bluuebunny/crossref_metadata_2025 huggingface dataset:
The Golod-Shafarevich inequality for Hilbert series of quadratic algebras and the Anick conjecture
Authors: Iyudu Natalia , Shkarin Stanislav
Published: June 2011

We study the question of whether the famous Golod-Shafarevich estimate, which gives a lower bound for the Hilbert series of a (non-commutative) algebra, is attained. This question was considered by Anick in his 1983 paper, ‘Generic algebras and CW-complexes’ (Princeton University Press), where he proved that the estimate is attained for the number of quadratic relations d ≤ ¼n2 and d ≥ ½n2, and conjectured that it is the case for any number of quadratic relations. The particular point where the number of relations is equal to ½n(n – 1) was addressed by Vershik. He conjectured that a generic algebra with this number of relations is finite dimensional.

We prove that over any infinite field, the Anick conjecture holds for d ≥ (n2 + n) and an arbitrary number of generators n, and confirm the Vershik conjecture over any field of characteristic 0. We give also a series of related asymptotic results.
A THEORY OF ECONOMIC DEVELOPMENT WITH ENDOGENOUS FERTILITY
Authors: Elgin Ceyhun
Published: June 2011

In this paper I build a unified model of economic growth to account for the time-series evolution of output, fertility, and population in the industrialization of an economy. Specifically, I merge the unified growth models of Galor and Weil [American Economic Review90 (2000), 806–828] and Hansen and Prescott [American Economic Review92 (2002), 1205–1217] to capture the importance of human capital formation, fertility decline, and the transition from agriculture to industry in transition from stagnation to growth. Moreover, I also incorporate young adult mortality into the model. Initially, the aggregate human capital and return to education are low and the mortality rate is high; therefore parents invest in quantity of children. Once sufficient human capital is accumulated and mortality rates are reduced, thanks to increasing life expectancy, with the activation of the modern human capital–intensive sector, parents start to invest in the quality of their children. The simulation of the model economy improves upon the quantitative performance of the existing literature and successfully captures the evolution of fertility, population, and GDP in the British economy between 1750 and 2000.
ON THE “HOT POTATO” EFFECT OF INFLATION: INTENSIVE VERSUS EXTENSIVE MARGINS
Authors: Liu Lucy Qian , Wang Liang , Wright Randall
Published: June 2011

Conventional wisdom is that inflation makes people spend money faster, trying to get rid of it like a “hot potato,” and this is a channel through which inflation affects velocity and welfare. Monetary theory with endogenous search intensity seems ideal for studying this. However, in standard models, inflation is a tax that lowers the surplus from monetary exchange and hence reduces search effort. We replace search intensity with a free entry (participation) decision for buyers—i.e., we focus on the extensive rather than intensive margin—and prove buyers always spend their money faster when inflation increases. We also discuss welfare.
Kant on the Highest Moral-Physical Good: The Social Aspect of Kant's Moral Philosophy
Authors: Formosa Paul
Published: June 2011

In §88, entitled ‘On the highest moral-physical good’, in hisAnthropology from a Pragmatic Point of View(hereafterAnthropologyfor short), Kant argues that ‘good living’ (physical good) and ‘true humanity’ (moral good) best harmonize in a ‘good meal in good company’. The conversation and company shared over a meal, Kant argues, best provides for the ‘union of social good living with virtue’ in a way that promotes ‘true humanity’. This occurs when the inclination to ‘good living’ is not merely kept within the bounds of ‘the law of virtue’ but where the two achieve a graceful harmony. As such, it is not to be confused with Kant's well-known account of the ‘highest good’, happiness in proportion to virtue. But how is it that the humble dinner party and the associated practices of hospitality come to hold such an important, if often unrecognized, place as the highest moral-physical good in Kant's thought? This question is in need of further investigation. Of the most recent studies in English that have taken seriously the importance of Kant'sAnthropologyfor understanding his wider moral philosophy, very few have considered §88 in any depth. This paper aims to help bridge this signifcant gap in the literature.
On the Apodictic Proof and Validation of Kant's Revolutionary Hypothesis
Authors: Fulkerson-Smith Brett A.
Published: June 2011

The second edition of the Critique of Pure Reason (hereafter, Critique) contains several major and myriad minor emendations. The revision of the mode of presentation is apparent in four sections of the Critique: the Aesthetic; the Doctrine of the Concepts of the Understanding; the Principles of Pure Understanding; and ‘the paralogisms advanced against rational psychology’ (Bxxxviii). A new refutation of psychological idealism begins at B274. Perhaps most importantly, a new Preface frames the Critique.
Humanity, Obligation, and the Good Will: An Argument against Dean's Interpretation of Humanity
Authors: Denis Lara
Published: June 2011

Humanity (die Menschheit) is an important notion within Kant's moral theory. The humanity formulation of the categorical imperative (FH) commands: ‘So act that you use humanity, whether in your own person or in the person of any other, always at the same time as an end, never merely as a means’ (G 4: 429). Kant's analysis of ethical obligation and his expositions of rights and duties in the Metaphysics of Morals refer frequently to humanity. How we understand this concept, then, has signifcant implications for how we understand Kant's ethics.
The Social Science of Democracy?
Authors: Welch Cheryl
Published: June 2011

Alexis de Tocqueville, the First Social Scientist. By Jon Elster. New York: Cambridge University Press, 2009. 212p. $80.00 cloth, $22.99 paper.

Alexis de Tocqueville is surely one of the most widely cited, discussed, and celebrated political theorists in the world. Jon Elster's book, Alexis de Tocqueville: the First Social Scientist proceeds from a provocative premise: that Tocqueville's major works were lacking in “system” and were “hugely incoherent,” and that Tocqeuville himself “was not a major political thinker” (xi). Elster argues that instead Tocqueville ought to be viewed as a penetrating historical sociologist and an exemplary social scientist who might well be considered the first true social scientist. Elster's argument is important for at least two reasons: first, because it offers a striking and challenging reading of Tocqueville; and second, because it expands on Elster's own contributions in the philosophy of social science, and develops interesting understandings of “causal mechanisms,” methodological individualism, and social explanation more generally. As Elster writes in his Introduction, “the main task of this book is to argue for the relevance of Tocqueville for social science in the twenty-first century (p. 5).” The purpose of this Perspectives symposium is to assess Elster's argument in broad terms. What are the strengths and limits of Elster's reading of Tocqueville? How ought we to assess Elster's understanding of Tocqueville's deficiencies as a “political theorist?” What is the relevance of Tocqueville for contemporary social science? And, most importantly, what are the challenges and possible trajectories facing social science in the twenty-first century, and to what extent does Elster's essay point us in the right direction?—Jeffrey C. Isaac, Editor
Response to Steven Levitsky and Lucan Way's review ofOrdering Power: Contentious Politics and Authoritarian Leviathans in Southeast Asia
Authors: Slater Dan
Published: June 2011

As Steven Levitsky and Lucan Way's gracious review demonstrates, Ordering Power and Competitive Authoritarianism share much in common. Yet their two main critiques helpfully underscore how our books are also significantly dissimilar. Their skepticism about my book's generalizability highlights our divergent approaches to generalization, while their claim that revolutionary regimes are as robust as counterrevolutionary regimes reflects our different thinking about cohesion and stability.
Competitive Authoritarianism: Hybrid Regimes after the Cold War. By Steven Levitsky and Lucan A. Way. New York: Cambridge University Press, 2010. 517p. $95.00 cloth, $29.99 paper.
Authors: Slater Dan
Published: June 2011

The literature on hybrid regimes has a new and undisputed heavyweight champion. Eight years after their widely cited Journal of Democracy article first unveiled “competitive authoritarianism” as a distinctive type of hybrid regime, Steven Levitsky and Lucan Way have constructed a volume that theorizes and traces the trajectories of the countries that have fit into this category since the Cold War's end—all thirty-five of them. While the theoretical ambition of Competitive Authoritarianism stakes the book's rightful claim to the title of hybrid-regime champion, the book's voluminous empirics unmistakably place it in political science's heavyweight class.
Response to Gaston Alonso's review ofComplex Justice: The Case ofMissouri v. Jenkins
Authors: Dunn Joshua
Published: June 2011

I would like to thank Gaston Alonso for his kind review and his perceptive criticisms. We share many concerns about the state of urban education. Our differences center largely on what to do in response to the systemic failure of many urban school systems. Even here, though, I suspect that our differences are not as substantial as they first appear. While Alonso and his coauthors call for an infusion of resources into urban schools, I remain skeptical both that underfunding really is the source of their problems and that more money would be used effectively absent more fundamental reforms. But when an urban school district truly lacks sufficient resources to provide a safe and humane learning environment, then certainly more funding is called for. I would prefer that such funding be contingent on implementing additional reforms that ensure that the resources make their way to students, rather than being diverted or absorbed along the way.
Democratic Theory afterTransitions from Authoritarian Rule
Authors: Munck Gerardo L.
Published: June 2011

Recent events across the globe make clear the complexities of the politics of “democratization” and the importance of developing nuanced and compelling understandings of these complexities. In Eurasia, “Color Revolutions” have given way to democratic disappointments and “authoritarian regimes.” In north Africa, an unanticipated upsurge of democratic movements has felled autocrats in Tunisia and Egypt, but the political outcomes of these “transitions” are very much in doubt. Contemporary political science has developed an elaborate vocabulary for understanding such processes. And this vocabulary owes a great deal to a small group of scholars—Juan Linz, Guillermo O'Donnell, Philippe Schmitter, Alfred Stepan and Adam Przeworksi—who helped to lay the theoretical foundations of our current understanding of politics around the globe.
Law, Politics, and Democracy in the Twenty-first Century
Authors: Pickerill J. Mitchell
Published: June 2011

Political scientists have long rejected the old law and politics dichotomy and recognize instead that law and court decisions are inherently political in numerous ways. Still, courts are not the same as executive and legislative institutions, and law is not simply a synonym for politics or policy. Law and courts are distinct and yet connected to political processes and policy outcomes in complex and nuanced ways. The question for law and courts scholars, then, is how and why do political actors (with seemingly increasing frequency) turn to law and the judiciary to influence public policy, and what are the impacts of infusing law and courts into the US political process? The three recent books under review help to answer these questions.
Authoritarian Deliberation: The Deliberative Turn in Chinese Political Development
Authors: He Baogang , Warren Mark E.
Published: June 2011

Authoritarian rule in China is now permeated by a wide variety of deliberative practices. These practices combine authoritarian concentrations of power with deliberative influence, producing the apparent anomaly of authoritarian deliberation. Although deliberation is usually associated with democracy, they are distinct phenomena. Democracy involves the inclusion of individuals in matters that affect them through distributions of empowerments such as votes and rights. Deliberation is a mode of communication involving persuasion-based influence. Combinations of non-inclusive power and deliberative influence—authoritarian deliberation—are readily identifiable in China, probably reflecting failures of command authoritarianism under the conditions of complexity and pluralism produced by market-oriented development. The concept of authoritarian deliberation frames two possible trajectories of political development in China: the increasing use of deliberative practices stabilizes and strengthens authoritarian rule, or deliberative practices serve as a leading edge of democratization.
THE UNIVERSAL SET AND DIAGONALIZATION IN FREGE STRUCTURES
Authors: KAHLE REINHARD
Published: June 2011

In this paper we summarize some results about sets in Frege structures. The resulting set theory is discussed with respect to its historical and philosophical significance. This includes the treatment of diagonalization in the presence of a universal set.
Expression of P-selectin, von Willebrand and endothelin-1 after carotid artery stenting
Authors: Xia  , Yang  , Qu  , Cheng  , Wang
Published: June 2011

Background: This study was designed to investigate the impact of carotid artery stenting (CAS) on plasma levels of P-selectin, von Willebrand (vWF) and endothelin-1. Patients and methods: Sixty-seven patients who received CAS were divided into group 1 (one stent for a simple lesion, n = 38) and group 2 (two stents for complex lesions, n = 29). The levels of P-selectin, vWF and endothelin-1 were measured before CAS, 1 h, 6h, 24 h and 2 weeks after the stenting. Results: Sixty-one patients completed one-year follow up. Restenosis was noted in 14 (23 %) patients, among these three (4.8 %) had a restenosis of > 50 % of the vascular lumen. In all patients, the levels of P-selectin, vWF and endothelin-1 increased immediately after CAS (P < 0.05 or < 0.01). The levels of vWF and endothelin-1 in group 2 were higher than in group 1 (P < 0.05 or 0.01). There was no significant difference in P-selectin and endothelin-1 between the restenosis and non-restenosis group (P > 0.05). The 24 h vWF in patients with restenosis were higher than in non-restenosis group (P < 0.05). Conclusions: CAS results in a significant increase in plasma P-selectin, vWF and endothelin-1. The post-CAS levels of P-selectin, vWF and endothelin-1 are related to the extent of endothelial injury. Whether they are associated with restenosis 12 months after the treatment requires further investigation.
Bipolar radiofrequency induced thermotherapy and 1064 nm Nd:Yag laser in endovenous occlusion of insufficient veins: short term follow up results
Authors: Krnic  , Sucic
Published: June 2011

Background: The aim of this study is to report our results in main stem vein closure using the bipolar radiofrequency induced thermotherapy (RFITT) system and the 1064nm Nd:Yag laser. Patients and methods: 44 incompetent main stem veins (37 great saphenous veins, one lesser saphenous vein, and 6 anterior accessory saphenous veins) in 29 patients were treated using RFITT. 53 incompetent main stem veins (45 great saphenous veins, 4 lesser saphenous veins, and 4 anterior accessory saphenous veins) in 43 patients were treated endovenously with 1064 nm Nd:Yag laser. All patients underwent postoperative duplex scanning within a month after procedure, as well as a short interview regarding postoperative discomfort. Results: In main stem veins treated with RFITT, the success rate within the first month was 86,4 % (38 out of 44 veins). Complete failure rate was 13,6 % (6 out of 44 veins). In 53 main stem veins treated by 1064 nm Nd:Yag laser, the success rate was 100 %, consisting of 98,1 % complete success (52/53 veins), and 1,9 % partial success (1/53 veins). None of the patients treated with RFITT experienced postoperative adverse effects, whereas 13/43 (30,2 %) patients treated with laser had to use oral analgesics after the treatment, and 21/43 (48,8 %) patients reported transient skin changes, such as bruising or skin redness. Conclusions: RFITT system was fairly efficient in the short term for closure of main trunk veins, whereas longer term results are still scarce. Postoperative side effects of RFITT were minimal. 1064nm Nd:Yag laser, according to short term results, proved to be very effective for main stem vein closure. Postoperative side effects related to 1064 nm Nd:Yag endovenous laser treatment proved to be minor, transient, and acceptable.
Hybrid procedures for the treatment of multi-focal ipsilateral internal carotid and proximal common carotid or innominate artery lesions
Authors: Karathanos  , Sfyroeras  , Stamoulis  , Drakou  , Vretzakis  , Giannoukas
Published: June 2011

We report three cases with concomitant ipsilateral proximal common carotid and internal carotid artery stenosis treated in one stage with carotid endarterectomy and retrograde primary stenting of the common carotid artery. The internal carotid artery was clamped during stenting to avoid cerebral embolization. All procedures were successfully completed and all patients remain asymptomatic at 18 months follow up. The one-stage hybrid approach appears to be a safe and effective procedure for the treatment of ipsilateral multifocal significant lesions.
Popliteal artery thrombosis secondary to a tibial osteochondroma
Authors: Gruber-Szydlo  , Poreba  , Belowska-Bien  , Derkacz  , Badowski  , Andrzejak  , Szuba
Published: June 2011

Popliteal artery thrombosis may present as a complication of an osteochondroma located in the vicinity of the knee joint. This is a case report of a 26-year-old man with symptoms of the right lower extremity ischaemia without a previous history of vascular disease or trauma. Plain radiography, magnetic resonance angiography and Doppler ultrasonography documented the presence of an osteochondrous structure of the proximal tibial metaphysis, which displaced and compressed the popliteal artery, causing its occlusion due to intraluminal thrombosis..The patient was operated and histopathological examination confirmed the diagnosis of osteochondroma.
Kompetenzdiagnostik im Berufsfeld Pflege
Authors: Darmann-Finck Ingrid , Glissmann Gerlinde
Published: June 2011

Effizienz und Effektivität von Bildungsprogrammen im Berufsfeld Pflege lassen sich letztlich nur durch die Messung der erreichten Lernergebnisse überprüfen und vergleichen. Auf der Suche nach einem geeigneten diagnostischen Instrumentarium wurde eine umfassende Literaturrecherche zum gegenwärtigen Stand der Kompetenzdiagnostik im Berufsfeld Pflege im deutschsprachigen Raum vorgenommen. Eine ebensolche Recherche wurde in einschlägigen internationalen Fachzeitschriften durchgeführt. Die Recherchen führten zu dem Ergebnis, dass es national wie international bislang eine erhebliche Forschungslücke in der systematischen, theoretisch und empirisch fundierten Entwicklung von Instrumenten zur Diagnostik von Pflegekompetenz gibt. Abschließend werden Schlussfolgerungen für die Entwicklung von Instrumenten der Kompetenzdiagnostik gezogen.
The Predictive Validity of Assessment Centers in German-Speaking Regions
Authors: Becker Nicolas , Höft Stefan , Holzenkamp Marcus , Spinath Frank M.
Published: June 2011

As previous meta-analyses have focused almost solely on English-speaking regions, this study presents the first systematic meta-analytical examination of the predictive validity of assessment centers (ACs) conducted in German-speaking regions. It summarizes 24 validity coefficients taken from 19 studies (N = 3,556), yielding a mean corrected validity of ρ = .396 (80% credibility interval .235 ≤ ρ ≤ .558). ACs with different purposes and different kinds of criterion measures were analyzed separately. Furthermore, target group (internal vs. external candidates), average age of the assessees, inclusion of intelligence measures, number of instruments used, AC duration, as well as time elapsed between AC and criterion assessment were found to moderate the validity.
Applicant Versus Employee Scores on Self-Report Emotional Intelligence Measures
Authors: Lievens Filip , Klehe Ute-Christine , Libbrecht Nele
Published: June 2011

There exists growing interest to assess applicants’ emotional intelligence (EI) via self-report trait-based measures of EI as part of the selection process. However, some studies that experimentally manipulated applicant conditions have cautioned that in these conditions use of self-report measures for assessing EI might lead to considerably higher scores than current norm scores suggest. So far, no studies have scrutinized self-reported EI scores among a sample of actual job applicants. Therefore, this study compares the scores of actual applicants at a large ICT organization (n = 109) on a well-known self-report measure of EI to the scores of employees already working in the organization (n = 239). The current study is the first to show that applicants’ scores on a self-report measure of EI during the selection process are indeed higher (d = 1.12) and have less variance (SD ratio = 0.86/1) than incumbents’ scores. Finally, a meta-analytic combination of our results with those of earlier research showed that a score increase of about 1 SD in applicant conditions seems to be the rule, regardless of the type of setting, self-report EI measure, and within- versus between-subjects design employed.
Environmental versus biological controls on Mg/Ca variability in Globigerinoides ruber (white) from core top and plankton tow samples in the southwest Pacific Ocean
Authors: Bolton Annette , Baker Joel A. , Dunbar Gavin B. , Carter Lionel , Smith Euan G. C. , Neil Helen L.
Published: June 2011

Laser ablation inductively coupled plasma mass spectrometry was used to analyze the individual chambers from tests of foraminiferal fossil and plankton tow Globigerinoides ruber from the southwest Pacific Ocean, from latitudes 3°S to 42°S. The variability of Mg/Ca between chambers of an individual (intraindividual) and individuals of the same population (interindividual), is such that when converted to temperature, the extent of intra‐individual and interindividual variability appears to exceed that attributable to either calcification or seasonal temperature variability. The pooled mean chamber Mg/Ca from each core top and plankton tow site demonstrates a significant (p < 0.05) positive correlation with temperature. We derive chamber‐specific calibrations where Mg/CaCh_F‐2 = 0.798 exp0.070 T, Mg/CaCh_F‐1 = 0.891 exp0.067 T and Mg/CaCh_F = 0.590 exp0.072 T. We do not observe any bias between the two morphotypes Gs. ruber ruber and Gs. ruber pyramidalis. The chamber‐specific calibrations potentially offset Mg/Ca‐based temperature reconstructions if used on bulk (whole) test Mg/Ca or applied to misidentified chambers. Nevertheless, these calibrations can be used to reliably estimate sea surface temperature. Although there is a general overriding temperature control on Mg/Ca, we show that removal of the effect of temperature at each site reveals a lognormal Mg/Ca distribution. This suggests that Mg/Ca variability at each site is also affected by biological mechanism(s) that may control the distribution of interindividual Mg/Ca. In addition, other TE/Ca data (Al/Ca and Mn/Ca) from laser ablation trace element depth profiles can be used to identify detrital or diagenetic phases that may bias the trace element/Ca signal.
Coherent millennial‐scale patterns in U37k′ and TEX86H temperature records during the penultimate interglacial‐to‐glacial cycle in the western Mediterranean
Authors: Huguet Carme , Martrat Belen , Grimalt Joan O. , Sinninghe Damsté Jaap S. , Schouten Stefan
Published: June 2011

The TEX86H temperature proxy is a relatively new proxy based on crenarchaeotal lipids and has rarely been applied together with other temperature proxies. In this study, we applied the TEX86H on a sediment core from the Alboran Sea (western Mediterranean, core ODP‐977A) covering the penultimate climate cycle, that is, from 244 to 130 ka, and compared this with previously published sea surface temperatures derived from the U37k′ of alkenones of haptophyta and Mg/Ca records of planktonic foraminifera. The TEX86H temperature record shows remarkably similar stadial‐interstadial patterns and abrupt temperature changes to those observed with the U37k′ palaeothermometer. Absolute TEX86H temperature estimates are generally higher than those of U37k′, though this difference (<3°C in 81% of the data points) is mainly within the temperature calibration error for both proxies, suggesting that crenarchaeota and haptophyta experienced similar temperature variations. During occasional events (<5% of the analyzed time span), however, the TEX86H exhibits considerably higher absolute temperature estimates than the U37k′. Comparison with Mg/Ca records of planktonic foraminifera as well as other Mediterranean TEX86 and U37k′ records suggests that part of this divergence may be attributed to seasonal differences, that is, with TEX86H reflecting mainly the warm summer season while U37k′ would show annual mean. Biases in the global calibration of both proxies or specific biases in the Mediterranean are an alternative, though less likely, explanation. Despite differences between absolute TEX86H and U37k′ temperatures, the correlation between the two proxies (r2 = 0.59, 95% significance) provides support for the occurrence of abrupt temperature variations in the western Mediterranean during the penultimate interglacial‐to‐glacial cycle.
Hydrologic control of dissolved organic matter biogeochemistry in pools of a subtropical dryland river
Authors: Fellman Jason B. , Dogramaci Shawan , Skrzypek Grzegorz , Dodson Wade , Grierson Pauline F.
Published: June 2011

Dryland rivers function as strongly linked ecologic‐hydrologic systems, including both extended periods of drought and episodic flooding events. However, few studies have combined hydrologic and biogeochemical measurements to better understand the ecology of pools within dryland rivers. We used δ2H and δ18O values of pool water, rainfall, and groundwater combined with pool water measurements of C, N, and P and dissolved organic matter (DOM) fluorescence characteristics to determine (1) the concentration and chemical composition of DOM and (2) the origin of surface water in 16 pools of a dryland river in northern Western Australia. Parallel factor analysis of excitation‐emission matrices showed that humic‐like components derived mainly from terrestrial plant material dominated total DOM fluorescence for all pools. Evaporation models using δ2H and δ18O showed a variety of pool hydrologic regimes, including pools with moderate to high evaporative water loss that were largely isolated from shallow alluvium water inputs and pools with consistent alluvium water throughflow and low evaporation. Concentrations of C, N, and P as well as total DOM fluorescence were generally greater in pools with high evaporative loss and lower in pools with alluvium water inputs. Pool δ2H and δ18O values were also significantly correlated with DOM fluorescence characteristics and C, N, and P concentrations, providing quantitative evidence of the hydrologic influence on DOM biogeochemistry. Taken together, our findings suggest that individual pools function as distinct ecosystems within the riverine environment.
ATM‐mediated phosphorylation of polynucleotide kinase/phosphatase is required for effective DNA double‐strand break repair
Authors: Segal‐Raz Hava , Mass Gilad , Baranes‐Bachar Keren , Lerenthal Yaniv , Wang Shih‐Ya , Chung Young Min , Ziv‐Lehrman Shelly , Ström Cecilia E , Helleday Thomas , Hu Mickey C.‐T. , Chen David J , Shiloh Yosef
Published: June 2011

The cellular response to double‐strand breaks (DSBs) in DNA is a complex signalling network, mobilized by the nuclear protein kinase ataxia‐telangiectasia mutated (ATM), which phosphorylates many factors in the various branches of this network. A main question is how ATM regulates DSB repair. Here, we identify the DNA repair enzyme polynucleotide kinase/phosphatase (PNKP) as an ATM target. PNKP phosphorylates 5′‐OH and dephosphorylates 3′‐phosphate DNA ends that are formed at DSB termini caused by DNA‐damaging agents, thereby regenerating legitimate ends for further processing. We establish that the ATM phosphorylation targets on human PNKP—Ser 114 and Ser 126—are crucial for cellular survival following DSB induction and for effective DSB repair, being essential for damage‐induced enhancement of the activity of PNKP and its proper accumulation at the sites of DNA damage. These findings show a direct functional link between ATM and the DSB‐repair machinery.
Assessment of Attention in People With Aphasia: Challenges and Recommendations
Authors: Connor Lisa Tabor , Fucetola Robert P.
Published: June 2011

Assessing nonverbal cognitive constructs, such as attention, in persons with aphasia is particularly challenging. The most difficult aspect of this task is determining whether language deficits are independent of attention deficits or whether the pattern of preserved and impaired performance reflects a combination of deficits of language and attention. As difficult as the task of assessing attention in people with aphasia may be, teasing apart contributions of language and attention to communication is crucial for appropriate treatment planning and goal-setting for people with communication deficits. Assessment tools, both standardized and non-standardized, are reviewed to help in determining the extent to which types of attention are affected in people with aphasia.
Remarks on logarithmical regularity criteria for the Navier–Stokes equations
Authors: Guo Zhengguang , Gala Sadek
Published: June 2011

In this paper we establish some new logarithmically improved regularity criteria for the Navier–Stokes equations in the homogeneous Besov space \documentclass[12pt]{minimal}\begin{document}$\dot{B}_{\infty ,\infty }^{-1}$\end{document}Ḃ∞,∞−1.
Effects of irradiation and annealing on deep levels in rhodium-doped p-GaAs grown by metal-organic chemical-vapor deposition
Authors: Naz Nazir A. , Qurashi Umar S. , Iqbal M. Zafar
Published: June 2011

This paper reports a detailed study of the effects of irradiation and thermal annealing on deep levels in Rh-doped p-type GaAs grown by low-pressure metal-organic chemical-vapor deposition, using deep level transient spectroscopy (DLTS) technique. It is found upon irradiation with alpha particles that, in addition to the radiation-induced defect peaks, all the Rh-related peaks observed in majority, as well as minority-carrier emission DLTS scans show an increase in their respective concentrations. The usually observed α-induced defects Hα1, Hα2, and Hα3 are found to have lower introduction rates in Rh-doped samples, as compared to reference samples (not doped with Rh). Alpha-irradiation has been found to decompose the two minority carrier emitting bands (one at low temperature ∼150 K and the other at ∼380 K) observed prior to irradiation into distinct peaks corresponding to deep levels Rh1 and Rh2 and EL2 and Rh3, respectively. A similar effect is also observed for the majority-carrier emitting band composed of hole emission from deep levels RhA and RhB, which separate out well upon irradiation. Further, from the double-correlation DLTS measurements, the emission rates of carriers from the radiation-enhanced peaks corresponding to deep levels Rh1, Rh2, Rh3, and RhC were found to be dependent on junction electric field. For RhC, the field dependence data have been analyzed in terms of the Poole-Frenkel model employing a 3-dimensional Coulomb potential with q = 2e (electronic charge). Temperature dependence of the hole capture cross-sections of the levels RhA and RhC was also studied quantitatively. The observed dependence of the hole capture cross-section of RhC on temperature can be interpreted in terms of multiphonon capture model, yielding a capture barrier of 0.2 eV and σ(∞) = 2.3 × 10−14 cm2. The results of irradiation and isochronal thermal annealing study, in combination with the theoretical analysis of the field dependence of hole emission data, lead us to interpret the levels RhA and RhB as charged centers and probably complexes of arsenic anti-site defect (AsGa) with Rh-impurity, (AsGa-Rh). The levels Rh1 and Rh2 are also proposed to be complexes, albeit of a different type, of arsenic anti-site defects (AsGa) and Rh-impurity (AsGa-Rh), while the level RhC is likely to be a doubly-charged complex center composed of arsenic interstitial (IAs) and Rh-impurity (IAs-Rh).
X-ray and runaway electron generation in repetitive pulsed discharges in atmospheric pressure air with a point-to-plane gap
Authors: Shao Tao , Tarasenko Victor F. , Zhang Cheng , Shut’ko Yuliya V. , Yan Ping
Published: June 2011

In this paper, using two repetitive nanosecond generators, x-rays were detected in atmospheric air with a highly inhomogeneous electric field by a point-to- plane gap. The rise times of the generators were about 15 and 1 ns. The x-rays were directly measured by various dosimeters and a NaI scintillator with a photomultiplier tube. X-rays were detected in the continuous mode at pulse repetition frequency up to 1 kHz and a voltage pulse rise time of ∼15 ns. It is shown that the maximum x-ray intensity is attainable at different pulse repetition frequencies depending on the voltage pulse parameters and cathode design. In atmospheric pressure air the x-ray intensity is found to increase with increasing the pulse repetition frequency up to 1 kHz. It is confirmed that the maximum x-ray intensity is attained in a diffuse discharge in a point-to-plane gap.
Resolution of the Abraham-Minkowski debate: Implications for the electromagnetic wave theory of light in matter
Authors: Kemp B. A.
Published: June 2011

A century has now passed since the origins of the Abraham-Minkowski controversy pertaining to the correct form of optical momentum in media. Experiment and theory have been applied at both the classical and quantum levels in attempt to resolve the debate. The result of these efforts is the identification of Abraham’s kinetic momentum as being responsible for the overall center of mass translations of a medium and Minkowski’s canonical or wave momentum as being responsible for translations within or with respect to a medium. In spite of the recent theoretical developments, much confusion still exists regarding the appropriate theory required to predict experimental outcomes and to develop new applications. In this paper, the resolution of the longstanding Abraham-Minkowski controversy is reviewed. The resolution is presented using classical electromagnetic theory and logical interpretation of experiments disseminated over the previous century. Emphasis is placed on applied physics applications: modeling optical manipulation of cells and particles. Although the basic interpretation of optical momentum has been resolved, there is still some uncertainly regarding the complete form of the momentum continuity equation describing electromagnetics. Thus, while a complete picture of electrodynamics has still yet to be fully interpreted, this correspondence should help clarify the state-of-the-art view.
Analytical model for the transmission of electromagnetic waves through arrays of slits in perfect conductors and lossy metal screens
Authors: Yang Rui , Rodríguez-Berral Raúl , Medina Francisco , Hao Yang
Published: June 2011

This paper presents a very simple analytical model for the analysis of the resonant transmission of microwaves or millimeter waves through periodically distributed slits in a thick metal screen. The model is based on equivalent circuits consisting of transmission line elements of known characteristic admittances and propagation constants loaded by capacitors. Closed-form analytical expressions are provided for all the circuit parameters. Alternatively, the circuit parameters can be quickly computed from numerical simulations carried out at a few frequency points. The proposed analytical model accounts for all the details of the observed transmission spectrum, including conventional Fabry-Pérot (FP) resonances, which are controlled by the thickness of the screen, as well as extraordinary transmission peaks, which are related to the periodicity. The range of validity of the model as a function of dimensional parameters is discussed. The experimentally observed and numerically predicted redshift of the Fabry-Pérot transmission peaks with respect to the ideal Fabry-Pérot resonance condition is accurately accounted for by the capacitors of the model. For narrow slits, the extraordinary transmission peak is linked to the singular behavior of the capacitances at the Rayleigh-Wood anomaly frequency point. Finally, the effect of the lossy nature of the metal screens is included in the model, providing accurate predictions of the transmission losses. Additionally, for lossy screens the model adequately predicts the anomalous behavior of the above mentioned redshift when the slit width becomes comparable to the skin depth in the metal, which is in good agreement with experimental and theoretical data previously reported for a single slit.
Measuring electric-field-induced birefringence in polymer stabilized blue-phase liquid crystals based on phase shift measurements
Authors: Lin Yi-Hsin , Chen Hung-Shan , Wu Chun-Hung , Hsu Hsu-Kuan
Published: June 2011

A simple optical method to measure the electric-field-induced birefringence and Kerr constant of polymer-stabilized blue-phase liquid crystals (PSBP-LC) is demonstrated. By measuring the phase shift of PSBP-LC and the averaged refractive index of PSBP-LC at the voltage-off state, the ordinary refractive index and extraordinary refractive index of PSBP-LC as function of applied voltage can be obtained experimentally. As a result, the electric-field-induced birefringence and Kerr constant can be determined as well. The method we proposed can help in designing PSBP-LC–based photonic devices.
Evolution and ripening of Ge crystals grown by nanoscale induced lateral epitaxy on localized oxide
Authors: Yam V. , Cammilleri V. D. , Fossard F. , Renard C. , Vincent L. , Fazzini P. F. , Bouchier D.
Published: June 2011

We have previously demonstrated that a high quality Ge on SiO2 layer can be grown by nanoscale seed induced lateral epitaxy, using a method based on the standard local oxidation of silicon technique for creating nanoscale silicon seeds. The growth of Ge from germane is initiated in two silicon seed lines and evolves toward a complete wetting of the SiO2 stripe after coalescence. For isolated crystals, the wetting mechanism of SiO2 by Ge is strongly dependent upon the seed orientation and closely related to the development of {111} facets. We show here that the energetic balance between different surface and interface energies governs the wetting configuration of SiO2 by Ge, and therefore defines the angle of contact between Ge and SiO2, that can only be satisfied by the development of a (11-1) facet in the case studied. We derive from Young’s equation an interfacial energy between Ge and SiO2 equal to 5.67 eV/nm2. We show that the coalescence of Ge crystals is mainly driven by surface diffusion, which includes two main aspects. Diffusion driven by the chemical potential gradient due to the variation of seed curvatures leads to preferential nucleation at concave corners of patterns. At the same time, a ripening phenomenon is observed when the two crystals come in contact with each other.
Membrane-type metamaterials: Transmission loss of multi-celled arrays
Authors: Naify Christina J. , Chang Chia-Ming , McKnight Geoffrey , Scheulen Florian , Nutt Steven
Published: June 2011

Acoustic metamaterials with negative dynamic mass density have been shown to demonstrate a five-fold increase in transmission loss (TL) over mass law predictions for a narrowband (100 Hz) at low frequencies (100–1000 Hz). The present work focuses on the scale-up of this effect by examining the behavior of multiple elements arranged in arrays. Single membranes were stretched over rigid frame supports and masses were attached to the center of each divided cell. The TL behavior was measured for multiple configurations with different magnitudes of mass distributed across each of the cell membranes in the array resulting in a multipeak TL profile. To better understand scale-up issues, the effect of the frame structure compliance was evaluated, and more compliant frames resulted in a reduction in the TL peak frequency bandwidth. In addition, displacement measurements of frames and membranes were performed using a laser vibrometer. Finally, the measured TL of the multi-celled structure was compared with the TL behavior predicted by finite element analysis to understand the role of nonuniform mass distribution and frame compliance.
Lattice thermal conductivity of a silicon nanowire under surface stress
Authors: Liangruksa Monrudee , Puri Ishwar K.
Published: June 2011

The effects of surface stress on the lattice thermal conductivity are investigated for a silicon nanowire. A phonon dispersion relation is derived based on a continuum approach for a nanowire under surface stress. The phonon Boltzmann equation and the relaxation time are employed to calculate the lattice thermal conductivity. Surface stress, which has a significant influence on the phonon dispersion and thus the Debye temperature, decreases the lattice thermal conductivity. The conductivity varies with changing surface stress, e.g., due to adsorption layers and material coatings. This suggests a phonon engineering approach to tune the conductivity of nanomaterials.
The unification of filament and interfacial resistive switching mechanisms for titanium dioxide based memory devices
Authors: Zhang F. , Li X. M. , Gao X. D. , Wu L. , Cao X. , Liu X. J. , Yang R.
Published: June 2011

Reversible and controllable conversion between unipolar and bipolar resistive switching (URS and BRS) was observed in Pt/TiO2/Pt memory devices. The URS and BRS of this device exhibited different low resistance states but shared the same high resistance state. The conduction mechanisms of low resistance states in URS and BRS are Ohmic conduction and electrons tunneling, respectively, while the high resistance state is controlled by Schottky barrier formed at the top interface of Pt/TiO2. The temperature dependence of resistance states indicates Magnéli phase filaments formed in URS. A unified model was then proposed to demonstrate the unification of filament and interfacial switching mechanisms.
Systematic characterization of degas-driven flow for poly(dimethylsiloxane) microfluidic devices
Authors: Liang David Y. , Tentori Augusto M. , Dimov Ivan K. , Lee Luke P.
Published: June 2011

Degas-driven flow is a novel phenomenon used to propel fluids in poly(dimethylsiloxane) (PDMS)-based microfluidic devices without requiring any external power. This method takes advantage of the inherently high porosity and air solubility of PDMS by removing air molecules from the bulk PDMS before initiating the flow. The dynamics of degas-driven flow are dependent on the channel and device geometries and are highly sensitive to temporal parameters. These dependencies have not been fully characterized, hindering broad use of degas-driven flow as a microfluidic pumping mechanism. Here, we characterize, for the first time, the effect of various parameters on the dynamics of degas-driven flow, including channel geometry, PDMS thickness, PDMS exposure area, vacuum degassing time, and idle time at atmospheric pressure before loading. We investigate the effect of these parameters on flow velocity as well as channel fill time for the degas-driven flow process. Using our devices, we achieved reproducible flow with a standard deviation of less than 8% for flow velocity, as well as maximum flow rates of up to 3 nL/s and mean flow rates of approximately 1–1.5 nL/s. Parameters such as channel surface area and PDMS chip exposure area were found to have negligible impact on degas-driven flow dynamics, whereas channel cross-sectional area, degas time, PDMS thickness, and idle time were found to have a larger impact. In addition, we develop a physical model that can predict mean flow velocities within 6% of experimental values and can be used as a tool for future design of PDMS-based microfluidic devices that utilize degas-driven flow.
Influence of shallow traps on time-resolved optically stimulated luminescence measurements of Al2O3:C,Mg
Authors: Denis G. , Akselrod M. S. , Yukihara E. G.
Published: June 2011

The objective of this paper is to investigate the influence of shallow traps on the signals from Al2O3:C,Mg obtained using time-resolved optically stimulated luminescence (TR-OSL) measurements through experiments and numerical simulations. TR-OSL measurements of Al2O3:C,Mg were carried out and the resulting optically stimulated luminescence (OSL) curves were investigated as a function of the temperature. The numerical simulations were carried out using the rate-equations for a simplified model of Al2O3:C,Mg containing two types of luminescence centers with different luminescence lifetimes and three types of electron traps (a shallow trap, a main dosimetric trap, and a thermally disconnected deep trap). Both experimental results and simulations show that the OSL signals during and between the stimulation pulses are affected by the presence of shallow traps. However, with an appropriate choice of timing parameters, the influence of shallow traps can be reduced by calculating the difference between the signals during and between stimulation pulses. Therefore, TR-OSL can be useful in dosimetry using materials having a large concentration of shallow traps and OSL components with short luminescence lifetimes, for example Al2O3:C,Mg and BeO. Our results also show that the presence of shallow traps has to be taken into account when using the TR-OSL for discrimination between luminescence centers with different luminescence lifetimes, or separation between the OSL from different materials based on their characteristic luminescence lifetimes. The experimental results also show evidence of thermal assistance in the OSL process of Al2O3:C,Mg.
Dynamic mechanical response of magnesium single crystal under compression loading: Experiments, model, and simulations
Authors: Li Qizhen
Published: June 2011

Magnesium single crystal samples are compressed at room temperature under quasistatic (∼0.001 s−1) loading in a universal testing machine and dynamic (430, 1000, and 1200 s−1) loading in a split Hopkinson pressure bar system. Stress-strain curves show that (a) the fracture strain slightly increases with the strain rate; and (b) the maximum strength and strain hardening rate increase significantly when the testing changes from quasistatic to dynamic, although they do not vary much when the strain rate for dynamic testing varies in the range of 430–1200 s−1. The operation of the secondary pyramidal slip system is the dominating deformation mechanism, which leads to a fracture surface with an angle of ∼42° with respect to the loading axial direction. A theoretical material model based on Johnson-Cook law is also derived. The model includes the strain hardening and strain rate hardening terms, and provides the stress-strain relations matching with the experimental results. Finite element simulations for the strain rates used in the experiments predict the mechanical responses of the material that agree well with the experimental data.