800 research outputs found
Ability of fitness testing to predict injury risk during initial tactical training: a systematic review and meta-analysis
Thermal Catalytic Oxidation of Airborne Contaminants by a Reactor Using Ultra-Short Channel Length, Monolithic Catalyst Substrates
Contaminated air, whether in a crewed spacecraft cabin or terrestrial work and living spaces, is a pervasive problem affecting human health, performance, and well being. The need for highly effective, economical air quality processes spans a wide range of terrestrial and space flight applications. Typically, air quality control processes rely on absorption-based processes. Most industrial packed-bed adsorption processes use activated carbon. Once saturated, the carbon is either dumped or regenerated. In either case, the dumped carbon and concentrated waste streams constitute a hazardous waste that must be handled safely while minimizing environmental impact. Thermal catalytic oxidation processes designed to address waste handling issues are moving to the forefront of cleaner air quality control and process gas decontamination processes. Careful consideration in designing the catalyst substrate and reactor can lead to more complete contaminant destruction and poisoning resistance. Maintenance improvements leading to reduced waste handling and process downtime can also be realized. Performance of a prototype thermal catalytic reaction based on ultra-short waste channel, monolith catalyst substrate design, under a variety of process flow and contaminant loading conditions, is discussed
Observation of Spontaneous Brillouin Cooling
While radiation-pressure cooling is well known, the Brillouin scattering of
light from sound is considered an acousto-optical amplification-only process.
It was suggested that cooling could be possible in multi-resonance Brillouin
systems when phonons experience lower damping than light. However, this regime
was not accessible in traditional Brillouin systems since backscattering
enforces high acoustical frequencies associated with high mechanical damping.
Recently, forward Brillouin scattering in microcavities has allowed access to
low-frequency acoustical modes where mechanical dissipation is lower than
optical dissipation, in accordance with the requirements for cooling. Here we
experimentally demonstrate cooling via such a forward Brillouin process in a
microresonator. We show two regimes of operation for the Brillouin process:
acoustical amplification as is traditional, but also for the first time, a
Brillouin cooling regime. Cooling is mediated by an optical pump, and scattered
light, that beat and electrostrictively attenuate the Brownian motion of the
mechanical mode.Comment: Supplementary material include
Heart Rate Variability Assessment of Land Navigation and Load Carriage Activities in Specialist Police Selection
Police tactical group (PTG) personnel are exposed to physical, mental, and emotional stressors. Consequently, PTG selection courses (SCs) impart similar challenges, often resulting in candidate attrition. Holistic assessment may provide additional support to stakeholders given these risks. Heart Rate Variability (HRV) is an objective holistic stress measure that may be applicable in PTG SCs but has not been thoroughly researched. Therefore, this study aimed to report HRV data in an end-user accessible format and determine the relationship between HRV and attrition. A total of 18 qualified Australian State law enforcement officers completed a 1-day physical readiness assessment. Of those, six males progressed to an additional two-day course, on which this study is focused. This two-day selection consisted of additional physical challenges and occupational assessments. HRV was obtained from 2-lead ECGs and defined as the percentage of R-R intervals that varied by ≥50 ms (pRR50). Data were summarized in a heat map of consecutive short-term analyses. Three candidates withdrew. A logistic regression based on heat map data found high HRV was significant for predicting attrition, χ2 (6) = 8.318, p = 0.004. HRV may provide insight for PTG stakeholders monitoring attrition. While the sample size was limited and replication is needed, this study tentatively establishes value for HRV monitoring in PTG SCs
Heart rate variability profile changes associated with specialist police selection activities: A case study
BACKGROUND: Police Tactical Groups (PTGs) are specialist police units tasked with rigorous physical and psychosocial duties. Consequently, selection courses (SCs) for service in these units must also be rigorous. Given the intensity of SCs, holistic monitoring for potential overstress may be beneficial. Heart Rate Variability (HRV) is one holistic stress measure that can be obtained in austere environments.OBJECTIVE: The purpose of this study was to profile HRV during a PTG SC. Six (n = 6) qualified male police officers attempted a 36-hour PTG selection course held at an Australian state facility.METHODS: HRV was obtained from Equivitaltrademark EQ02 + LifeMonitor bioharnesses. The selection course consisted of physically demanding events with minimal sleep (approx. 45 mins). Only one candidate completed the full selection course; whose results are reported here.RESULTS: A visual time-series of 384 consecutive 5 min HRV analyses was generated. Contextual analysis was applied to appreciate HRV changes between SC serials. HRV decline occurred during the planning of a navigation exercise and a pack march. Increases in HRV were observed throughout the pack march exercise and rest period.CONCLUSION: This case study demonstrates the potential utility for selection personnel to obtain additional insight into candidate responses to various occupational challenges throughout an SC. Information provided by HRV monitoring may support leadership decisions when evaluating personnel holistically. For example, the ability to continue occupational task execution even while experiencing potential overstress (as measured by HRV) and after food and sleep deprivation is desirable. HRV may potentially inform stakeholders regarding overstress in PTG candidates.</p
Ultra-short-term versus short-term measures of heart rate variability in specialist police units: A pilot reliability study
Police officers are exposed to high levels of stress. Serving on Special Weapons and Tactics (SWAT) teams is a highly demanding duty that may further increase levels of stress in police personnel. This stress may accumulate, thereby increasing allostatic load. As such, holistic stress measures may be valuable for quantifying multifactorial stress accumulation in SWAT personnel. Heart rate variability (HRV) is one field-deployable measure that may be suitable in this context. However, with logistical challenges present in this population, determining if 30 s; rather than more the typical 5-min ECG data collection, provides sufficient reliability may be beneficial for reducing the logistical barrier to adoption of HRV monitoring in SWAT personnel. This study compared 30-s to 5-min HRV analyses of ECG data obtained from 15 male SWAT personnel. Findings demonstrated good (ICC >0.8) reliability only in the VLF, HF, SD1, and SD2 HRV domains. The VLF and SD2 measures may be erroneous, as 5-min may still insufficiently characterize these measures. However, this study confirms the robust quality of nonlinear HRV analysis, as the SD1 value demonstrated the highest ICC reported here (0.902). Therefore, while 5-min ECGs may still preferable, the 30-s measure may still be viable for organizations considering HRV assessment.</p
Bridging ultrahigh-Q devices and photonic circuits
Optical microresonators are essential to a broad range of technologies and scientific disciplines. However, many of their applications rely on discrete devices to attain challenging combinations of ultra-low-loss performance (ultrahigh Q) and resonator design requirements. This prevents access to scalable fabrication methods for photonic integration and lithographic feature control. Indeed, finding a microfabrication bridge that connects ultrahigh-Q device functions with photonic circuits is a priority of the microcavity field. Here, an integrated resonator having a record Q factor over 200 million is presented. Its ultra-low-loss and flexible cavity design brings performance to integrated systems that has been the exclusive domain of discrete silica and crystalline microcavity devices. Two distinctly different devices are demonstrated: soliton sources with electronic repetition rates and high-coherence/low-threshold Brillouin lasers. This multi-device capability and performance from a single integrated cavity platform represents a critical advance for future photonic circuits and systems
Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET
Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate
Crystal Structure and Optical and Magnetic Properties of Pr2(MoO4)3
Praseodymium molybdate Pr2(MoO4)3 was synthesized using the standard ceramic route. The crystal structure of the material has been successfully solved in superspace group I2/b(Rβ0)00 with lattice constants a = 5.30284(4), b = 5.32699(3), c = 11.7935(1)A° , γ = 90.163(1) , and the modulation vector q = 2/3a*þ0.88810(2)b*. The deviation of the q vector from a rational value allows a description of the structure in terms of nanosize domains with the La2(MoO4)3-like structure separated by stacking faults. Under 450 nm excitation, (3P0 level) Pr2(MoO4)3 exhibits the characteristic red emission, with the most intense band at 649 nm corresponding to a transition. Magnetic susceptibility measurements reveal Curie-Weiss paramagnetism with predominating antiferromagnetic interactions between -magnetic moments and no evidence of magnetic transitions down to T = 5 K
Evidence of Immune Modulators in the Secretome of the Equine Tapeworm Anoplocephala perfoliata
Anoplocephala perfoliata is a neglected gastro-intestinal tapeworm, commonly infecting horses worldwide. Molecular investigation of A. perfoliata is hampered by a lack of tools to better understand the host–parasite interface. This interface is likely influenced by parasite derived immune modulators released in the secretome as free proteins or components of extracellular vesicles (EVs). Therefore, adult RNA was sequenced and de novo assembled to generate the first A. perfoliata transcriptome. In addition, excretory secretory products (ESP) from adult A. perfoliata were collected and EVs isolated using size exclusion chromatography, prior to proteomic analysis of the EVs, the EV surface and EV depleted ESP. Transcriptome analysis revealed 454 sequences homologous to known helminth immune modulators including two novel Sigma class GSTs, five α-HSP90s, and three α-enolases with isoforms of all three observed within the proteomic analysis of the secretome. Furthermore, secretome proteomics identified common helminth proteins across each sample with known EV markers, such as annexins and tetraspanins, observed in EV fractions. Importantly, 49 of the 454 putative immune modulators were identified across the secretome proteomics contained within and on the surface of EVs in addition to those identified in free ESP. This work provides the molecular tools for A. perfoliata to reveal key players in the host–parasite interaction within the horse host
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