This paper investigates the effect of high‐skilled immigration on the wages of U.S.‐born college graduates. Descriptive evidence suggests that workers with different college majors compete in ...separate labor markets. Because immigrants are more likely than natives to study Science, Technology, Engineering, and Mathematics (STEM), a standard labor market model predicts that the relative wages of native STEM majors should fall as skilled immigration increases. Using an IV strategy that leverages large changes in the cap of H‐1B visas and controls for major‐ and age‐specific unobservable characteristics, I find that workers most exposed to increased competition from immigration have lower wages than one would expect. A 10‐percentage point increase in a skill group's immigrant‐native ratio decreases their relative wages by 1 percent. Overall, I estimate that the STEM wage premium decreased 4 to 12 percentage points from 1990 to 2010 because of immigration.
Heart failure with preserved ejection fraction, also referred to as diastolic heart failure, causes almost one-half of the 5 million cases of heart failure in the United States. It is more common ...among older patients and women, and results from abnormalities of active ventricular relaxation and passive ventricular compliance, leading to a decline in stroke volume and cardiac output. Heart failure with preserved ejection fraction should be suspected in patients with typical symptoms (e.g., fatigue, weakness, dyspnea, orthopnea, paroxysmal nocturnal dyspnea, edema) and signs (S3 heart sound, displaced apical pulse, and jugular venous distension) of chronic heart failure. Echocardiographic findings of normal ejection fraction with impaired diastolic function confirm the diagnosis. Measurement of natriuretic peptides is useful in the evaluation of patients with suspected heart failure with preserved ejection fraction in the ambulatory setting. Multiple trials have not found medications to be an effective treatment, except for diuretics. Patients with congestive symptoms should be treated with a diuretic. If hypertension is present, it should be treated according to evidence-based guidelines. Exercise and treatment by multidisciplinary teams may be helpful. Atrial fibrillation should be treated using a rate-control strategy and appropriate anticoagulation. Revascularization should be considered for patients with heart failure with preserved ejection fraction and coronary artery disease. The prognosis is comparable to that of heart failure with reduced ejection fraction and is worsened by higher levels of brain natriuretic peptide, older age, a history of myocardial infarction, and reduced diastolic function.
Temporary labor migration is an increasingly important mode of migration that generates substantial remittance flows, but raises important concerns for migrant well-being. The migration and health ...literature has seen a growing call for longitudinal, binational surveys that compare migrants to relevant non-migrant counterfactual groups in the sending country, in order to answer the basic question "Is migration good for health?" This study compares the health of male international migrants, internal migrants, and non-migrants using a unique representative panel survey of the Matlab subdistrict of Bangladesh.
A cohort of 5,072 respondents born 1958-1992 were interviewed in 1996-1997, and reinterviewed in 2012-2014. Extensive migrant follow-up yielded a 92% reinterview rate. We explored health and income outcomes for respondents who at the time of the follow-up interview were current international migrants (n = 790), returned international migrants (n = 209), internal migrants (n = 1,260), and non-migrants (n = 2,037). Compared to non-migrants, current international migrants were younger (mean 32.9 years versus 35.8 years), had more schooling (7.6 years versus 5.8 years), and were more likely to have an international migrant father (9.7% versus 4.0%) or brother (49.1% versus 30.3%). We estimated multivariate ordinary least squares and logistic regression models controlling for a wide range of control variables measured as far back as 1982. Results show that current international migrants had substantially better health status on factors that likely relate to self-selection such as grip strength and self-rated health. Current international migrants had no excess risk of injury in the past 12 months compared to non-migrants (adjusted mean risk = 6.0% versus 9.3%, p = 0.084). Compared to non-migrants, current international migrants had roughly twice the risk of overweight/obesity (adjusted mean risk = 51.7% versus 23.3%, p < 0.001), obesity (6.9% versus 3.4%, p = 0.012), and stage 1 or higher hypertension (13.0% versus 7.0%, p = 0.014). Compared to internal migrants, current international migrants had significantly higher levels of overweight/obesity (adjusted mean risk = 51.7% versus 37.7%, p < 0.001). Current international migrants showed above average levels of depressive symptoms on a 12-item standardized short-form Center for Epidemiologic Studies Depression Scale (+0.220 SD, 95% CI 0.098-0.342), significantly higher than internal migrants (-0.028 SD, 95% CI -0.111, 0.055; p < 0.001). Depressive symptoms differed significantly from those reported by non-migrants when restricting to items on negative emotions (international migrant score = 0.254 SD, non-migrant score = 0.056 SD, p = 0.004). Key limitations include the descriptive nature of the analysis, the use of both in-person and phone survey data for international migrants, the long recall period for occupational and mental health risk measures, and the coverage of a single out-migration area of origin.
In this study, we observed that international migrants had comparable or lower injury and mortality risks compared to respondents remaining in Bangladesh, due in part to the high risks present in Bangladesh. International migrants also showed higher levels of self-rated health and physical strength, reflective of positive self-selection into migration. They had substantially higher risks of overweight/obesity, hypertension, and depression. Negative health impacts may reflect the effects of both harsh migration conditions and assimilation into host population conditions. Our results suggest the need for bilateral cooperation to improve the health of guest workers.
This study lays a foundation for the design of the SH 0 plate acoustic wave (PAW) resonators based on LiNbO 3 plate, and are applicable to the ultra-wideband filters and next-generation tunable ...filters. The coupling coefficient (k 2 ) of SH 0 mode is optimized to as high as 55% and wideband spurious are well controlled by analyzing the propagation characteristics of plate modes in LiNbO 3 . The SH 0 mode is demonstrated to be slowly dispersive and features the superiority of interdigital transducer (IDT)-defining frequency over most other plate modes. On the device level, the transducer types and electrode materials are investigated and compared. In addition, for edge-reflected SH0 resonators, stopband dispersion analysis is provided and the longitudinal ripples are suppressed. For edge-reflected SH0 resonators, a novel perfect edge reflector is proposed with elimination of longitudinal spurious ripples.
Application of the finite-element method (FEM) for the simulation of surface acoustic wave (SAW) devices has been constrained by the large number of degrees of freedom required, resulting in large ...memory usage and long computation times. We propose a new 2-D algorithm that takes advantage of the periodic structure typical of SAW devices. The device is partitioned into small, repeatedly occurring building blocks. Only unique building blocks are simulated with FEM. The device geometry is presented as a hierarchical tree of cascading operations, where smaller blocks are combined into larger blocks. This is equivalent to the full FEM simulation of the device, implying the drastic reduction of memory consumption and simulation time for structures with a high degree of periodicity. The method is verified against FEM/BEM-based software. To ensure accurate and efficient simulation, the boundary conditions should be chosen according to the anisotropy of the substrate crystal.
Family planning programs are believed to have substantial long-term benefits for women's health and well-being, yet few studies have established either extent or direction of long-term effects. The ...Matlab, Bangladesh, maternal and child health/family planning (MCH/FP) program afforded a 12-y period of well-documented differential access to services. We evaluate its impacts on women's lifetime fertility, adult health, and economic outcomes 35 y after program initiation. We followed 1,820 women who were of reproductive age during the differential access period (born 1938-1973) from 1978 to 2012 using prospectively collected data from the Matlab Health and Demographic Surveillance System and the 1996 and 2012 Matlab Health and Socioeconomic Surveys. We estimated intent-to-treat single-difference models comparing treatment and comparison area women. MCH/FP significantly increased contraceptive use, reduced completed fertility, lengthened birth intervals, and reduced age at last birth, but had no significant positive impacts on health or economic outcomes. Treatment area women had modestly poorer overall health (+0.07 SD) and respiratory health (+0.12 SD), and those born 1950-1961 had significantly higher body mass index (BMI) in 1996 (0.76 kg/m
) and 2012 (0.57 kg/m
); fewer were underweight in 1996, but more were overweight or obese in 2012. Overall, there was a +2.5 kg/m
secular increase in BMI. We found substantial changes in lifetime contraceptive and fertility behavior but no long-term health or economic benefits of the program. We observed modest negative health impacts that likely result from an accelerated nutritional transition among treated women, a transition that would, in an earlier context, have been beneficial.
Kelvin probe force microscopy (KPFM) has been used to directly and quantitatively measure Hall voltages, developed at conducting tail-to-tail domain walls in ErMnO3 single crystals, when current is ...driven in the presence of an approximately perpendicular magnetic field. Measurements across a number of walls, taken using two different atomic force microscope platforms, consistently suggest that the active p-type carriers have unusually large room temperature mobilities of the order of hundreds of square centimeters per volt second. Associated carrier densities were estimated to be of the order of 1013 cm–3. Such mobilities, at room temperature, are high in comparison with both bulk oxide conductors and LaAlO3–SrTiO3 sheet conductors. High carrier mobilities are encouraging for the future of domain-wall nanoelectronics and, significantly, also suggest the feasibility of meaningful investigations into dimensional confinement effects in these novel domain-wall systems.
Local grassland restoration affects insect communities Luong, Justin C.; Turner, Patrick L.; Phillipson, Celina N. ...
Ecological entomology,
August 2019, 2019-08-00, 20190801, Letnik:
44, Številka:
4
Journal Article
Recenzirano
Odprti dostop
1. It is hypothesised that ecological restoration in
grasslands can induce an alternative stable state shift in vegetation. The change in vegetation influences insect community assemblages and allows ...for greater functional redundancy in pollination and refuge for native insect species.
2. Insect community assemblages at eight coastal California grassland sites were evaluated. Half of these sites had undergone restoration through active revegetation of native grassland flora and half were non‐restored. Insects were collected from Lupinus bicolor (Fabaceae) within 2 × 2‐m2 plots in spring 2017. Lupinus bicolor is a common native species that is used in California restoration projects, and home and state landscaping projects.
3. Ordination demonstrated that insect community assemblages were different between restored and non‐restored sites. These differences were seen in insect functional groups as well as taxa‐specific differences and were found to be driven by environmental characteristics such as non‐native forb cover.
4. Functional redundancy of herbivores decreased at restored sites, while pollinators became more redundant compared with non‐restored sites. The assemblages of the common species found at restoration sites contained more native insects than those found at non‐restored sites, including species such as Bombus vosnesenskii.
5. Local grassland restoration has the potential to induce an alternative stable state change and affect insect community assemblages. Additionally, it was found that grassland restoration can be a potential conservation tool to provide refugia for bumblebees (Bombus), but additional studies are required to fully understand its broader applicability.
Local grassland restoration alters the vegetation community, inducing an alternative stable state shift in the insect community assemblage.
Functional redundancy decreases for herbivores while increasing for pollinators in locally restored grasslands, as these sites can potentially provide refuge for native insect species.
The results demonstrate the applicability of stable state ecological theory to inform ecological restoration and show that restoration can be utilised to improve conservation efforts of a native bumblebee, Bombus vosnesenskii.
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