2,706 research outputs found
Agricultural Household-Firm Units: Adjustments to Change
This paper assesses agricultural household-firm unit models to determine a useful typology for agricultural policy assessment that draws upon their use. Both standard and bargaining models for analyzing household decisions, including production, consumption, labor, credit, fertility and child schooling, intergenerational transfer, among other key behaviors of households are discussed, as well as data and estimation issues often encountered with household models. Relevant dimensions of a country or region typology are then suggested, focusing on (1) the extent to which markets, particularly labor markets, are perfect, missing or mixed; (2) relevant intra-household and key demographic considerations; and (3) the differentiation of particular household-firm units that are particularly disadvantaged and may be of the most critical policy concern.agricultural households, farm households, labor, labor adjustments, off-farm employment, Consumer/Household Economics, Labor and Human Capital,
STRESS AMONG FARM WOMEN:AN ANALYSIS OF FARM HOUSEHOLDS IN PENNSYLVANIA
Farming is among the high-stress occupations in the United States and farm women have higher stress scores due to multiple job holdings. The study investigates the determinants of time stress experienced by farm women in Pennsylvania applying an economic model of stress developed by Hamermesh and Lee (2003).Farm Management,
Influence of loading rate, alkali fibre treatment and crystallinity on fracture toughness of random short hemp fibre reinforced polylactide bio-composites
Plane-strain fracture toughness (KIc) of random short hemp fibre reinforced polylactide (PLA) bio-composites was investigated along with the effect of loading rate, fibre treatment and PLA crystallinity. Fracture toughness testing was carried out at loading rates varying from 0.5 to 20 mm/min using single-edge-notched bending specimens with 0 to 30 wt% fibre. KQ (trial KIc) of composites decreased as loading rate increased, until stabilising to give KIc values at a loading rate of 10 mm/min and higher. The reduction of crazing and stress whitening, as well as a more direct crack path observed in PLA samples combined with reduced plastic deformation observed in composites provided explanation for this reduction. KIc of composites was found to decrease with increased fibre content and fibre treatment with sodium hydroxide. Studies controlling the degree of PLA crystallinity by heat treatment or “annealing” showed that reduction of KIc can be attributed to increased crystallinity
Synthetic (p)ppGpp analogue is an inhibitor of stringent response in mycobacteria
Bacteria elicit an adaptive response against hostile conditions such as starvation and other kinds of stresses. Their ability to survive such conditions depends, in part, on stringent response pathways. (p)ppGpp, considered to be the master regulator of the stringent response, is a novel target for inhibiting the survival of bacteria. In mycobacteria, the (p)ppGpp synthetase activity of bifunctional Rel is critical for stress response and persistence inside a host. Our aim was to design an inhibitor of (p)ppGpp synthesis, monitor its efficiency using enzyme kinetics, and assess its phenotypic effects in mycobacteria. As such, new sets of inhibitors targeting (p)ppGpp synthesis were synthesized and characterized by mass spectrometry and nuclear magnetic resonance spectroscopy. We observed significant inhibition of (p)ppGpp synthesis by Rel(Msm) in the presence of designed inhibitors in a dose-dependent manner, which we further confirmed by monitoring the enzyme kinetics. The Rel enzyme inhibitor binding kinetics were investigated by isothermal titration calorimetry. Subsequently, the effects of the compounds on long-term persistence, biofilm formation, and biofilm disruption were assayed in Mycobacterium smegmatis, where inhibition in each case was observed. In vivo, (p)ppGpp levels were found to be downregulated in M. smegmatis treated with the synthetic inhibitors. The compounds reported here also inhibited biofilm formation by the pathogen Mycobacterium tuberculosis. The compounds were tested for toxicity by using an MTT assay with H460 cells and a hemolysis assay with human red blood cells, for which they were found to be nontoxic. The permeability of compounds across the cell membrane of human lung epithelial cells was also confirmed by mass spectrometry
ShapeCodes: Self-Supervised Feature Learning by Lifting Views to Viewgrids
We introduce an unsupervised feature learning approach that embeds 3D shape
information into a single-view image representation. The main idea is a
self-supervised training objective that, given only a single 2D image, requires
all unseen views of the object to be predictable from learned features. We
implement this idea as an encoder-decoder convolutional neural network. The
network maps an input image of an unknown category and unknown viewpoint to a
latent space, from which a deconvolutional decoder can best "lift" the image to
its complete viewgrid showing the object from all viewing angles. Our
class-agnostic training procedure encourages the representation to capture
fundamental shape primitives and semantic regularities in a data-driven
manner---without manual semantic labels. Our results on two widely-used shape
datasets show 1) our approach successfully learns to perform "mental rotation"
even for objects unseen during training, and 2) the learned latent space is a
powerful representation for object recognition, outperforming several existing
unsupervised feature learning methods.Comment: To appear at ECCV 201
Detection of Sugar-Lectin Interactions by Multivalent Dendritic Sugar Functionalized Single-Walled Carbon Nanotubes
We show that single walled carbon nanotubes (SWNT) decorated with sugar
functionalized poly (propyl ether imine) (PETIM) dendrimer is a very sensitive
platform to quantitatively detect carbohydrate recognizing proteins, namely,
lectins. The changes in electrical conductivity of SWNT in field effect
transistor device due to carbohydrate - protein interactions form the basis of
present study. The mannose sugar attached PETIM dendrimers undergo charge -
transfer interactions with the SWNT. The changes in the conductance of the
dendritic sugar functionalized SWNT after addition of lectins in varying
concentrations were found to follow the Langmuir type isotherm, giving the
concanavalin A (Con A) - mannose affinity constant to be 8.5 x 106 M-1. The
increase in the device conductance observed after adding 10 nM of Con A is same
as after adding 20 \muM of a non - specific lectin peanut agglutinin, showing
the high specificity of the Con A - mannose interactions. The specificity of
sugar-lectin interactions was characterized further by observing significant
shifts in Raman modes of the SWNT.Comment: 12 pages, 3 figure
A SURVEY TO DESIGN AND DEVELOP AUTOMATIC IRRIGATION SYSTEM
Abstract: Agriculture is the backbone of a nation for its economic growth and to attain self sustain nation. Due to global warming and industrialization farmers are struggling to irrigate the crops and in water management. To reduce the burden of farmers, modern technologies based on Microcontrollers, wireless communicating devices like GSM, Zigbee, Bluetooth etc. and special application software's were developed and introduced to automate the irrigation system for better water usage. In this work, a survey related to the automating irrigation system is discussed and different microcontrollers are compared. This survey deals with real time issues in irrigation and future research scope for irrigation automation.Keywords: Agriculture, Irrigation, Microcontroller, WS
PDDG/PM3 and PDDG/MNDO: improved semiempirical methods
Two new semiempirical methods employing a Pairwise Distance Directed Gaussian modification have been developed: PDDG/PM3 and PDDG/MNDO; they are easily implemented in existing software, and yield heats of formation for compounds containing C, H, N, and O atoms with significantly improved accuracy over the standard NDDO schemes, PM5, PM3, AM1, and MNDO. The PDDG/PM3 results for heats of formation also show substantial improvement over density functional theory with large basis sets. The PDDG modifications consist of a single function, which is added to the existing pairwise core repulsion functions within PM3 and MNDO, a reparameterized semiempirical parameter set, and modified computation of the energy of formation of a gaseous atom. The PDDG addition introduces functional group information via pairwise atomic interactions using only atom-based parameters. For 622 diverse molecules containing C, H, N, and O atoms, mean absolute errors in calculated heats of formation are reduced from 4.4 to 3.2 kcal/mol and from 8.4 to 5.2 kcal/mol using the PDDG modified versions of PM3 and MNDO over the standard versions, respectively. Several specific problems are overcome, including the relative stability of hydrocarbon isomers, and energetics of small rings and molecules containing multiple heteroatoms. The internal consistency of PDDG energies is also significantly improved, enabling more reliable analysis of isomerization energies and trends across series of molecules; PDDG isomerization energies show significant improvement over B3LYP/6-31G∗ results. Comparison of heats of formation, ionization potentials, dipole moments, isomer, and conformer energetics, intermolecular interaction energies, activation energies, and molecular geometries from the PDDG techniques is made to experimental data and values from other semiempirical and ab initio methods
Origin and evolution of the zodiacal dust cloud
The astrophysical importance of the zodiacal cloud became more apparent. The most useful source of information on the structure of the zodiacal cloud is the Infrared Astronomical Satellite (IRAS) observations. A substantial fraction of the extensive IRAS data set was analyzed. Also, a numerical model was developed (SIMUL) that allows to calculate the distribution of night-sky brightness that would be produced by any particular distribution of dust particle orbits. This model includes the effects of orbital perturbations by both the planets and solar radiation, it reproduces the exact viewing geometry of the IRAS telescope, and allows for the eccentricity of the Earth's orbit. SIMUL now is used to model not just the solar system dust bands discovered by IRAS but the whole zodiacal cloud
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