539 research outputs found

    Reactive Mechanism of Cognitive Control System

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    The prefrontal cortex (PFC) is thought to modulate the neural network state in favor of the processing of task-relevant sensory information prior to the presentation of sensory stimuli. However, this proactive control mechanism cannot always optimize the network state because of intrinsic fluctuation of neural activity upon arrival of sensory information. In the present study, we have investigated an additional control mechanism, in which the control process to regulate the behavior is adjusted to the trial-by-trial fluctuation in neural representations of sensory information. We asked normal human subjects to perform a variant of the Stroop task. Using functional magnetic resonance imaging, we isolated cognitive conflict at a sensory processing stage on a single-trial basis by calculating the difference in activation between task-relevant and task-irrelevant sensory areas. Activation in the dorsolateral PFC (DLPFC) covaried with the neural estimate of sensory conflict only on incongruent trials. Also, the coupling between the DLPFC and anterior cingulate cortex (ACC) was tighter on high-sensory conflict trials with fast response. The results suggest that although detection of sensory conflict is achieved by the DLPFC, online behavioral adjustment is achieved by interactive mechanisms between the DLPFC and AC

    Phylogenetic Insights into RT and Vpx/Vpr

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    The efficiency of reverse transcription to synthesize viral DNA in infected cells greatly influences replication kinetics of retroviruses. However, viral replication in non-dividing cells such as resting T cells and terminally differentiated macrophages is potently and kinetically restricted by a host antiviral factor designated SAMHD1 (sterile alpha motif and HD-domain containing protein 1). SAMHD1 reduces cellular deoxynucleoside triphosphate (dNTP) pools and affects viral reverse transcription step. Human immunodeficiency virus type 2 (HIV-2) and some simian immunodeficiency viruses (SIVs) have Vpx or Vpr to efficiently degrade SAMHD1. Interestingly, the reverse transcriptase (RT) derived from HIV-1 that encodes no anti-SAMHD1 proteins has been previously demonstrated to uniquely exhibit a high enzymatic activity. It is thus not irrational to assume that some viruses may have acquired or lost the specific RT property to better adapt themselves to the low dNTP environments confronted in non-dividing cells. This adaptation process may probably be correlated with the SAMHD1-antagonizing ability by viruses. In this report, we asked whether such adaptive events can be inferable from Vpx/Vpr and RT phylogenetic trees overlaid with SAMHD1-degrading capacity of Vpx/Vpr and with kinetic characteristics of RT. Resultant two trees showed substantially similar clustering patterns, and therefore suggested that the properties of RT and Vpx/Vpr can be linked. In other words, HIV/SIVs may possess their own RT proteins to adequately react to various dNTP circumstances in target cells

    ダイガクセイ ニオケル スイコウ キノウ ト ショウドウセイ オヨビ テキオウ イヨク ノ カンレン

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    The purpose of this study was to examine the relationship between executive function, impulsivity, adjustment and motivation in undergraduates. On the first study, we used three self-report scales to measure impulsivity, adjustment and motivation. The results showed that impulsivity influenced lowering of motivation in undergraduates. On the other hand, a decrease in an adjustment couldn’t be explained only by impulsivity. On the second study, the 23 subjects participated in the experiment. In an experiment, we used two laboratory tasks (Go/No-Go task and delay discounting task) and neuropsychological tests (Wisconsin Card Sorting Test, Tower of Hanoi and Operation Span Task) to measure aspects of impulsivity and executive function. Results of this study suggested that impulsivity is associated with a decreased ability to alter choice behavior while functioning adaptively

    ネガティブナ ハンスウ ケイコウ ト イカリ ノ カンレン : イカリ ノ ニンチ カンジョウ コウドウ ニ カンスル ケントウ

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    The purpose of this study was to examine the relationship between the negative rumination trait (NRT) and anger expression as well as examining an influence of the NRT on cognitive and emotional aspects of anger in anger provoking situation. In the experiment, the 18 participants were male undergraduate students. The NRT scale was used to assess the NRT. The participants were divided into two groups (high NRT, low NRT) based on each participants’ score of the NRT scale. An anger provoking situation which was a recorded conversation was presented to the participants. Then, state anger levels and automatic thoughts were measured during anger provoking situations. Results of this study showed that no difference of anger expression and state anger reduced significantly during rumination regardless of high or low NRT. Moreover, automatic thoughts in the anger provoking situations were analyzed using text mining. Result of text mining indicated that the low NRT group judged the situation in an objective perspective. In contrast, the high NRT group set up automatic thoughts about induced-anger and judgments on their situations. From these results, while there was no difference in the duration of state anger, it was suggested that participants had potential to ruminate in cognitive aspects

    Boolean Gröbner bases

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    In recent years, Boolean Gröbner bases have attracted the attention of many researchers, mainly in connection with cryptography. Several sophisticated methods have been developed for the computation of Boolean Gröbner bases. However, most of them only deal with Boolean polynomial rings over the simplest coefficient Boolean ring View the MathML source. Boolean Gröbner bases for arbitrary coefficient Boolean rings were first introduced by two of the authors almost two decades ago. While the work is not well-known among computer algebra researchers, recent active work on Boolean Gröbner bases inspired us to return to their development. In this paper, we introduce our work on Boolean Gröbner bases with arbitrary coefficient Boolean rings

    Phylogenetic Analysis of Vpx/Vpr Expression

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    Viruses of human immunodeficiency virus type 2 (HIV-2) and some simian immunodeficiency virus (SIV) lineages carry a unique accessory protein called Vpx. Vpx is essential or critical for viral replication in natural target cells such as macrophages and T lymphocytes. We have previously shown that a poly-proline motif (PPM) located at the C-terminal region of Vpx is required for its efficient expression in two strains of HIV-2 and SIVmac, and that the Vpx expression levels of the two clones are significantly different. Notably, the PPM sequence is conserved and confined to Vpx and Vpr proteins derived from certain lineages of HIV-2/SIVs. In this study, Vpx/Vpr proteins from diverse primate lentiviral lineages were experimentally and phylogenetically analyzed to obtain the general expression picture in cells. While both the level and PPM-dependency of Vpx/Vpr expression in transfected cells varied among viral strains, each viral group, based on Vpx/Vpr amino acid sequences, was found to exhibit a characteristic expression profile. Moreover, phylogenetic tree analyses on Gag and Vpx/Vpr proteins gave essentially the same results. Taken together, our study described here suggests that each primate lentiviral lineage may have developed a unique expression pattern of Vpx/Vpr proteins for adaptation to its hostile cellular and species environments in the process of viral evolution

    ジョシ ダイガクセイ ニオケル ハハムスメ カンケイ ガ ムスメ ノ ジソン カンジョウ ト ヨクウツ ニ アタエル エイキョウ

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    The purpose of this study is to investigate the relationship between daughter’s self-esteem and depression, and mother-daughter relationship of college women. It is closely related to self-esteem and parent-child relationships. A mother-daughter relationship is kept close spanning over a lifetime and the relationship variously affects both mother and daughter. In addition, depression is common in young women. College students are in an age in which change occurs in the relationship with the parent and it is a period in time when they are exposed to various stimuli prompting changes. As a result, it is presumed that depression in college women is likely increase. Results from this study reveal, daughters who have built a close relationship with the mother, have significantly higher self-esteem and lower depression than that of the daughters who do not have a close relationship .Additionally, daughters who live with their mother and are annoyed with their mother have lower self-esteem than daughters who do not live with their mother
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