Diagonal Slice Four-Wave Mixing: Natural Separation of Coherent Broadening Mechanisms

We present an ultrafast coherent spectroscopy data acquisition scheme that samples slices of the time domain used in multidimensional coherent spectroscopy to achieve faster data collection than full spectra. We derive analytical expressions for resonance lineshapes using this technique that completely separate homogeneous and inhomogeneous broadening contributions into separate projected lineshapes for arbitrary inhomogeneous broadening. These lineshape expressions are also valid for slices taken from full multidimensional spectra and allow direct measurement of the parameters contributing to the lineshapes in those spectra as well as our own

The Effects on Acute Power Production Enhancement and Maintenance due to Pre-workout Supplementation in Recreationally trained College Aged Males.

Introduction: The current research in power production has shown the use of pre-workout supplements to increase peak power production, but the current research has not yet been able to delve in to the effectiveness of pre-workout supplementation on maintaining power production. Purpose: The purpose of this study was to examine the effects on acute power production enhancement and maintenance due to supplementation in recreationally trained college aged individuals. Methods: Data was collected from 13 recreationally trained, college-aged males in a double-blind crossover study. After a familiarization sessions subjects participated in three testing sessions utilizing a cross over double blind design (Supplement, Placebo+Caffeine and Placebo). Subjects arrived and ingested their beverage and after waiting 20 minutes performed a warm up and then vertical jump testing (5 jumps). Subjects then performed ten bike sprints utilizing a Monark ergo bike, with each subject’s resistance being 7.5% of their body weight in kg. Each sprint last 5 seconds with a 55 second recovery. Subjects then performed another round of vertical jumps utilizing a Vertec. Blood lactate samples were taken both before the Wingate protocol and after. Each subject’s perceived level of energy, focus, fatigue and anxiety/restlessness was self reported on a visual analog scale (VAS) once upon arrival, 20 minutes after ingestion of the treatment, and after the completion of the Wingate protocol. Results: Age: 23.3+4.2 (years), Height, 69+2.9 (inches); Weight, 199.6+33.9 (pounds); Body Fat, 21.6+8.9 (%); Fat Free Mass, 155.2+23.5 (pounds); and Reach, 87.2+4.5 (inches). The supplement treatment resulted in the highest average maximum (Supp: 783.1+155.7, PL+Caff: 769.8+166.5, PL: 778.2+165.8) and mean (Supp: 705+143.7, PL+Caff: 694.6+157.2, PL: 702.1+153.6) power outputs during the Wingate protocol. The results from the lactate test were F (1, 36) = 121.942 p\u3c0.0001, post hoc utilizing LSD resulted in significance (P=0.029), in that the placebo + caffeine treatment showed an higher increase in pre to post Wingate lactate compared to the other two treatments. VAS results showed the supplement treatment resulted in a higher average level of perceived energy and focus, as well as a lower average level of perceived fatigue both 20 minutes after ingestion of the treatments and after the Wingate bike test compared to the subject’s arrival for testing. Discussion: The results suggest the pre-workout supplement, Assault Black, may increase an individual’s average maximum and average mean power production during acute, high intensity physical activity. The results also suggest the supplement provides an increase in an individual’s average feeling of energy and focus as well as lowers the individual’s average level of fatigue. Even though the increases are not statistical significant during this acute study, these increases in performance, even though small, can possibly accumulate over time, adding up to larger performance increases with time

AN EXAMINATION OF THE EFFECTS OF BILATERAL AND UNILATERAL VERY SHORT-TERM DCER TRAINING ON STRENGTH AND NEUROMUSCULAR RESPONSES WITHIN THE LOWER LIMB BILATERAL DEFICIT

The very short-term resistance training (VST) model, utilizing only 2-3 training sessions, has been used to examine early phase skeletal muscle, neural, and performance adaptations. The VST model has previously been used to examine these early phase adaptations in bilateral and unilateral, isometric, isokinetic, and dynamic muscle actions in the limbs of the upper- and lower-body. The bilateral deficit (BLD) is a phenomenon in which the sum of the forces produced unilaterally is greater than the force produced bilaterally during maximal contraction of the limbs. The appearance of a bilateral deficit has been be related to various factors; including training status and mode of training (bilateral versus reciprocal muscle actions). No previous study, however, has examined the effects of VST on the BLD. The VST model has potential implications for examining acute changes in strength and neuromuscular responses of the trained muscles. These adaptations, however, may be specific to unilateral or bilateral training. Therefore, the purposes of this study were to: 1) examine one repetition maximum (1RM) strength and neuromuscular responses (EMG AMP, EMG MPF, MMG AMP, MMG MPF) during the measurement of bilateral and unilateral leg extension exercise before and after dynamic constant external resistance (DCER) VST; 2) examine the magnitude of the BLD; 3) examine the effect of bilateral versus unilateral training on the BLD; and 4) use the neuromuscular responses measured bilaterally and unilaterally to infer about the motor unit activation strategies that may underlie the BLD and changes in 1RM strength. Twenty-four (14 males, 10 females) subjects (mean ± SD age: 23.0 ± 3.2 yr; height: 174.7 ± 8.5 cm; body mass: 75.4 ± 14.1 kg) with no resistance training experience within the last three months were randomly assigned to either the bilateral (BL) training group or the unilateral (UL) training group. The subjects completed a total of seven visits, consisting of a familiarization, pre-test visit, three training visits, and one post-test visit. The pre-test visit was used to record the subject’s electromyographic (EMG) and mechanomyographic (MMG) responses from the right and left vastus lateralis (VL) during bilateral and unilateral seated maximum isometric voluntary contractions (MVIC) and 1RM. Visits four through six were the training sessions, with each subject preforming 5 sets of 6 repetitions utilizing 65% of the 1RM for resistance where the BL group trained both limbs (right and left) at the same time and the UL group trained both limbs separately. Visit seven was the post-test and the same testing procedures as the pre-test visit were followed. Statistical analyses consisted of four-way and three-way mixed model ANOVAs, with follow up three-, two- and one-way repeated measures and/or mixed model ANOVAs, Bonferroni corrected paired, and independent samples t-tests when appropriate. An alpha level of P ≤ 0.05 was considered statistically significant for all ANOVAs. The BL group demonstrated a significant increase (p = 0.006; 6.8%) in BL1RM pre- to post-test, but no change in unilateral summed (US1RM = right + left limb; p = 0.726) 1RM strength. The UL group demonstrated an 8.7% increase in BL strength collapsed across testing mode (BL1RM and US1RM) (p = 0.0001) and UL strength (p = 0.0001) collapsed across limb (UL left + UL right/2) from pre- to post-test. The BL group had a significant (p = 0.001) increase in the BI (indicating a decrease in the BLD) from pre- to post-test, but there was no significant change for the UL group. The BL group demonstrated a significant (p = 0.029) decrease in the EMG mean power frequency (MPF) measurement pre- to post-test, however the UL group showed no change. The unilateral movement, collapsed across limbs (unilateral left and unilateral right) also showed a significant (p = 0.022) decrease in the MMG MPF measurement pre- to post-test, whereas the BL movement showed no change. These findings indicated that BL and UL DCER training increased strength after 3 training sessions. The bilateral DCER training resulted in bilateral, but not unilateral strength increases and unilateral DCER training resulting in both bilateral and unilateral strength increases. However, bilateral training was the only mode of training that significantly decreased the BLD

Design of an Automobile Passenger Weighing System

The purpose of this project was to design a low-cost alternative to the current design of a device that weighs the passengers of an automobile in order to determine if the passenger weight is sufficient to deploy an airbag. In addition to designing a system to weigh a passenger, the capability of determining the position of the occupant was also desirable. Taking into account that seat deflection is a function of weight, linear potentiometers were used to measure deflection. Seven potentiometers were attached to a wire mesh located beneath the foam of the seat. Various weights were applied to locations on the seat and the voltages of the seven potentiometers were recorded. This data was then inserted into several different models in order to find a model that best determined the weight. It was found that the front-back location of the weight could be accurately determined by a least squares curve fit of the potentiometer voltages. By knowing the location zone of the weight, it was found that the weight could be determined using a different linear curve fit for each particular zone. It was found that fewer than seven potentiometers were required to obtain satisfactory results

Oxford Realism

Oxford’s own brand of realism (or anti-idealism) flourished from around the turn of the last century until John Cook Wilson’s death in 1915. Other, but related, varieties arose in roughly the same period, first in Frege, then in Cambridge. Some strands of Oxford’s brand flourished there until much later, and continue now, for example in the form of what has come by the name ‘disjunctivism’ (particularly about knowledge). Others died out, at least in Oxford. Cook Wilson and his student, H. A. Prichard, were the first leading Oxford exponents. Their realism centred on knowledge and perception, as opposed to Frege’s, which centred on the objectivity of truth. (A matter of emphasis.) This realism, both at Oxford and at Cambridge, proved fragile. Russell, for example, was soon to endorse the idea that the only genuine singular thoughts were about Vorstellungen in Frege’s sense. By the 1930s, Prichard had very self-consciously come to hold that the only true objects of perception were Vorstellungen. This essay sets out realism’s vicissitudes at Oxford, and offers a diagnosis of its fragility, to wit: until Austin’s working out of one leading idea in Cook Wilson, the tools for preserving it (the idea of the occasion-sensitivity of what is said in speaking of things being thus and so) were simply not available

Quadrature noise in light propagating through a cold 87Rb atomic gas

We report on the study of the noise properties of laser light propagating through a cold 87Rb atomic sample held in a magneto-optical trap. The laser is tuned around the Fg = 2 \rightarrow Fe = 1, 2 D1 transitions of 87Rb. We observe quadrature-dependent noise in the light signal, an indication that it may be possible to produce squeezed states of light. We measure the minimum and maximum phase-dependent noise as a function of detuning and compare these results to theoretical predictions to explore the best conditions for light squeezing using cold atomic Rb