Herbicide Evaluation in Arkansas Cotton, 1999

Herbicidal weed control is economically important for production of cotton. Field experiments are conducted annually in Arkansas to evaluate the activity of developmental and commercial herbicides for selective control of weeds in cotton. These experiments serve both industry and Arkansas agriculture by providing information on the selectivity of herbicides still in the developmental stage and by comparing the activity of these new herbicides with that of recommended herbicides

Interpreting Lived Experience through Writing Online in a Graduate Seminar

Participants in an online doctoral seminar participated in the use of a writing strategy to explore the sociocultural contexts of their lived experience. Creating literary texts in three forms was an effective strategy in mediating participants’ understanding. Each form provided a new lens through which to interpret experience. Participants functioned as an interpretive community. The final papers, autobiographical narratives, illuminated the complex relations among prediscursive experience, reflection on experience, distancing, and the iterative transformational quality of time. The online format embodied a virtual interpretive location which allowed participants to revisit texts and postings over time. Des participants dans un cours de doctorat en ligne, ont utilisé une stratégie de rédaction leur permettant d’explorer les contextes socioculturels de leurs expériences de vie. La création de trois formes de textes littéraires s’est avèrée une stratégie efficace pour faciliter la compréhension des participants. Chaque forme littéraire a offert de nouvelle perspectives aux étudiants pour interpréter leurs expériences. Les participants dans cette communauté ont pu interpréter collectivement leurs expériences de vie. Les textes finaux, qui ont pris la forme de narratifs autobiographiques ont illustré la complexité des relations qui existent entre une expérience pré-réfléchie, la réflexion sur l’expérience, la capacité de prendre de la distance face a l’expérience. Dans ces mêmes textes on y trouve la nature réitérée et la qualitée transformative du temps. Le format en ligne a crée un endroit virtuel interprétatif qui a permis aux participants de revisiter les textes et les messages affichés dans le temps

Herbicide Evaluation in Arkansas Cotton 2000

Herbicidal weed control is economically important for production of cotton. Field experiments are conducted annually in Arkansas to evaluate the activity of developmental and commercial herbicides for selective control of weeds in cotton. These experiments serve both industry and Arkansas agriculture by providing information on the selectivity of herbicides still in the developmental stage and by comparing the activity of these new herbicides with that of recommended herbicides

Herbicide Evaluation in Arkansas Rice 2000

With the widespread development of resistance to propanil by barnyardgrass, the major weed in rice, research has been intensified in recent years to develop alternative weed control technology to the repeated use of propanil. The use of herbicides is economically important for production of rice. Field experiments are conducted annually in Arkansas to evaluate the activity of developmental and commercial herbicides for selective control of barnyardgrass and other weeds in rice. These experiments serve both industry and Arkansas agriculture by providing information on the selectivity of herbicides still in the developmental stage and by comparing the activity of these new herbicides with that of recommended herbicides

The Low-Velocity, Rapidly Fading Type Ia Supernova 2002es

SN 2002es is a peculiar subluminous Type Ia supernova (SN Ia) with a combination of observed characteristics never before seen in a SN Ia. At maximum light, SN 2002es shares spectroscopic properties with the underluminous SN 1991bg subclass of SNe Ia, but with substantially lower expansion velocities (~6000 km/s) more typical of the SN 2002cx subclass. Photometrically, SN 2002es differs from both SN 1991bg-like and SN 2002cx-like supernovae. Although at maximum light it is subluminous (M_B=-17.78 mag), SN 2002es has a relatively broad light curve (Dm15(B)=1.28 +/- 0.04 mag), making it a significant outlier in the light-curve width vs. luminosity relationship. We estimate a 56Ni mass of 0.17 +/- 0.05 M_sun synthesized in the explosion, relatively low for a SN Ia. One month after maximum light, we find an unexpected plummet in the bolometric luminosity. The late-time decay of the light curves is inconsistent with our estimated 56Ni mass, indicating that either the light curve was not completely powered by 56Ni decay or the ejecta became optically thin to gamma-rays within a month after maximum light. The host galaxy is classified as an S0 galaxy with little to no star formation, indicating the progenitor of SN 2002es is likely from an old stellar population. We also present a less extensive dataset for SN 1999bh, an object which shares similar observed properties. Both objects were found as part of the Lick Observatory Supernova Search, allowing us to estimate that these objects should account for ~2.5% of SNe Ia within a fixed volume. We find that current theoretical models are unable to explain the observed of characteristics of SN 2002es.Comment: 19 pages, 15 figures, Submitted to Ap

Distorted wave impulse approximation analysis for spin observables in nucleon quasi-elastic scattering and enhancement of the spin-longitudinal response

We present a formalism of distorted wave impulse approximation (DWIA) for analyzing spin observables in nucleon inelastic and charge exchange reactions leading to the continuum. It utilizes response functions calculated by the continuum random phase approximation (RPA), which include the effective mass, the spreading widths and the \Delta degrees of freedom. The Fermi motion is treated by the optimal factorization, and the non-locality of the nucleon-nucleon t-matrix by an averaged reaction plane approximation. By using the formalism we calculated the spin-longitudinal and the spin-transverse cross sections, ID_q and ID_p, of 12C, 40Ca (\vec{p},\vec{n}) at 494 and 346 MeV. The calculation reasonably reproduced the observed ID_q, which is consistent with the predicted enhancement of the spin-longitudinal response function R_L. However, the observed ID_p is much larger than the calculated one, which was consistent with neither the predicted quenching nor the spin-transverse response function R_T obtained by the (e,e') scattering. The Landau-Migdal parameter g'_N\Delta for the N\Delta transition interaction and the effective mass at the nuclear center m^*(r=0) are treated as adjustable parameters. The present analysis indicates that the smaller g'_{N\Delta}(\approx 0.3) and m^*(0) \approx 0.7 m are preferable. We also investigate the validity of the plane wave impulse approximation (PWIA) with the effective nucleon number approximation for the absorption, by means of which R_L and R_T have conventionally been extracted.Comment: RevTex 3, 29 pages, 2 tables, 8 figure

Cleavage of a model DNA replication fork by a Type I restriction endonuclease

Cleavage of a DNA replication fork leads to fork restoration by recombination repair. In prokaryote cells carrying restriction–modification systems, fork passage reduces genome methylation by the modification enzyme and exposes the chromosome to attack by the restriction enzyme. Various observations have suggested a relationship between the fork and Type I restriction enzymes, which cleave DNA at a distance from a recognition sequence. Here, we demonstrate that a Type I restriction enzyme preparation cleaves a model replication fork at its branch. The enzyme probably tracks along the DNA from an unmethylated recognition site on the daughter DNA and cuts the fork upon encountering the branch point. Our finding suggests that these restriction–modification systems contribute to genome maintenance through cell death and indicates that DNA replication fork cleavage represents a critical point in genome maintenance to choose between the restoration pathway and the destruction pathway

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

A Cryogenic Silicon Interferometer for Gravitational-wave Detection

The detection of gravitational waves from compact binary mergers by LIGO has opened the era of gravitational wave astronomy, revealing a previously hidden side of the cosmos. To maximize the reach of the existing LIGO observatory facilities, we have designed a new instrument able to detect gravitational waves at distances 5 times further away than possible with Advanced LIGO, or at greater than 100 times the event rate. Observations with this new instrument will make possible dramatic steps toward understanding the physics of the nearby Universe, as well as observing the Universe out to cosmological distances by the detection of binary black hole coalescences. This article presents the instrument design and a quantitative analysis of the anticipated noise floor