Heated aquatic microcosms for climate change experiments

Ponds and shallow lakes are likely to be strongly affected by climate change, and by increase in environmental temperature in particular. Hydrological regimes and nutrient cycling may be altered, plant and animal communities may undergo changes in both composition and dynamics, and long-term and difficult to reverse switches between alternative stable equilibria may occur. A thorough understanding of the potential effects of increased temperature on ponds and shallow lakes is desirable because these ecosystems are of immense importance throughout the world as sources of drinking water, and for their amenity and conservation value. This understanding can only come through experimental studies in which the effects of different temperature regimes are compared. This paper reports design details and operating characteristics of a recently constructed experimental facility consisting of 48 aquatic microcosms which mimic the pond and shallow lake environment. Thirty-two of the microcosms can be heated and regulated to simulate climate change scenarios, including those predicted for the UK. The authors also summarise the current and future experimental uses of the microcosms

Advanced hypersonic aircraft design

The objective of this design project is to develop the hypersonic reconnaissance aircraft to replace the SR-71 and to complement existing intelligence gathering devices. The initial design considerations were to create a manned vehicle which could complete its mission with at least two airborne refuelings. The aircraft must travel between Mach 4 and Mach 7 at an altitude of 80,000 feet for a maximum range of 12,000 nautical miles. The vehicle should have an air breathing propulsion system at cruise. With a crew of two, the aircraft should be able to take off and land on a 10,000 foot runway, and the yearly operational costs were not to exceed $300 million. Finally, the aircraft should exhibit stealth characteristics, including a minimized radar cross-section (RCS) and a reduced sonic boom. The technology used in this vehicle should allow for production between the years 1993 and 1995

THE EFFECT OF CONCUSSION ON REACTION TIME AND DUAL TASKING ABILITY IN A SIMULATED DRIVING ENVIRONMENT: SOME PRELIMINARY RESULTS

The purpose of this study was to determine the effect of concussion on drivers' reaction time and dual tasking ability in a simulated driving environment. Testing was performed with a STlSlM Model 400 driving simulator. Participants (27 healthy and 7 two weeks to six months post-concussion) were exposed to multiple reaction time scenarios including pedestrian, vehicle, and cyclist incursions. Dual tasking ability was measured using STlSlM dual task scenarios. There were longer reaction times in concussed participants (t(7.578)=2.342, p=.049) and a lower number of mean dual task passes in concussed participants (t(8.914)=2.558, p=.031), both of which were statistically significant. Understanding the effect concussion has on driving ability is the first step to creating a guideline for clinicians to refer to when assessing concussed patients and determining if they are fit to drive

Photometric Redshifts of Submillimeter Galaxies

We use the photometric redshift method of Chakrabarti & McKee (2008) to infer photometric redshifts of submillimeter galaxies with far-IR (FIR) $\it{Herschel}$ data obtained as part of the PACS Evolutionary Probe (PEP) program. For the sample with spectroscopic redshifts, we demonstrate the validity of this method over a large range of redshifts ( 4 \ga z \ga 0.3) and luminosities, finding an average accuracy in $(1+z_{\rm phot})/(1+z_{\rm spec})$ of 10%. Thus, this method is more accurate than other FIR photometric redshift methods. This method is different from typical FIR photometric methods in deriving redshifts from the light-to-gas mass ($L/M$) ratio of infrared-bright galaxies inferred from the FIR spectral energy distribution (SED), rather than dust temperatures. Once the redshift is derived, we can determine physical properties of infrared bright galaxies, including the temperature variation within the dust envelope, luminosity, mass, and surface density. We use data from the GOODS-S field to calculate the star formation rate density (SFRD) of sub-mm bright sources detected by AzTEC and PACS. The AzTEC-PACS sources, which have a threshold 850 \micron flux \ga 5 \rm mJy, contribute 15% of the SFRD from all ULIRGs (L_{\rm IR} \ga 10^{12} L_{\odot}), and 3% of the total SFRD at $z \sim 2$.Comment: 7 pages, 2 figures, submitted to Ap

Training mental imagery skills of elite athletes in virtual reality

Mental imagery practice is widely used to help athletes prepare for competitions, as it can produce motor actions that enhance performance. The goal of imagery training for athletes is to create realistic images in their minds and to familiarize them with certain procedures, environments, and other aspects related to competition. Traditional imagery training methods use still images or videos, and athletes study the pictures or watch the videos in order to mentally rehearse. However, factors such as distractions and low realism can affect the training quality. In this paper, we present a Virtual Reality (VR) solution and a study that explores our hypotheses that H1: high-fidelity VR systems improve mental imagery skills, that H2: the presence of elements such as virtual onlookers or photographers in the VR environment arouse stronger emotional reactions and affect, and that H3: the presence of elements such as onlookers or photographers in the VR environment results in better mental imagery skill improvement. For that purpose, seven elite snow sports athletes were exposed to three training methods, Video, VR-Empty, and VR-Crowded. Our results show that a VR simulation with virtual onlookers (VR-Crowded) can significantly increase heart rate, which can induce increased emotional arousal. The results from validated questionnaires show no significant difference for the three training methods in terms of mental imagery and affect, but the results show an ascending trend for the athlete’s arousal from Video to the VR-Crowded condition. Gaze detection heat maps of interest areas for the two VR conditions support hypothesis H2 that environmental factors such as the presence of photographers, staff, and onlookers can increase head and eye movement, possibly indicating an increase in emotional arousal during imagery training. According to verbal feedback and interviews, athletes are more likely to use innovative training methods (e.g., the high-fidelity VR method) than traditional video-training methods

Galaxies in a Simulated Λ\LambdaCDM Universe II: Observable Properties and Constraints on Feedback

We compare the properties of galaxies that form in a cosmological simulation without strong feedback to observations at z=0. We confirm previous findings that models without strong feedback overproduce the observed galaxy baryonic mass function, especially at the low and high mass extremes. Through post-processing we investigate what kinds of feedback would be required to reproduce observed galaxy masses and star formation rates. To mimic an extreme form of "preventive" feedback (e.g., AGN radio mode) we remove all baryonic mass that was originally accreted via "hot mode" from shock-heated gas. This does not bring the high mass end of the galaxy mass function into agreement with observations because much of the stellar mass in these systems formed at high redshift from baryons that originally accreted via "cold mode" onto lower mass progenitors. An efficient "ejective" feedback mechanism, such as supernova driven winds, must reduce the masses of these progenitors. Feedback must also reduce the masses of lower mass z=0 galaxies, which assemble at lower redshifts and have much lower star formation rates. If we monotonically re-map galaxy masses to reproduce the observed mass function, but retain the simulation's predicted star formation rates, we obtain fairly good agreement with the observed sequence of star-forming galaxies but fail to recover the observed population of passive, low star formation rate galaxies. Suppressing all hot mode accretion improves agreement for high mass galaxies but worsens the agreement at intermediate masses. Reproducing these z=0 observations requires a feedback mechanism that dramatically suppresses star formation in a fraction of galaxies, increasing with mass, while leaving star formation rates of other galaxies essentially unchanged.Comment: MNRAS in press. 15 pages, 5 figures, minimal changes from the first versio

Heated aquatic microcosms for climate change experiments

We are experiencing global climate change (e.g. Houghton et al. 1996; Huanget al. 2000). One of the main features of this change is a significant andcontinuing rise in temperature, attributable at least in part to anthropogenicenhancement of the greenhouse effect (Kerr 2000). The projected magnitudeand rapidity of this phenomenon is cause for major concern about how thebiosphere will respond

A Roadmap for HEP Software and Computing R&D for the 2020s

Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.Peer reviewe

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society