71 research outputs found
Enterprise Computing
No full textDas vorliegende Buch entstand aus einer zweisemestrigen Vorlesung „Enterprise Computing“, die wir gemeinsam über viele Jahre als Teil des Bachelor- oder Master-Studienganges an der Universität Leipzig gehalten haben. Das Buch führt ein in die Welt des Mainframe und soll dem Leser einen einführenden Überblick geben. Band 1 ist der Einführung in z/OS gewidmet, während sich Band 2 mit der Internet Integration beschäftigt. Ergänzend werden in Band 3 praktische Übungen unter z/OS dargestellt
Notes On "Open" Addressing
No full textIntroduction and Definitions. Open addressing is a widely--used technique for keeping "symbol tables." The method was first used in 1954 by Samuel, Amdahl, and Boehme in an assembly program for the IBM 701. An extensive discussion of the method was given by Peterson in 1957 [1], and frequent references have been made to it ever since (e.g. Schay and Spruth [2], Iverson [3]). However, the timing characteristics have apparently never been exactly established, and indeed the author has heard reports of several reputable mathematicians who failed to find the solutions after some trial. Therefore it is the purpose of this note to indicate one way by which the solution can be obtained. We will use the following abstract model to describe the method: N is a positive integer, and we have an array of N variables x 1 ; x 2 ; : : : ; xN . At the beginning, x i = 0, for
Sodium ion dependence of inhibition of the Na+-translocating F1F0-ATPase from Acetobacterium woodii. Probing the site(s) involved in ion transport
No full textAbstractThe Na+-translocating F1F0-ATPase of Acetobacterium woodii was stimulated not only by Na+ but also by Li+ and was protected by Na+ or Li+ from inactivation by N,N′-dicyclohexylcarbodiimide (DCCD), diethylstilbestrol (DES) and tributyltin (TBSn) but not N-ethylmaleimide (NEM) or azide. The amount of Na+ required for half-maximal protection from DCCD inhibition corresponded to the apparent Km for Na+ of ATP hydrolysis. The inhibition by the amiloride derivatives hexamethylene-amiloride (HMA), ethylisopropylamiloride (EIPA), N-10-benzyl-amiloride (benzamil) and N-10-phenamil-amiloride (phenamil) could be relieved by Na+ to various degrees. EIPA and HMA effectively protected the ATPase from DCCD inactivation, whereas the protection by benzamil and phenamil was only marginal indicating that the unsubstituted guanidinium group is essential for maximal protection from DCCD inactivation. These results indicate that the amiloride derivatives and Na+ or DCCD compete for a common binding site. Chemical modification of histidine, arginine, aspartate or glutamate residues of the F1F0, complex resulted in an inhibition of ATP hydrolysis, indicating an essential function of these residues in the catalytic mechanism but this inhibition could not be relieved by Na+
Self-Learning Prediciton System for Optimisation of Workload Managememt in a Mainframe Operating System
No full textWe present a framework for extraction and prediction of online workload data from a workload manager of a mainframe operating system. To boost overall system performance, the prediction will be corporated
into the workload manager to take preventive action before a bottleneck develops. Model and feature selection automatically create a prediction model based on given training data, thereby keeping the system
flexible. We tailor data extraction, preprocessing and training to this specific task, keeping in mind the nonstationarity of business processes. Using error measures suited to our task, we show that our approach is promising. To conclude, we discuss our first results and give an outlook on future work
Structural integrity in subjective cognitive decline, mild cognitive impairment and Alzheimer’s disease based on multicenter diffusion tensor imaging
No full textExploring neural correlates of automated speech-based cognitive markers through resting-state functional connectivity in aging and at-risk Alzheimer’s disease
No full textAbstract Background Digital speech-based assessments provide scalable tools for detecting subtle cognitive decline. Here, we investigated whether digitally derived speech-based composite score of cognition and individual speech features were associated with alterations in functional connectivity (FC) within task-related brain networks in the Alzheimer’s disease spectrum, which are known to reflect cognitive performance and disease-related changes. Methods Data were analyzed from 129 participants of the German PROSPECT-AD study, ranging from cognitively healthy individuals to those with mild cognitive impairment. Speech-based cognitive scores and speech features were derived from automated phone-administered semantic verbal fluency (SVF) and verbal learning tasks (VLT). Resting-state fMRI assessed FC, with intrinsic connectivity networks identified via independent component analysis and dual regression. Associations were examined using permutation-based voxel-wise regression, controlling for demographic and clinical covariates. Seed-to-voxel analyses were conducted to support network identification and complement findings. Results Greater language network connectivity in the left middle temporal gyrus was associated with increased SVF temporal cluster switching (FWE < .05, cluster size = 12 voxels, mean T = 3.86). Exploratory analyses (uncorrected p < .01) demonstrated no significant associations between cognitive composite scores and FC. However, individual SVF and VLT speech features exhibited network-specific associations across executive, language, and default mode networks, indicating exploratory yet spatially distinct connectivity patterns. Conclusion Digital speech-based assessments may have limited current utility for detecting FC alterations in at-risk individuals. Further validation using complementary methodological approaches, shorter intervals between fMRI and speech assessments, and testing in independent cohorts, are essential to establish their reliability and clinical relevance for monitoring brain network changes
Associations between digital speech features of automated cognitive tasks and trajectories of brain atrophy and cognitive decline in early Alzheimer's disease
No full textBackground Speech-based features extracted from telephone-based cognitive tasks show promise for detecting cognitive decline in prodromal and manifest dementia. Little is known about the cerebral underpinnings of these speech features. Objective To examine associations between speech features, brain atrophy, and longitudinal cognitive decline in individuals at risk for Alzheimer's disease (AD). Methods Healthy volunteers, individuals with subjective cognitive decline, and those with mild cognitive impairment completed phonebot-guided semantic verbal fluency (SVF) and 15-word verbal learning task (VLT). Speech features were automatically extracted, and a global cognitive score (SB-C score) was computed. We analyzed data from 161 participants for cognitive trajectories, 141 for cross-sectional brain atrophy, and 102 for longitudinal brain changes. Analyses were conducted using multiple linear regressions, mixed-effects models, and voxel-based morphometry. Results The SB-C score was associated with bilateral hippocampal volumes, SVF features were primarily associated with left hemisphere regions, including the inferior frontal, parahippocampal, and superior/middle temporal gyri ( p uncorr < 0.001). SB-C score, SVF correct counts, and VLT delayed recall were associated with atrophy rates in the hippocampal/parahippocampal gyrus and left middle/inferior temporal gyri ( p FDR < 0.05). These features were also associated with cognitive decline assessed via Preclinical Alzheimer's Cognitive Composite 5, SVF, and Wordlist learning delayed recall ( p FDR < 0.01). Word frequency and temporal cluster switches showed varying associations with cognitive trajectories. Other features did not show robust associations. Conclusions In this study, we highlight the potential of digital speech features for identifying brain atrophy and cognitive decline over time in at-risk AD populations
Longitudinal Study of Antibody Reactivity against HIV-1 Envelope and a Peptide Representing a Conserved Site on Gp4l in HIV-1-Infected Patients
No full textMulticenter Tract-Based Analysis of Microstructural Lesions within the Alzheimer's Disease Spectrum: Association with Amyloid Pathology and Diagnostic Usefulness.
No full textpeer reviewedDiffusion changes as determined by diffusion tensor imaging are potential indicators of microstructural lesions in people with mild cognitive impairment (MCI), prodromal Alzheimer's disease (AD), and AD dementia. Here we extended the scope of analysis toward subjective cognitive complaints as a pre-MCI at risk stage of AD. In a cohort of 271 participants of the prospective DELCODE study, including 93 healthy controls and 98 subjective cognitive decline (SCD), 45 MCI, and 35 AD dementia cases, we found reductions of fiber tract integrity in limbic and association fiber tracts in MCI and AD dementia compared with controls in a tract-based analysis (p < 0.05, family wise error corrected). In contrast, people with SCD showed spatially restricted white matter alterations only for the mode of anisotropy and only at an uncorrected level of significance. DTI parameters yielded a high cross-validated diagnostic accuracy of almost 80% for the clinical diagnosis of MCI and the discrimination of Aβ positive MCI cases from Aβ negative controls. In contrast, DTI parameters reached only random level accuracy for the discrimination between Aβ positive SCD and control cases from Aβ negative controls. These findings suggest that in prodromal stages of AD, such as in Aβ positive MCI, multicenter DTI with prospectively harmonized acquisition parameters yields diagnostic accuracy meeting the criteria for a useful biomarker. In contrast, automated tract-based analysis of DTI parameters is not useful for the identification of preclinical AD, including Aβ positive SCD and control cases
Complement-Mediated Virus Infectivity Neutralisation by HLA Antibodies Is Associated with Sterilising Immunity to SIV Challenge in the Macaque Model for HIV/AIDS.
No full textSterilising immunity is a desired outcome for vaccination against human immunodeficiency virus (HIV) and has been observed in the macaque model using inactivated simian immunodeficiency virus (SIV). This protection was attributed to antibodies specific for cell proteins including human leucocyte antigens (HLA) class I and II incorporated into virions during vaccine and challenge virus preparation. We show here, using HLA bead arrays, that vaccinated macaques protected from virus challenge had higher serum antibody reactivity compared with non-protected animals. Moreover, reactivity was shown to be directed against HLA framework determinants. Previous studies failed to correlate serum antibody mediated virus neutralisation with protection and were confounded by cytotoxic effects. Using a virus entry assay based on TZM-bl cells we now report that, in the presence of complement, serum antibody titres that neutralise virus infectivity were higher in protected animals. We propose that complement-augmented virus neutralisation is a key factor in inducing sterilising immunity and may be difficult to achieve with HIV/SIV Env-based vaccines. Understanding how to overcome the apparent block of inactivated SIV vaccines to elicit anti-envelope protein antibodies that effectively engage the complement system could enable novel anti-HIV antibody vaccines that induce potent, virolytic serological response to be developed
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