177,368 research outputs found
Spectroscopy and crystal chemical properties of NaCa2[Si4O10]F natural agrellite with tubular structure
No full textAgrellite is a rare inosilicate, having a crystal structure characterized by SiO4-tetrahedral tubes located between continuous wall layers formed by edge-sharing Ca-polyhedra. A detailed crystal chemical and physical study of agrellite specimens is carried out by means of electron probe microanalysis, Fourier transform infrared spectroscopy, electron-paramagnetic resonance, and single crystal X-ray diffraction. Additionally, the electronic structures of agrellite was calculated. Luminescence due to 5d-4f transition in Ce3+ ions is observed in both investigated samples. EPR analysis points out the Mn2+ replaces Ca2+ ion in Ca(1A) and Ca(2B) positions, coordinated by two F sites
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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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
EFFICIECY OF AGRARIAN ORGANISATIONS
No full textThe goal of this paper is to incorporate achievements of the New Institutional and Transaction Costs Economics to analysis of efficiency of agrarian organizations in transitional economies. That modern framework for analysis of agrarian organizations is based on their role to govern transactions between individual agents. Since governing (coordination, organization) of transactions is associated with significant costs (for finding best prices and partners, for negotiation and contracting, for monitoring and enforcement of contract terms, for adjustment and re-negotiation according to changed conditions of exchange, for dispute resolutions etc.), the economic efficiency of agrarian organizations has to assess not only their capacity to minimize the production costs, but their potential to economize transacting costs as well. Initially, main kinds of transactions of the managers of agrarian transactions (farms entrepreneurs) are clarified as land, labor, service, inputs, and finance supply; marketing; and collective actions. After that, the alternative market, non-market, and mixed modes for organization of different types of agrarian transitions are identified. Next, various types of costs associated with each form of transacting are determined. And then, the comparative efficiency of different governance structures is estimated according to (minimum) transacting costs criteria. One direction for evaluation of comparative efficiency of governing structures is based on direct assessment of items of costs for transaction in different organizations. However, that manner is often restricted since: difficulties (or impossibility) to measure absolute level of transaction costs; opposite dynamics of different items of costs in various organizations; great use of complex (and interlinked) rather than pure modes in transitional agriculture; and not existence (missing) of alternative form for organization (the base for comparison). Another direction is through comparative structural (qualitative) analysis of alternative governing forms. Firstly, critical factors of transactions in particular institutional environment are identified. These factors affect transaction costs variation, and they are associated: with behavioral characteristic of agrarian agents (bounded rationality, tendency for opportunism, building of reputation, risk aversion, level of trusts); and with economic dimensions of individual transactions (frequency, uncertainty, assets specificity and appropriability). Secondly, assessment is made on effective potential of alternative organizational modes to: minimize bounded rationality of agrarian agents and uncertainty associated with transacting; to appropriate and protect private investments from possible opportunism; to recover long-term investments for organizational development through high recurrence of transactions between same agents; to exploit economy of size and scale on specific for relationship with a particular partner capital etc. Third, principal matrix of generic organizational modes is build for effective governance of transactions with different combination of critical dimensions: free market mode if effective to carry out transactions with high appropriability and low assets specificity; the special contract form is appropriate for transactions with high frequency, and increased uncertainty and assets specificity; the internal integration can manage effectively repeated transactions with high capital dependency and big uncertainty; the hybrid and public modes are the most effective forms for occasional transactions with low appropriability and high assets specificity. Finally, effective horizontal and vertical boundaries of every specific form within each generic modes could be determined through comparison of their potential to explore economy of size (scale) on specific or (and) specialized assets, and their comparative efficiency to minimize bounded rationality and to control opportunism of counterparts.agrarian governance, efficiency of agrarian organizations, new institutional and transaction costs economics
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Improvement of the crystal structural model of tinaksite
No full textTinaksite from ultralkaline agpaitic Murun massif (Russia) has been
investigated. The name reflects its composition: titanium (Ti), sodium
(Na), potassium (K) and silicon (Si). Its structure was reported for the
first time in 1971 by Petrunina [1]. To the best of author's knowledge,
tinaksite is the only silicate based on {hB, 21 }[3Si6O17(SiO2)] hybrid
anion [2]. The structural model of Tinaksite proposed by Petrunina [1]
was validated and improved by von Bissert [3] in 1980, who observed a
more regular tetrahedra conformation. The tinaksite investigated by von
Bissert [3] is triclinic with chemical composition: NaK2Ca2Ti[3Si7O19]OH. The
compound here investigated has chemistry more complex, ((Na0.855K1.993Ca
2.008Ti0.792Mg0.083Fe3+0.096Mn0.100Zr0.027Sr0.013Zr0.027Zn0.008Ni0.007Cr0.005)[3Si7O19]OH),
compared with Petrunina's [1] and von Bissert's [3] ones. It has been
refined in P1, using the following lattice parameters: a = 7.0565(1) Å, b =
10.3750(1) Å, c = 12.1885(2) Å, = 92.802(1)°, = 90.763(1)°, =
99.241(1)°.
In this work, the cation partition derived from SCXRD and EPMA data, is
presented. The structure has been anisotropically refined up to an R(F) =
0.025 (for 5238 observed reflections with Fo > (Fo)). Tinaksite exhibits
straight channels parallel to [001] direction, formed by double chains of
silicate. The channels are stretched approximately along [110] direction,
with maximum dimension 10.972(2) Å.
The highest peak in the Fourier difference map is related to some
structural disorder inside the Ti octahedron. This disorder likely can be
ascribed to the entrance of the large K substituting the six-fold
coordinated Na atom. As a matter of fact, the replacing of Na for K
changes the coordination number of the polyhedron from 6 to 7, which
seems to influence the neighbouring Ti atom position.
Another point concerns the K1 and K2 atoms located inside the channels.
According to von Bissert [3], the higher K1 thermal parameter with
respect to the K2 one indicates the site filled by K1 is disorder. The structural refinement shows that K1 atom is located over at least three
different positions. A charge distribution analysis, performed by means of
the Chardi-It software [4], has returned an ECON number [5] of 11 and 9
for the K1 and K2, respectively. The bond distances for the three K atoms,
related to K1, show these atoms are not always bonded to the same
oxygens. Indeed, K1 can move inside a cage formed by 14 oxygen atoms
with a volume of about 90 Å3. This volume results to be much larger even
than the one of the ideal twelve-fold coordinated K atom (~18 Å3)
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
Refinement of the Crystal Structure of Vlasovite from Burpala Massif (Russia)
No full textThe structural model and chemical composition of vlasovite from the Burpala massif (Russia) have been determined using X-ray diffraction methods and electron probe microanalysis. The crystal structure has been refined in the sp. gr. Cc to R = 1.4% (R w = 1.8%) with the following unit-cell parameters: a = 11.0396(3) Å, b = 10.1042(2) Å, c = 8.5696(2) Å, β = 100.307(1)°, V = 940.48(4) Å 3 , and Z = 4
- …
