Displacement of Tasmanian native megachilid bees by the recently introduced bumblebee Bombus terrestris (Linnaeus, 1758) (Hymenoptera : Apidae)

1999 ◽  
Vol 47 (1) ◽  
pp. 59 ◽  
Author(s):  
Peter B. McQuillan ◽  
Andrew B. Hingston
Keyword(s):  
Exotic Species ◽  
Bombus Terrestris ◽  
Limited Resource ◽  
Foraging Efficiency ◽  
Native Bees ◽  
Ambient Temperatures ◽  
The Impact

The assertion that the recently introduced large earth bumblebee, Bombus terrestris, does not compete with other bees was investigated by examining the impact of B. terrestris on the foraging of two species of Chalicodoma(Megachilidae) on flowers of Gompholobium huegelii (Fabaceae). Chalicodoma spp. spent less time at each flower during the afternoon in quadrats where B. terrestris foraged than at quadrats from which B. terrestriswas excluded, indicating that standing crops of nectar were depleted by B. terrestris during the course of the day. This decline in resources was associated with reductions in the numbers of flowers visited, and the amount of time spent foraging, by Chalicodoma spp. It is proposed that the native bees avoided foraging in the quadrat where B. terrestris occurred as a response to reduced foraging efficiency in that situation. Thus, B. terrestris displaced these two species of Chalicodoma through competition for a limited resource. The high densities at which B. terrestris occurred, together with its ability to forage at lower ambient temperatures than the native bees, exacerbated the impact of this exotic species. The possibility that this will adversely affect pollination in G. huegelii is also discussed.

scholarly journals Review: Impacts of shade on cattle well-being in the beef supply chain

2020 ◽  
Author(s):  
Lily N Edwards-Callaway ◽  
M Caitlin Cramer ◽  
Caitlin N Cadaret ◽  
Elizabeth J Bigler ◽  
Terry E Engle ◽  
...  
Keyword(s):  
Supply Chain ◽  
Heat Stress ◽  
Beef Cattle ◽  
Production Systems ◽  
Construction Materials ◽  
Well Being ◽  
Third Party ◽  
Ambient Temperatures ◽  
Stress Susceptibility ◽  
The Impact

ABSTRACT Shade is a mechanism to reduce heat load providing cattle with an environment supportive of their welfare needs. Although heat stress has been extensively reviewed, researched, and addressed in dairy production systems, it has not been investigated in the same manner in the beef cattle supply chain. Like all animals, beef cattle are susceptible to heat stress if they are unable to dissipate heat during times of elevated ambient temperatures. There are many factors that impact heat stress susceptibility in beef cattle throughout the different supply chain sectors, many of which relate to the production system, i.e. availability of shade, microclimate of environment, and nutrition management. The results from studies evaluating the effects of shade on production and welfare are difficult to compare due to variation in structural design, construction materials used, height, shape, and area of shade provided. Additionally, depending on operation location, shade may or may not be beneficial during all times of the year, which can influence the decision to make shade a permanent part of management systems. Shade has been shown to lessen the physiologic response of cattle to heat stress. Shaded cattle exhibit lower respiration rates, body temperatures, and panting scores compared to un-shaded cattle in weather that increases the risk of heat stress. Results from studies investigating the provision of shade indicate that cattle seek shade in hot weather. The impact of shade on behavioral patterns is inconsistent in the current body of research, some studies indicating shade provision impacts behavior and other studies reporting no difference between shaded and un-shaded groups. Analysis of performance and carcass characteristics across feedlot studies demonstrated that shaded cattle had increased ADG, improved feed efficiency, HCW, and dressing percentage when compared to cattle without shade. Despite the documented benefits of shade, current industry statistics, although severely limited in scope, indicate low shade implementation rates in feedlots and data in other supply chain sectors do not exist. Industry guidelines and third party on-farm certification programs articulate the critical need for protection from extreme weather but are not consistent in providing specific recommendations and requirements. Future efforts should include: updated economic analyses of cost versus benefit of shade implementation, exploration of producer perspectives and needs relative to shade, consideration of shade impacts in the cow-calf and slaughter plant segments of the supply chain, and integration of indicators of affective (mental) state and preference in research studies to enhance the holistic assessment of cattle welfare.

scholarly journals Assessment of ergot (Claviceps purpurea) exposure in pregnant and postpartum beef cows

2018 ◽  
Vol 98 (4) ◽  
pp. 688-700 ◽  
Author(s):  
T. Grusie ◽  
V. Cowan ◽  
J. Singh ◽  
J. McKinnon ◽  
B. Blakley
Keyword(s):  
Ergot Alkaloid ◽  
Post Partum ◽  
Ergot Alkaloids ◽  
Maximum Size ◽  
Beef Cows ◽  
Plasma Prolactin ◽  
Claviceps Purpurea ◽  
Ambient Temperatures ◽  
Beef Cow ◽  
The Impact

Cows were fed ration for 9 wk containing 5, 48, 201, and 822 μg kg−1 ergot alkaloids. The objective was to evaluate the impact of ergot consumption in beef cow–calf operations. Ergot alkaloids up to 822 μg kg−1 did not alter the weight of peripartum and postpartum beef cows (P = 0.93) or nursing calves (P = 0.08), rectal temperature (P = 0.16), or plasma prolactin concentrations (P = 0.30) at moderate ambient temperatures. Ergot did not influence the time (>1 ng mL−1; P = 0.79) or the progesterone concentration (P = 0.38) at the time of first postpartum rise or the size of the first (14 ± 0.6 mm; P = 0.40) and second (13 ± 0.5 mm; P = 0.41) follicles to ovulate. The maximum size of the first postpartum corpus luteum (CL) was 4 mm larger in the 822 μg kg−1 ergot group compared with the control (P = 0.03) for the first ovulation post partum, but not for the second (P = 0.11). There was no effect of ergot exposure on the number of days until the appearance of the first (43 ± 4 d; P = 0.95) or second (52 ± 4 d; P = 0.98) CL post partum. Ergot alkaloid concentrations up to 822 μg kg−1 did not affect pregnancy rates (X2 = 0.36). In conclusion, ergot alkaloid exposure for 9 wk to concentrations as high as 822 μg kg−1 did not alter performance in pregnant and postpartum beef cattle at moderate ambient temperatures.

Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus)

2001 ◽  
Vol 281 (2) ◽  
pp. R519-R527 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Alessandra Cabrera ◽  
Irving Zucker
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Ventral Surface ◽  
Phodopus Sungorus ◽  
Ambient Temperatures ◽  
Siberian Hamsters ◽  
Daily Food ◽  
Brown Adipose ◽  
Wide Range ◽  
The Impact

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters ( Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2–3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5°C) than moderate (23°C) ambient temperatures. Removal of 8 cm2 of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm2 had no effect. An 8-cm2 fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.

scholarly journals Optimization of the Return Link Carrier Planning for a Constant Coding and Modulation Satellite Network

2021 ◽  
Vol 2 ◽  
Author(s):  
C. Lacoste ◽  
N. Maturo ◽  
S. Chatzinotas ◽  
L. Emiliani
Keyword(s):  
Bandwidth Allocation ◽  
Satellite Communication ◽  
Service Providers ◽  
Limited Resource ◽  
Satellite Network ◽  
Communication Service ◽  
Implementation Costs ◽  
Core Issue ◽  
The Impact

In this paper, we propose an approach to optimize the frequency plan and associated bandwidth allocation in the return link of a broadband satellite network, by exploring several design techniques for carrier allocation plans. Since bandwidth is a limited resource in satellite telecommunications, the minimization of bandwidth usage is a core issue that satellite communication service providers must solve, in particular for networks using a constant coding and modulation plan, which lacks the flexibility found in newer satellite communication products and can be subject to hardware constraints. This problematic led us to raise the following question: how can the long term bandwidth requirement of the network be minimized, given a set of ground terminals, of Modulations and Codings, and of discrete bandwidths. In this document we formally define the long-term carrier allocation problem and analyze current practical solutions. We subsequently investigate two other potential solutions, found to be more bandwidth-efficient: one based on heuristics and another based on integer linear programming. Finally, we look at the impact of several parameters on the performance of those three methods. Overall we observed marginal reductions in bandwidth, however significant gains were reached for networks with small return links with low committed information rate, a case in which some constant coding and modulation networks could fall. We concluded that those networks could benefit from our methods and see a significant reduction in bandwidth, and subsequently operational costs, at low implementation costs.

Educational impact of a pilot paediatric simulation-based training course in Botswana

2019 ◽  
Vol 6 (5) ◽  
pp. 279-283
Author(s):  
Nicolaus W Glomb ◽  
Manish I Shah ◽  
Adeola A Kosoko ◽  
Cara B Doughty ◽  
Cafen Galapi ◽  
...  
Keyword(s):  
Test Scores ◽  
Self Efficacy ◽  
Limited Resource ◽  
Knowledge And Skills ◽  
Training Course ◽  
Resource Setting ◽  
Simulation Based ◽  
And Performance ◽  
Training Programmes ◽  
The Impact

BackgroundAs emergency medical services (EMS) systems develop globally in resource-limited settings, equipping providers with paediatric training is essential. Low-fidelity simulation-based training is an effective modality for training healthcare workers, though limited data exist on the impact of such training programmes. The objective of this study was to evaluate the paediatric portion of a simulation-based curriculum for prehospital providers in Botswana.MethodsThis was a prospective cohort study of EMS providers from more populated regions of Botswana, who attended a 2-day training that included didactic lectures, hands-on skills stations and low-fidelity simulation training. We collected data on participant self-efficacy with paediatric knowledge and skills and performance on both written and simulation-based tests. Self-efficacy and test data were analysed, and qualitative course feedback was summarised.ResultsThirty-one EMS providers participated in the training. Median self-efficacy levels increased for 13/15 (87%) variables queried. The most notable improvements were observed in airway management, newborn resuscitation and weight estimation. Mean written test scores increased by 10.6%, while mean simulation test scores increased by 21.5% (p<0.0001). One hundred per cent of the participants rated the course as extremely useful or very useful.Discussion/ConclusionWe have demonstrated that a low-fidelity simulation-based training course based on a rigorous needs assessment may enhance short-term paediatric knowledge and skills for providers in a developing EMS system in a limited-resource setting. Future studies should focus on studying larger groups of learners in similar settings, especially with respect to the impact of educational programmes like these on real-world patient outcomes.

scholarly journals Impacts of Driving Conditions on EV Battery Pack Life Cycle

2020 ◽  
Vol 11 (1) ◽  
pp. 17 ◽  
Author(s):  
Huijun Liu ◽  
Fenfang Chen ◽  
Yuxiang Tong ◽  
Zihang Wang ◽  
Xiaoli Yu ◽  
...  
Keyword(s):  
Life Cycle ◽  
Test Procedure ◽  
Lithium Ion ◽  
Driving Cycle ◽  
Battery Pack ◽  
Battery Life ◽  
Ambient Temperatures ◽  
Battery Capacity ◽  
Driving Conditions ◽  
The Impact

The aging of lithium-ion batteries (LIBs) is a crucial issue and must be investigated. The aging rate of LIBs depends not only on the material and electrochemical performance but also on the working conditions. In order to assess the impact of vehicle driving conditions, including the driving cycle, ambient temperature, charging mode, and trip distance on the battery life cycle, this paper first establishes an electric vehicle (EV) energy flow model to solve the operating parameters of the battery pack while working. Then, a powertrain test is carried out to verify the simulation model. Based on the simulated data under different conditions, the battery capacity fade process is estimated by using a semi-empirical aging model. The mileage (Ф) traveled by the vehicle before the end of life (EOL) of the battery pack is then calculated and taken as the evaluation index. The results indicate that the Ф is higher when the vehicle drives the Japanese chassis dynamometer test cycle JC08 than in the New European Driving Cycle (NEDC) and the Federal Test Procedure (FTP-75). The Ф will be dramatically reduced at both low and high ambient temperatures. Fast charging can increase the Ф at low ambient temperatures, whereas long trip driving can always increase Ф to varying degrees.

scholarly journals The effect of temperature on differentSalmonellaserotypes during warm seasons in a Mediterranean climate city, Adelaide, Australia

2015 ◽  
Vol 144 (6) ◽  
pp. 1231-1240 ◽  
Author(s):  
A. MILAZZO ◽  
L. C. GILES ◽  
Y. ZHANG ◽  
A. P. KOEHLER ◽  
J. E. HILLER ◽  
...  
Keyword(s):  
Phage Type ◽  
Warm Season ◽  
Substantial Effect ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Ambient Temperatures ◽  
Policy Interventions ◽  
Long Term Trends ◽  
Higher Temperature ◽  
The Impact

SUMMARYChanging trends in foodborne disease are influenced by many factors, including temperature. Globally and in Australia, warmer ambient temperatures are projected to rise if climate change continues.Salmonellaspp. are a temperature-sensitive pathogen and rising temperature can have a substantial effect on disease burden affecting human health. We examined the relationship between temperature andSalmonellaspp. and serotype notifications in Adelaide, Australia. Time-series Poisson regression models were fit to estimate the effect of temperature during warmer months onSalmonellaspp. and serotype cases notified from 1990 to 2012. Long-term trends, seasonality, autocorrelation and lagged effects were included in the statistical models. DailySalmonellaspp. counts increased by 1·3% [incidence rate ratio (IRR) 1·013, 95% confidence interval (CI) 1·008–1·019] per 1 °C rise in temperature in the warm season with greater increases observed in specific serotype and phage-type cases ranging from 3·4% (IRR 1·034, 95% CI 1·008–1·061) to 4·4% (IRR 1·044, 95% CI 1·024–1·064). We observed increased cases ofS. Typhimurium PT9 andS. Typhimurium PT108 notifications above a threshold of 39 °C. This study has identified the impact of warm season temperature on differentSalmonellaspp. strains and confirms higher temperature has a greater effect on phage-type notifications. The findings will contribute targeted information for public health policy interventions, including food safety programmes during warmer weather.

Canopy nectar production and the impact of logging and climate in Grey Ironbark Eucalyptus paniculata (Smith) forests

2009 ◽  
Vol 15 (4) ◽  
pp. 287 ◽  
Author(s):  
Bradley S. Law ◽  
Mark Chidel
Keyword(s):  
Feeding Activity ◽  
Negative Relationship ◽  
Limited Resource ◽  
Early Summer ◽  
Late Winter ◽  
Nectar Production ◽  
Management Actions ◽  
Logged Forest ◽  
The Impact ◽  
Regrowth Forest

Nectar in tall forest canopies is a significant, but poorly quantified, resource for Australian fauna, as well as the European Honeybee Apis mellifera. We investigated the impact of logging on nectar production in the canopy of Grey Ironbark Eucalyptus paniculata (Smith) forests in southern Australia. Using cherry-pickers and cranes we measured nectar production in large and small trees in replicate sites in each of recently logged, young regrowth and old regrowth forest over three consecutive years (2004?2006). We focused on over-night nectar production, although nectar was produced during both the day and night. Logging history and tree size, when considered individually, had no significant effect on nectar production per flower, although the two factors showed a significant interaction. However, these differences were relatively minor in comparison to the negative relationship with drought. Little nectar was produced per flower under any logging history in drought. During good conditions nectar production varied depending on logging history. When scaled up to the forest stand, logging history had a marked effect on nectar production with old regrowth forest producing seven times as much sugar per ha as recently logged forest. Young regrowth forest 15?20 years old produced nectar quantities intermediate between that of recently logged forest and regrowth forest. At the compartment scale, current practices require the retention of old forest and the typical extent of this retention reduced the difference between old regrowth forest and recently logged forest to a factor of two times. Nectar production per flower was low and a limited resource in autumn 2004 and late-winter 2005, but was copious and in surplus in early summer 2006. Nectar standing crops at the flower scale appeared to be determined by an interaction between environmental conditions (drought) that negatively influenced nectar production and the feeding activity of flower visitors at the time, which itself is affected by prevailing temperatures and nectar attributes, such as sugar concentration and regional nectar availability. We suggest that management actions should focus on minimising nectar depletion in poor flowering years when the nectar resource is limiting.

scholarly journals Was monochloramine responsible for widespread lettuce crop failures at a major recycled water irrigation scheme?

2013 ◽  
Vol 3 (2) ◽  
pp. 148-159
Author(s):  
S. F. Barker ◽  
R. Faggian ◽  
J. Blackbeard ◽  
G. Hepworth ◽  
A. J. Hamilton
Keyword(s):  
Environmental Conditions ◽  
Irrigation Water ◽  
High Salinity ◽  
Water Salinity ◽  
Recycled Water ◽  
Irrigation Scheme ◽  
Ambient Temperatures ◽  
Iceberg Lettuce ◽  
Irrigation Water Salinity ◽  
The Impact

In 2008, vegetable growers observed stunted lettuce plants showing signs of chlorosis and wilting. It was suspected that monochloramine in the recycled water used for irrigation, in combination with extreme environmental conditions (high irrigation water salinity and extreme heat), was responsible for these crop failures. A series of glasshouse studies was conducted to evaluate the impact of monochloramine concentration alone on iceberg lettuce seedlings, as well as in combination with high salinity and hot ambient temperatures. Monochloramine concentrations up to 9 and 15 mg L−1 Cl2 for continuous and initial irrigation only, respectively, did not affect the weight of iceberg lettuce heads (p &gt; 0.05), while the combination of monochloramine (4–5 mg L−1 Cl2) and salinity (3,500 μS cm−1) did not significantly affect harvest measurements (p &gt; 0.05). We therefore conclude that it is unlikely that monochloramine was responsible for the observed crop failures.

3.3 kV Rated Silicon Carbide Schottky Diodes with Epitaxial Field Stop Ring

2011 ◽  
Vol 679-680 ◽  
pp. 555-558 ◽  
Author(s):  
Konstantin Vassilevski ◽  
Irina P. Nikitina ◽  
Alton B. Horsfall ◽  
Nicolas G. Wright ◽  
C. Mark Johnson
Keyword(s):  
Silicon Carbide ◽  
Leakage Current ◽  
Schottky Diodes ◽  
Schottky Contacts ◽  
Blocking Layer ◽  
Donor Concentration ◽  
Ion Etching ◽  
Ambient Temperatures ◽  
Heavily Doped ◽  
The Impact

3.3 kV rated 4H-SiC diodes with nickel monosilicide Schottky contacts and 2-zone JTE regions were fabricated on commercial epitaxial wafers having a 34 m thick blocking layer with donor concentration of 2.2×1015 cm-3. The diodes were fabricated with and without additional field stop rings to investigate the impact of practically realizable stopper rings on the diode blocking characteristics. The field stop ring was formed by reactive ion etching of heavily doped epitaxial capping layer. The diodes with field stop rings demonstrated significantly higher yield and reduction of reverse leakage current. The diodes demonstrated blocking voltages in excess of 4.0 kV and very low change of leakage current at ambient temperatures up to 200 °C.

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