Blackland Prairies of Southwestern Arkansas

The Blackland Prairie community type has been described in Texas; related communities exist in Alabama and Mississippi. The Arkansas variant of the community has not been described in detail. Since the Arkansas Natural Heritage Commission began a systematic inventory of the community in 1985, more than 36 remnants have been identified that retain substantial natural character. However, all show some degree of disturbance. Based on aerial photo interpretation, aerial inspection, and ground study, an initial description of the community is presented, including original distribution, soil, vegetation and relationship to similar communities of Texas, Mississippi, and Alabama

Vegetation of Saratoga Landing Blackland Prairie

Saratoga Landing Blackland Prairie is a 75-ha site owned by the U.S. Army Corps of Engineers and managed cooperatively with the Arkansas Natural Heritage Commission to protect its blackland prairie community and rare plant species. The site is a complex of prairies and forests, as interpreted from aerial photos and maps. It was substantially prairie at the time of settlement, and forest cover did not increase greatly until after 1951, apparently due to effective suppression of wildfires after that time. Plot sampling characterizes an individual prairie on the site as being dominated by a herbaceous canopy, but with a substantial woody plant cover (15%-20%). Of the herbaceous vegetation, Andropogon scoparius is dominant, with lower seasonal production than the Grand Prairie of eastern Arkansas (147 g/m^2 vs. 800 g/m^2). A recent prescribed burn resulted in a doubling of herbaceous end-of-season biomass, top-killing (but resprouting) of many woody plants, elimination of mulch and increased bare ground

Description of the Sections and Subsections of the Interior Highlands of Arkansas and Oklahoma

Sections and subsections of the Interior Highlands of Arkansas and Oklahoma are redefined, mapped and briefly summarized. The map was produced to support the Ozark- Ouachita Highlands Assessment (OOHA), being conducted by the USDA Forest Service. It revises the USDA Forest Service map Ecological units of the eastern United States, first approximation by Keys et al. (1995) and the earlier maps of the natural divisions of Arkansas (Foti, 1974; Foti, 1976; Pell, 1983) to reflect new knowledge and to achieve consistency with units recognized in Missouri. Four sections (natural divisions) are defined as opposed to the three of the previous Arkansas natural divisions maps, and new subsections are recognized within most sections. Digital maps of geology, soils and topography were used to create the map in ARC/INFO. The map is accessible through the World Wide Web as a portion of a map of the entire Interior Highlands region of Arkansas, Oklahoma and Missouri on the home page of the Ouachita National Forest at http://www.fs.fed.us/oonf/ooha/welcome.htm

Arkansas Field Botany (Flora and Vegetation) Bibliography (1988-2000)

The floristic richness and diversity of vegetation in Arkansas continues to require and stimulate a growing body of taxonomic and ecological research publications. Peck and Peck (1988) listed 766 references, including those of the two prior lists. Since then we have gathered 417 additional references. The total list now contains 1,183 references, with 70% prepared or published since 1970. This update is provided for four reasons: 1) to compile a comprehensive source to direct and facilitate future studies, 2) to provide easier access to many reports not normally located in electronic databases, 3) to improve communications with botanists outside Arkansas, and 4) to support the ongoing and active efforts of those involved in the production of a manual to the Arkansas Vascular Flora and a book-length treatment of the vegetation of Arkansas. Future plans include placing the entire list on the Internet and developing of a means of updating the list every year

Classification System for the Natural Vegetation of Arkansas

We present a hierarchical classification system for existing natural vegetation of Arkansas based on the United Nations Educational, Scientific and Cultural Organization (UNESCO) system. It incorporates aspects of systems in use by the Nature Conservancy, Arkansas Natural Heritage Commission, Arkansas Game and Fish Commission, Society of American Foresters, and United States Forest Service, as well as data on potential vegetation from maps by E.E. Dale and A.W. Kuchler. A total of 18 physiognomic cover types are recognized for natural terrestrial cover, 6 for palustrine cover, and 4 each for lacustrine cover and riverine cover. Over 200 community types are recognized, grouped into 57 cover types and 90 intermediate groupings. This system is appropriate for use with remotely sensed data and the level of detail dealt with can be rationally adjusted by working at a higher or lower level of the hierarchy. We suggest that this system form the basis for future vegetation analyses and research within Arkansas

Aging is associated with positive responding to neutral information but reduced recovery from negative information

Studies on aging and emotion suggest an increase in reported positive affect, a processing bias of positive over negative information, as well as increasingly adaptive regulation in response to negative events with advancing age. These findings imply that older individuals evaluate information differently, resulting in lowered reactivity to, and/or faster recovery from, negative information, while maintaining more positive responding to positive information. We examined this hypothesis in an ongoing study on Midlife in the US (MIDUS II) where emotional reactivity and recovery were assessed in a large number of respondents (N = 159) from a wide age range (36–84 years). We recorded eye-blink startle magnitudes and corrugator activity during and after the presentation of positive, neutral and negative pictures. The most robust age effect was found in response to neutral stimuli, where increasing age is associated with a decreased corrugator and eyeblink startle response to neutral stimuli. These data suggest that an age-related positivity effect does not essentially alter the response to emotion-laden information, but is reflected in a more positive interpretation of affectively ambiguous information. Furthermore, older women showed reduced corrugator recovery from negative pictures relative to the younger women and men, suggesting that an age-related prioritization of well-being is not necessarily reflected in adaptive regulation of negative affect

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV