Agricultural labour adjustment and the impact of Institutions

The economic transformation in countries of Central and Eastern Europe as well as Asia resulted in a diverse picture of change in agricultural labour use. Based on a measure of sectoral labour adjustment, the paper explores the determinants of occupational labour flows paying special attention to the impact of institutions. Annual rates of occupational migration between agriculture and non-agriculture over the period 1978-2005 are calculated for a panel of 30 transition countries. Annual migration from agriculture ranges from outflows of nearly 8 percent of the agricultural labour force to immigration into agriculture about 9 percent on average. Fixed-effects panel models are used to explain the annual intersectoral labour flow. The most important determinants of the migration rate are the relative income differences between non-agricultural and agricultural sectors, the relative magnitude of agricultural labour, the development of terms of trade and the level of unemployment. Furthermore, the speed of economic reforms and the way of land privatization affect occupational migration significantly. An increasing intersectoral income difference points to still existing mobility restrictions for agricultural labour in some of the countries analyzed

Prospectus, October 11, 2017

Surgical Technology wins sixth consecutive merit award; RateMyProfessor.com a hit and miss with students; Adult tutoring program Project READ returns to Parkland; 2017 Flannel Fest flaunts fall festivities; Planetarium show puts our Violent Universe on display; Cobra soccer team win against ICC on Oct. 7https://spark.parkland.edu/prospectus_2017/1025/thumbnail.jp

Optical activation of germanium plasmonic antennas in the mid-infrared

Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas

Electromechanically Tunable Suspended Optical Nano-antenna

Coupling mechanical degrees of freedom with plasmonic resonances has potential applications in optomechanics, sensing, and active plasmonics. Here we demonstrate a suspended two-wire plasmonic nano-antenna acting like a nano-electrometer. The antenna wires are supported and electrically connected via thin leads without disturbing the antenna resonance. As a voltage is applied, equal charges are induced on both antenna wires. The resulting equilibrium between the repulsive Coulomb force and the restoring elastic bending force enables us to precisely control the gap size. As a result the resonance wavelength and the field enhancement of the suspended optical nano-antenna (SONA) can be reversibly tuned. Our experiments highlight the potential to realize large bandwidth optical nanoelectromechanical systems (NEMS)

Precipitated iron: a limit on gettering efficacy in multicrystalline silicon

A phosphorus diffusion gettering model is used to examine the efficacy of a standard gettering process on interstitial and precipitated iron in multicrystalline silicon. The model predicts a large concentration of precipitated iron remaining after standard gettering for most as-grown iron distributions. Although changes in the precipitated iron distribution are predicted to be small, the simulated post-processing interstitial iron concentration is predicted to depend strongly on the as-grown distribution of precipitates, indicating that precipitates must be considered as internal sources of contamination during processing. To inform and validate the model, the iron distributions before and after a standard phosphorus diffusion step are studied in samples from the bottom, middle, and top of an intentionally Fe-contaminated laboratory ingot. A census of iron-silicide precipitates taken by synchrotron-based X-ray fluorescence microscopy confirms the presence of a high density of iron-silicide precipitates both before and after phosphorus diffusion. A comparable precipitated iron distribution was measured in a sister wafer after hydrogenation during a firing step. The similar distributions of precipitated iron seen after each step in the solar cell process confirm that the effect of standard gettering on precipitated iron is strongly limited as predicted by simulation. Good agreement between the experimental and simulated data supports the hypothesis that gettering kinetics is governed by not only the total iron concentration but also by the distribution of precipitated iron. Finally, future directions based on the modeling are suggested for the improvement of effective minority carrier lifetime in multicrystalline silicon solar cells

Modelling the emergence of rodent filial huddling from physiological huddling

Huddling behaviour in neonatal rodents reduces the metabolic costs of physiological thermoregulation. However, animals continue to huddle into adulthood, at ambient temperatures where they are able to sustain a basal metabolism in isolation from the huddle. This 'filial huddling' in older animals is known to be guided by olfactory rather than thermal cues. The present study aimed to test whether thermally rewarding contacts between young mice, experienced when thermogenesis in brown adipose fat tissue (BAT) is highest, could give rise to olfactory preferences that persist as filial huddling interactions in adults. To this end, a simple model was constructed to fit existing data on the development of mouse thermal physiology and behaviour. The form of the model that emerged yields a remarkable explanation for filial huddling; associative learning maintains huddling into adulthood via processes that reduce thermodynamic entropy from BAT-metabolism and increase information about social ordering amongst littermates

The impact of sodium contamination in tin sulfide thin-film solar cells

Through empirical observations, sodium (Na) has been identified as a benign contaminant in some thin-film solar cells. Here, we intentionally contaminate thermally evaporated tin sulfide (SnS) thin-films with sodium and measure the SnS absorber properties and solar cell characteristics. The carrier concentration increases from 2 × 10[superscript 16] cm[superscript −3] to 4.3 × 10[superscript17] cm[superscript−3] in Na-doped SnS thin-films, when using a 13 nm NaCl seed layer, which is detrimental for SnS photovoltaic applications but could make Na-doped SnS an attractive candidate in thermoelectrics. The observed trend in carrier concentration is in good agreement with density functional theory calculations, which predict an acceptor-type Na[subscriptSn] defect with low formation energy.United States. Department of Energy (SunShot Initiative, Contract No. DE-EE0005329)National Science Foundation (U.S.) (Grant No. CHE-11115577)Alexander von Humboldt FoundationNational Science Foundation (U.S.). Graduate Research Fellowship ProgramMIT Energy Initiative (Fellowship)United States. Department of Energy. Office of Energy Efficiency and Renewable Energy (Postdoctoral Research Award)National Science Foundation (U.S.) (Award No. DMR-08-19762)National Science Foundation (U.S.). Center for Nanoscale Systems (Award No. ECS-0335765

Surface plasmon resonances in periodic and random patterns of gold nano-disks for broadband light harvesting

We analyze the localized surface plasmon resonance spectra of periodic square lattice arrays of gold nano-disks, and we describe numerically and experimentally the effect of disorder on resonance width, spectrum, and EM field enhancement in increasingly randomized patterns. The periodic structure shows a narrower and stronger extinction peak, conversely we observe an increase of up to (1-2) x 10(2) times enhancement as the disorder is gradually introduced. This allows for simpler, lower resolution fabrication, cost-effective in light harvesting for solar cell and sensing applications. We show that dipole-dipole interactions contribute to diffract light parallel to the surface as a mean of long-range coupling between the nano-disks. (C) 2012 Optical Society of Americ