411 research outputs found

    Bulk Power Grid Risk Analysis: Ranking Infrastructure Elements According to their Risk Significance

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    Disruptions in the bulk power grid can result in very diverse consequences that include economic, social, physical, and psychological impacts. In addition, power outages do not affect all end-users of the system in the same manner. For these reasons, a risk analysis of bulk power systems requires more than determining the likelihood and magnitude of power outages; it must also include the diverse impacts power outages have on the users of the system. We propose a methodology for performing a risk analysis on the bulk power system. A power flow simulation model is used to determine the likelihood and extent of power outages when components within the system fail to perform their designed function. The consequences associated with these failures are determined by looking at the type and number of customers affected. Stakeholder input is used to evaluate the relative importance of these consequences. The methodology culminates with a ranking of each system component by its risk significance to the stakeholders. The analysis is performed for failures of infrastructure elements due to both random causes and malevolent acts

    Stepfamily Relationship Quality and Children’s Internalizing and Externalizing Problems

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    The stepfamily literature is replete with between-group analyses by which youth residing in stepfamilies are compared to youth in other family structures across indicators of adjustment and well-being. Few longitudinal studies examine variation in stepfamily functioning to identify factors that promote the positive adjustment of stepchildren over time. Using a longitudinal sample of 191 stepchildren (56% female, mean age = 11.3 years), the current study examines the association between the relationship quality of three central stepfamily dyads (stepparent–child, parent–child, and stepcouple) and children's internalizing and externalizing problems concurrently and over time. Results from path analyses indicate that higher levels of parent–child affective quality are associated with lower levels of children's concurrent internalizing and externalizing problems at Wave 1. Higher levels of stepparent–child affective quality are associated with decreases in children's internalizing and externalizing problems at Wave 2 (6 months beyond baseline), even after controlling for children's internalizing and externalizing problems at Wave 1 and other covariates. The stepcouple relationship was not directly linked to youth outcomes. Our findings provide implications for future research and practice

    An empirical analysis of the nine Internet Gaming Disorder criteria

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    Internet Gaming Disorder (IGD) has received increased scientific attention since May 2013, and its assessment can be conducted using the nine criteria suggested by American Psychiatric Association (APA). This study examined the role of each IGD criterion using a conditional inference tree model. Methods: A total of 3,377 gamers (82.7% male, mean age 20 years, SD = 4.3 years) were recruited to the present study. In addition to collecting sociodemographic information, participants filled out the Internet Gaming Disorder Scale–Short-Form (IGDS9-SF) based on the DSM-5 criteria. Results: The conditional inference tree model revealed that endorsement of ‘withdrawal’ (criterion 2) and ‘loss of control’ (criterion 4) increased the likelihood of IGD by 77.77% (95%CI: 62.09–93.45) while endorsing ‘withdrawal’, ‘loss of control’ and ‘negative consequences’ (criterion 9) increased the likelihood of IGD by 26.66% (95%CI: 4.28–49.04). Finally, not endorsing ‘withdrawal’ but endorsing ‘preoccupation’ (criterion 1) increased the probability of IGD by 7.14% (95%CI: 1.63–12.65). Conclusions: Overall, these results suggest that not all IGD criteria carry the same diagnostic weight as each criterion can play a different role in the development of IGD. It is envisaged that these findings will help improve the assessment of IGD in the future

    Two-dimensional superconductivity at a Mott-Insulator/Band-Insulator interface: LaTiO3/SrTiO3

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    Transition metal oxides display a great variety of quantum electronic behaviours where correlations often play an important role. The achievement of high quality epitaxial interfaces involving such materials gives a unique opportunity to engineer artificial structures where new electronic orders take place. One of the most striking result in this area is the recent observation of a two-dimensional electron gas at the interface between a strongly correlated Mott insulator LaTiO3 and a band insulator SrTiO3. The mechanism responsible for such a behaviour is still under debate. In particular, the influence of the nature of the insulator has to be clarified. Here we show that despite the expected electronic correlations, LaTiO3/SrTiO3 heterostructures undergo a superconducting transition at a critical temperature Tc=300 mK. We have found that the superconducting electron gas is confined over a typical thickness of 12 nm. We discuss the electronic properties of this system and review the possible scenarios

    Tuning of metal-insulator transition of two-dimensional electrons at parylene/SrTiO3_3 interface by electric field

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    Electrostatic carrier doping using a field-effect-transistor structure is an intriguing approach to explore electronic phases by critical control of carrier concentration. We demonstrate the reversible control of the insulator-metal transition (IMT) in a two dimensional (2D) electron gas at the interface of insulating SrTiO3_3 single crystals. Superconductivity was observed in a limited number of devices doped far beyond the IMT, which may imply the presence of 2D metal-superconductor transition. This realization of a two-dimensional metallic state on the most widely-used perovskite oxide is the best manifestation of the potential of oxide electronics

    Dynein structure and power stroke

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    Dynein ATPases are microtubule motors that are critical to diverse processes such as vesicle transport and the beating of sperm tails; however, their mechanism of force generation is unknown. Each dynein comprises a head, from which a stalk and a stem emerge. Here we use electron microscopy and image processing to reveal new structural details of dynein c, an isoform from Chlamydomonas reinhardtii flagella, at the start and end of its power stroke. Both stem and stalk are flexible, and the stem connects to the head by means of a linker approximately 10 nm long that we propose lies across the head. With both ADP and vanadate bound, the stem and stalk emerge from the head 10 nm apart. However, without nucleotide they emerge much closer together owing to a change in linker orientation, and the coiled-coil stalk becomes stiffer. The net result is a shortening of the molecule coupled to an approximately 15-nm displacement of the tip of the stalk. These changes indicate a mechanism for the dynein power stroke

    Does Marital Status of Parents Relate to Family Communication Regarding Finances?

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    How do youth and parents perceive their communication with each other? How do they perceive communication about money with each other? Are there differences between married-parent families and single-parent families? The reported study examined the discrepancies in perception between parents and youth and compares these differences between married and single-parent families. Although single-parent families had greater discrepancies in perceptions regarding communication in general, there was no evidence of such differences in discrepancies regarding communication about money. The finding suggests the importance of youth development programs to provide information and encouragement to both youth and their parents
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