council, all over 4 years of age and weighing more than 5 kg each, were divided into two groups of six individuals. These monkeys were raised on a standard in‐house diet post‐weaning, before they were fed for 8 weeks on diets containing milk solids (17.2%) or maize+legume (17.4%), as sources of high crude protein (±3.5 g/kg). High protein diets had no significant effect on serum biochemical indices such as aspartate aminotransferase (AST) and gamma glutamyl transferase (GGT) concentrations (P>0.10). However, alanine aminotransferase (ALT) concentrations were significantly higher during week 8 (P<0.05) for the maize+legume protein group. Alkaline phosphatase (ALP; P<0.07), total protein (P<0.0001), albumin (P<0.02), and bilirubin (P<0.003) were elevated in the milk solids group, while glucose levels were also significantly higher for the milk solids group (P<0.05) between weeks 2 and 6. Elevated protein intake had no significant effect on haematological parameters such as red blood cells (RBC), platelet and white blood cell (WBC) counts, haemoglobin levels and monocyte and neutrophil concentrations (P>0.10). In contrast, serum lymphocyte levels were significantly raised in the maize+legume protein group (P=0.03), whereas values for the haematocrit (P<0.002), mean cell volume (MCV; P<0.03) and mean corpuscular haemoglobin concentration (MCHC; P<0.0001) were higher in the monkeys that were fed the milk solids.  This investigation showed that the type of dietary protein that is consumed may well affect certain biochemical and haematological indices in vervet monkeys. Compared to the group that were given the traditional African food regime, the animals on the Western‐type milk solids diet showed significant elevations in a number of important biological indicators. However, longer‐term studies should be completed in this area if we are to make firmer conclusions regarding the link between the nature of dietary proteins that are consumed and its effect on metabolism.
Expression of CD14, CD16 and CD45RA on monocytes from periodontitis patients
Authors: Nagasawa T. , Kobayashi H. , Aramaki M. , Kiji M. , Oda S. , Izumi Y.
Published: December 2003

Background and objective:  Peripheral blood monocytes are a heterogeneous population, with phenotypes that change on activation or differentiation. Most of the monocytes express lipopolysaccharide (LPS) receptor, CD14 intensely, and do not express Fc gamma receptor III, CD16 (CD14++CD16– monocytes). But monocytes expressing CD16 with reduced CD14 (CD14+CD16+ monocytes) increase in inflammatory diseases as well as sepsis and bacteremia in hemodialysis patients. CD45RA is expressed on activated monocytes, and is regarded as an activation marker of peripheral blood monocytes. The purpose of this study was to determine the phenotypic and functional alteration of monocytes in periodontitis patients.

Methods:  Peripheral blood was collected from 33 aggressive periodontitis patients (22 females, 11 males), 55 chronic periodontitis patients (35 females, 20 males) and 30 healthy subjects (16 females, 14 males), and the expression of CD14, CD16 and CD45RA on monocytes was determined using flow cytometry. The production of interleukin‐6 (IL‐6) by CD16+ and CD16– monocytes stimulated with LPS from Escherichia coli and Actinobacillus actinomycetemcomitans was also examined using flow cytometry.

Results:  The percentage of CD14+CD16+ monocytes was significantly increased in chronic periodontitis patients. Percentage of monocytes expressing CD45RA was significantly increased in aggressive periodontitis patients compared to healthy subjects. CD16+ and CD16– monocytes produced IL‐6 in response to LPS from E. coli and A. actinomycetemcomitans, and the percentage of IL‐6 producing cells was higher in CD16+ monocytes than CD16– monocytes, suggesting that CD14+CD16+ monocytes represent a hyper‐reactive phenotype.

Conclusions:  The present study demonstrated that CD14+CD16+ monocytes and CD45RA+ monocytes were increased in chronic and aggressive periodontitis, respectively. These findings suggest that alteration of monocytes in periodontitis patients could be evaluated by monitoring the surface expression of CD14, CD16 and CD45RA on monocytes.
Long-Term Ecosystem Response to the Exxon Valdez Oil Spill
Authors: Peterson Charles H. , Rice Stanley D. , Short Jeffrey W. , Esler Daniel , Bodkin James L. , Ballachey Brenda E. , Irons David B.
Published: December 2003

The ecosystem response to the 1989 spill of oil from the Exxon Valdez into Prince William Sound, Alaska, shows that current practices for assessing ecological risks of oil in the oceans and, by extension, other toxic sources should be changed. Previously, it was assumed that impacts to populations derive almost exclusively from acute mortality. However, in the Alaskan coastal ecosystem, unexpected persistence of toxic subsurface oil and chronic exposures, even at sublethal levels, have continued to affect wildlife. Delayed population reductions and cascades of indirect effects postponed recovery. Development of ecosystem-based toxicology is required to understand and ultimately predict chronic, delayed, and indirect long-term risks and impacts.
Melt Inclusions in Veins: Linking Magmas and Porphyry Cu Deposits
Authors: Harris Anthony C. , Kamenetsky Vadim S. , White Noel C. , van Achterbergh Esmé , Ryan Chris G.
Published: December 2003

At a porphyry copper-gold deposit in Bajo de la Alumbrera, Argentina, silicate-melt inclusions coexist with hypersaline liquid- and vapor-rich inclusions in the earliest magmatic-hydrothermal quartz veins. Copper concentrations of the hypersaline liquid and vapor inclusions reached maxima of 10.0 weight % (wt %) and 4.5 wt %, respectively. These unusually copper-rich inclusions are considered to be the most primitive ore fluid found thus far. Their preservation with coexisting melt allows for the direct quantification of important ore-forming processes, including determination of bulk partition coefficients of metals from magma into ore-forming magmatic volatile phases.
Enrichment of Gene-Coding Sequences in Maize by Genome Filtration
Authors: Whitelaw C. A. , Barbazuk W. B. , Pertea G. , Chan A. P. , Cheung F. , Lee Y. , Zheng L. , van Heeringen S. , Karamycheva S. , Bennetzen J. L. , SanMiguel P. , Lakey N. , Bedell J. , Yuan Y. , Budiman M. A. , Resnick A. , Van Aken S. , Utterback T. , Riedmuller S. , Williams M. , Feldblyum T. , Schubert K. , Beachy R. , Fraser C. M. , Quackenbush J.
Published: December 2003

Approximately 80% of the maize genome comprises highly repetitive sequences interspersed with single-copy, gene-rich sequences, and standard genome sequencing strategies are not readily adaptable to this type of genome. Methodologies that enrich for genic sequences might more rapidly generate useful results from complex genomes. Equivalent numbers of clones from maize selected by techniques called methylation filtering and High C
0
t
selection were sequenced to generate â¼200,000 reads (approximately 132 megabases), which were assembled into contigs. Combination of the two techniques resulted in a sixfold reduction in the effective genome size and a fourfold increase in the gene identification rate in comparison to a nonenriched library.
Maize Genome Sequencing by Methylation Filtration
Authors: Palmer Lance E. , Rabinowicz Pablo D. , O'Shaughnessy Andrew L. , Balija Vivekanand S. , Nascimento Lidia U. , Dike Sujit , de la Bastide Melissa , Martienssen Robert A. , McCombie W. Richard
Published: December 2003

Gene enrichment strategies offer an alternative to sequencing large and repetitive genomes such as that of maize. We report the generation and analysis of nearly 100,000 undermethylated (or methylation filtration) maize sequences. Comparison with the rice genome reveals that methylation filtration results in a more comprehensive representation of maize genes than those that result from expressed sequence tags or transposon insertion sites sequences. About 7% of the repetitive DNA is unmethylated and thus selected in our libraries, but potentially active transposons and unmethylated organelle genomes can be identified. Reverse transcription polymerase chain reaction can be used to finish the maize transcriptome.
Demographic Threats to the Sustainability of Brazil Nut Exploitation
Authors: Peres Carlos A. , Baider Claudia , Zuidema Pieter A. , Wadt Lúcia H. O. , Kainer Karen A. , Gomes-Silva Daisy A. P. , Salomão Rafael P. , Simões Luciana L. , Franciosi Eduardo R. N. , Cornejo Valverde Fernando , Gribel Rogério , Shepard Glenn H. , Kanashiro Milton , Coventry Peter , Yu Douglas W. , Watkinson Andrew R. , Freckleton Robert P.
Published: December 2003

A comparative analysis of 23 populations of the Brazil nut tree (
Bertholletia excelsa
) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the Amazonian extractive economy.
Transcription-Coupled Events Associating with Immunoglobulin Switch Region Chromatin
Authors: Nambu Yukiko , Sugai Manabu , Gonda Hiroyuki , Lee Chung-Gi , Katakai Tomoya , Agata Yasutoshi , Yokota Yoshifumi , Shimizu Akira
Published: December 2003

Class switch recombination (CSR) at the antibody immunoglobulin locus is regulated by germline transcription (GLT)–coupled modifications in the accessibility of the switch region, where CSR takes place. Here we show that histone acetylation of switch regions is linked to CSR but that histone acetylation cannot alone promote CSR or GLT. Activation-induced cytidine deaminase (AID) specifically associates with the CSR target chromatin in a GLT-coupled manner, which may occur potentially by means of physical interaction between AID and the transcription machinery. These data indicate an important role of GLT in the regulation of chromatin accessibility, strongly suggesting that the target of AID is chromatin DNA. Our results give insights on the role of AID and the regulatory mechanism of CSR.
The Third Autobiography
Authors: Olby Robert
Published: December 2003

The Third Man of the Double Helix
The Autobiography of Maurice Wilkins. Maurice Wilkins. Oxford University Press, Oxford, 2003. 288 pp. £16.99, $27.50. ISBN 0-19-860665-6.

Wilkins offers his perspective on the discovery of the structure of DNA (paying particular attention to his interactions with Rosalind Franklin) and discusses other important developments of 20th-century science.
A C*-ALGEBRAIC FRAMEWORK FOR QUANTUM GROUPS
Authors: MASUDA T. , NAKAGAMI Y. , WORONOWICZ S. L.
Published: December 2003

We develop a general framework to deal with the unitary representations of quantum groups using the language of C*-algebras. Using this framework, we prove that the duality holds in a general context. This extends the framework of the duality theorem using the language of von Neumann algebras previously developed by Masuda and Nakagami.
PHILIPPE NOZIÈRES: FEENBERG MEDALIST 2001: MICROSCOPIC AND PHENOMENOLOGICAL FOUNDATIONS OF THE THEORY OF QUANTUM MANY-BODY SYSTEMS PHILIPPE NOZIÈRES REPLIES
Authors: LEGGETT A. J. , KROTSCHECK E. , NEGELE J. W.
Published: December 2003

The Eighth Eugene Feenberg Medal is awarded to Philippe Nozières in recognition of his many pathbreaking contributions to many-body theory, including

• His definitive work on the properties of the free electron gas, in particular in the region of realistic metallic densities,

• his rigorous development of the theory of a normal Fermi liquid, which provided a firm microscopic foundation for the Landau theory,

• his analysis of the nonequilibrium thermodynamics of 3-He solid-liquid mixtures,

• his exact solution to the X-ray edge problem,

• his elegant formulation of the low-temperature solution to the single-channel Kondo problem in the language of Fermi-liquid theory,

• his introduction of the many-channel problem as a new class of quantum impurity systems, and

• his innovative work on the static and dynamic behavior of the liquid-solid interface.
SKYRMIONS IN QUANTUM HALL SYSTEMS
Authors: WALET NIELS R. , SCHWINDT OLIVER , WEIDIG TOM
Published: December 2003

We discuss the finite density properties of baby- and Quantum-Hall Skyrmions, using a thermodynamic approach, and a related simulated annealing technique. We show how we can find similar behaviour in both models, and also discuss possible extensions.
QUANTUM FRUSTRATED MAGNETS: FROM THEORY TO EXPERIMENTS
Authors: MILA F.
Published: December 2003

This paper presents an overview of the properties predicted and in many cases observed in quantum frustrated magnets. The emphasis will be put on two new compounds which have opened the way to a detailed analysis of two aspects of the problem: (i) Li 2 VOSiO 4, a realisation of the J1 - J2 model on the square lattice in which quantum fluctuations stabilise long-range magnetic order; (ii) Cu 2 Te 2 O 5 Br 2, the first system believed to possess low-lying singlet excitations inside a singlet-triplet gap.
QUANTUM PHASES IN TWO-DIMENSIONAL FRUSTRATED SPIN-1/2 ANTIFERROMAGNETS
Authors: SINDZINGRE P. , LHUILLIER C. , FOUET J.-B.
Published: December 2003

We describe four phases found in two-dimensional quantum antiferromagnets. Two of them display long range order at T = 0: the Néel state and the Valence Bond Crystal. The last two are Spin-Liquids. Properties of these different states are shortly described and likely conditions of their occurrence outlined.
COVARIANT EFFECTIVE FIELD THEORY FOR BULK PROPERTIES OF NUCLEI
Authors: SEROT BRIAN D.
Published: December 2003

Recent progress in Lorentz-covariant quantum field theories of the nuclear many-body problem (quantum hadrodynamics or QHD) is discussed. The importance of modern perspectives in effective field theory and density functional theory for understanding the successes of QHD is emphasised. The inclusion of hadronic electromagnetic structure and of nonanalytic terms in the energy functional is also considered.
RELATIVISTIC MEAN FIELD THEORY FOR UNSTABLE NUCLEI AND SUPERNOVAE
Authors: TOKI HIROSHI
Published: December 2003

We discuss first the properties of unstable nuclei in the framework of the relativistic mean field (RMF) theory. We take the RMF theory as a phenomenological theory with several parameters, whose form is constrained by the successful microscopic theory (RBHF), and whose values are extracted from the experimental data of unstable nuclei. We find the outcome with the use of the parameter sets (TM1 and TMA) is promising in comparison with various experimental data on finite nuclei including unstable ones. We construct then the equation of state of nuclear matter for the use in the description of supernovae. We present also the simulations of supernovae with the supernova newly constructed equation of state in the prompt explosion scenario.
COLOUR SUPERCONDUCTIVITY IN FINITE SYSTEMS
Authors: AMORE P. , BIRSE M. C. , MCGOVERN J. A. , WALET N. R.
Published: December 2003

We have studied the effects of finite size on the two flavor colour superconducting state. Since the baryon number in the BCS state is only fixed on average, we have projected the state over a fixed baryon number. The resulting state has been then projected over a colour-singlet state, by integrating over the colour group manifold. The effects of both projections have been evaluated numerically.
EOS OF NUCLEAR MATTER WITHIN A GENERALISED NJL MODEL
Authors: DA PROVIDÊNCIA CONSTANÇA , DA PROVIDÊNCIA JOÃO , MOSZKOWSKI STEVEN A.
Published: December 2003

We derive the equation of state (EOS) of nuclear matter within a generalised Nambu–Jona–Lasinio (NJL) model which saturates at normal nuclear density, ρ0. Chiral symmetry is restored at ~ 6–7 ρ0. At low densities the model includes clustering and reproduces the properties of nuclear matter namely binding energy and incompressibility. At high densities (ρ>3–4.5 ρ0) quark matter is more stable than nuclear matter. The confinement-deconfinement phase transition is studied.
EXCITATIONS IN CONFINED FERMI FLUIDS
Authors: HERNÁNDEZ E. S.
Published: December 2003

Studies of excitation spectra of Fermi fluids in the presence of various types of spatial symmetry breaking are reviewed. In particular, I discuss the predicted spectra of films of3He adsorbed on planar substrates and of dilute40K gases in magnetic traps. Finally, I anticipate some dynamical aspects of3He gases in onedimensional and quasi-onedimensional adsorbed phases in porous media.
A BIOGRAPHY OF THE COUPLED CLUSTER METHOD
Authors: KÜMMEL HERMANN G.
Published: December 2003

The origins of the coupled cluster method are described. Special attention is paid to the arguments put forward for the exponential structure of the wave functions. Various approximation schemes invented during the last 40 years are presented. The problems arising from these approximations necessarily truncating or destroying the exponential form are discussed and ways to deal with them are described.
THE DIFFUSION QUANTUM MONTE CARLO METHOD: DESIGNING TRIAL WAVE FUNCTIONS FOR NiO
Authors: NEEDS R. J. , TOWLER M. D.
Published: December 2003

A brief overview of the diffusion quantum Monte Carlo method is given. The importance of the trial wave function is emphasised and we discuss how to design satisfactory forms for transition metal monoxides. Some results of a diffusion quantum Monte Carlo study of NiO are reported.
DISSIPATION IN OPEN TWO-LEVEL SYSTEMS: PERTURBATION THEORY AND POLARON TRANSFORMATION
Authors: BRANDES T. , VORRATH T.
Published: December 2003

We compare standard perturbation theory with the polaron transformation for non-linear transport of electrons through a two-level system. For weak electron-phonon coupling and large bias, there is good agreement between both approaches. This regime has recently been explored in experiments in double quantum dots.
TRANSPORT IN QUANTUM WIRES WITH IMPURITIES AT FINITE TEMPERATURE
Authors: KLEIMANN T. , SASSETTI M. , KRAMER B.
Published: December 2003

The temperature dependence of Coulomb blockade peaks of a one dimensional quantum dot is calculated. The Coulomb interaction is treated microscopically using the Luttinger liquid model. The electron interaction is assumed to be non-homogeneous with a maximum strength near the quantum dot. The conductance peaks show non-analytic power law behaviour induced by the interaction. It is shown that there is a crossover in the power law which is related to the inhomogeneity of the interaction.
DYNAMICS OF A LARGE-SPIN-BOSON SYSTEM IN THE STRONG COUPLING REGIME
Authors: VORRATH TILL , BRANDES TOBIAS , KRAMER BERNHARD
Published: December 2003

We investigate collective effects of an ensemble of biased two-level systems interacting with a bosonic bath in the strong coupling regime. The two level systems are described by a large pseudo-spin J. An equation for the expectation value M(t) of the z-component of the pseudo spin is derived and solved numerically for an ohmic bath at T=0. In case of a large cut-off frequency of the spectral function, a Markov approximation is justified and an analytical solution is presented. We find that M(t) relaxes towards a highly correlated state with maximum value ±J for large times. However, this relaxation is extremely slow for most parameter values so as if the system was "frozen in" by interaction with the bosonic bath.
QUANTUM DISORDER OF AN ANTIFERROMAGNETIC SPIN MODEL ON THE SIERPIŃSKI GASKET
Authors: VOIGT ANDREAS , RICHTER JOHANNES
Published: December 2003

We study the ground state magnetic order of the quantum antiferromagnet on the fractal Sierpiński gasket, a system with a dimension between one and two. Using exact diagonalisation we analyse the ground state and thermodynamic properties of small finite systems and calculate data like spin-spin correlations and specific heat. We find arguments that the ground state remains disordered for an XY or Ising like anisotropy in the spin exchange away from the isotropic Heisenberg point.
TOWARD A THEORY OF CHAOS
Authors: SENGUPTA A.
Published: December 2003

This paper formulates a new approach to the study of chaos in discrete dynamical systems based on the notions of inverse ill-posed problems, set-valued mappings, generalized and multivalued inverses, graphical convergence of a net of functions in an extended multifunction space [Sengupta & Ray, 2000] and the topological theory of convergence. Order, chaos and complexity are described as distinct components of this unified mathematical structure that can be viewed as an application of the theory of convergence in topological spaces to increasingly nonlinear mappings, with the boundary between order and complexity in the topology of graphical convergence being the region in (Multi(X)) that is susceptible to chaos. The paper uses results from the discretized spectral approximation in neutron transport theory [Sengupta, 1988, 1995] and concludes that the numerically exact results obtained by this approximation of the Case singular eigenfunction solution is due to the graphical convergence of the Poisson and conjugate Poisson kernels to the Dirac delta and the principal value multifunctions respectively. In (Multi(X)), the continuous spectrum is shown to reduce to a point spectrum, and we introduce a notion of latent chaotic states to interpret superposition over generalized eigenfunctions. Along with these latent states, spectral theory of nonlinear operators is used to conclude that nature supports complexity to attain efficiently a multiplicity of states that otherwise would remain unavailable to it.
ORIGIN OF CHAOS IN A TWO-DIMENSIONAL MAP MODELING SPIKING-BURSTING NEURAL ACTIVITY
Authors: SHILNIKOV ANDREY L. , RULKOV NIKOLAI F.
Published: December 2003

Origin of chaos in a simple two-dimensional map model replicating the spiking and spiking-bursting activity of real biological neurons is studied. The map contains one fast and one slow variable. Individual dynamics of a fast subsystem of the map is characterized by two types of possible attractors: stable fixed point (replicating silence) and superstable limit cycle (replicating spikes). Coupling this subsystem with the slow subsystem leads to the generation of periodic or chaotic spiking-bursting behavior. We study the bifurcation scenarios which reveal the dynamical mechanisms that lead to chaos at alternating silence and spiking phases.