bluuebunny/crossref_metadata_2025 huggingface dataset:
Are Some Risk Comparisons More Effective Under Conflict?: A Replication and Extension of Roth et al.
Authors: Johnson Branden B.
Published: July 2003

Despite many claims for and against the use of risk comparisons in risk communication, few empirical studies have explored their effect. Only one study, published by Roth et al. in this journal in 1990, has tested the 1988 predictions by Covello et al. as to the public's relative preferences for 14 kinds of risk comparisons as they might be used by a factory manager to explain risks of his ethylene oxide plant. That study found no correlations between the Covello predictions and seven different measures of “acceptability” of Covello's examples of each type of comparison. However, two critics of the Roth study, as well as its own authors, suggested that a scenario involving local risks, a conflict‐ridden situation, and a plant manager unknown to the townspeople might better evoke Covello‐like preferences than the distant, calm, friends‐involving scenario used by Roth. The research reported here replicated the Roth study using the same scenario, risk comparison examples, and evaluation measures, and added a second scenario intended to replicate the conditions suggested by critics. Over 200 New Jersey residents answered the study questionnaire. The replication scenario reproduced Roth's results, and the conflict scenario also evoked no rankings correlated with Covello's predictions. Furthermore, neither agreement nor disagreement with five statements representing “conflict”—respondents' reports that the industrial‐plant scenario made them angry, they lived near industry, they were concerned about industrial risks, people in their home town were angry about industrial pollution, and they worried “frequently” about long‐term effects of pollution—correlated with Covello's predictions. Over half of all ratings ascribed to the comparisons in aggregate were positive, and most detailed comments offered by respondents also were positive, despite many criticisms and suggestions for their improvement. The wide variability in individuals' rankings also undermines the notion of any single ranking of preferred comparisons. These findings have implications for use of risk comparisons, but also reveal the inaccuracy of the field's assumptions about public reaction to industrial risk information, including risk comparison.
Risk Target: An Interactive Context Factor in Risk Perception
Authors: Hermand Danièle , Karsenty Serge , Py Yves , Guillet Laurent , Chauvin Bruno , Simeone Arnaud , Teresa María , Sastre Muñoz , Mullet Etienne
Published: July 2003

The effect of specification of the target on risk evaluation was examined. A whole set of hazards, covering most of the domains, were considered: common individual hazards, outdoor activities, medical care, public transportation, energy production, pollutants, sex, deviance, and addictions. Three human targets were introduced: personal health risk (including personal risk of death), health risk for people in the country, and health risk for people in the world. The basic design was a between‐subjects design. The first hypothesis was that risk judgments made in the “world” condition should be higher than risk judgments made in the “country” condition, and risk judgments made in this condition should be higher than risk judgments made in the “personal” condition. This is what was observed. The second hypothesis was that the target effect should differ as a function of the kind of hazards considered. This also is what was observed. In two domains— pollutants, and deviance, sex, and addictions—the target effect was important. It corresponded to about one‐tenth of the response scale. In the four remaining domains, the target effect was unimportant or absent.
Polarization in the Reaction to Health‐Risk Information: A Question of Social Position?
Authors: Lindbladh Eva , Lyttkens Carl Hampus
Published: July 2003

Dissemination of risk information is ubiquitous in contemporary society. We explore how individuals react in everyday life to health‐risk information, based on what they report in personal interviews. Health‐risk information was without exception recognized as unstable and inconsistent. This conformity, however, did not extend to the narratives regarding how health‐risk information should be handled. Two opposite positions (ideal‐typical strategies) are presented. Either you tend to process and evaluate new information or you tend to ignore it as a whole. Our attempt to reveal the underlying rationality in these two very different approaches involved the exploration of three different avenues of interpretation and brings together two scientific paradigms—economics and sociology—that provide the framework for our analysis. First, we suggest that a greater long‐term experience of explicit choice implies that this kind of action becomes more natural and less resource consuming, whereas a reliance on habits in daily life—a natural adjustment to a lack of resources—makes it is more costly to bother about new information. Second, with fewer resources in the short run, fewer opportunities to mitigate bad outcomes, and greater exposure to social and material risks, one is less likely to devote resources to deal with health‐risk information. Third, there are several possible links between a low propensity to take account of risk information and a high relative importance of genuine uncertainty in one's life. These theoretical perspectives provide a viable set of hypotheses regarding mechanisms that may contribute to social differences in the response to health‐risk information.
Housing and Mental Health: A Review of the Evidence and a Methodological and Conceptual Critique
Authors: Evans Gary W. , Wells Nancy M. , Moch Annie
Published: July 2003

Despite the fact that people invest more financial, temporal, and psychological resources in their homes than in any other material entity, research on housing and mental health is remarkably underdeveloped. We critically review existing research on housing and mental health, considering housing type (e.g., single‐family detached versus multiple dwelling), floor level, and housing quality (e.g., structural damage). We then discuss methodological and conceptual shortcomings of this literature and provide a theoretical framework for future research on housing quality and mental health.
Housing as Health Capital: How Health Trajectories and Housing Paths Are Linked
Authors: Smith Susan J. , Easterlow Donna , Munro Moira , Turner Katrina M.
Published: July 2003

This article explores the relationships between housing and health inequalities. It locates housing within a network of health resources that can either promote well‐being or increase susceptibility to disease. Housing thereby contributes to the accumulation, or depletion, of the health capital of individuals and communities. Qualitative interviews in three British regions help specify the links between health capital, on the one hand, and the network of resources, environments, events, institutions, and social relations comprising the housing system, on the other. The findings show why, from a health capital/health‐resources‐network perspective, a segment of the housing system (owner‐occupation) that generally appears therapeutic can have the opposite effect for people whose resilience is low or whose health is in decline.
Poverty, Housing Niches, and Health in the United States
Authors: Saegert Susan , Evans Gary W.
Published: July 2003

Drawing on psychological, health, and social science literature, a housing niche model is developed that focuses on (a) housing markets and other societal processes that constrain residential choice, (b) effects of residential environments on health and access to human and social capital, and (c) family dynamic effects on health and the intergenerational consequences of particular housing niches for future health and housing choices. The model requires the examination of cumulative risks, mediating and moderating processes, and the use of multilevel statistical models. The health consequences of existing housing policies are explored and future directions for research and policy suggested.
Focus on Home: What Time‐Use Data Can Tell About Caregiving to Adults
Authors: Michelson William , Tepperman Lorne
Published: July 2003

Care by adults to other adults is being increasingly transferred from formal public institutions to the private home. To learn more about the nature and situation of Canadian adults providing care at home to other adults, we analyzed data from Statistics Canada's 1998 social survey of 10,749 persons. Data included time‐use and respondents' sociodemographic, cultural, work, and leisure characteristics, as well as outcome factors. We found 212 respondents (about 2%) providing personal, medical, or other care to other household adults on the day studied. We compared them to those not found to provide these services. The article explores time‐use trade‐offs, feelings of stress, and the ramifications of gender, age, and paid work in this newly reemerging use of household space.
Residence in the Social Ecology of Stress and Restoration
Authors: Hartig Terry , Johansson Gunn , Kylin Camilla
Published: July 2003

We relate residence to health within a social ecological model of stress and restoration. As an isolated setting and in relation to other everyday settings, we discuss the residence in terms of demands, coping resources and responses, and opportunities for restoration. Our model indicates how processes operating above the household level can affect health by modifying the quantity, quality, and distribution of demands, resources, and restoration opportunities within and across the settings of everyday life, including the residence. We illustrate some of these social ecological dynamics with the case of home‐based telework. Concluding, we discuss the utility of the model for environmental interventions intended to alleviate health‐threatening chronic stress.
Comment: Housing Policy and Health
Authors: Catalano Ralph , Kessell Eric
Published: July 2003

We summarize and comment on the policy sections of the articles in this issue concerned with the health effects of residential environments. We review the implications in the context of public policies implemented over at least the last century to improve the least, as well as most, expensive housing. We make the argument that public policy can reduce but not eliminate the contribution of housing to the differences in health between the wealthy and poor. We conclude that the applied value of work such as that presented in this issue arises from its contribution to sustaining the improvements in health enjoyed over the last century, not from whether it helps eliminate the gap in health between the poor and wealthy.
Disparities in Educational Opportunities and Outcomes: What Do We Know and What Can We Do?
Authors: Maruyama Geoffrey
Published: July 2003

This article examines disparities based upon poverty and race/ethnicity. After framing the issues by looking at national, state, and local data, it illustrates ways that social scientists can be involved in shaping educational practices and policies, focusing on the types of skills that are useful and on ways of thinking about the types of collaboration that are needed. Skills discussed are methodological as well as substantive; both types draw from existing knowledge bases. For collaboration, the model described is that of action research. Approaches are illustrated through personal examples drawn from collaborations with urban public schools. They include defining expected growth for students at different achievement levels, school accountability issues, and setting up long‐term collaboration.
Angiotensin AT1 Receptor Antagonist Losartan and the Defence Reaction in the Anaesthetised Rat. Effect on the Carotid Chemoreflex
Authors: Rocha Isabel , Brás‐Rosário Luís , Amparo‐Barros M. , Silva‐Carvalho Luís
Published: July 2003

Modulation at the level of the nucleus tractus solitarii (NTS) appears to be an effective way of controlling cardiovascular reflexes. Angiotensin II acting on angiotensin AT1 receptors at the central nervous system appears to have an important role in these modulatory processes. The hypothalamic defence area (HDA) is a potential source of descending fibres containing angiotensin II that innervate the NTS. We investigated the effect of AT1 receptor blockade in the NTS on the response to stimulation of HDA in anaesthetised rats treated with the neuromuscular blocking agent pancuronium bromide. The characteristic increase in heart rate, blood pressure and phrenic nerve activity evoked by electrical stimulation of HDA is decreased by the microinjection of the AT1 receptor antagonist losartan into the NTS and the cardiovascular response to carotid body chemical stimulation is also reduced. These results support the hypothesis that AT1 receptors in the NTS play a role in the modulation of cardiovascular reflexes, and modify the influence exerted on the processing of these reflexes by other areas of the central nervous system.
Differential Chronotropic and Dromotropic Responses to Focal Stimulation of Cardiac Vagal Ganglia in the Rat
Authors: Sampaio Karla N. , Mauad Hélder , Spyer K. Michael , Ford Timothy W.
Published: July 2003

Vagal cardioinhibition is exerted through a reduction not only in the heart rate but also in the rate of propagation of the cardiac action potential and in myocardial contractility. In several species, such effects can be produced independently by selective activation of ganglia in identified ‘fat pads’. In this study we investigate differential control of heart rate and atrioventricular conduction by two ganglionic clusters in the rat, a species increasingly important in studies of cardiovascular control. Epicardial sites producing low‐threshold changes in P‐P and P‐R interval of the ECG in an arterially perfused preparation were explored with concentric bipolar stimulating electrodes. Stimulation sites centred on two principal ganglia, the sinoatrial (SA) ganglion at the junction of the right superior vena cava and right atrium, and the atrioventricular (AV) ganglion at the junction of the inferior pulmonary veins and left atrium. Stimulation of the SA ganglion decreased heart rate in all preparations, with little or no effect on AV conduction in one‐third. Stimulation of the AV ganglion consistently slowed conduction without eliciting a comparable bradycardia. Responses survived blockade of ganglionic transmission by trimetaphan, with an enhanced chronotropic selectivity to SA ganglion stimulation, suggesting that co‐excitation of preganglionic elements en passant may have contributed to the earlier mixed responses. Effective stimulation sites were precisely circumscribed and corresponded to principal ganglionic clusters confirmed histologically. We conclude that cardiac vagal ganglia in the rat show a topographical functional organisation and are amenable to investigation using the arterially perfused preparation.
Heart Rate Variability and Endogenous Sex Hormones During the Menstrual Cycle in Young Women
Authors: Leicht Anthony S. , Hirning David A. , Allen Graham D.
Published: July 2003

To our knowledge, the relationship between all four endogenous female sex hormones and resting cardiac autonomic function has not been studied. The aim of the current study was to examine the association between the normal endogenous levels of oestrogen (17β‐oestradiol), progesterone, luteinising hormone and follicle‐stimulating hormone and heart rate variability (HRV) during the menstrual cycle in young eumenorrheic women. Ten healthy, young, female subjects volunteered for this study. HRV and endogenous hormone levels were recorded at three phases of the menstrual cycle: menses (day 3.8 ± 0.5), ovulation (day 15.8 ± 0.7) and luteal (day 22.1 ± 0.4) to ensure HRV recordings at times of low (menses) and high (ovulation and luteal) hormonal influence. Heart rate recordings were obtained from supine resting subjects and analysed on a Holter analysis system. Total power (TP, 0‐1.0 Hz), low frequency (LF, 0.041‐0.15 Hz), high frequency (HF, 0.15‐0.80 Hz) and LF/HF components of HRV were examined. Despite a significantly greater HR at ovulation and normal cyclic variations in all endogenous sex hormone levels, no measure of HRV was significantly different between menstrual cycle phases. Significant correlations between oestrogen levels and absolute measures of HRV at ovulation were identified. The results of the current study demonstrated that the normal cyclic variations in endogenous sex hormone levels during the menstrual cycle were not significantly associated with changes in cardiac autonomic control as measured by HRV. Significant correlation between peak oestrogen levels and HRV measures at ovulation provided further support for the reported cardioprotective effects of oestrogen in healthy females.
Activation of the Renin‐Angiotensin System Contributes to the Peripheral Vasoconstriction Reflexly Caused by Stomach Distension in Anaesthetized Pigs
Authors: Molinari C. , Battaglia A. , Grossini E. , Florio S. , Mary D. A. S. G. , Vassanelli C. , Vacca G.
Published: July 2003

Gastric distension in anaesthetized pigs reflexly elicits peripheral vasoconstriction and an increase in plasma renin activity (PRA), with vagal afferent and sympathetic efferent limbs. The aim of the present study was to quantify the contribution of the renin‐angiotensin system to the peripheral vasoconstriction. In pigs anaesthetized with α‐chloralose, changes in anterior descending coronary, superior mesenteric and left external iliac blood flow caused by stomach distension before and after blockade of angiotensin II receptors with losartan were assessed using electromagnetic flowmeters. Gastric distension for periods of 30 min was performed by injecting 0.8 l warm Ringer solution into balloons positioned within the viscus. Changes in heart rate and renal blood flow were prevented by atrial pacing and injection of phentolamine into the renal arteries, and changes in regional perfusion pressure and in baroreceptor activity were minimized by aortic constriction and denervation of the carotid sinuses. PRA was assessed by radioimmunoassay of angiotensin I. Before blockade of angiotensin II receptors by administration of losartan, stomach distension decreased coronary blood flow by 14.2% in six pigs and mesenteric and iliac blood flow by 11% and 17.3%, respectively, in another six pigs. After administration of losartan, these decreases were significantly reduced to 7.4%, 6.8% and 8.7%, respectively. The above responses were abolished by bilateral section of the subdiaphragmatic vagal nerves. These results show that the peripheral vasoconstriction reflexly caused by stomach distension was significantly contributed to by the concomitant activation of the renin‐angiotensin system.
Age‐Related Analysis of Glucose Metabolism in Spontaneously Hypertensive and Normotensive Rats
Authors: Natalucci Silvia , Ruggeri Piero , Cogo Carla Emilia , Picchio Viviana , Brunori Andrea , Burattini Roberto
Published: July 2003

This study was designed to investigate the effect of both hypertension and ageing on the efficiency of glucose metabolism. A 12‐sample, 120 min intravenous glucose tolerance test (IVGTT) was applied to 36 rats: two groups of nine young (12 weeks) spontaneously hypertensive and Wistar Kyoto rats (Y‐SHR and Y‐WKY group, respectively) and two groups of nine old (40 weeks) SHR and WKY rats (O‐SHR and O‐WKY group, respectively). Insulinaemia and glycaemia data were interpreted in terms of estimates of glucose effectiveness, SG, and insulin sensitivity, SI, provided by the minimal model of glucose kinetics. The possible link between insulin resistance and hypertension was investigated by comparing Y‐SHR vs. Y‐WKY and O‐SHR vs. O‐WKY groups. Comparison of O‐SHR vs. Y‐SHR and O‐WKY vs. Y‐WKY groups enabled us to investigate the role of age in the development of abnormalities in glucose metabolism. No significant differences (P > 0.05) were observed in the mean SG and SI estimates between SHR and age‐matched WKY groups. This finding indicates that exposure of SHR to high blood pressure levels does not necessarily lead to the development of insulin resistance and impaired glucose effectiveness. Similarly, no significant differences (P > 0.05) were observed in SG and SI estimates between old and young SHR and WKY groups. This finding indicates that, in this animal model of hypertension, insulin sensitivity and glucose effectiveness do not even deteriorate with ageing.
[Ca2+]i Oscillations Induced by High [K+]o in Acetylcholine‐Stimulated Rat Submandibular Acinar Cells: Regulation by Depolarization, cAMP and Pertussis Toxin
Authors: Yoshida Hideyo , Marunaka Yoshinori , Nakahari Takashi
Published: July 2003

Maintaining the extracellular K+ concentration ([K+]o) between 15 and 60 mM induced oscillations in the intracellular Ca2+ concentration ([Ca2+]i) in rat submandibular acinar cells during stimulation with acetylcholine (ACh, 1 μM). These [Ca2+]i oscillations were also induced by 1 μM thapsigargin and were inhibited by 50 μM La3+, 1 μM Gd3+, or the removal of extracellular Ca2+, indicating that the [Ca2+]i oscillations were generated by store‐operated Ca2+ entry (SOC). The frequency of the ACh‐evoked [Ca2+]i oscillations increased from 0.8 to 2.3 mHz as [K+]o was increased from 15 to 50 mM. TEA (an inhibitor of K+ channels) also induced [Ca2+]i oscillations at [K+]o of 4.5 or 7.5 mM in ACh‐stimulated cells. These data suggest that depolarization causes [Ca2+]i to oscillate in ACh‐stimulated submandibular acinar cells. Pertussis toxin (PTX, an inhibitor of G proteins) caused [Ca2+]i to be sustained at a high level in ACh‐stimulated cells at 25 mM or 60 mM [K+]o. This suggests that the [Ca2+]i oscillations are generated by a periodic inactivation of the SOC channels via PTX‐sensitive G proteins, which are stimulated by depolarization. Moreover, in the presence of DBcAMP or forskolin which accumulated cAMP the frequency of the [Ca2+]i oscillations remained constant (approximately 1.2 mHz) when [K+]o was maintained in the range 25‐60 mM. Based on these observations in ACh‐stimulated submandibular acinar cells, we conclude that depolarization stimulates the PTX‐sensitive G proteins, which inactivate the SOC channels periodically ([Ca2+]i oscillation), while hyperpolarization or PTX inhibits the G proteins, maintaining the activation of the SOC channels. Accumulation of cAMP is likely to modulate the PTX‐sensitive G proteins.
Expression of the Secondary Sigma Factor σ
X
in
Streptococcus pyogenes
Is Restricted at Two Levels
Authors: Opdyke Jason A. , Scott June R. , Moran, Charles P.
Published: July 2003

Secondary RNA polymerase sigma factors in many bacteria are responsible for regulating a vast range of processes including virulence. A protein (σ
X
) in the gram-positive human pathogen
Streptococcus pyogenes
(the group A
Streptococcus
or GAS) was recently shown to function in vitro as a secondary sigma factor. We report here the isolation of a mutant in which both
sigX
genes are inactivated, show that σ
X
functions in GAS cells, and show that the amount of σ
X
is controlled at two levels. Primer extension analysis indicates that
sigX
transcription is low in GAS cells grown in Todd-Hewitt yeast broth, and immunoblot assays with a σ
X
-specific polyclonal antibody demonstrate that the protein does not accumulate in these cells. To increase the level of
sigX
transcription in GAS, we constructed a strain that constitutively expresses the
sigX
gene from a heterologous promoter. Expression of
sigX
from this promoter led to transcription of the σ
X
-dependent
cinA
promoter in GAS cells. We found that expression of the
sigX
gene in a
clpP
mutant strain resulted in greater accumulation of σ
X
protein, which resulted in higher levels of transcription from the σ
X
-dependent promoters
cinA
,
smf
, and
cglA
. In addition, a
clpP
mutant containing
sigX
only at its wild-type loci on the chromosome generated more transcription from the σ
X
-dependent
cinA
promoter than did the wild-type parental strain. Therefore, σ
X
activity in GAS is limited by low-level transcription of the
sigX
structural genes and by
clpP
, which appears to negatively regulate σ
X
accumulation.
PlmA, a New Member of the GntR Family, Has Plasmid Maintenance Functions in
Anabaena
sp. Strain PCC 7120
Authors: Lee Martin H. , Scherer Michael , Rigali Sébastien , Golden James W.
Published: July 2003

The filamentous cyanobacterium
Anabaena
(
Nostoc
) sp. strain PCC 7120 maintains a genome that is divided into a 6.4-Mb chromosome, three large plasmids of more that 100 kb, two medium-sized plasmids of 55 and 40 kb, and a 5.5-kb plasmid. Plasmid copy number can be dynamic in some cyanobacterial species, and the genes that regulate this process have not been characterized. Here we show that mutations in an open reading frame,
all1076
, reduce the numbers of copies per chromosome of several plasmids. In a mutant strain, plasmids pCC7120δ and pCC7120ζ are both reduced to less than 50% of their wild-type levels. The exogenous pDU1-based plasmid pAM1691 is reduced to less than 25% of its wild-type level, and the plasmid is rapidly lost. The peptide encoded by
all1076
shows similarity to members of the GntR family of transcriptional regulators. Phylogenetic analysis reveals a new domain topology within the GntR family. PlmA homologs, all coming from cyanobacterial species, form a new subfamily that is distinct from the previously identified subfamilies. The
all1076
locus, named
plmA
, regulates plasmid maintenance functions in
Anabaena
sp. strain PCC 7120.
Characterization of a New LexA Binding Motif in the Marine Magnetotactic Bacterium Strain MC-1
Authors: Fernández de Henestrosa Antonio R. , Cuñé Jordi , Mazón Gerard , Dubbels Bradley L. , Bazylinski Dennis A. , Barbé Jordi
Published: July 2003

MC-1 is a marine, magnetotactic bacterium that is phylogenetically associated with the alpha subclass of theProteobacteriaand is the first and only magnetotactic coccus isolated in pure culture to date. By using a TBLASTN search, alexAgene was identified in the published genome of MC-1; it was subsequently cloned, and the protein was purified to >90% purity. Results from reverse transcription-PCR analysis revealed that the MC-1lexAgene comprises a single transcriptional unit with two open reading frames encoding proteins of unknown function and with arumA-like gene, a homologue of theEscherichia coli umuDgene. Mobility shift assays revealed that this LexA protein specifically binds both to its own promoter and to that of theumuDCoperon. However, MC-1 LexA does not bind to the promoter regions of other genes, such asrecAanduvrA, that have been previously reported to be regulated by LexA in bacterial species belonging to the alpha subclass of theProteobacteria. Site-directed mutagenesis of both thelexAandumuDCoperator regions demonstrated that the sequence CCTN10AGG is the specific target motif for the MC-1 LexA protein.
Cell Death in
Pseudomonas aeruginosa
Biofilm Development
Authors: Webb Jeremy S. , Thompson Lyndal S. , James Sally , Charlton Tim , Tolker-Nielsen Tim , Koch Birgit , Givskov Michael , Kjelleberg Staffan
Published: July 2003

Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of
Pseudomonas aeruginosa
occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids. However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of
P. aeruginosa
during the normal course of development. Cell death occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development thereafter, a bacteriophage capable of superinfecting and lysing the
P. aeruginosa
parent strain was detected in the fluid effluent from the biofilm. The bacteriophage implicated in biofilm killing was closely related to the filamentous phage Pf1 and existed as a prophage within the genome of
P. aeruginosa
. We propose that prophage-mediated cell death is an important mechanism of differentiation inside microcolonies that facilitates dispersal of a subpopulation of surviving cells.
Integration and Distribution of
Lactobacillus johnsonii
Prophages
Authors: Ventura Marco , Canchaya Carlos , Pridmore David , Berger Bernard , Brüssow Harald
Published: July 2003

In
Lactobacillus johnsonii
strain NCC533, two prophages were integrated into tRNA genes and one was disrupted by integration. In a survey, the prophages were restricted to strains sharing an essentially identical restriction pattern. Microarray analysis showed that the prophage DNA represents about 50% of the NCC533 strain-specific DNA.
Analysis of the Interaction between the Transcription Factor σ
G
and the Anti-Sigma Factor SpoIIAB of
Bacillus subtilis
Authors: Evans Louise , Clarkson Joanna , Yudkin Michael D. , Errington Jeff , Feucht Andrea
Published: July 2003

The activation of σ
G
, a transcription factor, in
Bacillus subtilis
is coupled to the completion of engulfment during sporulation. SpoIIAB, an anti-sigma factor involved in regulation of σ
F
, is also shown to form a complex with σ
G
in vitro. SpoIIAA, the corresponding anti-anti-sigma factor, can disrupt the SpoIIAB:σ
G
complex, releasing free σ
G
. The data suggest the existence of an as-yet-unknown mechanism to keep σ
G
inactive prior to engulfment.
Universal Features of the Holographic Duality: Conformal Anomaly and Brane Gravity Trapping from 5D Ads Black Hole
Authors: Nojiri S. , Odintsov S. D.
Published: July 2003

We calculate the holographic conformal anomaly and brane Newton potential when bulk is 5d ads black hole. It is shown that such anomaly is the same as in the case of pure ads or (asymptotically) ds bulk spaces, i.e. it is (bulk) metric independent one. While Newton potential on the static brane in ads bh is different from the one in pure ads space, the gravity trapping still occurs for two branes systems. This indicates to metric independence of gravity localization.
Advances in String Theory in Curved Backgrounds: A Synthesis Report
Authors: Sanchez N. G.
Published: July 2003

A synthetic report of the advances in the study of classical and quantum string dynamics in curved backgrounds is provided, namely : the new feature of Multistring solutions; the mass spectrum of Strings in Curved backgrounds; The effect of a Cosmological Constant and of Spacial Curvature on Classical and Quantum Strings; Classical splitting of Fundamental Strings; The General String Evolution in constant Curvature Spacetimes; The Conformal Invariance Effects; Strings on plane fronted and gravitational shock waves, string falling on spacetime singularities and its spectrum.

New Developments in String Gravity and String Cosmology are reported: String driven cosmology and its Predictions; The primordial gravitational wave background; Non-singular string cosmologies from Exact Conformal Field Theories; Quantum Field Theory, String Temperature and the String Phase of de Sitter space-time; Hawking Radiation in String Theory and the String Phase of Black Holes; New Dual Relation between Quantum Field Theory regime and String regime and the "QFT/String Tango"; New Coherent String States and Minimal Uncertainty Principle in string theory.
Peierls Brackets in Field Theory
Authors: Bimonte G. , Esposito G. , Marmo G. , Stornaiolo C.
Published: July 2003

Peierls brackets are part of the space-time approach to quantum field theory, and provide a Poisson bracket which, being defined for pairs of observables which are group invariant, is group invariant by construction. It is therefore well suited for combining the use of Poisson brackets and the full diffeomorphism group in general relativity. The present paper provides an introduction to the topic, with applications to gauge field theory.
On the Topology of Configurations of Gauge Fields and Higgs Fields
Authors: Chaves R.
Published: July 2003

Starting with the topological classification of gauge fields on the sphere (Dirac monopoles) and of Higgs vacuum configurations (through the second homotopy group of the space of vacuum states), the features of minimum energy solutions to gauge theories with spontaneous symmetry breaking and in the presence of singularities (monopoles) are deduced. For each theory, this analysis reveals whether a monopole can exist isolated or must be attached to a massive string and how its flux must be distributed.
Quantum Effects in the Spacetime of a Magnetic Flux Cosmic String
Authors: Guimarães M. E. X. , Oliveira A. L. N.
Published: July 2003

In this work we compute the vacuum expectation values of the energy-momentum tensor and the average value of a massive, charged scalar field in the presence of a magnetic flux cosmic string for both zero- and finite-temperature cases.
Quantization in AdS and the AdS/CFT Correspondence
Authors: Rivelles V. O.
Published: July 2003

The quantization of a scalar field in Ads leads to two kinds of normalizable modes, usually called regular and irregular modes. The regular one is easily taken into account in the standard prescription for the AdS/CFT correspondence. The irregular mode requires a modified prescription which argue is not completely satisfactory. We discuss an alternative quantization in AdS which incorporates boundary terms in a natural way. Within this quantization scheme we present an improved prescription for the AdS/CFT correspondence which can be applied to both, regular and irregular modes. Boundary conditions other than Dirichlet are naturally treated in this new improved setting.
Topological Yang-Mills Theories and their Observables: A Superspace Approach
Authors: Boldo J. L. , Constantinidis C. P. , Piguet O. , Gieres F. , Lefrançois M.
Published: July 2003

Witten's observables of topological Yang-Mills theory, defined as classes of an equivariant cohomology, are re-obtained as the BRST cohomology classes of a superspace version of the theory.
On the Octonionic Superconformal M-Algebra
Authors: Toppan F.
Published: July 2003

It is shown that besides the standard real algebraic framework for M-theory a consistent octonionic realization can be introduced. The octonionic M-superalgebra and superconformal M-algebra are derived. The first one involves 52 real bosonic generators and presents a novel and surprising feature, its octonionic M5 (super-5-brane) sector coincides with the M1 and M2 sectors. The octonionic superconformal M-algebra is given by OSp(1,8∣O) and admits 239 bosonic and 64 fermionic generators.
Dirac Monopoles in the Ernst–Schwarzschild Spacetime
Authors: Bytsenko A. A. , Goncharov Yu. P.
Published: July 2003

It is discussed that the Ernst–Schwarzschild metric describing a nonrotating black hole in the external magnetic field admits the solutions of the Dirac monopole types for the corresponding Maxwell equations. The given solutions are obtained in explicit form and a possible influence of the conforming Dirac monopoles on Hawking radiation is also outlined.
Unexpected Applications of Hill's Differential Equations in Quantum Field Theory and Cosmology
Authors: Mostepanenko V. M.
Published: July 2003

The effect of the exponential pair creation from vacuum by the external field periodic in time is discussed. Two prospective applications of this physical effect in quantum field theory and in inflationary cosmology are considered. Being a nontrivial example of a parametric resonance, the effect of exponential pair creation may serve as an illustration of the effectiveness of mathematics in physical theory.
How Far does the Analogy Between Causal Horizon-Induced Thermalization with the Standard Heat Bath Situation go?
Authors: Schroer B.
Published: July 2003

After a short presentation of KMS states and modular theory as the unifying description of thermalizing systems we propose the absence of transverse vacuum fluctuations in the holographic projections as the principle reason for an area behavior (the transverse area) of localization entropy as opposed to the volume dependence of ordinary heat bath entropy. Thermalization through causal localization is not a property of QM but results from the omnipresent vacuum polarization in QFT and does not require a Gibbs type ensemble avaraging (coupling to a heat bath).
Heat Kernel Expansions in the Case of Conic Singularities
Authors: Seeley R.
Published: July 2003

For positive elliptic differential operators Δ, the asymptotic expansion of the heat trace tr(e-tΔ) and its related zeta function ζ(s, Δ) = tr(Δ-s) have numerous applications in geometry and physics. This article discusses the general nature of the boundary conditions that must be considered when there is a singular stratum, and presents three examples in which a choice of boundary conditions at the singularity must be made. The first example concerns the signature operator on a manifold with a singular stratum of conic type. The second concerns the "Zaremba problem" for a nonsingular manifold with smooth boundary, posing Dirichlet conditions on part of the boundary and Neumann conditions on the complement; the intersection of these two regions can be viewed as a singular stratum of conic type, and a boundary condition must be imposed along this stratum. The third example is a one-dimensional manifold where the operator at one end has a singularity like that in conic problems, and the choice of boundary conditions affects not just the residues at the poles of the zeta function, but also the very location of the poles
A Zeta Function for the BTZ Black Hole
Authors: Williams F. L.
Published: July 2003

For the three-dimensional BTZ black hole we consider a Selberg type zeta function. We indicate how special values of its logarithm correspond to certain thermodynamic quantities associated with the black hole.
Characterization of Argon Plasma by Use of Optical Emission Spectroscopy and Langmuir Probe Measurements
Authors: Qayyum Abdul , Ikram M. , Zakaullah M. , Waheed A. , Murtaza G. , Ahmad Riaz , Majeed Asif , Khattak N. A. D. , Mansoor K. , Chaudhary Khaliq A.
Published: July 2003

Spectroscopic and Langmuir probe measurements are presented to characterize the argon glow discharge plasma generated by a cost-effective 50 Hz AC power source. Optical emission spectra (400–700 nm) are recorded for different gas flow rates and filling pressures at constant power level. The plasma parameters (electron temperature and density) are deduced from the relative intensities of Ar-I and Ar-II lines. The variation in the intensity ratio of the selected emission lines, electron temperature and density is studied as a function of gas flow rate and filling pressure. Slight increase in the intensity ratio I2(426.62 nm )/I1(404.44 nm ) of the emission lines is observed whereas the electron temperature and density are found to decrease with increase in gas flow rate and filling pressure.
Characterization of B4C and LaB6 by Ultrasonics and X-Rays Diffraction
Authors: Lemis-Petropoulos P. , Kapaklis V. , Peikrishvili A. B. , Politis C.
Published: July 2003

A laboratory ultrasound technique has been developed to measure the longitudinal velocity of sound in high purity and density boron carbide and lanthanum hexaboride materials prepared by shock wave compression. Using the measured value of the longitudinal velocity of sound υL, we have calculated the Young's modulus E, the Bulk modulus K, the Shear modulus G and the Poisson's ratio ν. X-rays diffraction has also been carried out on these materials.
Necessary Conditions for Multistationarity and Stable Periodicity
Authors: Snoussi El Houssine
Published: July 2003

We show in this paper that, for a differential system defined by a quasi-monotonous function f (with constant sign partial derivatives) the existence of a positive loop in the interaction graph associated to the Jacobian matrix of f is a necessary condition for multistationarity, and the existence of a negative loop comprising at least two elements is a necessary condition for stable periodicity. This gives a formal proof of R.Thomas's conjectures.
Characterization of Base Periodicities in Protein-Coding Genes
Authors: Jackson Julius H. , George Roy , Adeyemi Hezekiah O. , Winrow Michael A. , Herring Patricia A. , Caguiat Jonathan J. , Mulks Charles F. , Srikanth Radhakrishnan , Harrison Scott H. , Mickens Ronald E.
Published: July 2003

A Fourier Transform of Equal Symbols (FTES) was applied as a spectral density analysis method to identify DNA bases that repeat at any frequency in selected protein-coding genes. The analysis especially focused on identification of bases responsible for the dominant signal at frequency f=1/3 found in all protein-coding genes. The study included homologous sequences from two gene families and multiple unrelated sequences from single organisms. No signal pattern or spectrum specifically characterized either gene family. However, the patterns of bases comprising the signal at f=1/3 suggested the presence of a genome-specific label for protein-coding genes from the same genome. Data suggest that three factors form the informational basis for the signal structure at f=1/3: (1) codon base positional bias; (2) codon preference; and (3) codon arrangement. Quantitative measure of the contribution of each base to the period-3 signal suggests a basis to distinguish protein-coding genes from different organisms. Application of the FTES analysis characterized genes from Escherichia coli as different from the genes from Pseudomonas aeruginosa. Preliminary analyses of genes from these and three other bacteria by artificial neural nets, using FTES parameters, support our suggestion that the period-3 informational structure contains labels for the genomic origins of protein-coding genes. FTES analysis alone or in combination with other informational measures may reveal pathways and processes of gene flow into and through natural systems of microbial cell populations.
Immunotherapy of HIV-1 Infection
Authors: Kirschner Denise E. , Webb G. F.
Published: July 2003

A number of lines of evidence suggest that immunotherapy with the cytokine interleukin-2 (IL-2) may boost the immune response to fight HIV infection. CD4 + T cells, the cells which orchestrate the immune response, are also the cells that become infected by the HIV virus. These cells use cytokines as signaling mechanisms for immune-response stimulation, growth and differentiation. Since CD4 + T cells are hampered due to HIV infection, normal signaling, and the resulting cascade, may not occur. Introduction of IL-2 into the system can restore or enhance these effects. We illustrate, through mathematical modeling, the effects of IL-2 treatment on an HIV-infected patient. With good comparison to existing clinical data, we can better understand what mechanisms of immune-viral dynamics are necessary to produce the typical disease dynamics.
Explicit Solutions for the Stability of No-Tension Beam-Columns
Authors: de Falco A. , Lucchesi M.
Published: July 2003

This work concerns the stability of rectangular cross-sectional piles made of a no-tension material and subjected to an axial load acting at the extremities within the middle third of the cross section. The resulting differential equations are solved, and an explicit relation between the load and a suitable deformability parameter obtained.
Derivation of New Transcendental Member Stiffness Determinant for Vibrating Frames
Authors: Williams F. W. , Kennedy D.
Published: July 2003

Transcendental dynamic member stiffness matrices for vibration problems arise from solving the governing differential equations to avoid the conventional finite element method (FEM) discretization errors. Assembling them into the overall dynamic structural stiffness matrix gives a transcendental eigenproblem, whose eigenvalues (natural frequencies or their squares) are found with certainty using the Wittrick–Williams algorithm. This paper gives equations for the recently discovered transcendental member stiffness determinant, which equals the appropriately normalized FEM dynamic stiffness matrix determinant of a clamped ended member modelled by infinitely many elements. Multiplying the overall transcendental stiffness matrix determinant by the member stiffness determinants removes its poles to improve curve following eigensolution methods. The present paper gives the first ever derivation of the Bernoulli–Euler member stiffness determinant, which was previously found by trial-and-error and then verified. The derivation uses the total equivalence of the transcendental formulation and an infinite order FEM formulation, which incidentally gives insights into conventional FEM results.
Stochastic Sensitivity of 3D-Elastodynamic Response Subjected to Random Ground Excitation
Authors: Bhattacharyya B. , Chakraborty S.
Published: July 2003

The present study deals with structural sensitivity of dynamic response having uncertainties in design parameters subjected to random earthquake loading. Earthquake is modeled as stationary random process defined by Kanai–Tajimi power spectral density. The uncertain design parameters are modeled as homogeneous Gaussian process and discretized through 3D local averaging. Subsequently the Cholesky decomposition of respective co-variance matrix is used to simulate random values of design parameters. The Neumann expansion blended with Monte Carlo simulation (NE-MCS) is explored for computing response sensitivity in frequency domain. Application examples related to a building frame and a gravity dam are presented serving to validate the NE-MCS technique in terms of its accuracy and effectiveness compared to direct Monte Carlo simulation and perturbation method.
Stiffness Identification by a Substructural Approach in Frequency Domain
Authors: Koh C. G. , Shankar K.
Published: July 2003

The concept of substructure representation is often employed to reduce the size of large and complex models for efficient structural analysis. In the context of structural system identification, this concept has also been used recently to improve numerical accuracy and convergence characteristics. Several research works have thus far demonstrated the effectiveness and advantages of substructural identification. But interface response measurements are usually required as input to the substructure to be identified in these methods. In this paper, a novel substructural method for stiffness identification is proposed with several advantages including eliminating the need of interface response measurement and even force measurement. The identification problem is converted into one of minimizing the difference between measured and predicted displacements at a check point in the substructure. Analytical formulation and numerical study are presented for both lumped mass system and continuous system, taking into consideration the effects of incomplete and noisy data.
Exact Buckling Analysis of Constrained Stepped Columns
Authors: Yang B. , Park D.-H.
Published: July 2003

An analytical technique, called the Effective Stiffness Method (ESM), is developed for static buckling analysis of one-dimensional continua. Based on a distributed transfer function formulation, the ESM delivers exact buckling solutions for constrained stepped columns, eccentrically loaded columns, and columns with initial deflection. The method also obtains highly accurate buckling solutions for columns with arbitrary non-uniform cross-section. The ESM treats different column configurations in a systematic manner, and is numerically efficient. Unlike conventional analytical methods, the proposed method does not use series of continuous functions. The capabilities and advantages of the ESM are demonstrated in numerical examples.