Much of what we understand about heterochromatin formation in mammals has been extrapolated from forward genetic screens for modifiers of position‐effect variegation (PEV) in the fruit fly Drosophila melanogaster. The recent identification of the HUSH (Human Silencing Hub) complex suggests that more recent evolutionary developments contribute to the mechanisms underlying PEV in human cells. Although HUSH‐mediated repression also involves heterochromatin spreading through the reading and writing of the repressive H3K9me3 histone modification, clear orthologues of HUSH subunits are (...) not found in Drosophila but are conserved in vertebrates. Here we compare the insights into the mechanisms of PEV derived from genetic screens in the fly, the mouse and in human cells, review what is currently known about the HUSH complex and discuss the implications of HUSH‐mediated silencing for viral latency. Future studies will provide mechanistic insight into HUSH complex function and reveal the relationship between HUSH and other epigenetic silencing complexes. (shrink)

Variegated phenotypes often result from chromosomal rearrangements that place euchromatic genes next to heterochromatin. In such rearrangements, the condensed structure of heterochromatin can spread into euchromatic regions, which then assume the morphology of heterochromatin and become transcriptionally inactive. In position‐effect variegation (PEV) therefore, gene inactivation results from a change in chromatin structure. PEV has been intensively investigated in the fruitfly Drosophila, where the phenomenon allows a genetic dissection of chromatin components. Consequently, many genes have been identified which, (...) when mutated, act as dominant modifiers (suppressors or enhancers) of PEV. Data available already demonstrate that genetic, molecular and developmental analysis of these genes provides an avenue to the identification of regulatory and structural chromatin components, and hence to fundamental aspects of chromosome structure and function. (shrink)

Classically, position effect variegation has been studied in Drosophila and results when a euchromatic gene is placed adjacent to either centromeric heterochromatin or to a telomeric domain. In such a circumstance expression of the locus variegates, being active in some cells and silent in others. Over the last few years a comparable phenomenon in yeast has been discovered. This system promises to tell us much about this curious behaviour. Indeed, experiments reported recently(1) indicate that the variegation (...) of a yeast telomeric gene is cell‐cycle regulated. The results suggest the following model. During DNA replication there is a disassembly of chromatin that allows a competition between silencing factors and trans‐activators to take place. Thus, reassembly of the domain may result in either the repression or the expression of the affected gene and, hence, produce a variegating phenotype. (shrink)

Many loci in Drosophila exhibit dosage effects on single phenotypes. In the case of modifiers of position‐effect variegation, increases and decreases in dosage can have opposite effects on variegating phenotypes. This is seemingly paradoxical: if each locus encodes a limiting gene product sensitive to dosage decreases, then increasing the dosage of any one should have no effect, because the others should remain limiting. An earlier model put forward to resolve this paradox suggested that dosage‐dependent modifiers encode (...) protein subunits of a macromolecular complex that is sensitive to mass action equilibrium conditions. Because chemical equilibria are dynamic, however, such hypothetical complexes will be unstable to an extent that is inconsistent with the known properties of molecules that make up chromatin. An alternative model accounts for the dosage effects in terms of interactions between structural proteins that bind at multiple linked sites. These might include indirect interactions occurring between regulatory proteins and genes for structural proteins or their protein products. The large number of direct and inverse regulatory genes which are known to exist in Drosophila could account for the apparent genetic complexity that is seen for modifiers of position‐effect variegation and for other systems of phenotypic modification. (shrink)

The formation of a highly condensed chromosome structure (heterochromatin) in a region of a eukaryotic chromosome can inactivate the genes within that region. Genetic studies using the fruitfly Drosophila melanogaster have identified several essential genes which influence the formation of heterochromatin. My purpose in this review is to summarize some recent work on the genetics of heterochromatin assembly in Drosophila and a recent model for how chromosomal proteins may interact to form a heterochromatic structure.

No research explored intellectual capital about green innovation or environmental management. This study wanted to fill this research gap, and proposed a novel construct – green intellectual capital – to explore the positive relationship between green intellectual capital and competitive advantages of firms. The empirical results of this study showed that the three types of green intellectual capital – green human capital, green structural capital, and green relational capital – had positive effects on competitive advantages of firms. Moreover, this study (...) found that green relational capital was the most common among these three types of green intellectual capital, and the three types of green intellectual capital of Medium & Small Enterprises (SMEs) were all significantly less than those of large enterprises in the information and electronics industry in Taiwan. In sum, companies investing many resources and efforts in green intellectual capital could not only meet the trends of strict international environmental regulations and popular environmental consciousness of consumers, but also eventually obtain corporate competitive advantages. (shrink)

No research explored intellectual capital about green innovation or environmental management. This study wanted to fill this research gap, and proposed a novel construct - green intellectual capital - to explore the positive relationship between green intellectual capital and competitive advantages of firms. The empirical results of this study showed that the three types of green intellectual capital - green human capital, green structural capital, and green relational capital - had positive effects on competitive advantages of firms. Moreover, this study (...) found that green relational capital was the most common among these three types of green intellectual capital, and the three types of green intellectual capital of Medium & Small Enterprises were all significantly less than those of large enterprises in the information and electronics industry in Taiwan. In sum, companies investing many resources and efforts in green intellectual capital could not only meet the trends of strict international environmental regulations and popular environmental consciousness of consumers, but also eventually obtain corporate competitive advantages. (shrink)

Prosocial cartoon is characterized by helping others solve difficulties, including helping, donating, sharing, comforting, and cooperating. The current study examined whether viewing a prosocial cartoon decreases aggression immediately upon exposure and the potential mediating role of aggressive motivation. Participants involve 168 children nominated by teachers as aggressive from three Chinese kindergartens. Children in the treatment group watched a prosocial cartoon, while children in the control group watched a nonprosocial cartoon. Afterward, the Hot Sauce Task was employed to assess aggressive behavior, (...) and Aggressive Motivation Questionnaire was employed to assess aggressive motivation. Results revealed that viewing a prosocial cartoon did reduce children’s aggression immediately upon exposure. Specifically, males showed less aggressive behavior than females upon prosocial cartoon exposure, while males showed more aggressive behavior than females upon nonprosocial cartoon exposure. Mediational analysis suggested that the prosocial cartoon effect on aggression was partially mediated by aggressive motivation, especially for males. Consistent with general aggression model, findings of the study indicated that short-term exposure to a prosocial cartoon decreased children’s aggression by reducing aggressive motivation. (shrink)

Use of videogames (VGs) is almost ubiquitous in preadolescents’ and adolescents’everyday life. One of the most intriguing research topic about positive effects of VG use is about the domain of visuospatial competencies. Previous research show that training with videogames enables children and adolescents to improve their scores in visuospatial tests (such as mental rotation of shapes and cubes), and that such training could overcome gender differences in these domains. Our study aimed at (1) verifying the positive effects of videogame use (...) in the visuospatial domain both for male and female adolescents and preadolescents and (2) verifying whether the visualization style (2D or isometric 3D) of the VG has an influence about the positive effects of gaming. Six measures of visuospatial competency were administered to 318 preadolescents (mean of age = 13.94 years, range 10-18) prior and after a 3-day training with 2D and 3D Tetris. Results indicate that (1) gaming on the whole has slight positive effects both for males and females in enhancing visuospatial competencies, at least in the short term, and (2) it seems that participants who used the videogame with 2D graphics obtained greater improvements in the mental rotation domain while the participants who used the videogame with 3D gobtained greater improvements in the spatial visualization domain. However, a general learning effect between T1 and T2 was measured, which was found regardless of Experimental condition, indicating that the effect of training with videogames can be less relevant than expected. (shrink)

Recently, the Dimension Problem for effective Hausdorff dimension was solved by J. Miller in [14], where the author constructs a Turing degree of non-integral Hausdorff dimension. In this article we settle the Dimension Problem for effective packing dimension by constructing a real of strictly positive effective packing dimension that does not compute a real of effective packing dimension one (on the other hand, it is known via [10, 3, 7] that every real of strictly positive effective Hausdorff dimension computes reals (...) whose effective packing dimensions are arbitrarily close to, but not necessarily equal to, one). (shrink)

The use of Drosophila chromosomal rearrangements and transposon constructs involving the white gene reveals the existence of repressive chromatin domains that can spread over considerable genomic distances. One such type of domain is found in heterochromatin and is responsible for classical position‐effect variegation. Another type of repressive domain is established, beginning at specific sequences, by complexes of Polycomb Group proteins. Such complexes, which normally regulate the expression of many genes, including the homeotic loci, are responsible for silencing, (...) white gene variegation, pairing‐dependent effects and insertional targeting. (shrink)

Numerous genes contain regulatory elements located many tens of kilobases away from the promoter they control. Specific mechanisms must be required to ensure that such distant elements can find and interact with their proper targets but not with extraneous genes. This review explores the connections between transvection phenomena, the activation of domains of homeotic gene expression, position effect variegation and silencers. These various examples of long‐distance effects suggest that, in all cases, related forms of chromatin packaging may (...) be involved. (shrink)

In order to judge how behavior caused by the positivity effect should be considered, comparisons were made between the positivity effect and two mental disorders. These disorders, Tourette’s syndrome and psychopathy, were selected due to their extreme differences in what Strawsonian attitudes they inspire and how they are perceived relative to disordered patients’ will. Disorder-affected behavior of Tourette’s patients inspires the objective attitude and is seen as a condition affecting an individual’s will, while disorder-affected behavior of psychopaths inspires (...) the interpersonal attitude and is seen as a character trait. Relevant distinctions between psychopathy and Tourette’s syndrome were found to include their neurological causes, the obviousness of the suffering they caused, and how easily their disorder-affected behavior could be mapped onto goal-seeking behavior. These considerations suggest the positivity effect should be viewed similarly to psychopathy in terms of responsibility, although this is complicated by its time of development and other factors. (shrink)

We contribute to the empirical debate on whether we understand and predict mental states by using simulation (simulation theory) or by relying on a folk psychological theory (theory theory). To decide between these two fundamental positions, it has been argued that failure to predict other people’s choices would be challenging evidence against the simulation view. We test the specific claim that people prefer the rightmost position in choosing among equally valued objects, and whether or not this position bias (...) can be correctly predicted. A series of experiments shows that the bias appears only in a specific spatial arrangement and that it can be correctly predicted given adequate imaginative input. In concert with other recent findings on the correct prediction of choices these findings do actually strengthen, rather than challenge, the simulation account on the prediction of mental states. (shrink)

So far researchers have regarded performance appraisal feedback as desirable and have examined feed back issues assuming that feedback is actually provided. The purpose of this article is to investigate whether there is any positive effect of offering no performance appraisal feedback. We studied if the inflated expec tation of employees' own performance appraisal affects the performance of the employee positively when the feedback is held back. The empirical results indicated that expectation was positively inflated and it made significant (...) contributions to compliance with supervisor, job satisfaction and organizational commit ment. The results also showed that expectation of their supervisors' rating is a more significant indicator than the real appraisal rating itself in reviewing some employee attitudes like compliance with supervisor and organizational commitment. Several theoretical and managerial implications of the findings, including the importance of cultural difference, were also discussed. (shrink)

We contribute to the empirical debate on whether we understand and predict mental states by using simulation (simulation theory) or by relying on a folk psychological theory (theory theory). To decide between these two fundamental positions, it has been argued that failure to predict other people's choices would be challenging evidence against the simulation view. We test the specific claim that people prefer the rightmost position in choosing among equally valued objects, and whether or not this position bias (...) can be correctly predicted. A series of experiments shows that the bias appears only in a specific spatial arrangement and that it can be correctly predicted given adequate imaginative input. In concert with other recent findings on the correct prediction of choices these findings do actually strengthen, rather than challenge, the simulation account on the prediction of mental states. (shrink)