Hyperspectral classification of Cyperus esculentus clones and morphologically similar weeds

Cyperus esculentus (yellow nutsedge) is one of the world's worst weeds as it can cause great damage to crops and crop production. To eradicate C. esculentus, early detection is key-a challenging task as it is often confused with other Cyperaceae and displays wide genetic variability. In this study, the objective was to classify C. esculentus clones and morphologically similar weeds. Hyperspectral reflectance between 500 and 800 nm was tested as a measure to discriminate between (I) C. esculentus and morphologically similar Cyperaceae weeds, and between (II) different clonal populations of C. esculentus using three classification models: random forest (RF), regularized logistic regression (RLR) and partial least squares-discriminant analysis (PLS-DA). RLR performed better than RF and PLS-DA, and was able to adequately classify the samples. The possibility of creating an affordable multispectral sensing tool, for precise in-field recognition of C. esculentus plants based on fewer spectral bands, was tested. Results of this study were compared against simulated results from a commercially available multispectral camera with four spectral bands. The model created with customized bands performed almost equally well as the original PLS-DA or RLR model, and much better than the model describing multispectral image data from a commercially available camera. These results open up the opportunity to develop a dedicated robust tool for C. esculentus recognition based on four spectral bands and an appropriate classification model

A Spectroscopic Survey of Faint Quasars in the SDSS Deep Stripe: I. Preliminary Results from the Co-added Catalog

In this paper we present the first results of a deep spectroscopic survey of faint quasars in the Sloan Digital Sky Survey (SDSS) Southern Survey, a deep survey carried out by repeatedly imaging a 270 deg^2 area. Quasar candidates were selected from the deep data with good completeness over 0<z<5, and 2 to 3 magnitudes fainter than the SDSS main survey. Spectroscopic follow-up was carried out on the 6.5m MMT with Hectospec. The preliminary sample of this SDSS faint quasar survey (hereafter SFQS) covers ~ 3.9 deg^2, contains 414 quasars, and reaches g=22.5. The overall selection efficiency is ~ 66% (~ 80% at g<21.5); the efficiency in the most difficult redshift range (2<z<3) is better than 40%. We use the 1/V_{a} method to derive a binned estimate of the quasar luminosity function (QLF) and model the QLF using maximum likelihood analysis. The best model fits confirm previous results showing that the QLF has steep slopes at the bright end and much flatter slopes (-1.25 at z<2.0 and -1.55 at z>2.0) at the faint end, indicating a break in the QLF slope. Using a luminosity-dependent density evolution model, we find that the quasar density at M_{g}<-22.5 peaks at z~2, which is later in cosmic time than the peak of z~2.5 found from surveys of more luminous objects. The SFQS QLF is consistent with the results of the 2dF QSO Redshift Survey, the SDSS, and the 2dF-SDSS LRG and QSO Survey, but probes fainter quasars. We plan to obtain more quasars from future observations and establish a complete faint quasar sample with more than 1000 objects over 10 deg^2.Comment: 25 pages, 13 figures, accepted for publication in A

Marine and Hydrokinetic Renewable Energy Technologies: Potential Navigational Impacts and Mitigation Measures

On April 15, 2008, the Department of Energy (DOE) issued a Funding Opportunity Announcement for Advanced Water Power Projects which included a Topic Area for Marine and Hydrokinetic Renewable Energy Market Acceleration Projects. Within this Topic Area, DOE identified potential navigational impacts of marine and hydrokinetic renewable energy technologies and measures to prevent adverse impacts on navigation as a sub-topic area. DOE defines marine and hydrokinetic technologies as those capable of utilizing one or more of the following resource categories for energy generation: ocean waves; tides or ocean currents; free flowing water in rivers or streams; and energy generation from the differentials in ocean temperature. PCCI was awarded Cooperative Agreement DE-FC36-08GO18177 from the DOE to identify the potential navigational impacts and mitigation measures for marine hydrokinetic technologies, as summarized herein. The contract also required cooperation with the U.S. Coast Guard (USCG) and two recipients of awards (Pacific Energy Ventures and reVision) in a sub-topic area to develop a protocol to identify streamlined, best-siting practices. Over the period of this contract, PCCI and our sub-consultants, David Basco, Ph.D., and Neil Rondorf of Science Applications International Corporation, met with USCG headquarters personnel, with U.S. Army Corps of Engineers headquarters and regional personnel, with U.S. Navy regional personnel and other ocean users in order to develop an understanding of existing practices for the identification of navigational impacts that might occur during construction, operation, maintenance, and decommissioning. At these same meetings, “standard” and potential mitigation measures were discussed so that guidance could be prepared for project developers. Concurrently, PCCI reviewed navigation guidance published by the USCG and international community. This report summarizes the results of this effort, provides guidance in the form of a checklist for assessing the navigational impacts of potential marine and hydrokinetic projects, and provides guidance for improving the existing navigational guidance promulgated by the USCG in Navigation Vessel Inspection Circular 02 07. At the request of the USCG, our checklist and mitigation guidance was written in a generic nature so that it could be equally applied to offshore wind projects. PCCI teleconferenced on a monthly basis with DOE, Pacific Energy Ventures and reVision in order to share information and review work products. Although the focus of our effort was on marine and hydrokinetic technologies, as defined above, this effort drew upon earlier work by the USCG on offshore wind renewable energy installations. The guidance provided herein can be applied equally to marine and hydrokinetic technologies and to offshore wind, which are collectively referred to by the USCG as Renewable Energy Installations

Triple-Pomeron Matrix Model for Dispersive Corrections to Nucleon-Nucleus Total Cross Section

Dispersive corrections to the total cross section for high-energy scattering from a heavy nucleus are calculated using a matrix model, based on the triple-Pomeron behavior of diffractive scattering from a single nucleon, for the cross section operator connecting different states of the projectile nucleon . Energy-dependent effects due to the decrease in longitudinal momentum transfers and the opening of more channels with increasing energy are included. The three leading terms in an expansion in the number of inelastic transitions are evaluated and compared to exact results for the model in the uniform nuclear density approximation for the the scattering of nucleons from Pb^{208} for laboratory momenta ranging from 50 to 200 GeV/c.Comment: 16 pages, 2 figures, RevTex

THE DISTANCE TO THE MASSIVE GALACTIC CLUSTER WESTERLUND 2 FROM A SPECTROSCOPIC AND HST PHOTOMETRIC STUDY , ,

We present a spectroscopic and photometric determination of the distance to the young Galactic open cluster Westerlund 2 using WFPC2 imaging from the Hubble Space Telescope (HST) and ground-based optical spectroscopy. HST imaging in the F336W, F439W, F555W, and F814W filters resolved many sources previously undetected in ground-based observations and yielded photometry for 1136 stars. We identified 15 new O-type stars, along with two probable binary systems, including MSP 188 (O3 + O5.5). We fit reddened spectral energy distributions based on the Padova isochrones to the photometric data to determine individual reddening parameters RV and AV for O-type stars in Wd2. We find average values RV = 3.77 ± 0.09 and AV = 6.51 ± 0.38 mag, which result in a smaller distance than most other spectroscopic and photometric studies. After a statistical distance correction accounting for close unresolved binaries (factor of 1.08), our spectroscopic and photometric data on 29 O-type stars yield that Westerlund 2 has a distance d = 4.16 ± 0.07 (random) +0.26 (systematic) kpc. The cluster's age remains poorly constrained, with an upper limit of 3 Myr. Finally, we report evidence of a faint mid-IR polycyclic aromatic hydrocarbon ring surrounding the well-known binary candidate MSP 18, which appears to lie at the center of a secondary stellar grouping within Westerlund 2

Cancer-related ectopic expression of the bone-related transcription factor RUNX2 in non-osseous metastatic tumor cells is linked to cell proliferation and motility

10.1186/bcr2762Breast Cancer Research125-BCRR

Evolution of the velocity-dispersion function of luminous red galaxies: a hierarchical Bayesian measurement

We present a hierarchical Bayesian determination of the velocity-dispersion function of approximately 430,000 massive luminous red galaxies observed at relatively low spectroscopic signal-to-noise ratio (S/N ~ 3–5 per 69 km s−1) by the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III. We marginalize over spectroscopic redshift errors, and use the full velocity-dispersion likelihood function for each galaxy to make a self-consistent determination of the velocity-dispersion distribution parameters as a function of absolute magnitude and redshift, correcting as well for the effects of broadband magnitude errors on our binning. Parameterizing the distribution at each point in the luminosity–redshift plane with a log-normal form, we detect significant evolution in the width of the distribution toward higher intrinsic scatter at higher redshifts. Using a subset of deep re-observations of BOSS galaxies, we demonstrate that our distribution-parameter estimates are unbiased regardless of spectroscopic S/N. We also show through simulation that our method introduces no systematic parameter bias with redshift. We highlight the advantage of the hierarchical Bayesian method over frequentist “stacking” of spectra, and illustrate how our measured distribution parameters can be adopted as informative priors for velocity-dispersion measurements from individual noisy spectra

The Fifth Data Release of the Sloan Digital Sky Survey

This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and represents the completion of the SDSS-I project (whose successor, SDSS-II will continue through mid-2008). It includes five-band photometric data for 217 million objects selected over 8000 square degrees, and 1,048,960 spectra of galaxies, quasars, and stars selected from 5713 square degrees of that imaging data. These numbers represent a roughly 20% increment over those of the Fourth Data Release; all the data from previous data releases are included in the present release. In addition to "standard" SDSS observations, DR5 includes repeat scans of the southern equatorial stripe, imaging scans across M31 and the core of the Perseus cluster of galaxies, and the first spectroscopic data from SEGUE, a survey to explore the kinematics and chemical evolution of the Galaxy. The catalog database incorporates several new features, including photometric redshifts of galaxies, tables of matched objects in overlap regions of the imaging survey, and tools that allow precise computations of survey geometry for statistical investigations.Comment: ApJ Supp, in press, October 2007. This paper describes DR5. The SDSS Sixth Data Release (DR6) is now public, available from http://www.sdss.or