The development of employment policies for older workers

Thesis (M.B.A.)--Boston Universit

A descriptive study of hot aches:a previously unreported winter climbing phenomenon

Background: Hot aches, also known as the screaming barfies in North America, are a recognised phenomenon amongst winter climbers, assumed to be triggered by the re-perfusion of cold peripheries which then rapidly progresses to a systemic vasodilatory syndrome. Symptoms experienced in the hands include pain, numbness and throbbing followed by systemic symptoms such as nausea, irritability, dizziness and in extreme cases, a transient loss of vision and hearing. Despite being well known amongst the winter climbing community there are no publications in the scientific literature characterising the hot aches. Results: This is a descriptive epidemiological study of UK winter climbers, and their experience of hot aches. We found that hot aches are experienced by 96% of these climbers. They generally last 1-5min and 75% rate them as being 3-4 (out of 5) on a pain scale. The most common local symptoms are pain (87%), throbbing (70%) and tingling (52%). The most common systemic symptoms are nausea (44%), irritability (32%) and dizziness (20%). 20% of climbers experience hotaches in locations other than their hands. Conclusions: The hot aches are a highly predictable and consistent experience for almost all winter climbers. This study has characterised, for the first time, a recognised but previously unreported phenomenon that occurs in extreme winter climbers. The short and long term consequences of which are currently unknown, and warrant further investigation.<br/

DISTRIBUTION, DIET, AND PREVALENCE OF AMPHIBIAN CHYTRID FUNGUS IN NON-NATIVE AMERICAN BULLFROGS (LITHOBATES CATESBEIANUS) AT THE VALENTINE NATIONAL WILDLIFE REFUGE, NEBRASKA, USA

American Bullfrogs (Lithobates catesbeianus) have been widely introduced beyond their native range in North America and can negatively affect organisms in wetland environments via a suite of mechanisms including interspecific interactions and disease transmission. Bullfrogs were introduced to the Valentine National Wildlife Refuge in the Sandhill Region of Nebraska, USA, yet little is known regarding their distribution, abundance, and potential effects on other vertebrates in the Refuge. Surveys in 1991-1992 documented bullfrogs in only one lake by the Refuge headquarters, and anecdotal historical observations indicated that bullfrogs were present primarily in lakes open to public fishing. In 2012, we determined the distribution of bullfrogs across the Refuge, examined their diets, and sampled them for the occurrence of the pathogenic fungus, Batrachochytrium dendrobatidis. We documented that bullfrogs were almost ubiquitous across the Refuge lakes and wetlands. From diet analyses, we observed that adult bullfrogs consumed several vertebrate species on the Refuge including: a Blanding’s Turtle (Emydoidea blandingii), small bullfrogs, an unidentifiable frog species, and numerous invertebrates, including crayfish. The amphibian chytrid fungus was prevalent on the refuge with 73.7% of bullfrogs testing positive for the fungus in early June and 6.3% in late June-July. Preliminary data indicate that bullfrogs likely have already affected interspecific interactions with native amphibians via predation, competition, and/or disease transmission. Bullfrogs likely cannot be eradicated from the Refuge, but expanding the season of harvest of bullfrogs might reduce their abundance, which may benefit native amphibians and reptiles

An Experimental And Theoretical Investigation Into Airflow Through Air Box Of A Potato-Rock Separator

Velocity and pressure distribution in the air duct system and that over the grate of a potato-rock separator of Alan Equipment, PEI was analysed utilizing computational fluid dynamics. COMSOL software using appropriate boundary conditions was used for rapid analysis of flow through the system. To calibrate the theoretical results velocity, pressure and flow rates were measured on the actual full-scale unit. These tests were carried out using pitot tube, digital manometer and special duct flow measurer. Experimental result was compared with the obtained simulation result. The effect of duct geometry on the velocity distribution through the grate was established through this exercise

Large-scale movement behavior in a reintroduced predator population

Understanding movement behavior and identifying areas of landscape connectivity is critical for the conservation of many species. However, collecting fine-scale movement data can be prohibitively time consuming and costly, especially for rare or endangered species, whereas existing data sets may provide the best available information on animal movement. Contemporary movement models may not be an option for modeling existing data due to low temporal resolution and large or unusual error structures, but inference can still be obtained using a functional movement modeling approach. We use a functional movement model to perform a population-level analysis of telemetry data collected during the reintroduction of Canada lynx to Colorado. Little is known about southern lynx populations compared to those in Canada and Alaska, and inference is often limited to a few individuals due to their low densities. Our analysis of a population of Canada lynx fills significant gaps in the knowledge of Canada lynx behavior at the southern edge of its historical range. We analyzed functions of individual-level movement paths, such as speed, residence time, and tortuosity, and identified a region of connectivity that extended north from the San Juan Mountains, along the continental divide, and terminated in Wyoming at the northern edge of the Southern Rocky Mountains. Individuals were able to traverse large distances across non-boreal habitat, including exploratory movements to the Greater Yellowstone area and beyond. We found evidence for an effect of seasonality and breeding status on many of the movement quantities and documented a potential reintroduction effect. Our findings provide the first analysis of Canada lynx movement in Colorado and substantially augment the information available for conservation and management decisions. Th e functional movement framework can be extended to other species and demonstrates that information on movement behavior can be obtained using existing data sets

Melvin Thomas Copeland Correspondence

Entries include a handwritten letter from Copeland on personal stationery

Contracting Out: A Study of the Honduran Experience

This study was conducted by the National Association of Schools of Public Affairs and Administration (NASPAA) at the request of USAID/Honduras under the terms of NASPAA\u27s Technical Cooperative Agreement with USAID. The study examined the experiences of USAID/Honduras and the Government of Honduras with the contracting out of construction activities in three sectors. The purpose of the study was to document empirical evidence regarding the performance of contracting out as a policy measure to increase private sector initiatives in Honduras

Toward automated irrigation management with integrated crop water stress index and spatial soil water balance

Decision support systems intended for precision irrigation aim at reducing irrigation applications while optimizing crop yield to achieve maximum crop water productivity (CWP). These systems incorporate on-site sensor data, remote sensing inputs, and advanced algorithms with spatial and temporal characteristics to compute precise crop water needs. The availability of variable rate irrigation (VRI) systems enables irrigation applications at a sub-field scale. The combination of an appropriate VRI system along with a precise decision support system would be ideal for improved CWP. The objective of this study was to compare and evaluate two decision support systems in terms of seasonal applied irrigation, crop yield, and CWP. This study implemented the Spatial EvapoTranspiration Modeling Interface (SETMI) model and the Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system for management of a center pivot irrigation system in a 58-ha maize-soybean field during the 2020 and 2021 growing seasons. The irrigation scheduling methods included: ISSCADA plant feedback, ISSCADA hybrid, common practice, and SETMI. These methods were applied at irrigation levels of 0, 50, 100, and 150% of the full irrigation prescribed by the respective irrigation scheduling method. Data from infrared thermometers (IRTs), soil water sensors, weather stations, and satellites were used in the irrigation methods. Mean seasonal irrigation prescribed was different among the irrigation levels and methods for the 2 years. The ISSCADA plant feedback prescribed the least irrigation among the methods for majority of the cases. The common practice prescribed the largest seasonal irrigation depth among the methods for three crop-year cases. The maize yield in rainfed was found to be significantly lower than the irrigated levels in 2020 since 2020 was a dry year. No significant differences were observed in crop yield among the different irrigation methods for both years. The CWP among the different irrigation methods ranged between 2.72 and 3.15 kg m−3 for 2020 maize, 1.03 and 1.13 kg m−3 for 2020 soybean, 3.57 and 4.24 kg m−3 for 2021 maize, and 1.19 and 1.48 kg m−3 for 2021 soybean. Deficit level (50%) had the largest irrigation water productivity in all crop-year cases in this study. The ISSCADA and SETMI systems were found to reduce irrigation applications as compared to the common practice while maintaining crop yield. This study was the first to implement the newly developed integrated crop water stress index (iCWSI) thresholds and the ISSCADA system for site-specific irrigation of maize and soybean in Nebraska

Toward automated irrigation management with integrated crop water stress index and spatial soil water balance

Decision support systems intended for precision irrigation aim at reducing irrigation applications while optimizing crop yield to achieve maximum crop water productivity (CWP). These systems incorporate on-site sensor data, remote sensing inputs, and advanced algorithms with spatial and temporal characteristics to compute precise crop water needs. The availability of variable rate irrigation (VRI) systems enables irrigation applications at a sub-field scale. The combination of an appropriate VRI system along with a precise decision support system would be ideal for improved CWP. The objective of this study was to compare and evaluate two decision support systems in terms of seasonal applied irrigation, crop yield, and CWP. This study implemented the Spatial EvapoTranspiration Modeling Interface (SETMI) model and the Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system for management of a center pivot irrigation system in a 58-ha maize-soybean field during the 2020 and 2021 growing seasons. The irrigation scheduling methods included: ISSCADA plant feedback, ISSCADA hybrid, common practice, and SETMI. These methods were applied at irrigation levels of 0, 50, 100, and 150% of the full irrigation prescribed by the respective irrigation scheduling method. Data from infrared thermometers (IRTs), soil water sensors, weather stations, and satellites were used in the irrigation methods. Mean seasonal irrigation prescribed was different among the irrigation levels and methods for the 2 years. The ISSCADA plant feedback prescribed the least irrigation among the methods for majority of the cases. The common practice prescribed the largest seasonal irrigation depth among the methods for three crop-year cases. The maize yield in rainfed was found to be significantly lower than the irrigated levels in 2020 since 2020 was a dry year. No significant differences were observed in crop yield among the different irrigation methods for both years. The CWP among the different irrigation methods ranged between 2.72 and 3.15 kg m−3 for 2020 maize, 1.03 and 1.13 kg m−3 for 2020 soybean, 3.57 and 4.24 kg m−3 for 2021 maize, and 1.19 and 1.48 kg m−3 for 2021 soybean. Deficit level (50%) had the largest irrigation water productivity in all crop-year cases in this study. The ISSCADA and SETMI systems were found to reduce irrigation applications as compared to the common practice while maintaining crop yield. This study was the first to implement the newly developed integrated crop water stress index (iCWSI) thresholds and the ISSCADA system for site-specific irrigation of maize and soybean in Nebraska

S-duct inlet design and experimentation for small turbojet applications: Final report, APOP Black Team

This report outlines the process of testing an S-duct inlet for a JetCat P100-RX engine that satisfies the requirements of the 2020-2021 APOP design challenge, as well as the data that accompanied this testing. Through the use of a moment arm test stand, the data for thrust could be quickly tested for. Experimental results for pressure recovery were evaluated utilizing a static pressure ring and Kiel probes for total pressure measurement. The data was then processed and reported in the form seen in this report. Although the design is likely to change, the first iteration showed promising results, with a thrust difference of 0.1% and a pressure recovery value of 99.57%. The pressure recovery can be directly compared to the CFD results that showed a pressure recovery value of about 99.8% at full rpm. In addition, the SFC value only increased by about 1% when the inlet was installed. After these results varied so little, an inlet with a smaller build volume was created to take advantage of this difference. However, the newer iteration was not able to be tested because of technical issues associated with the engine and testing equipment. It is assumed that this inlet would have produced results comparable to the CFD results, which showed a pressure recovery of 99.3%. One final iteration was completed by reducing the axial length by half an inch. The overall recovery was seen to be 99.09% in this iteration. The team saw a 0.23% frictional loss from the first iteration's experimental testing, and they do not expect that result to increase substantially; this iteration is deemed very likely to succeed. The team is satisfied with the promising recovery results, especially when compared to the small model volume. Further experimental testing is recommended as well as continued iteration