The impact of baby boomer retirements on teacher labor markets

This article explores the future of teacher labor markets. The authors find that teacher hiring needs will rise over the coming decade largely because of retirements. However, this increase will not be significantly different from that of past decades.Labor market ; Retirement

How will baby boomer retirements affect teacher labor markets?

The authors estimate teacher demand and supply through 2020 to gauge the impact of baby boomer retirements on the demand for new teachers. They find that the projected demand will accelerate through at least 2020, and a good portion of this increase will be due to retirements. Still, this demand, once it has been adjusted for the size of the potential work force, will not be considerably different from that of the past five decades.Retirement ; Labor market

E-business Adoption and the Use of Strategies in Small and Medium Enterprises: Suggestions for the Progression of SMEs' E-adoption

This paper presents a classification of SMEs according to their level of e-adoption and their use of formal strategies and e-business strategies. The five distinct groups established in this classification are described and suggestions for the progression of SMEs e-adoption are given

Descriptional complexity of pushdown store languages

It is well known that the pushdown store language P(M) of a pushdown automaton (PDA) M — i.e., the language consisting of words occurring on the pushdown along accepting computations of M — is a regular language. Here, we design succinct nondeterministic finite automata (NFA) accepting P(M). In detail, an upper bound on the size of an NFA for P(M) is obtained, which is quadratic in the number of states and linear in the number of pushdown symbols of M. Moreover, this upper bound is shown to be asymptotically optimal. Then, several restricted variants of PDA are considered, leading to improved constructions. In all cases, we prove the asymptotical optimality of the size of the resulting NFA. Finally, we apply our results to decidability questions related to PDA, and obtain solutions in deterministic polynomial time

Characterizing small-scale migration behavior of sequestered CO2 in a realistic geological fabric

For typical reservoir conditions, buoyancy and capillary forces grow dominant over viscous forces within a few hundred meters of the injection wells as the pressure gradient due to injection decreases, resulting in qualitatively different plume migration regimes. The migration regime depends on two factors: the capillary pressure of the leading edge of the plume and the range of threshold entry pressures within the rock at the leading edge of the plume. A capillary channel regime arises when these two factors have the same magnitude. Flow patterns within this regime vary from finger-like structures with minimal rock contact to back-filling structures with compact volumes of saturation distributed between fingers. Reservoir heterogeneity is one of the principal factors influencing CO2 migration pathway in the capillary channel regime. Here we characterize buoyancy-driven migration in a natural 2D geologic domain (1 m × 0.5 m peel from an alluvium) in which sedimentologic heterogeneity has been resolved at sub-millimeter (depositional) resolution. The relevant features of the heterogeneity are grain size distribution, which determines the mean and range of threshold pressures and correlation lengths of threshold pressures in horizontal and vertical directions. The relevant physics for this migration regime is invasion percolation, and simulations indicate that CO2 migrates through the peel in a few narrow pathways which cannot be captured by conventional coarse-grid simulations. The storage efficiency of the capillary channel regime would be low and consequently CO2 would also migrate greater distances than expected from models or simulations that neglect the capillary channel flow regime.Bureau of Economic Geolog

The Pan American (1968-02)

https://scholarworks.utrgv.edu/panamerican/1645/thumbnail.jp

Analytical investigation of dust, sludge and waste water specimens from the production facilities of a special glass manufacturer

Waste materials obtained at the production of special glasses need to be investigated for their constituents quickly, precisely, and sufficiently sensitivly in order that they can be recycled as raw materials to the batch, or that appropriate disposal measures can be initiated. The solid specimens from the environment, such as dust and sludge, are decomposed using mineral acids or alkali melts, while the waste waters in most of the cases are decomposed by means of HNO3/H2O2. In the event of high concentrations the elements are determined by mensuration analysis, while in the case of low (< 100 mg/l) and trace (< 0.1 mg/l) concentrations, induced coupled plasma spectrometry, atomic spectrometry in absorption (flame, graphite tube, hydride, and cold-vapour atomic absorption spectrometry) and in emission, respectively, and solvent spectrophotometry are employed

Improving ocean-glider's payload with a new generation of spectrophotometric PH sensor

Ocean gliders have clearly become nowadays useful autonomous platforms addressed to measure a wide range of seawater parameters in a more sustainable and efficient way. This new ocean monitoring approach has implied the need to develop smaller, faster and more efficient sensors without reducing key features like accuracy, resolution, time-response, among others, in order to fit the glider operational capabilities. This work is aiming to present the latest development stages of a new spectrophotometric pH sensor, its integration process into a Wave Glider SV3 platform and the preliminary results derived from an offshore mission performed in subtropical waters between the Canary Islands and Cape Verde archipelagos.Peer Reviewe