We present the survey strategy and early results of the "Satellites Around Galactic Analogs" (SAGA) Survey. The SAGA Survey's goal is to measure the distribution of satellite galaxies around 100 ...systems analogous to the Milky Way down to the luminosity of the Leo I dwarf galaxy ( ). We define a Milky Way analog based on K-band luminosity and local environment. Here, we present satellite luminosity functions for eight Milky-Way-analog galaxies between 20 and 40 Mpc. These systems have nearly complete spectroscopic coverage of candidate satellites within the projected host virial radius down to using low-redshift gri color criteria. We have discovered a total of 25 new satellite galaxies: 14 new satellite galaxies meet our formal criteria around our complete host systems, plus 11 additional satellites in either incompletely surveyed hosts or below our formal magnitude limit. Combined with 13 previously known satellites, there are a total of 27 satellites around 8 complete Milky-Way-analog hosts. We find a wide distribution in the number of satellites per host, from 1 to 9, in the luminosity range for which there are 5 Milky Way satellites. Standard abundance matching extrapolated from higher luminosities predicts less scatter between hosts and a steeper luminosity function slope than observed. We find that the majority of satellites (26 of 27) are star-forming. These early results indicate that the Milky Way has a different satellite population than typical in our sample, potentially changing the physical interpretation of measurements based only on the Milky Way's satellite galaxies.
This study compared the postactivation potentiation (PAP) response of the hex bar deadlift (HBD) and back squat (BS) exercises. The PAP response between different levels of athletes was also ...compared. Ten professional and 10 amateur rugby league players performed 2 experimental sessions. Participants performed a countermovement jump (CMJ) before and 2, 4, 6, 8, 10, 12, 14, and 16 minutes after a conditioning activity (CA) that contained 1 set of 3 repetitions at 93% 1 repetition maximum of either HBD or BS. A force platform determined peak power output (PPO), force at PPO, velocity at PPO, and jump height of each CMJ. Surface electromyography (EMG) of the vastus lasteralis, rectus femoris, tibialis anterior, and gastrocnemius medialis of each participant's dominant leg was recorded during each CMJ. A further 10 participants performed a control trial without a CA. The HBD expressed PAP between 2 and 6 minutes post-CA, whereas the BS did not. The HBD exhibited a significantly (p ≤ 0.05) greater PAP response than the BS for PPO. There were no significant (p > 0.05) differences between stronger and weaker players. There were no significant (p > 0.05) changes in the EMG variables. These results suggest that HBD is a suitable CA for eliciting PAP in stronger and weaker athletes. Strength and conditioning coaches should consider the CA and time frame between the CA and the plyometric exercise for optimal PAP responses.
This study investigated the effect of training mode on the relationships between measures of training load in professional rugby league players.
Five measures of training load (internal: ...individualized training impulse, session rating of perceived exertion; external-body load, high-speed distance, total impacts) were collected from 17 professional male rugby league players over the course of two 12-wk preseason periods. Training was categorized by mode (small-sided games, conditioning, skills, speed, strongman, and wrestle) and subsequently subjected to a principal-component analysis. Extraction criteria were set at an eigenvalue of greater than 1. Modes that extracted more than 1 principal component were subjected to a varimax rotation.
Small-sided games and conditioning extracted 1 principal component, explaining 68% and 52% of the variance, respectively. Skills, wrestle, strongman, and speed extracted 2 principal components each explaining 68%, 71%, 72%, and 67% of the variance, respectively.
In certain training modes the inclusion of both internal and external training-load measures explained a greater proportion of the variance than any 1 individual measure. This would suggest that in training modes where 2 principal components were identified, the use of only a single internal or external training-load measure could potentially lead to an underestimation of the training dose. Consequently, a combination of internal- and external-load measures is required during certain training modes.
Personal exercise programmes have long been used and prescribed for weight loss and the improvement of quality of life in obese patients. While individualised programmes are usually the preferred ...option, they can be more costly and challenging to deliver in person. A move to digital programmes with a wider reach has commenced, and demand has increased due to the SARS-CoV-2 pandemic. In this review, we evaluate the current status of digital exercise programme delivery and its evolution over the past decade, with a focus on personalisation. We used specific keywords to search for articles that met our predetermined inclusion and exclusion criteria in order to provide valuable evidence and insights for future research. We identified 55 studies in total in four key areas of focus, from the more recent development of apps and personal digital assistants to web-based programmes and text or phone call interventions. In summary, we observed that apps may be useful for a low-intensity approach and can improve adherence to programmes through self-monitoring, but they are not always developed in an evidence-based manner. Engagement and adherence are important determinants of weight loss and subsequent weight maintenance. Generally, professional support is required to achieve weight loss goals.
Practitioners place importance on high-speed running (HSR) to monitor training practice and match-play demands, whilst attempting to maximise fitness and minimize the risk of injury occurrence. ...Practitioners apply various methods to quantify HSR, such as absolute thresholds, percentage of maximum sprint speed and maximal aerobic speed (MAS). A recent survey demonstrates the 5-minute run and 1200m shuttle test (ST) to be implemented among rugby league practitioners to quantify HSR by incorporating MAS. However, it is unclear as to how valid these methods are to accurately quantify MAS. Therefore, the aim of this study was to assess the validity of the 5-minute run and 1200m ST when compared to a gold standard measure for MAS. Twenty 1.sup.st team professional rugby league players competing in the European Super League participated in this study. Players were required to complete an incremental treadmill test, 5-minute run and 1200m ST over a two-week period in pre-season. MAS, peak heart rate (HR.sub.max ), peak lactate (La.sub.peak) and rating of perceived exertion (RPE) where collected upon completion of each test. Results demonstrated the 1200m ST to have a higher correlation for MAS than the 5-minute run (1200m ST: r = 0.73, 5-minute run: r = 0.64). However, when assessing validity using the level of agreement between data, the 5-minute run underreported MAS by 0.45 m·s.sup.-1 whereas the 1200m ST underreported MAS by 0.77 m·s.sup.-1 . Ultimately, both field-based tests used in this study underreport MAS when compared to an incremental treadmill test, although the 5-minute run provides a closer agreement and therefore a more valid measurement for MAS than the 1200m ST.
The galaxy cluster 1ES 0657-558 (z = 0.296) is remarkably well suited for addressing outstanding issues in both galaxy evolution and fundamental physics. We present a reconstruction of the mass ...distribution from both strong and weak gravitational lensing data. Multicolor, high-resolution HST ACS images allow detection of many more arc candidates than were previously known, especially around the subcluster. Using the known redshift of one of the multiply imaged systems, we determine the remaining source redshifts using the predictive power of the strong-lens model. Combining this information with shape measurements of "weakly" lensed sources, we derive a high-resolution, absolutely calibrated mass map, using no assumptions regarding the physical properties of the underlying cluster potential. This map provides the best available quantification of the total mass of the central part of the cluster. We also confirm the result from Clowe and colleagues that the total mass does not trace the baryonic mass.
An atlas of predicted exotic gravitational lenses Orban de Xivry, Gilles; Marshall, Phil
Monthly Notices of the Royal Astronomical Society,
10/2009, Letnik:
399, Številka:
1
Journal Article, Web Resource
Recenzirano
Odprti dostop
Wide-field optical imaging surveys will contain tens of thousands of new strong gravitational lenses. Some of these will have new and unusual image configurations, and so will enable new ...applications: for example, systems with high image multiplicity will allow more detailed study of galaxy and group mass distributions, while high magnification is needed to super-resolve the faintest objects in the high-redshift universe. Inspired by a set of six unusual lens systems including five selected from the Sloan Lens ACS survey (SLACS) and Strong Lens Legacy Survey (SL2S), plus the cluster Abell 1703, we consider several types of multi-component, physically motivated lens potentials, and use the ray-tracing code glamroc to predict exotic image configurations. We also investigate the effects of galaxy source profile and size, and use realistic sources to predict observable magnifications and estimate very approximate relative cross-sections. We find that lens galaxies with misaligned discs and bulges produce swallowtail and butterfly catastrophes, observable as ‘broken’ Einstein rings. Binary or merging galaxies show elliptic umbilic catastrophes, leading to an unusual Y-shaped configuration of four merging images. While not the maximum magnification configuration possible, it offers the possibility of mapping the local small-scale mass distribution. We estimate the approximate abundance of each of these exotic galaxy-scale lenses to be ∼1 per all-sky survey. In higher mass systems, a wide range of caustic structures are expected, as already seen in many cluster lens systems. We interpret the central ring and its counter-image in Abell 1703 as a ‘hyperbolic umbilic’ configuration, with total magnification ∼100 (depending on source size). The abundance of such configurations is also estimated to be ∼1 per all-sky survey.
Abstract Wearable GPS tracking devices have become commonplace coaching aids across professional field sports to enhance sports performances and reduce injury rates, despite the implications of the ...technology being poorly understood. This study looked at how GPS devices are used and the impact constant surveillance has upon the physical, psychological, and emotional health of rugby football workers. The disciplinary analysis of Michel Foucault was used to investigate how British Super League teams use wearable GPS technology, to investigate the dominant 'truth' that promotes surveillance technologies as 'universally beneficial' to athlete sports performance, health and well-being. Data was drawn from semi-structured interviews with three performance analysts/strength and conditioning coaches at three different Super League clubs across the North of England. Participants confessed data generated from wearable GPS is often totally ignored, despite being specifically produced to protect athlete health and wellbeing. When used, GPS data can become a 'disciplinary tool' to normalise and coerce players to comply with potentially unhealthy physical and psychological demands of a professional playing career. Importantly, regardless of how GPS data was used, the employment of wearable GPS devices was constantly and rigorously implemented. The constant surveillance experience by working players, when mismanaged or adopted as a coercive disciplinary tool, magnifies the uncertainty and fear of failure central to the predominant challenges that arise during a working football career. This leads to the acceptance of problematic norms damaging to physical, psychological, and emotional health. If GPS or other surveillance based performance analysis technologies are to be used in sport, coaches need to regulate or re-think their day-to-day use to avoid creating new harms to athlete health and well-being.
The Enhanced Recovery after Surgery (ERAS) model integrates several elements of perioperative care into a standardised clinical pathway for surgical patients. ERAS programmes aim to reduce the rate ...of complications, improve surgical recovery, and limit postoperative length of hospital stay (LOHS). One area of growing interest that is not currently included within ERAS protocols is the use of exercise prehabilitation (PREHAB) interventions. PREHAB refers to the systematic process of improving functional capacity of the patient to withstand the upcoming physiological stress of surgery. A number of recent systematic reviews have examined the role of PREHAB prior to elective intra-cavity surgery. However, the results have been conflicting and a definitive conclusion has not been obtained. Furthermore, a summary of the research area focussing exclusively on the therapeutic potential of exercise prior to intra-cavity surgery is yet to be undertaken. Clarification is required to better inform perioperative care and advance the research field. Therefore, this “review of reviews” provides a critical overview of currently available evidence on the effect of exercise PREHAB in patients undergoing i) coronary artery bypass graft surgery (CABG), ii) lung resection surgery, and iii) gastrointestinal and colorectal surgery. We discuss the findings of systematic reviews and meta-analyses and supplement these with recently published clinical trials. This article summarises the research findings and identifies pertinent gaps in the research area that warrant further investigation. Finally, studies are conceptually synthesised to discuss the feasibility of PREHAB in clinical practice and its potential role within the ERAS pathway.
•Prehabilitation appears to be effective for improving physical fitness prior to surgery.•Changes in physical fitness may not translate into improved perioperative outcomes.•The literature is dominated by small RCTs and single-group observational trials.•Most prehabilitation interventions involve generic prescriptions of aerobic exercise.
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