A knowledge-based expert system for scheduling of airborne astronomical observations

The Kuiper Airborne Observatory Scheduler (KAOS) is a knowledge-based expert system developed at NASA Ames Research Center to assist in route planning of a C-141 flying astronomical observatory. This program determines a sequence of flight legs that enables sequential observations of a set of heavenly bodies derived from a list of desirable objects. The possible flight legs are constrained by problems of observability, avoiding flyovers of warning and restricted military zones, and running out of fuel. A significant contribution of the KAOS program is that it couples computational capability with a reasoning system

Mechanism of salinity change and hydrogeochemical evolution of groundwater in the Machile-Zambezi Basin, South-western Zambia

Machile-Zambezi Basin, South-Western Zambia hosts high salinity groundwater which threatens water security for rural inhabitants. This study investigates the hydrological mechanism that led to high salinity and the geochemical evolution of the groundwater system. The Machile-Zambezi Basin is part of the wider Kalahari Basin which underwent major palaeo-environmental climatic, tectonic and sedimentology dynamics which must have impacted the groundwater salinity. The study examines the groundwater level, hydrochemistry, environmental isotopes (18O/16O, 2H/1H, 3H/3He, 14C/13C). In addition, the sediment cation exchange capacity (CEC) and pore-water chemistry on intact core material were measured. The groundwater chemistry evolved from fresh Ca(Na)HCO3 to saline Na(Ca, Mg)SO4 due to dissolution of salts and not evaporation as indicated by stable isotopes. The saline groundwater is old with 14C ages estimates of more than 1000 years old and stagnant. Geochemical modelling using PHREEQC suggests that ionic exchange due to release of cations from dissolving salts and sulphate reduction were also important processes in this system. High groundwater salinity is therefore associated with Pre-Holocene environmental changes and is restricted to a stagnant saline zone. It will therefore remain unflushed as long as current climatic conditions remain

Controlled Delivery of Sdf-1 Alpha and Igf-1: Cxcr4(+) Cell Recruitment and Functional Skeletal Muscle Recovery

Therapeutic delivery of regeneration-promoting biological factors directly to the site of injury has demonstrated its efficacy in various injury models. Several reports describe improved tissue regeneration following local injection of tissue specific growth factors, cytokines and chemokines. Evidence exists that combined cytokine/growth factor treatment is superior for optimizing tissue repair by targeting different aspects of the regeneration response. The purpose of this study was to evaluate the therapeutic potential of the controlled delivery of stromal cell-derived factor-1alpha (SDF-1 alpha) alone or in combination with insulin-like growth factor-I (SDF-1 alpha/IGF-I) for the treatment of tourniquet-induced ischemia/reperfusion injury (TK-I/R) of skeletal muscle. We hypothesized that SDF-1 alpha will promote sustained stem cell recruitment to the site of muscle injury, while IGF-I will induce progenitor cell differentiation to effectively restore muscle contractile function after TK-I/R injury while concurrently reducing apoptosis. Utilizing a novel poly-ethylene glycol PEGylated fibrin gel matrix (PEG-Fib), we incorporated SDF-1 alpha alone (PEG-Fib/SDF-1 alpha) or in combination with IGF-I (PEG-Fib/SDF-1 alpha/IGF-I) for controlled release at the site of acute muscle injury. Despite enhanced cell recruitment and revascularization of the regenerating muscle after SDF-1 alpha treatment, functional analysis showed no benefit from PEG-Fib/SDF-1 alpha therapy, while dual delivery of PEG-Fib/SDF-1 alpha/IGF-I resulted in IGF-I-mediated improvement of maximal force recovery and SDF-1 alpha-driven in vivo neovasculogenesis. Histological data supported functional data, as well as highlighted the important differences in the regeneration process among treatment groups. This study provides evidence that while revascularization may be necessary for maximizing muscle force recovery, without modulation of other effects of inflammation it is insufficient.Kinesiology and Health Educatio

An assertion language for constraint logic programs

In an advanced program development environment, such as that discussed in the introduction of this book, several tools may coexist which handle both the program and information on the program in different ways. Also, these tools may interact among themselves and with the user. Thus, the different tools and the user need some way to communicate. It is our design principie that such communication be performed in terms of assertions. Assertions are syntactic objects which allow expressing properties of programs. Several assertion languages have been used in the past in different contexts, mainly related to program debugging. In this chapter we propose a general language of assertions which is used in different tools for validation and debugging of constraint logic programs in the context of the DiSCiPl project. The assertion language proposed is parametric w.r.t. the particular constraint domain and properties of interest being used in each different tool. The language proposed is quite general in that it poses few restrictions on the kind of properties which may be expressed. We believe the assertion language we propose is of practical relevance and appropriate for the different uses required in the tools considered

The Effect of Surgical Intervention on Pediatric Burn Injury Survival in a Resource-Poor Setting

Introduction: Burns are one of the most common injuries sustained globally. Low- and middle-income countries (LMICs) are disproportionately affected by burn injury morbidity and mortality; African children have the highest burn mortality globally. In high-income countries, early surgical intervention has shown to improve survival. However, when applied to burn victims in LMICs, improved survival in the early excision cohort (≤5 d) was not seen. Therefore, we aimed to determine the magnitude of the effect of surgical intervention on burn injury survival. Methods: A retrospective analysis of a prospectively collected data, utilizing the Kamuzu Central Hospital Burn Database from May 2011 to July 2019, was performed. Pediatric patients (≤12 y) were included. Patients were excluded if they underwent surgical intervention for nonacute burn care management. Bivariate analyses stratifying by type of surgical intervention was performed, comparing demographics, burn characteristics, surgical intervention, and patient mortality. Standardized estimates were adjusted using the inverse-probability of treatment weights to account for confounding. Weighted logistic regression modeling was performed to determine the odds of mortality based on if a patient underwent surgical intervention. Results: During the study, 2364 patients were seen at the Kamuzu Central Hospital, 1785 (75.5%) were children ≤12 y who met inclusion criteria. In the overall cohort, 342 (19.2%) underwent operations, including split-thickness skin graft (n = 196, 57.3%), debridement (n = 116, 33.9%), escharotomy (n = 19, 5.6%), and amputation (n = 1, 0.3%). The surgery cohort was older (4.2 ± 3.1 versus 3.1 ± 2.6 y, P < 0.001) with larger percent total body surface area burns (16%, interquartile range: 10-24 versus 13%, interquartile range: 8-20, P < 0.001) than those who did not have surgery. In the propensity score–weighted logistic regression predicting survival, patients undergoing surgery after burn injury had an increased odds of survival (odds ratio: 5.24, 95% confidence interval: 2.40-11.44, P = 0.003) when compared with patients not undergoing surgery. Conclusions: In this propensity-weighted analysis, surgical intervention following burn injury increases the odds of survival by a factor of 5.24 when compared with patients not undergoing surgical intervention. Efforts to enhance burn infrastructure to deliver surgical care is imperative to attenuate burn mortality in resource-poor settings

Observatory's linguistic landscape: semiotic appropriation and the reinvention of space

Using a longitudinal ethnographic study of the linguistic landscape (LL) in Observatory's business corridor of Lower Main Road, the paper explores changes brought about by the influx of immigrant Africans, their artefacts and language practices. The paper uses the changes in the LL over time and the development of an "African Corner" within Lower Main Road, to illustrate the appropriation of space and the unpredictability, which comes along with highly mobile, technological and multicultural citizens. It is argued that changes in the LL are part of the act of claiming and appropriating space wherein space becomes summarily recontexualized and hence reinvented and "owned" by new actors. It is also argued that space ownership can be concealed through what we have called "brand anonymity" strategies in which the identity of the owner is deliberately concealed behind global brands. We conclude that space is pliable and mobile, and that, it is the people within space who carve out new social practices in their appropriated space.IBS

Automatic parallelization of irregular and pointer-based computations: perspectives from logic and constraint programming

Irregular computations pose some of the most interesting and challenging problems in automatic parallelization. Irregularity appears in certain kinds of numerical problems and is pervasive in symbolic applications. Such computations often use dynamic data structures which make heavy use of pointers. This complicates all the steps of a parallelizing compiler, from independence detection to task partitioning and placement. In the past decade there has been significant progress in the development of parallelizing compilers for logic programming and, more recently, constraint programming. The typical applications of these paradigms frequently involve irregular computations, which arguably makes the techniques used in these compilers potentially interesting. In this paper we introduce in a tutorial way some of the problems faced by parallelizing compilers for logic and constraint programs. These include the need for inter-procedural pointer aliasing analysis for independence detection and having to manage speculative and irregular computations through task granularity control and dynamic task allocation. We also provide pointers to some of the progress made in these áreas. In the associated talk we demónstrate representatives of several generations of these parallelizing compilers

A CO Funnel in the Galactic Centre: Molecular Counterpart of the Northern Galactic Chimney?

We report the discovery of a velocity coherent, funnel shaped ^13CO emission feature in the Galactic centre (GC) using data from the SEDIGISM survey. The molecular cloud appears as a low velocity structure (V_LSR=[-3.5, +3.5] km/s) with an angular extent of 0.95{\deg} x 1{\deg}, extending toward positive Galactic latitudes. The structure is offset from Sgr A* toward negative Galactic longitudes and spatially and morphologically correlates well with the northern lobe of the 430 pc radio bubble, believed to be the radio counterpart of the multiwavelength GC chimney. Spectral line observations in the frequency range of 85-116 GHz have been carried out using the IRAM 30 metre telescope toward 12 positions along the funnel-shaped emission. We examine the ^12C/^13C isotopic ratios using various molecules and their isotopologues. The mean ^12C/^13C isotope ratio (30.6+-2.9) is consistent with the structure located within inner 3 kpc of the Galaxy and possibly in the GC. The velocity of the molecular funnel is consistent with previous radio recombination line measurements of the northern lobe of radio bubble. Our multiwavelength analysis suggests that the funnel shaped structure extending over 100 pc above the Galactic plane is the molecular counterpart of the northern GC chimney.Comment: Accepted for publication in A&A Letter

Independence in CLP Languages

Studying independence of goals has proven very useful in the context of logic programming. In particular, it has provided a formal basis for powerful automatic parallelization tools, since independence ensures that two goals may be evaluated in parallel while preserving correctness and eciency. We extend the concept of independence to constraint logic programs (CLP) and prove that it also ensures the correctness and eciency of the parallel evaluation of independent goals. Independence for CLP languages is more complex than for logic programming as search space preservation is necessary but no longer sucient for ensuring correctness and eciency. Two additional issues arise. The rst is that the cost of constraint solving may depend upon the order constraints are encountered. The second is the need to handle dynamic scheduling. We clarify these issues by proposing various types of search independence and constraint solver independence, and show how they can be combined to allow dierent optimizations, from parallelism to intelligent backtracking. Sucient conditions for independence which can be evaluated \a priori" at run-time are also proposed. Our study also yields new insights into independence in logic programming languages. In particular, we show that search space preservation is not only a sucient but also a necessary condition for ensuring correctness and eciency of parallel execution

Pre-burn malnutrition increases operative mortality in burn patients who undergo early excision and grafting in a sub-Saharan African burn unit: methodological issues

Dear Editor in chief, Drs. Ashrafi-Asgarabad and Safiri raise several questions about the methodology we employed in our article. Thank you for this opportunity to respond to their letter