OFF-FARM LABOR AND THE STRUCTURE OF U.S. AGRICULTURE: THE CASE OF CORN/SOYBEAN FARMS

While the growing importance of off-farm earnings suggests large benefits accrue to farmers from efforts to expand off-farm income opportunities, survival still depends on greater efficiency. To comprehensively gauge the economic health of farm operator households we interpret off-farm income as an output along with corn, soybeans, livestock, and other crops. To accomplish this task we use two related methodologies. First, using 2000 data, we setup a multiactivity cost function to analyze labor allocation decisions within the farm operator household and also to estimate returns to scale and scope. Second, using 1996-2000 data, we follow an input distance function approach to estimate returns to scale, technical progress, cost economies, and technical efficiency--and compare the relative performance of farm operator households with and without off-farm wages and salaries. Our preliminary results suggest that over our sample period, scale economies are a primary factor driving up farm operator household size and decreasing the competitiveness of small farm operator households in the base farm operator household model where off-farm income is constrained to zero. But small farm operator households appear to achieve efficiency levels more comparable to larger farm operator households when off-farm income is accommodated. The evidence therefore suggests that while short-falls in these productivity components are decreasing the competitiveness of small farm operator households as agricultural structure changes, corn/soybean farm operator households have partially adapted to such pressures by increasing off-farm income and, therefore, achieving economies of scope.Labor and Human Capital,

Human Exploration Spacecraft Testbed for Integration and Advancement (HESTIA)

The proposed paper will cover ongoing effort named HESTIA (Human Exploration Spacecraft Testbed for Integration and Advancement), led at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) to promote a cross-subsystem approach to developing Mars-enabling technologies with the ultimate goal of integrated system optimization. HESTIA also aims to develop the infrastructure required to rapidly test these highly integrated systems at a low cost. The initial focus is on the common fluids architecture required to enable human exploration of mars, specifically between life support and in-situ resource utilization (ISRU) subsystems. An overview of the advancements in both integrated technologies, in infrastructure, in simulation, and in modeling capabilities will be presented, as well as the results and findings of integrated testing,. Due to the enormous mass gear-ratio required for human exploration beyond low-earth orbit, (for every 1 kg of payload landed on Mars, 226 kg will be required on Earth), minimization of surface hardware and commodities is paramount. Hardware requirements can be minimized by reduction of equipment performing similar functions though for different subsystems. If hardware could be developed which meets the requirements of both life support and ISRU it could result in the reduction of primary hardware and/or reduction in spares. Minimization of commodities to the surface of mars can be achieved through the creation of higher efficiency systems producing little to no undesired waste, such as a closed-loop life support subsystem. Where complete efficiency is impossible or impractical, makeup commodities could be manufactured via ISRU. Although, utilization of ISRU products (oxygen and water) for crew consumption holds great promise of reducing demands on life support hardware, there exist concerns as to the purity and transportation of commodities. To date, ISRU has been focused on production rates and purities for propulsion needs. The meshing of requirements between all potential users, producers, and cleaners of oxygen and water is crucial to guiding the development of technologies which will be used to perform these functions. Various new capabilities are being developed as part of HESTIA, which will enable the integrated testing of these technologies. This includes the upgrading of a 20' diameter habitat chamber to eventually support long duration (90+ day) human-in-the-loop testing of advanced life support systems. Additionally, a 20' diameter vacuum chamber is being modified to create Mars atmospheric pressures and compositions. This chamber, designated the Mars Environment Chamber (MEC), will eventually be upgraded to include a dusty environment and thermal shroud to simulate conditions on the surface of Mars. In view that individual technologies will be in geographically diverse locations across NASA facilities and elsewhere in the world, schedule and funding constraints will likely limit the frequency of physical integration. When this is the case, absent subsystems can be either digitally or physically simulated. Using the Integrated Power Avionics and Software (iPAS) environment, HESTIA is able to bring together data from various subsystems in simulated surroundings, insert faults, errors, time delays, etc., and feed data into computer models or physical systems capable of reproducing the output of the absent subsystems for the consumption of a local subsystems. Although imperfect, this capability provides opportunities to test subsystem integration and interactions at a fraction of the cost. When a subsystem technology is too immature for integrated testing, models can be produced using the General-Use Nodal Network Solver (GUNNS) capability to simulate the overall system performance. In doing so, even technologies not yet on the drawing board can be integrated and overall system performance estimated. Through the integrated development of technologies, as well as of the infrastructure to rapidly and at a low cost, model, simulate, and test subsystem technologies early in their development, HESTIA is pioneering a new way of developing the future of human space exploration

FACTORS AFFECTING SOFTWARE MAINTENANCE PRODUCTIVITY: AN EXPLORATORY STUDYl

Systems developers and researchers have long been interested in the factors that affect software development productivity. Identification of factors as either aiding or hindering productivity enables management to take steps to encourage the positive influences and to eliminate the negative ones. This research has explored the possibility of developing an estimable model of software development productivity using a frontier estimation method. The approach taken is based upon output metrics for the entire project life-cycle, and includes project quality metrics. A large number of factors potentially affecting software maintenance productivity were included in this initial investigation. The empirical analysis of a pilot data set indicated that high project quality did not necessarily reduce project productivity. Significant factors in explaining positive variations in productivity included project team capability and good system response (turnaround) time. Factors significantly associated with negative variations in productivity included lack of team application experience and high project staff loading, The use of a new structured analysis and design methodology also resulted in lower short term productivity. These preliminary results have suggested a number of new research directions and have prompted the data-site to begin a full scale data collection effort in order to validate a model of software maintenance productivity

Productivity Growth, Technological Progress, and Technical Efficiency in the Heartland and Southern Cotton States:1996-1999.

Given recent concerns expressed about the structural transformation of agriculture and the health of the family farm this study provides a measure of the economic health of small and large farms at the state level. We use nonparametric frontier methods to measure and explain changes in the efficiency, productivity, and technological change of U.S. farms, employing USDAs annual 1996 to 1999 surveys of farms. Our results for the corn and cotton states analyzed identify particularly weak economic performance of small farms in Iowa, Louisiana, Oklahoma, and Wisconsin and of large farms in Missouri, Oklahoma, and South Carolina. Our results also indicate strong performance of small farms in several states. Thus, these results give policy makers a more detailed and up to date view of the overall economic health of the agricultural sector in the states analyzed than has previously been possible with aggregate state level analyses.Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,

Investigation into Cryogenic Tank Insulation Systems for the Mars Surface Environment

In order to use oxygen that is produced on the surface of Mars from In-Situ production processes in a chemical propulsion system, the oxygen must first be converted from vapor phase to liquid phase and then stored within the propellant tanks of the propulsion system. The oxygen must then be stored in the liquid phase for several years between when the liquefaction operations are initiated and when the ascent stage lifts off the Martian surface. Since the Space Exploration Initiative, NASA has been investing small sums of money into soft vacuum systems for Mars Applications. A study was done into these various insulation systems for soft vacuum insulation, to determine what types of systems might be best to further pursue. Five different architectures or cycles were considered: Aerogel-based multilayer Insulation (MLAI), Space Evacuated Mars Vacuum Jacket (SEMOV) (also known as lightweight vacuum jacket), Load Responsive-Multilayer Insulation, Spray on Foam with MLI, and MLAI in SEMOV. Models of each architecture were developed to give insight into the performance and losses of each of the options. The results were then compared across six categories: Insulation System Mass, Active System Power (both input and heat rejection), Insulation System Cost, Manufacturability, Reliability, and Operational Flexibility. The result was that a trade between reliability and mass was clearly identified. Systems with high mass, also had high perceived reliability; whereas, systems with lower mass and power had a much lower perceived reliability. In the end, the numerical trades of these systems showed nominally identical rankings. As a result it is recommended that NASA focus its Martian insulation development activities on demonstrating and improving the reliability of the lightweight identified systems

Poboljšanje fizičko-mehaničkih svojstava karbamazepina prekristalizacijom pri različitim pH

The morphology of crystals has an appreciable impact on the physicochemical properties of drugs. Drug properties such as flowability, dissolution, hardness and bioavailability may be affected by crystallinity behaviors of drugs. The objective of this study was to achieve improved physicomechanical properties of carbamazepine powder through recrystallization from aqueous solutions at different pH values. For this purpose, carbamazapine was recrystallized from aqueous solutions at different pH values (1, 7, 11). The morphology of crystals was investigated using scanning electron microscopy; X-ray powder diffraction (XRPD) was used to identify polymorphism; thermodynamic properties were analyzed using differential scanning calorimetery (DSC). Dissolution was determined using USP dissolution apparatus. Mechanical behavior of recrystallized carbamazepine powders was investigated by making tablets under different compaction pressures and measuring their hardness. SEM studies showed that carbamazepine crystallization in different media affected the morphology and size of carbamazepine crystals. The shape of carbamazepine crystals changed from flaky or thin plate-like to needle-shaped. XRPD and DSC results ruled out any crystallinity changes occurring due to the temperature or pH of crystallization media. The crushing strength of tablets indicated that all the recrystallized carbamazepine samples had better compactibility than the original carbamazepine powder. In vitro dissolution studies of carbamazepine samples showed a higher dissolution rate of carbamazepine crystals obtained from media with pH 11 and 1. Carbamazepine particles recrystallized from aqueous solutions of different pH values (all media) appeared to have superior mechanical properties to those of the original carbamazepine sample.Morfologija kristala ima značajan utjecaj na fizičko-mehanička svojstva lijekova. Kristaliničnost može utjecati na tečnost, oslobađanje, tvrdoću i bioraspoloživost lijekova. Cilj ovog rada bio je poboljšati fizičko-mehanička svojstva praha karbamazepina prekristalizacijom iz vodenih otopina pri različitim pH vrijednostima (1, 7 i 11). Fizičko-mehanička svojstva prekristaliziranog karbamazepina određivana su na sljedeći način: morfologija kristala ispitivana je pretražnom elektronskom mikroskopijom, polimorfi su identificirani rendgenskom difrakcijom praha (XRPD), a termodinamička svojstva analizirana su diferencijalnom pretražnom kalorimetrijom (DSC). Topljivost je određena pomoću aparata prema USP. Mehanička svojstva prekristaliziranog karbamazepina ispitivana su tijekom tabletiranja pri različitim tlakovima i mjerenjem tvrdoće nastalih tableta. SEM ispitivanja pokazala su da kristalizacija karbamazepina iz različitih medija utječe na morfologiju i veličinu kristala. Oblik kristala mijenjao se od pahuljastog ili pločastog do igličastog. Rezultati dobiveni XRPD i DSC metodama isključili su promjene kristaliničnosti zbog temperature ili pH medija. Mjerenjem lomljivosti tableta utvrđeno je da su svi prekristalizirani uzorci karbamazepina bili kompaktniji od polaznog praškastog uzorka. Ispitivanja topljivosti in vitro pokazala su da su kristali dobiveni iz otopine s pH 11 i 1 topljiviji. Uzorci karbamazepina dobiveni prekristalizacijom iz vodenih otopina različite pH vrijednosti imali su bolja mehanička svojstva od originalnog uzorka karbamazepina

Inhibition of fast axonal transport by pathogenic SOD1 involves activation of p38 MAP kinase

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e65235, doi:10.1371/journal.pone.0065235.Dying-back degeneration of motor neuron axons represents an established feature of familial amyotrophic lateral sclerosis (FALS) associated with superoxide dismutase 1 (SOD1) mutations, but axon-autonomous effects of pathogenic SOD1 remained undefined. Characteristics of motor neurons affected in FALS include abnormal kinase activation, aberrant neurofilament phosphorylation, and fast axonal transport (FAT) deficits, but functional relationships among these pathogenic events were unclear. Experiments in isolated squid axoplasm reveal that FALS-related SOD1 mutant polypeptides inhibit FAT through a mechanism involving a p38 mitogen activated protein kinase pathway. Mutant SOD1 activated neuronal p38 in mouse spinal cord, neuroblastoma cells and squid axoplasm. Active p38 MAP kinase phosphorylated kinesin-1, and this phosphorylation event inhibited kinesin-1. Finally, vesicle motility assays revealed previously unrecognized, isoform-specific effects of p38 on FAT. Axon-autonomous activation of the p38 pathway represents a novel gain of toxic function for FALS-linked SOD1 proteins consistent with the dying-back pattern of neurodegeneration characteristic of ALS.Support was provided by 2007/2008 Marine Biological Laboratory summer fellowships and NIH (NS066942A) grants to GM; Howard Hughes Medical Institute-USE Grant #52006287 to Hunter College of CUNY (LM); Muscular Dystrophy Association (MDA) and NIH (R01NS44170) grants to LJH; MDA and NIH (NS23868, NS23320, NS41170) grants to STB; NIH grant MH066179 to GB; NIH grants R01AG031311 and R01NS055951 to DMW; NIH (U01NS05225, R01NS050557, 1RC1NS068391, 1RC2NS070342) grants to RHB; R01NS067206 to DAB; ALS Association grants to GM, AT, RHB, and STB; and ALS/CVS Therapy Alliance grants to RHB, GM, AT, LJH, and DAB. RHB and AT received support from the Angel Fund. RHB also received support from the DeBourgknecht Fund for ALS Research, P2ALS and Project ALS

OTIMIZAÇÃO DE PORTFÓLIOS: ANÁLISE DE EFICIÊNCIA

This article aims to analyze the behavior of a portfolio of assets selected by Data Envelopment Analysis (DEA), optimized by the Sharpe approach, and compare it to portfolios of assets obtained only by DEA or the Sharpe approach. To do that, we used the DEA model to assess the efficiency of shares of the São Paulo Stock Exchange (Bovespa), employing return, variance and other indicators such as input and output variables. Also, we used the Sharpe approach to optimize the portfolio composition. In the comparison of portfolios, we noted that the resulting combination of both models performed better than the portfolios optimized by only one of the models