Hierarchical Poly Tree Configurations for the Solution of Dynamically Refined Finte Element Models

This paper demonstrates how a multilevel substructuring technique, called the Hierarchical Poly Tree (HPT), can be used to integrate a localized mesh refinement into the original finite element model more efficiently. The optimal HPT configurations for solving isoparametrically square h-, p-, and hp-extensions on single and multiprocessor computers is derived. In addition, the reduced number of stiffness matrix elements that must be stored when employing this type of solution strategy is quantified. Moreover, the HPT inherently provides localize 'error-trapping' and a logical, efficient means with which to isolate physically anomalous and analytically singular behavior

Nevirapine (NVP), tenofovir (TDF) and lamivudine (3TC) or emtricitabine (FTC) is effective and well tolerated in naïve HIV-1 infected patients

Background: The combination of stavudine (d4T), 3TC and NVP was the WHO recommended first-line regimen for the treatment of naïve HIV-1 infected patients in resource-limited settings. But peripheral polyneuropathy, lipoatrophy and symptomatic hyperlactatemia are frequent and treatment-limiting adverse events associated with stavudine, especially when combined with antituberculous drugs. Tenofovir combined with lamivudine and efavirenz has proven excellent efficacy, but there is little experience when given with NVP. Methods: Retrospective analysis of all patients receiving TDF, NVP and 3TC or FTC as first-line treatment in the Frankfurt HIV cohort. Summary of results: 70 patients (15 female) with a median CD4 cell count of 210/μl (47–949) and HIV-RNA PCR of 140,000 copies/ml (2,500–2,000,000) at baseline received TDF, NVP and 3TC/FTC, and were treated for a median of 68 weeks (16–278). CD4 cells rose up to cells/μl 322 (119–1075) and 75% of the patients remained on treatment. All patients on treatment at week 48 were 100,000 c/m. Reasons for discontinuation (24%) were mainly adverse events (13%), with rash (7%) and liver toxicity (6%) being the two most common, whereas virologic failure, drug interaction and non-adherence were all relatively rare (each 3%). Conclusion: The combination of NVP, TDF and 3TC or FTC is effective and well tolerated in previously naïve HIV-1 infected patients even when started with low CD4 cell counts (100,000 c/ml). In the latest amendment of the WHO guidelines TDF, instead of d4T, is the recommended first-line treatment in resource-limited settings

Spatiotemporal modeling of schistosomiasis in Ghana: linking remote sensing data to infectious disease

More than 90% of the worldwide schistosomiasis burden falls on sub-Saharan Africa. Control efforts are often based on infrequent, small-scale health surveys, which are expensive and logistically difficult to conduct. The use of satellite imagery to predictively model infectious disease transmission has great potential for public health applications. The transmission of schistosomiasis, a disease acquired from contact with contaminated surface water, requires specific environmental conditions to sustain freshwater snails. If a connection between schistosomiasis and remotely sensed environmental variables can be established, then cost effective and current disease risk predictions can be made available. Schistosomiasis transmission has unknown seasonality, and the disease is difficult to study due to a long lag between infection and clinical symptoms. To overcome these challenges, we employed a comprehensive 15-year time-series built from remote sensing feeds, which is the longest environmental dataset to be used in the application of remote sensing to schistosomiasis. The following environmental variables will be used in the model: accumulated precipitation, land surface temperature, vegetative growth indices, and climate zones created from a novel climate regionalization technique. This technique, improves upon the conventional Köppen-Geiger method, which has been the primary climate classification system in use the past 100 years. These predictor variables will be regressed against 8 years of national health data in Ghana, the largest health dataset of its kind to be used in this context, and acquired from freely available satellite imagery data. A benefit of remote sensing processing is that it only requires training and time in terms of resources. The results of a fixed effects model can be used to develop a decision support framework to design treatment schemes and direct scarce resources to areas with the highest risk of infection. This framework can be applied to diseases sensitive to climate or to locations where remote sensing would be better suited than health surveys.Published versio

Grenzen der Überdruckbarkeit

Im Rahmen dieser Forschungsarbeiten werden die Grenzen der Überdruckbarkeit unterschiedlicher Materialien und unter Einwirkung eines Dickensprungs mit verschiedenen Druckverfahren ermittelt. Der Dickensprung wurde durch das Aufspenden von verschiedenen Folien-, Papier-, EAS-Etiketten und eine Lackschicht erzeugt. Als Substrate wurden Etikettenpapier, Bilderdruckpapier und Polypropylenfolie verwendet. Für die Untersuchung der Überdruckbarkeit werden die Druckverfahren Offsetdruck, Flexodruck und Inkjet-Druck eingesetzt. Es soll die Frage beantwortet werden, welche Schichtdicken mit welcher Qualität überdruckt werden können. Von besonderem Interesse ist neben der Oberflächen¬beschaffenheit der gedruckten Schichten auch der Kantenübergang zwischen den zu überdruckenden Schichten. In 330 Versuchseinstellungen wurden nach der Methode der statistischen Versuchsplanung Proben auf einer industriellen Rollendruckmaschine hergestellt. Dazu werden ca. 600 kg Farbe und Lack sowie ca. 210 000 Etiketten benötigt. Durch Messung von Glanz, Farbdichte und CIELab-Werten an verschiedenen Stellen werden die Proben charakterisiert. Weiterhin wurden zwei Versuchsreihen mit visuellen Abmusterungen durchgeführt. In der ersten Versuchsreihe werden 51 Probandenversuche (30 männlich, 20 weiblich) nach dem Prinzip des Paarvergleichs und der Rangfolge durchgeführt. Eine zweite Versuchsreihe wurde mit 3 Probanden (männlich) zur Profilierung der Druckqualität über alle 330 Versuchseinstellungen durchgeführt. Zur Bestimmung der Korrelationen werden auf die Ergebnisse statistische Verfahren angewendet. Bei der Varianzanalyse zeigte sich ein sehr großer Einfluss der Druckverfahren und der Sekundärschicht. Primärsubstrat, Siebdruckfluid und Siebdruckschichten haben einen großen Einfluss. Die Druckgeschwindigkeit hat einen vergleichsweise geringen Einfluss. Aus der Effektanalyse konnten wertvolle Detailerkenntnisse abgeleitet werden. Allerdings wurden bei beiden Verfahren auch die Grenzen hinsichtlich Datenqualität und Datenmenge deutlich. Die Proben und die Ergebnisse wurden in einer Mustermappe und in Versuchsprotokollen dokumentiert. Alle Daten und Bilder der Proben wurden in eine Excel-basierte Datenbank aufgenommen. Aus dieser Datenbank können alle Ergebnisse extrahiert werden. Weiterhin wurde auf Basis der Methode KNN (k nearest neighbour) folgende Möglichkeit implementiert: Auf Basis der eingegebenen Parameter wird die nächste wahrscheinliche Probe mit den Kennwerten und mit dem fotografierten Probenbild angezeigt

Assessment of liver fibrosis and associated risk factors in HIV-infected individuals using transient elastography and serum biomarkers

Background: Liver fibrosis in human immunodeficiency virus (HIV)-infected individuals is mostly attributable to co-infection with hepatitis B or C. The impact of other risk factors, including prolonged exposure to combined antiretroviral therapy (cART) is poorly understood. Our aim was to determine the prevalence of liver fibrosis and associated risk factors in HIV-infected individuals based on non-invasive fibrosis assessment using transient elastography (TE) and serum biomarkers (Fibrotest [FT]). Methods: In 202 consecutive HIV-infected individuals (159 men; mean age 47 ± 9 years; 35 with hepatitis-C-virus [HCV] co-infection), TE and FT were performed. Repeat TE examinations were conducted 1 and 2 years after study inclusion. Results: Significant liver fibrosis was present in 16% and 29% of patients, respectively, when assessed by TE (≥ 7.1 kPa) and FT (> 0.48). A combination of TE and FT predicted significant fibrosis in 8% of all patients (31% in HIV/HCV co-infected and 3% in HIV mono-infected individuals). Chronic ALT, AST and γ-GT elevation was present in 29%, 20% and 51% of all cART-exposed patients and in 19%, 8% and 45.5% of HIV mono-infected individuals. Overall, factors independently associated with significant fibrosis as assessed by TE (OR, 95% CI) were co-infection with HCV (7.29, 1.95-27.34), chronic AST (6.58, 1.30-33.25) and γ-GT (5.17, 1.56-17.08) elevation and time on dideoxynucleoside therapy (1.01, 1.00-1.02). In 68 HIV mono-infected individuals who had repeat TE examinations, TE values did not differ significantly during a median follow-up time of 24 months (median intra-patient changes at last TE examination relative to baseline: -0.2 kPa, p = 0.20). Conclusions: Chronic elevation of liver enzymes was observed in up to 45.5% of HIV mono-infected patients on cART. However, only a small subset had significant fibrosis as predicted by TE and FT. There was no evidence for fibrosis progression during follow-up TE examinations

The use of remotely sensed environmental parameters for spatial and temporal schistosomiasis prediction across climate zones in Ghana

Schistosomiasis control in sub-Saharan Africa is enacted primarily through preventive chemotherapy. Predictive models can play an important role in filling knowledge gaps in the distribution of the disease and help guide the allocation of limited resources. Previous modeling approaches have used localized cross-sectional survey data and environmental data typically collected at a discrete point in time. In this analysis, 8 years (2008-2015) of monthly schistosomiasis cases reported into Ghana's national surveillance system were used to assess temporal and spatial relationships between disease rates and three remotely sensed environmental variables: land surface temperature (LST), normalized difference vegetation index (NDVI), and accumulated precipitation (AP). Furthermore, the analysis was stratified by three major and nine minor climate zones, defined using a new climate classification method. Results showed a downward trend in reported disease rates (~ 1% per month) for all climate zones. Seasonality was present in the north with two peaks (March and September), and in the middle of the country with a single peak (July). Lowest disease rates were observed in December/January across climate zones. Seasonal patterns in the environmental variables and their associations with reported schistosomiasis infection rates varied across climate zones. Precipitation consistently demonstrated a positive association with disease outcome, with a 1-cm increase in rainfall contributing a 0.3-1.6% increase in monthly reported schistosomiasis infection rates. Generally, surveillance of neglected tropical diseases (NTDs) in low-income countries continues to suffer from data quality issues. However, with systematic improvements, our approach demonstrates a way for health departments to use routine surveillance data in combination with publicly available remote sensing data to analyze disease patterns with wide geographic coverage and varying levels of spatial and temporal aggregation.Accepted manuscrip

The HERMES Back Drift Chambers

The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibration, resolution, and efficiencies, and a discussion of the experience gained through the first three years of operation.Comment: 21 pages, LaTex, 16 figures include

Internal Perceptions: A Look at the Fayetteville Police Department\u27s Partnership with Social Workers

The development of co-response models where law enforcement partner with social workers or mental health clinicians to respond to individuals in mental health crises or with other social needs is on the rise throughout the United States. The Fayetteville, AR Police Department (FPD) developed their program with a University of Arkansas School of Social Work (UA) intern in 2021. The newly created Crisis Intervention Response Team (CIRT) now has two full-time, two-person co-response teams along with two social work interns and has plans for growth. This study looks at FPD sworn and civilian employees’ perceptions of embedding social workers/advocates into their department. Results and discussion highlight factors that have made the program work thus far, lessons learned, and suggestions for program improvement as it continues to grow

Internal Perceptions: A Look at the Fayetteville Police Department\u27s Partnership with Social Workers

The development of co-response models where law enforcement partner with social workers or mental health clinicians to respond to individuals in mental health crises or with other social needs is on the rise throughout the United States. The Fayetteville, AR Police Department (FPD) developed their program with a University of Arkansas School of Social Work (UA) intern in 2021. The newly created Crisis Intervention Response Team (CIRT) now has two full-time, two-person co-response teams along with two social work interns and has plans for growth. This study looks at FPD sworn and civilian employees’ perceptions of embedding social workers/advocates into their department. Results and discussion highlight factors that have made the program work thus far, lessons learned, and suggestions for program improvement as it continues to grow