79 research outputs found
Performance of Year-Round Cropping Systems on Three Tropical Soil Families
A favorable climate throughout the year as well as the prevailing socio-economic conditions in the tropics are ideal for multiple cropping in time and space. Despite of its relevance, year-round cropping systems have seldom been used to evaluate the productivity of well-characterized tropical agroenvironments. The major objectives of this study were to monitor the effects of agroclimatic parameters on the performance of various crops and sequences of crops, and to investigate the possibility of stratifying crop production potential, on the basis of the soil family category of Soil Taxonomy, in the tropics.
Year-round cropping patterns were tested on a weather-monitored network of ten sites located in Indonesia, The Philippines and Hawaii representing the tropical soil families of thixotropic, isothermic Hydric Dystrandepts; clayey, kaolinitic, isohyperthermic Tropeptic Eutrustox and clayey, kaolinitic, isohyperthermic Typic Paleudults. The cropping patterns used were specifically designed for each of the three agroenvironments and similar management practices were followed on all sites.
The sequential cropping pattern of Irish potato followed by soybean and then by field corn, designed specifically for the Tropeptic Eutrustox agroenvironment, gave the highest calorie and protein yield (46581 k cal/ha and 2101 kg/ha, respectively) at the Eutrustox site of Waipio, Hawaii. The above cropping pattern also resulted in higher calorie and protein production at the Dystrandept site in Kukaiau, Hawaii compared to the specifically-designed pattern of Irish potato and vegetables followed by vegetables and then followed by soybean and peanut. The Dystrandept sites in Indonesia and The Philippines had lower yield potential compared to the site of Kukaiau, mainly because of higher temperatures of the former that resulted in low yields of vegetables and Irish potato.
Head cabbage, mustard cabbage, Irish potato, carrot and bushbean were found to be susceptible to high temperature and excess moisture. The yields of the above crops were highly correlated (r = -0.70**) with soil temperature at 10 cm, and their best yields were obtained within a soil temperature range of 18 to 23°C. In contrast, soybean and peanut were adapted to a wide range (21 - 28°C) of air temperature and soil moisture. Soybean planted during April-May (long days) gave significantly higher yields compared to August-September (short days) plantings. Multiple regression equations with agroclimatic parameters as independent variables, were derived to predict yields of crops. Except for green corn, only crops that were sensitive to temperature and excess moisture (mustard cabbage, head cabbage, carrot, bushbean and Irish potato) had prediction equations with coefficients of determination close to 0.80. However, for soybean and peanut the best models incorporating as many as six environmental parameters explained less than 50 percent of the yield variability.
In the Hydric Dystrandepts and Typic Paleudults (udic moisture regime), most crops grown year-round did well without irrigation. Crop performance in Tropeptic Eutrustox confirmed the absolute necessity of supplemental irrigation for year-round crop production under an ustic moisture regime.
Response to Rhizobium inoculation as reflected by soybean yields, was variable. However, the number of significant responses to inoculation was greater in the Tropeptic Eutrustox than in Hydric Dystrandept sites. Bushbean yields were significantly higher in the "bushbean + mustard cabbage" intercrop combination then in the "bushbean + green corn" combination. Air tenperature was negatively correlated (r = -0.96**) with the number of days required for maturity of Irish potato.
In this study, segregation of a soil family based on crop performance was possible only in case of lypic Paleudults. High average air and soil temperatures (> 26°C) prevalent in the Paleudults resulted in poor performance of temperature-sensitive crops such as head cabbage, mustard cabbage, Irish potato and carrot
Babesia microti, Upstate New York
Five cases of human babesiosis were reported in the Lower Hudson Valley Region of New York State in 2001. An investigation to determine if Babesia microti was present in local Ixodes scapularis ticks yielded 5 positive pools in 123 pools tested, the first detection of B. microti from field-collected I. scapularis in upstate New York
Role of Prognostics in Support of Integrated Risk-based Engineering in Nuclear Power Plant Safety
There is a growing trend in applying a prognostics and health management approach to engineering systems in general and space and aviation systems in particular. This paper reviews the role of prognostics and health management approach in support of integrated risk-based applications to nuclear power plants, like risk-based inservice inspection, technical specification optimization, maintenance optimization, etc. The review involves a survey of the state-of-art technologies in prognostics and health management and an exploration of its role in support of integrated risk-based engineering and how the technology can be adopted to realize enhanced safety and operational performance. An integrated risk-based engineering framework for nuclear power plants has been proposed, where probabilistic risk assessment plays the role of identification, prioritization and optimization of systems, structures, and components, while deterministic assessment is performed using a prognostics and health management approach. Keeping in view the requirements of structural reliability assessment, the paper also proposes essential features of a ‘Mechanics-of-Failure ’ approach in support of integrated risk-based engineering. The performance criteria used in prognostics and health management has been adopted to meet requirements of risk-based applications. 1
Modelling of resource allocation to health care authorities in Stockholm County
Since the Stockholm County Council introduced a system of purchasers and providers there has been a quest for population-based resource allocation models to allocate monies to purchasers of health care. In contrast to models used in Britain, Swedish models have been based on individual level data. This paper presents recent developments in the model used in Stockholm for all care except primary care, testing new statistical methods for compression and clustering of the matrices used and the effect of introducing diagnostic information in addition to the demographic and socio-economic information used before. We also show the effect of using more current data sources by replacing existing census variables with data from annually updated registers. Since the aim is to use the resource allocation models for prospective budgeting we test and evaluate the predictive power of the models one to two years ahead. Moreover, two calibration methods are compared: Cross-sectional modelling, based on data for one year only, versus prospective modelling, using population characteristics for one year and registered health-care costs for a following year. While models including diagnostic information are deemed valuable, the prospective models yield little improvement. Further, although it takes a combination of new variables to replace the census based model, the resulting model now implemented by Stockholm County Council has fewer estimated parameters. Copyright Kluwer Academic Publishers 2000
Prognostics & Health Management of Swing Type Check Valves
Abstract — Prognostics and Health Management is emerging as new paradigm to address issues related to enhancing the safety as well as availability. The enabling technologies are state-of-the art in on-line monitoring or periodic surveillance tools and availability of degradation assessment approaches that provide a framework for residual life assessment of component. Availability of physics of failure or mechanics of failure models and intelligent tools are vital for implementation of a prognostics and health management programme. This paper presents an approach for prognostics and health management of Check valves. The results shows that this approach is promising to detect in advance the incipient failure such that maintenance programme can be initiated to improve the availability as well as safety. Even though this approach addresses modelling of swing type of check valves, the models can easily be adopted for other type of check valves als
Region specific detection of neuroblastoma loss of heterozygosity at multiple loci simultaneously using a SNP-based tag-array platform.
Many cancers are characterized by chromosomal aberrations that may be predictive of disease outcome. Human
neuroblastomas are characterized by somatically acquired copy number changes, including loss of heterozygosity
(LOH) at multiple chromosomal loci, and these aberrations are strongly associated with clinical phenotype including
patient outcome. We developed a method to assess region-specific LOH by genotyping multiple SNPs simultaneously
in DNA from tumor tissues. We identified informative SNPs at an average 293-kb density across nine regions of
recurrent LOH in human neuroblastomas. We also identified SNPs in two copy number neutral regions, as well as
two regions of copy number gain. SNPs were PCR-amplified in 12-plex reactions and used in solution-phase
single-nucleotide extension incorporating tagged dideoxynucleotides. Each extension primer had 5 complementarity
to one of 2000 oligonucleotides on a commercially available tag-array platform allowing for solid-phase sorting and
identification of individual SNPs. This approach allowed for simultaneous detection of multiple regions of LOH in six
human neuroblastoma-derived cell lines, and, more importantly, 14 human neuroblastoma primary tumors.
Concordance with conventional genotyping was nearly absolute. Detection of LOH in this assay may not require
comparison to matched normal DNAs because of the redundancy of informative SNPs in each region. The
customized tag-array system for LOH detection described here is rapid, results in parallel assessment of multiple
genomic alterations, and may speed identification of and/or assaying prognostically relevant DNA copy number
alterations in many human cancers
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