2,868 research outputs found
Escalation of error catastrophe for enzymatic self-replicators
It is a long-standing question in origin-of-life research whether the
information content of replicating molecules can be maintained in the presence
of replication errors. Extending standard quasispecies models of non-enzymatic
replication, we analyze highly specific enzymatic self-replication mediated
through an otherwise neutral recognition region, which leads to
frequency-dependent replication rates. We find a significant reduction of the
maximally tolerable error rate, because the replication rate of the fittest
molecules decreases with the fraction of functional enzymes. Our analysis is
extended to hypercyclic couplings as an example for catalytic networks.Comment: 6 pages, 4 figures; accepted at Europhys. Let
gravity, its covariant formulation, energy conservation and phase-space analysis
In the present article we analyze the matter-geometry coupled theory
of gravity. We offer the fully covariant formulation of the theory, with which
we construct the correct energy balance equation and employ it to conduct a
dynamical system analysis in a spatially flat
Friedmann-Lema\^{i}tre-Robertson-Walker spacetime. We consider three different
functional forms of the function, specifically, , , and .
We attempt to investigate the physical capabilities of these models to describe
various cosmological epochs. We calculate Friedmann-like equations in each case
and introduce some phase space variables to simplify the equations in more
concise forms. We observe that the linear model with
is completely equivalent to the GR case without cosmological constant
. Further, we find that the model with
successfully depicts the observed transition from decelerated
phase to an accelerated phase of the universe. Lastly, we find that the model
with represents an accelerated
de-Sitter epoch for the constraints or .Comment: EPJC accepted versio
Draft genome sequence of Aeromonas caviae strain L12, a quorum-sensing strain isolated from a freshwater lake in Malaysia
YesHere, we present the draft genome sequence of Aeromonas caviae strain L12, which shows quorum-sensing activity. The availability of this genome sequence is important to the research of the quorum-sensing regulatory system in this isolate.High Impact Research Grants from the University of Malaya (A000001-50001; UM-MOHE HIR Grant UM C/625/1/HIR/MOHE/CHAN/14/1, H-50001-A000027
Characterizing anomalies in distributed strain measurements of cast-in-situ bored piles
This paper describes the method of identifying typical defects of bored cast-in-situ piles when instrumenting using Distributed Optical Fiber Strain Sensing (DOFSS). The DOFSS technology is based on Brillouin Optical Time Domain Analyses (BOTDA), which has the advantage of recording continuous strain profile as opposed to the conventional discrete based sensors such as Vibrating Wire strain gauges. In pile instrumentation particularly, obtaining distributed strain profile is important when analysing the load-transfer and shaft friction of a pile, as well as detecting any anomalies in the strain regime. Features such as defective pile shaft necking, discontinuity of concrete, intrusion of foreign matter and improper toe formation due to contamination of concrete at base with soil particles, among others, may cause the pile to fail. In this study, a new technique of detecting such defects is proposed using DOFSS technology which can potentially supplement the existing non-destructive test (NDT) methods. Discussion on the performance of instrumented piles by means of maintained load test are also presented
Dr. Martin Hillenbrand to Receive University of Dayton Distinguished Alumnus Award
News release announcing the University of Dayton will Award Assistant Secretary of State for European Affairs, Dr. Martin Hillenbrand, with the Distinguished Alumnus Award
The complex relationship between empathy, engagement and boredom
In human computer interactions â especially gaming â the role of empathy has been mooted as a necessary prerequisite for higher levels of engagement and immersion. More recently other forms of engagement, including intellectual/cognitive engagement, have been proposed. In this study we present a carefully controlled dataset of human-computer interactions with a wide range of stimuli that ranged from highly engaging to boring to test these two theories. Analyzing 844 response sets to visual analogue scales (VAS) for empathy, interest, boredom, and engagement, we found that high empathy was sufficient for high engagement but is not necessary, whilst the converse was not true. We also found that empathy and boredom were incompatible with each other, but low levels of either were permissive rather than causal to the other. We conclude that there is no monotonic relationship between increasing empathy and engagement; either empathy is a sufficient (but not necessary) cause of engagement, or engagement is a necessary precursor to high empathy
Short severe energy restriction with refueling reduces body mass without altering training-associated performance improvement
Purpose
We investigated short-term (9 d) exposure to low energy availability (LEA) in elite endurance athletes during a block of intensified training on self-reported well-being, body composition, and performance.
Methods
Twenty-three highly trained race walkers undertook an ~3-wk research-embedded training camp during which they undertook baseline testing and 6 d of high energy/carbohydrate (HCHO) availability (40 kcal·kg FFMâ1·dâ1) before being allocated to 9 d continuation of this diet (n = 10 M, 2 F) or a significant decrease in energy availability to 15 kcal·kg FFMâ1·dâ1 (LEA: n = 10 M, 1 F). A real-world 10,000-m race walking event was undertaken before (baseline) and after (adaptation) these phases, with races being preceded by standardized carbohydrate fueling (8 g·kg body mass [BM]â1 for 24 h and 2 g·kg BMâ1 prerace meal).
Results
Dual-energy x-ray absorptiometryâassessed body composition showed BM loss (2.0 kg, P < 0.001), primarily due to a 1.6-kg fat mass reduction (P < 0.001) in LEA, with smaller losses (BM = 0.9 kg, P = 0.008; fat mass = 0.9 kg, P < 0.001) in HCHO. The 76-item RecoveryâStress Questionnaire for Athletes, undertaken at the end of each dietary phase, showed significant dietâtrial effects for overall stress (P = 0.021), overall recovery (P = 0.024), sport-specific stress (P = 0.003), and sport-specific recovery (P = 0.012). However, improvements in race performance were similar: 4.5% ± 4.1% and 3.5% ± 1.8% for HCHO and LEA, respectively (P < 0.001). The relationship between changes in performance and prerace BM was not significant (r = â0.08 [â0.49 to 0.35], P = 0.717).
Conclusions
A series of strategically timed but brief phases of substantially restricted energy availability might achieve ideal race weight as part of a long-term periodization of physique by high-performance athletes, but the relationship between BM, training quality, and performance in weight-dependent endurance sports is complicated
Bigger, stronger, faster, fitter : the differences in physical qualities of school and academy rugby union players
Limited research has compared the physical qualities of adolescent rugby union (RU) players across differing playing standards. This study therefore compared the physical qualities of academy and school Under-18 RU players. One-hundred and eighty-four (professional regional academy, n = 55 school, n = 129) male RU players underwent a physical testing battery to quantify height, body mass, strength (bench press and pull-up), speed (10, 20 and 40 m), 10 m momentum (calculated; 10 m velocity * body mass) and a proxy measure of aerobic fitness (Yo-Yo Intermittent Recovery Test Level 1; IRTL1). The practical significance of differences between playing levels were assessed using magnitude-based inferences. Academy players were taller (very likely small), heavier (likely moderate) and stronger (bench press possibly large; pull-up plus body mass likely small) than school players. Academy players were faster than school players over 20 and 40 m (possibly and likely small), although differences in 10 m speed were not apparent (possibly trivial). Academy players displayed greater 10 m momentum (likely moderate) and greater IRTL1 performance (likely small) than school players. These findings suggest that body size, strength, running momentum, 40 m speed and aerobic fitness contribute to a higher playing standard in adolescent rugby union
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