Probing Dark Energy with Baryonic Acoustic Oscillations from Future Large Galaxy Redshift Surveys

We show that the measurement of the baryonic acoustic oscillations in large high redshift galaxy surveys offers a precision route to the measurement of dark energy. The cosmic microwave background provides the scale of the oscillations as a standard ruler that can be measured in the clustering of galaxies, thereby yielding the Hubble parameter and angular diameter distance as a function of redshift. This, in turn, enables one to probe dark energy. We use a Fisher matrix formalism to study the statistical errors for redshift surveys up to z=3 and report errors on cosmography while marginalizing over a large number of cosmological parameters including a time-dependent equation of state. With redshifts surveys combined with cosmic microwave background satellite data, we achieve errors of 0.037 on Omega_x, 0.10 on w(z=0.8), and 0.28 on dw(z)/dz for cosmological constant model. Models with less negative w(z) permit tighter constraints. We test and discuss the dependence of performance on redshift, survey conditions, and fiducial model. We find results that are competitive with the performance of future supernovae Ia surveys. We conclude that redshift surveys offer a promising independent route to the measurement of dark energy.Comment: submitted to ApJ, 24 pages, LaTe

Proceedings of the 33rd Annual Meeting, Southern Soybean Disease Workers (March 8-9, 2006, Jackson, Tennessee)

Contents Southern Soybean Disease Workers 2005 treasury report Southern United States Soybean Disease Loss Estimates for 2005. Compiled by SR Koenning Virulence in Phytopbthora sojae Isolates to Soybeans with Rps8 Resistance. DA Smith, TS Abney, and JG Shannon New Sources of Resistance to SCN in Soybean. PR Arelli Soybean Disease Management in Louisiana. B Padgett, MA Purvis, and BW Garber Efficacy and Profitability of Foliar Fungicide in the Absence of Soybean Rust. M Newman and W Percell Fungicide and Insecticide Combinations for Enhancing Soybean Health and Yield. RP Mulrooney and RW Taylor Overview of Soybean Rust Monitoring in the US. JC Rupe Yield Enhancement of Probable Asian Soybean Rust Control Fungicides. JB Blessitt, DH Poston, GL Sciumbato, CH Koger, and N Buehring Occurrence of Disease and Insect Pests in Select Sorghum and Soybean Rotations in Mississippi. ST Pichardo, RE Baird, and HN Pitre A Preliminary Evaluation of Spore Trapping Technology for Phakopsora pachyrhizi. EP Mumma, RW Schneider, CL Robertson, CG Giles, JJ Marois, and DL Wright Influence of Host Genotype and Soybean Cyst Nematode on Charcoal Rot of Soybean. TM Dorton, JP Bond, ME Schmidt, CM Vick, and AK Gregor Comparison of Disease Assessments of Soybean Genotypes in the Presence of Charcoal Rot. A Mengistu, RL Paris, JR Smith, and JD Ray Twenty Years of Soybean Variety Testing for SDS. C Schmidt, J Klein, M Schmidt, and J Bond SCN-Resistant Soybeans Offer a False Sense of Security to Producers. R Heinz, LE Sweets, and MG Mitchum Roundup Ready and Conventional Soybeans with Broad Resistance to SCN HG Types. JG Shannon, JA Wrather, DA Sleper, HT Nguyen, and SC Anand A Review ofReniform Nematode Resistance on Soybean. RT Robbins Effect of Seed Treatments on Soybean Stand and Yield in Arkansas, 2005. JC Rupe, CS Rothrock, TL Kirkpatrick, ML Rosso, and AJ Steger Inheritance of Resistance to Phomopsis Seed Decay in Soybean PI 360841. SE Smith, P Fenn, PK Miller, and P Chen Proceedings of the Southern Soybean Disease Workers are published annually by the Southern Soybean Disease Workers. Text, references, figures, and tables are reproduced as they were submitted by authors. The opinions expressed by the participants at this conference are their own and do not necessarily represent those of the Southern Soybean Disease Workers. Mention of a trademark or proprietary products in this publication does not constitute a guarantee, warranty, or endorsement of that product by the Southern Soybean Disease Workers

Automated detection of atrial fibrillation using RR intervals and multivariate-based classification

Automated detection of AF from the electrocardiogram (ECG) still remains a challenge. In this study, we investigated two multivariate-based classification techniques, Random Forests (RF) and k-nearest neighbor (k-nn), for improved automated detection of AF from the ECG. We have compiled a new database from ECG data taken from existing sources. R-R intervals were then analyzed using four previously described R-R irregularity measurements: (1) the coefficient of sample entropy (CoSEn), (2) the coefficient of variance (CV), (3) root mean square of the successive differences (RMSSD), and (4) median absolute deviation (MAD). Using outputs from all four R-R irregularity measurements, RF and k-nn models were trained. RF classification improved AF detection over CoSEn with overall specificity of 80.1% vs. 98.3% and positive predictive value of 51.8% vs. 92.1% with a reduction in sensitivity, 97.6% vs. 92.8%. k-nn also improved specificity and PPV over CoSEn; however, the sensitivity of this approach was considerably reduced (68.0%)

The effects of 40 Hz low-pass filtering on the spatial QRS-T angle

The spatial QRS-T angle (SA) is a vectorcardiographic (VCG) parameter that has been identified as a marker for changes in the ventricular depolarization and repolarization sequence. The SA is defined as the angle subtended by the mean QRS-vector and the mean T- vector of the VCG. The SA is typically obtained from VCG data that is derived from the resting 12-lead electrocardiogram (ECG). Resting 12-lead ECG data is commonly recorded using a low-pass filter with a cutoff frequency of 150 Hz. The ability of the SA to quantify changes in the ventricular depolarization and repolarization sequence make the SA potentially attractive in a number of different 12-lead ECG monitoring applications. However, the 12-lead ECG data that is obtained in such monitoring applications is typically recorded using a low-pass filter cutoff frequency of 40 Hz. The aim of this research was to quantify the differences between the SA computed using 40 Hz low- pass filtered ECG data (SA40) and the SA computed using 150 Hz low-pass filtered ECG data (SA150). We assessed the difference between the SA40 and the SA150 using a study population of 726 subjects. The differences between the SA40 and the SA150 were quantified as systematic error (mean difference) and random error (span of Bland-Altman 95% limits of agreement). The systematic error between the SA40 and the SA150 was found to be -0.126° [95% confidence interval: -0.146° to - 0.107°]. The random error was quantified 1.045° [95% confidence interval: 0.917° to 1.189°]. The findings of this research suggest that it is possible to accurately determine the value of the SA when using 40 Hz low-pass filtered ECG data. This finding indicates that it is possible to record the SA in applications that require the utilization of 40 Hz low-pass ECG monitoring filters

Proceedings of the 35th Annual Meeting, Southern Soybean Disease Workers (March 12-13, 2008, Pensacola, Florida)

Contents Southern United States Soybean Disease Loss Estimate for 2007. Compiled by SR Koenning Contributed papers (Clayton Hollier, moderator) Effects of Row Spacing and Leaf Wetness on the Temporal and Spatial Spread of Soybean Rust within Soybean Canopies. DF Narváez, JJ Marois, DL Wright, and S Isard Effects of Potassium, Chloride, and Minor Elements Nutrition on Asian Soybean Rust. RW Schneider, EP Mumma, CL Clark, and CG Giles The Impact of Selected Fungicide Treatments on Disease Progress of Asian Soybean Rust and Other Diseases of Soybean. GB Padgett, MA Purvis, A Hogan, and S Martin Soybean Sudden Death Syndrome Variety Testing at Southern Illinois University. C Herzog, C Schmidt, and M Schmidt Soybean Yield Suppression Due to Diseases for the Top Eight Soybean-Producing Countries in 2006. A Wrather, S Koenning, R Balardin, LH Carregal, R Escobar, GK Gupta, Z Ma, W Morel, LD Ploper, and A Tenuta Impact of Frogeye Leaf Spot on Soybean Yield in the Lower Midwest. CM Vick, AK Vick, JP Bond, and JA Wrather Graduate student papers (Alemu Mengistu, moderator) Laboratory Evaluation of Soybean Resistance to Pod Blight Caused by Cercospora kikuchii. BC Wells and GL Sciumbato Temporal Dynamics of Root and Foliar Symptoms of Soybean Sudden Death Syndrome at Different Inoculum Densities. C Gongora-Canul, FW Nutter, Jr, and LFS Leandro Discussion session (Allen Wrather, moderator) Soybean Rust Sentinal Survey discussion. Don Hershman Proceedings of the Southern Soybean Disease Workers are published annually by the Southern Soybean Disease Workers. Text, references, figures, and tables are reproduced as they were submitted by authors. The opinions expressed by the participants at this conference are their own and do not necessarily represent those of the Southern Soybean Disease Workers. Mention of a trademark or proprietary products in this publication does not constitute a guarantee, warranty, or endorsement of that product by the Southern Soybean Disease Workers

Improving Cosmological Distance Measurements by Reconstruction of the Baryon Acoustic Peak

The baryon acoustic oscillations are a promising route to the precision measure of the cosmological distance scale and hence the measurement of the time evolution of dark energy. We show that the non-linear degradation of the acoustic signature in the correlations of low-redshift galaxies is a correctable process. By suitable reconstruction of the linear density field, one can sharpen the acoustic peak in the correlation function or, equivalently, restore the higher harmonics of the oscillations in the power spectrum. With this, one can achieve better measurements of the acoustic scale for a given survey volume. Reconstruction is particularly effective at low redshift, where the non-linearities are worse but where the dark energy density is highest. At z=0.3, we find that one can reduce the sample variance error bar on the acoustic scale by at least a factor of 2 and in principle by nearly a factor of 4. We discuss the significant implications our results have for the design of galaxy surveys aimed at measuring the distance scale through the acoustic peak.Comment: 5 pages, LaTeX. Submitted to the Astrophysical Journa

The effects of electrode placement on an automated algorithm for the detection of ST segment changes on the 12-lead ECG

In this study we investigate the effect that ECG electrode placement can have on the detection of ST segment changes. BSPMs from 45 subjects undergoing PTCA were analysed (15 left anterior descending, 15 left circumflex and 15 right coronary artery). 12-lead ECG were extracted from BSPMs corresponding with correct precordial electrode positioning and corresponding with simultaneous vertical movement of all of the precordial leads in 5mm increments up to +/-50mm away from the correct position. A computer algorithm was developed based on current guidelines for the detection of STEMI and Non-STEMI. This algorithm was applied to all of the extracted 12-lead ECGs. Median sensitivity and specificity, based upon all baseline versus all peak balloon inflation cases, were calculated for results generated at each electrode position. With the precordial leads positioned correctly the sensitivity and specificity were 51.1% and 91.1% respectively. When all precordial leads were placed 50mm superior to their correct position the sensitivity increased to 57.8% whilst specificity remained unchanged. At 50mm inferior to the correct position the sensitivity and specificity were 46.7% and 88.9% respectively. The results show a variation of more than 10% in sensitivity when the electrodes are moved up to 100mm vertically

On the derivation of the spatial QRS-T angle from Mason-Likar leads I, II, V2 and V5

The spatial QRS-T angle (SA) has been identified as a marker for changes in the ventricular depolarization and repolarization sequence. The determination of the SA requires vectorcardiographic (VCG) data. However, VCG data is seldom recorded in monitoring applications. This is mainly due to the fact that the number and location of the electrodes required for recording the Frank VCG complicate the recording of VCG data in monitoring applications. Alternatively, reduced lead systems (RLS) allow for the derivation of the Frank VCG from a reduced number of electrocardiographic (ECG) leads. Derived Frank VCGs provide a practical means for the determination of the SA in monitoring applications. One widely studied RLS that is used in clinical practice is based upon Mason-Likar leads I, II, V2 and V5 (MLRL). The aim of this research was two-fold. First, to develop a linear ECG lead transformation matrix that allows for the derivation of the Frank VCG from the MLRL system. Second, to assess the accuracy of the MLRL derived SA (MSA). We used ECG data recorded from 545 subjects for the development of the linear ECG lead transformation matrix. The accuracy of the MSA was assessed by analyzing the differences between the MSA and the SA using the ECG data of 181 subjects. The differences between the MSA and the SA were quantified as systematic error (mean difference) and random error (span of Bland-Altman 95% limits of agreement). The systematic error between the MSA and the SA was found to be 9.38° [95% confidence interval: 7.03° to 11.74°]. The random error was quantified as 62.97° [95% confidence interval: 56.55° to 70.95°]

All-sky convolution for polarimetry experiments

We discuss all-sky convolution of the instrument beam with the sky signal in polarimetry experiments, such as the Planck mission which will map the temperature anisotropy and polarization of the cosmic microwave background (CMB). To account properly for stray light (from e.g. the galaxy, sun, and planets) in the far side-lobes of such an experiment, it is necessary to perform the beam convolution over the full sky. We discuss this process in multipole space for an arbitrary beam response, fully including the effects of beam asymmetry and cross-polarization. The form of the convolution in multipole space is such that the Wandelt-Gorski fast technique for all-sky convolution of scalar signals (e.g. temperature) can be applied with little modification. We further show that for the special case of a pure co-polarized, axisymmetric beam the effect of the convolution can be described by spin-weighted window functions. In the limits of a small angle beam and large Legendre multipoles, the spin-weight 2 window function for the linear polarization reduces to the usual scalar window function used in previous analyses of beam effects in CMB polarimetry experiments. While we focus on the example of polarimetry experiments in the context of CMB studies, we emphasise that the formalism we develop is applicable to anisotropic filtering of arbitrary tensor fields on the sphere.Comment: 8 pages, 1 figure; Minor changes to match version accepted by Phys. Rev.

A Period and a Prediction for the Of?p Spectrum Alternator HD 191612

The observational picture of the enigmatic O-type spectrum variable HD191612 has been sharpened substantially. A symmetrical, low-amplitude light curve with a period near 540 d has recently been reported from Hipparcos photometry. This period satisfies all of the spectroscopy since at least 1982, including extensive new observations during 2003 and 2004, and it has predicted the next transition during September--October 2004. Measurements of the H alpha equivalent width reveal a sharp emission peak in the phase diagram, in contrast to the apparently sinusoidal light curve. The He II absorption-line strength is essentially constant, while He I varies strongly, possibly filled in by emission in the O6 state, thus producing the apparent spectral-type variations. The O8 state appears to be the "normal" one. Two intermediate O7 observations have been obtained, which fall at the expected phases, but these are the only modern observations of the transitions so far. The period is too long for rotation or pulsation; although there is no direct evidence as yet for a companion, a model in which tidally induced oscillations drive an enhanced wind near periastron of an eccentric orbit appears promising. Further observations during the now predictable transitions may provide a critical test. Ultraviolet and X-ray observations during both states will likely also prove illuminating.Comment: 7 pages, 3 figures, 1 table; scheduled for the 2004 December 10 issue of ApJL, Vol. 617, No. 1. ApJ