269 research outputs found
FORECASTING CRITICAL AIRCRAFT LAUNCH AND RECOVERY EQUIPMENT (ALRE) COMPONENTS' DEMAND
Demand signals across the Navy’s NIMITZ Class Carrier (CVN) Aircraft Launch and Recovery Equipment (ALRE) market-basket are highly erratic and do not fit neatly into the traditional demand-based sparing construct. This causes the Naval Supply Systems Command Weapons Systems Support (NAVSUP WSS) planning efforts to continually lag behind requirements, with material often arriving late-to-need. This project attempts to develop a comprehensive and more reliable ALRE material requirement forecast model. To accomplish this effectively, a comprehensive list of historical CVN ALRE demand data were analyzed in order to identify any correlation between ALRE demand and a ship’s operating phase status, and to identify whether that correlation directly drives ALRE demand. The analysis begins by collecting historical CVN ALRE demand data and identifying the improvements for the current forecasting model. After a complete analysis of the current forecasting model, we utilized multiple linear regression and evaluated various forecasting methods as the best available methods for developing/discovering an optimized and robust forecasting method. In conclusion, the extremely low demand quantities of critical ALRE components continue to make forecasting extremely unreliable, but we believe NAVSUP can improve the accuracy of ALRE demand forecast by adapting a flexible forecasting system.NAVSUPhttp://archive.org/details/forecastingcriti1094561212Lieutenant Commander, United States NavyLieutenant, United States NavyLieutenant Commander, United States NavyApproved for public release; distribution is unlimited
Characterisation of Seasonal Rainfall for Cropping Schedules
El Nino-South Oscillation (ENSO) phenomenon occurs in the Equatorial Eastern Pacific Ocean and has been noted to account significantly for rainfall variability in many parts of the world, particularly tropical regions.This variability is very important in rainfed crop production and needs to be well understood. Thirty years of daily rainfall data (1976–2006 excluding 1991) from the Akatsi District in the Volta Region of Ghana were analysed to observe the variation of rainfall characteristics such as onset and cessation dates, seasonal rainfall amount and their temporal distribution with ENSO phase, namely El Nino, La Nina and Neutral. Using  rainfallreference evapotranspiration relationships, the onset of rainfall during La Nina and Neutral seasons occurred within the same period, March 11–20, but about a month late (April 11–20) during El Nino. Without regards to ENSO phase, the long-term mean onset date of the rainy season occurred from March 11–20. Annual and major season (March–July) rainfall amounts decreased in the order of these ENSO phases; La Nina, Neutral and El Nino but showed an opposite decreasing order of El Nino, Neutral and La Nina during the minor seasons (September-November). The trend of variability of rainfall distribution during the major season was observed to be highest during El Nino years and least during Neutral years. The study also showed that the optimum planting periods on 10-day time scales during La Nina, Neutral and El Nino years were found to be March 13–22; March, 17–26 and April 20–29, with March 16–25 for the long-term situation. These observations seem to reveal that long-term or climatological observations alone are no longer sufficient for seasonal rainfall prediction to aid cropping schedules
Scaling the saturated hydraulic conductivity of an Alfisol
Alfisols exhibit a high degree of spatial variability in their physical properties. As a result, it is difficult to use information on physical parameters measured at one location to model larger-scale hydrologic processes. In this study, the saturated hydraulic conductivity, Ks, of an Alfisol was determined on 109 undisturbed monoliths using the falling-head permeameter method. The model developed by Arya & Paris (Soil Science Society of America Journal 45, 1023-1030, 1981) was used to calculate the pore volume from sand and clay fractions. Scaling factors were calculated from the measured Ks, sand pore-volume, clay pore-volume, clay content and effective porosity, using the similar media concept. Prediction of Ks of gravelly Alfisol using clay pore-volume is confounded by high gravel content which, when discounted, improves the prediction remarkably. The scaled mean saturated hydraulic conductivity K* for all horizons of the alfisol was approximately 1.0 × 10-5 m s-
Smartphone colorimetry using ambient subtraction: Application to neonatal jaundice screening in Ghana
A smartphone app to screen for neonatal jaundice has a large
potential impact in reducing neonatal death and disability.
Our app, neoSCB, uses a colour measurement of the sclera
to make a screening decision. Although there are numerous
benefits of a smartphone-based approach, smartphone colour
measurement that is accurate and repeatable is a challenge.
Using data from a clinical setting in Ghana, we compare
sclera colour measurement using an ambient subtraction
method to sclera colour measurement using a standard colour
card method, and find they are comparable provided the subtracted signal-to-noise ratio (SSNR) is sufficient. Calculating
a screening decision metric via the colour card method gave
100% sensitivity and 69% specificity (n=87), while applying
the ambient subtraction method gave 100% sensitivity and
78% specificity (SSNR>3.5; n=50)
Tillage systems and soils in the semi-arid tropics
Even though conservation tillage may be ideal for the semi-arid tropics (SAT) in view of results from studies and tillage practices in the U.S.A. and Australia, studies conducted in semi-arid regions of Africa appear to support the use of conventional tillage systems. Some of the reasons for this apparent discrepancy are because of the physical properties of the soils in semi-arid Africa, particularly the Sahelian zones where the soils are sandy, have high bulk densities and therefore low total porosities and form crusts upon wetting and drying. Consequently, no-till or reduced tillage systems that do not have the soil surface covered by residue in irder to prevent formation of crust as a result of raindrop impact, tend to lose water through runoff in a region where water economy is essential. Also, because these soils have inherently high bulk densities, conventional tillage systems appear to be suitable since they increase the macropores, reduce both bulk density and strength and thus ensure prolific root distribution and the resultant exploration of water and nutrients at greater soil depths. Notwithstanding, it seems that since most of the SAT soils are structurally unstable, further conventional tillage even though it has ephemeral advantages, may in the long term be exacerbating the problems of structural instability and their deleterious effect on water and soil conservation and therefore on crop production. We suggest that at this stage soil tillage research in the semi-arid regions of Africa and Asia should re-examine some of the concepts of conservation tillage in relation to soil physical properties and processes in order to obtain a tillage system that ensures high crop yields without destruction of the soil resource
Feasibility of smartphone colorimetry of the face as an anaemia screening tool for infants and young children in Ghana
Background Anaemia affects approximately a quarter of the global population. When anaemia occurs during childhood, it can increase susceptibility to infectious diseases and impair cognitive development. This research uses smartphone-based colorimetry to develop a non-invasive technique for screening for anaemia in a previously understudied population of infants and young children in Ghana. Methods We propose a colorimetric algorithm for screening for anaemia which uses a novel combination of three regions of interest: the lower eyelid (palpebral conjunctiva), the sclera, and the mucosal membrane adjacent to the lower lip. These regions are chosen to have minimal skin pigmentation occluding the blood chromaticity. As part of the algorithm development, different methods were compared for (1) accounting for varying ambient lighting, and (2) choosing a chromaticity metric for each region of interest. In comparison to some prior work, no specialist hardware (such as a colour reference card) is required for image acquisition. Results Sixty-two patients under 4 years of age were recruited as a convenience clinical sample in Korle Bu Teaching Hospital, Ghana. Forty-three of these had quality images for all regions of interest. Using a naïve Bayes classifier, this method was capable of screening for anaemia (<11.0g/dL haemoglobin concentration) vs healthy blood haemoglobin concentration (≥11.0g/dL) with a sensitivity of 92.9% (95% CI 66.1% to 99.8%), a specificity of 89.7% (72.7% to 97.8%) when acting on unseen data, using only an affordable smartphone and no additional hardware. Conclusion These results add to the body of evidence suggesting that smartphone colorimetry is likely to be a useful tool for making anaemia screening more widely available. However, there remains no consensus on the optimal method for image preprocessing or feature extraction, especially across diverse patient populations
Evaluating services for perinatal asphyxia and low birth weight at two hospitals in Ghana: a micro-costing analysis
Background: Neonatal mortality has been decreasing slowly in Ghana despite investments in maternal-newborn services. Although community-based interventions are effective in reducing newborn deaths, hospital-based services provide better health outcomes.Objective: To examine the process and cost of hospital-based services for perinatal asphyxia and low birth weight/preterm at a district and a regional level referral hospital in Ghana.Methods: A cross-sectional study was conducted at 2 hospitals in Greater Accra Region during May-July 2016. Term infants with perinatal asphyxia and low birth weight/preterm infants referred for special care within 24hours after birth were eligible. Time-driven activity-based costing (TDABC) approach was used to examine the process and cost of all activities in the full cycle of care from admission until discharge or death. Costs were analysed from health provider’s perspective.Results: Sixty-two newborns (perinatal asphyxia 27, low-birth-weight/preterm 35) were enrolled. Cost of care was proportionately related to length-of-stay. Personnel costs constituted over 95% of direct costs, and all resources including personnel, equipment and supplies were overstretched.Conclusion: TDABC analysis revealed gaps in the organization, process and financing of neonatal services that undermined the quality of care for hospitalized newborns. The study provides baseline cost data for future cost-effectiveness studies on neonatal services in Ghana.Keywords: perinatal asphyxia; low-birth-weight; time-driven activity-based costing; process of careFunding: Authors received no external funding for the stud
Smoke-Free Policy in Vermont Public Housing Authorities
Introduction. Millions of adults and children living in public housing face exposure to second hand smoke from adjacent apartments. These tenants are less able to escape smoke exposure by moving, and Housing Authorities are beginning to implement smoke-free policies. We assessed the status of smoke-free policy in Vermont public housing, and explored the experience of tenants and managers in Burlington who recently implemented such a policy.https://scholarworks.uvm.edu/comphp_gallery/1080/thumbnail.jp
Construction of a temperature controlled Rheo-NMR measuring cell - Influence of fluid dynamics on PMMA-polymerization kinetics
Use of microlysimeters to measure evaporation from sandy soils
Evaporation from soil can be a major component of crop water balance and land surface energy balance. A number of different applications of the microlysimeter method to measure evaporation from soil have been used in recent studies. Microlysimeters were used extensively in three sandy soils for this study. Measurement of evaporation from microlysimeters with different dimensions and of different ages allows discussion of the sources of error inherent in the method.
The evaporation recorded from microlysimeters of diameters 214 mm, 152 mm and 51 mm was not significantly different. A comparison of 100 mm and 200 mm deep microlysimeters showed that depth had no significant influence during the first 2 days after extraction from the soil profile. For periods beginning 2 or more days after rain, significant differences in evaporation owing to depth may not occur for up to 7 days. Soil cores extracted at different times showed significant differences in evaporation immediately following a rain event, and no significant differences 2 or more days thereafter. This period of significant difference was extended to about 4 days when the method was used within a crop (i.e. root extraction of water in the field significant). A protocol for use of microlysimeters is developed from these results
- …