Spatial Autocorrelation Panel Regression: Agricultural Production and Transport Connectivity

Transport infrastructure is an important determinant of agricultural productivity. Using various new spatial data, the paper measures different types of transport accessibility and estimates their impacts in Ethiopia. The paper takes advantage of a historical event that Ethiopia, a landlocked country, ceased freight rail operations connecting its capital and the main seaport in the late 2000s. Using the substantial changes in transport accessibility, the spatial autocorrelation panel regression is applied to show that the proximity to close markets and the access to the port are of particular importance for agricultural production. The elasticity is estimated at about ?0.05 to ?0.13, depending on type of accessibility. It is also found that there are considerable spillover effects that come from the spatial autocorrelation errors, meaning that crop production at one place is affected by its neighborhood environment, possibly including land fertility and weather conditions.

     

The significance of air velocity and turbulence intensity for responses to horizontal drafts in a constant air temperature of 23°C

Aim: The aim was to prove the significance of air velocity and turbulence intensity on the responses to drafts and if air velocity is adequately weighted in the draft rating model (DR-model) proposed in ISO 7730 (1994). Methods: Seventeen healthy persons (9 women, 8 men, 19–51 yr) took part in 12 randomly arranged 1-h sessions where horizontal drafts were directed towards the dorsolateral body sites of the sedentary persons. Mean air velocity was varied in 4 (  m/s) and turbulence intensity in 3 steps (Tu: <30,≈50,>70%) but were kept constant during the single sessions, whereas air velocities were increased every 15 min in the basic experiments performed for the DR-model. Air temperature was 23°C, humidity varied between 40% and 60%. Subjective perception and annoyance due to drafts were registered every 5 min using a list of prescribed body parts and skin temperature was measured continuously throughout the sessions at the forearm and at the neck. Results: Draft-induced general annoyance (if draft-induced annoyance was stated for at least one body site) and draft-induced local annoyance as stated for the neck and for the forearm increased with air velocity and/or with turbulence intensity. The decrease in skin temperature, however, was only related to air velocity but not to turbulence intensity. Air velocities are obviously not accurately weighted in the draft-rating model (ISO 7730, 1994). As compared to the effects observed here, the effects predicted with the DR-model were smaller in case of mean air velocities of 0.3 m/s and less but greater for 0.4 m/s. Concerning rather sedentary persons it seems that drafts are tolerable as long as mean air velocities do not exceed 0.2 m/s and as long as turbulence intensity remains below 30% in air temperature of 23°C.

Relevance to industry

Drafts are the most annoying climatic factor at many workplaces and assumed to reduce satisfaction with work, to impair performance and perhaps even health (Griefahn et al., Ind. Health 38 (2000b) 30). The limitation of drafts is therefore an important contribution to industrial safety. Using the draft-rating model proposed in ISO 7730 (1994) for the evaluation and for the prediction of draft-induced annoyance, it must be considered that the model underestimates the effects of drafts in case of air velocities of 0.3 m/s which prevail at more than 85% of workplaces in offices and in the industry (Griefahn, 1999; Zhou, Ph.D. Thesis, International Center for Indoor Environment and Energy, Department of Energy Engineering, Technical University of Denmark, Lyngby, 1999).     

Dielectric and lattice-dynamical properties of III-nitrides

First-principles calculations are performed to investigate dynamical and dielectric properties of group-III-nitrides. We focus on vibrational frequencies, dynamical charges, and the phonon density of states of cubic AlN, GaN, and InN. Chemical trends are derived and discussed. The first ab initio calculations of phonon branches and density of states are presented for an ordered In_xGa_1−xN structure.     

The Conversion of UDP-Glc to UDP-Man: In Silico and Biochemical Exploration To Improve the Catalytic Efficiency of CDP-Tyvelose C2-Epimerases

A promiscuous CDP-tyvelose 2-epimerase (TyvE) from Thermodesulfatator atlanticus (TaTyvE) belonging to the nucleotide sugar active short-chain dehydrogenase/reductase superfamily (NS-SDRs) was recently discovered. TaTyvE performs the slow conversion of NDP-glucose (NDP-Glc) to NDP-mannose (NDP-Man). Here, we present the sequence fingerprints that are indicative of the conversion of UDP-Glc to UDP-Man in TyvE-like enzymes based on the heptagonal box motifs. Our data-mining approach led to the identification of 11 additional TyvE-like enzymes for the conversion of UDP-Glc to UDP-Man. We characterized the top two wild-type candidates, which show a 15- and 20-fold improved catalytic efficiency, respectively, on UDP-Glc compared to TaTyvE. In addition, we present a quadruple variant of one of the identified enzymes with a 70-fold improved catalytic efficiency on UDP-Glc compared to TaTyvE. These findings could help the design of new nucleotide production pathways starting from a cheap sugar substrate like glucose or sucrose.     

Antidepressant drugs appear to enhance cocaine-induced toxicity.

It has been shown that cocaine-induced convulsions and lethality appear to be mediated by serotonin and dopamine neurotransmission, respectively. However, many antidepressants considered for treatment of cocaine addiction target these monoamine systems and may thus amplify these toxic effects during relapse. In this study, the authors assessed whether pretreatment with antidepressants influences cocaine-induced toxicity in mice as well as the potency of these medications at cocaine-binding sites previously shown to be associated with cocaine toxicity. Overall, selective serotonin reuptake inhibitors (SSRIs) facilitated cocaine-induced convulsions but not lethality. Dopamine uptake inhibition facilitated cocaine-induced lethality, but not convulsion. The SSRI sertraline enhanced neither convulsions nor lethality and may be unique due to its high affinity for sigma receptors. These results have important implications for safe and effective addiction treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performing Changes in Product Development: A Framework with Keys for Industrial Application

Industrial product development requires continuous improvements in work procedures as a result of constantly changing demands. Support tools have proven to be an oft chosen way to meet new demands; however, few research efforts have been made in how to implement new tools. This article is a contribution to knowledge on carrying out the implementation of support tools. The basis consists of four field studies performed during 1994–1999, containing 78 qualitative research interviews and focusing on the implementation and use of different support tools. A re-analysis has been performed of selected interviews from the field studies, in total 30 interviews. This resulted in recommendations for an implementation framework, consisting of an Implementation Cycle, Organizational Change Field and Managerial Consistence, and five implementation keys: Goal setting, Kowledge Development, Anchoring at All Levels, Suitable Resources and Focus on the Individual.