bluuebunny/crossref_metadata_2025 huggingface dataset:
Explaining Changes in Organizational Form
Authors: Hanssen F. Andrew , Meehan James W. , Miceli Thomas J.
Published: May 2014

In this article, we investigate changes over time in the organization of the relationship between Major League Baseball and minor league baseball teams. We develop a model in which a minor league team serves two functions: talent development and local entertainment. The model predicts different modes of organizing the relationship between majors and minors based on the value of these parameters. We then develop a discursive history. Consistent with the model’s predictions, we find that when the value of minor league baseball’s training function was low but the value of its entertainment function was high, major and minor league franchises operated independently, engaging in arms’-length transactions. However, as the training function became more important and the local entertainment function less important, formal agreements ceded control of minor league functions to major league franchises. Finally, as the value of local entertainment rose once again in the late 20th century, the two roles were split, with control of local functions accruing to local ownership and training functions to major league teams. This analysis helps shed light on factors that influence the boundaries of the firm.
Undocumented Immigrants and Access to Health Care: Making a Case for Policy Reform
Authors: Edward Jean
Published: May 2014

The growth in undocumented immigration in the United States has garnered increasing interest in the arenas of immigration and health care policy reform. Undocumented immigrants are restricted from accessing public health and social service as a result of their immigration status. The Patient Protection and Affordability Care Act restricts undocumented immigrants from participating in state exchange insurance market places, further limiting them from accessing equitable health care services. This commentary calls for comprehensive policy reform that expands access to health care for undocumented immigrants based on an analysis of immigrant health policies and their impact on health care expenditures, public health, and the role of health care providers. The intersectional nature of immigration and health care policy emphasizes the need for nurse policymakers to advocate for comprehensive policy reform aimed at improving the health and well-being of immigrants and the nation as a whole.
Either Brain-Derived Neurotrophic Factor or Neurotrophin-3 Only Neurotrophin-Producing Grafts Promote Locomotor Recovery in Untrained Spinalized Cats
Authors: Ollivier-Lanvin Karen , Fischer Itzhak , Tom Veronica , Houlé John D. , Lemay Michel A.
Published: May 2014

Background. Transplants of cellular grafts expressing a combination of 2 neurotrophic factors, brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) have been shown to promote and enhance locomotor recovery in untrained spinalized cats. Based on the time course of recovery and the absence of axonal growth through the transplants, we hypothesized that recovery was due to neurotrophin-mediated plasticity within the existing locomotor circuitry of the lumbar cord. Since BDNF and NT-3 have different effects on axonal sprouting and synaptic connectivity/strengthening, it becomes important to ascertain the contribution of each individual neurotrophins to recovery. Objective. We studied whether BDNF or NT-3 only producing cellular grafts would be equally effective at restoring locomotion in untrained spinal cats. Methods. Rat fibroblasts secreting one of the 2 neurotrophins were grafted into the T12 spinal transection site of adult cats. Four cats in each group (BDNF alone or NT-3 alone) were evaluated. Locomotor recovery was tested on a treadmill at 3 and 5 weeks post-transection/grafting. Results. Animals in both groups were capable of plantar weight-bearing stepping at speed up to 0.8 m/s as early as 3 weeks and locomotor capabilities were similar at 3 and 5 weeks for both types of graft. Conclusions. Even without locomotor training, either BDNF or NT-3 only producing grafts promote locomotor recovery in complete spinal animals. More clinically applicable delivery methods need to be developed.
The Effect of Combined Somatosensory Stimulation and Task-Specific Training on Upper Limb Function in Chronic Stroke
Authors: Fleming Melanie K. , Sorinola Isaac O. , Roberts-Lewis Sarah F. , Wolfe Charles D. , Wellwood Ian , Newham Di J.
Published: May 2014

Background. Somatosensory stimulation (SS) is a potential adjuvant to stroke rehabilitation, but the effect on function needs further investigation. Objective. To explore the effect of combining SS with task-specific training (TST) on upper limb function and arm use in chronic stroke survivors and determine underlying mechanisms. Methods. In this double-blinded randomized controlled trial (ISRCTN 05542931), 33 patients (mean 37.7 months poststroke) were block randomized to 2 groups: active or sham SS. They received 12 sessions of 2 hours of SS (active or sham) to all 3 upper limb nerves immediately before 30 minutes of TST. The primary outcome was the Action Research Arm Test (ARAT) score. Secondary outcomes were time to perform the ARAT, Fugl-Meyer Assessment score (FM), Motor Activity Log (MAL), and Goal Attainment Scale (GAS). Underlying mechanisms were explored using transcranial magnetic stimulation stimulus–response curves and intracortical inhibition. Outcomes were assessed at baseline, immediately following the intervention (mean 2 days), and 3 and 6 months (mean 96 and 190 days) after the intervention. Results. The active group (n = 16) demonstrated greater improvement in ARAT score and time immediately postintervention (between-group difference; P < .05), but not at 3- or 6-month follow-ups ( P > .2). Within-group improvements were seen for both groups for ARAT and GAS, but for the active group only for FM and MAL ( P < .05). Corticospinal excitability did not change. Conclusions. Long-lasting improvements in upper limb function were observed following TST. Additional benefit of SS was seen immediately post treatment, but did not persist and the underlying mechanisms remain unclear.
Development of empirically based time-to-death curves for combat casualty deaths in Iraq and Afghanistan
Authors: D’Souza Edwin , Vickers Ross , Zouris James , Wing Vern , Galarneau Michael
Published: May 2014

The United States Department of Defense medical planners need survival-time estimates for anticipated patient streams associated with projected combat scenarios. Survival-time estimates should be grounded in empirical observations. Unfortunately, research in this domain has been limited to a single paper describing the development of died-of-wounds curves for combat casualties with life-threatening injuries. The curves developed from that research were based on a small dataset ( n = 160, with 26 deaths and 134 survivors) of forward surgical (Role II) casualties and subject matter experts’ judgments. This paper reports the first empirically based time-to-death curves for combat casualties based on a large sample. The results indicate that survival time varied across roles of care at which casualties died but was at most weakly associated with injury severity. Time-to-death curves were, therefore, developed for the overall study population of valid times to death and for Role I, Role II and Role III care. The log-logistic probability distribution provided the best representation of the survival times for the overall study population, while the log-normal distribution was the best choice for Role I, Role II and Role III care. The proposed time-to-death curves should refine the survival-time estimates used in combat medical logistics planning.
The Effects of Intraoperative Esmolol Administration on Perioperative Inflammatory Responses in Patients Undergoing Laparoscopic Gastrectomy
Authors: Kim Yongsuk , Hwang Wonjung , Cho Mi-La , Her Yang-Mi , Ahn Seulgi , Lee Jaemin
Published: May 2014

Background. Surgical trauma elicits inflammatory responses, including the secretion of cytokines. Recent studies demonstrated that beta-blockers could reduce the expression of cytokines after injury. We therefore tested the effects of different doses of intraoperative esmolol on the inflammatory response after surgery. Methods. Patients undergoing laparoscopic gastrectomy were randomly separated into 1 of 3 groups: saline, clinical dose, and subclinical dose groups. The levels of interleukin (IL)-6, IL-4, and IL-10 were quantified by sandwich enzyme-linked immunoassay after the induction of anesthesia (T0), at the end of peritoneal closure (T1), and 60 minutes after surgery (T2). Levels of C-reactive protein (CRP) were measured on postoperative day 1. Results. At T2, the levels of IL-6 and IL-10 in the saline group were elevated significantly compared with at T0 or T1 (IL-6: 119.62 and 15.97 pg/mL at T2 and T0, respectively [ P = .042]; IL-10: 27.27 and 7.03 pg/mL at T2 and T1, respectively [ P = .037]). However, no changes were observed over time in the clinical dose group. In contrast, postoperative levels of IL-4 were decreased significantly in the clinical dose group compared with the saline group (2.14 vs 21.91 pg/mL, P = .022). In addition, the CRP levels on postoperative day 1 were lower in the esmolol-treated groups, in a dose-dependent manner. Conclusions. Serum IL-6 and IL-10 levels were increased over time, suggesting that laparoscopic surgery is a stressor, even though it causes minimal tissue injury. Treatment with esmolol decreased the inflammatory response and CRP production in a dose-dependent manner.
College Information, Support, and Opportunities For All?
Authors: Martinez Melissa A.
Published: May 2014

In this case, 10 Latina/o high school seniors and one high school counselor share their perspectives on how college information and opportunities are distributed in their school. In doing so, it becomes evident that efforts are not systematic or equitable. As a result, dilemmas arise when some students are denied the opportunity to attend a college fair held off campus during the school day and find alternative means of doing so. Current and aspiring educational leaders are urged to consider the ethical, safety, and policy issues related to the immediate dilemmas and the larger concern regarding the school’s college-going culture.
Enterprising University Put to the Test
Authors: Fusilier Marcelline , Munro Douglas
Published: May 2014

Educational leaders are increasingly required to become effective change agents as schools and universities are faced with pressures to cut costs and adapt to stakeholder demands. This case details the administrative challenges of restructuring a private-sector higher education provider from a traditional to an enterprising university capable of making agile responses to promote its success. Focus is on a dean as change leader in the dynamic environment of transnational higher education in the Middle East.
Not All Tests Are Created Equal
Authors: O’Brien Jason , Winn Russell , Currier Kirsten
Published: May 2014

This case focuses on one parent’s request to have his daughter exempted from district-mandated computer tests (called STAR Enterprise tests). These tests are administered several times per year as a formative assessment to gauge student achievement in the areas of reading and math. The parent was concerned that the district was spending too much time testing and not enough time teaching students. The principal of the school and the Director of Assessment and Accountability for the district had to determine whether a parent’s wishes for his child superseded the mandate set forth by the State Department of Education with regard to gathering sufficient formative data to monitor and report student progress.
Transferring Leadership From Business to Education
Authors: Boncana Mohomodou
Published: May 2014

This case study is a narrative of four major leadership paradigms: managerial, transactional, transformational, and distributed leaderships. Understanding these leadership styles may help both practicing and prospective school leaders navigate better in the complex, dynamic, murky, and challenging waters of educational leadership. Furthermore, this case can serve as a valuable resource for practitioners who are striving to find solutions to the daily problems they are confronted with in their schools. Finally, the case may serve as a stepping stone to inform school leaders about the potential legal intricacies that the practice of their job may entail.
The Technology Principal
Authors: Anthony Anika Ball , Patravanich Supawaree
Published: May 2014

This case provides principal licensure candidates a strategic perspective on leading and managing educational technology initiatives. It presents issues related to vision setting, planning, implementation, organizational structure, and decision making. The case narrative is presented from the perspective of a principal, but it can also be used to prompt reflection from the perspective of a central office administrator such as a superintendent, assistant superintendent, technology director, or professional development coordinator. The case includes a preliminary knowledge-building activity and discussion questions, which, combined, prepare administrators to exercise technology leadership for school improvement through environmental scanning, organizational analysis, and performance measurement.
Gender and Status Offending
Authors: Spivak Andrew L. , Wagner Brooke M. , Whitmer Jennifer M. , Charish Courtney L.
Published: May 2014

This study examines the relationship between gender and juvenile justice processing outcomes for status offenders. The feminist criminological concept of judicial paternalism suggests that official justice systems, as gendered institutions with traditional patriarchal norms, will treat delinquent girls differently than delinquent boys. This paternalistic effect should be especially prevalent for status offenses, which are used to enforce institutional (parental, school, civic, parochial) authority. Using 1999-2001 juvenile processing data for 3,329 status offense referrals to the Oklahoma Office of Juvenile Affairs ( N = 3,329) and controlling for age, race, prior history, type of status offense, and measures of social class and urban environment, our results indicate that (a) girls outnumber boys among status offenders, (b) girls are more likely than boys to have their petitions filed for review, (c) girls are less likely than boys to be adjudicated guilty, and (d) girls are just as likely as boys to receive an incarcerated custody sentence as opposed to probation. We argue that these results illustrate the manifestation of the juvenile justice system as a gendered institution in which the adjudication of status offenders reflects judicial paternalism.
Inhibitory effect of adenosine on intimal hyperplasia and proliferation of smooth muscle cells in a carotid arterial anastomosis animal model
Authors: Albayrak Gokhan , Silistreli Erdem , Ergur Bekir , Kalkan Sule , Karabay Ozalp , Erdal A Cenk , Acikel Unal
Published: May 2014

Purpose

The effect of adenosine (9-β-0-ribifuranosyladenine) on the endothelial cell proliferation and neointimal hyperplasia is investigated in the rabbit carotid artery anastomosis model.

Methods

Twenty-eight New Zealand white rabbits were arranged in four groups of seven animals each. The right carotid arteries of each animal were transsected and re-anastomosed. The left sides remained as control. In Group A, no medication was used. In Group B, subcutaneous Adenosine was applied for 3 days. In Group C, the same dose was applied for 7 days, and in Group D for 21 days. After 28 days, the luminal diameters, luminal areas, intima/media ratios were all measured by using histopathological evaluation.

Findings

The mean luminal diameters and areas of the four groups were smaller than the control ones. Massive thickening of smooth muscle cell proliferation and dense intensifying in the connecting tissues were observed most prominently in Group A, in decreasing degrees within other groups. Intima/media ratio was highest in Group A. Scoring the quantity of e-NOS positive staining also revealed a significant difference between the experimental groups and their control associates.

Conclusion

The process of endothelial cell proliferation and neointimal hyperplasia can be significantly reduced by the use of adenosine.
Effect of crack and determination of fracture energy of carbon nanotube–reinforced polymer composites
Authors: Gupta Anand K , Harsha Suraj P
Published: May 2014

Carbon nanotube fillers in polymers are quite effective compared to traditional carbon black micro particles, primarily due to their high aspect ratios. Increasing attention is being focused on the carbon nanotube surface, namely, the interface between the carbon nanotube and the surrounding polymer matrix. From micromechanics, it is through shear stress build-up at this interface that stress is transferred from the matrix to the carbon nanotube. Because of the dissimilarity in elastic properties of polymer matrix and carbon nanotube, there will usually be some asymmetry near the crack tip even if the geometry and loading are symmetric and interface cracks tend to be mixed mode. In this article, the effect of crack on the interface of polymer matrix and carbon nanotube is analysed using both analytical and extended finite element method. The delamination is modelled as an interface crack problem and stress intensity factor and energy release rate is calculated as a function of crack length and stiffness ratio of matrix and carbon nanotube.
A comparison of projected and actual energy performance of buildings after thermal retrofit measures
Authors: Housez Pierre Pascal , Pont Ulrich , Mahdavi Ardeshir
Published: May 2014

This article addresses the discrepancies between projected and actual energy performance of thermally retrofitted buildings. Toward this end, we use detailed data and observations pertaining to seven residential buildings in Austria that were thermally retrofitted recently. These include five multifamily residences in Vorarlberg, the upper level of a duplex house in Lower-Austria, and a residential complex for the elderly in Styria. During the heating season 2009–2010 (1st October–30th April), indoor temperature and relative humidity levels were measured and logged in these buildings. For each building, the actual energy use during this period was derived based on bills for gas and electrical power. Additionally, we obtained and examined existing energy calculations (energy certificates) for these buildings. In six cases out of seven, we found a large discrepancy between projected and actual space heating demand. To explore possible reasons for this discrepancy, we generated for each of the buildings an energy certificate and performed detailed thermal simulations. Thereby, we took the main input parameters for energy calculations into consideration (air change rate, indoor air temperature, outside air temperature, and internal gains). If we use standard (default) values as suggested by Austrian standards for these parameters, the above-mentioned discrepancy cannot be explained. Measurements in the buildings, as well as interviews with the building’s inhabitants implied that standard-based input data assumptions were not reliable. A subsequent multi-factor study suggested that specifically the assumptions regarding air change rates might be responsible for the large deviations of the calculated values from the actual heating demand.
Physiotherapists use of and perspectives on the importance of patient-reported outcome measures for shoulder dysfunction
Authors: Payne Carol , Michener Lori A
Published: May 2014

Background

Many patient-reported outcome measures (PROs) for shoulder dysfunctions have acceptable psychometric properties. The present study examined current PRO usage and perceived importance.

Methods

Delegates at the 2010 International Congress of Shoulder and Elbow Therapists were invited to participate in this cross-sectional observational study. Research Electronic Data Capture (REDCap) web-based tools were used to design an online questionnaire, which was e-mailed to participants.

Results

Participants ( n = 101) reflected an 84% response rate. PRO use was considered ‘extremely’ or ‘very’ important by the majority of clinicians (76%) and researchers (98%). Most commonly used as a primary outcome by clinicians and researchers, respectively, were the Disabilities of the Arm Shoulder Hand Questionnaire (DASH) (40%, 44%) and the Oxford Shoulder Scale (OSS) (36%, 22%) and, as secondary outcomes, the DASH (33%, 28%), OSS (17%, 8%), the Shoulder Pain and Disability Index (SPADI) (8%,18%), and American Shoulder and Elbow Surgeons standardized assessment form (ASES) (8%, 13%). Psychometric properties were rated as ‘extremely’ or ‘very’ important by 86% to 96% of participants.

Conclusions

The majority of shoulder therapists consider PRO use to be very important and psychometric properties to be critical in PRO selection. The DASH, OSS, SPADI and ASES are most commonly used in clinical practice and research studies.
Biomechanical testing of a novel osteosynthesis plate for the ulnar coronoid process
Authors: Kiene Johannes , Bogun Jorn , Brockhaus Nina , Waizner Klaus , Schulz Arndt-Peter , Wendlandt Robert
Published: May 2014

Background

The present study aimed to biomechanically evaluate a novel locking plate intended for osteosynthesis of coronoid fracture compared to mini L-plates and cannulated screws.

Methods

Biomechanical tests were performed on a fracture model in synthetic bones. Three groups, each with eight implant-bone-constructs, were analyzed in quasi-static and dynamic tests. Finally, samples were tested destructively for maximum strength.

Results

The mean (SD) highest stiffness was measured for the novel plate [693 (18) N/mm], followed by the mini L-plate [646 (37) N/mm] and the cannulated screws [249 (113) N/mm]. During the cycling testing of the novel plate and the mini L-plate, no failures occurred, although three of the eight samples of cannulated screws failed during the test. The mean (SD) maximum strength during the destructive testing was 1333 (234) N for the novel plate, 1338 (227) N for the mini-L-plate and 459 (56) N for the cannulated screws. No statistical differences were found during the destructive testing between the two plates ( p = 0.999), although statistical differences were found between both plates and the cannulated screws ( p = 0.000 each).

Conclusions

Osteosynthesis of the coronoid process using the novel plate is mechanically similar to the mini L-plate. Both plates were superior to osteosynthesis with cannulated screws.
Capstan screw rotator cuff repair: a novel two-row mini-open technique
Authors: Guyver Paul , Goubran Alex , Jaques Aishling , Smith Christopher , Bunker Tim
Published: May 2014

Background

Prospective data collection occurred between 2000 and 2010 on 143 consecutive patients with symptomatic rotator cuff tears, aiming to examine the end-result of a new technique of mini-open double row repair: the Capstan screw technique.

Methods

All patients had a pre- and postoperative Oxford Shoulder Score (OSS), American Shoulder and Elbow Surgeons (ASES) score and range of movement measurements. All were followed up for a minimum of 1 year with an exit questionnaire. Subscapularis repairs, small (<1 cm) and massive (>5 cm) supraspinatus repairs were excluded. Ninety-nine patients fitted the inclusion and exclusion criteria of whom 87 had a complete data set.

Results

The mean (SD) pre-operative OSS was 21.85 (8.6) and the mean (SD) postoperative OSS was 44.58 (5.2) ( p < 0.0001). The mean (SD) pre-operative ASES score was 51.5 (19.4) and the mean (SD) postoperative ASES score was 86.42 (17.06) ( p < 0.0001). Flexion improved from a mean of 119° to 170° ( p < 0.0001). The clinical re-tear rate was 3.4% and the imaged re-tear rate was 6.8%. In total, 91% of patients were satisfied with the procedure. There were no deep infections and two (2%) minor wound infections. There was no single instance of deltoid dysfunction.

Conclusions

The Capstan screw technique represents a simple, rapid, strong and reliable mini-open technique.
Subscapularis Tears and Lesser Tuberosity Avulsion Fractures in the Pediatric Patient
Authors: LaMont Lauren E. , Green Daniel W. , Altchek David W. , Warren Russell F. , Wickiewicz Thomas L.
Published: May 2014

Background:

Pediatric subscapularis tears are known to be rare injuries. They are often associated with an avulsion fragment of the lesser tuberosity leading to dual description in the literature of either subscapularis tear or lesser tuberosity avulsion. Historically, they were managed nonoperatively; however, outcomes have improved with operative management. Nonoperative management often led to bony overgrowth at the lesser tuberosity that limited motion. The literature is limited to case reports and a few small case series, often not restricted to pediatric patients.

Study Design:

Case series.

Level of Evidence:

Level 5.

Methods:

Radiographic and operative databases were retrospectively reviewed to identify pediatric patients with subscapularis tears or lesser tuberosity avulsions in the past 10 years.

Results:

Five cases of pediatric subscapularis tears were identified that underwent operative management. Of the 5 cases, 4 had delayed presentation. In 1 case, the lesser tuberosity fragment was initially missed on radiographic imaging. All patients underwent operative management.

Conclusion:

These cases add to the body of knowledge of a rare pediatric injury that is commonly missed or diagnosis delayed. The importance of suspicion in the adolescent male patient without instability and unrelenting shoulder pain is stressed. Additionally, the importance of early magnetic resonance imaging with suspicion as well as an axillary view of the shoulder is demonstrated. As with all rare entities, it is important to disseminate information on natural history and interventions for this injury.
Toward a dynamic multilevel theory of team personality
Authors: Gardner Sharyn D. , Quigley Narda R.
Published: May 2014

Scholars have used a variety of ways to examine personality at the team level, yet never has a dynamic, multilevel approach been taken to examine the structure of team personality, how it develops, and how and why it may influence team effectiveness. If the concept of personality at the team level is to be taken seriously, we argue that a consistent theoretical orientation is necessary to synthesize past findings and guide future research. To fill this need, we discuss the definition, function, structure, and emergence of team personality, culminating in the development of a dynamic multilevel model linking individual team member personalities to team personality. This model is the basis through which we describe the development, path dependence, and impact of team personality. We conclude by discussing the theoretical and practical implications of our model.
A randomized trial of avatrombopag, an investigational thrombopoietin-receptor agonist, in persistent and chronic immune thrombocytopenia
Authors: Bussel James B. , Kuter David J. , Aledort Louis M. , Kessler Craig M. , Cuker Adam , Pendergrass Kelly B. , Tang Shande , McIntosh Joe
Published: May 2014

Key Points

Once-daily oral avatrombopag dose-dependently raised PCs over 28 days, with stable counts maintained over a 24-week extension. Low rates of severe AEs and study drug discontinuations due to AEs occurred despite dose increases in maintenance.
Transformation of ZnO polycrystalline sheets into hexagon-like mesocrystalline ZnO rods (tubes) under ultrasonic vibration
Authors: Ding Jianning , Fang Xiang , Yang Rong , Kan Biao , Li Xiazhang , Yuan Ningyi
Published: May 2014

The mesoscale assembly process is sensitive to additives that can modify the interactions of the crystal nucleus and the developing crystals with solid surfaces and soluble molecules. However, the presence of additives is not a prerequisite for the mesoscale transformation process. In this study, ZnO sheet networks were synthesized on Al foils by a hydrothermal process. Scanning electron microscopy and transmission electron microscopy images confirmed that under ultrasonic vibration, monolithic polycrystalline ZnO sheets transformed into hexagon-like mesocrystalline tubes or rods. The formation mechanism was discussed.
Microstructure and optical properties of nanocrystalline Cu2O thin films prepared by electrodeposition
Authors: Jiang Xishun , Zhang Miao , Shi Shiwei , He Gang , Song Xueping , Sun Zhaoqi
Published: May 2014

Cuprous oxide (Cu2O) thin films were prepared by using electrodeposition technique at different applied potentials (−0.1, −0.3, −0.5, −0.7, and −0.9 V) and were annealed in vacuum at a temperature of 100°C for 1 h. Microstructure and optical properties of these films have been investigated by X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), UV-visible (vis) spectrophotometer, and fluorescence spectrophotometer. The morphology of these films varies obviously at different applied potentials. Analyses from these characterizations have confirmed that these films are composed of regular, well-faceted, polyhedral crystallites. UV–vis absorption spectra measurements have shown apparent shift in optical band gap from 1.69 to 2.03 eV as the applied potential becomes more cathodic. The emission of FL spectra at 603 nm may be assigned as the near band-edge emission.
International migration desires related to subjective well-being
Authors: Cai Ruohong , Esipova Neli , Oppenheimer Michael , Feng Shuaizhang
Published: May 2014

Previous research on the determinants of international migration has largely focused on objective factors, such as income. We instead use subjective well-being (SWB) to explain international migration desires, an expressed willingness to migrate. We find that individuals with higher SWB have lower international migration desires. At the individual level, the SWB-migration relationship appears to be more robust than the income-migration relationship. At the country level, national average SWB better indicates international migration desires for rich countries, while income performs better for poor countries. We thus demonstrate the feasibility of employing subjective measures to study at least one aspect of an important social outcome, migration.

JEL codes

F22, O15, I31
A theoretical formalism for analyzing agent-based models
Authors: North Michael J
Published: May 2014

Purpose

Following Holland, complex adaptive systems (CASs) are collections of interacting, autonomous, learning decision makers embedded in an interactive environment. Modeling CASs is challenging for a variety of reasons including the presence of heterogeneity, spatial relationships, nonlinearity, and, of course, adaptation. The challenges of modeling CASs can largely be overcome by using the individual-level focus of agent-based modeling. Agent-based modeling has been used successfully to model CASs in many disciplines. Many of these models were implemented using agent-based modeling software such as Swarm, Repast 3, Repast Simphony, Repast for High-Performance Computing, MASON, NetLogo, or StarLogo. All of these options use modular imperative architectures with factored agents, spaces, a scheduler, logs, and an interface. Many custom agent-based models also use this kind of architecture. This paper’s contribution is to introduce and apply a theoretical formalism for analyzing modular imperative agent-based models of CASs. This paper includes an analysis of three example models to show how the formalism is useful for predicting the execution time and space requirements for representations of common CASs.

Method

The paper details the formalism and then uses it to prove several new findings about modular imperative agent-based models.

Results

It is proven that the asymptotic time and space performance of modular imperative agent-based modeling studies is computationally optimal for a common class of problems. Here ‘optimal’ means that no other technique can solve the same problem computationally using less asymptotic time or space. Modular imperative agent-based models are shown to be universal models, subject to the correctness of the Church-Turing thesis. Several other results are also proven about the time and space performance of modular imperative agent-based models. The formalism is then used to predict the performance of three models and the results are found to compare closely to the measured performance.

Conclusions

This paper’s contribution is to introduce, analyze, and apply a theoretical formalism for proving findings about agent-based models with modular agent scheduler architectures. Given that this kind of modeling is both computationally optimal and a natural structural match for many modeling problems, it follows that it is the best modeling method for such problems.
Retinoblastoma tumor suppressor pathway in breast cancer: prognosis, precision medicine, and therapeutic interventions
Authors: Witkiewicz Agnieszka K , Knudsen Erik S
Published: May 2014

A series of recent studies have demonstrated that the retinoblastoma tumor suppressor (RB) pathway plays a critical role in multiple clinically relevant aspects of breast cancer biology, spanning early stage lesions to targeted treatment of metastatic disease. In ductal carcinoma in situ, multiple groups have shown that dysregulation of the RB pathway is critically associated with recurrence and disease progression. Functional models have similarly illustrated key roles for RB in regulating epithelial–mesenchymal transition and other features contributing to aggressive disease. Invasive breast cancers are treated in distinct fashions, and heterogeneity within the RB pathway relates to prognosis and response to commonly used therapeutics. Luminal B breast cancers that have a poor prognosis amongst estrogen receptor-positive disease are defined based on the expression of RB-regulated genes. Such findings have led to clinical interventions that directly target the RB pathway through CDK4/6 inhibition which have promise in both estrogen receptor-positive and Her2-positive disease. In contrast, RB loss results in improved response to chemotherapy in triple-negative breast cancer, where ongoing research is attempting to define intrinsic vulnerabilities for targeted intervention. These findings support a wide-reaching impact of the RB pathway on disease that could be harnessed for improved clinical interventions.
3D frequency-domain finite-difference viscoelastic-wave modeling using weighted average 27-point operators with optimal coefficients
Authors: Gosselin-Cliche Benjamin , Giroux Bernard
Published: May 2014

Experimental data suggest that the viscoelastic behavior of rocks is more easily and accurately described in the frequency domain than in the time domain, supporting the idea of simulating seismic wave propagation in the frequency domain. We evaluated weighted-averaged 27-point finite-difference operators for 3D viscoelastic wave modeling in the frequency domain. Within the proposed framework, we developed general equations for normalized phase velocities that can be used with arbitrary finite-difference operators. Three sets of weighting coefficients for second-order central finite-difference operators that minimize the numerical dispersion for up to five grid points per wavelength were found using a damped least-squares (LS) criterion as well as a global optimization scheme based on [Formula: see text]- and [Formula: see text]-norm criteria. The three sets produced very similar dispersion curves, and improvement provided by global optimization appeared marginal in this respect. We also evaluated a discrete form for the heterogeneous formulation of the 3D viscoelastic equations with a perfectly match layer (PML). Heuristic performance assessment of frequency-dependent PML absorption coefficients provided a simple rule giving good results for eight PMLs at all frequencies. The proposed formalism was implemented with a massively parallel direct solver. Modeling results were compared with an analytic solution and a time-domain finite-difference code, and they gave good agreement when using LS and [Formula: see text]-norm optimal coefficients. On the other hand, [Formula: see text]-norm coefficients produced noisy results, indicating that minimizing the difference between analytic and numerical phase velocities, although necessary, is not a sufficient condition to guarantee low-numerical noise. Finally, analysis of the computational resources required to factorize the impedance matrix revealed that the memory complexity of the factorization is [Formula: see text] for an [Formula: see text] grid, compared to [Formula: see text] for the viscoacoustic case.
Non-invasive long-term fluorescence live imaging of Tribolium castaneum embryos
Authors: Strobl Frederic , Stelzer Ernst H. K.
Published: May 2014

Insect development has contributed significantly to our understanding of metazoan development. However, most information has been obtained by analyzing a single species, the fruit fly Drosophila melanogaster. Embryonic development of the red flour beetle Tribolium castaneum differs fundamentally from that of Drosophila in aspects such as short-germ development, embryonic leg development, extensive extra-embryonic membrane formation and non-involuted head development. Although Tribolium has become the second most important insect model organism, previous live imaging attempts have addressed only specific questions and no long-term live imaging data of Tribolium embryogenesis have been available. By combining light sheet-based fluorescence microscopy with a novel mounting method, we achieved complete, continuous and non-invasive fluorescence live imaging of Tribolium embryogenesis at high spatiotemporal resolution. The embryos survived the 2-day or longer imaging process, developed into adults and produced fertile progeny. Our data document all morphogenetic processes from the rearrangement of the uniform blastoderm to the onset of regular muscular movement in the same embryo and in four orientations, contributing significantly to the understanding of Tribolium development. Furthermore, we created a comprehensive chronological table of Tribolium embryogenesis, integrating most previous work and providing a reference for future studies. Based on our observations, we provide evidence that serosa window closure and serosa opening, although deferred by more than 1 day, are linked. All our long-term imaging datasets are available as a resource for the community. Tribolium is only the second insect species, after Drosophila, for which non-invasive long-term fluorescence live imaging has been achieved.
Multitasking in an eye: How the unusual organization of the principal larval eyes of Thermonectus marmoratus allows for far and near vision and might aid in depth perception
Authors: Stowasser Annette , Buschbeck Elke K.
Published: May 2014

Very few visual systems diverge fundamentally from the basic plans of well-studied animal eyes. However, investigating those that do can provide novel insights into visual system function. A particularly unusual system exists in the principal larval eyes of a visually guided aquatic predator, the Sunburst Diving Beetle, Thermonectus marmoratus (Coleoptera: Dystiscidae). These eyes are characterized by complex layered distal and proximal retinas. We previously reported that their principal eye E2 has a bifocal lens, and previous behavioral experiments suggested that these larvae have a unilateral range finding mechanism that may involve their bizarre eye organization. In our present study, we expanded our optical measurements and found that: 1) E1 also has a bifocal lens, 2) E1 is best suited for far vision while E2 is best suited for near vision and 3) throughout their typical hunting range, the positions of focused images shift across specific retinal layers. This anatomical and optical organization in principal could support unilateral range finding. Taken together, our findings outline an unusual visual mechanism that probably is essential for the extraordinary hunting ability of these larvae.
The spectral transmission of non-salticid spider corneas
Authors: Zhiyong Hu , Xu Xin , Chen Zhanqi , Li Hongze , Wang Xiaoyan , Wu Lingbing , Liu Fengxiang , Chen Jian , Li Daiqin
Published: May 2014

Although many salticid spiders have been shown to have corneas that transmit ultraviolet light (UV). Whether the corneas of non-salticid spiders transmit UV has not been previously investigated. In this study, we determined the spectral corneal transmission properties of 38 species belonging to 13 non-salticid families. We used these data to estimate the T50 transmission cut-off value, the wavelength corresponding to 50% maximal transmission for each species. The corneas of almost all species from the families Deinopidae, Lycosidae, Oxyopidae, Pisauridae, Sparassidae and Thomisidae, all of which have been reported to rely to a substantial extent on vision, transmitted short wavelengths below 400 nm, ranging from 306 to 381 nm. However, species from the families Atypidae and Ctenizidae are not known to rely substantially on vision, and the corneas of these species tended to absorb light of wavelengths below 380 nm, which may not allow UV sensitivity in these spiders. Liphistiidae, the family widely regarded as most basal among spiders, is of particular interest. The species in this family are not known to make substantial use of vision, and yet we found that liphistiid corneas transmitted UV light with a low T50 value (359 nm). T50 values of non-salticid spider corneas also varied with light habitat. Species living in dim environments tended to have UV-opaque corneas, but species inhabiting open areas had UV-transmitting corneas. However, there was no evidence of corneal transmission properties being related to whether a species is diurnal or nocturnal.
Effects of load magnitude, muscle length and velocity during eccentric chronic loading on the longitudinal growth of vastus lateralis muscle
Authors: Sharifnezhad Ali , Marzilger Robert , Arampatzis Adamantios
Published: May 2014

The present study investigated the longitudinal growth of the vastus lateralis (VL) muscle using four eccentric exercise protocols with different mechanical stimuli by modifying the load magnitude, lengthening velocity and muscle length at which the load is applied. Thirty-one participants voluntarily participated in this study in two experimental (EG) and one control group (CG). The first EG (n=10) exercised the knee extensors of one leg at 65% (low load magnitude) of the maximum isometric voluntary contraction (MVC) and the second leg at 100% MVC (high load magnitude) with 90°/s angular velocity, from 25° to 100° knee angle. The second EG (n=10) exercised one leg at 100% MVC, 90°/s, from 25° to 65° knee angle (short muscle length). The other leg was exercised at 100% MVC, 240°/s angular velocity (high muscle lengthening velocity) from 25° to 100°. In the pre-post measurements we examined the fascicle length of the VL at rest and the moment-angle relationship of the knee extensors. After 10 weeks of intervention we found a significant increase (~14%) of VL fascicle length compared to the CG, yet only in the leg that was exercised with high lengthening velocity. The findings provide evidence that not every eccentric loading causes an increase in fascicle length and that the lengthening velocity of the fascicles during the eccentric loading and particularly in the phase where the knee joint moment decreases (i.e. deactivation of the muscle) seems to be an important factor for longitudinal muscle growth.
Circadian rhythms are not involved in the regulation of circannual reproductive cycles in a sub-tropical bird, the spotted munia
Authors: Budki Puja , Malik Shalie , Rani Sangeeta , Kumar Vinod
Published: May 2014

Circannual rhythms regulate seasonal reproduction in many vertebrates. The present study investigated if circannual reproductive phenotypes (rhythms in growth of gonads and molt) were generated independently of the circadian clocks in the subtropical non-photoperiodic spotted munia (Lonchura punctulata). Birds were subjected to light-dark (LD) cycles with identical light but varying dark hours, such that the period of LD cycle (T) equaled to 16-(12L:4D), 21-(12L:9D), 24-(12L:12D) and 27-(12L:15D) hours, or to continuous light (LL, 24L:0D) at ~18°C. During ~21-month exposure, munia underwent at least two cycles of gonadal development and molt; changes in body mass were not rhythmic. This was similar to the occurrence of annual cycles in reproduction and molt observed in wild birds. A greater asynchrony between circannual cycles of gonad and molt indicated their independent regulation. Females showed reproductive rhythms with similar circannual periods, whilst in males circannual periods measured between peak gonadal size was longer in T21 and T24 than in the T16 or T27. This suggested a sex-dependent timing of annual reproduction in the spotted munia. Also, food availability periods may not influence the circannual timing of reproduction, as shown by the results on the rhythm in gonadal growth and regression in munia under T-photocycles and LL that provided differential light (feeding) hours. Further, a short-term experiment revealed that activity-rest pattern in munia were synchronized with T-photocycles, but were arrhythmic under LL. We conclude that circadian rhythms are not involved in the timing of the annual reproductive cycle in the spotted munia.
Brightness discrimination in the day- and night-adapted hunting spider Cupiennius salei
Authors: Campione Etienne , Schmid Axel
Published: May 2014

Cupiennius salei is a nocturnal spider with eight eyes which undergo a remarkable circadian cycle: the rhabdomeric membrane of the photoreceptor cells is dismantled during the day and rebuilt at the beginning of the night. Such drastic changes might influence the brightness discrimination ability. We tested this hypothesis by presenting square-shaped flickering stimuli with certain luminances on stationary backgrounds with other luminances, to spiders with day- or night-adapted eyes. When the spider, through its three pairs of so-called secondary eyes, perceives a visible contrast between the stimulus and the background, its principal eye muscle activity should increase. We therefore recorded this activity in vivo to assess the brightness discrimination ability of Cupiennius salei. Our results show that this spider has good brightness discrimination ability, which is significantly better with dark-adapted eyes. A Michelson contrast of 0.1 to 0.2 at night, and of 0.2 to 0.3 for day-adapted eyes, is sufficient to elicit a significant response, except below a critical value of luminance (≈ 16 cd/m2), where the minimal perceivable contrast needs to be higher. In the discussion we compare these performances with other animals, in particular with jumping spiders.
Molecular Wiring Method Based on Polymerization or Copolymerization of an Insulated π-Conjugated Monomer
Authors: Terao Jun , Homma Kyohei , Konoshima Yohei , Taniguchi Masateru , Kiguchi Manabu , Komoto Yuuki , Horikawa Masayo , Naito Yasuhisa , Fujihara Tetsuaki , Tsuji Yasushi
Published: May 2014

A new type of molecular wiring method was developed based on the polymerization or copolymerization of an insulated π-conjugated monomer between nanosized electrodes.