bluuebunny/crossref_metadata_2025 huggingface dataset:
‘An avalanche of tragedy’: Modern girls and the murder of Mrs Mick
Authors: Glasbeek Amanda
Published: June 2012

On 24 May 1925, three young women incarcerated at the Concord Industrial Jail Farm for Women (near Toronto, Ontario) wrestled the night matron, Mrs Mick, to the ground, tied her down, took her keys and escaped from prison. Tragically, Mrs Mick suffered a stroke and died while chained to the prison washbasins. Upon their capture, the two 16-year-olds and one 19-year-old were charged with murder in a case that would capture the attention of the local press and hold it for weeks. This article analyses this case as an exemplary instance of the distinctly gendered world of criminal offending. Characterized as ‘an avalanche of tragedy’ by the local press, the death of Mrs Mick offers historical testimony to the complexity of women's entanglements with the criminal justice system and to the relationship between women's violence and their victimization as criminalized subjects.
A Direct Method for Measuring Discounting and QALYs More Easily and Reliably
Authors: Attema Arthur E. , Bleichrodt Han , Wakker Peter P.
Published: June 2012

Time discounting and quality of life are two important factors in evaluations of medical interventions. The measurement of these two factors is complicated because they interact. Existing methods either simply assume one factor given, based on heuristic assumptions, or invoke complicating extraneous factors, such as risk, that generate extra biases. The authors introduce a method for measuring discounting (and then quality of life) that involves no extraneous factors and that avoids distorting interactions. Their method is considerably simpler and more realistic for subjects than existing methods. It is entirely choice based and thus can be founded on economic rationality requirements. An experiment demonstrates the feasibility of this method and its advantages over classical methods.
Minimal clinically important change on the Headache Impact Test-6 questionnaire in patients with chronic tension-type headache
Authors: Castien René F , Blankenstein Annette H , Windt Daniëlle AWM van der , Dekker Joost
Published: June 2012

Objective: To determine the minimal clinically important change (MCIC) in Headache Impact Test-6 (HIT-6) score in patients with chronic tension-type headache (CTTH).

Methods: The HIT-6 was administered at baseline and at 8 weeks follow-up in a cohort of 186 participants with CTTH who received manual therapy or usual care by their general practitioner. An anchor-based method was used to determine the MCIC, with the external criterion (anchor) being based on general perceived improvement (‘much improved or very much improved’ on a 7-point Likert scale) in combination with 50% reduction in headache days. Using receiver operating characteristic (ROC) curve analysis we defined an optimal cut-off score discriminating between improved and not improved participants.

Results: The optimal cut-off point for the MCIC for the HIT-6 was −8 points, on a total scale range of 42 points.

Conclusion: A clinically relevant improvement in patients with CTTH is reflected by a decrease of at least 8 points on the HIT-6.
Bilateral Mini-Invasive Adductor Tenotomy for the Management of Chronic Unilateral Adductor Longus Tendinopathy in Athletes
Authors: Maffulli Nicola , Loppini Mattia , Longo Umile Giuseppe , Denaro Vincenzo
Published: June 2012

Background:

To date, the best management of chronic groin pain related to adductor longus tendinopathy has not been defined. Although there have been some studies investigating the effectiveness of adductor longus tenotomy, none have investigated bilateral adductor tenotomy for unilateral tendinopathy.

Hypothesis:

The use of bilateral percutaneous adductor tenotomy for the management of chronic unilateral groin pain as a result of adductor longus tendinopathy will result in improvement of overall function and facilitate a return to athletic activity.

Study Design:

Case series; Level of evidence, 4.

Methods:

During the period from 2004 to 2007, we prospectively enrolled 29 consecutive athletes (26 male and 3 female; median age, 28 years) with chronic groin pain from unilateral adductor longus tendinopathy who underwent bilateral adductor tenotomy. Functional outcome and health status were assessed with the Hip Disability and Osteoarthritis Outcome Score (HOOS), Short Form Health Survey (SF-36), and European Quality of Life–5 Dimensions scale (EQ-5D). The ability to participate in sport before and after surgery and the time to return to training and return to sport were also recorded. The median follow-up after surgery was 36 months.

Results:

All questionnaires showed a statistically significant improvement ( P < .0001) after surgery. At the time of latest follow-up, 20 of 29 patients (69%) returned to their preinjury level of sport and 2 of 29 patients (7%) to higher levels compared with preinjury status. However, 4 of 29 patients (14%) returned to sport at lower levels than those of preinjury status, and 3 of 29 patients (10%) ceased to participate in sport. The median time to return to training was 11 weeks and to return to sport was 18 weeks.

Conclusion:

Bilateral mini-invasive adductor tenotomy can be an effective treatment for athletes suffering from unilateral chronic groin pain associated with adductor longus tendinopathy refractory to nonoperative management.
Magnetic Resonance Imaging Identification of Rotator Cuff Retears After Repair
Authors: Khazzam Michael , Kuhn John E. , Mulligan Ed , Abboud Joseph A. , Baumgarten Keith M. , Brophy Robert H. , Jones Grant L. , Miller Bruce , Smith Matthew , Wright Rick W.
Published: June 2012

Background:

Magnetic resonance imaging (MRI) is the most commonly used imaging modality to assess the rotator cuff. Currently, there are a limited number of studies assessing the interobserver and intraobserver reliability of MRI after rotator cuff repair.

Hypothesis:

Fellowship-trained orthopaedic shoulder surgeons will have good inter- and intraobserver agreement with regard to features of the repaired rotator cuff (repair integrity, fat content, muscle volume, number of tendons involved, tear size, and retract) on MRI.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

Seven fellowship-trained orthopaedic shoulder surgeons reviewed 31 MRI scans from 31 shoulders from patients who had previous rotator cuff repair. The scans were evaluated for the following characteristics: rotator cuff repair status (full-thickness retear vs intact repair), tear location, tendon thickness, fatty infiltration, atrophy, number of tendons involved in retear, tendon retraction, status of the long head of the biceps tendon, and bone marrow edema in the humeral head. Surgeons were asked to review images at 2 separate time points approximately 9 months apart and complete an evaluation form for each scan at each time point. Multirater kappa (κ) statistics were used to assess inter- and intraobserver reliability.

Results:

The interobserver agreement was highest (80%, κ = 0.60) for identifying full-thickness retears, tendon retear retraction (64%, κ = 0.45), and cysts in the greater tuberosity (72%, κ = 0.43). All other variables were found to have fair to poor agreement. The worst interobserver agreement was associated with identifying rotator cuff footprint coverage (47%, κ = −0.21) and tendon signal intensity (29%, κ = −0.01). The mean intraobserver reproducibility was also highest (77%-90%, κ = 0.71) for full-thickness retears, quality of the supraspinatus (47%-83%, κ = 0.52), tears of the long head of the biceps tendon (58%-94%, κ = 0.49), presence of bone marrow edema in the humeral head (63%-87%, κ = 0.48), cysts in the greater tuberosity (70%-83%, κ = 0.47), signal in the long head of the biceps tendon (60%-80%, κ = 0.43), and quality of the infraspinatus (37-90%, κ = 0.43). The worst intraobserver reproducibility was found in identification of the location of bone marrow edema (22%-83%, κ = −0.03).

Conclusion:

The results of this study indicate that there is substantial variability when evaluating MRI scans after rotator cuff repair. Intact rotator cuff repairs or full-thickness retears can be identified with moderate reliability. These findings indicate that additional imaging modalities may be needed for accurate assessment of the repaired rotator cuff.
Infant embodiment and interembodiment: A review of sociocultural perspectives
Authors: Lupton Deborah
Published: June 2012

This article brings together a range of research and scholarship from various disciplines which have investigated and theorized social and cultural aspects of infants’ bodies within the context of contemporary western societies. It begins with a theoretical overview of dominant concepts of infants’ bodies, including discussion of the concepts of the unfinished body, civility and the Self/Other binary opposition as well as that of interembodiment, drawn from the work of Merleau-Ponty. Then follows discussion of the pleasures and challenging aspects of interembodiment in relation to caregivers’ interactions with infants’ bodies, purity, danger and infant embodiment and lastly practices of surveilling the vulnerable, ‘at risk’ infant body.
An investigation of the strain rate and temperature effects on the plastic flow stress and ductile failure strain of aluminum alloys 5083-H116, 6082-T6 and a 5183 weld metal
Authors: Zhou Jun , Hayden Matthew , Gao Xiaosheng
Published: June 2012

This article presents a comprehensive experimental and numerical study to investigate the effects of strain rate and temperature on flow stress and ductile failure strain of three aluminum alloys. The test matrix includes smooth and notched round tensile specimens tested at room temperature (24 ℃) and two elevated temperatures (66 ℃ and 149 ℃), and under different strain rates. For 5083-H116, three loading rates are considered at 24 ℃ and it is found that the flow stress and failure strain are lowest at the intermediate strain rate. At high strain rate, the flow stresses of 5083-H116 and 6082-T6 are higher than the quasi-static loading while the flow stress of the 5183 weld metal remains unchanged; the ductility of the 5XXX alloys shows a significant increase compared to the quasi-static loading while the ductility of 6082-T6 does not change much. The study indicates that the Johnson–Cook plasticity and fracture models can be used to describe the temperature dependencies of the flow stress and the failure strain for 6082-T6 but not the 5XXX alloys. At 66 ℃ the 5XXX alloys do not display temperature softening compared to 24 ℃ while their ductility is reduced. As temperature is elevated to 149 ℃, the flow stress of the 5XXX alloys decreases while the ductility increases. The unconventional behavior of the 5XXX alloys in certain temperature and strain rate ranges has been attributed to the dynamic strain aging effect. The study also suggests that the dependency of the failure strain on stress triaxiality can be described by the Johnson–Cook fracture model for all three materials under quasi-static loading at room temperature and the model parameters are calibrated using an inverse method combining experimental results with finite element analysis.
Optimization of limestone sawing using circular saws with reference to unit wear and energy
Authors: Bayram Fatih , Yasitli Nazmi Erhan , Kulaksiz Seyfi , Ozcelik Yilmaz
Published: June 2012

Natural stone processing operations use different methods and machines; however, the circular sawing machines are widely used in natural stone processing since they can be used flexibly. The wear on the diamond segments on the sawblade and energy consumption are the important parameters for these machines. Unit wear and unit energy should be minimized and the sawing rate should be maximized for optimum sawing condition. In this study sawing tests were performed on limestone samples using a fully automatic circular sawing machine. The tests were conducted at different peripheral speeds and advance rates. For each sawing test, the segment wear and consumed energy were measured. The statistical software, Design Expert 7.0 was used to analyze the test data. The new sawability charts for wear and energy were developed. The unique aspect of this study is to determine the optimum circular sawing performance with the special software and this technique also provides the prediction of unit wear and unit energy for selected sawing condition.
Dynamic simulation studies and experiments on rubber structures used in rail vehicles
Authors: Luo Robert K , Wu Xiaoping , Mortel William J
Published: June 2012

Rail vehicles operate in highly complex dynamic environments. Rubber-to-metal bonded springs are used as both primary and secondary suspensions as well as engine installations in order to minimize vibration levels. The effect of rubber hysteresis is usually studied using viscoelastic models; however, this paper proposes an approach in which Rayleigh damping coefficients are introduced to model the rubber hysteresis. Simulations of the dynamic response of a rectangular rubber spring are performed and it is found that the natural frequencies of the rubber suspensions and engine installations on a railway vehicle show little change under both the tare and loaded conditions in service. The steady state dynamic response to a harmonic input in the frequency range between 1 and 1000 Hz is calculated and subsequently validated against experimental results. In addition the effect of a sudden impact, created by track irregularities, on the rubber suspension and engine installation is analysed. The proposed methodology may be used to guide the design of the rubber structures used in railway vehicles.
Microtubule circumferential vibrations in cytosol
Authors: Daneshmand Farhang
Published: June 2012

Microtubules are key components of the cytoskeleton and perform a variety of functions, including chromosome movement during cell division, intracellular transport of materials, movement of organelles and intracellular tracking. A combination of essential and up-to-date methods is needed for investigating the biology of microtubules and understanding the mechanisms of microtubule–drug interaction. Coupled cytosol–microtubule mechanical vibrations of microtubules are studied in this article. Such investigations provide helpful insights on the functional mechanisms of microtubules and their interactions with other proteins and drugs. The viscous cytosol and the microtubule are coupled through the continuity condition across the microtubule–cytosol interface. The stress field in the cytosol induced by vibrating microtubule is analytically determined and the coupled circumferential vibrations of the cytosol–microtubule system are investigated by developing a coupled polynomial eigenvalue problem. Finally, the variations of vibration frequencies of a coupled system with cytosol dynamic viscosity, and microtubule circumferential Young’s modulus are examined. Furthermore, the validity of the present analysis is confirmed by comparing the results with those obtained from the literature.
A study of unsteady physiological magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping
Authors: Tripathi Dharmendra , Bég O Anwar
Published: June 2012

Magnetohydrodynamic peristaltic flows arise in controlled magnetic drug targeting, hybrid haemodynamic pumps and biomagnetic phenomena interacting with the human digestive system. Motivated by the objective of improving an understanding of the complex fluid dynamics in such flows, we consider in the present article the transient magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping. Reynolds number is small enough and the wavelength to diameter ratio is large enough to negate inertial effects. Analytical solutions for temperature field, axial velocity, transverse velocity, pressure gradient, local wall shear stress, volume flowrate and averaged volume flowrate are obtained. The effects of the transverse magnetic field, Grashof number and thermal conductivity on the flow patterns induced by peristaltic waves (sinusoidal propagation along the length of channel) are studied using graphical plots. The present study identifies that greater pressure is required to propel the magneto-fluid by peristaltic pumping in comparison to a non-conducting Newtonian fluid, whereas, a lower pressure is required if heat transfer is effective. The analytical solutions further provide an important benchmark for future numerical simulations.
The impact of clinical encounters on student nurses’ ethical caring
Authors: Pedersen Birgith , Sivonen Kerstin
Published: June 2012

The aim of this study was to get a deeper understanding of student nurses’ experiences of personal caring ethics by reflection on caring encounters with patients in clinical practice, ethical caring ideals, ethical problems, and sources for inner strength that give courage to practice good caring. In all, 24 Scandinavian student nurses participated voluntarily in an interview study. The interviews were analyzed within a phenomenological–hermeneutical approach and revealed three themes. The students found themselves in two different states of vulnerability: one in which they were overwhelmed by their vulnerability and began to suffer themselves and the other where their vulnerability became a source of development with focus on the patient. The students’ ethical caring ideals served as fixed reference points in their ethical development, but their ideals were at risk of decline. The students reflected on the barriers for performing ethical care and nurtured their ethical ideals by providing ethical care in secret. Caring in secret occurred also when student nurses did not experience a shared ethos.
“We’re Still in a Struggle”
Authors: Goodkind Jessica R. , Hess Julia Meredith , Gorman Beverly , Parker Danielle P.
Published: June 2012

As part of a community/university collaborative effort to promote the mental health and well-being of Diné (Navajo) youth, we explored the relevance of addressing historical trauma and current structural stressors, and of building on individual and community strengths through healing and social transformation at multiple levels. Qualitative analyses of 74 ethnographic interviews with 37 Diné youth, parents, and grandparents suggested that a focus on historical trauma as a conceptual frame for behavioral health inequities, understood within the context of resilience and survival, is appropriate. Our findings also highlight the salience of current stressors such as poverty and violence exposure. We explore the fit of an historical trauma healing framework and present implications for intervention and transformation through revitalization of traditional knowledge, culturally based healing practices, intergenerational education, and social change strategies designed to eliminate social inequities.
Clinical pharmacy services and research for lymphoma patients at a cancer center
Authors: Chan Alexandre , Shih Vivianne , Chiang Joen , Chew Lita , Tay Kevin , Quek Richard , Tao Miriam , Lim Soon Thye
Published: June 2012

At the National Cancer Centre Singapore, which is currently the largest ambulatory cancer centre in Singapore, clinical pharmacists have taken upon responsibilities to provide direct pharmaceutical care in the center’s lymphoma team since 2006. Given the complexity and intricacies of lymphoma treatments, clinical pharmacists are often positioned to ensure supportive care is optimized among these patients. Besides management of chemotherapy-related and supportive care issues, clinical pharmacists play a pivotal role in guiding cost-effective and safe prescribing. In collaboration with the medical team, they are also involved in conducting practice research in order to optimize the delivery of pharmaceutical care. In this report, the dedicated services and research activities conducted by clinical pharmacists of a lymphoma team will be discussed.
Ovarian remnant syndrome and uterine stump pyometra in three queens
Authors: Demirel Murside Ayse , Acar Duygu Baki
Published: June 2012

Ovarian remnant syndrome (ORS) is the presence of functional ovarian tissue with signs of oestrus as a complication after ovariohysterectomy (OHE) or ovariectomy. Stump pyometra is another complication that can be observed after OHE. However, there are few reports about ORS and stump pyometra in queens. In this report, three queens with recurrent oestrous behaviours after OHE are described. In two queens, ORS with stump pyometra was diagnosed and in one queen ORS alone was diagnosed by physical examination, medical history, vaginal cytology and ultrasonography. Remnant ovarian and uterine tissues were removed by laparotomy. Two queens recovered without any complications; however, one queen died 2 days after surgery. This study reveals that ORS and stump pyometra can result in severe disease and can be fatal.
Globalization and cosmopolitanism: Continuity and disjuncture, contemporary and historical
Authors: Barbalet Jack
Published: June 2012

Globalization and cosmopolitanism are treated differently in various literatures. The relations of each to the political state and migration, in terms of mobilities and enclavement, are also variably treated in different sources. The article shows that these concerns are not confined to early 21st-century developments but drew attention in accounts of globalization in 17th- and 18th-century social economies.
Flow and cooperative learning in civic game play
Authors: Raphael Chad , Bachen Christine M. , Hernández-Ramos Pedro F.
Published: June 2012

Flow theory offers an individualistic explanation of media enjoyment, while cooperative learning theory posits a social explanation for enhanced learning in groups. This classroom-based experimental study examines whether game players can experience both conditions and the influence of each on several types of civic knowledge, skills, and dispositions. We find that high quality cooperative learning contributed to acquiring civic knowledge and skills. In contrast, flow was more influential for developing dispositions to empathy and interest in learning more about the game topics. Thus, we conclude that players can experience flow while engaged in cooperative learning, but that these two conditions may support different kinds of civic learning.
The reluctant researcher: shyness in the field
Authors: Scott Susie , Hinton-Smith Tamsin , Härmä Vuokko , Broome Karl
Published: June 2012

Despite the attention qualitative researchers have given to the interaction context and social process of data collection, there has been scant recognition of the dramaturgical dilemmas this poses for the fieldworker. Respondents have been caricatured in an essentialist typology, ranging from the ideal to the reluctant, while the researcher has been assumed to take a relatively privileged position as director of the drama. Here we report on a study of shyness in art galleries and museums, using extracts from our fieldnotes to illustrate how researchers may themselves be prone to feelings of self-consciousness, incompetence and impostordom. Different methodologies and fieldwork scenarios can be located along a ‘cringe spectrum’, to the extent that they involve high levels of performance, improvisation and interactional contingency. We discuss the strategies used by shy and non-shy members of our team to manage such dramaturgical stress, and argue for more reflexive dialogue about this issue.
The validity of a grounded theory approach to research on democratization
Authors: Hardman Helen
Published: June 2012

This paper attempts to demonstrate that a grounded theory textual analysis yields results that are equally important as more traditional forms of inquiry, such as archival research. The research employed a grounded theory approach in a CAQDAS1 textual analysis of the published minutes of three communist party meetings, held in Hungary, Serbia and the Soviet Union in 1988. The purpose of the analysis was to reveal nuance in delegates’ speeches at a time when, officially, ‘monolithic unity’ in the party required members to express wholehearted support for their leaderships’ policies, and yet at the same time these regimes were in the process of liberalizing, and party members had begun expressing their own preferences. But, the few speakers at these meetings who advocated far-reaching changes often chose to allude to taboo subjects in a coded way, while their hardline, conservative superiors sprinkled their speeches with terms that are traditionally associated with liberal democracies. Interpretive coding of text enabled recording of a more fine-grained reading of these minutes, while the application of grounded theory provided a tabula rasa which generated a model that was common to all three cases.
Forced Manager Turnovers in English Soccer Leagues
Authors: d’Addona Stefano , Kind Axel
Published: June 2012

The authors conduct an empirical analysis of a hand-collected sample of 2,376 turnovers of soccer managers in the four major English leagues in the seasons from 1949-1950 to 2007-2008. While the relation between the probability of a manager being fired and long-term performance remained remarkably stable, both the absolute frequency and the sensitivity of firing decisions on the outcome of recent matches steadily and significantly increased during the six decades covered by the sample. This is likely to reflect the increased level of competition in and economic importance of the English soccer leagues.
How I manage venous thromboembolism risk in hospitalized medical patients
Authors: Dobromirski Mark , Cohen Alexander T.
Published: June 2012

Venous thromboembolism is a significant cause of illness and death worldwide. Large bodies of evidence support the heightened risk status of hospitalized medical patients, and that prophylactic measures significantly reduce the risk of thrombosis, yet these patients often fail to receive adequate prophylactic therapy. This failure may be accounted for by a lack of awareness of the relevant indications, poorly designed implementation systems, and clinical concerns over the side effects of anticoagulant medications. This article briefly summarizes our understanding of the clinical factors relevant to the evaluation of venous thromboembolism risk in hospitalized medical patients. We describe our approach to the use of thromboprophylaxis, through which we aim to minimize the disease burden of this under-recognized and preventable pathology.
Slc11a1 (Nramp1) impairs growth of Salmonella enterica serovar typhimurium in macrophages via stimulation of lipocalin-2 expression
Authors: Fritsche Gernot , Nairz Manfred , Libby Stephen J , Fang Ferric C , Weiss Günter
Published: June 2012

Nramp1 confers resistance of macrophages to Salmonella Typhimurium via NF-κB-dependent induction of the siderophore capturing peptide lipocalin-2.

The expression of the cation transporter Nramp1 (Slc11a1) in late phagolysosomes confers resistance to infection with several intracellular pathogens, such as Salmonella enterica, in mice. The antimicrobial actions of Nramp1 are attributable, in part, to modulation of macrophage immune function and cellular iron metabolism—the latter affecting the availability of the essential nutrient iron for intraphagosomal bacteria. Here, we provide novel evidence that Nramp1 functionality increases the expression of the peptide Lcn2, which exerts its antimicrobial activity by scavenging iron-loaded bacterial siderophores and mediating iron efflux from macrophages. With the use of macrophage cell lines expressing functional or nonfunctional Nramp1, we found significantly elevated Lcn2 mRNA and protein levels in Nramp1-expressing cells. These resulted from Nramp1-mediated alterations in the production of ROS, which stimulated NF-κB activity and subsequently, Lcn2 transcription. We observed that increased Lcn2 levels in primary Nramp1-positive macrophages resulted in a significant suppression of S. enterica serovar typhimurium growth. Stimulation of Lcn2 expression is a novel mechanism by which Nramp1 confers resistance against infection with the intracellular bacterium S. typhimurium.
Eosinophil contamination of thioglycollate-elicited peritoneal macrophage cultures skews the functional readouts of in vitro assays
Authors: Misharin Alexander V , Saber Rana , Perlman Harris
Published: June 2012

Eosinophil contamination affects thioglycollate-elicited peritoneal macrophage responses during in vitro stimulation.

Thioglycollate-elicited peritoneal cells are a common source of macrophages for various in vitro assays, including stimulation with TLR ligands, cell signaling assays, phagocytosis, toxicology studies, and cytokine/chemokine production. The most common method for enrichment of cultured thioglycollate-elicited peritoneal cells is adherence. However, the presence of other cell types in freshly isolated and cultured thioglycollate-elicited peritoneal cells has not been examined. Here, we demonstrate that thioglycollate-elicited peritoneal cavity contains 55–60% nonmacrophage cells, and even after adherence, there are still 12–20% nonmacrophage cells remaining. Excluding macrophages, eosinophils are the major cell type in the freshly elicited cavity (30–40%). Eosinophils are also the major cell type contaminating in vitro cultures of thioglycollate-elicited peritoneal macrophages. Moreover, the contamination of macrophage cultures by eosinophils significantly diminishes activation of p38 MAPK and the serine threonine kinase Akt and production of proinflammatory cytokines in response to LPS stimulation. Taken together, these data suggest that thioglycollate-elicited peritoneal cells are far more heterogeneous than reported previously. Further, a failure to remove contaminating eosinophils may greatly affect the interpretation of results obtained with cultured thioglycollate-elicited macrophages. Thus, our data indicate that future studies intent on accurately assessing cultured macrophage phenotype and activation require depletion of all cocontaminating cells, especially eosinophils.
On Statistical Properties of Sets Fulfilling Rolling-Type Conditions
Authors: Cuevas A. , Fraiman R. , Pateiro-López B.
Published: June 2012

Motivated by set estimation problems, we consider three closely related shape conditions for compact sets: positive reach, r-convexity, and the rolling condition. First, the relations between these shape conditions are analyzed. Second, for the estimation of sets fulfilling a rolling condition, we obtain a result of ‘full consistency’ (i.e. consistency with respect to the Hausdorff metric for the target set and for its boundary). Third, the class of uniformly bounded compact sets whose reach is not smaller than a given constant r is shown to be a P-uniformity class (in Billingsley and Topsøe's (1967) sense) and, in particular, a Glivenko-Cantelli class. Fourth, under broad conditions, the r-convex hull of the sample is proved to be a fully consistent estimator of an r-convex support in the two-dimensional case. Moreover, its boundary length is shown to converge (almost surely) to that of the underlying support. Fifth, the above results are applied to obtain new consistency statements for level set estimators based on the excess mass methodology (see Polonik (1995)).
Convex Hulls of Uniform Samples from a Convex Polygon
Authors: Groeneboom Piet
Published: June 2012

In Groeneboom (1988) a central limit theorem for the number of vertices Nn of the convex hull of a uniform sample from the interior of a convex polygon was derived. To be more precise, it was shown that {Nn - (2/3)rlogn} / {(10/27)rlogn}1/2 converges in law to a standard normal distribution, if r is the number of vertices of the convex polygon from which the sample is taken. In the unpublished preprint Nagaev and Khamdamov (1991) a central limit result for the joint distribution of Nn and An is given, where An is the area of the convex hull, using a coupling of the sample process near the border of the polygon with a Poisson point process as in Groeneboom (1988), and representing the remaining area in the Poisson approximation as a union of a doubly infinite sequence of independent standard exponential random variables. We derive this representation from the representation in Groeneboom (1988) and also prove the central limit result of Nagaev and Khamdamov (1991), using this representation. The relation between the variances of the asymptotic normal distributions of the number of vertices and the area, established in Nagaev and Khamdamov (1991), corresponds to a relation between the actual sample variances of Nn and An in Buchta (2005). We show how these asymptotic results all follow from one simple guiding principle. This corrects at the same time the scaling constants in Cabo and Groeneboom (1994) and Nagaev (1995).
Asymptotic Dependence for Light-Tailed Homothetic Densities
Authors: Balkema Guus , Nolde Natalia
Published: June 2012

Dependence between coordinate extremes is a key factor in any multivariate risk assessment. Hence, it is of interest to know whether the components of a given multivariate random vector exhibit asymptotic independence or asymptotic dependence. In the latter case the structure of the asymptotic dependence has to be clarified. In the multivariate setting it is common to have an explicit form of the density rather than the distribution function. In this paper we therefore give criteria for asymptotic dependence in terms of the density. We consider distributions with light tails and restrict attention to continuous unimodal densities defined on the whole space or on an open convex cone. For simplicity, the density is assumed to be homothetic: all level sets have the same shape. Balkema and Nolde (2010) contains conditions on the shape which guarantee asymptotic independence. The situation for asymptotic dependence, treated in the present paper, is more delicate.
Implicit Renewal Theory and Power Tails on Trees
Authors: Jelenković Predrag R. , Olvera-Cravioto Mariana
Published: June 2012

We extend Goldie's (1991) implicit renewal theorem to enable the analysis of recursions on weighted branching trees. We illustrate the developed method by deriving the power-tail asymptotics of the distributions of the solutions R to and similar recursions, where (Q, N, C1, C2,…) is a nonnegative random vector with N ∈ {0, 1, 2, 3,…} ∪ {∞}, and are independent and identically distributed copies of R, independent of (Q, N, C1, C2,…); here ‘∨’ denotes the maximum operator.
On the Transient Behavior of Ehrenfest and Engset Processes
Authors: Feuillet Mathieu , Robert Philippe
Published: June 2012

Two classical stochastic processes are considered, the Ehrenfest process, introduced in 1907 in the kinetic theory of gases to describe the heat exchange between two bodies, and the Engset process, one of the early (1918) stochastic models of communication networks. In this paper we investigate the asymptotic behavior of the distributions of hitting times of these two processes when the number of particles/sources goes to infinity. Results concerning the hitting times of boundaries in particular are obtained. We rely on martingale methods; a key ingredient is an important family of simple nonnegative martingales, an analogue, for the Ehrenfest process, of the exponential martingales used in the study of random walks or of Brownian motion.
On a Class of Distributions Stable Under Random Summation
Authors: Klebanov L. B. , Kakosyan A. V. , Rachev S. T. , Temnov G.
Published: June 2012

We study a family of distributions that satisfy the stability-under-addition property, provided that the number ν of random variables in a sum is also a random variable. We call the corresponding property ν-stability and investigate the situation when the semigroup generated by the generating function of ν is commutative. Using results from the theory of iterations of analytic functions, we describe ν-stable distributions generated by summations with rational generating functions. A new case in this class of distributions arises when generating functions are linked with Chebyshev polynomials. The analogue of normal distribution corresponds to the hyperbolic secant distribution.
A Note on the Failure Rates in Finite Mixed Populations
Authors: Cha Ji Hwan , Giorgio Massimiliano
Published: June 2012

Almost all populations existing in the real world are finite populations. Specifically, in the areas relevant to lifetime modeling and analysis, finite populations are frequently encountered. However, descriptions of failure/survival patterns of elements in the finite population have not yet been properly established. In particular, it is questionable whether the ordinary failure rate can be defined for finite populations in the same way and whether the corresponding interpretations are still valid. In this paper we consider two kinds of finite mixed population and provide new definitions for their failure rates. Then we clarify the notion of failure rate in finite populations.
Two-Dimensional Signatures
Authors: Gertsbakh Ilya , Shpungin Yoseph , Spizzichino Fabio
Published: June 2012

The notion of the signature is a basic concept and a powerful tool in the analysis of networks and reliability systems of binary type. An appropriate definition of this concept has recently been introduced for systems that have ν possible states (with ν ≥ 3). In this paper we analyze in detail several properties and the most relevant aspects of such a general definition. For simplicity's sake, we focus our attention on the case ν = 3. Our analysis will however provide a number of hints for understanding the basic aspects of the general case.
An Inverse Gamma Activity Time Process with Noninteger Parameters and a Self-Similar Limit
Authors: Finlay Richard , Seneta Eugene , Wang Dingcheng
Published: June 2012

We construct a process with inverse gamma increments and an asymptotically self-similar limit. This construction supports the use of long-range-dependent t subordinator models for actual financial data as advocated in Heyde and Leonenko (2005), in that it allows for noninteger-valued model parameters, as is found empirically in model estimation from data.
Exact-Order Asymptotic Analysis for Closed Queueing Networks
Authors: George David K. , Xia Cathy H. , Squillante Mark S.
Published: June 2012

In this paper we study the asymptotic behavior of a general class of product-form closed queueing networks as the population size grows large. We first characterize the asymptotic behavior of the normalization constant for the stationary distribution of the network in exact order. This result then enables us to establish the asymptotic behavior of the system performance metrics, which extends a number of well-known asymptotic results to exact order. We further derive new, computationally simple approximations for performance metrics that significantly improve upon existing approximations for large-scale networks. In addition to their direct use for the analysis of large networks, these new approximations are particularly useful for reformulating large-scale queueing network optimization problems into more easily solvable forms, which we demonstrate with an optimal capacity planning example.
A Central Limit Theorem for a Discrete-Time SIS Model with Individual Variation
Authors: McVinish R. , Pollett P. K.
Published: June 2012

A discrete-time SIS model is presented that allows individuals in the population to vary in terms of their susceptibility to infection and their rate of recovery. This model is a generalisation of the metapopulation model presented in McVinish and Pollett (2010). The main result of the paper is a central limit theorem showing that fluctuations in the proportion of infected individuals around the limiting proportion converges to a Gaussian random variable when appropriately rescaled. In contrast to the case where there is no variation amongst individuals, the limiting Gaussian distribution has a nonzero mean.
On Optimal Stopping Problems for Matrix-Exponential Jump-Diffusion Processes
Authors: Sheu Yuan-Chung , Tsai Ming-Yao
Published: June 2012

In this paper we consider optimal stopping problems for a general class of reward functions under matrix-exponential jump-diffusion processes. Given an American call-type reward function in this class, following the averaging problem approach (see, for example, Alili and Kyprianou (2005), Kyprianou and Surya (2005), Novikov and Shiryaev (2007), and Surya (2007)), we give an explicit formula for solutions of the corresponding averaging problem. Based on this explicit formula, we obtain the optimal level and the value function for American call-type optimal stopping problems.
Sample Path Optimal Policies for Serial Lines with Flexible Workers
Authors: Pandelis Dimitrios G. , Van Oyen Mark P.
Published: June 2012

We study the dynamic assignment of cross-trained workers in serial production lines characterized by stochastic process times and inventory buffers between stations. Throughput maximization is the objective. Each worker is trained for a subset of tasks, where emphasis is placed on systems with each worker trained for a zone of stations with stations near the zone boundaries being served (shared) by one or more other workers as well. Using sample path comparisons, we identify structural properties of optimal worker allocation policies. We identify when (i) a worker can prioritize the job in the most downstream station (last-buffer-first-served), and (ii) only the downstream (as opposed to upstream) server should serve a single task.
The COP9 signalosome, cullin 3 and Keap1 supercomplex regulates CHOP stability and adipogenesis
Authors: Huang Xiaohua , Ordemann Jürgen , Müller Joachim M. , Dubiel Wolfgang
Published: June 2012

Obesity is one of the most serious health problems of the 21st century. It is associated with highly increased risk of type 2 diabetes, high blood pressure, cardiovascular disease as well as several cancers. The expansion of the fat tissue needs the differentiation of preadipocytes to adipocytes, a process called adipogenesis. Dysfunction of adipogenesis is a hallmark of obesity and delineation of underlying mechanisms has high priority for identifying targets for pharmacological intervention. Here we investigate the impact of the COP9 signalosome (CSN), a regulator of cullin-RING ubiquitin ligases (CRLs), and of C/EBP homologous protein (CHOP) on the differentiation of LiSa-2 preadipocytes. CHOP induced by piceatannol or by permanent overexpression in LiSa-2 cells blocks adipocyte differentiation as characterized by inhibited fat droplet formation and vascular endothelial growth factor (VEGF) production. Knockdown of the CSN by permanent downregulation of CSN1 in LiSa-2 cells elevates CHOP and retards adipogenesis. The effect of the CSN knockdown on CHOP stability can be explained by the protection of the CRL component Keap1 by the CSN associated ubiquitin-specific protease 15 (USP15). Pulldowns and glycerol gradients reveal that CHOP interacts with a supercomplex consisting of the CSN, cullin 3 and Keap1. Transient knockdown of Keap1 increases CHOP steady state level and retards its degradation. We conclude that CHOP stability is controlled by a CSN-CRL3Keap1 complex, which is crucial for adipogenesis. Our data show that CHOP is a distinguished target for pharmacological intervention of obesity.
The endocytic adapter E-Syt2 recruits the p21 GTPase activated kinase PAK1 to mediate actin dynamics and FGF signalling
Authors: Jean Steve , Tremblay Michel G. , Herdman Chelsea , Guillou François , Moss Tom
Published: June 2012

Fibroblast growth factor (FGF) signalling plays an essential role in early vertebrate development. However, the response to FGF requires endocytosis of the activated FGF receptor (FGFR) that is in part dependent on remodelling of the actin cytoskeleton. Recently we showed that the extended synaptotagmin family plasma membrane protein, E-Syt2, is an essential endocytic adapter for FGFR1. Here we show E-Syt2 is also an interaction partner for the p21-GTPase Activated Kinase PAK1. The phospholipid binding C2C domain of E-Syt2 specifically binds a site adjacent to the CRIB/GBD of PAK1. PAK1 and E-Syt2 selectively complex with FGFR1 and functionally cooperate in the FGF signalling. E-Syt2 binding suppresses actin polymerization and inhibits the activation of PAK1 by the GTPases Cdc42 and Rac. Interestingly, the E-Syt2 binding site on PAK1 extensively overlaps a site recently suggested to bind phospholipids. Our data suggest that PAK1 interacts with phospholipid membrane domains via E-Syt2, where it may cooperate in the E-Syt2-dependent endocytosis of activated FGFR1 by modulating cortical actin stability.
Intermediated Blind Portfolio Auctions
Authors: Padilla Michael , Van Roy Benjamin
Published: June 2012

As much as 12%% of the daily volume on the New York Stock Exchange, and similar volumes on other major world exchanges, involves sales by institutional investors to brokers through blind portfolio auctions. Such transactions typically take the form of a first-price sealed-bid auction in which the seller engages a few potential brokers and provides limited information about the portfolio being sold. Uncertainty about the portfolio contents reduces bids, effectively increasing the transaction cost paid by the seller. We consider the use of a trusted intermediary or equivalent cryptographic protocol to reduce transaction costs. In particular, we propose a mechanism through which each party provides relevant private information to an intermediary who ultimately reveals only the portfolio contents and price paid, and only to the seller and winning broker. Through analysis of a game-theoretic model, we demonstrate substantial potential benefits to sellers. For example, under reasonable assumptions a seller can reduce expected transaction costs by more than 10%.

This paper was accepted by Wei Xiong, finance.
Product Market Efficiency: The Bright Side of Myopic, Uninformed, and Passive External Finance
Authors: Noe Thomas H. , Rebello Michael J. , Rietz Thomas A.
Published: June 2012

We model the effect of external financing on a firm's ability to maintain a reputation for high-quality production. Producing high quality is first best. Defecting to low quality is tempting because it lowers current costs while revenue remains unchanged because consumers and outside investors cannot immediately observe the defection. However, defection to low quality impairs the firm's reputation, which lowers cash flows and inhibits production over the long term. Financing via short-term claims discourages defection to low quality because the gains from defection are mostly captured by outside investors through an increase in the value of their claims. Therefore, if the firm relies on short-term external financing, it is more likely to produce over the long run, produce high-quality goods, and enjoy high profitability. The aggregate results from a laboratory experiment generally accord with these predictions.

This paper was accepted by Brad Barber, finance.
The Timbre of Thai Classical Singing
Authors: Latartara John
Published: June 2012

This article explores the timbre of Thai classical singing with an emphasis on uan, a wordless vocalization based upon specific vowels and consonants, using spectrographic images. Spectrographs are computer images that visualize the fundamental, overtones, and noise-like sounds of a performance. Uan can be reduced to five basic sounds and are analyzed individually and then placed within a musical context. Performances from different generations and musical lineages are contrasted and compared in relation to timbre. I argue it is the relative timbral consistency of the five basic uan sounds, connecting musical generations and lineages, combined with the unique characteristics of each performance that defines the distinct sound of Thai classical singing.