Effect of embedded voltage source converter on power system oscillation damping

This paper presents the damping torque analysis of power system oscillation stability as affected by the dynamic and control functions of an embedded voltage source converter(VSC).The objective of the study is to explain why and how the dynamic and basic control functions of the embedded VSC,ac and dc voltage regulation,provide damping to power system oscillations.The most important conclusion obtained in the paper is that both the dynamics and the dc voltage control of the VSC contribute a variable damping...     

Validation of a brief measure of posttraumatic stress disorder: The Distressing Event Questionnaire (DEQ).

The Distressing Event Questionnaire (DEQ) is a brief instrument for assessing posttraumatic stress disorder (PTSD) according to criteria provided in Diagnostic and Statistical Manual of Mental Disorders (4th ed.). The DEQ possesses high internal consistency and exhibited satisfactory short-term temporal stability in studies with Vietnam War combat veterans and battered women. In a sample of Vietnam War veterans and 4 separate samples of abused women (with histories of incest, rape, intimate partner abuse, or prostitution and abuse), the DEQ exhibited very good discriminative validity when judged against structured interview assessment of PTSD. The DEQ exhibited strong convergent validity with other PTSD measures and other indexes of adjustment and also exhibited strong convergent validity as a measure of PTSD across ethnic groups in both the veteran sample and the combined women's sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Representation-theoretical properties of the approximate quantum Fourier transform

Among the transformations used in quantum computing the discrete Fourier transform (DFT) plays a key role. A striking fact is that the computational complexity of the DFT with respect to the quantum gate model is polylogarithmic in the length of the input data. In this paper we consider approximate Fourier transformations which are obtained by pruning the twiddle factors of DFT. A parameter is used which determines the level of pruning. The extreme cases are no pruning, which leads to the DFT, and complete pruning, which leads to the Hadamard transform. Our main result is to give a representation-theoretical interpretation of the transformation obtained for all intermediate levels of pruning. We show that the resulting approximate quantum Fourier transforms are basefield transformations, i. e., they decompose the regular representation of the cyclic group over non-splitting fields. Thomas Beth passed away on August 17, 2005. The results presented here had been obtained in joint work with him and had been included into the first author’s Ph.D. thesis. These results have not been published yet.     

Old Communication, New Literacies: Social Network Sites as Social Learning Resources

This study examined the role of a social network site (SNS) in the lives of 11 high school teenagers from low-income families in the U.S. We conducted interviews, talk-alouds and content analysis of MySpace profiles. Qualitative analysis of these data revealed three themes. First, SNSs facilitated emotional support, helped maintain relationships, and provided a platform for self-presentation. Second, students used their online social network to fulfill essential social learning functions. Third, within their SNS, students engaged in a complex array of communicative and creative endeavors. In several instances, students' use of social network sites demonstrated the new literacy practices currently being discussed within education reform efforts. Based on our findings, we suggest additional directions for related research and educational practices.     

Treatment of peripheral vascular disease with stent-grafts

To evaluate renal function after the use of a low-osmolality radiological contrast medium (CM), we prospectively analyzed 39 patients submitted to the following examinations: arteriography (n = 32), phlebography (n = 3), computed tomography (n = 3), angioplasty (n = 1), and retrograde pyelography (n = 1). The patients were divided into three groups: group 1, control, formed by renal donors (CT, n = 11 and 11 exams); group 2, hypertensive patients (HYPT, n = 15 and 16 exams); and group 3, patients with diseases of multiple etiologies (MIX, n = 13 patients and 13 exams). Additionally, the patients were divided according to their renal function into: group 4, with a moderate deficit of renal function, creatinine clearance (CrCl) 25 to 60 mL/min (n = 15 patients and 15 exams); and group 5, with a mild deficit of renal function, CrCl > or = 60 mL/min (n = 14 patients and 14 exams). The CM utilized was ioxaglic acid (Hexabrix) the incidence of acute renal failure (ARF) among the patients studied was 12.5% (5/40), and CrCl was the best parameter to monitor the alterations in renal function, which occurred in 35% of the patients, although the changes were mild, reversible, and did not need any therapeutic interventions. The triggering of ARF in these patients may have been due to multiple factors presented at time of CM examination. Thus, it is not possible to identify a single risk factor. However, it is probable that previous important impairment of renal function was the most expressive risk factor.     

Vicarious traumatization, spirituality, and the treatment of sexual abuse survivors: A national survey of women psychotherapists.

Should psychotherapists limit their clinical work with trauma survivors to avoid being traumatized themselves? Vicarious traumatization (VT—the symptoms similar to posttraumatic stress disorder and the disruption in cognitive schemas reported in clinicians who are exposed to the trauma material of their clients—was assessed in a national survey of 1,000 women psychotherapists. Therapists with higher levels of exposure to sexual abuse material reported significantly more trauma symptoms but no significant disruption of cognitive schemas. Spiritual well-being, a key area thought to be damaged by VT, was found to be higher for those clinicians who saw more sexual abuse survivors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quitting chew: Results from a randomized trial using nicotine patches.

The authors examined the efficacy of transdermal nicotine replacement for cessation in 410 adult nonsmoking chewing tobacco users. Participants were randomly assigned to 6 weeks of 15-mg nicotine patch plus behavioral treatment or placebo patch plus behavioral treatment. All participants received the same behavioral treatment of 2 pharmacy visits, 2 support calls, and self-help materials. At 6 months after treatment, biochemically confirmed point-prevalence rates (no chewing in the last 7 days) in the active (38%) and placebo (34%) groups were high and not significantly different. The difference in relapse (no chewing for 7 consecutive days) between the active patch group (33%) and placebo group (48%) was significant at 6 months (p?=?.003). Nicotine dependence and age predicted nonrelapse at 6 months. The results suggest that nicotine replacement may improve chewers' chances of abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The state of public-key cryptography - not only after the invention of quantum computers

When in August 1994 Peter Shor first presented his renowned algorithm for factoring large numbers on a quantum computer in polynomial time, most security experts around the world initially were seized with dismay. The consequences for modern cryptographic technology and practically all applications ranging from Internet communications to digital signature authentication, at first glance seemed to be fatal. However, a careful analysis of the situation carried out by some of the responsible researchers in cryptology, especially those experts with a long-standing experience in cryptanalysis, has shown that this situation is not as simple and has to be evaluated not only cum grano salis but also cum grano capitis: as usual in our field of crypto security, a fair assessment of the situation can be made only based on detailed knowledge and some special experience in order to give advice to those who have to plan and use future security technology.     

Kappa1- and kappa2-opioid receptors mediating presynaptic inhibition of dopamine and acetylcholine release in rat neostriatum

1. The effects of selective opioid receptor agonists and antagonists on N-methyl-D-aspartate (NMDA, 10 microM)-induced release of [3H]-dopamine and [14C]-acetylcholine (ACh) from superfused neostriatal slices were studied to investigate the possible occurrence of functional kappa-opioid receptor subtypes in rat brain. 2. The kappa receptor agonists (-)-ethylketocyclazocine ((-)-EKC), U69593 and the endogenous opioid peptide dynorphin A1-13 caused a naloxone-reversible inhibition of NMDA-induced [3H]-dopamine release, with pD2 values of about 9, 8.5 and 8.2, respectively, whereas both the mu agonist Tyr-D-Ala-Gly-(NMe)Phe-Gly-ol (DAMGO) and the delta agonist D-Pen2-D-Pen5-enkephalin (DPDPE) were ineffective in this respect. The inhibitory effect of submaximally effective concentrations of dynorphin A1-13, U69593 and (-)-EKC on NMDA-induced [3H]-dopamine release were not changed by the delta1/delta2-opioid receptor antagonist naltrindole (up to a concentration of 1 microM, but reversed by the kappa receptor antagonist nor-binaltorphimine (nor-BNI), with an IC50) as low as 0.02 nM, indicating the involvement of U69593-sensitive kappa1-opioid receptors. 3. NMDA-induced [14C]-ACh release was reduced in a naloxone-reversible manner by DPDPE (pD2 about 7.2), dynorphin A1-13 (pD2 6.7) and EKC (pD2 6.2), but not by U69593 and DAMGO. The inhibitory effect of a submaximally effective concentration of DPDPE, unlike those of dynorphin A1-13 and (-)-EKC, on NMDA-induced [14C]-ACh release was antagonized by naltrindole with an IC50 of 1 nM, indicating the involvement of delta-opioid receptors in the inhibitory effect of DPDPE. On the other hand, the inhibitory effects of dynorphin A1-13 and (-)-EKC on [14C]-ACh release were readily antagonized by nor-BNI with an IC50 of about 3 nM. A 100 fold higher concentration of nor-BNI also antagonized the inhibitory effect of DPDPE, indicating the involvement of U69593-insensitive kappa2-opioid receptors in the inhibitory effects of dynorphin A1-13 and (-)-EKC. 4. Although naloxone benzoylhydrazone (NalBzoH), displaying high affinity towards the putative kappa3-opioid receptor, antagonized the inhibitory effects of dynorphin A1-13 and (-)-EKC on [3H]-dopamine and [14C]-ACh release as well as that of U69593 on [3H]-dopamine release, it displayed a low apparent affinity (IC50 about 100 nM) in each case. 5. In conclusion, whereas activation of kappa1-opioid receptors causes presynaptic inhibition of NMDA-induced dopamine release, kappa2 receptor activation results in inhibition of ACh release in rat neostriatum. As such, this study is the first to provide unequivocal in vitro evidence for the existence of functionally distinct kappa-opioid receptor subtypes in the brain.     

Sequencing and functional analysis of the SNRPN promoter: in vitro methylation abolishes promoter activity

The gene encoding the small nuclear ribonucleoprotein-associated polypeptide N (SNRPN) maps to the Prader-Willi syndrome critical region on chromosome 15 and is expressed preferentially from the paternal allele. A CpG island encompassing the first exon of SNRPN is methylated on the inactive maternal allele. DNA sequence was determined for a cosmid containing the first three exons of SNRPN and extending 20 kb upstream and 15 kb downstream from the CpG island. This region is extremely rich in Alu elements and other repetitive sequences and contains a single CpG island, which includes numerous short direct repeat sequences. Functional analysis of the first exon revealed strong promoter activity for a 260-bp fragment extending 207 bp upstream from the exon. In vitro methylation of this 260-bp fragment abolished promoter activity completely, suggesting that the silencing of the maternal SNRPN allele may be a direct consequence of methylation of the promoter region.