Acute Effects of Caffeine on Strength Performance in Trained and Untrained Individuals

Objective: The primary aim of this study was to compare the acute effects of a caffeine based supplement on the strength performance of trained and untrained individuals with a secondary investigation into the effects of a placebo. Method: Seven resistance trained (>6 months) and seven untrained (<6 months) males (mean ± SD: age: 21 ± 3 y, mass: 75.2 ± 11.3 kg, height: 176 ± 6 cm) consumed either caffeine (CAF) (5 mg.kg.bw-1), placebo (PLA) or nothing (CON) 60 minutes prior to 1 RM squat measurements in a double-blinded, repeated measures design. A two way repeated measures ANOVA was applied to test for the main effects of condition (CAF, PLA, CON) and group (Trained, Untrained), and the interaction effect (condition x group). Results: A significant interaction effect (F(2,11)=4.38, p=0.024) for 1 RM was observed. In the untrained group there was significant difference between CON and PLA (p<0.001). On average 1 RM in the untrained group was 12% lower in the CON trial (92.1 kg) compared to the PLA (102.9 kg; 95% CI=-5.3 to -16.1 kg), and 9% lower compared to CAF (p=0.005; 95% CI=-2.7 to 14.5 kg). There was no significant difference in 1 RM in the untrained group between PLA and CAF (p=0.87, 95% CI -3.2 to 7.5 kg). Additionally, there were no significant differences for the trained group between conditions. There was also a significant main effect for condition for 1 RM (F(2,11)=12.81, p<0.001) . Overall the CON trial was 6% lower (p=0.001, 95% CI=-3.0 to -10.6 kg) than the PLA trial (117.9 kg; 95% CI 97.6 to 124.6 kg), and 5% lower (p=0.12, 95% CI=-1.2 to -9.5 kg) than the CAF trial (116.4 kg; 95% CI 105.0 to 127.8 kg). There was no significant difference between PLA and CAF (p=0.951). Finally, there was a significant main effect for group (F(1,12)=8.79, p=0.12). On average 1 RM was 25% higher in the trained group (131.7 kg; 95% CI=114.5 to 148.9 kg) compared to the untrained group (98.6 kg; 95% CI=81.4 to 115.8 kg). Conclusion: These findings suggest that both a caffeine supplementation and placebo improve 1 RM in untrained individuals but do not improve performance in resistance trained athletes. No significant differences between caffeine and placebo, suggests placebo induced mechanisms also need to be considere

In-n-out: The Gas Cycle From Dwarfs To Spiral Galaxies

We examine the scalings of galactic outflows with halo mass across a suite of 20 high-resolution cosmological zoom galaxy simulations covering halo masses in the range 10^9.5-10^12\M. These simulations self-consistently generate outflows from the available supernova energy in a manner that successfully reproduces key galaxy observables, including the stellar mass–halo mass, Tully–Fisher, and mass–metallicity relations. We quantify the importance of ejective feedback to setting the stellar mass relative to the efficiency of gas accretion and star formation. Ejective feedback is increasingly important as galaxy mass decreases; we find an effective mass loading factor that scales as v-circ-2.2, with an amplitude and shape that are invariant with redshift. These scalings are consistent with analytic models for energy-driven wind, based solely on the halo potential. Recycling is common: about half of the outflow mass across all galaxy masses is later reaccreted. The recycling timescale is typically ~1 Gyr, virtually independent of halo mass. Recycled material is reaccreted farther out in the disk and with typically ~2–3 times more angular momentum. These results elucidate and quantify how the baryon cycle plausibly regulates star formation and alters the angular momentum distribution of disk material across the halo mass range where most cosmic star formation occurs

Fifty years of spellchecking

A short history of spellchecking from the late 1950s to the present day, describing its development through dictionary lookup, affix stripping, correction, confusion sets, and edit distance to the use of gigantic databases

Equine infectious keratitis in Finland : Associated microbial isolates and susceptibility profiles

Objective To retrospectively describe laboratory findings, treatment, and outcome associated with equine infectious keratitis in Finland. Animals and procedures Medical records of horses diagnosed with infectious keratitis in University of Helsinki Equine Hospital from January 2007 to June 2018 were reviewed. Results Forty-seven cases were included. Keratomycosis was diagnosed in 27 eyes and bacterial keratitis in 20 eyes. Aspergillus flavus was the most frequent fungal isolate (9/17, 53%), followed by Cylindrocarpon sp. (3/17, 18%) and Aspergillus fumigatus (2/17, 12%). Susceptibility was tested for 10/11 Aspergillus sp. isolates; all were susceptible to voriconazole while only two were susceptible to amphotericin B. Cylindrocarpon sp. isolates were resistant to both agents. Streptococcus equi subsp. zooepidemicus was the most frequent bacterial isolate (9/19, 47%), followed by other streptococci (4/19, 21%). All 13 Streptococcus sp. isolates were susceptible to penicillin, and all tested isolates (n = 11) were also susceptible to chloramphenicol. Mean duration of medical treatment was longer in fungal keratitis (38 days) than in bacterial keratitis (25 days) (P <.001). Twenty-six of the eyes underwent globe-sparing surgery in addition to medical therapy. Recovery was achieved in 66% (31/47) of all cases and in 59% (16/27) and 75% (15/20) (P = .264) of cases with keratomycosis and bacterial keratitis, respectively. Conclusions Although Aspergillus sp. and S zooepidemicus were the most frequently encountered isolates, cytology, culture, and susceptibility testing are essential to differentiate bacterial and fungal keratitis and guide the clinician to choose the most efficient treatment.Peer reviewe

On-shell Recursion in String Theory

We prove that all open string theory disc amplitudes in a flat background obey Britto-Cachazo-Feng-Witten (BCFW) on-shell recursion relations, up to a possible reality condition on a kinematic invariant. Arguments that the same holds for tree level closed string amplitudes are given as well. Non-adjacent BCFW-shifts are related to adjacent shifts through monodromy relations for which we provide a novel CFT based derivation. All possible recursion relations are related by old-fashioned string duality. The field theory limit of the analysis for amplitudes involving gluons is explicitly shown to be smooth for both the bosonic string as well as the superstring. In addition to a proof a less rigorous but more powerful argument based on the underlying CFT is presented which suggests that the technique may extend to a much more general setting in string theory. This is illustrated by a discussion of the open string in a constant B-field background and the closed string on the level of the sphere.Comment: 36 + 9 pages text, one figure, v3: added discussion on relation to old-fashioned factorization, typos corrected, published versio

The exoskeletons are here

It is a fantastic time for the field of robotic exoskeletons. Recent advances in actuators, sensors, materials, batteries, and computer processors have given new hope to creating the exoskeletons of yesteryear's science fiction. While the most common goal of an exoskeleton is to provide superhuman strength or endurance, scientists and engineers around the world are building exoskeletons with a wide range of diverse purposes. Exoskeletons can help patients with neurological disabilities improve their motor performance by providing task specific practice. Exoskeletons can help physiologists better understand how the human body works by providing a novel experimental perturbation. Exoskeletons can even help power mobile phones, music players, and other portable electronic devices by siphoning mechanical work performed during human locomotion. This special thematic series on robotic lower limb exoskeletons and orthoses includes eight papers presenting novel contributions to the field. The collective message of the papers is that robotic exoskeletons will contribute in many ways to the future benefit of humankind, and that future is not that distant

Correlations of behavioral deficits with brain pathology assessed through longitudinal MRI and histopathology in the R6/1 mouse model of huntington's disease

Huntington's disease (HD) is caused by the expansion of a CAG repeat in the huntingtin (HTT) gene. The R6 mouse models of HD express a mutant version of exon 1 HTT and typically develop motor and cognitive impairments, a widespread huntingtin (HTT) aggregate pathology and brain atrophy. Unlike the more commonly used R6/2 mouse line, R6/1 mice have fewer CAG repeats and, subsequently, a less rapid pathological decline. Compared to the R6/2 line, fewer descriptions of the progressive pathologies exhibited by R6/1 mice exist. The association between the molecular and cellular neuropathology with brain atrophy, and with the development of behavioral phenotypes remains poorly understood in many models of HD. In attempt to link these factors in the R6/1 mouse line, we have performed detailed assessments of behavior and of regional brain abnormalities determined through longitudinal, in vivo magnetic resonance imaging (MRI), as well as an end-stage, ex vivo MRI study and histological assessment. We found progressive decline in both motor and non-motor related behavioral tasks in R6/1 mice, first evident at 11 weeks of age. Regional brain volumes were generally unaffected at 9 weeks, but by 17 weeks there was significant grey matter atrophy. This age-related brain volume loss was validated using a more precise, semi-automated Tensor Based morphometry assessment. As well as these clear progressive phenotypes, mutant HTT (mHTT) protein, the hallmark of HD molecular pathology, was widely distributed throughout the R6/1 brain and was accompanied by neuronal loss. Despite these seemingly concomitant, robust pathological phenotypes, there appeared to be little correlation between the three main outcome measures: behavioral performance, MRI-detected brain atrophy and histopathology. In conclusion, R6/1 mice exhibit many features of HD, but the underlying mechanisms driving these clear behavioral disturbances and the brain volume loss, still remain unclear. © 2013 Rattray et al

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions.

The PHENIX collaboration presents first measurements of low-momentum (0.41  GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (&gt;5  GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield