The Betti poset in monomial resolutions

Let $P$ be a finite partially ordered set with unique minimal element $\hat{0}$. We study the Betti poset of $P$, created by deleting elements $q\in P$ for which the open interval $(\hat{0}, q)$ is acyclic. Using basic simplicial topology, we demonstrate an isomorphism in homology between open intervals of the form $(\hat{0},p)\subset P$ and corresponding open intervals in the Betti poset. Our motivating application is that the Betti poset of a monomial ideal's lcm-lattice encodes both its $\mathbb{Z}^{d}$-graded Betti numbers and the structure of its minimal free resolution. In the case of rigid monomial ideals, we use the data of the Betti poset to explicitly construct the minimal free resolution. Subsequently, we introduce the notion of rigid deformation, a generalization of Bayer, Peeva, and Sturmfels' generic deformation

Retrieval of episodic versus generic information: Does the order of recall affect the amount and accuracy of details reported by children about repeated events?

Children (N = 157) 4- to 8-years old participated 1 (single) or 4 times (repeated) in an interactive event. Across each condition, half were questioned a week later about the only or a specific occurrence of the event (Depth-first), and then about what usually happens. Half were prompted in the reverse order (Breadth-first). Children with repeated experience who first were asked about what usually happens reported more event-related information overall than those asked about an occurrence first. All children used episodic language when describing an occurrence; however children with repeated-event experience used episodic language less often when describing what usually happens than did those with single experience. Accuracy rates did not differ between conditions. Implications for theories of repeated-event memory are discussed

Children’s ability to recall unique aspects of one occurrence of a repeated event

Preschool and school-age children’s memory and source monitoring were investigated by questioning them about one occurrence of a repeated lab event (n = 39). Each of the four occurrences had the same structure, but with varying alternatives for the specific activities and items presented. Variable details had a different alternative each time; hi/lo details presented the identical alternative three times and changed once. New details were present in one occurrence only and thus had no alternatives. Children more often confused variable, lo, and new details across occurrences than hi details. The 4- to 5-year-oldchildren were less accurate than 7- to 8-year-old children at attributing details to the correct occurrence when specifically asked. Younger children rarely recalled new details spontaneously, whereas 50% of the older children did and were above chance at attributing them to their correct occurrence. Results are discussed with reference to script theory, fuzzy-trace theory and the source-monitoring framework

Sources of Unreliable Testimony from Children

We distilled research findings on sources of unreliable testimony from children into four principles that capture how the field of forensic developmental psychology conceptualizes this topic. The studies selected to illustrate these principles address three major questions: (a) how do young children perform in eyewitness studies, (b) why are some children less accurate than others, and (c) what phenomena generate unreliable testimony? Throughout our research, our focus is on factors other than lying that produce inaccurate or seemingly inconsistent autobiographical reports.Collectively, this research has shown that (a) children’s eyewitness accuracy is highly dependent on context, (b) neurological immaturity makes children vulnerable to errors under some circumstances, and (c) some children are more swayed by external influences than others. Finally, the diversity of factors that can influence the reliability of children’s testimony dictates that (d) analyzing children’s testimony as if they were adults (i.e., with adult abilities, sensibilities, and motivations) will lead to frequent misunderstandings. It takes considerable knowledge of development—including information about developmental psycholinguistics, memory development, and the gradual emergence of cognitive control—to work with child witnesses and to analyze cases as there are many sources of unreliable testimony

Social Jealousy and Stigma: Negative Externalities of Social Assistance Payments in Germany

This paper examines the role of social assistance payments (SAP or Sozialhilfe) in determining levels of life satisfaction in Germany using the SOEP 1995–2004. We find strong evidence that individuals in Germany are negatively influenced by increased SAP payments controlling for income, whether or not they actually receive such payments (stigma and social jealousy). While there are obvious benefits to making SAP to those needy, there are substantial negative externalities experienced by those who neither receive SAP nor qualify (counterfactual SAP). Furthermore, these negative effects are even stronger for those who do receive benefits (stigma) suggesting that social jealousy and stigma are a force to be reckoned with when evaluating social policy.We show that the added benefits of increasing SAP are reduced by 50 to 100% because of social jealousy and stigma costs, whereas child benefits (Kindergeld) are seen to enhance life satisfaction over and above a simple income effect. Further, own-earned income, over and above the SAP subsistence level is valued much higher than transfer payments at the SAP subsistence level, suggesting a policy focus on increasing employment integration efforts for SAP recipients as opposed merely to providing SAP transfers.Well being, life satisfaction, social assistance, stigma, social jealousy

You’re Fired! The Causal Negative Effect of Unemployment on Life Satisfaction

This paper examines the impact of unemployment on life satisfaction for Germany 1984–2006, using a sample of men and women from the German Socio- Economic Panel (SOEP). Across the board we find large significant negative effects for unemployment on life satisfaction.This paper expands on previous cornerstone research from Winkelmann and Winkelmann (1998) and explicitly identifies truly exogenous unemployment entries starting from 1991.We find that for women in East andWest Germany, company closures in the year of entry into unemployment produce strongly negative effects on life satisfaction over and above an overall effect of unemployment, providing prima facie evidence of a reduced outside work option, large investments in firm-specific human capital or a family constraint. The compensating variation in terms of income is dramatic, indicating enormous non-pecuniary negative effects of exogenous unemployment due to company closures.Unemployment, life satisfaction, company closing, gender

The Impact of Private Equity Ownership on Corporate Tax Avoidance

This study investigates whether private equity (PE) firms influence the tax practices of their portfolio firms. Prior research documents that PE firms create economic value in portfolio firms through effective governance, financial, and operational engineering. Given PE firms' focus on value creation, we examine whether PE firms influence the extent and types of tax avoidance at portfolio firms as an additional source of economic value. We document that PE-backed portfolio firms engage in significantly more nonconforming tax planning and have lower marginal tax rates than other private firms. Moreover, we document that PE-backed portfolio firms pay 14.2 percent less income tax per dollar of pre-tax income than non-PE backed firms, after controlling for NOLs and debt tax shields. We find additional tax savings for PE-backed portfolio firms that are either majority-owned or owned by large PE firms, consistent with PE ownership stake, expertise, and resources serving as important factors in the tax practices of portfolio firms. We infer that PE firms view tax planning as an additional source of economic value in their portfolio firms, where the benefits outweigh any potential reputational costs associated with corporate tax avoidance.Private equity, ownership structure, tax avoidance, tax planning, tax aggressiveness, book-tax differences.

Interviewing Children about a Repeated Event: Does Prior Practice in Describing a Specific Instance of an Unrelated Repeated Event Improve the Amount and Quality of Elicited Information?

Five- to 6- and 7- to 8-year old (N=118) participated, in groups, in 4 sessions of the Laurier Activities over a 2-week period. The Laurier Activities centered around tasks such as listening to a story, completing a puzzle, mild physical exercise, relaxation, getting refreshed, and getting a surprise. Across sessions of these activities, instantiations of each task (e.g., the content of the story) were presented at different frequencies. Instantiations were fixed (the same every time), variable (changed every time), or “Hi/Lo” (the Hi frequency instantiation presented at 3 sessions, the Lo frequency instantiation presented at 1 session). Children were interviewed individually based on the NICHD protocol (Orbach et al., 2000) after a week delay. This protocol consists of rapport-building, ground rules, a practice phase in which the child is encouraged to report episodic details in response to open-ended questions, and a substantive phase. The current study focused on the Practice Phase of this interview and manipulated the type of practice in 3 between-subject conditions. In the experimental conditions, children practiced describing specific instances of a repeated autobiographical event (incident-specific practice), or what generally happens during the repeated event (general practice). Children in teh control condition described a single-experience, novel, event. Incident-specific practice benefited children most when recalling the Laurier Activities by encouraging them to disclose multiple incidents earlier, to recall more details, and to mention more differences among occurrences. Age by condition interactions suggested, however, that incident-specific practice led to a larger increase in performance over other conditions for younger children, while older children tended not to differ significantly across conditions on many variables of interest. Differences in accuracy across conditions were not significant for either age group. Findings are discussed in terms of practical implications for field interviewers

The breakdown flash of Silicon Avalance Photodiodes - backdoor for eavesdropper attacks?

Silicon avalanche photodiodes are the most sensitive photodetectors in the visible to near infrared region. However, when they are used for single photon detection in a Geiger mode, they are known to emit light on the controlled breakdown used to detect a photoelectron. This fluorescence light might have serious impacts on experimental applications like quantum cryptography or single-particle spectroscopy. We characterized the fluorescence behaviour of silicon avalanche photodiodes in the experimentally simple passive quenching configuration and discuss implications for their use in quantum cryptography systems.Comment: 9 pages, 6 figures, submitted to J. Mod. Optic