bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalized Finite Difference Time Domain Method and Its Application to Acoustics
Authors: Wei Jianguo , Wang Song , Hou Qingzhi , Dang Jianwu
Published: June 2015

A meshless generalized finite difference time domain (GFDTD) method is proposed and applied to transient acoustics to overcome difficulties due to use of grids or mesh. Inspired by the derivation of meshless particle methods, the generalized finite difference method (GFDM) is reformulated utilizing Taylor series expansion. It is in a way different from the conventional derivation of GFDM in which a weighted energy norm was minimized. The similarity and difference between GFDM and particle methods are hence conveniently examined. It is shown that GFDM has better performance than the modified smoothed particle method in approximating the first- and second-order derivatives of 1D and 2D functions. To solve acoustic wave propagation problems, GFDM is used to approximate the spatial derivatives and the leap-frog scheme is used for time integration. By analog with FDTD, the whole algorithm is referred to as GFDTD. Examples in one- and two-dimensional domain with reflection and absorbing boundary conditions are solved and good agreements with the FDTD reference solutions are observed, even with irregular point distribution. The developed GFDTD method has advantages in solving wave propagation in domain with irregular and moving boundaries.
Feasibility and Impact of a Combined Supervised Exercise and Nutritional-Behavioral Intervention following Bariatric Surgery: A Pilot Study
Authors: Jassil Friedrich C. , Manning Sean , Lewis Neville , Steinmo Siri , Kingett Helen , Lough Fiona , Pucci Andrea B. F. , Cheung W. H. , Finer Nicholas , Walker Judith , Doyle Jaqueline , Batterham Rachel L.
Published: June 2015

Background.Lifestyle intervention programs after bariatric surgery have been suggested to maximise health outcomes. This pilot study aimed to investigate the feasibility and impact of an 8-week combined supervised exercise with nutritional-behavioral intervention following Roux-en-Y gastric bypass and sleeve gastrectomy.Methods.Eight female patients (44 ± 8 years old, BMI = 38.5 ± 7.2 kgm−2) completed the program. Before and after intervention, anthropometric measures, six-minute walk test (6MWT), physical activity level, eating behavior, and quality of life (QoL) were assessed. Percentage weight loss (%WL) outcomes were compared with a historical matched control group.Results.The program significantly improved functional capacity (mean increment in 6MWT was 127 ± 107 meters,p=0.043), increased strenuous intensity exercise (44 ± 49 min/week,p=0.043), increased consumption of fruits and vegetables (p=0.034), reduced consumption of ready meals (p=0.034), and improved “Change in Health” in QoL domain (p=0.039). The intervention group exhibited greater %WL in the 3–12-month postsurgery period compared to historical controls, 12.2 ± 7.5% versus 5.1 ± 5.4%, respectively (p=0.027).Conclusions.Lifestyle intervention program following bariatric surgery is feasible and resulted in several beneficial outcomes. A large randomised control trial is now warranted.
Arousal Predisposition as a Vulnerability Indicator for Psychosis: A General Population Online Stress Induction Study
Authors: Clamor Annika , Warmuth A. Malika , Lincoln Tania M.
Published: June 2015

Explanatory models ascribe to arousability a central role for the development of psychotic symptoms. Thus, a disposition to hyperarousal (i.e., increased arousal predisposition (AP)) may serve as an underlying vulnerability indicator for psychosis by interacting with stressors to cause symptoms. In this case, AP, stress-response, and psychotic symptoms should be linked before the development of a diagnosable psychotic disorder. We conducted a cross-sectional online study in a population sample (N=104;Mage=27.7years,SD=11.2, range 18–70). Participants rated their AP and subclinical psychotic symptoms. Participants reported their stress-levels before and after two stress inductions including an arithmetic and a social stressor. The participants with an increased AP generally felt more stressed. However, AP was not associated with the specific stress-response. As expected, positive psychotic symptoms were significantly associated with AP, but this was not mediated by general stress-levels. Its association to subtle, nonclinical psychotic symptoms supports our assumption that AP could be a vulnerability indicator for psychosis. The trait is easily accessible via a short self-report and could facilitate the identification of people at risk and be a promising target for early stress-management. Further research is needed to clarify its predictive value for stress-responses.
Stabilization of the FO-BLDCM Chaotic System in the Sense of Lyapunov
Authors: Zhou Ping , Bai Rongji , Cai Hao
Published: June 2015

Based on an integer-order Brushless DC motors (IO-BLDCM) system, we give a fractional-order Brushless DC motors (FO-BLDCM) system in this paper. There exists a chaotic attractor for fractional-order0.95<q≤1in the FO-BLDCM system. Furthermore, using the Lyapunov direct method for fractional-order system, a control scheme is proposed to stabilize the FO-BLDCM chaotic system in the sense of Lyapunov. Numerical simulation shows that the control scheme in this paper is valid for the FO-BLDCM chaotic system.
An Extended Assessment of Fluid Flow Models for the Prediction of Two-Dimensional Steady-State Airfoil Aerodynamics
Authors: Herbert-Acero José F. , Probst Oliver , Rivera-Solorio Carlos I. , Castillo-Villar Krystel K. , Méndez-Díaz Santos
Published: June 2015

This work presents the analysis, application, and comparison of thirteen fluid flow models in the prediction of two-dimensional airfoil aerodynamics, considering laminar and turbulent subsonic inflow conditions. Diverse sensitivity analyses of different free parameters (e.g., the domain topology and its discretization, the flow model, and the solution method together with its convergence mechanisms) revealed important effects on the simulations’ outcomes. The NACA 4412 airfoil was considered throughout the work and the computational predictions were compared with experiments conducted under a wide range of Reynolds numbers (7e5≤Re≤9e6) and angles-of-attack (-10°≤α≤20°). Improvements both in modeling accuracy and processing time were achieved by considering the RS LP-S and the Transition SST turbulence models, and by considering finite volume-based solution methods with preconditioned systems, respectively. The RS LP-S model provided the best lift force predictions due to the adequate modeling of the micro and macro anisotropic turbulence at the airfoil’s surface and at the nearby flow field, which in turn allowed the adequate prediction of stall conditions. The Transition-SST model provided the best drag force predictions due to adequate modeling of the laminar-to-turbulent flow transition and the surface shear stresses. Conclusions, recommendations, and a comprehensive research agenda are presented based on validated computational results.
Simulation of Cavitation Water Flows
Authors: Zamankhan Piroz
Published: June 2015

The air-water mixture from an artificially aerated spillway flowing down to a canyon may cause serious erosion and damage to both the spillway surface and the environment. The location of an aerator, its geometry, and the aeration flow rate are important factors in the design of an environmentally friendly high-energy spillway. In this work, an analysis of the problem based on physical and computational fluid dynamics (CFD) modeling is presented. The numerical modeling used was a large eddy simulation technique (LES) combined with a discrete element method. Three-dimensional simulations of a spillway were performed on a graphics processing unit (GPU). The result of this analysis in the form of design suggestions may help diminishing the hazards associated with cavitation.
Development of Fast-Time Stochastic Airport Ground and Runway Simulation Model and Its Traffic Analysis
Authors: Mori Ryota
Published: June 2015

Airport congestion, in particular congestion of departure aircraft, has already been discussed by other researches. Most solutions, though, fail to account for uncertainties. Since it is difficult to remove uncertainties of the operations in the real world, a strategy should be developed assuming such uncertainties exist. Therefore, this research develops a fast-time stochastic simulation model used to validate various methods in order to decrease airport congestion level under existing uncertainties. The surface movement data is analyzed first, and the uncertainty level is obtained. Next, based on the result of data analysis, the stochastic simulation model is developed. The model is validated statistically and the characteristics of airport operation under existing uncertainties are investigated.
Targeting Feeding and Eating Behaviors: Development of the Feeding Dynamic Intervention for Caregivers of 2- to 5-Year-Old Children
Authors: Eneli Ihuoma U. , Tylka Tracy L. , Watowicz Rosanna P. , Hummel Jessica , Ritter Jan , Lumeng Julie C.
Published: June 2015

Targeting feeding dynamics, a concept centered on the roles and interaction of the caregiver and child in a feeding relationship, may have significant potential for obesity intervention. The aim of this paper is to describe the 3-phase development of the Feeding Dynamics Intervention (FDI), an acceptability and feasibility study on implementing the feeding dynamic roles (Study 1), development of the FDI content (Study 2), and a pilot study on use of the 6-lesson FDI to promote behaviors consistent with a feeding dynamic approach (Study 3). Sample population was mothers with young children, 2–5 years old. An effect size (Hedges’g) greater than 0.20 was seen in more than half (57%) of maternal feeding behaviors, with the largest effect sizes (Hedges’g≥0.8) occurring with behaviors that represent the mother adopting her roles of determining what food is served, not using food as a reward, and not controlling her child’s intake. There was a significant decline in Pressure to Eat behaviors (2.9 versus 2.2,p<0.01) and Monitoring (4.1 versus 3.5,p<0.001). The FDI emerged as an acceptable and implementable intervention. Future studies need to investigate effects of the FDI on the child’s eating behaviors, self-regulation of energy intake, and anthropometrics.
MicroRNA-374b Suppresses Proliferation and Promotes Apoptosis in T-cell Lymphoblastic Lymphoma by Repressing AKT1 and Wnt-16
Authors: Qian Dong , Chen Kailin , Deng Haixia , Rao Huilan , Huang Huiqiang , Liao Yiji , Sun Xiaofei , Lu Suying , Yuan Zhiyong , Xie Dan , Cai Qingqing
Published: June 2015

Purpose: Deregulation of microRNA (miRNA) has been extensively investigated in both Hodgkin and non-Hodgkin lymphomas (NHL); however, little is known about the roles of miRNAs in T-cell lymphoblastic lymphoma (T-LBL). The aim of the present study was to investigate the potential roles of miR-374b in the development and treatment of T-LBL.

Experimental Design: MiRCURY LNA array was used to generate a miRNA-expressing profile. Real-time quantitative PCR and immunohistochemistry (IHC) were applied to detect the expression of miR-374b, AKT1, and Wnt16 in T-LBL samples. The dual-luciferase reporter assay was conducted to confirm target associations of miR-374b. The tumor-suppressive effect of miR-374b was determined by both in vitro and in vivo studies.

Results: The expression of 380 miRNAs was evaluated in five human T-LBL tissues and five infantile thymus samples by microRNA microarrays. Downregulation of miR-374b was frequently detected in primary T-LBL tissues, which was significantly associated with worse overall survival and increased risk of recurrence of the 58 patients enrolled in this study. miR-374b suppressed T-LBL cell proliferation in vitro and in vivo and sensitized cells to serum starvation- and chemotherapeutic agent-induced apoptosis. Furthermore, we characterized two AKT pathway–associated molecules, AKT1 and Wnt16, as direct targets of miR-374b. Consistently, in T-LBL patient tissues, AKT1 and Wnt16 expression was inversely correlated with miR-374b levels, and was an independent predictor of recurrence and survival.

Conclusions: Our data highlight the molecular etiology and clinical significance of miR-374b in T-LBL. Targeting miR-374b may represent a new therapeutic strategy to improve therapy and survival for T-LBL patients. Clin Cancer Res; 21(21); 4881–91. ©2015 AACR.
Omega-3-Acid Ethyl Esters Block the Protumorigenic Effects of Obesity in Mouse Models of Postmenopausal Basal-like and Claudin-Low Breast Cancer
Authors: Ford Nikki A. , Rossi Emily L. , Barnett Kelsey , Yang Peiying , Bowers Laura W. , Hidaka Brandon H. , Kimler Bruce F. , Carlson Susan E. , Shureiqi Imad , deGraffenried Linda A. , Fabian Carol J. , Hursting Stephen D.
Published: June 2015

Obesity induces chronic inflammation and is an established risk and progression factor for triple-negative breast cancers, including basal-like (BL) and claudin-low (CL) subtypes. We tested the effects of dietary supplementation with ethyl esters of the marine-derived anti-inflammatory omega-3 fatty acids eicosapentaenoic and docosahexaenoic acid (EPA+DHA; Lovaza) on growth of murine BL and CL mammary tumors. Female ovariectomized C57BL/6 mice were fed a control diet or a diet-induced obesity (DIO) diet with or without EPA+DHA (0.025%, resulting in blood levels of EPA and DHA comparable with women taking Lovaza 4 g/d) for 6 weeks. All mice were then orthotopically injected with Wnt-1 cells (a BL tumor cell suspension derived from MMTV-Wnt-1 transgenic mouse mammary tumors) or M-Wnt cells (a CL tumor cell line cloned from the Wnt-1 tumor cell suspension). Mice were killed when tumors were 1 cm in diameter. EPA+DHA supplementation did not significantly affect Wnt-1 or M-Wnt mammary tumor growth in normoweight control mice. However, EPA+DHA supplementation in DIO mice reduced growth of Wnt-1 and M-Wnt tumors; reduced leptin:adiponectin ratio and proinflammatory eicosanoids in the serum; improved insulin sensitivity; and decreased tumoral expression of COX-2 and phospho-p65. Thus, EPA+DHA supplementation in mouse models of postmenopausal BL and CL breast cancer offsets many of the protumorigenic effects of obesity. These preclinical findings, in combination with results from parallel biomarker studies in women, suggest that EPA+DHA supplementation may reduce the burden of BL and CL breast cancer in obese women. Cancer Prev Res; 8(9); 796–806. ©2015 AACR.
Effect of Combined Treatment with Ursolic Acid and Resveratrol on Skin Tumor Promotion by 12-O-Tetradecanoylphorbol-13-Acetate
Authors: Cho Jiyoon , Rho Okkyung , Junco Jacob , Carbajal Steve , Siegel Dionicio , Slaga Thomas J. , DiGiovanni John
Published: June 2015

In this study, the effects of combining ursolic acid + resveratrol, for possible combined inhibitory effects on skin tumor promotion, were evaluated. Ursolic acid, resveratrol, and the combination of ursolic acid + resveratrol were applied topically prior to 12-O-tetracanoylphorbol-13-acetate (TPA) treatment on mouse skin to examine their effect on TPA-induced signaling pathways, epidermal hyperproliferation, skin inflammation, inflammatory gene expression, and skin tumor promotion. The combination of ursolic acid + resveratrol produced a greater inhibition of TPA-induced epidermal hyperproliferation. The combination of ursolic acid + resveratrol inhibited TPA-induced signaling pathways, including EGFR, STAT3, Src, Akt, Cox-2, Fas, NF-κB, p38 MAPK, c-Jun, and JNK1/2 while increasing levels of tumor suppressors, such as p21 and PDCD4, to a greater extent compared with the groups treated with the individual compounds. Ursolic acid + resveratrol also induced a dramatic increase of p-AMPK-αThr172. Combined treatment with ursolic acid + resveratrol resulted in a greater inhibition of expression of proinflammatory cytokines, including Il1a, Il1b, and Il22. Furthermore, NF-κB, Egr-1, and AP-1 DNA binding activities after TPA treatment were dramatically decreased by the combination of ursolic acid + resveratrol. Treatment with ursolic acid + resveratrol during skin tumor promotion with TPA produced greater inhibition of tumor multiplicity and tumor size than with either agent alone. Collectively, the greater ability of the combination of ursolic acid + resveratrol to inhibit skin tumor promotion was due to the greater inhibitory effects on growth factor and inflammatory signaling, skin inflammation, and epidermal hyperproliferation induced by TPA treatment. Cancer Prev Res; 8(9); 817–25. ©2015 AACR.
Treatment Time or Convection Volume in HDF: What Drives the Reduced Mortality Risk?
Authors: de Roij van Zuijdewijn Camiel L.M. , Nubé Menso J. , ter Wee Piet M. , Blankestijn Peter J. , Lévesque Renée , van den Dorpel Marinus A. , Bots Michiel L. , Grooteman Muriel P.C.
Published: June 2015

Background/Aims: Treatment time is associated with survival in hemodialysis (HD) patients and with convection volume in hemodiafiltration (HDF) patients. High-volume HDF is associated with improved survival. Therefore, we investigated whether this survival benefit is explained by treatment time. Methods: Participants were subdivided into four groups: HD and tertiles of convection volume in HDF. Three Cox regression models were fitted to calculate hazard ratios (HRs) for mortality of HDF subgroups versus HD: (1) crude, (2) adjusted for confounders, (3) model 2 plus mean treatment time. As the only difference between the latter models is treatment time, any change in HRs is due to this variable. Results: 114/700 analyzed individuals were treated with high-volume HDF. HRs of high-volume HDF are 0.61, 0.62 and 0.64 in the three models, respectively (p values <0.05). Confidence intervals of models 2 and 3 overlap. Conclusion: The survival benefit of high-volume HDF over HD is independent of treatment time.
Granulomatous Reaction to Pneumocystis jirovecii Diagnosed in a Bronchoalveolar Lavage: A Case Report
Authors: Nobile Antoine , Valenti Antonio , Aubert John-David , Beigelman Catherine , Letovanec Igor , Bongiovanni Massimo
Published: June 2015

Background: Granulomatous reaction to Pneumocystis jirovecii is a rare but well-known pathological finding encountered in the setting of immunosuppression, HIV infection being the most common cause. It can also potentially complicate the treatment of hematological malignancies, typically when drugs lowering the count and function of lymphocytes are used. Lung biopsy is considered the gold standard for the diagnosis of granulomatous P. jirovecii pneumonia, whereas the diffuse alveolar form is usually detected cytologically in bronchoalveolar lavage (BAL). Case: A female patient pursuing R-CHOP chemotherapy for the treatment of multiple hematological malignancies developed a rapidly progressing dyspnea. Chest CT scans revealed a worsening of a known infiltrative lung disease thought to be secondary to her chemotherapy. Alterations compatible with a drug-induced interstitial lung disease and well-formed focally necrotizing granulomas were observed on an open lung biopsy, but no microorganism was identified with special stains. Eventually, a granulomatous reaction to P. jirovecii was found in a BAL and allowed appropriate treatment with rapid improvement of the dyspnea. Conclusion: Because granulomas are tissue-bound structures, they are rarely described in BAL. This article describes the first reported cytological diagnosis of a granulomatous reaction to P. jirovecii and the potential diagnostic interest of such a peculiar finding.
Abrupt Intralesional Color Change on Dermoscopy as a New Indicator of Early Superficial Spreading Melanoma in a Japanese Woman
Authors: Sadayasu Anna , Tanaka Masaru , Maumi Yoshifumi , Ikeda Eriko , Sawada Mizuki , Ishizaki Sumiko , Murakami Yoshiyuki , Fujibayashi Mariko
Published: June 2015

Diagnosis of superficial spreading melanoma in the early stage is often difficult, even with dermoscopy. We report the case of a 37-year-old Japanese woman with superficial spreading melanoma in her left buttock. The lesion developed 20 years before becoming visible and gradually enlarged over the past few years without any symptoms. Physical examination showed a well-demarcated dark-brown macule 10 mm in diameter. Dermoscopy demonstrated a central dark area with a blue-grey structureless area, a milky-red area with irregular blue-grey dots or globules suggestive of regression structures, and multifocal black pigmentation with whitish scaly areas. An abrupt intralesional change in color from a central dark area to a peripheral light-brown area was also seen. The peripheral area showed an atypical pigment network with an obscure mesh and holes. Histopathologic examination of the lesion showed acanthosis with melanocytic proliferation and nuclear atypia, a band-like lymphocytic infiltrate, melanophages and a few nests of melanocytes just beneath the epidermis. The epidermal melanocytes were positive for S-100, Melan-A and HMB-45, but the dermal nests of melanocytes were negative for HMB-45 and positive for S-100 and Melan-A. A diagnosis of superficial spreading melanoma with a tumor thickness of 0.4 mm (pT1aN0M0, stage 1A) was established based on the clinical, dermoscopic and histopathologic findings. This case suggests that dermoscopy is useful in the diagnosis of this condition. An abrupt intralesional change of color might be a new indicator of early superficial spreading melanoma.
osce Principles: Which Principles?
Authors: Bloed Arie
Published: June 2015

The article explores the state of affairs of the basic principles of the Decalogue of Principles of the Helsinki Final Act of the osce after the violations of these principles by the Russian aggression against Ukraine. It gives an overview of the main features of the Decalogue as it was adopted in 1975 as well as more recent developments, in particular in relation to the non-intervention principle. Although several fundamental principles have been seriously violated, the author underlines the continued importance of the Decalogue and the need to make all efforts necessary to repair the amage.
The Geopolitics of European Security and Cooperation
Authors: Rojansky Matthew
Published: June 2015

At the present moment of obvious tension between Moscow and Washington, it may be tempting to dismiss the likelihood of progress on any diplomatic front, let alone in the complex multilateral format of the Organization for Security and Co-operation in Europe. Yet the 1972–75 Conference on Security and Cooperation in Europe (csce) itself took place against a backdrop of intense rivalry between the u.s. and Soviet-led blocs, suggesting that reasoned dialogue and consensus on core issues of shared security in the osce space is possible, despite—or perhaps even because of—the looming threat of conflict between geopolitical rivals. Despite some superficial similarities, relations between Russia and the United States today are sufficiently different from the past that they cannot accurately be described as a conflict in the same category as the Cold War. The u.s.-Russia relations have been severely strained over the crisis in Ukraine, but management of the crisis alone will not be enough to restore productive relations between Washington and Moscow or to repair the damage to European security. The best hope is likely a return to the principles of the 1975 Helsinki Final Act, and through a similarly inclusive region-wide dialogue. Today, the United States, Europe, and Russia all share an interest in renewal of just such a dialogue, although what will not—indeed what must not—return is the Cold War “balance of terror” that exerted pressure on all sides to participate seriously in the original Helsinki process.
The Low-Level Jet over the Southern Great Plains Determined from Observations and Reanalyses and Its Impact on Moisture Transport
Authors: Berg Larry K. , Riihimaki Laura D. , Qian Yun , Yan Huiping , Huang Maoyi
Published: June 2015

This study utilizes six commonly used reanalysis products, including the NCEP–Department of Energy Reanalysis 2 (NCEP2), NCEP Climate Forecast System Reanalysis (CFSR), ECMWF interim reanalysis (ERA-Interim), Japanese 25-year Reanalysis Project (JRA-25), Modern-Era Retrospective Analysis for Research and Applications (MERRA), and North American Regional Reanalysis (NARR), to evaluate features of the southern Great Plains low-level jet (LLJ) above the U.S. Department of Energy’s Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF) Southern Great Plains site. Two sets of radiosonde data are utilized: the six-week Midlatitude Continental Convective Clouds Experiment (MC3E) and a 10-yr period spanning 2001 through 2010. All six reanalyses are compared to MC3E data, while only the NARR, MERRA, and CFSR are compared to the 10-yr data. The reanalyses are able to represent most aspects of the composite LLJ profile, although there is a tendency for each reanalysis to overestimate the wind speed between the nose of the LLJ (at approximately 900 mb) and a pressure level of 700 mb. There are large discrepancies in the number of LLJs observed and derived from the reanalysis, particularly for strong LLJs, leading to an underestimate of the moisture transport associated with LLJs. When the 10-yr period is considered, the NARR and CFSR overestimate and MERRA underestimates the total moisture transport, but all three underestimate the transport associated with strong LLJs by factors of 1.4, 2.0, and 2.7 for CFSR, NARR, and MERRA, respectively. During MC3E there were differences in the patterns of moisture convergence and divergence, but the patterns are more consistent during the 10-yr period.
The Craft of Labormetrics
Authors: Hamermesh Daniel S.
Published: June 2015

Using a wide array of examples from the literature and from original estimates, the author examines the pitfalls that make good empirical research in labor economics at least as much craft as statistical technique. Among the subjects discussed are the appropriateness and cleanliness of data; problems of extreme observations; the validity of attempts to produce exogeneity using instrumental variables, “natural experiments,” and structural models; and the treatment of selectivity and unobservable individual effects. The author stresses the importance of testing empirical results to ensure that they make sense, and of presenting them clearly and economically.
Centralized Collective Bargaining and the Problem of ‘Compliance’: Lessons from the Italian Experience
Authors: Baccaro Lucio
Published: June 2015

According to the neo-corporatist approach to the “problem of compliance,” worker control over union policy is incompatible with centralized wage regulation, because only associations in which national leaders are insulated from their members are capable of delivering rank-and-file acceptance of wage moderation. This analysis of centralized collective bargaining agreements in Italy in the 1980s and 1990s provides a critical re-examination of the traditional neo-corporatist approach. The author, drawing on archival research and interviews, argues that centralization can be entirely compatible with decision-making procedures in which rank-and-file workers have ultimate decision-making power. In fact, the Italian labor movement's adoption of more “democratic” decision-making procedures, he claims, was instrumental in generating and sustaining centralized collective bargaining arrangements in Italy in the early 1990s.
Continuing Education, Job Training, and the Growth of Earnings Inequality
Authors: Marcotte Dave E.
Published: June 2015

Although it is well established that changes in the value of formal education can partly explain the increase in earnings inequality in the United States during the past three decades, less attention has been paid to the possible role of post-school training. Using data from cohorts of the National Longitudinal Surveys, the author finds that young men entering the labor market beginning in the late 1960s and those entering in the early 1980s differed little in the average incidence of training or earnings premiums associated with training, but further analysis shows that shifts in training favoring more educated workers can account for more than 40% of the observed increase in college-high school earnings differences among young men. Changing patterns of continuing learning do not, however, help explain the growth in earnings differences within equally educated groups.
Understanding Young Women's Marriage Decisions: The Role of Labor and Marriage Market Conditions
Authors: Blau Francine D. , Kahn Lawrence M. , Waldfogel Jane
Published: June 2015

Using the 1970, 1980 1990 Censuses, the authors investigate the impact of labor and marriage market conditions on the incidence of marriage of young women (age 16–24). They first estimate the effects on marriage of personal characteristics and Metropolitan Statistical Area (MSA) indicators, separately by race and education group. They then regress the first-stage MSA effects on MSA-level labor and marriage market conditions and welfare benefits, taking account of fixed effects and time trends specific to each MSA. Better female labor markets, worse female marriage markets worse male labor markets are found to lower marriage rates fr whites in all education groups. Results for these variables for blacks are sensitive to estimation technique, although stronger results are obtained for an older age group (25–34). While welfare benefits have a negative effect in cross-sectional analyses, the association becomes considerably weaker in fixed effects specifications.
Illegal Child Labor in the United States: Prevalence and Characteristics
Authors: Kruse Douglas L. , Mahony Douglas
Published: June 2015

Using the Current Population Survey, the National Longitudinal Survey, and other sources, the authors provide the first comprehensive estimates of the number of minors working in violation of federal and state child labor laws (working excessive hours or in hazardous occupations), their characteristics, their wages, and trends in illegal child labor. Although illegal employment of 15–17-year-olds has declined since the 1970s, some 154,000 minors are employed illegally in an average week, and 301,000 in a year. Illegal work hours total about 110 million per year. Whites, males, and 15-year-olds are the most likely to be working in violation of child labor laws. Youths working illegally in hazardous jobs earn, on average, $1.38 per hour less than legal young adults in the same occupations, which, combined with savings from employing youths for excessive hours, adds up to employer cost savings of roughly $136 million per year.
Effects of Work-Related Absences on Families: Evidence from the Gulf War
Authors: Angrist Joshua D. , Johnson John H.
Published: June 2015

The Gulf War provides an opportunity to estimate the effect of work-related separations on military families. Using data from the 1992 Survey of Officers and Enlisted Personnel, the authors estimate the effect of Gulf War deployment on divorce rates, spousal employment, and children's disability rates. Deployment of male soldiers had no effect on marital dissolution, though it did lead soldiers' wives to work less. In contrast, deployment of female soldiers led to a large and statistically significant increase in divorce rates, suggesting deployment of women placed a marked strain on marriages. Deployment of female soldiers did not affect husbands' labor supply. Finally, the results show no statistically significant increase in disability rates among the children of deployed personnel.
The Effect of Expanding Medicaid Eligibility on the Distribution of Children's Health Insurance Coverage
Authors: Shore-Sheppard Lara D.
Published: June 2015

Federal legislation passed in the late 1980s greatly expanded the Medicaid program to include children in families with incomes at and above the poverty threshold, regardless of family structure. Using March Current Population Survey data, the author evaluates how the expansions affected private and public insurance coverage levels across the income distribution. Estimates of the extent of take-up of public coverage and substitution of private coverage are used to generate distributions of coverage under two counterfactual situations: absence of expansions, and absence of substitution. The results indicate that the expansions had an equalizing effect on coverage levels across the lower five deciles of the income distribution between 1988 and 1995. In their absence, coverage would have fallen significantly in the third through fifth income deciles. Also, if all of the increased Medicaid enrollment had come from the uninsured population, inequality in coverage levels would have decreased even further.
Household Specialization and the Male Marriage Wage Premium
Authors: Hersch Joni , Stratton Leslie S.
Published: June 2015

Empirical research has consistently shown that married men have substantially higher wages, on average, than otherwise similar unmarried men. One commonly cited hypothesis to explain this pattern is that marriage allows one spouse to specialize in market production and the other to specialize in home production, enabling the former—usually the husband—to acquire more market-specific human capital and, ultimately, earn higher wages. The authors test this hypothesis using panel data from the National Survey of Families and Households. The data reveal that married men spent virtually the same amount of time on home production as did single men, albeit on different types of housework. Estimates from a fixed effects wage equation indicate that the male marriage wage premium is not substantially affected by controls for home production activities. Household specialization, the authors conclude, does not appear to have been responsible for the marriage premium in this sample.
Male/Female Earnings Differences in Self-Employment: The Effects of Marriage, Children, and the Household Division of Labor
Authors: Hundley Greg
Published: June 2015

Data from the National Longitudinal Study of the High School Class of 1972 and the Panel Study of Income Dynamics are used to investigate reasons for the gender earnings gap among the self-employed. Compared to organizational employment, self-employment may allow workers freer adjustment of work effort in response to changing needs for market work income and household production. Consistent with that hypothesis, the analysis shows that self-employed women's earnings declined with marriage, family size, and hours of housework, whereas self-employed men's earnings increased with marriage and family size. Organizationally employed workers' earnings exhibited a similar but less pronounced pattern, suggesting that in the self-employment sector the structure of female/male relative earnings was more sensitive to family size and composition. Self-employed women and men specialized more intensively in housework and market work, respectively. Women apparently tended to choose self-employment to facilitate household production, and men to achieve higher earnings.
Multi-Level Bargaining during Bulgaria's Return to Capitalism
Authors: Iankova Elena A.
Published: June 2015

This paper emphasizes the close interrelatedness among various levels of bargaining in transition economies. Focusing on the Bulgarian case, the author argues that in Bulgaria and other transition economies, neither purely national nor purely company-based bargaining is occurring; instead, the “social partners” (interest groups representing labor and business) have developed a multi-level bargaining structure that encompasses and links together national, company, industry, and regional levels. Multi-tier bargaining is prompted, on the one hand, by simultaneous pressures for centralization and decentralization during economic restructuring, and, on the other, by the need to legitimate the social partners at all levels. The author shows that in Bulgaria, increasing interdependencies and interactions among levels of bargaining have helped secure greater flexibility, adaptability, and survivability during extremely uncertain times.
Community College Enrollment, College Major, and the Gender Wage Gap
Authors: Gill Andrew M. , Leigh Duane E.
Published: June 2015

The literature on the narrowing of the gender wage gap during the 1980s considers, among other factors, the closing of the male-female differential in post-secondary education. This paper looks specifically at the role played by the dramatic relative increase in women's enrollment in two-year colleges. With independent cross-sections developed using NLSY data, the authors find that the gender wage gap narrowed by 0.0469 log points between 1985 and 1990 and by 0.0932 log points between 1989 and 1994. The more pronounced decrease observed for 1989–94 is largely explained by erosion of male-female differences in weeks worked, job tenure, and full-time employment. A more novel finding is evidence that while change in the quantity of education provides essentially no explanatory power, disaggregating education by two-year and four-year providers and by major field of study accounts for 8.5–11% of the closing of the wage gap over the 1989–94 period.
The Use of Flexible Staffing Arrangements in Core Production Jobs
Authors: Gramm Cynthia L. , Schnell John F.
Published: June 2015

Using data from their own 1994–96 survey of human resource managers in Alabama establishments, the authors investigate what determines the use of flexible staffing arrangements in core jobs and how such arrangements affect the job security provided to regular core employees. They find that union representation deterred in-house flexible arrangements, but not subcontracting; the likelihood of subcontracting was positively related to core employees' wages, relative to wages of other similar workers in the industry; and the use of flexible staffing arrangements was positively associated with two factors: core employee hiring costs, and a business strategy emphasizing low-cost production (versus, for example, market specialization). They also find evidence that regular core employees gained enhanced employment stability through their employer's use of flexible staffing arrangements to vary labor inputs in core jobs.
Immigration Reform and the Earnings of Latino Workers: Do Employer Sanctions Cause Discrimination?
Authors: Bansak Cynthia , Raphael Steven
Published: June 2015

Using the Current Population Surveys, the authors investigate whether sanctions against employers for hiring undocumented workers, a provision of the 1986 Immigration Reform and Control Act (IRCA), adversely affected the hourly earnings of Latino workers in the southwestern United States. The analysis exploits the fact that agricultural employers were exempt from the sanctions and from employee-verification requirements for the first two years following IRCA's passage. The authors find substantial pre-post IRCA declines in the wages of Latino non-agricultural workers relative to Latinos in agriculture. They do not observe similar shifts in the relative wages among non-Latino white workers. When using non-Latino black and white non-agricultural workers as alternative control groups, they find that Latino wages declined relative to black wages but not relative to white wages. Finally, they find that the pre-post IRCA inter-sectoral and inter-ethnic relative wage declines for Latino non-agricultural workers do not reflect longerterm trends.
The Effect of Unions on Wage Inequality in the U.S. Labor Market
Authors: Card David
Published: June 2015

This study uses Current Population Survey micro data for 1973–74 and 1993 to evaluate the effect of changing union membership on trends in male and female wage inequality. Unionization rates of men fell between the two sample periods, with bigger declines among lower skill groups. These trends account for 15–20% of the rise in male wage inequality. Union membership rates of low-wage women also declined, while unionization increased among higher-wage women. On balance, shifting unionization accounts for very little of the rise in female wage inequality. Economy-wide trends in unionization mask a sharp divergence between the private sector, where unionism was declining, and the public sector, where it was rising. Comparisons across sectors suggest that unionization substantially slowed the growth in wage inequality in the public sector.
Wage Effects of Unions and Industrial Councils in South Africa
Authors: Butcher Kristin F. , Rouse Cecilia Elena
Published: June 2015

Using data for 1995, the authors estimate union wage premia of about 20% for African workers and 10% for white workers in South Africa—roughly similar to estimates reported for other countries, including the United States. African nonunion workers who were covered by industrial council agreements received a premium of 6–10%; the premium was positive but not statistically significant for whites. Although the union/nonunion wage gap was smaller inside the industrial council system than outside it for Africans, the total union premium for union members covered by an industrial council agreement was similar to the union premium outside the industrial council system. Among Africans, the industrial council and union wage gaps were largest among low-wage workers. These findings, the authors conclude, do not support the common claim that a high union wage premium and the industrial council system are the primary causes of high unemployment in the South African labor market.
The Effects of Deregulation, De-Unionization, Technology, and Human Capital on the Work and Work Lives of Truck Drivers
Authors: Belman Dale L. , Monaco Kristen A.
Published: June 2015

The earnings of truck drivers fell by 21% between 1973 and 1995. Using Current Population Survey data, the authors find that deregulation accounted for one-third of the decline in drivers' wages, with a larger negative effect for non-union workers. Economic forces that broadly affected the blue-collar economy, proxied by the manufacturing wage, accounted for more than two-thirds of the decline. Finally, using unique survey data, the authors explore the effects of factors frequently cited as sources of blue-collar wage decline. This analysis indicates that only one new technology, satellite communication systems, had meaningful effects on drivers' earnings, which rose as a consequence of superior efficiency and work intensification. Union membership remains an important determinant of wages, with members earning 18% to 21% more than their non-union counterparts. The authors conclude that the primary sources of wage decline and increased wage inequality have been deregulation, de-unionization, and a declining manufacturing wage.
Do “High-Performance” Work Practices Improve Establishment-Level Outcomes?
Authors: Cappelli Peter , Neumark David
Published: June 2015

Studies of how different work practices affect organizational performance have suffered from methodological problems. Especially intractable has been the difficulty of establishing whether observed links are causal or merely reflect pre-existing differences among firms. This analysis uses a national probability sample of establishments, measures of work practices and performance that are comparable across organizations, and, most important, a unique longitudinal design incorporating data from a period prior to the advent of high-performance work practices. The conclusion most strongly supported by the evidence is that work practices transferring power to employees, often described as “high-performance” practices, raise labor costs per employee, suggesting that they may raise employee compensation. Higher compensation is a cost to employers, although some statistically weak evidence points to these practices raising productivity. The authors find little effect of high-performance work practices on overall labor efficiency, which they measure as the output per dollar spent on labor.
An Experimental Study of Job Evaluation and Comparable Worth
Authors: Arnault E. Jane , Gordon Louis , Joines Douglas H. , Phillips G. Michael
Published: June 2015

The doctrine of comparable worth rests on an assumption that each job possesses an inherent worth independent of the market forces of supply and demand. Implementation of comparable worth further requires that inherent job worth be measured with reasonable accuracy. This paper reports the results of an experimental study of comparable worth. Three commercial job evaluation firms rated the same set of 27 jobs in an actual company. Statistical analysis of the experimental data indicates that the three evaluators differed in which job trait, or constellation of traits, they used to evaluate inherent job worth, implying that at least one of them failed to measure inherent job worth accurately. These results suggest that any attempt to implement comparable worth may be quite sensitive to the evaluator chosen to measure job worth.
The Consequences of Doubling the Minimum Wage: The Case of Indonesia
Authors: Rama Martín
Published: June 2015

Indonesian minimum wages were tripled in nominal terms, and doubled in real terms, in the first half of the 1990s. The author analyzes data from the 1993 labor force survey to evaluate the effects of this hike on wage earnings and wage employment. The results suggest that the minimum wage hike had a modest impact on Indonesian labor market outcomes, increasing average wages by 5–15% and decreasing urban wage employment by 0–5%. The employment effects, however, varied substantially by firm size: small firms apparently experienced substantial decreases in employment, whereas some large firms actually saw their employment increase. Workers in those large firms, the author concludes, are the evident winners from the minimum wage hike.
The Willingness-to-Pay for Work/Family Policies: A Study of Teachers
Authors: Drago Robert , Costanza David , Caplan Robert , Brubaker Tanya , Cloud Darnell , Harris Naomi , Kashian Russell , Riggs T. Lynn
Published: June 2015

Recent evidence suggests that employers and employees may benefit from work/family policies and that even non-beneficiaries may support such policies. The authors posit that these policies generate not only “use” values (values for those who rely on them), but also, based on a particular norm of social justice, “need” values (values received by all individuals, regardless of expectations of direct benefit). Combining the median voter model with the contingent valuation method, which was designed to measure the willingness-to-pay for environmental goods such as national parks, the authors capture the willingness-to-pay for seven distinct work/family policies within a sample of 343 public, elementary school teachers. The results suggest that referenda to initiate work/family policies in exchange for payroll deductions from teachers would pass, depending on the specific deduction. Even respondents with no expectation of direct benefit may place a positive value on the policies, consistent with the notion of “need” values.
The Wealth of the Unemployed
Authors: Gruber Jonathan
Published: June 2015

Many studies have investigated the adequacy of unemployment insurance (UI) benefits as a form of income replacement, but few have looked at other resources with which the unemployed can finance their unemployment spells. This paper focuses on one form of resources, own wealth holdings. The author finds that the median worker's financial assets can cover roughly two-thirds of the income loss from an unemployment spell. Wealth holdings vary tremendously, however, and almost one-third of workers are unable to replace even 10% of their income loss. Moreover, predicted wealth holdings decline precipitously with realized unemployment durations, both absolutely and (especially) relative to actual income loss. This finding, together with the finding that individuals who are eligible for more generous UI draw down their wealth more slowly than do others during unemployment spells, suggests that UI benefit adequacy could be increased if the benefits were targeted to those with longer unemployment spells.