Energy consumption and economic growth in Central America: Evidence from a panel cointegration and error correction model

This study examines the relationship between energy consumption and economic growth for six Central American countries over the period 1980–2004 within a multivariate framework. Given the relatively short span of the time series data, a panel cointegration and error correction model is employed to infer the causal relationship. Based on the heterogeneous panel cointegration test by Pedroni (Pedroni, P., 1999. Critical values for cointegration tests in heterogeneous panels with multiple regressors. Oxford Bulletin of Economics and Statistics 61, 653–670; Pedroni, P., 2004. Panel cointegration: asymptotic and finite sample properties of pooled time series tests with an application to the PPP hypothesis: new results. Econometric Theory 20, 597–627), cointegration is present between real GDP, energy consumption, the labor force, and real gross fixed capital formation with the respective coefficients positive and statistically significant. The Granger-causality results indicate the presence of both short-run and long-run causality from energy consumption to economic growth which supports the growth hypothesis.     

Visible-near infrared spectroscopy sensor for predicting curd and whey composition during cheese processing

The potential of visible-near infrared spectra, obtained using a light backscatter sensor, in conjunction with chemometrics, to predict curd moisture and whey fat content in a cheese vat was examined. A three-factor (renneting temperature, calcium chloride, cutting time), central composite design was carried out in triplicate. Spectra (300–1,100 nm) of the product in the cheese vat were captured during syneresis using a prototype light backscatter sensor. Stirring followed upon cutting the gel, and samples of curd and whey were removed at 10 min intervals and analyzed for curd moisture and whey fat content. Spectral data were used to develop models for predicting curd moisture and whey fat contents using partial least squares regression. Subjecting the spectral data set to Jack-knifing improved the accuracy of the models. The whey fat models (R = 0.91, 0.95) and curd moisture model (R = 0.86, 0.89) provided good and approximate predictions, respectively. Visible-near infrared spectroscopy was found to have potential for the prediction of important syneresis indices in stirred cheese vats.     

Mathematical modeling of the full molecular weight distribution in ATRP techniques

In this work the molecular weight distribution (MWD) of several atom transfer radical polymerization (ATRP) techniques has been derived and solved using the Reduced Stiffness by Quasi Steady State Approximation (RSQSSA) methodology. The Quasi Steady State Approximation has been validated on the living radicals for normal, Simultaneous Reversible and Normal Initiation and Activators Regenerated by Electron Transfer (ARGET), and it is shown that the information lost due to its application is negligible. According to these results, RSQSSA shows the best performance in terms of wall‐clock time and required memory in comparison to implicit techniques and Predici. In the case of the ARGET technique, the model predictions show good agreement with experimental data. Finally, an analysis on the impact of the slow and fast activation of the initiator on the MWD using ARGET has been carried out, indicating that the optimal initiator to control the MWD should exhibit activation‐deactivation rates very similar to those of the polymeric equilibrium. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2762–2777, 2016     

Selective froth flotation of PVC from PVC/PET mixtures for the plastics recycling industry

It was found that strongly alkaline solutions of sodium hydroxide are able to destroy the hydrophobicity of polyethylene terephthalate (PET) whereas the hydrophobicity of polyvinyl chloride (PVC) remains only slightly affected by these solutions. On this basis, a technology involving treatment of PET and PVC particles with alkaline solutions followed by froth flotation of PVC with nonionic surfactants has been developed and tested at a laboratory scale. In both steps of this technology, appropriate experimental conditions, such as concentration of reagents, temperature and residence time, have been optimized through a detailed examination of all these variables on the efficiency and selectivity of PVC separation from PVC/PET mixtures of varying composition. It is demonstrated that using this technology 95–100% recovery of PET and PVC can be achieved in separate products from a variety of PVC/PET mixtures.     

Reversible Electronic Patterning of a Dynamically Responsive Hydrogel Medium

A dynamically responsive hydrogel medium is prepared from two self-assembling components, a polysaccharide (chitosan) and a surfactant (sodium dodecyl sulfate; SDS). It is shown that this medium can be patterned using an electrode “pen” to reconfigure supramolecular structure: cathodic writing induces neutral chitosan chains to form a crystalline network, while anodic writing generates cationic chitosan chains that electrostatically crosslink with anionic SDS micelles. Both supramolecular structures are re-configurable and each is stabilized by structure-induced shifts in chitosan's pKa, thus electronically written patterns can be erased, new patterns can be written, and patterns can be written in three dimensions. Further, it is shown that NaCl-induced morphological transitions of the SDS micelles allow patterns to be reversibly concealed or revealed. To demonstrate the versatility of this medium for information storage, a quick response (QR) code is electronically written and it is shown that this code can be recognized by a standard cellphone app. This QR code can be concealed by making the medium opaque (i.e., by obscuring the pattern) or by making the pattern evanescent (i.e., by making pattern invisible). Overall, this work demonstrates that a dynamically responsive medium composed of simple, safe and sustainable components can be reversibly patterned with spatial and quantitative control using top-down electronic inputs.     

A dynamic panel study of economic development and the electricity consumption-growth nexus

This study examines the relationship between electricity consumption and economic growth for 88 countries categorized into four panels based on the World Bank income classification (high, upper middle, lower middle, and low income) within a multivariate panel framework over the period 1990–2006. The Larsson et al. (2001) panel cointegration test indicates there is a long-run equilibrium relationship between real GDP, coal consumption, real gross fixed capital formation, and the labor force for the high, upper middle, and lower middle income country panels. The results from the panel vector error correction models reveal (1) bidirectional causality between electricity consumption and economic growth in both the short- and long-run for the high income and upper-middle income country panels; (2) unidirectional causality from electricity consumption to economic growth in the short-run, but bidirectional causality in the long-run for the lower-middle income country panel; and (3) unidirectional causality from electricity consumption to economic growth for the low income country panel.     

A dileucine-like sorting signal directs transport into an AP-3-dependent, clathrin-independent pathway to the yeast vacuole

Transport of yeast alkaline phosphatase (ALP) to the vacuole depends on the clathrin adaptor-like complex AP-3, but does not depend on proteins necessary for transport through pre-vacuolar endosomes. We have identified ALP sequences that direct sorting into the AP-3-dependent pathway using chimeric proteins containing residues from the ALP cytoplasmic domain fused to sequences from a Golgi-localized membrane protein, guanosine diphosphatase (GDPase). The full-length ALP cytoplasmic domain, or ALP amino acids 1-16 separated from the transmembrane domain by a spacer, directed GDPase chimeric proteins from the Golgi complex to the vacuole via the AP-3 pathway. Mutation of residues Leu13 and Val14 within the ALP cytoplasmic domain prevented AP-3-dependent vacuolar transport of both chimeric proteins and full-length ALP. This Leucine-Valine (LV)-based sorting signal targeted chimeric proteins and native ALP to the vacuole in cells lacking clathrin function. These results identify an LV-based sorting signal in the ALP cytoplasmic domain that directs transport into a clathrin-independent, AP-3-dependent pathway to the vacuole. The similarity of the ALP sorting signal to mammalian dileucine sorting motifs, and the evolutionary conservation of AP-3 subunits, suggests that dileucine-like signals constitute a core element for AP-3-dependent transport to lysosomal compartments in all eukaryotic cells.     

In‐Film Bioprocessing and Immunoanalysis with Electroaddressable Stimuli‐Responsive Polysaccharides

Advances in thin‐film fabrication are integral to enhancing the power of microelectronics while fabrication methods that allow the integration of biological molecules are enabling advances in bioelectronics. A thin‐film‐fabrication method that further extends the integration of biology with microelectronics by allowing living biological systems to be assembled, cultured, and analyzed on‐chip with the aid of localized electrical signals is described. Specifically, the blending of two stimuli‐responsive film‐forming polysaccharides for electroaddressing is reported. The first, alginate, can electrodeposit by undergoing a localized sol–gel transition in response to electrode‐imposed anodic signals. The second, agarose, can be co‐deposited with alginate and forms a gel upon a temperature reduction. Electrodeposition of this dual polysaccharide network is observed to be a simple, rapid, and spatially selective means for assembly. The bioprocessing capabilities are examined by co‐depositing a yeast clone engineered to display a variable lymphocyte receptor protein on the cell surface. Results demonstrate the in‐film expansion and induction of this cell population. Analysis of the cells' surface proteins is achieved by the electrophoretic delivery of immunoreagents into the film. These results demonstrate a simple and benign means to electroaddress hydrogel films for in‐film bioprocessing and immunoanalysis.     

Chronicity of Psychological Strain in Occupational Settings and the Accuracy of the General Health Questionnaire.

This article examines the proposition that the traditional scoring method of the General Health Questionnaire (GHQ) underestimates the number of respondents classified as "cases." A revised "chronic" scoring method (the CGHQ) is used and demonstrates superior construct validity and greater sensitivity. A comparison of the CGHQ and GHQ also shows the CGHQ to be a superior criterion measure. These claims are demonstrated by survey data gathered from 3 occupational samples (Ns = 11,637, 2,253, and 2,124). Results show that the CGHQ is more appropriate as a screening instrument for psychological morbidity. Tests of construct validity also favor the CGHQ with only a slight advantage for predictive validity in terms of variance explained. The more desirable statistical properties of the CGHQ result in a reduction of significant interaction terms and are strongly recommended in future studies as a means of controlling Type I errors when tests of moderation are examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)