Is HIV/AIDS in Africa distinct? What can we learn from an analysis of the literature?

This paper investigates, through an analysis of the published literature, the notion held by several people that HIV/AIDS in Africa is unique. Using co-word and multidimensional scaling (MDS) analyses of MEDLINE-extracted HIV/AIDS records, this study used five lists of terms to investigate the related-ness of various factors and diseases to HIV/AIDS. The lists consisted of risk factors, sexually transmitted diseases, tropical diseases, opportunistic diseases, and pre-disposing factors. Data (i.e. words.txt — consisting of keywords/phrases describing the aforementioned factors and diseases; and text.txt — containing HIV/AIDS papers’ titles) were analyzed using TI computer-aided application software, developed by Leydesdorff. Results revealed that several factors and diseases that are pre-dominant in Sub-Saharan Africa exhibited strong and high pattern of co-occurrences with HIV/AIDS, implying close associated-ness with the epidemic in the region. Further areas of research, whose results will be used to make conclusive observations and arguments concerning the uniqueness of HIV/AIDS in Sub-Saharan Africa, are recommended.     

Comparing problem formulations for coupled sets of components

This paper presents several formulations and comparative test results for problems involving the general paradigm of coupled sets of components (CSoC). This paradigm is general enough to include systems of systems (SoS) under any of the various definitions, as well as multidisciplinary design optimization (MDO). It is assumed that a CSoC involves a (potentially inactive) coordinating component, or “Central Authority”, and one or more, potentially interacting, subordinate components. The formulations differ in the amount of control given to the CA versus the autonomy granted to the subordinate components. In this generality, satisfaction of equilibrium conditions replaces the optimality condition in defining a solution. A solution still requires feasibility of all constraints. The desirability of a particular equilibrium point depends on the specific problem being studied and the component algorithms used to obtain that equilibrium. These concepts are illustrated using comparative test results for several of the formulations on a NASA-generated, public domain, aircraft conceptual design problem.     

Method detection limit determination and application of a convenient headspace analysis method for methyl tert-butyl ether in water

Methyl tert-butyl ether (MTBE) is a common groundwater contaminant, introduced to the environment by leaking petroleum storage tanks, urban runoff, and motorized watercraft. In this study. a simplified (static) headspace analysis method was adapted for determination of MTBE in water samples and soil water extracts. The MDL of the headspace method was calculated to be 2.0 microg L(-1) by the EPA single-concentration design method(1) and 1.2 microg L(-1) by a calibration method developed by Hubaux and Vos (Hubaux, A.; Vos, G. Anal. Chem. 1970,42, 849-855). The MDL calculated with the Hubaux and Vos method was favored because it considers both a true positive and a false positive. The static headspace method was applied to analysis of a tap water sample and a monitoring well sample from a gasoline service station, a river sample, and aqueous extracts from soil excavated during removal of a leaking underground storage tank (LUST). The water samples examined in this study had MTTBE concentrations ranging from 6 to 19 microg L(-1). Aqueous extracts of a soil sample taken from the LUST site had 8 microg L(-1) MTBE.     

Long-term effects of behavior therapy: A 12-month follow-up.

19 female undergraduates who underwent various behavioral treatments designed to reduce a specific fear were paid to return for follow-up 1 yr. later. In general, treated Ss' rat fears were less intense 1 yr. after treatment than they had been prior to treatment, with those treated by systematic desensitization slightly less fearful than those treated with "rational therapy." Subsequently, the desensitized Ss eliminated a snake fear by themselves, but the effects of this self-administered desensitization were not maintained. Additionally, 6 children treated by operant conditioning techniques for various problems were reevaluated 1 yr. later. All behavior change was maintained, but only those who had graduated to social reinforcement showed additional improvement. No evidence for symptom substitution was obtained from either group of Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differentiation of organics from schizophrenics at two chronicity levels by use of the Reitan-Halstead Organic Test Battery.

Attempted to determine whether the Reitan-Halstead Organic Test Battery separates neuropsychiatric hospital organics from schizophrenics. It was administered to 25 schizophrenics and 25 cerebral-lesion organics at each of 2 chronicity levels. Only 1 of the 24 diagnosis/diagnosis * chronicity effects used to evaluate the data was significant at the .05 level, indicating that actuarial application of Reitan-Halstead scores is of no practical value in the separation of the 2 groups. To determine whether expert clinicians might improve upon the actuarial results, protocols of 24 schizophrenics and 24 organics were sent to 8 Reitan-Halstead experts who were instructed to separate them into brain-damaged and schizophrenic diagnostic groups. The mean number of correct classifications, 25.5 out of 48 suggested that clinical judgment added nothing to actuarial prediction in this case. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A practitioner's guide to data base compression tutorial

Data compression techniques can improve information system performance by reducing the size of a database by as much as ninety percent. This paper is written to provide assistance to practitioners considering the use of data compression for the storage of a commercial database. It reviews a wealth of literature on data compression and presents facts and guidelines which will assist system designers in evaluating the costs and benefits of compression and in selecting techniques appropriate for their needs.     

Estimating frequency-response function using periodic signals and the f.f.t.

A technique for estimating a frequency-response function using a periodic pseudorandom binary sequence which is compatible with the fast-Fourier-transform algorithm is presented. A method of synchronising the p.r.b.s. and the sampling for the f.f.t. using a single clock source and two binary counters is described. A simple check on the synchronisations and the identification of an 8th-order lowpass Butterworth filter is provided.