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The stock exchanges of CEE countries constitute a minor part of the capital of the entire Europe, but they are dynamically developing and cooperating capital markets. After 30 years of development, it seems reasonable whether the processes of asset pricing in them are aimed at the efficiency level of developed markets and are subject to the postulates of pricing models, such as CAPM. The work aims to test the standard CAPM using the CEE country indices. Apart from the classical approach, conditional regressions in relation to the global market condition are an important contribution to the research. The obtained results indicate that the significance of the risk premium, largely depends on the sign of the market returns, showing the advantage of conditional relations over unconditional ones. The research analyzed the sensitivity of the results to the existing socio-political crises and assessed the risk of selected stock exchanges. [ABSTRACT FROM AUTHOR]

Mites are masters at attaching to larger animals, often insects, in a temporary symbiosis called phoresy that allows these tiny animals to exploit patchy resources. In this article, we examine phoresy in the Acari, including those that feed on their carriers in transit, from a broad perspective. From a phylogenetic perspective, phoresy has evolved several times from free-living ancestors but also has been lost frequently. Rotting logs appear to be the first patchy resource exploited by phoretic mites, but the evolution of rapid life cycles later permitted exploitation of short-lived resources. As phoresy is a temporary symbiosis, most species have off-host interactions with their carrier. These relationships can be highly complex and context dependent but often are exploitative of the carrier's resources or progeny. Transitions from phoresy to parasitism seem widespread, but evidence for transitions from obligate phoretic parasitism to permanent parasitism is weak. [ABSTRACT FROM AUTHOR]

In the Life Sciences ‘omics’ data is increasingly generated by different high-throughput technologies. Often only the integration of these data allows uncovering biological insights that can be experimentally validated or mechanistically modelled, i.e. sophisticated computational approaches are required to extract the complex non-linear trends present in omics data. Classification techniques allow training a model based on variables (e.g. SNPs in genetic association studies) to separate different classes (e.g. healthy subjects versus patients). Random Forest (RF) is a versatile classification algorithm suited for the analysis of these large data sets. In the Life Sciences, RF is popular because RF classification models have a high-prediction accuracy and provide information on importance of variables for classification. For omics data, variables or conditional relations between variables are typically important for a subset of samples of the same class. For example: within a class of cancer patients certain SNP combinations may be important for a subset of patients that have a specific subtype of cancer, but not important for a different subset of patients. These conditional relationships can in principle be uncovered from the data with RF as these are implicitly taken into account by the algorithm during the creation of the classification model. This review details some of the to the best of our knowledge rarely or never used RF properties that allow maximizing the biological insights that can be extracted from complex omics data sets using RF. [ABSTRACT FROM PUBLISHER]

It has been argued that tasks that necessitate the use of context in the service of goal-directed behaviour are disrupted in both schizophrenic patients and in animal analogues by dopamine (DA) manipulation with the prefrontal cortex being implicated. To determine the effects on conditional discrimination performance of direct infusion of the DA D1/D2 receptor antagonist α-flupenthixol into the medial prefrontal cortex (mPFC) and of its reversal potential on d-amphetamine-induced task disruption. Conditional discrimination performance in which rats learn to respond on an appropriate lever, conditional upon specific auditory stimuli, was acquired and later tested under the above drug treatment protocol in extinction. Conditional discrimination performance was unaffected by bilateral intra-mPFC α-flupenthixol at doses of 12, 24 or 36 μg/μl. A dose of d-amphetamine (1.5 mg/kg) shown previously to disrupt conditional discrimination performance was attenuated by direct PFC infusion of α-flupenthixol at doses of 24 and 36 but not 12 μg/μl per site. These results show that conditional discrimination performance is at least in part mediated by prefrontal DA as local PFC DA antagonism attenuates task performance disruption by the indirect DA agonist d-amphetamine further implicating the role of dysfunctional forebrain DA in cognitive deficits evident in schizophrenia. [ABSTRACT FROM AUTHOR]

Forebrain dopamine (DA) manipulation has recently been shown to selectively disrupt a conditional discrimination task whose design parameters approximate tasks repeatedly shown to be impaired in schizophrenia. To investigate the reversal potential of the D1/D2 receptor antagonist α-flupenthixol, the selective D1 antagonist SCH 23390, the typical antipsychotic haloperidol and the atypical antipsychotic clozapine on acute phencyclidine (PCP)-induced disruption of a conditional discrimination task dependent on the ability to use task-setting cues that inform goal-directed performance. Rats learned a conditional discrimination task where reinforcement was contingent on an appropriate lever press during a specific auditory stimulus. PCP disrupted task performance at 1.5 mg/kg, attenuated correct lever pressing at 2.5 mg/kg and abolished overall responding at 5 mg/kg (experiment 1). Pavlovian-instrumental transfer task results (experiment 2) showed that 1.5 and 2.5 mg/kg PCP had no disruptive effects on basic sensory, motor or motivational processes; however, such deficits were evident in 5-mg/kg-treated animals. PCP (1.5 mg/kg) disruption of conditional discrimination was attenuated by acute pretreatment with clozapine, SCH 23390 and α-flupenthixol; however, pretreatment with haloperidol did not attenuate task disruption. The predictive validity of the conditional discrimination model is enhanced as the selective task disruption by the preeminent psychotomimetic PCP is reversed by clozapine (known to ameliorate cognitive deficits in schizophrenia) and the role of DA D1 receptors as mediators of tasks that require conditional relationships is discussed. [ABSTRACT FROM AUTHOR]

Recent experimental findings suggest that a core cognitive deficit of schizophrenia is the degraded ability to use task-setting cues to guide goal-directed behaviour, that this deficit is evident in acute as well as chronic schizophrenia, and that such deficits can me modelled in animals using conditional discrimination tasks. To establish the reversal potential of D1, D2 and 5-HT receptor antagonists acutely, and D1 and D2 receptor antagonists chronically, on d-amphetamine-induced disruption of a conditional discrimination task that depends on the ability to use task-setting cues to direct goal directed performance. A conditional discrimination paradigm was employed in which rats learned to respond on an appropriate lever, conditional upon specific auditory stimuli. d-Amphetamine (1.5 mg/kg) disruption of conditional discrimination was attenuated by acute pre-treatment with the selective D1 antagonist SCH 23390 and the atypical anti-psychotic clozapine (Cloz). Acute pre-treatment with the selective D2 antagonist eticlopride (Eti) and the anti-psychotic haloperidol (Hal) failed to reverse d-amphetamine disruption, as did pre-treatment with the selective 5HT1A antagonist WAY 100635 and the selective 5HT2A/C antagonist ritanserin. However, Eti and Hal did reverse d-amphetamine-induced task disruption when administered chronically (as did SCH 23390, α-flupenthixol and Cloz). These results suggest that D1 receptors are involved in tasks that require the use of conditional relationships and that D2 receptor antagonism can come to exert a similar influence after chronic treatment. [ABSTRACT FROM AUTHOR]