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71.
A hybrid mapping of information science 总被引:1,自引:0,他引:1
Previous studies have shown that hybrid clustering methods that incorporate textual content and bibliometric information can
outperform clustering methods that use only one of these components. In this paper we apply a hybrid clustering method based
on Fisher’s inverse chisquare to integrate full-text with citations and to provide a mapping of the field of information science.
We quantitatively and qualitatively asses the added value of such an integrated analysis and we investigate whether the clustering
outcome is a better representation of the field by comparing with a text-only clustering and with another hybrid method based
on linear combination of distance matrices. Our data set consists of almost 1000 articles and notes published in the period
2002–2004 in 5 representative journals. The optimal number of clusters for the field is 5, determined by using a combination
of distance-based and stability-based methods. Term networks present the cognitive structure of the field and are complemented
by the most representative publications. Three large traditional sub-disciplines, particularly, information retrieval, bibliometrics/scientometrics,
and more social aspects, and two smaller clusters about patent analysis and webometrics, can be distinguished. 相似文献
72.
73.
Rivera FA Mendonça LG Lopes G Santos JE Perez RV Amstalden M Correa-Calderón A Chebel RC 《Reproduction (Cambridge, England)》2011,141(3):333-342
Fertility of lactating dairy cows is associated with reduced progesterone (P(4)) concentration compared with nonlactating animals. The objective of the current study was to determine whether P(4) during growth of the first follicular wave (FFW) affects embryo quality. Lactating Holstein cows at 33±3 days post partum were allocated to one of three treatments. Cows in the FFW and FFW with P(4) (FFWP) treatments started the superstimulation protocol on day 1 of the estrous cycle and second follicular wave (SFW) cows started the superstimulation protocol on estrous cycle day 7. Cows were superstimulated with 400 mg of NIH-FSH-P1 (FSH) given twice daily for 5 days, two prostaglandin F(2α) (PGF(2α)) injections given with the ninth and tenth injections of FSH, GNRH given 48 h after the first PGF(2α) injection, and timed insemination 12 and 24 h after the GNRH injection. Cows in the FFWP treatment received two intravaginal P(4) inserts during the superstimulation. Embryos were recovered 6.5 days after artificial insemination and excellent/good and fair embryos were frozen and transferred. Blood was sampled daily from estrous cycle day 0 until insemination from donor cows. During the superstimulation protocol, P(4) was (P<0.01) greatest for SFW cows followed by FFWP and FFW cows respectively. The percentage of embryos-oocytes from SFW and FFWP cows classified as excellent/good and fair embryos was (P=0.02) greater than those of FFW cows. Pregnancy per embryo transfer was not (P≥0.73) affected by embryo donor treatment. Reduced embryo quality of cows induced to ovulate the follicles from the first follicular wave is a consequence of reduced P(4) during follicle growth. 相似文献
74.
Andréia Tremarin Gláucia M. F. Aragão Beatriz C. M. Salomão Teresa R. S. Brandão Cristina L. M. Silva 《Food and Bioprocess Technology》2017,10(4):720-729
Byssochlamys fulva is an ascospore producer fungus known to be heat resistant and commonly found in fruit juices. This work aims at studying the influence of soluble solid content and storage temperature on the growth of B. fulva in apple juices. Agar-added apple juices, adjusted to different levels of soluble solids (12, 20, 25, 35, 45, 55, 70 °Bx) were artificially inoculated with B. fulva spores and incubated at different temperatures (10, 15, 20, 25, 30 °C). Microorganisms’ growth was assessed every day for a total of 3 months. A Gompertz-based model was used in experimental data fit for each soluble solid and temperature condition applied. Kinetic parameters were estimated by nonlinear regression procedures. The soluble solids and temperature effects were thereafter included in the primary Gompertz-based model. The predictive ability of this expression in terms of B. fulva growth was successfully proven for the range of conditions tested. 相似文献
75.
Glória Meyberg Nunes Costa Yuri Guerrieri Simão Kislansky Marcelo Embiruçu 《应用聚合物科学杂志》2013,130(3):2106-2117
In the production process of low‐density polyethylene (LDPE), an important step is the flash separation of monomers and other small molecules from the polymer produced. The process is carried out adiabatically in two stages. To improve the performance of thermodynamic models, it is very important to analyze the use of model binary interaction parameters (BIP) dependent on the phase characteristics for each phase (phase‐dependent BIP). In this work the PC‐SAFT (perturbed‐chain statistical associating fluid theory) equation of state (EOS) is applied to the flash simulation of LDPE industrial separators using eight different resins. The main numerical aspects are examined with emphasis on the optimization strategy for the EOS BIP that explicitly characterizes each phase involved separately. The results demonstrate good predictive behavior. As a result of improved and more consistent modeling, a new strategy for optimized operation can be envisaged for the sequence of separators. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2106–2117, 2013 相似文献
76.
77.
In bidding farewell to Prof. Dr.-Ing. Jens Weitkamp, we remember his many activities and his beneficial influence on the development of science, notably in the various fields of chemical technology and engineering. These activities include his engagement in support of the development of techniques dedicated to improvement of our understanding of the complex phenomenon of mass transfer in nanoporous materials, as both an ingenious scientist and a brilliant organizer and gifted leader of scientific alliances. The present contribution provides a brief introduction to the many facets of research in this field, with particular recognition of the most recent developments and Prof. Weitkamp's contributions. 相似文献
78.
Lisa Träger Jan Gläsel Marc Scherle Julian Hartmann Ulrich Nieken Bastian J. M. Etzold 《化学工程与技术》2020,43(9):1876-1883
In adsorption heat pumps, the properties of the porous adsorbent and the refrigerant determine the performance. Major parameters for this working pair are the total uptake of the adsorptive, its kinetics, and the heat transfer characteristics. In the technical application despite powdered adsorbents, thin consolidated layers of the adsorbent can be attractive and obtained by a binder-based approach but likely result in competing material properties. Thus, for a process optimization, the accessible parameter space and interdependencies have to be known and were deduced in this work for model porous carbons (carbide-derived carbons derived from TiC and ZrC) and methanol as well as the addition of different amounts of boron nitride, silver, and graphite as heat-conductive agents and the use of two binders. 相似文献
79.
80.
A K?nig V Krenn R Gillitzer J Gl?ckner E Janssen F Gohlke J Eulert HK Müller-Hermelink 《Canadian Metallurgical Quarterly》1997,17(4):159-168
Psoriatic arthritis is an inflammatory arthropathy that ultimately can lead to joint destruction. In this study, we investigated the immunophenotypes of the inflammatory cells and the expression of interleukin-8 (IL-8), which is the hallmark chemoattractant cytokine of psoriasis in synovial membranes from patients exhibiting active psoriatic synovitis (n = 9). The tissue samples were examined by immunohistochemistry, Western blot analysis and in situ hybridisation. The inflammatory infiltrate consisted predominantly of CD3+ T lymphocytes, with a higher proportion of CD4+ than CD8+ T lymphocytes in six cases. CD3+ T lymphocytes were focally distributed near small blood vessels and the enlarged synovial intima. CD1+ interdigitating reticulum cells were not detected. CD22+ B lymphocytes and plasma cells were found in small aggregates without KiM4+ follicular dendritic cells. KiM8+ macrophages were located in the synovial intima and were distributed in a diffuse pattern near the synovial lining cells. CD15+ neutrophil granulocytes were detected in four cases. They were preferentially located in the vicinity of blood vessels and the synovial intima. IL-8 was found at a high level in the synovial lining cells and to a lesser extent in cells located in the perivascular areas. Immunofluorescence double staining showed IL-8 to be expressed in KiM8+ multinucleated giant cells, KiM8+ macrophages and CD3+ T lymphocytes. IL-8 receptor A was demonstrated in the synovial lining and in macrophages and lymphocytes. IL-8 was detected by immunoblot analysis of the synovial tissue at 8.4 kD. Employing in situ hybridisation, IL-8 mRNA was strongly and preferentially expressed in the synovial intima, as well as in macrophages and lymphocytes. The immunophenotype of the psoriatic arthritis inflammatory cells shows great similarity to the inflammatory infiltrate found in the synovial tissue of patients with rheumatoid arthritis. The preferential expression of IL-8 and IL-8 mRNA in the enlarged synovial intima and in lymphocytes and macrophages suggests that IL-8 exerts its action through activated mononuclear cells and T lymphocytes. It seems to play a role in regulating leucocyte traffic into the enlarged synovial intima and may contribute to the aggressive synovitis of patients with psoriatic arthritis. 相似文献