117,557 research outputs found
The rotational spectrum up to 1 THz and the molecular structure of thiomethylium, HCS
No full textThe rotational spectra of HCS+, DCS+, and (HCS+)-S-34 have been investigated using a newly constructed ion cell in selected regions between 0.46 and 0.94 THz. 23 transitions covering the quantum numbers 10 less than or equal to J" less than or equal to 25 have been used in a combined fit together with previous data to improve the rotational and quartic centrifigal distortion constants B-0 and D-0, respectively. High J transitions have been measured specifically to obtain an estimate of the sextic distortion constant H-0. Vibration rotation coupling constants alpha(i) were obtained from coupled cluster calculations. They were used to determine a mixed experimental/ab initio equilibrium structure r(e)
Searching for new populations of rare plant species in remote locations
No full text[Extract] Limited resources often do not permit biologists to conduct extensive searches for every species listed as rare or threatened or to undertake surveys over large areas to determine species locations (Nicholls 1989; Margules and Austin 1994; Wessels et a1. 1998). Further, it is inefficient
to depend upon "accidental discoveries" (Good and Lavarack 1981) to estimate species distributions. A more systematic and structured approach is needed. One such approach, the method detailed in this chapter, is to stratify the region of interest using environmental variables, note strata where populations of rare species are known, and search for new populations in similar environments in the same gene ral location and in the same environments at different geographic locations. In this way limited resources of labor, time, and funds can be used efficiently.
This approach is analogous to the way experienced field botanists would deal with the problem of searching for new populations of rare species. They create mental models of suitable habitat or environments and then look in the places those models suggest. We propose a systematic and explicit formalization of those models to make more available the sort of knowledge involved in constructing them. Using two plant species from Cape York Peninsula in northern Australia as case studies, this chapter details a protocol for searching for new populations of rare plants and explains how to use a systematic sampling approach to determine whether a species is truly rare or whether it is perceived to be rare as a result of inadequate sampling
Garnet-biotite geothermometry revised: New Margules parameters and a natural specimen data set from Maine
No full textThe garnet-biotite geothermometer has been recalibrated using recently obtained Margules parameters for iron-magnesium-calcium garnet. Mn interactions in garnet, and Al interactions in biotite, as well as the Fe oxidation state of both minerals. Fe-Mg and ΔWAl Margules parameters for biotite have been retrieved by combining experimental results on [6]Al-free and [6]Al-bearing biotite using statistical methods. Margules parameters, per mole of biotite are WB4MgFe = 40719 - 30T J/mole, ΔWB4Al = WB4FeAl - WB4MgAl = 210190 - 245.40T J/mole, ΔWB4Ti = WB4FeTi - WB4MgTi = 310990 - 370.39T J/mole. Based on this model, the exchange reaction ΔH is 41952 J/mol and ΔS is 10.35 J/(K mol). Estimated uncertainty for this geothermometer is 25 °C. This geothermometer was tested on two data sets. The first consisted of 98 specimens containing garnet and biotite from west-central Maine, which formed under reducing fo2 with graphite, a limited range of P (∼3 to 4.5 kbar), and a moderate range in T (∼550-650 °C), and which were all analyzed on a single microprobe using the same standards. Results indicate that the Maine staurolite zone averages 574 °C compared with 530 °C previously calculated and that the muscovite-breakdown T is consistent with experimental data. The second set consisted of cordierite-garnet granulites without hypersthene from Ontario. Results here suggest an average T of 662 °C, compared with significantly lower or higher Ts calculated from other geothermometers. This model reproduces the Perchuk and Lavrent\u27eva (1983) experimental Ts with a standard deviation of 12 °C and discriminates the assemblages in the Maine data set better than other models
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Submillimeter and Far-infrared Spectroscopy of Monodeuterated Amidogen Radical (NHD): Improved Rest Frequencies for Astrophysical Observations
No full textObservations of ammonia in interstellar environments have revealed high levels of deuteration, and all its D-containing variants, including ND3, have been detected in cold prestellar cores and around young protostars. The observation of these deuterated isotopologues is very useful for elucidating the chemical and physical processes taking place during the very early stages of star formation, as the abundance of deuterated molecules is highly enhanced in dense and cold gas. Nitrogen hydride radicals are key species lying at the very beginning of the reaction pathway leading to the formation of NH3 and organic molecules of prebiotic interest, but relatively little is known about their D-bearing isotopologues. To date, only ND has been detected in interstellar gas. To aid the identification of further deuterated nitrogen radicals, we have thoroughly reinvestigated the rotational spectrum of NHD by employing two different instruments: a frequency-modulation submillimeter spectrometer operating in the THz region and a synchrotron-based Fourier-transform infrared spectrometer operating in the 50-240 cm-1 frequency range. NHD was produced in a plasma of NH3 and D2. A wide range of rotational energy levels have been probed thanks to the observation of high-N (up to 15) and high-K a (up to 9) transitions. A global analysis including our new data and data from the literature has provided a comprehensive set of very accurate spectroscopic parameters. A highly reliable line catalog has been generated to assist archival data searches and future astronomical observations of NHD at submillimeter and THz regimes
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
- …
