650 research outputs found
Development of the fast neutron imaging telescope
We report on the development of a next generation neutron telescope, with imaging and energy measurement capabilities, sensitive to neutrons in the 2-20 MeV energy range. The Fast Neutron Imaging Telescope (FNIT) was initially conceived to study solar neutrons as a candidate instrument for the Inner Heliosphere Sentinels (IHS) program under formulation at NASA. This detector is now being adapted to locate Special Nuclear Material (SNM) for homeland security purposes by detecting fission neutrons and reconstructing the image of their source. In either case, the detection principle is based on multiple elastic neutron-proton scatterings in organic scintillator. By reconstructing the scattering coordinates and measuring the recoil proton energy, the direction and energy of each neutron can be determined and discrete neutron sources identified. We describe the performance of the FNIT prototype, report on the current status of R&D efforts and present the results of recent laboratory measurements
Atmospheric neutron measurements with the SONTRAC science model
–The SOlar Neutron TRACking (SONTRAC) telescope was originally developed to measure the energy spectrum and incident direction of neutrons produced in solar flares, in the energy range 20 - 250 MeV. While developed primarily for solar physics, the SONTRAC detector may be employed in virtually any application requiring both energy measurement and imaging capabilities. The SONTRAC Science Model (SM) is presently being operated at the University of New Hampshire (UNH) as a ground-based instrument to investigate the energy spectrum, zenith and azimuth angle dependence of the cosmic-ray induced sea-level atmospheric neutron flux. SONTRAC measurements are based on the non-relativistic double scatter of neutrons off ambient protons within a block of scintillating fibers. Using the n-p elastic double-scatter technique, it is possible to uniquely determine the neutron’s energy and direction on an event-by-event basis. The 3D SM consists of a cube of orthogonal plastic scintillating fiber layers with 5 cm sides, read out by two CCD cameras. Two orthogonal imaging chains allow full 3D reconstruction of scattered proton tracks
Design optimization and performance capabilities of the fast neutron imaging telescope (FNIT)
We describe the design optimization process and performance characterization of a next generation neutron telescope, with imaging and energy measurement capabilities, sensitive to neutrons in the 1-20 MeV energy range. The response of the Fast Neutron Imaging Telescope (FNIT), its efficiency in neutron detection, energy resolution and imaging capabilities were characterized through a combination of lab tests and Monte Carlo simulations. Monte Carlo simulations, together with experimental data, are also being used in the development and testing of the image reconstruction algorithm. FNIT was initially conceived to study solar neutrons as a candidate instrument for the Inner Heliosphere Sentinel (IHS) spacecraft. However, the design of this detector was eventually adapted to locate Special Nuclear Material (SNM) sources for homeland security purposes, by detecting fission neutrons. In either case, the detection principle is based on multiple elastic neutron-proton scatterings in organic scintillator. By reconstructing event locations and measuring the recoil proton energies, the direction and energy spectrum of the primary neutron flux can be determined and neutron sources identified. This paper presents the most recent results arising from our efforts and outlines the performance of the FNIT detector
The ability of a limited metabolic assessment to identify pediatric stone formers with metabolic abnormalities
Introduction
American Urological Association guidelines recommend a urinary metabolic evaluation after the first stone event in all pediatric stone patients. Prior studies identified hypercalciuria and urine hypovolemia as the most common abnormalities in children with urolithiasis. Recent data suggest that hypocitraturia is most prevalent. It was hypothesized that a limited evaluation would detect the majority of clinically significant metabolic abnormalities in pediatric stone formers.
Material and methods
A retrospective analysis of all children (<18 years of age) with renal/ureteral calculi evaluated at the study institution from 2005 to 2015 was performed. Children with ≥ one 24-h urinary metabolic profile after a clinical visit for renal/ureteral calculi were included. Those with bladder stones and those with undercollection or overcollection or missing urinary creatinine were excluded. Demographics and data from the first urinary metabolic profile and stone analyses were collected. The sensitivity, specificity, and positive and negative predictive value (NPV) of a limited urinary metabolic evaluation consisting of four parameters (24-h calcium, citrate, and oxalate and low urinary volume) were compared to a complete urinary metabolic profile. The number and type of metabolic abnormalities that would have been missed with this limited evaluation weredetermined.
Results
Of 410 patients, 21 were excluded for age ≥18 years, 13 for bladder stones, 248 for overcollections, 38 for undercollections, and 10 for missing creatinine. This left 80 patients for inclusion: median age 11.4 years, 60% female, and 96.3% white. Of the entire cohort, 69.6% had hypocitraturia, 52.5% had low urine volume, and 22.5% had hypercalciuria. Sensitivity was 87.5%. Specificity could not be calculated because no patients had a normal complete metabolic evaluation. The NPV was zero, and the positive predictive value was 100%, but these are artifacts resulting from the absence of patients with a normal complete metabolic evaluation. Of the 80 patients, 10 had at least one abnormality missed by a limited metabolic evaluation (Table 1). The missed abnormalities were high pH (n = 6), abnormal 24-h phosphorus (low in 1 patient and high in 1 patient), low 24-h magnesium (n = 3), low 24-h potassium (n = 3), and high 24-h sodium (n = 4).
Discussion
A limited urinary metabolic evaluation would have detected the vast majority of clinically significant metabolic abnormalities in the study sample. Approximately two-thirds of the study patients submitted inadequate 24-h urine specimens.
Conclusions
A simplified approach to metabolic evaluation in first-time stone formers with a stone analysis available was proposed. This streamlined approach could simplify the metabolic evaluation and reduce health care costs
Initial collection of an inadequate 24-hour urine sample in children does not predict subsequent inadequate collections
Introduction
Approximately half of adult stone formers submit specimens that are either under or over collections as determined by 24-h creatinine/kg. Previously identified predictors of inadequate collection in adults include female sex, older age, higher body mass index (BMI), vitamin D supplementation, and weekday collection.
Objective
The objective of this study is to determine risk factors for inadequate 24-h urinary specimen collection in the pediatric population.
Study design
A retrospective analysis of all children (<18 years of age) with renal and/or ureteral calculi evaluated at the study tertiary care pediatric center from 2005 to 2015 was performed. Those who had at least one 24-h urinary metabolic profile after a clinical visit for kidney and/or ureteral stones were included; children with bladder stones were excluded. Adequate collections had a urine creatinine of 10–15 mg/kg/24 h. A bivariate analysis of potential factors associated with inadequate collection of the initial urinary metabolic profile, including child demographics, parental socio-economic factors, history of stone surgery, and weekday vs. weekend urine collection, was performed. A mixed-effects logistic regression, controlling for correlation of specimens from the same patient, was also performed to determine whether an initial inadequate collection predicted a subsequent inadequate collection.
Results
Of 367 patients, 80 had an adequate collection (21.9%): median age, 13 years (interquartile range, 8–16); 61.1% female; 93.5% white; 19.5% obese; and 13.0% overweight. No parental or child factors were associated with inadequate collection (Summary Table). Of inadequate collections, more than 80% were over collections. In the 175 patients with more than one 24-h urinary specimen collection, the effect of an initial inadequate collection on subsequent inadequate collections was not significant after controlling for the correlation of samples from the same patient (p = 0.8).
Discussion
Any parental or child factors associated with the collection of inadequate 24-h urine specimens in children were not found. An initial inadequate collection does not predict subsequent inadequate collections. It was surprising that >80% of the inadequate collections were over collections rather than under collections. Possible explanations are that children collected urine samples for longer than the 24-h period or that stone-forming children produce more creatinine per 24-h period than healthy children due to hyperfiltration.
Conclusion
Inadequate collections are very common, and the risk factors for them are unclear. A repeat collection would be suggested if the first is inadequate. Further studies must be planned to explore barriers to accurate specimen collection using qualitative research methodology
Genetic Variance and Covariance Components for Feed Intake, Average Daily Gain, and Postweaning Gain in Growing Beef Cattle
Feed is the greatest cost for a beef cattle production enterprise. Data collection to determine feed efficiency of animals is also costly, because both gain and intake records are needed to calculate feed efficiency. Electronic intake monitoring systems such as GrowSafe or Insentec to collect feed intake data are expensive and thus limit the number of animals that can be tested. Scientists have worked to pinpoint optimal test durations for collecting both weight gain and feed intake records to lessen costs.
A 70-day performance test is currently recommended for accurate calculation of efficiency, with growth data as the limiting factor. Research has suggested that a 35-day test is adequate to measure feed intake, but a test period of at least 70 days is suggested to measure gain with sufficient accuracy. The objective of this study was to estimate genetic parameters for growth and intake traits with particular attention to the relationship between on-test average daily gain (ADG) and national cattle evaluation postweaning gain (PWG). If the correlation between these two traits is strong, it could allow for the use of PWG as a proxy for ADG in the genetic evaluation of feed efficiency. This substitution would allow producers to reduce the length of the test required to measure feed intake accurately
The L&E of Intellectual Property – Do we get maximum innovation with the current regime?
Innovation is crucial to economic growth – the essential path for lifting much of the world population out of dire poverty and for maintaining the living standard of those who already have. To stimulate innovation, the legal system has to support the means through which innovators seek to get rewarded for their efforts. Amongst these means, some, such as the first mover advantage or 'lead time,' are not directly legal; but secrets and intellectual property rights are legal institutions supported for the specific purpose of stimulating innovation. Whilst the protection of secrets has not changed very much over recent years, intellectual property (or IP) has. IP borrows some features from ordinary property rights, but is also distinct, in that, unlike physical goods, information, the object of IP, is not inherently scarce; indeed as information and communication technologies expand, the creation and distribution of information is becoming ever cheaper and in many circumstances abundant, so that selection is of the essence ('on the internet, point of view is everything'). Where rights on information extend too far, their monopolising effect may hamper innovation.
The paper investigates the underlying structure of IP rights and surveys what we know empirically about the incentive effects of IP as about industries that flourish without formal IP
Comparison of Intraoperative and Early Postoperative Outcomes of Caudal Versus Dorsal Penile Nerve Blocks for Outpatient Penile Surgeries
Objective
To compare intraoperative and 1-hour postoperative outcomes in caudal versus dorsal penile nerve block (DPNB) patients undergoing penile surgeries.
Material and Methods
We performed a retrospective cohort study of males 3. Secondary outcomes were intraoperative/post-anesthesia care unit (PACU) narcotics, pre-incision anesthesia time, adjusted operating room charges and complications. We performed bivariate and multivariable analyses controlling for demographic/procedure characteristics and clustering by surgeon.
Results
Of 738 patients, (mean age 2.1 years) 74.1% had a caudal. DPNB patients were more likely to have a maximum pain score >3 (19.5% vs. 8.1%, p 3 (95% CI 1.7- 4.4, p<0.0001) and 5.2 times the odds of intraoperative/PACU narcotic administration (95% CI 3.3-8.1, p<0.0001). In multivariable analyses, caudal patients had longer pre-incision anesthesia time (27.9 ± 7.4 vs. 19.5 ± 6.6 minutes, p<0.0001) and higher adjusted operating room charges (9,402 ± 3741, p=0.01).
Conclusion
Caudal blocks may offer a small advantage in the immediate postoperative period although cost-effectiveness is unproven
Potential Impact of Amantadine on Aggression in Chronic Traumatic Brain Injury
Objective: To assess the effects of amantadine on anger and aggression among individuals with a chronic traumatic brain injury (TBI).
Methods: A cohort of 118 persons with chronic TBI (>6 months postinjury) and moderate-severe aggression selected from a larger cohort of 168 participants enrolled in a parallel-group, randomized, double-blind, placebo-controlled trial of amantadine 100 mg twice daily (n = 82) versus placebo (n = 86) for treatment of irritability were studied. Anger and aggression were measured at treatment days 0, 28, and 60 using observer-rated and participant-rated State-Trait Anger Expression Inventory-2 (STAXI-2) and Neuropsychiatric Inventory-Agitation/Aggression domain (NPI-A) Most Problematic and Distress scores.
Results: Participant-rated day 60 NPI-A Most Problematic (adjusted P = .0118) and NPI-A Distress (adjusted P = .0118) were statistically significant between the 2 groups, but STAXI-2 differences were not significant after adjustment for multiple comparisons. Substantial improvements were noted in both amantadine and placebo groups (70% vs 56% improving at least 3 points on day 60 Observer NPI-A; P = .11).
Conclusion: Amantadine 100 mg twice daily in this population with chronic TBI appears to be beneficial in decreasing aggression from the perspective of the individual with TBI. No beneficial impact on anger was found
Practices and Challenges of Growth Monitoring and Promotion in Ethiopia: A Qualitative Study
The use of growth monitoring and promotion (GMP) has become widespread.
It is a potential contributor towards achieving the Millennium
Development Goals of halving hunger and reducing child mortality by
two-thirds within 2015. Yet, GMP appears to be a prerequisite for good
child health but several studies have shown that there is a discrepancy
between the purpose and the practice of GMP. The high prevalence of
malnutrition in many developing countries seems to confirm this fact. A
descriptive qualitative study was carried out from April to September
2011. Focus group discussions and in-depth interviews were conducted
amongst mothers and health workers. Data were analyzed using a
qualitative content analysis technique, with the support of ATLAS.ti
5.0 software. The results suggest that most mothers were aware of the
need for regular weight monitoring while health workers also seemed to
be well-aware and to practise GMP according to the international
guidelines. However, there was a deficit in maternal knowledge with
regard to child-feeding and a lack of basic resources to keep and/or to
buy healthful and nutritionally-rich food. Furthermore, the role of the
husband was not always supportive of proper child-feeding. In general,
GMP is unlikely to succeed if mothers lack awareness of proper
child-feeding practices, and if they are not supported by their
husbands
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