Real-world Quantum Sensors: Evaluating Resources for Precision Measurement

Quantum physics holds the promise of enabling certain tasks with better performance than possible when only classical resources are employed. The quantum phenomena present in many experiments signify nonclassical behavior, but do not always imply superior performance. Quantifying the enhancement achieved from quantum behavior requires careful analysis of the resources involved. We analyze the specific case of parameter estimation using an optical interferometer, where increased precision can be achieved using quantum probe states. Common performance measures are examined and it is shown that some overestimate the improvement. For the simplest experimental case we compare the different measures and show this overestimate explicitly. We give the preferred analysis of real-world experiments and calculate benchmark values for experimental parameters necessary to realize a precision enhancement.Comment: 8 pages, 3 figure

Age and sex-specific rates of leaf regeneration in the Mojave Desert moss Syntrichia caninervis

The extremely skewed female-biased sex ratio in the desert moss Syntrichia caninervis was investigated by assessing the regeneration capacity of detached leaves. Juvenile, green, yellow-green, and brown leaves equating to approximately 0, 2, 6, and 12 yr of age, respectively, were detached from individuals of S. caninervis collected from 10 field populations and grown in a growth chamber for 58 d at a light intensity of 33–128 µmol · m–2 · s–1. Younger leaves (0–2 yr old) tended to have a greater viability, regenerate more quickly, extend their protonemal filaments farther, produce shoots (gametophores) more quickly, produce more shoots, and accumulate a greater biomass than older leaves (6 and 12 yr old). Among younger leaf classes, regenerating female leaves were more likely to produce a shoot than male leaves and produced more shoots than male leaves. The sexes did not differ significantly in time until protonemal emergence, linear extension of protonemata, or rate of biomass accumulation. However, protonemata of male leaves tended to emerge more quickly and produce a greater total biomass, ultimately consisting mostly of protonemata, than did female leaves. The more rapid proliferation of shoots by female leaf regenerants may help to explain the rarity of males in this species

Characteristics associated with noncompliance of current pitch smart guidelines in high school baseball pitchers throughout the United States

BACKGROUND: Although pitch count and rest guidelines have been promoted for youth and adolescent baseball players for nearly 2 decades, compliance with guidelines remains poorly understood. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the frequency of compliance with Major League Baseball (MLB) Pitch Smart guidelines as well as the association between compliance and range of motion (ROM), strength, velocity, injury, and pitcher utilization. It was hypothesized that pitchers in violation of current recommendations would have increased strength, velocity, and injury. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This was a prospective, multicenter study of 115 high school pitchers throughout the United States. Pitchers were surveyed about their compliance with current off-season, rest-related guidelines, and history of injury. During the preseason, pitchers underwent standardized physical examinations, and pitch velocity was measured. Pitch counts were collected during the baseball season that followed. Dynamometer strength testing of shoulder forward flexion, and external rotation as well as grip strength was recorded. We compared pitchers who were compliant with recommendations with those who were noncompliant using Student RESULTS: Based on preseason data, 84% of pitchers had violated current Pitch Smart guidelines. During the season, 14% had at least 1 violation of the Pitch Smart guidelines. Across both the preseason survey and in-season pitch counts, 89% of players had at least 1 violation of the Pitch Smart guidelines. While there were no significant differences in ROM or strength, the noncompliant group had higher maximum pitch velocity than the compliant group (74 ± 8 vs 69 ± 5 mph [119 ± 13 vs 111 ± 8 kph], respectively; CONCLUSION: Most high school pitchers were not fully compliant with current Pitch Smart guidelines, and they tended to overestimate their peak velocity by 7 mph (11 kph). Pitchers who threw with greater velocity were at higher risk for violating Pitch Smart recommendations

The role of discharge variability in determining alluvial stratigraphy

We illustrate the potential for using physics-based modeling to link alluvial stratigraphy to large river morphology and dynamics. Model simulations, validated using ground penetrating radar data from the Río Paraná, Argentina, demonstrate a strong relationship between bar-scale set thickness and channel depth, which applies across a wide range of river patterns and bar types. We show that hydrologic regime, indexed by discharge variability and flood duration, exerts a first-order influence on morphodynamics and hence bar set thickness, and that planform morphology alone may be a misleading variable for interpreting deposits. Indeed, our results illustrate that rivers evolving under contrasting hydrologic regimes may have very similar morphology, yet be characterized by marked differences in stratigraphy. This realization represents an important limitation on the application of established theory that links river topography to alluvial deposits, and highlights the need to obtain field evidence of discharge variability when developing paleoenvironmental reconstructions. Model simulations demonstrate the potential for deriving such evidence using metrics of paleocurrent variance

Recovery of end-organs and improved mortality in adult patient on ECMO.

Title: Recovery of End-Organs and Improved Mortality in Adult Patients on ECMO Joshua K Wong, BS1, Vei Shaun Siow, BS1, Thomas N Smith, BS1, Harrison Pitcher, MD2, Linda Bogar, MD2, Hitoshi Hirose, MD2 and Nicholas C Cavarocchi, MD2. 1Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States, 19107 and 2Division of Cardiothoracic Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, United States, 19107. Body: With increasing use of ECMO in adults, we seek to objectively measure End-Organ recovery and correlate intensive care mortality scores and complications with patient survival. This is a retrospective review of patients who were placed on ECMO from Oct 2010 to Dec 2011. End-Organ function was measured through Pa02/Fi02 ratios, lactate levels, MELD and mortality scores (SAPSII/APACHEII/SOFA). Complications were recorded and analyzed. Twenty-three patients were placed on VA-ECMO and 5 on VV-ECMO. 22 (73%) patients were successfully weaned off ECMO, and 13 (46%) survived to discharge. In 12 patients with liver injury pre-ECMO, the median MELD score was 21 vs 13 post-ECMO (

Improving Case Definitions for Severe Malaria

The authors discuss a study by Philip Bejon et al. that adopted a new approach to balancing the sensitivity and specificity of criteria for defining severe malaria

Candidate Type II Quasars at 2 < z < 4.3 in the Sloan Digital Sky Survey III

At low redshifts, dust-obscured quasars often have strong yet narrow permitted lines in the rest-frame optical and ultraviolet, excited by the central active nucleus, earning the designation Type II quasars. We present a sample of 145 candidate Type II quasars at redshifts between 2 and 4.3, encompassing the epoch at which quasar activity peaked in the universe. These objects, selected from the quasar sample of the Baryon Oscillation Spectroscopic Survey of the Sloan Digital Sky Survey III, are characterized by weak continuum in the rest-frame ultraviolet (typical continuum magnitude of i \approx 22) and strong lines of CIV and Ly \alpha, with Full Width at Half Maximum less than 2000 kms-1. The continuum magnitudes correspond to an absolute magnitude of -23 or brighter at redshift 3, too bright to be due exclusively to the host galaxies of these objects. Roughly one third of the objects are detected in the shorter-wavelength bands of the WISE survey; the spectral energy distributions (SEDs) of these objects appear to be intermediate between classic Type I and Type II quasars seen at lower redshift. Five objects are detected at rest frame 6\mu m by Spitzer, implying bolometric luminosities of several times 10^46 erg s-1. We have obtained polarization measurements for two objects; they are roughly 3% polarized. We suggest that these objects are luminous quasars, with modest dust extinction (A_V ~ 0.5 mag), whose ultraviolet continuum also includes a substantial scattering contribution. Alternatively, the line of sight to the central engines of these objects may be partially obscured by optically thick material.Comment: 26 pages, 13 figures, 10 tables, 4 machine readable tables. Accepted for publication in MNRA