Models for Testing Modifiable Systems

The work describes reliability and security growth models for modifiable software systems as a result of revisions and tests performed for specified input data areas. The work shows that the known reliability growth models are of monotonically increasing type, which is not in line with current multi-version team technologies of software development that are primarily based on the open-source code. The authors suggest new non-monotonically increasing models of software reliability evaluation and planning that allow taking into account the effect of decreased reliability resulting from updates or wavefront errors. The work describes the elaborated bigeminal and generic reliability evaluation model as well as the models and test planning procedures. The work includes calculated expressions for the evaluation of the model accuracy and shows that the developed models are adequate to real data. An example is given of transition from probability models to fuzzy models in case of incomplete basic data. The work provides general recommendations for selection of software tool testing models

Periodic Monitoring and Recovery of Resources in Information Systems

This section deals with the issues of business continuity and recovery after disasters. The authors analyzed standards, laws, and regulations pertaining to the parameters of periodic monitoring and recovery in information systems. This section includes mathematical models of resources and environment periodic monitoring as well as periodic backup and recovery after interruptions or disasters. The work demonstrates that the well-known deterministic periodic monitoring and backup models do not take into account stochastic peculiarities of ergatic systems to the full extent. The authors developed new stochastic models of restricted monitoring and backup that allow taking into consideration resources constrains and random factors of information systems operation. The notion of Bernoulli stream has been introduced. This section suggests the criteria for selecting deterministic or stochastic monitoring and backup models and their combinations. A solution of direct and reverse task of the calculation of control and monitoring procedures frequency is offered. This section also provides a methodology for information system stability management, considering periodic monitoring, rollback, and recovery in case of interruption

Device physics of polymer:fullerene bulk heterojunction solar cells

Plastic solar cells bear the potential for large-scale power generation based on materials that provide the possibility of flexible, lightweight, inexpensive, efficient solar cells. Since the discovery of the photoinduced electron transfer from a conjugated polymer to fullerene molecules, followed by the introduction of the bulk heterojunction (BHJ) concept, this material combination has been extensively studied in organic solar cells, leading to several breakthroughs in efficiency, with a power conversion efficiency approaching 5 %. This article reviews the processes and limitations that govern device operation of polymer.-fullerene BHJ solar cells, with respect to the charge-carrier transport and photogeneration mechanism. The transport of electrons/holes in the blend is a crucial parameter and must be controlled (e.g., by controlling the nanoscale morphology) and enhanced in order to allow fabrication of thicker films to maximize the absorption, without significant recombination losses. Concomitantly, a balanced transport of electrons and holes in the blend is needed to suppress the build-up of the space-charge that will significantly reduce the power conversion efficiency. Dissociation of electron-hole pairs at the donor/acceptor interface is an important process that limits the charge generation efficiency under normal operation condition. Based on these findings, there is a compromise between charge generation (light absorption) and open-circuit voltage (V-oc) when attempting to reduce the bandgap of the polymer (or fullerene). Therefore, an increase in V-oc of polymer.-fullerene cells, for example by raising the lowest unoccupied molecular orbital level of the fullerene, will benefit cell performance as both fill factor and short-circuit current increase simultaneously

Antitumor activity of Bulgarian herb Tribulus terrestris L. on human breast cancer cells

Medicinal plants have been intensively studied as a source of antitumor compounds. Due to the beneficial climate conditions Bulgarian herbs have high pharmacological potential. Currently, the antitumor effect of the Bulgarian medicinal plant Tribulus terrestris L. on human cancer cell lines is not studied. The main active compounds of the plant are the steroid saponins.The present study aims to analyze the effect on cell viability and apoptotic activity of total extract and saponin fraction of Bulgarian Tribulus terrestris L. on human breast cancer (MCF7) and normal (MCF10A) cell lines. Antitumor effect was established by МТТ cell viability assay and assessment of apoptotic potential was done through analysis of genomic integrity (DNA fragmentation assay) and analysis of morphological cell changes (Fluorescence microscopy). The results showed that total extract of the herb has a marked dose-dependent inhibitory effect on viability of MCF7 cells (half maximal inhibitory concentration is 15 μg/ml). Cell viability of MCF10A was moderately decreased without visible dose-dependent effect. The saponin fraction has increased inhibitory effect on breast cancer cells compared to total extract. Morphological changes and DNA fragmentation were observed as markers for early and late apoptosis predominantly in tumor cells after treatment. Apoptotic processes were intensified with the increase of treatment duration.The obtained results are the first showing selective antitumor activity of Bulgarian Tribulus terrestris L. on human cancer cells in vitro. Apoptotic processes are involved in the antitumor mechanisms induced by the herb. This results give directions for future investigations concerning detailed assessment of its pharmacological potential

Геолого-промышленные типы месторождений германия, методика поисков и разведки

Recent genetic studies found the A allele of the variant rs1006737 in the alpha 1C subunit of the L-type voltage-gated calcium channel (CACNA1C) gene to be overrepresented in patients suffering from bipolar disorder, schizophrenia or major depression. While the functions underlying the pathophysiology of these psychiatric disorders are yet unknown, impaired performance in verbal fluency tasks is an often replicated finding. We investigated the influence of the rs1006737 single nucleotide polymorphism (SNP) on verbal fluency and its neural correlates.Brain activation was measured with functional magnetic resonance imaging (fMRI) during a semantic verbal fluency task in 63 healthy male individuals. They additionally performed more demanding verbal fluency tasks outside the scanner. All subjects were genotyped for CACNA1C rs1006737.For the behavioral measures outside the scanner, rs1006737genotype had an effect on semantic but not on lexical verbal fluency with decreased performance in risk-allele carriers. In the fMRI experiment, while there were no differences in behavioural performance, increased activation in the left inferior frontal gyrus as well as the left precuneus was found in risk-allele carriers in the semantic verbal fluency task.The rs1006737 variant does influence language production on a semantic level in conjunction with the underlying neural systems. These findings are in line with results of studies in bipolar disorder, schizophrenia and major depression and may explain some of the cognitive and brain activation variation found in these disorders

Some peculiarities of motion of neutral and charged test particles in the field of a spherically symmetric charged object in General Relativity

We propose the method of investigation of radial motions for charged and neutral test particles in the Reissner-Nordstr\"{o}m field by means of mass potential. In this context we analyze special features of interaction of charges and their motions in General Relativity and construct the radial motion classification. For test particles and a central source with charges $q$ and $Q$, respectively, the conditions of attraction (when $qQ>0$) and repulsion (when $qQ<0$) are obtained. The conditions of motionless test particle states with respect to the central source are investigated and, in addition, stability conditions for such static equilibrium states are found. It is shown that stable states are possible only for the bound states of weakly charged particles in the field of a naked singularity. Frequencies of small oscillations of test particles near their equilibrium positions are also found.Comment: 15 pages, 9 figure

The effects of a DTNBP1 gene variant on attention networks: an fMRI study

<p>Abstract</p> <p>Background</p> <p>Attention deficits belong to the main cognitive symptoms of schizophrenia and come along with altered neural activity in previously described cerebral networks. Given the high heritability of schizophrenia the question arises if impaired function of these networks is modulated by susceptibility genes and detectable in healthy risk allele carriers.</p> <p>Methods</p> <p>The present event-related fMRI study investigated the effect of the single nucleotide polymorphism (SNP) rs1018381 of the <it>DTNBP1 </it>(dystrobrevin-binding protein 1) gene on brain activity in 80 subjects while performing the attention network test (ANT). In this reaction time task three domains of attention are probed simultaneously: alerting, orienting and executive control of attention.</p> <p>Results</p> <p>Risk allele carriers showed impaired performance in the executive control condition associated with reduced neural activity in the left superior frontal gyrus [Brodmann area (BA) 9]. Risk allele carriers did not show alterations in the alerting and orienting networks.</p> <p>Conclusions</p> <p>BA 9 is a key region of schizophrenia pathology and belongs to a network that has been shown previously to be involved in impaired executive control mechanisms in schizophrenia. Our results identified the impact of <it>DTNBP1 </it>on the development of a specific attention deficit via modulation of a left prefrontal network.</p

Subclinical Hypothyroidism after Radioiodine Exposure: Ukrainian–American Cohort Study of Thyroid Cancer and Other Thyroid Diseases after the Chornobyl Accident (1998–2000)

BackgroundHypothyroidism is the most common thyroid abnormality in patients treated with high doses of iodine-131 (131I). Data on risk of hypothyroidism from low to moderate 131I thyroid doses are limited and inconsistent.ObjectiveThis study was conducted to quantify the risk of hypothyroidism prevalence in relation to 131I doses received because of the Chornobyl accident.MethodsThis is a cross-sectional (1998-2000) screening study of thyroid diseases in a cohort of 11,853 individuals &lt; 18 years of age at the time of the accident, with individual thyroid radioactivity measurements taken within 2 months of the accident. We measured thyroid-stimulating hormone (TSH), free thyroxine, and antibodies to thyroid peroxidase (ATPO) in serum.ResultsMean age at examination of the analysis cohort was 21.6 years (range, 12.2-32.5 years), with 49% females. Mean 131I thyroid dose was 0.79 Gy (range, 0-40.7 Gy). There were 719 cases with hypothyroidism (TSH &gt; 4 mIU/L), including 14 with overt hypothyroidism. We found a significant, small association between (131)I thyroid doses and prevalent hypothyroidism, with the excess odds ratio (EOR) per gray of 0.10 (95% confidence interval, 0.03-0.21). EOR per gray was higher in individuals with ATPO &lt; or = 60 U/mL compared with individuals with ATPO &gt; 60 U/mL (p &lt; 0.001).ConclusionsThis is the first study to find a significant relationship between prevalence of hypothyroidism and individual (131)I thyroid doses due to environmental exposure. The radiation increase in hypothyroidism was small (10% per Gy) and limited largely to subclinical hypothyroidism. Prospective data are needed to evaluate the dynamics of radiation-related hypothyroidism and clarify the role of antithyroid antibodies