629 research outputs found
AUTONOMOUS MANEUVERING: A DEFENSE ADVANTAGE FOR AFSOC AIRCRAFT
The U.S. military continues to operate in increasingly complex security environments and can no longer expect uncontested or dominant superiority in every domain. Aircraft operated by special operations forces (SOF) need improved defensive capabilities to support missions in non-permissive environments. Integrating automation and human-machine teaming into existing defensive capabilities may reduce threat reaction time and increase the effectiveness of defensive maneuvers in manned and unmanned aircraft configurations. This thesis examines the value of aircraft maneuvering as part of a threat reaction to identify situations where human intervention negatively affects timing and accuracy. It also considers opportunities to replicate Merlin Labs' approach to flight automation and incorporate a machine-trained system capable of performing defensive maneuvers into existing aircraft. The analysis indicates aircraft maneuvering is critical to an effective threat reaction, and automating select operator actions can increase survivability against certain surface-to-air threats. This thesis recommends a renewed focus on defensive capabilities for SOF aircraft and endorses integrating onboard autonomous systems into traditionally manned platforms to improve defensive threat reactions. It also advocates for continued research into the use of optionally manned aircraft in SOF missions to refine their operational utility and expand capabilities across a variety of mission platforms.Major, United States Air ForceMajor, United States Air ForceApproved for public release. Distribution is unlimited
Protein hydrolysates and recovery of muscle damage following eccentric exercise
Background: A whey protein hydrolysate (NatraBoost XR; WPHNB) has been shown to speed repair muscle damage. We sought to determine whether this benefit is specific to this hydrolysate to evaluate a marker for quality control. Methods: Three hydrolysates of the same whey protein isolate (WPI) were prepared (WPHNB, WPH1 and WPH2). Isometric knee extensor strength was measured in 39 sedentary male participants before and after 100 maximal eccentric contractions of the knee extensors to induce muscle damage. Participants were then randomised to consume 250 ml of flavoured water (FW, n=9), or 250 ml of FW containing 25 g of either NatraBoost XR (n=3), WPH1 (n=9), WPH2 (n=9) or WPI (n=9). Strength was reassessed over the next seven days while the supplements were consumed daily. Fibroblasts were cultured for 48 hr in the presence of the different hydrolysates, WPI, saline or fetal bovine serum to ascertain effects on cell proliferation. Results: Strength was reduced in all treatment groups after eccentric exercise (P<0.001). Strength recovered steadily over 7 days in the FW, WPI, WPH1 and WPH2 treatment groups (P<0.001), with no difference between treatments (P=0.87). WPHNB promoted faster strength recovery compared with the other treatments (P<0.001). Fibroblast proliferation was greater with WPHNB compared with saline, WPI or the other hydrolysates (P<0.001). Conclusions: Promoting recovery from muscle damage seems unique to WPHNB. In vitro fibroblast proliferation may be a useful marker for quality control. It is not clear whether effects on fibroblast proliferation contribute to the in vivo effect of WPHNB on muscle damage
Recommended from our members
Is a depth camera in agreement with an electromagnetic tracking device when measuring head position?
Introduction: Clinicians typically observe and describe abnormal head postures (AHPs) and may also measure them. Depth cameras have been suggested as a reliable measurement device for measuring head position using face-tracking technology. This study compared a depth camera (Microsoft Kinect) to a gold standard electromagnetic tracking system (Polhemus device) to measure head position. Method: Twenty healthy volunteers (mean age 21 years) had their head position simultaneously recorded using the depth camera (Kinect) and the electromagnetic tracking system (Polhemus). Participants were asked to make 30-degree head movements into chin up, chin down, head turn and head tilt positions. The head movement made and the stability of the head at each position were recorded and analysed. Results: Compared to the electromagnetic tracking system (Polhemus), the depth camera (Kinect) always measured a smaller head movement. Measurements with the two devices were not statistically significantly different for turn right (P = 0.3955, p > 0.05), turn left (P = 0.4749, p > 0.05), tilt right (P = 0.7086, p > 0.05) and tilt left (P = 0.4091, p > 0.05) head movements. However, the smaller depth camera measurement of chin up and chin down head movements were statistically significant, chin up (P = 0.0001, p < 0.01) and chin down (P = 0.0005, p < 0.001). At each eccentric position, the depth camera (Kinect) recordings were more variable than the electromagnetic tracking system (Polhemus). Conclusions: Compared to the electromagnetic tracking system (Polhemus), the depth camera (Kinect) was comparable for measuring head turns and tilts but was less accurate at measuring chin up and chin down head positions. Further research is needed before the depth cameras are considered for clinical recordings of head position
Effects of eating fresh lean pork on cardiometabolic health parameters
High protein meat-based diets are commonly promoted for weight loss, supposedly by increasing satiety and energy expenditure. Pork is a good source of protein however little information on the metabolic effects of pork consumption exists. This pilot study aimed to examine whether regular consumption of fresh lean pork could improve body composition and cardiovascular risk factors in a 6 month parallel intervention trial. 164 overweight adults (mean BMI 32) were randomly assigned to incorporate up to 1 kg pork/week by substituting for other foods or maintain their habitual diet (control). Plasma levels of lipids, glucose and insulin, BMI, waist/hip circumference, blood pressure, heart rate and arterial compliance were measured at baseline and 3 and 6 months. Body composition was determined using dual energy X-ray absorptiometry. A total of 144 volunteers completed and volunteers in the pork group increased their intake 10 fold by substituting pork for mainly beef and chicken. After 3 months, there were significant (p ≤ 0.01) reductions in weight, BMI, waist circumference, % body fat, fat mass and abdominal fat in the pork group relative to controls, which persisted for 6 months. There was no change in lean mass, indicating that the reduction in weight was due to loss of fat mass. There were no significant effects on other metabolic parameters. Regular consumption of lean fresh pork may improve body composition
Relationships between Obesity, Cardiorespiratory Fitness, and Cardiovascular Function
Background. Obesity and low cardiorespiratory fitness (CRF) have been shown to independently increase the risk of CVD mortality. The aim of this study was to investigate the relationship between CRF, body fatness and markers of arterial function. Method and Results. Obese (9 male, 18 female; BMI 35.3 ± 0.9 kg·m−2) and lean (8 male, 18 female; BMI 22.5 ± 0.3 kg·m−2) volunteers were assessed for body composition (DXA), cardiorespiratory fitness (predicted V˙O2max), blood pressure (BP), endothelial vasodilatator function (FMD), and arterial compliance (AC) (via radial artery tonometry). The obese group had more whole body fat and abdominal fat (43.5 ± 1.2% versus 27.2 ± 1.6%; P < .001 and 48.6 ± 0.9% versus 28.9 ± 1.8%; P < .001, resp.), and lower FMD (3.2 ± 0.4% versus 5.7 ± 0.7%; P < .01) than the lean subjects, but there was no difference in AC. AC in large arteries was positively associated with CRF (R = 0.5; P < .01) but not with fatness. Conclusion. These results indicate distinct influences of obesity and CRF on blood vessel health. FMD was impaired with obesity, which may contribute to arterial and metabolic dysfunction. Low CRF was associated with reduced elasticity in large arteries, which could result in augmentation of aortic afterload
Reversible Optogenetic Control of Subcellular Protein Localization in a Live Vertebrate Embryo.
We demonstrate the utility of the phytochrome system to rapidly and reversibly recruit proteins to specific subcellular regions within specific cells in a living vertebrate embryo. Light-induced heterodimerization using the phytochrome system has previously been used as a powerful tool to dissect signaling pathways for single cells in culture but has not previously been used to reversibly manipulate the precise subcellular location of proteins in multicellular organisms. Here we report the experimental conditions necessary to use this system to manipulate proteins in vivo. As proof of principle, we demonstrate that we can manipulate the localization of the apical polarity protein Pard3 with high temporal and spatial precision in both the neural tube and the embryo's enveloping layer epithelium. Our optimizations of optogenetic component expression and chromophore purification and delivery should significantly lower the barrier for establishing this powerful optogenetic system in other multicellular organisms
Time-dependence in Relativistic Collisionless Shocks: Theory of the Variable "Wisps" in the Crab Nebula
We describe results from time-dependent numerical modeling of the
collisionless reverse shock terminating the pulsar wind in the Crab Nebula. We
treat the upstream relativistic wind as composed of ions and electron-positron
plasma embedded in a toroidal magnetic field, flowing radially outward from the
pulsar in a sector around the rotational equator. The relativistic cyclotron
instability of the ion gyrational orbit downstream of the leading shock in the
electron-positron pairs launches outward propagating magnetosonic waves.
Because of the fresh supply of ions crossing the shock, this time-dependent
process achieves a limit-cycle, in which the waves are launched with
periodicity on the order of the ion Larmor time. Compressions in the magnetic
field and pair density associated with these waves, as well as their
propagation speed, semi-quantitatively reproduce the behavior of the wisp and
ring features described in recent observations obtained using the Hubble Space
Telescope and the Chandra X-Ray Observatory. By selecting the parameters of the
ion orbits to fit the spatial separation of the wisps, we predict the period of
time variability of the wisps that is consistent with the data. When coupled
with a mechanism for non-thermal acceleration of the pairs, the compressions in
the magnetic field and plasma density associated with the optical wisp
structure naturally account for the location of X-ray features in the Crab. We
also discuss the origin of the high energy ions and their acceleration in the
equatorial current sheet of the pulsar wind.Comment: 13 pages, 4 figures, accepted to ApJ. High-resolution figures and
mpeg movies available at http://astron.berkeley.edu/~anatoly/wisp
Recommended from our members
Homoepitaxial Growth of Single Crystal Diamond Membranes for Quantum Information Processing
Fabrication of devices designed to fully harness the unique properties of quantum mechanics through their coupling to quantum bits (qubits) is a prominent goal in the field of quantum information processing (QIP). Among various qubit candidates, nitrogen vacancy (NV) centers in diamond have recently emerged as an outstanding platform for room temperature QIP. However, formidable challenges still remain in processing diamond and in the fabrication of thin diamond membranes, which are necessary for planar photonic device engineering. Here we demonstrate epitaxial growth of single crystal diamond membranes using a conventional microwave chemical vapor deposition (CVD) technique. The grown membranes, only a few hundred nanometers thick, show bright luminescence, excellent Raman signature and good NV center electronic spin coherence times. Microdisk cavities fabricated from these membranes exhibit quality factors of up to 3000, overlapping with NV center emission. Our methodology offers a scalable approach for diamond device fabrication for photonics, spintronics, optomechanics and sensing applications.Engineering and Applied Science
A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running
Background Treadmills are routinely used to assess running performance and training parameters related to physiological or perceived effort. These measurements are presumed to replicate overground running but there has been no systematic review comparing performance, physiology and perceived effort between treadmill and overground running. Objective The objective of this systematic review was to compare physiological, perceptual and performance measures between treadmill and overground running in healthy adults.MethodsAMED (Allied and Contemporary Medicine), CINAHL (Cumulative Index to Nursing and Allied Health), EMBASE, MEDLINE, SCOPUS, SPORTDiscus and Web of Science databases were searched from inception until May 2018. Included studies used a crossover study design to compare physiological (oxygen uptake [VO-2], heart rate [HR], blood lactate concentration [La]), perceptual (rating of perceived exertion [RPE] and preferred speed) or running endurance and sprint performance (i.e. time trial duration or sprint speed) outcomes between treadmill (motorised or non-motorised) and overground running. Physiological outcomes were considered across submaximal, near-maximal and maximal running intensity subgroups. Meta-analyses were used to determine mean difference (MD) or standardised MD (SMD) 95% confidence intervals. Results Thirty-four studies were included. Twelve studies used a 1% grade for the treadmill condition and three used grades >1%. Similar (V) over dotO(2) but lower La occurred during submaximal motorised treadmill running at 0% ((V) over dot O-2 MD: -0.55 0.93mL/kg/min; La MD: -1.26 +/- 0.71mmol/L) and 1% ((V) over dotO(2) MD: 0.37 +/- 1.12mL/kg/min; La MD: -0.52 +/- 0.50mmol/L) grade than during overground running. HR and RPE during motorised treadmill running were higher at faster submaximal speeds and lower at slower submaximal speeds than during overground running. (V) over dotO(2) (MD: -1.25 +/- 2.09mL/kg/min) and La (MD: -0.54 +/- 0.63mmol/L) tended to be lower, but HR (MD: 0 +/- 1bpm), and RPE (MD: -0.4 +/- 2.0units [6-20 scale]) were similar during near-maximal motorised treadmill running to during overground running. Maximal motorised treadmill running caused similar (V) over dotO(2) (MD: 0.78 +/- 1.55mL/kg/min) and HR (MD: -1 +/- 2bpm) to overground running. Endurance performance was poorer (SMD: -0.50 +/- 0.36) on a motorised treadmill than overground but sprint performance varied considerably and was not significantly different (MD: -1.4 +/- 5.8km/h). Conclusions Some, but not all, variables differ between treadmill and overground running, and may be dependent on the running speed at which they are assessed. Protocol registration (PROSPERO International Prospective Register of Systematic Reviews)
- …