bluuebunny/crossref_metadata_2025 huggingface dataset:
Threshold behaviour and final outcome of an epidemic on a random network with household structure
Authors: Ball Frank , Sirl David , Trapman Pieter
Published: September 2009

In this paper we consider a stochastic SIR (susceptible→infective→removed) epidemic model in which individuals may make infectious contacts in two ways, both within ‘households’ (which for ease of exposition are assumed to have equal size) and along the edges of a random graph describing additional social contacts. Heuristically motivated branching process approximations are described, which lead to a threshold parameter for the model and methods for calculating the probability of a major outbreak, given few initial infectives, and the expected proportion of the population who are ultimately infected by such a major outbreak. These approximate results are shown to be exact as the number of households tends to infinity by proving associated limit theorems. Moreover, simulation studies indicate that these asymptotic results provide good approximations for modestly sized finite populations. The extension to unequal-sized households is discussed briefly.
Exceedance of power barriers for integrated continuous-time stationary ergodic stable processes
Authors: Alparslan Uğur Tuncay
Published: September 2009

We study the asymptotic behavior of the tail probability of integrated stable processes exceeding power barriers. In the first part of the paper the limiting behavior of the integrals of stable processes generated by ergodic dissipative flows is established. In the second part an example with the integral of a stable process generated by a conservative flow is analyzed. Finally, the difference in the order of magnitude of the exceedance probability in the two cases is related to the dependence structure of the underlying stable process.
Generalized fractional kinetic equations: another point of view
Authors: Márquez-Carreras David
Published: September 2009

In this paper we deal with generalized fractional kinetic equations driven by a Gaussian noise, white in time and correlated in space, and where the diffusion operator is the composition of the Bessel and Riesz potentials for any fractional parameters. We give results on the existence and uniqueness of solutions by means of a weak formulation and study the Hölder continuity. Moreover, we prove the existence of a smooth density associated to the solution process and study the asymptotics of this density. Finally, when the diffusion coefficient is constant, we look for its Gaussian index.
Two Rationales Behind the ‘Buy-And-Hold or Sell-At-Once’ Strategy
Authors: Yam S. C. P. , Yung S. P. , Zhou W.
Published: September 2009

The trading strategy of ‘buy-and-hold for superior stock and sell-at-once for inferior stock’, as suggested by conventional wisdom, has long been prevalent in Wall Street. In this paper, two rationales are provided to support this trading strategy from a purely mathematical standpoint. Adopting the standard binomial tree model (or CRR model for short, as first introduced in Cox, Ross and Rubinstein (1979)) to model the stock price dynamics, we look for the optimal stock selling rule(s) so as to maximize (i) the chance that an investor can sell a stock precisely at its ultimate highest price over a fixed investment horizon [0,T]; and (ii) the expected ratio of the selling price of a stock to its ultimate highest price over [0,T]. We show that both problems have exactly the same optimal solution which can literally be interpreted as ‘buy-and-hold or sell-at-once’ depending on the value of p (the going-up probability of the stock price at each step): when p›½, selling the stock at the last time step N is the optimal selling strategy; when p=½, a selling time is optimal if the stock is sold either at the last time step or at the time step when the stock price reaches its running maximum price; and when p‹½, time 0, i.e. selling the stock at once, is the unique optimal selling time.
On the Transition Law of Tempered Stable Ornstein–Uhlenbeck Processes
Authors: Zhang Shibin , Zhang Xinsheng
Published: September 2009

In this paper, a stochastic integral of Ornstein–Uhlenbeck type is represented to be the sum of two independent random variables: one has a tempered stable distribution and the other has a compound Poisson distribution. In distribution, the compound Poisson random variable is equal to the sum of a Poisson-distributed number of positive random variables, which are independent and identically distributed and have a common specified density function. Based on the representation of the stochastic integral, we prove that the transition distribution of the tempered stable Ornstein–Uhlenbeck process is self-decomposable and that the transition density is a C∞-function.
On Approximations of Small Jumps of Subordinators with Particular Emphasis on a Dickman-Type Limit
Authors: Covo Shai
Published: September 2009

Let X be a pure-jump subordinator (i.e. nondecreasing Lévy process with no drift) with infinite Lévy measure, let Xε be the sum of jumps not exceeding ε, and let µ(ε)=E[Xε(1)]. We study the question of weak convergence of Xε/µ(ε) as ε ↓0, in terms of the limit behavior of µ(ε)/ε. The most interesting case reduces to the weak convergence of Xε/ε to a subordinator whose marginals are generalized Dickman distributions; we give some necessary and sufficient conditions for this to hold. For a certain significant class of subordinators for which the latter convergence holds, and whose most prominent representative is the gamma process, we give some detailed analysis regarding the convergence quality (in particular, in the context of approximating X itself). This paper completes, in some respects, the study made by Asmussen and Rosiński (2001).
Convolutions of Long-Tailed and Subexponential Distributions
Authors: Foss Sergey , Korshunov Dmitry , Zachary Stan
Published: September 2009

Convolutions of long-tailed and subexponential distributions play a major role in the analysis of many stochastic systems. We study these convolutions, proving some important new results through a simple and coherent approach, and also showing that the standard properties of such convolutions follow as easy consequences.
Markov Chains Conditioned Never to Wait Too Long at the Origin
Authors: Jacka Saul
Published: September 2009

Motivated by Feller's coin-tossing problem, we consider the problem of conditioning an irreducible Markov chain never to wait too long at 0. Denoting by τ the first time that the chain, X, waits for at least one unit of time at the origin, we consider conditioning the chain on the event (τ›T). We show that there is a weak limit as T→∞ in the cases where either the state space is finite or X is transient. We give sufficient conditions for the existence of a weak limit in other cases and show that we have vague convergence to a defective limit if the time to hit zero has a lighter tail than τ and τ is subexponential.
A Random Multiple-Access Protocol with Spatial Interactions
Authors: Bordenave Charles , Foss Serguei , Shneer Vsevolod
Published: September 2009

We analyse an ALOHA-type random multiple-access protocol where users have local interactions. We show that the fluid model of the system workload satisfies a certain differential equation. We obtain a sufficient condition for the stability of this differential equation and deduce from that a sufficient condition for the stability of the protocol. We discuss the necessary condition. Furthermore, for the underlying Markov chain, we estimate the rate of convergence to the stationary distribution. Then we establish an interesting and unexpected result showing that the main diagonal is locally unstable if the input rate is sufficiently small. Finally, we consider two generalisations of the model.
Duality and Asymptotics for a Class of Nonneutral Discrete Moran Models
Authors: Huillet Thierry , Möhle Martin
Published: September 2009

A Markov chain X with finite state space {0,…,N} and tridiagonal transition matrix is considered, where transitions from i to i-1 occur with probability (i/N)(1-p(i/N)) and transitions from i to i+1 occur with probability (1-i/N)p(i/N). Here p:[0,1]→[0,1] is a given function. It is shown that if p is continuous with p(x)≤p(1) for all x∈[0,1] then, for each N, a dual process Y to X (with respect to a specific duality function) exists if and only if 1-p is completely monotone with p(0)=0. A probabilistic interpretation of Y in terms of an ancestral process of a mixed multitype Moran model with a random number of types is presented. It is shown that, under weak conditions on p, the process Y, properly time and space scaled, converges to an Ornstein–Uhlenbeck process as N tends to ∞. The asymptotics of the stationary distribution of Y is studied as N tends to ∞. Examples are presented involving selection mechanisms. results.
The Logarithmic Skew-Normal Distributions are Moment-Indeterminate
Authors: Lin Gwo Dong , Stoyanov Jordan
Published: September 2009

We study the class oflogarithmic skew-normal (LSN) distributions. They have heavy tails; however, all their moments of positive integer orders are finite. We are interested in the problem of moments for such distributions. We show that the LSN distributions are all nonunique (moment-indeterminate). Moreover, we explicitly describe Stieltjes classes for some LSN distributions; they are families of infinitely many distributions, which are different but have the same moment sequence as a fixed LSN distribution.
H19acts as a trans regulator of the imprinted gene network controlling growth in mice
Authors: Gabory Anne , Ripoche Marie-Anne , Le Digarcher Anne , Watrin Françoise , Ziyyat Ahmed , Forné Thierry , Jammes Hélène , Ainscough Justin F. X. , Surani M. Azim , Journot Laurent , Dandolo Luisa
Published: September 2009

The imprinted H19 gene produces a non-coding RNA of unknown function. Mice lacking H19 show an overgrowth phenotype, due to a cis effect of the H19 locus on the adjacent Igf2 gene. To explore the function of the RNA itself, we produced transgenic mice overexpressing H19. We observed postnatal growth reduction in two independent transgenic lines and detected a decrease of Igf2expression in embryos. An extensive analysis of several other genes from the newly described imprinted gene network (IGN) was performed in both loss- and gain-of-function animals. We found that H19 deletion leads to the upregulation of several genes of the IGN. This overexpression is restored to the wild-type level by transgenic expression of H19. We therefore propose that the H19 gene participates as a trans regulator in the fine-tuning of this IGN in the mouse embryo. This is the first in vivo evidence of a functional role for the H19 RNA. Our results also bring further experimental evidence for the existence of the IGN and open new perspectives in the comprehension of the role of genomic imprinting in embryonic growth and in human imprinting pathologies.
Lineage-specific cell death in postembryonic brain development ofDrosophila
Authors: Kumar Abhilasha , Bello Bruno , Reichert Heinrich
Published: September 2009

The Drosophila central brain is composed of thousands of neurons that derive from approximately 100 neuroblasts per hemisphere. Functional circuits in the brain require precise neuronal wiring and tight control of neuronal numbers. How this accurate control of neuronal numbers is achieved during neural development is largely unclear. Specifically, the role of programmed cell death in control of cell numbers has not been studied in the central brain neuroblast lineages. Here, we focus on four postembryonic neuroblast lineages in the central brain identified on the basis that they express the homeobox gene engrailed (en). For each lineage,we determine the total number of adult-specific neurons generated as well as number and pattern of en-expressing cells. We then demonstrate that programmed cell death has a pronounced effect on the number of cells in the four lineages; approximately half of the immature adult-specific neurons in three of the four lineages are eliminated by cell death during postembryonic development. Moreover, we show that programmed cell death selectively affects en-positive versus en-negative cells in a lineage-specific manner and, thus, controls the relative number of en-expressing neurons in each lineage. Furthermore, we provide evidence that Notch signaling is involved in the regulation of en expression. Based on our findings, we conclude that lineage-specific programmed cell death plays a prominent role in the generation of neuronal number and lineage diversity in the Drosophila brain.
A gene network for long-day flowering activatesRFT1encoding a mobile flowering signal in rice
Authors: Komiya Reina , Yokoi Shuji , Shimamoto Ko
Published: September 2009

Although some genes that encode sensory or regulatory elements for photoperiodic flowering are conserved between the long-day (LD) plant Arabidopsis thaliana and the short-day (SD) plant rice, the gene networks that control rice flowering, and particularly flowering under LD conditions, are not well understood. We show here that RICE FLOWERING LOCUS T 1 (RFT1), the closest homolog to Heading date 3a (Hd3a), is a major floral activator under LD conditions. An RFT1:GFP fusion protein localized in the shoot apical meristem (SAM) under LD conditions, suggesting that RFT1 is a florigen gene in rice. Furthermore, mutants in OsMADS50, a rice ortholog of Arabidopsis SUPPRESOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) did not flower up to 300 days after sowing under LD conditions, indicating that OsMADS50, which acts upstream of RFT1, promotes flowering under LD conditions. We propose that both positive (OsMADS50 and Ehd1) and negative (Hd1, phyB and Ghd7) regulators of RFT1 form a gene network that regulates LD flowering in rice. Among these regulators, Ehd1, a rice-specific floral inducer,integrates multiple pathways to regulate RFT1, leading to flowering under appropriate photoperiod conditions. A rice ortholog of Arabidopsis APETALA1, OsMADS14, was expressed in the floral meristem in wild-type but not in RFT1 RNAi plants, suggesting that OsMADS14 is activated by RFT1 protein in the SAM after the transition to flowering. We have thus exposed a network of genes that regulate LD flowering in rice.
Convergent extension movements in growth plate chondrocytes require gpi-anchored cell surface proteins
Authors: Ahrens Molly J. , Li Yuwei , Jiang Hongmei , Dudley Andrew T.
Published: September 2009

Proteins that are localized to the cell surface via glycosylphosphatidylinositol (gpi) anchors have been proposed to regulate cell signaling and cell adhesion events involved in tissue patterning. Conditional deletion of Piga, which encodes the catalytic subunit of an essential enzyme in the gpi-biosynthetic pathway, in the lateral plate mesoderm results in normally patterned limbs that display chondrodysplasia. Analysis of mutant and mosaic Piga cartilage revealed two independent cell autonomous defects. First, loss of Piga function interferes with signal reception by chondrocytes as evidenced by delayed maturation. Second, the proliferative chondrocytes, although present, fail to flatten and arrange into columns. We present evidence that the abnormal organization of mutant proliferative chondrocytes results from errors in cell intercalation. Collectively, our data suggest that the distinct morphological features of the proliferative chondrocytes result from a convergent extension-like process that is regulated independently of chondrocyte maturation.
Spindle alignment is achieved without rotation after the first cell cycle inDrosophilaembryonic neuroblasts
Authors: Rebollo Elena , Roldán Mónica , Gonzalez Cayetano
Published: September 2009

Spindle alignment along the apicobasal polarity axis is mandatory for proper self-renewing asymmetric division in Drosophila neuroblasts(NBs). In embryonic NBs, spindles have been reported to assemble orthogonally to the polarity axis and later rotate to align with it. In larval NBs,spindles assemble directly aligned with the axis owing to the differential spatiotemporal control of the microtubule organising activity of their centrosomes. We have recorded embryonic NBs that express centrosome and microtubule reporters, from delamination up to the fourth cell cycle, by two-photon confocal microscopy, and have found that the switch between these two spindle orientation modes occurs in the second cell cycle of the NB, the first that follows delamination. Therefore, predetermined spindle orientation is not restricted to larval NBs. On the contrary, it actually applies to all but the first cell cycle of embryonic NBs.
Treatment of incompetent perforating veins using the radiofrequency ablation stylet: a pilot study
Authors: van den Bos R R , Wentel T , Neumann M H A , Nijsten T
Published: September 2009

Background

Although the role of incompetent perforating veins (IPV) in chronic venous insufficiency remains controversial, they are often treated by surgical or by minimal invasive techniques.

Objectives

To describe the procedure of radiofrequency ablation (RFA) of IPV and to evaluate its short-term effectiveness and safety.

Methods

In a clinical pilot study, 14 IPV in 12 patients were treated with a radiofrequency stylet. After three months, ultrasound (US) examination was used to assess anatomical success rate and exclude deep venous thrombosis. Also, self-reported side-effects were investigated.

Results

Of the 14 treated IPV, nine (64%) were obliterated on US examination and the others showed remaining reflux. Two patients reported localized paresthesia, but no deep venous thrombosis was recorded.

Conclusion

RFA of IPV may be a promising procedure, but patient and incompetent perforator vein selection is important and further standardization of the procedure is required. Comparative clinical trials between RFA and other therapies are warranted.
Arterio-venous malformation: how much do we know?
Authors: Lee B B , Lardeo J , Neville R
Published: September 2009

Arterio-venous malformation (AVM) is a congenital vascular malformation that is neither a venous malformation nor a haemangioma. An AVM is a potentially life-threatening and limb-threatening lesion, especially the ‘fistulous’ truncular form due to its unique embryological and haemodynamic characteristics. AVM treatment requires an early aggressive approach, one that is careful and based on a thorough assessment of the risks and benefits associated with the treatment plan.

A successful treatment strategy requires an accurate assessment of the AVM taking into account the extent, severity and progression of the lesion. This is critical in order to minimize the morbidity associated with the currently available therapies. A multidisiciplinary approach that integrates endovascular and surgical therapy can substantially improve the treatment results seen in patients with AVMs. Preliminary treatment of a fistulous AVM with coil embolization is essential in order to minimize associated morbidity and to alter the lesion haemodynamics from a high-flow lesion to a low-flow lesion that is more amenable to subsequent, definitive management with ethanol or NBCA glue embolo/sclerotherapy.
A Lagrangean Heuristic for Hub-and-Spoke System Design with Capacity Selection and Congestion
Authors: Elhedhli Samir , Wu Huyu
Published: September 2009

Hub-and-spoke networks are widely applied in a variety of industries such as transportation, postal delivery, and telecommunications. Although they are designed to exploit economies of scale, hub-and-spoke networks are known to favour congestion, jeopardizing the performance of the entire system. This paper looks at incorporating congestion and capacity decisions in the design stage of such networks. The problem is formulated as a nonlinear mixed-integer program (NMIP) that explicitly minimizes congestion, capacity acquisition, and transportation costs. Congestion at hubs is modeled as the ratio of total flow to surplus capacity by viewing the hub-and-spoke system as a network of M/M/1 queues. To solve the NMIP, we propose a Lagrangean heuristic where the problem is decomposed into an easy subproblem and a more difficult nonlinear subproblem. The nonlinear subproblem is first linearized using piecewise functions and then solved to optimality using a cutting plane method. The Lagrangean lower bound is found using subgradient optimization. The solution from the subproblems is used to find a heuristic solution. Computational results indicate the efficiency of the methodology in providing a sharp bound and in generating high-quality feasible solutions in most cases.
Elastic-Plastic Stress Analysis of Cold-Worked Pin-Loaded Holes
Authors: Ismonov S. , Daniewicz S. R. , Newman J. C.
Published: September 2009

A detailed two-dimensional, elastic-plastic finite element analysis of a pin-loaded hole was conducted. A thin rectangular aluminum alloy sheet (7075-T6) with a circular hole was considered under plane stress conditions. The hole was loaded purely by a rigid pin to different load magnitudes. Appropriate contact elements were used at the pin-hole interface to transfer the traction loads from one surface to another. Material nonlinearities for the sheet and friction were included in the analyses. Radial and hoop stress solutions along the pin-hole interface were compared in elastically and plastically loaded holes. The influence of friction on the stress results was studied. The locations and magnitudes of the peak hoop stresses were determined. Lastly, an initial residual field was introduced around the hole by a cold expansion simulation before a subsequent pin-loading analysis. Because the cold expansion process involves some reverse yielding, both isotropic and kinematic material hardening models were considered.
Keynote—Materials Selection for Oxidizer Service—Successes and Challenges
Authors: Slusser Joseph W.
Published: September 2009

Improper selection of materials of construction for oxygen and other strong oxidizer applications can result in sudden catastrophic failure. Many available materials are flammable and will burn in oxidizer systems if sufficient ignition energy is provided. Because these combustion events occur suddenly, they cannot be monitored by periodic inspection. Also, a definitive cause after such an event is often difficult to determine because much of the evidence is destroyed. Materials selection and system design must be correct from the beginning. The key is to ensure the ignition energies imposed on the materials during operation of the system do not challenge the materials. Or, to state it differently, a designer must ensure that the materials selected have adequate compatibility to withstand the operating conditions (including transient conditions such as startups) without igniting. This paper will provide an overview of the science of oxygen compatibility and how Committee G04 efforts have helped improve safety. It will also comment on the technical issues the Committee may address in the future and a concern, shared with many similar organizations, of declining industry participation.
Connected Kids at Head Start: Taking Office-Based Violence Prevention to the Community
Authors: Cowden John D. , Smith Shayna , Pyle Sarah , Dowd M. Denise
Published: September 2009

OBJECTIVE: The goal was to assess the acceptability and appropriateness of using a violence prevention curriculum, Connected Kids: Safe, Strong, Secure, at Head Start centers.

METHODS: Eight 90-minute focus groups (4 parent groups and 4 family advocate groups) were conducted at 2 Head Start centers. Each discussion was audiotaped, transcribed, and analyzed for major themes.

RESULTS: A total of 63 adults (38 family advocates [92% female] and 25 parents [100% female]) participated in the 8 groups. Family advocates and parents agreed that Head Start was an important source of parenting advice and of referrals to community resources. Connected Kids topics were well received, although potential parental resistance to gun safety and discipline materials was identified. The positive nature of the advice was important to both types of groups. Brochures were generally well liked, but all groups thought that they should be linked directly to community resource information and offered as part of tailored education. Various venues for curriculum use were suggested, and formats involving multiple media were requested. Although Head Start serves preschool-aged children, parents and family advocates valued access to the full range of Connected Kids materials (for ages 0–18 years). Family advocates emphasized that supplementary materials on background information and delivery methods would be essential for effective implementation of Connected Kids at Head Start.

CONCLUSIONS: Head Start family advocates and parents found the Connected Kids curriculum desirable. Although modifications might improve its usefulness, the curriculum seems acceptable and appropriate for the Head Start environment.
Chemical beam deposition of high-k gate dielectrics on III-V semiconductors: TiO2 on In0.53Ga0.47As
Authors: Engel-Herbert Roman , Hwang Yoontae , LeBeau James , Zheng Yan , Stemmer Susanne
Published: September 2009

We report on the growth of high-permittivity (k) TiO2 thin films on In0.53Ga0.47As channels by chemical beam deposition with titanium isopropoxide as the source. The films grew in a reaction-limited regime with smooth surfaces. High-resolution transmission electron microscopy showed an atomically abrupt interface with the In0.53Ga0.47As channel that indicated that this interface is thermally stable. Measurements of the leakage currents using metal-oxide-semiconductor capacitors with Pt top electrodes revealed asymmetric characteristics with respect to the bias polarity, suggesting an unfavorable band alignment for CMOS applications. X-ray photoelectron spectroscopy was used to determine the TiO2/In0.53Ga0.47As band offsets. A valence band offset of 2.5 ± 0.1 eV was measured.
The Sociolinguisic Creation of Opposing Representations of Defendants and Victims
Authors: Felton Rosulek Laura
Published: September 2009

This paper presents a critical analysis of the terms of reference lawyers employ in the closing arguments in criminal trials to create competing representations of the same social actors. Through a systematic discourse analysis of ten closing arguments, I show that the prosecution's and defense's differing goals cause them to strategically depict the same defendants, victims, and witnesses in diametrically different manners. Actors who are contrary to an argument are backgrounded or silenced. The two key theoretical constructs then employed by lawyers are personalization and functionalization (van Leeuwen 2002). For example, the defendants, while personalized by the defense, are functionalized by the prosecution, in effect erasing their unique identity except for their role as their person on trial. In sum, I show that through the use of these subtle linguistic tools, lawyers for opposing sides create contrasting representations of the same individuals so that they serve the lawyers' goals.
The DyViS database: style-controlled recordings of 100 homogeneous speakers for forensic phonetic research
Authors: Nolan Francis , McDougall Kirsty , de Jong Gea , Hudson Toby
Published: September 2009

The DyViS project (‘Dynamic Variability in Speech: a Forensic Phonetic Study of British English’) at the University of Cambridge has compiled a large-scale database of speech recordings which will be freely available for (non-commercial) research purposes. The database comprises recordings of 100 male speakers of Standard Southern British English, aged 18-25, undertaking four tasks involving different speaking styles: a simulated police interview, a telephone call with an ‘accomplice’, a reading passage, and a set of read sentences. This paper describes the motivation for developing the DyViS database and explains its structure, including the novel techniques developed for eliciting spontaneous yet phonetically controlled speech under simulated forensic conditions.
The Law on Language in the European Union: Policy Development for Interpreting/Translation Services in Criminal Proceedings
Authors: Schweda Nicholson Nancy
Published: September 2009

Membership in the European Union (EU) has grown to 27 Member States. As an arm of the Commission of the European Communities, the Directorate General: Justice, Security and Freedom is charged with setting common EU legal standards and promoting consistent compliance among all Member States. The current article examines a Proposal for a Council Framework Decision (PCFD) on Certain Procedural Rights in Criminal Proceedings. A major focus of the PCFD is the provision of language services (interpreting and translation) for individuals who do not speak the language of the court/legal system in which they find themselves. This paper traces the progress of the PCFD from its introduction in 2004 to its demise in 2007. Related topics of discussion include the European Convention on Human Rights, the Treaty of Lisbon, and additional relevant developments in the language services area. The article concludes with a look at potential future legislation.
Exploring the Discriminatory Potential of F0 Distribution Parameters in Traditional Forensic Speaker Recognition
Authors: Kinoshita Yuko , Ishihara Shunichi , Rose Philip
Published: September 2009

Despite its many prima facie attractive properties for Forensic Speaker Recognition, F0 is regarded as having limited forensic value due to its large within-speaker variability. However, its forensic use to date has been limited mostly to its long-term mean and standard deviation. This paper examines the discriminatory potential, within a Likelihood Ratio-based approach, of additional parametric features from the distribution of long-term F0: its skew, kurtosis, modal F0 and modal density. Motivated by the observation that the shape of the long-term F0 distribution shows less within-speaker occasion-to-occasion difference, we report a forensic discrimination experiment with non-contemporaneous speech samples from 201 male Japanese speakers. Using a multivariate Likelihood Ratio as discriminant distance with the six LTF0 distribution parameters, an equal error rate of 10.7% is obtained from 201 target and 80400 non-target trials. We also investigate how the EER degrades as a function of amount of voiced speech.
Universal Intervention as a Protective Shield Against Exposure to Substance Use: Long-Term Outcomes and Public Health Significance
Authors: Spoth Richard , Guyll Max , Shin Chungyeol
Published: September 2009

Objectives. We examined universal preventive intervention effects on adolescents' exposure to opportunities for substance use and on illicit substance use in the long term.

Methods. Public schools (N = 22) were randomly assigned to the Iowa Strengthening Families Program (ISFP) or a control condition. We used odds ratio (OR) calculations and structural modeling to test the effects of the ISFP in the 6th grade on exposure to substance use across adolescence, as well as on 12th-grade illicit substance use occurring via reductions in exposure.

Results. The ISFP was associated with reduced exposure to illicit substance use (1.25 ≤ OR ≤ 2.37) that was, in turn, associated with reduced 12th-grade substance use (2.87 ≤ OR ≤ 6.35). The ISFP also reduced the rate of increase in exposure across adolescence (B = −0.37; P < .001), which was associated with the likelihood of 12th-grade illicit substance use (B = 0.30; P = .021), with a significant indirect effect (B = −0.11; P = .048).

Conclusions. The ISFP in the 6th grade reduced substance use through a “protective shield” of reduced exposure. The relative reduction rate was 49%, which suggests that universal prevention shields can contribute to significant reductions in illicit substance use among adolescents.
Investigating the Link Between Gun Possession and Gun Assault
Authors: Branas Charles C. , Richmond Therese S. , Culhane Dennis P. , Ten Have Thomas R. , Wiebe Douglas J.
Published: September 2009

Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time.

Methods. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables.

Results. After adjustment, individuals in possession of a gun were 4.46 (P < .05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P < .05).

Conclusions. On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.
Social-Environmental Factors and Protective Sexual Behavior Among Sex Workers: The Encontros Intervention in Brazil
Authors: Lippman Sheri A. , Donini Angela , Díaz Juan , Chinaglia Magda , Reingold Arthur , Kerrigan Deanna
Published: September 2009

Objectives. We sought to determine the association of social–environmental factors with condom use and sexually transmitted infections (STIs) among 420 sex workers participating in an STI/HIV prevention study in Corumbá, Brazil, to inform future intervention efforts.

Methods. Participants provided urine samples for polymerase chain reaction testing of chlamydia and gonorrhea and responded to multi-item scales addressing perceived social cohesion, participation in networks, and access to and management of resources. We conducted multivariate log-linear and negative binomial regression analyses of these data.

Results. Increased social cohesion was inversely associated with number of unprotected sex acts in the preceding week among women (adjusted incidence rate ratio [IRR] = 0.80; P < .01), and there was a marginal association among men (adjusted IRR = 0.41; P = .08). Women's increased participation in social networks was associated with a decrease in frequency of unprotected sex acts (adjusted IRR = 0.83; P = .04), as was men's access to and management of social and material resources (IRR = 0.15; P = .01). Social–environmental factors were not associated with STIs.

Conclusions. The social context within which populations negotiate sexual behaviors is associated with condom use. Future efforts to prevent STI/HIV should incorporate strategies to modify the social environment.
Stroke Mortality Among Alaska Native People
Authors: Horner Ronnie D. , Day Gretchen M. , Lanier Anne P. , Provost Ellen M. , Hamel Rebecca D. , Trimble Brian A.
Published: September 2009

Objectives. We aimed to describe the epidemiology of stroke among Alaska Natives, which is essential for designing effective stroke prevention and intervention efforts for this population.

Methods. We conducted an analysis of death certificate data for the state of Alaska for the period 1984 to 2003, comparing age-standardized stroke mortality rates among Alaska Natives residing in Alaska vs US Whites by age category, gender, stroke type, and time.

Results. Compared with US Whites, Alaska Natives had significantly elevated stroke mortality from 1994 to 2003 but not from 1984 to 1993. Alaska Native women of all age groups and Alaska Native men younger than 45 years of age had the highest risk, although the rates for those younger than 65 years were statistically imprecise. Over the 20-year study period, the stroke mortality rate was stable for Alaska Natives but declined for US Whites.

Conclusions. Stroke mortality is higher among Alaska Natives, especially women, than among US Whites. Over the past 20 years, there has not been a significant decline in stroke mortality among Alaska Natives.
STD Prevalence, Risky Sexual Behaviors, and Sex With Women in a National Sample of Chinese Men Who Have Sex With Men
Authors: Wei Chongyi , Guadamuz Thomas E. , Stall Ron , Wong Frank Y.
Published: September 2009

We describe the behavioral characteristics and sexually transmitted disease (STD) prevalence of Chinese men who have sex with men (MSM) (n = 41) from a national probability sample of men (n = 1861). Most MSM were partnered with females (97%) and had a low rate of consistent condom use (7%). More MSM than heterosexual men self-reported a prior STD and risky sexual behaviors. MSM may act as a bridge for HIV transmission to female partners. Targeted interventions may help prevent a generalized HIV epidemic in China.
The Sonoma Water Evaluation Trial: A Randomized Drinking Water Intervention Trial to Reduce Gastrointestinal Illness in Older Adults
Authors: Colford John M. , Hilton Joan F. , Wright Catherine C. , Arnold Benjamin F. , Saha Sona , Wade Timothy J. , Scott James , Eisenberg Joseph N.S.
Published: September 2009

Objectives. We estimated the relative rate of highly credible gastrointestinal illness (HCGI) per year associated with active versus sham household water filtration devices among older adults in a community receiving tap water meeting current US standards.

Methods. We conducted a randomized, triple-blinded, crossover trial in 714 households (988 individuals), which used active and sham water filtration devices for 6 months each. We estimated the annual incidence rate ratio of HCGI episodes and the longitudinal prevalence ratio of HCGI days at population and individual levels with a generalized estimating equation (GEE) and generalized linear mixed models (GLMMs), respectively, adjusted for covariates associated with outcome.

Results. The incidence rate ratios (active versus sham) were 0.88 (95% confidence interval [CI] = 0.77, 1.00) and 0.85 (95% CI = 0.76, 0.94) HCGI episodes per year estimated by GEE and GLMM models, respectively. The corresponding longitudinal prevalence ratios were 0.88 (95% CI = 0.74, 1.05) and 0.84 (95% CI = 0.78, 0.90) HCGI days per person per year.

Conclusions. We observed reductions in population- and individual-level measures of HCGI associated with use of the active filtration device. These findings suggest the need for further research on the impact of drinking water on the health of sensitive subpopulations.
Medication Prescribing Practices for Older Prisoners in the Texas Prison System
Authors: Williams Brie A. , Baillargeon Jacques G. , Lindquist Karla , Walter Louise C. , Covinsky Kenneth E. , Whitson Heather E. , Steinman Michael A.
Published: September 2009

Objectives. We sought to assess appropriateness of medication prescribing for older Texas prisoners.

Methods. In this 12-month cross-sectional study of 13 117 prisoners (aged ≥ 55 years), we assessed medication use with Zhan criteria and compared our results to prior studies of community prescribing. We assessed use of indicated medications with 6 Assessing Care of Vulnerable Elders indicators.

Results. Inappropriate medications were prescribed to a third of older prisoners; half of inappropriate use was attributable to over-the-counter antihistamines. When these antihistamines were excluded, inappropriate use dropped to 14% (≥ 55 years) and 17% (≥ 65 years), equivalent to rates in a Department of Veterans Affairs study (17%) and lower than rates in a health maintenance organization study (26%). Median rate of indicated medication use for the 6 indicators was 80% (range = 12%–95%); gastrointestinal prophylaxis for patients on nonsteroidal anti-inflammatories at high risk for gastrointestinal bleed constituted the lowest rate.

Conclusions. Medication prescribing for older prisoners in Texas was similar to that for older community adults. However, overuse of antihistamines and underuse of gastrointestinal prophylaxis suggests a need for education of prison health care providers in appropriate prescribing practices for older adults.
Changes Not for the Fainthearted: Reorienting Health Care Systems Toward Health Equity Through Action on the Social Determinants of Health
Authors: Baum Fran E. , Bégin Monique , Houweling Tanja A. J. , Taylor Sebastian
Published: September 2009

Entrenched poor health and health inequity are important public health problems. Conventionally, solutions to such problems originate from the health care sector, a conception reinforced by the dominant biomedical imagination of health. By contrast, attention to the social determinants of health has recently been given new force in the fight against health inequity. The health care sector is a vital determinant of health in itself and a key resource in improving health in an equitable manner. Actors in the health care sector must recognize and reverse the sector's propensity to generate health inequity. The sector must also strengthen its role in working with other sectors of government to act collectively on the deep-rooted causes of poor and inequitable health.
Association Between Widowhood and Risk of Diagnosis With a Sexually Transmitted Infection in Older Adults
Authors: Smith Kirsten P. , Christakis Nicholas A.
Published: September 2009

Objectives. We assessed whether widowhood is associated with risk of diagnosis with a sexually transmitted infection (STI) among older adults in the United States and whether the associations observed in men differed before and after the introduction of sildenafil, the first oral erectile dysfunction medication approved by the Food and Drug Administration.

Methods. We used Cox proportional hazards regression to analyze the time to first STI diagnosis in a random sample of married, Medicare-eligible couples aged 67 to 99 years in 1993 (N = 420 790 couples).

Results. Twenty-one percent of male and 43% of female participants lost a spouse during the 9-year study period. Only 0.65% of men and 0.97% of women were diagnosed with an STI. Widowhood was associated with an increased risk of STI diagnosis for men only, with the largest effects found 0.5 to 1 year after a wife's death. Effects for men were larger after the introduction of sildenafil.

Conclusions. Widowhood in older men, but not women, increased the risk for STIs, especially in the postsildenafil era. Clinicians should address sexual health issues with older patients, especially bereaved men taking erectile dysfunction medications.
Childhood Socioeconomic Position and Disability in Later Life: Results of the Health and Retirement Study
Authors: Bowen Mary Elizabeth , González Hector M.
Published: September 2009

Objectives. We used a life course approach to assess the ways in which childhood socioeconomic position may be associated with disability in later life.

Methods. We used longitudinal data from the nationally representative Health and Retirement Study (1998–2006) to examine associations between parental education, paternal occupation, and disabilities relating to activities of daily living (ADLs) and instrumental activities of daily living (IADLs).

Results. Respondents whose fathers had low levels of education and those whose fathers were absent or had died while they were growing up were at increased risk of disability in later life, net of social, behavioral, and pathological health risks in adulthood. Social mobility and health behaviors were also important factors in the association between low childhood socioeconomic position and ADL and IADL disabilities.

Conclusions. Our findings highlight the need for policies and programs aimed at improving the well-being of both children and families. A renewed commitment to such initiatives may help reduce health care costs and the need for people to use health and social services in later life.
Implementing Evidence-Based Practice in Community Mental Health Agencies: A Multiple Stakeholder Analysis
Authors: Aarons Gregory A. , Wells Rebecca S. , Zagursky Karen , Fettes Danielle L. , Palinkas Lawrence A.
Published: September 2009

Objectives. We sought to identify factors believed to facilitate or hinder evidence-based practice (EBP) implementation in public mental health service systems as a step in developing theory to be tested in future studies.

Methods. Focusing across levels of an entire large public sector mental health service system for youths, we engaged participants from 6 stakeholder groups: county officials, agency directors, program managers, clinical staff, administrative staff, and consumers.

Results. Participants generated 105 unique statements identifying implementation barriers and facilitators. Participants rated each statement on importance and changeability (i.e., the degree to which each barrier or facilitator is considered changeable). Data analyses distilled statements into 14 factors or dimensions. Descriptive analyses suggest that perceptions of importance and changeability varied across stakeholder groups.

Conclusions. Implementation of EBP is a complex process. Cross-system–level approaches are needed to bring divergent and convergent perspectives to light. Examples include agency and program directors facilitating EBP implementation by supporting staff, actively sharing information with policymakers and administrators about EBP effectiveness and fit with clients' needs and preferences, and helping clinicians to present and deliver EBPs and address consumer concerns.
Eliminating Health Disparities Through Transdisciplinary Research, Cross-Agency Collaboration, and Public Participation
Authors: Rashid Jamila R. , Spengler Robert F. , Wagner Robin M. , Melanson Cindi , Skillen Elizabeth L. , Mays Robert A. , Heurtin-Roberts Suzanne , Long Judith A.
Published: September 2009

Despite efforts to the contrary, disparities in health and health care persist in the United States. To solve this problem, federal agencies representing different disciplines and perspectives are collaborating on a variety of transdisciplinary research initiatives. The most recent of these initiatives was launched in 2006 when the Centers for Disease Control and Prevention's Office of Public Health Research and the Department of Health and Human Services’ Office of Minority Health brought together federal partners representing a variety of disciplines to form the Federal Collaboration on Health Disparities Research (FCHDR).

FCHDR collaborates with a wide variety of federal and nonfederal partners to support and disseminate research that aims to reduce or eliminate disparities in health and health care. Given the complexity involved in eliminating health disparities, there is a need for more transdisciplinary, collaborative research, and facilitating that research is FCHDR's mission.
The Benefits of Risk Factor Prevention in Americans Aged 51 Years and Older
Authors: Goldman Dana P. , Zheng Yuhui , Girosi Federico , Michaud Pierre-Carl , Olshansky S. Jay , Cutler David , Rowe John W.
Published: September 2009

Objectives. We assessed the potential health and economic benefits of reducing common risk factors in older Americans.

Methods. A dynamic simulation model tracked a national cohort of persons 51 and 52 years of age to project their health and medical spending in prevention scenarios for diabetes, hypertension, obesity, and smoking.

Results. The gain in life span from successful treatment of a person aged 51 or 52 years for obesity would be 0.85 years; for hypertension, 2.05 years; and for diabetes, 3.17 years. A 51- or 52-year-old person who quit smoking would gain 3.44 years. Despite living longer, those successfully treated for obesity, hypertension, or diabetes would have lower lifetime medical spending, exclusive of prevention costs. Smoking cessation would lead to increased lifetime spending. We used traditional valuations for a life-year to calculate that successful treatments would be worth, per capita, $198 018 (diabetes), $137 964 (hypertension), $118 946 (smoking), and $51 750 (obesity).

Conclusions. Effective prevention could substantially improve the health of older Americans, and—despite increases in longevity—such benefits could be achieved with little or no additional lifetime medical spending.