The effects of atmosphere conditions on gamma-ray astronomy

The High Energetic Stereoscopic System (H.E.S.S.) experiment is an array of imaging atmospheric Cherenkov (IAC) telescopes of the next generation, with enlarged mirrors and advanced detector electronics compared to its predecessors. As a member of the international H.E.S.S. collaboration, the Durham 7-rау astronomy group took over the responsibility for design, construction and commissioning of calibration systems for the H.E.S.S. telescopes and atmospheric monitoring devices. The atmosphere is an essential part of the detector system for the IAC technique, monitoring of the atmosphere's parameter is therefore important for energy calibration of the detector and variability studies of 7-ray sources to distinguish between detector and source fluctuations. A weather station, several infrared radiometers and an infrared LIDAR system have been installed to provide constant monitoring of all relevant parameters. This thesis reports about the work performed for the design and commissioning of the calibration module. Furthermore, the technicalities of the LIDAR system and the IR radiometer, their use in terms of 7-ray astronomy, especially studies about the variability of zenith angle dependencies and the correlation with other atmospheric parameters and telescope trigger rates are discussed

Development of an Instrumentation System for a Laboratory Model Food Product Dryer

To achieve optimal dryer performance, the process parameters required for both the optimization and control of the drying process must be made available via the instrumentation system. A few works have been reported on the development of instrumentation systems for handling drying system parameters. Out of which, some are deficient in the number of drying process parameters that can be handled, while others are unreliable and inaccurate. Therefore, there is the need to develop a microcontroller-based instrumentation system that can monitor, measure, control, display and store the main drying process parameters and sample weight with a high degree of reliability and accuracy. In this study, the sensors were selected based on system specifications and interfaced with the microcontroller. The codes for controlling, logging and displaying of drying parameters were developed and installed on the microcontroller. When tested at steady-state conditions, the system yielded satisfactory results with maximum control and detection errors being 2.0% and 1.8% for the temperature and sample weight, respectively. The developed system can be used for efficient computation of both the dry and wet basis sample moisture content values and also detect the set sample weight. Keywords— Dryer, Drying parameters, Instrumentation system, Moisture content, Sensor

Mars Reconnaissance Orbiter Context Camera Updated In-Flight Calibration

The image data of the Context Camera (CTX) of the Mars Reconnaissance Orbiter require a flat-field correction that is currently available as a plain text file in the Planetary Data System “Calib” folders for all CTX Enhanced Data Record releases or automatically implemented as part of the ctxcal application of the Integrated Software for Images and Spectrometers (ISIS). We noticed (a) differences between these two flat-fields and (b) residual edge darkening (vignetting) after applying ctxcal. This work examines in detail the edge-darkening effect over time and creates a new improved flat-field calibration file to be implemented into the ISIS ctxcal application as a new default. We introduce a method to quantify the vignetting effect and its residuals after regular ISIS calibration. With the old calibration, the amount of residual edge-darkening is about eight percent. We prove that the new calibration does remove the effect completely, does not introduce any artifacts and qualitatively and quantitatively validate newly calibrated images. Mosaics produced with images that have been calibrated with our new flatfield show immediately less striping issues, without the application of any standard mosaicking-related tone-matching techniques

Planet Four: Terrains - Discovery of Araneiforms Outside of the South Polar Layered Deposits

We present the results of a systematic mapping of seasonally sculpted terrains on the South Polar region of Mars with the Planet Four: Terrains (P4T) online citizen science project. P4T enlists members of the general public to visually identify features in the publicly released Mars Reconnaissance Orbiter CTX images. In particular, P4T volunteers are asked to identify: 1) araneiforms (including features with a central pit and radiating channels known as 'spiders'); 2) erosional depressions, troughs, mesas, ridges, and quasi-circular pits characteristic of the South Polar Residual Cap (SPRC) which we collectively refer to as 'Swiss cheese terrain', and 3) craters. In this work we present the distributions of our high confidence classic spider araneiforms and Swiss cheese terrain identifications. We find no locations within our high confidence spider sample that also have confident Swiss cheese terrain identifications. Previously spiders were reported as being confined to the South Polar Layered Deposits (SPLD). Our work has provided the first identification of spiders at locations outside of the SPLD, confirmed with high resolution HiRISE imaging. We find araneiforms on the Amazonian and Hesperian polar units and the Early Noachian highland units, with 75% of the identified araneiform locations in our high confidence sample residing on the SPLD. With our current coverage, we cannot confirm whether these are the only geologic units conducive to araneiform formation on the Martian South Polar region. Our results are consistent with the current CO2 jet formation scenario with the process exploiting weaknesses in the surface below the seasonal CO2 ice sheet to carve araneiform channels into the regolith over many seasons. These new regions serve as additional probes of the conditions required for channel creation in the CO2 jet process. (Abridged)Comment: accepted to Icarus - Supplemental data files are available at https://www.zooniverse.org/projects/mschwamb/planet-four-terrains/about/results - Icarus print version available at http://www.sciencedirect.com/science/article/pii/S001910351730055

Longitudinal evaluation of cognitive functioning in young children with type 1 diabetes over 18 months

OBJECTIVE: Decrements in cognitive function may already be evident in young children with type 1 diabetes (T1D). Here we report prospectively acquired cognitive results over 18 months in a large cohort of young children with and without T1D. METHODS: 144 children with T1D (mean HbA1c: 7.9%) and 70 age-matched healthy controls (mean age both groups 8.5 years; median diabetes duration 3.9 yrs; mean age of onset 4.1 yrs) underwent neuropsychological testing at baseline and after 18-months of follow-up. We hypothesized that group differences observed at baseline would be more pronounced after 18 months, particularly in those T1D patients with greatest exposure to glycemic extremes. RESULTS: Cognitive domain scores did not differ between groups at the 18 month testing session and did not change differently between groups over the follow-up period. However, within the T1D group, a history of diabetic ketoacidosis (DKA) was correlated with lower Verbal IQ and greater hyperglycemia exposure (HbA1c area under the curve) was inversely correlated to executive functions test performance. In addition, those with a history of both types of exposure performed most poorly on measures of executive function. CONCLUSIONS: The subtle cognitive differences between T1D children and nondiabetic controls observed at baseline were not observed 18 months later. Within the T1D group, as at baseline, relationships between cognition (VIQ and executive functions) and glycemic variables (chronic hyperglycemia and DKA history) were evident. Continued longitudinal study of this T1D cohort and their carefully matched healthy comparison group is planned

Recovery of hypothalamo–pituitary–adrenal axis suppression during treatment with inhaled corticosteroids for childhood asthma

Objective: To describe recovery of adrenal insufficiency in asthmatic children treated with inhaled corticosteroids (ICS) and cortisol replacement therapy. Design: Retrospective, observational study. Patients: A total of 113 patients, 74 male; age 10.4 (3.3–16.5) years; beclomethasone-­equivalent ICS dose, 800 µg, (100–1,000), tested by low dose short Synacthen (tetracosactide) test (LDSST), were studied. Test results were classified by basal and peak cortisol concentration: “normal” (basal >100 nmol/L, peak >500 nmol/L), “suboptimal” (basal >100 nmol/L, peak 350–499 nmol/L), “abnormal” (basal 15% [2× the inter-assay coefficient of variation]), change in BMI and height standard deviation score (SDS). Results: Baseline test results were abnormal in 17 patients (15%) and all of them had repeat tests. In 13 patients (76%), test results improved (normal in six, suboptimal in seven) and four (24%) remained abnormal. Baseline tests results were suboptimal in 54 patients (48%), of whom 50 (93%) were retested. Repeat tests were normal in 36 patients (72%), remained suboptimal in 11 (22%), and were abnormal in three (6%). Baseline tests results were normal in 42 patients, of whom six patients (14%) were retested. Results remained normal in three (50%), were suboptimal in two (33%), and abnormal in one (17%). Basal and peak cortisol levels increased by >15% in 33/73 (45%) and 42/73 (57%) patients, respectively, and decreased by >15% in 14/73 (19%) and 7/73 (10%), respectively. There was no significant change in height or BMI SDS. Conclusion: Recovery of adrenal function is common and occurs during continued ICS and cortisol replacement therapy

Planet Four: A Neural Network’s search for polar spring-time fans on Mars

Dark deposits visible from orbit appear in the Martian south polar region during the springtime. These are thought to form from explosive jets of carbon dioxide gas breaking through the thawing seasonal ice cap, carrying dust and dirt which is then deposited onto the ice as dark ‘blotches’, or blown by the surface winds into streaks or ‘fans’. We investigate machine learning (ML) methods for automatically identifying these seasonal features in High Resolution Imaging Science Experiment (HiRISE) satellite imagery. We designed deep Convolutional Neural Networks (CNNs) that were trained and tested using the catalog generated by Planet Four, an online citizen science project mapping the south polar seasonal deposits. We validated the CNNs by comparing their results with those of ISODATA (Iterative Self-Organizing Data Analysis Technique) clustering and as expected, the CNNs were significantly better at predicting the results found by Planet Four, in both the area of predicted seasonal deposits and in delineating their boundaries. We found neither the CNNs or ISODATA were suited to predicting the source point and directions of seasonal fans, which is a strength of the citizen science approach. The CNNs showed good agreement with Planet Four in cross-validation metrics and detected some seasonal deposits in the HiRISE images missed in the Planet Four catalog; the total area of seasonal deposits predicted by the CNNs was 27% larger than that of the Planet Four catalog, but this aspect varied considerably on a per-image basis

Productivity and profitability of small-scale tilapia aquaculture in Myanmar

To promote the sustainable development of aquaculture in Myanmar, WorldFish and its partners implemented the Scaling Systems and Partnerships for Accelerated Adoption of Improved Tilapia Strains (SPAITS) project, funded by the German Federal Ministry for Economic Cooperation and Development and commissioned by the Deutsche Gesellschaft für Internationale Zusammenarbeit through the Fund International Agricultural Research. The goal was to increase the adoption of improved tilapia strains among poor fish producers and deliver improved productivity and profitability of small-scale aquaculture so that poor producers, particularly women, are able to exit poverty and natural resource systems are improved to sustain future fish production. The project’s purpose is to design systems that accelerate the dissemination and adoption of improved tilapia strains and aquaculture management practices developed by WorldFish, based on relevant gender-sensitive and contextual knowledge, that will enable poor small-scale fish farmers to have access to, adopt and benefit from improved strains of tilapia. As an activity of the project, this study focuses on assessing the performance of small-scale tilapia aquaculture operated by aquaculture households in Myanmar