Actual and Shadow Prices in Linear Programming. ESRI Memorandum Series No. 74 1970

There is some confusion in the literature as to the meaning of shadow prices in linear programming. This note is an attempt at clarification. In general (except for here calling it the objective function instead of preference!) we follow Geary and McCarthy (1964), usually with indication of page but with a slight but obvious change in notation. We place ourselves at the start in the simplest conceivable situation economically and mathematically (the latter in postulating that in the Primal the problem is one of maximum the constraint vector b having all elements positive and all constraint potential inequalities, i. e. all with sign "<" and no "=", which is complicating

User's manual for the REEDM (Rocket Exhaust Effluent Diffusion Model) computer program

The REEDM computer program predicts concentrations, dosages, and depositions downwind from normal and abnormal launches of rocket vehicles at NASA's Kennedy Space Center. The atmospheric dispersion models, cloud-rise models, and other formulas used in the REEDM model are described mathematically Vehicle and source parameters, other pertinent physical properties of the rocket exhaust cloud, and meteorological layering techniques are presented as well as user's instructions for REEDM. Worked example problems are included

Program listing for the REEDM (Rocket Exhaust Effluent Diffusion Model) computer program

The program listing for the REEDM Computer Program is provided. A mathematical description of the atmospheric dispersion models, cloud-rise models, and other formulas used in the REEDM model; vehicle and source parameters, other pertinent physical properties of the rocket exhaust cloud and meteorological layering techniques; user's instructions for the REEDM computer program; and worked example problems are contained in NASA CR-3646

The effectiveness of youth centers in increasing use of sexual and reproductive health services: a systematic review.

This study presents findings from a systematic review of the evidence regarding the effectiveness of youth centers in increasing use of sexual and reproductive health (SRH) services in lower- and middle-income countries. Evidence from peer-reviewed and gray literature between 1990 and 2010 was reviewed. After the screening of 3,769 citations, 21 studies reporting on 17 youth center programs were included, and were ranked by strength of evidence. Considerable consistency in findings across studies was observed. Youth centers generally served a relatively small proportion of young people living nearby. The main users were young men attending school or college, with a significant proportion older than the target age. Users of the on-site SRH services were predominantly young women, with a significant proportion older than the target age group. Uptake of services was generally low. Despite widespread emphasis on youth centers as a strategy for encouraging young people to access SRH services, results from these studies have not been encouraging, and cost-effectiveness for these purposes is likely to be low

Mathematics difficulties in extremely preterm children : evidence of a specific deficit in basic mathematics processing

Background: Extremely preterm (EP, <26 wk gestation) children have been observed to have poor academic achievement in comparison to their term-born peers, especially in mathematics. This study investigated potential underlying causes of this difficulty. Methods: A total of 219 EP participants were compared with 153 term-born control children at 11 y of age. All children were assessed by a psychologist on a battery of standardized cognitive tests and a number estimation test assessing children’s numerical representations. Results: EP children underperformed in all tests in comparison with the term controls (the majority of Ps < 0.001). Different underlying relationships between performance on the number estimation test and mathematical achievement were found in EP as compared with control children. That is, even after controlling for cognitive ability, a relationship between number representations and mathematical performance persisted for EP children only (EP: r = 0.346, n = 186, P < 0.001; control: r = 0.095, n = 146, P = 0.256). Conclusion: Interventions for EP children may target improving children’s numerical representations in order to subsequently remediate their mathematical skills

Diabatic forcing and initialization with assimilation of cloud and rain water in a forecast model: Methodology

The focus of this part of the investigation is to find one or more general modeling techniques that will help reduce the time taken by numerical forecast models to initiate or spin-up precipitation processes and enhance storm intensity. If the conventional data base could explain the atmospheric mesoscale flow in detail, then much of our problem would be eliminated. But the data base is primarily synoptic scale, requiring that a solution must be sought either in nonconventional data, in methods to initialize mesoscale circulations, or in ways of retaining between forecasts the model generated mesoscale dynamics and precipitation fields. All three methods are investigated. The initialization and assimilation of explicit cloud and rainwater quantities computed from conservation equations in a mesoscale regional model are examined. The physical processes include condensation, evaporation, autoconversion, accretion, and the removal of rainwater by fallout. The question of how to initialize the explicit liquid water calculations in numerical models and how to retain information about precipitation processes during the 4-D assimilation cycle are important issues that are addressed. The explicit cloud calculations were purposely kept simple so that different initialization techniques can be easily and economically tested. Precipitation spin-up processes associated with three different types of weather phenomena are examined. Our findings show that diabatic initialization, or diabatic initialization in combination with a new diabatic forcing procedure, work effectively to enhance the spin-up of precipitation in a mesoscale numerical weather prediction forecast. Also, the retention of cloud and rain water during the analysis phase of the 4-D data assimilation procedure is shown to be valuable. Without detailed observations, the vertical placement of the diabatic heating remains a critical problem

Uporaba Rayleighjevih valov in odziva vodostajev v vodnjakih za izračun poroznosti kamnine v Edwardsovem vodonosniku, južni in osrednji Teksas, ZDA

We use the magnitude and centroid period of Rayleigh wave along with the amplitude of fluctuations of water level in a well to calculate effective porosity of a karst aquifer at the site scale. The radial and vertical displacements of Rayleigh wave are first related to the confining pressure of rock, which is then related to fluid pressure via the Gassmann equation. Three seismograms recorded at station 633A of the USARRAY and the induced responses of Well J-17 in the Edwards Aquifer (Texas) allow the calculation of an effective porosity between 17.0 and 24.4 percent, the average of which is close to the total porosity of core samples determined by geophysical well logs. This paper provides an innovative method to measure effective porosity in aquifers. Because of the long wavelengths of Rayleigh wave, the interdisciplinary approach is advantageous in that the resulting effective porosity is at the site scale which includes large conduits or voids.Za izračun efektivne poroznosti kraškega vodonosnika na lokalni ravni smo uporabili velikost in centroidno časovno vrednost Rayleighjevega valovanja, skupaj z amplitudo nihanja vodne gladine v vrtini. Radialni in vertikalni premiki Rayleighjevega valovanja so najprej povezani s tlakom neprepustne kamnine, ki je nato z Gassmannovo enačbo povezan s tlakom tekočine. Trije seizmogrami, evidentirani na postaji 633A USARRAY, in inducirani odzivi vrtine J-17 v vodonosniku Edwards (v Teksasu) omogočajo izračun efektivne poroznosti med 17,0 in 24,4 odstotka, povprečje teh vrednosti pa je blizu poroznosti jedra v vzorcih, ki so bili določeni z geofizikalnimi meritvami v vrtinah. V prispevku je predstavljena inovativna metoda za merjenje efektivne poroznosti v vodonosnikih. Zaradi dolgih valovnih dolžin Rayleighjevega valovanja je interdisciplinarni pristop ugoden, saj efektivna poroznost obravnavanega območja vključuje velike kanale ali praznine

Rayleigh wave and well head response to calculate porosity in the edwards aquifer of South-Central Texas, USA = Uporaba rayleighjevih valov in odziva vodostajev v vodnjakih za izračun poroznosti kamnine v edwardsovem vodonosniku, južni in Osrednji Teksas, ZDA

We use the magnitude and centroid period of Rayleigh wave along with the amplitude of fluctuations of water level in a well to calculate effective porosity of a karst aquifer at the site scale. The radial and vertical displacements of Rayleigh wave are first related to the confining pressure of rock, which is then related to fluid pressure via the Gassmann equation. Three seismograms recorded at station 633A of the USARRAY and the induced responses of Well J-17 in the Edwards Aquifer (Texas) allow the calculation of an effective porosity between 17.0 and 24.4 percent, the average of which is close to the total porosity of core samples determined by geophysical well logs. This paper provides an innovative method to measure effective porosity in aquifers. Because of the long wavelengths of Rayleigh wave, the interdisciplinary approach is advantageous in that the resulting effective porosity is at the site scale which includes large conduits or voids