Concave Switching in Single and Multihop Networks

Switched queueing networks model wireless networks, input queued switches and numerous other networked communications systems. For single-hop networks, we consider a {($\alpha,g$)-switch policy} which combines the MaxWeight policies with bandwidth sharing networks -- a further well studied model of Internet congestion. We prove the maximum stability property for this class of randomized policies. Thus these policies have the same first order behavior as the MaxWeight policies. However, for multihop networks some of these generalized polices address a number of critical weakness of the MaxWeight/BackPressure policies. For multihop networks with fixed routing, we consider the Proportional Scheduler (or (1,log)-policy). In this setting, the BackPressure policy is maximum stable, but must maintain a queue for every route-destination, which typically grows rapidly with a network's size. However, this proportionally fair policy only needs to maintain a queue for each outgoing link, which is typically bounded in number. As is common with Internet routing, by maintaining per-link queueing each node only needs to know the next hop for each packet and not its entire route. Further, in contrast to BackPressure, the Proportional Scheduler does not compare downstream queue lengths to determine weights, only local link information is required. This leads to greater potential for decomposed implementations of the policy. Through a reduction argument and an entropy argument, we demonstrate that, whilst maintaining substantially less queueing overhead, the Proportional Scheduler achieves maximum throughput stability.Comment: 28 page

Sediment budget possibilities and improbabilities

Problems of constructing a sediment budget for an inlet is often a challenge due to constraints on data collection, quality of data, and assumptions one is willing to consider. Existing literature does not provide a systematic foundation for equations considered and often engineers and geologists typically do not properly consider the mathematical constraints placed on the problem of sediment budget construction. The present technical note presents a simple methodology for assessing sediment budget, i.e. what is possible, and what is not possible via a matrix equation system and linear algebra. It is hoped that engineers and geologists will not impose unrealistic expectations on the sediment budget system via using such an approach. Some simple examples are given of both pitfalls and correct approaches to sediment budget development

Machine direction registration dynamics model of a rotary printing press

We derive an analytical model of the machine direction registration dynamics of a continuous-web, electronic line shaft (ELS) rotary printing press. We use the model to quantify the affect of tension disturbances on machine direction registration dynamics with different control schemes. With standard ELS registration control schemes, we show the benefits of using a compensator roller vs. electronic differential gear (advance or retard print cylinder's angular position). Next, we develop a novel cascaded reference control scheme for an electronic differential gear controlled ELS printing press that allows it to rival the performance of a compensator roller controlled ELS printing press. Finally, we demonstrate the benefits of using a cascaded reference empirically on a 6-station rotogravure ELS printing press

KIR content genotypes associate with carriage of hepatitis B surface antigen, e antigen and HBV viral load in Gambians.

BACKGROUND: Hepatocellular carcinoma (HCC) causes over 800,000 deaths worldwide annually, mainly in low income countries, and incidence is rising rapidly in the developed world with the spread of hepatitis B (HBV) and C (HCV) viruses. Natural Killer (NK) cells protect against viral infections and tumours by killing abnormal cells recognised by Killer-cell Immunoglobulin-like Receptors (KIR). Thus genes and haplotypes encoding these receptors may be important in determining both outcome of initial hepatitis infection and subsequent chronic liver disease and tumour formation. HBV is highly prevalent in The Gambia and the commonest cause of liver disease. The Gambia Liver Cancer Study was a matched case-control study conducted between September 1997 and January 2001 where cases with liver disease were identified in three tertiary referral hospitals and matched with out-patient controls with no clinical evidence of liver disease. METHODS: We typed 15 KIR genes using the polymerase chain reaction with sequence specific primers (PCR-SSP) in 279 adult Gambians, 136 with liver disease (HCC or Cirrhosis) and 143 matched controls. We investigated effects of KIR genotypes and haplotypes on HBV infection and associations with cirrhosis and HCC. RESULTS: Homozygosity for KIR group A gene-content haplotype was associated with HBsAg carriage (OR 3.7, 95% CI 1.4-10.0) whilst telomeric A genotype (t-AA) was associated with reduced risk of e antigenaemia (OR 0.2, 95% CI 0.0-0.6) and lower viral loads (mean log viral load 5.2 vs. 6.9, pc = 0.022). One novel telomeric B genotype (t-ABx2) containing KIR3DS1 (which is rare in West Africa) was also linked to e antigenaemia (OR 8.8, 95% CI 1.3-60.5). There were no associations with cirrhosis or HCC. CONCLUSION: Certain KIR profiles may promote clearance of hepatitis B surface antigen whilst others predispose to e antigen carriage and high viral load. Larger studies are necessary to quantify the effects of individual KIR genes, haplotypes and KIR/HLA combinations on long-term viral carriage and risk of liver cancer. KIR status could potentially inform antiviral therapy and identify those at increased risk of complications for enhanced surveillance

Identification of BPIFA1/SPLUNC1 as an epithelium-derived smooth muscle relaxing factor

Asthma is a chronic airway disease characterized by inflammation, mucus hypersecretion and abnormal airway smooth muscle (ASM) contraction. Bacterial permeability family member A1, BPIFA1, is a secreted innate defence protein. Here we show that BPIFA1 levels are reduced in sputum samples from asthmatic patients and that BPIFA1 is secreted basolaterally from healthy, but not asthmatic human bronchial epithelial cultures (HBECs), where it suppresses ASM contractility by binding to and inhibiting the Ca2+ influx channel Orai1. We have localized this effect to a specific, C-terminal α-helical region of BPIFA1. Furthermore, tracheas from Bpifa1−/− mice are hypercontractile, and this phenotype is reversed by the addition of recombinant BPIFA1. Our data suggest that BPIFA1 deficiency in asthmatic airways promotes Orai1 hyperactivity, increased ASM contraction and airway hyperresponsiveness. Strategies that target Orai1 or the BPIFA1 deficiency in asthma may lead to novel therapies to treat this disease

A randomized controlled trial testing the efficacy of a brief cannabis universal prevention program among adolescents in primary care

Aims To examine the efficacy of a brief intervention delivered by a therapist ( TBI ) or a computer ( CBI ) in preventing cannabis use among adolescents in urban primary care clinics. Design A randomized controlled trial comparing: CBI and TBI versus control. Setting Urban primary care clinics in the U nited S tates. Participants Research staff recruited 714 adolescents (aged 12–18 years) who reported no life‐time cannabis use on a screening survey for this study, which included a baseline survey, randomization (stratified by gender and grade) to conditions (control; CBI ; TBI ) and 3‐, 6‐ and 12‐month assessments. Measurements Using an intent‐to‐treat approach, primary outcomes were cannabis use (any, frequency); secondary outcomes included frequency of other drug use, severity of alcohol use and frequency of delinquency (among 85% completing follow‐ups). Findings Compared with controls, CBI participants had significantly lower rates of any cannabis use over 12 months (24.16%, 16.82%, respectively, P  < 0.05), frequency of cannabis use at 3 and 6 months ( P  < 0.05) and other drug use at 3 months ( P  < 0.01). Compared with controls, TBI participants did not differ in cannabis use or frequency, but had significantly less other drug use at 3 months ( P  < 0.05), alcohol use at 6 months ( P  < 0.01) and delinquency at 3 months ( P  < 0.01). Conclusions Among adolescents in urban primary care in the U nited S tates, a computer brief intervention appeared to prevent and reduce cannabis use. Both computer and therapist delivered brief interventions appeared to have small effects in reducing other risk behaviors, but these dissipated over time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106949/1/add12469.pd

Alcohol, Tobacco, and Other Drugs: Future Directions for Screening and Intervention in the Emergency Department

This article is a product of a breakout session on injury prevention from the 2009 Academic Emergency Medicine consensus conference on “Public Health in the ED: Screening, Surveillance, and Intervention.” The emergency department (ED) is an important entry portal into the medical care system. Given the epidemiology of substance use among ED patients, the delivery of effective brief interventions (BIs) for alcohol, drug, and tobacco use in the ED has the potential to have a large public health impact. To date, the results of randomized controlled trials of interventional studies in the ED setting for substance use have been mixed in regard to alcohol and understudied in the area of tobacco and other drugs. As a result, there are more questions remaining than answered. The work group developed the following research recommendations that are essential for the field of screening and BI for alcohol, tobacco, and other drugs in the ED. 1) Screening—develop and validate brief and practical screening instruments for ED patients and determine the optimal method for the administration of screening instruments. 2) Key components and delivery methods for intervention—conduct research on the effectiveness of screening, brief intervention, and referral to treatment (SBIRT) in the ED on outcomes (e.g., consumption, associated risk behaviors, and medical psychosocial consequences) including minimum dose needed, key components, optimal delivery method, interventions focused on multiple risk behaviors and tailored based on assessment, and strategies for addressing polysubstance use. 3) Effectiveness among patient subgroups—conduct research to determine which patients are most likely to benefit from a BI for substance use, including research on moderators and mediators of intervention effectiveness, and examine special populations using culturally and developmentally appropriate interventions. 4) Referral strategies—a) promote prospective effectiveness trials to test best strategies to facilitate referrals and access from the ED to preventive services, community resources, and substance abuse and mental health treatment; b) examine impact of available community services; c) examine the role of stigma of referral and follow-up; and d) examine alternatives to specialized treatment referral. 5) Translation—conduct translational and cost-effectiveness research of proven efficacious interventions, with attention to fidelity, to move ED SBIRT from research to practice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78664/1/j.1553-2712.2009.00552.x.pd

Comparative analysis of conjugated alkynyl chromophore-triazacyclononane ligands for sensitized emission of europium and terbium

A series of europium and terbium complexes based on a functionalized triazacyclononane carboxylate or phosphinate macrocyclic ligand is described. The influence of the anionic group, that is, carboxylate, methylphosphinate, or phenylphosphinate, on the photophysical properties was studied and rationalized on the basis of DFT calculated structures. The nature, number, and position of electron-donating or electron-withdrawing aryl substituents were varied systematically within the same phenylethynyl scaffold in order to optimize the brightness of the corresponding europium complexes and investigate their two-photon absorption properties. Finally, the europium complexes were examined in cell-imaging applications, and selected terbium complexes were studied as potential oxygen sensors