Stochastic resonance in a nanoscale Y-branch switch

The self-gating effect in a nanoscale Y-branch switch was exploited to tune the bistable switching so small that noise induced switching occurs. In this regime, the time-dependent response to a weak external periodic signal was studied. The noise-activated switching of the junction was synchronized with the weak external periodic signal due to the presence of the sole internal noise. A maximum synchronization is found and interpreted in terms of stochastic resonance

Teacher perceptions of citizenship education in social studies 30-1

The purpose of this research was to gain a better understanding of the perspectives on and the treatment and assessment of citizenship education by Social Studies 30-1 teachers. A convergent parallel mixed methods approach was employed through a survey combining Likert scale questions, numerical response questions and open-ended questions, in which 21 teachers participated and follow-up interviews in which six of the original 21 participants took part in. The results of the show that there is a high degree of alignment between the construct of citizenship and what the vast majority of participants believe citizenship education is and what it should be. It also showed that there was a lack of alignment between citizenship and Social Studies Program of Studies and even greater lack of alignment with the diploma exam. One of the consequences of this lack of alignment combined with the large role the diploma exam plays in shaping teachers’ practices is that citizenship education often becomes a secondary focus behind the diploma exam

Validierung innerklinischer Sichtungsalgorithmen für den Massenanfall von Verletzten

Background In the event of a mass casualty incident (MCI), the situation-related shortage of medical resources does not end when the patients are transported from the scene of the incident. Consequently, an initial triage is required in the receiving hospitals. In the first step, the aim of this study was to create a reference patient vignette set with defined triage categories. This allowed a computer-aided evaluation of the diagnostic quality of triage algorithms for MCI situations in the second step. Methods A total of 250 case vignettes validated in practice were entered into a multistage evaluation process by initially 6 and later 36 triage experts. This algorithm—independent expert evaluation of all vignettes—served as the gold standard for analyzing the diagnostic quality of the following triage algorithms: Manchester triage system (MTS module MCI), emergency severity index (ESI), Berlin triage algorithm (BER), the prehospital algorithms PRIOR and mSTaRT, and two project algorithms from a cooperation between the Federal Office of Civil Protection and Disaster Assistance (BBK) and the Hashemite Kingdom of Jordan—intrahospital Jordanian-German project algorithm (JorD) and prehospital triage algorithm (PETRA). Each patient vignette underwent computerized triage through all specified algorithms to obtain comparative test quality outcomes. Results Of the original 250 vignettes, a triage reference database of 210 patient vignettes was validated independently of the algorithms. These formed the gold standard for comparison of the triage algorithms analyzed. Sensitivities for intrahospital detection of patients in triage category T1 ranged from 1.0 (BER, JorD, PRIOR) to 0.57 (MCI module MTS). Specificities ranged from 0.99 (MTS and PETRA) to 0.67 (PRIOR). Considering Youden’s index, BER (0.89) and JorD (0.88) had the best overall performance for detecting patients in triage category T1. Overtriage was most likely with PRIOR, and undertriage with the MCI module of MTS. Up to a decision for category T1, the algorithms require the following numbers of steps given as the median and interquartile range (IQR): ESI 1 (1–2), JorD 1 (1–4), PRIOR 3 (2–4), BER 3 (2–6), mSTaRT 3 (3–5), MTS 4 (4–5) and PETRA 6 (6–8). For the T2 and T3 categories the number of steps until a decision and the test quality of the algorithms are positively interrelated. Conclusion In the present study, transferability of preclinical algorithm-based primary triage results to clinical algorithm-based secondary triage results was demonstrated. The highest diagnostic quality for secondary triage was provided by the Berlin triage algorithm, followed by the Jordanian-German project algorithm for hospitals, which, however, also require the most algorithm steps until a decision

Validierung innerklinischer Sichtungsalgorithmen für den Massenanfall von Verletzten – eine simulationsbasierte Studie – deutsche Version

Hintergrund Die situationsbedingte Verknappung medizinischer Ressourcen endet bei einem Massenanfall von Verletzen (MANV) lageabhängig nicht mit dem Abtransport der Patienten von der Einsatzstelle. Folglich ist in den aufnehmenden Kliniken eine Eingangssichtung erforderlich. Ziel dieser Studie war es im ersten Schritt einen Referenz‐Patientenvignettensatz mit definierten Sichtungskategorien zu erstellen. Dies erlaubte im zweiten Schritt, die rechnergestützte Evaluation der diagnostischen Güte klinischer Sichtungsalgorithmen für MANV-Lagen. Methodik In einen mehrstufigen Bewertungsprozess durch zunächst sechs, später 36 Sichtungsexperten gingen 250 in der Übungspraxis validierte Fallvignetten ein. Diese Algorithmen – unabhängige Expertenbewertung aller Vignetten – dienten als Goldstandard für die Analyse der diagnostischen Güte der folgenden innerklinischen Algorithmen: Manchester Triage System (MTS Modul MANV), Emergency severity Index (ESI), Berliner Sichtungsalgorithmus (BER), die prähospitalen Algorithmen PRIOR und mSTaRT, sowie zwei Projektalgorithmen aus einer Kooperation des Bundesamts für Bevölkerungsschutz und Katastrophenhilfe (BBK) mit dem Haschemitischen Königreich Jordanien – innerklinischer jordanisch-deutscher Projektalgorithmus (JorD) und prähospitaler Sichtungsalgorithmus (PETRA). Jede Patientenvignette durchlief computergestützt eine Sichtung durch alle angegeben Algorithmen, um vergleichend die Testgüte für alle Verfahren zu erheben. Ergebnisse Von den ursprünglich 250 Vignetten konnte eine Sichtungsreferenzdatenbank mit 210 Patientenvignetten algorithmenunabhängig validiert werden. Diese bildeten den Goldstandard für den Vergleich der analysierten Sichtungsalgorithmen. Die Sensitivitäten für die innerklinische Detektion von Patienten der Sichtungskategorie I lagen zwischen 1,0 (BER, JorD, PRIOR) und 0,57 (MANV-Modul MTS). Die Spezifitäten lagen zwischen 0,99 (MTS und PETRA) und 0,67 (PRIOR). Gemessen am Youden-Index ergab sich bei BER (0,89) und JorD (0,88) die beste Gesamtperformance für die Detektion von Patienten der Sichtungskategorie I. Eine Übertriage ist am ehesten bei PRIOR, eine Untertriage beim MANV-Modul von MTS zu erwarten. Bis zum Entscheid SK I benötigen die Algorithmen folgende Schrittanzahlen (Median [IQR]): ESI 1 [1–2]; JorD 1 [1–4]; PRIOR 3 [2–4]; BER 3 [2–6]; mSTaRT 3 [3–5]; MTS 4 [4–5]; PETRA 6 [6–8]. Für die SK II und III besteht ein positiver Zusammenhang zwischen der Schrittanzahl bis zum Entscheid und der Testgüte. Schlussfolgerung In der vorliegenden Studie konnte eine Übertragbarkeit prähospitaler algorithmenbasierter Vorsichtungsergebnisse auf die Ergebnisse klinischer Algorithmen gezeigt werden. Die höchste diagnostische Güte für die innerklinischen Sichtung lieferten BER und JorD, die allerdings auch die meisten Algorithmusschritte bis zum Entscheid benötigen

Clinical Definitions of Pertussis: Summary of a Global Pertussis Initiative Roundtable Meeting, February 2011

Existing clinical case definitions of pertussis are decades old and based largely on clinical presentation in infants and children, yet an increasing burden is borne by adolescents and adults who may manifest distinct signs/symptoms. Therefore, a “one-size-fits-all” clinical case definition is no longer appropriate. Seeking to improve pertussis diagnosis, the Global Pertussis Initiative (GPI) developed an algorithm that delineates the signs/symptoms of pertussis most common to 3 age groups: 0–3 months, 4 months to 9 years, and ≥10 years. These case definitions are based on clinical presentation alone, but do include recommendations on laboratory diagnostics. Until pertussis can be accurately diagnosed, its burden will remain underestimated, making the introduction of epidemiologically appropriate preventive strategies difficult. The proposed definitions are intended to be widely applicable and to encourage the expanded use of laboratory diagnostics. Determination of their utility and their sensitivity and/or specificity versus existing case definitions is required

HLA Class I Restriction as a Possible Driving Force for Chikungunya Evolution

After two decades of quiescence, epidemic resurgence of Chikungunya fever (CHIKF) was reported in Africa, several islands in the Indian Ocean, South-East Asia and the Pacific causing unprecedented morbidity with some cases of fatality. Early phylogenetic analyses based on partial sequences of Chikungunya virus (CHIKV) have led to speculation that the virus behind recent epidemics may result in greater pathogenicity. To understand the reasons for these new epidemics, we first performed extensive analyses of existing CHIKV sequences from its introduction in 1952 to 2009. Our results revealed the existence of a continuous genotypic lineage, suggesting selective pressure is active in CHIKV evolution. We further showed that CHIKV is undergoing mild positive selection, and that site-specific mutations may be driven by cell-mediated immune pressure, with occasional changes that resulted in the loss of human leukocyte antigen (HLA) class I-restricting elements. These findings provide a basis to understand Chikungunya virus evolution and reveal the power of post-genomic analyses to understand CHIKV and other viral epidemiology. Such an approach is useful for studying the impact of host immunity on pathogen evolution, and may help identify appropriate antigens suitable for subunit vaccine formulations

The epidemiology of pertussis in Germany: past and present

<p>Abstract</p> <p>Background</p> <p>Current and past pertussis epidemiology in the two parts of Germany is compared in the context of different histories of vaccination recommendations and coverage to better understand patterns of disease transmission.</p> <p>Methods</p> <p>Available regional pertussis surveillance and vaccination coverage data, supplemented by a literature search for published surveys as well as official national hospital and mortality statistics, were analyzed in the context of respective vaccination recommendations from 1964 onwards.</p> <p>Results</p> <p>Routine childhood pertussis vaccination was recommended in the German Democratic Republic (GDR) from 1964 and in former West German states (FWG) from 1969, but withdrawn from 1974–1991 in FWG. Pertussis incidence declined to <1 case/100.000 inhabitants in GDR prior to reunification in 1991, while in FWG, where pertussis was not notifiable after 1961, incidence was estimated at 160–180 cases/100.000 inhabitants in the 1970s-1980s. Despite recommendations for universal childhood immunization in 1991, vaccination coverage decreased in former East German States (FEG) and increased only slowly in FWG. After introduction of acellular pertussis vaccines in 1995, vaccination coverage increased markedly among younger children, but remains low in adolescents, especially in FWG, despite introduction of a booster vaccination for 9–17 year olds in 2000. Reported pertussis incidence increased in FEG to 39.3 cases/100.000 inhabitants in 2007, with the proportion of adults increasing from 20% in 1995 to 68% in 2007. From 2004–2007, incidence was highest among 5–14 year-old children, with a high proportion fully vaccinated according to official recommendations, which did not include a preschool booster until 2006. Hospital discharge statistics revealed a ~2-fold higher pertussis morbidity among infants in FWG than FEG.</p> <p>Conclusion</p> <p>The shift in pertussis morbidity to older age groups observed in FEG is similar to reports from other countries with longstanding vaccination programs and suggests that additional booster vaccination may be necessary beyond adolescence. The high proportion of fully vaccinated cases in older children in FEG suggests waning immunity 5–10 years after primary immunisation in infancy. The higher incidence of pertussis hospitalisations in infants suggests a stronger force of infection in FWG than FEG. Nationwide pertussis reporting is required for better evaluation of transmission patterns and vaccination policy in both parts of Germany.</p

Cost-Effectiveness of Adolescent Pertussis Vaccination for The Netherlands: Using an Individual-Based Dynamic Model

BACKGROUND: Despite widespread immunization programs, a clear increase in pertussis incidence is apparent in many developed countries during the last decades. Consequently, additional immunization strategies are considered to reduce the burden of disease. The aim of this study is to design an individual-based stochastic dynamic framework to model pertussis transmission in the population in order to predict the epidemiologic and economic consequences of the implementation of universal booster vaccination programs. Using this framework, we estimate the cost-effectiveness of universal adolescent pertussis booster vaccination at the age of 12 years in the Netherlands. METHODS/PRINCIPAL FINDINGS: We designed a discrete event simulation (DES) model to predict the epidemiological and economic consequences of implementing universal adolescent booster vaccination. We used national age-specific notification data over the period 1996-2000--corrected for underreporting--to calibrate the model assuming a steady state situation. Subsequently, booster vaccination was introduced. Input parameters of the model were derived from literature, national data sources (e.g. costing data, incidence and hospitalization data) and expert opinions. As there is no consensus on the duration of immunity acquired by natural infection, we considered two scenarios for this duration of protection (i.e. 8 and 15 years). In both scenarios, total pertussis incidence decreased as a result of adolescent vaccination. From a societal perspective, the cost-effectiveness was estimated at €4418/QALY (range: 3205-6364 € per QALY) and €6371/QALY (range: 4139-9549 € per QALY) for the 8- and 15-year protection scenarios, respectively. Sensitivity analyses revealed that the outcomes are most sensitive to the quality of life weights used for pertussis disease. CONCLUSIONS/SIGNIFICANCE: To our knowledge we designed the first individual-based dynamic framework to model pertussis transmission in the population. This study indicates that adolescent pertussis vaccination is likely to be a cost-effective intervention for The Netherlands. The model is suited to investigate further pertussis booster vaccination strategies

Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe