Ariel - Volume 11 Number 3

Executive Editors Ellen Feldman Leonardo S. Nasca, Jr. Business Managers Barbara L. Davies Martin B. Getzow News Editor Hugh A. Gelabert Features Editor Aaron D. Bleznak CAHS Editor Joan M. Greco Editorial Page Editor Samuel Markind Photography Editor Todd Demmy Sports Editor Paul F. Mansfiel

Effects of Prior Fasting on Fat Oxidation during Resistance Exercise

International Journal of Exercise Science 11(2): 827-833, 2018. Prior research has demonstrated that the percentage of fuel utilization contributed by CHO compared to fat rises with an increase in exercise intensity. The role of food intake prior to exercise has been well studied and fasting prior to exercise generally increases reliance on fat as fuel. However, data on the role of fasting prior to resistance exercise is limited. Therefore, the purpose of this study was to assess the effects of one bout of resistance training in a fasted state compared to ingestion of standardized meal on fat and carbohydrate utilization. Twelve female (n = 12, age = 20.1 ± 0.79 yrs, height = 67.0 ± 2.63 in, weight = 143 ± 21.8 lbs) NCAA Division 1 athletes participated in the study. Each participant completed one 10 hour fasted resistance training session and one postprandial resistance training session. The respiratory exchange ratio (RER) and METs were measured using a Cosmed K4b2portable metabolic cart (Cosmed, Rome, Italy) and heart rate was measured by a Polar H1 heart rate monitor. Participants consumed the prescribed food, waited 15 minutes, and then completed three sets of five repetitions of bench press, back squat, and military press at 60% of their 1-repetition maximum. The mean fasted RER was significantly lower than postprandial for back squat (p=0.01) and military press (p=0.02), but not bench press (p=0.19). There was no difference in METs, RPE, or HR between fasted and postprandial trials for any exercise. Results suggest that fasted resistance exercise relies more heavily on fat metabolism than carbohydrate

Evaluating ad hoc routing protocols with respect to quality of service

2005 IEEE International Conference on Wireless and Mobile Computing, Networking and Communications, WiMob'2005, Aug 22-24 2005, 3: pp. 205-212.The ability of a Mobile Ad Hoc Network (MANET) to provide adequate quality of service (QoS) is limited by the ability of the underlying routing protocol to provide consistent behavior despite the inherent dynamics of a mobile computing environment. In this paper we study three MANET routing protocols: OLSR, DSR and AODV, with an emphasis on the effect they have on various QoS metrics. We describe and analyze how the protocols differ in the mechanisms they use to select paths, detect broken links, and buffer messages during periods of link outage. The effects of these differences are quantified in terms of packet delivery ratio, end-to-end hop count, endto- end latency, and mechanism overhead. We show that the proactive protocol, OLSR, builds paths with consistently lower hop counts than the reactive protocols, AODV and DSR, a fact that leads to a reduction in end-to-end latency that assists a QoS model in meeting timing requirements and improves global network performance. We further show the impact of broken link detection latency on the packet delivery ratio. A routing protocol that can not quickly recover from link breakage caused by mobility renders a QoS model incapable of meeting delivery requirements. Finally, we analyze the effect of mobility on the distribution of end-to-end latencies. Traditionally, reactive protocols are criticized for buffering during the building of routes, however we also study buffering phenomenon caused by the proactive mechanisms of OLSR

Safety and Performance in an Open Packet Monitoring Architecture

Packet monitoring arguably needs the flexibility of open architectures and active networking. A significant challenge in the design of open packet monitoring systems is how to effectively strike a balance between flexibility, safety and performance. In this paper we investigate the performance of FLAME, a system that emphasizes flexibility by allowing applications to execute arbitrary code for each packet received. Our system attempts to achieve high performance without sacrificing safety by combining the use of a type-safe language, lightweight run-time checks, and fine-grained policy restrictions. Experiments with our prototype implementation demonstrate the ability of our system to support representative application workloads on Bgit/s links. Such performance indicates the overall efficiency of our approach; more narrowly targeted experiments demonstrate that the overhead required to provide safety is acceptable

Improved profile fitting and quantification of uncertainty in experimental measurements of impurity transport coefficients using Gaussian process regression

The need to fit smooth temperature and density profiles to discrete observations is ubiquitous in plasma physics, but the prevailing techniques for this have many shortcomings that cast doubt on the statistical validity of the results. This issue is amplified in the context of validation of gyrokinetic transport models (Holland et al 2009 Phys. Plasmas 16 052301), where the strong sensitivity of the code outputs to input gradients means that inadequacies in the profile fitting technique can easily lead to an incorrect assessment of the degree of agreement with experimental measurements. In order to rectify the shortcomings of standard approaches to profile fitting, we have applied Gaussian process regression (GPR), a powerful non-parametric regression technique, to analyse an Alcator C-Mod L-mode discharge used for past gyrokinetic validation work (Howard et al 2012 Nucl. Fusion 52 063002). We show that the GPR techniques can reproduce the previous results while delivering more statistically rigorous fits and uncertainty estimates for both the value and the gradient of plasma profiles with an improved level of automation. We also discuss how the use of GPR can allow for dramatic increases in the rate of convergence of uncertainty propagation for any code that takes experimental profiles as inputs. The new GPR techniques for profile fitting and uncertainty propagation are quite useful and general, and we describe the steps to implementation in detail in this paper. These techniques have the potential to substantially improve the quality of uncertainty estimates on profile fits and the rate of convergence of uncertainty propagation, making them of great interest for wider use in fusion experiments and modelling efforts.United States. Dept. of Energy. Office of Fusion Energy Sciences (Award DE-FC02-99ER54512)United States. Dept. of Energy. Office of Science (Contract DE-AC05-06OR23177)United States. Dept. of Energy. Office of Advanced Scientific Computing Research (Award DE-SC0007099

Experimental Aerosol Inoculation and Investigation of Potential Lateral Transmission of Mycobacterium bovis in Virginia Opossum (Didelphis virginiana)

An endemic focus of Mycobacterium bovis (M. bovis) infection in the state of Michigan has contributed to a regional persistence in the animal population. The objective of this study was to determine if Virginia opossums (Didelphis virginiana) contribute to disease persistence by experimentally assessing intraspecies lateral transmission. One wild caught pregnant female opossum bearing 11 joeys (young opossum) and one age-matched joey were obtained for the study. Four joeys were aerosol inoculated with M. bovis (inoculated), four joeys were noninoculated (exposed), and four joeys plus the dam were controls. Four replicate groups of one inoculated and one exposed joey were housed together for 45 days commencing 7 days after experimental inoculation. At day 84 opossums were sacrificed. All four inoculated opossums had a positive test band via rapid test, culture positive, and gross/histologic lesions consistent with caseogranulomatous pneumonia. The exposed and control groups were unremarkable on gross, histology, rapid test, and culture. In conclusion, M. bovis infection within the inoculated opossums was confirmed by gross pathology, histopathology, bacterial culture, and antibody tests. However, M. bovis was not detected in the control and exposed opossums. There was no appreciable lateral transmission of M. bovis after aerosol inoculation and 45 days of cohabitation between infected and uninfected opossums

Hyporheic Exchange and Water Chemistry of Two Arctic Tundra Streams of Contrasting Geomorphology

The North Slope of Alaska’s Brooks Range is underlain by continuous permafrost, but an active layer of thawed sediments develops at the tundra surface and beneath streambeds during the summer, facilitating hyporheic exchange. Our goal was to understand how active layer extent and stream geomorphology influence hyporheic exchange and nutrient chemistry. We studied two arctic tundra streams of contrasting geomorphology: a high-gradient, alluvial stream with riffle-pool sequences and a low-gradient, peat-bottomed stream with large deep pools connected by deep runs. Hyporheic exchange occurred to ~50 cm beneath the alluvial streambed and to only ~15 cm beneath the peat streambed. The thaw bulb was deeper than the hyporheic exchange zone in both stream types. The hyporheic zone was a net source of ammonium and soluble reactive phosphorus in both stream types. The hyporheic zone was a net source of nitrate in the alluvial stream, but a net nitrate sink in the peat stream. The mass flux of nutrients regenerated from the hyporheic zones in these two streams was a small portion of the surface water mass flux. Although small, hyporheic sources of regenerated nutrients help maintain the in-stream nutrient balance. If future warming in the arctic increases the depth of the thaw bulb, it may not increase the vertical extent of hyporheic exchange. The greater impacts on annual contributions of hyporheic regeneration are likely to be due to longer thawed seasons, increased sediment temperatures or changes in geomorphology

Influence of Morphology and Permafrost Dynamics on Hyporheic Exchange in Arctic Headwater Streams under Warming Climate Conditions

We investigated surface-subsurface (hyporheic) exchange in two morphologically distinct arctic headwater streams experiencing warming (thawing) sub-channel conditions. Empirically parameterized and calibrated groundwater flow models were used to assess the influence of sub-channel thaw on hyporheic exchange. Average thaw depths were at least two-fold greater under the higher-energy, alluvial stream than under the lowenergy, peat-lined stream. Alluvial hyporheic exchange had shorter residence times and longer flowpaths that occurred across greater portions of the thawed sediments. For both reaches, the morphologic (longitudinal bed topography) and hydraulic conditions (surface and groundwater flow properties) set the potential for hyporheic flow. Simulations of deeper thaw, as predicted under a warming arctic climate, only influence hyporheic exchange until a threshold depth. This depth is primarily determined by the hydraulic head gradients imposed by the stream morphology. Therefore, arctic hyporheic exchange extent is likely to be independent of greater sub-stream thaw depths

Multiradar observations of the polar tongue of ionization

[1] We present a global view of large‐scale ionospheric disturbances during the main phase of a major geomagnetic storm. We find that the low‐latitude, auroral, and polar latitude regions are coupled by processes that redistribute thermal plasma throughout the system. For the large geomagnetic storm on 20 November 2003, we examine data from the high‐latitude incoherent scatter radars at Millstone Hill, Sondrestrom, and EISCAT Tromso, with SuperDARN HF radar observations of the high‐latitude convection pattern and DMSP observations of in situ plasma parameters in the topside ionosphere. We combine these with north polar maps of stormtime plumes of enhanced total electron content (TEC) derived from a network of GPS receivers. The polar tongue of ionization (TOI) is seen to be a continuous stream of dense cold plasma entrained in the global convection pattern. The dayside source of the TOI is the plume of storm enhanced density (SED) transported from low latitudes in the postnoon sector by the subauroral disturbance electric field. Convection carries this material through the dayside cusp and across the polar cap to the nightside where the auroral F region is significantly enhanced by the SED material. The three incoherent scatter radars provided full altitude profiles of plasma density, temperatures, and vertical velocity as the TOI plume crossed their different positions, under the cusp, in the center of the polar cap, and at the midnight oval/polar cap boundary. Greatly elevated F peak density (>1.5E12 m[superscript −3]) and low electron and ion temperatures (∼2500 K at the F peak altitude) characterize the SED/TOI plasma observed at all points along its high‐latitude trajectory. For this event, SED/TOI F region TEC (150–1000 km) was ∼50 TECu both in the cusp and in the center of the polar cap. Large, upward directed fluxes of O+ (>1.E14 m[superscript −2] s[superscript −1]) were observed in the topside ionosphere from the SED/TOI plume within the cusp