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981.
Data visualization is aimed at obtaining a graphic representation of high dimensional information. A data projection over
a lower dimensional space is pursued, looking for some structure on the projections. Among the several data projection based
methods available, the Generative Topographic Mapping (GTM) has become an important probabilistic framework to model data.
The application to document data requires a change in the original (Gaussian) model in order to consider binary or multinomial
variables. There have been several modifications on GTM to consider this kind of data, but the resulting latent projections
are all scattered on the visualization plane. A document visualization method is proposed in this paper, based on a generative
probabilistic model consisting of a mixture of Zero-inflated Poisson distributions. The performance of the method is evaluated
in terms of cluster forming for the latent projections with an index based on Fisher’s classifier, and the topology preservation
capability is measured with the Sammon’s stress error. A comparison with the GTM implementation with Gaussian, multinomial
and Poisson distributions and with a Latent Dirichlet model is presented, observing a greater performance for the proposed
method. A graphic presentation of the projections is also provided, showing the advantage of the developed method in terms
of visualization and class separation. A detailed analysis of some documents projected on the latent representation showed
that most of the documents appearing away from the corresponding cluster could be identified as outliers. 相似文献
982.
Joachim Neumann Josep R. Casas Dušan Macho Javier Ruiz Hidalgo 《Personal and Ubiquitous Computing》2009,13(1):15-23
At the Technical University of Catalonia (UPC), a smart room has been equipped with 85 microphones and 8 cameras. This paper
describes the setup of the sensors, gives an overview of the underlying hardware and software infrastructure and indicates
possibilities for high- and low-level multi-modal interaction. An example of usage of the information collected from the distributed
sensor network is explained in detail: the system supports a group of students that have to solve a lab assignment related
problem.
This work has been partially supported by the European Union, IP 506909 (CHIL) 相似文献
983.
We evaluated the usefulness of different molecular techniques for the genetic analysis of Saccharomyces cerevisiae strains. Three commonly used PCR-derived genetic methods, random amplified polymorphic DNA (RAPDs), amplified fragment length polymorphism (AFLPs) and simple sequence repeats (SSRs; microsatellites), were used to characterize 27 wine yeast strains of S. cerevisiae from the “Denominación de Origen Vinos de Madrid” (Spain). Using these methods, we were able to overcome certain limitations associated with classical taxonomic methods. Based on the presence or absence of amplified fragments for each genotype, AFLPs and SSRs showed a similar discriminatory power superior to that of the RAPDs. Genetic relationships between strains were also estimated using the three methods. In general, very poor correlations were found, reflecting the different genomic regions for which the methods are screened. Results are discussed in terms of which molecular technique is most appropriate for use with a particular aspect of genetic evaluation. 相似文献
984.
985.
Glucagon is a peptide hormone that plays a central role in the maintenance of normal circulating glucose levels. Structure-activity studies have previously demonstrated the importance of histidine at position 1 and the absolute requirement for aspartic acid at position 9 for transduction of the hormonal signal. Site-directed mutagenesis of the receptor protein identified Asp64 on the extracellular N-terminal tail to be crucial for the recognition function of the receptor. In addition, antibodies generated against aspartic acid-rich epitopes from the extracellular region competed effectively with glucagon for receptor sites, which suggested that negative charges may line the putative glucagon binding pocket in the receptor. These observations led to the idea that positively charged residues on the hormone may act as counterions to these sites. Based on these initial findings, we synthesized glucagon analogs in which basic residues at positions 12, 17, and 18 were replaced with neutral or acidic residues to examine the effect of altering the positive charge on those sites on binding and adenylyl cyclase activity. The results indicate that unlike N-terminal histidine, Lys12, Arg17, and Arg18 of glucagon have very large effects on receptor binding and transduction of the hormonal signal, although they are not absolutely critical. They contribute strongly to the stabilization of the binding interaction with the glucagon receptor that leads to maximum biological potency. 相似文献
986.
AA Gaspari R Burns A Nasir D Ramirez RK Barth CG Haidaris 《Canadian Metallurgical Quarterly》1998,66(9):4440-4449
Transgenic (Tg) mice whose epidermal keratinocytes constitutively overexpress either B7-1 (CD80) or B7-2 (CD86) exhibited exaggerated cutaneous delayed type hypersensitivity (DTH) to haptens compared to non-Tg mice. To determine whether enhanced DTH in these Tg mice is seen in response to cutaneous fungal infections, a primary infection with Candida albicans was established by inoculating this organism on the occluded skin of Tg and non-Tg mice. These infections resolved 7 days after removal of occlusive dressing in all three groups of mice, without evidence of exaggerated inflammation in either the Tg or non-Tg mice. Only B7-2 Tg mice developed enhanced Th1-lymphocyte-mediated immune responses to C. albicans antigens after resolving this infection: enhanced footpad swelling in response to intradermal C. albicans antigens, enhanced production of mRNA encoding Th1 lymphokines in draining lymph nodes, and increased gamma interferon secreted into culture supernatants by lymph node T lymphocytes stimulated with Candida antigens in vitro. Lastly, Western blotting of sera from mice that had resolved this fungal infection indicated that only B7-2 Tg mice recognized a wide range of Candida-associated antigens. These data suggest that these two costimulatory molecules, when expressed by keratinocytes, do not deliver identical signals to C. albicans antigen-reactive Th1 lymphocytes. The enhanced immune response in B7-2 Tg mice to a cutaneous C. albicans infection demonstrates the importance of antigen presentation and costimulation in immune reactivity to fungi. Furthermore, B7-2 Tg mice may be useful in identification of protective Candida antigens. 相似文献
987.
An epitope of keratan sulphate (KS) and total glycosaminoglycans (GAG) were measured in synovial fluid samples from joints of 53 horses immediately following humane destruction. Internal examination of the joints post mortem ensured that there was no gross evidence of osteoarthritis or other joint disease. Joints sampled were distal interphalangeal (DIP), proximal interphalangeal (PIP), metacarpophalangeal (MCP), metatarsophalangeal (MTP), tarsometatarsal (TMT), tarsocrural (TC), femoropatellar (FP) and antebrachiocarpal (ABC) joints. The age of each horse was assessed by examination of the teeth. Samples were analysed for the KS epitope using a monoclonal antibody 5D4 and an inhibition ELISA and for total GAG level by a direct dye binding technique. There was no significant correlation between KS or GAG concentration and age. However, there were significant differences in the concentrations of KS and GAG in different joints. The median level (+semi interquartile range) of KS:GAG ratio in the MCP was significantly lower than the PIP (0.25 [0.05] vs. 0.35 [0.08]; P < 0.007) and also the DIP joints (0.25 [0.05] vs. 0.47 [0.09] P < 0.001). This study provides information which is both valuable in the investigation of normal joint metabolism and essential in the interpretation of synovial fluid KS and GAG values in their potential role as aids in the evaluation of joint disease. 相似文献
988.
YS Anderson NJ Curtis JA Hobbs CH Thompson CG Winearls GK Radda K Clarke P Altmann 《Canadian Metallurgical Quarterly》1997,12(5):981-983
BACKGROUND: As abnormally high serum D-lactate levels may cause neurological impairment, we determined whether patients undergoing continuous ambulatory peritoneal dialysis (CAPD) with lactate-containing fluids have increased serum D-lactate concentrations. METHODS: D- and L-lactate concentrations were determined in peritoneal dialysis fluids and in serum from control subjects (n = 10), haemodialysis patients (n = 10), and CAPD patients (n = 30) before and after 1 h of dialysis. RESULTS: We found the median D-lactate concentration in Dianeal CAPD fluid to be 26 mM (range 19-27), whereas it was less than 0.5 mM in DPCA2 fluid. Control, haemodialysis, and CAPD (DPCA2) patient median serum D-lactate concentrations were below 0.07 mM. However, CAPD (Dianeal) patient serum D-lactate concentrations were 4-fold higher than controls (P < 0.0001), at 0.28 mM, an hour after instillation of D-lactate-containing fluid. Three patients, whose serum D-lactate averaged 0.59 mM, were found to have D-lactate concentrations at 0.22 mM after overnight cessation of dialysis. CONCLUSION: We conclude that CAPD with D-lactate-containing fluids raises serum D-lactate to abnormal levels. 相似文献
989.
A Nana P Youngchaiyud N Maranetra J Boe CG L?fdahl O Selroos E St?hl 《Canadian Metallurgical Quarterly》1998,92(2):167-172
BACKGROUND: Stem-cell transplantation is a reasonable therapeutic approach for younger patients with high-risk CLL. PATIENTS AND METHODS: Twelve patients (seven males; median age 47 years, range 29-51) with high-risk CLL underwent transplantation (allo, n = 7; auto, n = 5). The conditioning regimen consisted of cyclophosphamide and total body irradiation in 11 patients, and BEAC in the remaining one. Minimal residual disease (MRD) was assessed by cytofluorometry and PCR. RESULTS: All 11 evaluable patients engrafted. Of the seven allografted patients, two died of treatment-related causes; three patients developed acute GVHD. No transplant-related mortality was observed in autografted patients. After transplantation, 10 of 11 patients evaluable for response achieved CR (91%; 95% CI 59%-100%) which was molecular in nine patients (82%; 95% CI 48%-98%). One patient in CR but MRD+ relapsed nine months after transplantation and died. Seven patients remain in molecular CR for a median of 16 months (range 1-58). Estimated actuarial survival and disease-free survival at two years is 81% (95% CI 43%-100%) and 71% (95% CI 43%-99%), respectively. Relapse risk at two years is 12.5% (95% CI 0%-35.5%). CONCLUSIONS: Patients with high-risk CLL can achieve long-lasting molecular CR after SCT. The role of transplants in CLL management deserves investigation in controlled trials. 相似文献
990.