919 resultados para Naive Bayes classifier
Resumo:
CCN3, a founding member of the CCN family of growth regulators, was linked with hematology in 2003(1) when it was detected in human serum. CCN3 is expressed and secreted by hematopoietic progenitor cells in normal bone marrow. CCN3 acts through the core stem cell signalling pathways including Notch and Bone Morphogenic Protein, connecting CCN3 with the modulation of self-renewal and maturation of a number of cell lineages including hematopoietic, osteogenic and chondrogenic. CCN3 expression is disrupted in Chronic Myeloid Leukemia as a consequence of the BCR-ABL oncogene and allows the leukemic clone to evade growth regulation. In contrast, naive cord blood progenitors undergo enhanced clonal expansion in response to CCN3. Altered CCN3 expression is associated with numerous solid tumors including glioblastoma, melanoma. adrenocortical tumours, prostate cancer and bone malignancies including osteosarcoma. Mature CCN3 protein has five distinct modules and truncated protein variants with altered function are found in many cancers. Regulation by CCN3 is therefore cell type and isoform specific. CCN3 has emerged as a key player in stem cell regulation, hematopoiesis and a crucial component within the bone marrow microenvironment. (c) 2008 Elsevier Ltd. All rights reserved.
Resumo:
Flutter prediction as currently practiced is usually deterministic, with a single structural model used to represent an aircraft. By using interval analysis to take into account structural variability, recent work has demonstrated that small changes in the structure can lead to very large changes in the altitude at which
utter occurs (Marques, Badcock, et al., J. Aircraft, 2010). In this follow-up work we examine the same phenomenon using probabilistic collocation (PC), an uncertainty quantification technique which can eficiently propagate multivariate stochastic input through a simulation code,
in this case an eigenvalue-based fluid-structure stability code. The resulting analysis predicts the consequences of an uncertain structure on incidence of
utter in probabilistic terms { information that could be useful in planning
flight-tests and assessing the risk of structural failure. The uncertainty in
utter altitude is confirmed to be substantial. Assuming that the structural uncertainty represents a epistemic uncertainty regarding the
structure, it may be reduced with the availability of additional information { for example aeroelastic response data from a flight-test. Such data is used to update the structural uncertainty using Bayes' theorem. The consequent
utter uncertainty is significantly reduced across the entire Mach number range.
Resumo:
Going against both the naive techno-optimist of ‘greening business as usual’ and a resurgent ‘catastrophism’ within green thinking and politics, The Politics of Actually Existing Unsustainability offers an analysis of the causes of unsustainability and diminished human flourishing. The books locates the causes of unsustainability in dominant capitalist modes of production, debt-based consumer culture, the imperative for orthodox economic growth and the dominant ideology of neoclassical economics. It suggests that valuable insights into the causes of and alternatives to unsustainability can be found in a critical embracing of human vulnerability and dependency as both constitutive and ineliminable aspects of what it means to be human. The book defends resilience, the ability to ‘cope with’ rather than somehow ‘solve’ vulnerability. The book offers a trenchant critique of the dominant neoclassical economic ‘groupthink’, viewing it not as some value-neutral form of ‘expert knowledge’, but as a thoroughly ideological ‘common sense’. Outlining a green political economic alternative replacing economic growth with economic security, it argues economic growth has done its work in the minority, affluent world, which should now focus on improving human flourishing, lowering socio-economic equality and fostering solidarity as part of a new re-orientation of public policy. Complementing this, a, ‘green republicanism’ is developed as an innovative and original contribution to contemporary debates on a ‘post-growth’ economy and society. The Politics of Actually Existing Unsustainability draws widely from a range of disciplines and thinkers, from cultural critic Susan Sontag to the critical theory of the Frankfurt School, contemporary debates in green political thinking, and the latest thinking in heterodox and green economics, to produce a highly relevant, timely, and provocatively original statement on the human predicament in the twenty-first century.
Resumo:
Nearly all psychological research on basic cognitive processes of category formation and reasoning uses sample populations associated with large research institutions in technologically-advanced societies. Lopsided attention to a select participant pool risks biasing interpretation, no matter how large the sample or how statistically reliable the results. The experiments in this article address this limitation. Earlier research with urban-USA children suggests that biological concepts are (1) thoroughly enmeshed with their notions of naive psychology, and (2) strikingly human-centered. Thus, if children are to develop a causally appropriate model of biology, in which humans are seen as simply one animal among many, they must undergo fundamental conceptual change. Such change supposedly occurs between 7 and 10 years of age, when the human-centered view is discarded. The experiments reported here with Yukatek Maya speakers challenge the empirical generality and theoretical importance of these claims. Part 1 shows that young Maya children do not anthropocentrically interpret the biological world. The anthropocentric bias of American children appears to owe to a lack of cultural familiarity with non-human biological kinds, not to initial causal understanding of folkbiology as such. Part 2 shows that by age of 4-5 (the earliest age tested in this regard) Yukatek Maya children employ a concept of innate species potential or underlying essence much as urban American children seem to, namely, as an inferential framework for understanding the affiliation of an organism to a biological species, and for projecting known and unknown biological properties to organisms in the face of uncertainty. Together, these experiments indicate that folkpsychology cannot be the initial source of folkbiology. They also underscore the possibility of a species-wide and domain-specific basis for acquiring knowledge about the living world that is constrained and modified but not caused or created by prior nonbiological thinking and subsequent cultural experience.
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We here describe novel aspects of CD8(+) and CD4(+) T cell subset interactions that may be clinically relevant and provide new tools for regulating the reconstitution of the peripheral CD8(+) T cell pools in immune-deficient states. We show that the reconstitution capacity of transferred isolated naive CD8(+) T cells and their differentiation of effector functions is limited, but both dramatically increase upon the co-transfer of CD4(+) T cells. This helper effect is complex and determined by multiple factors. It was directly correlated to the number of helper cells, required the continuous presence of the CD4(+) T cells, dependent on host antigen-presenting cells (APCs) expressing CD40 and on the formation of CD4/CD8/APC cell clusters. By comparing the recovery of (CD44(+)CD62L(high)) T-CM and (CD44(+)CD62L(low)) T-EM CD8(+) T cells, we found that the accumulation of TCM and TEM subsets is differentially regulated. T-CM-cell accumulation depended mainly on type I interferons, interleukin (IL)-6, and IL-15, but was independent of CD4(+) T-cell help. In contrast, TEM-cell expansion was mainly determined by CD4(+) T-cell help and dependent on the expression of IL-2R beta by CD8 cells, on IL-2 produced by CD4(+) T-cells, on IL-15 and to a minor extent on IL-6.
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Although the use of olfactory cues in pigeon navigation is well established, the generality of olfactory navigation remains uncertain because of apparent variability in results gained by different researchers in different regions. We report the results of the first experiments investigating the effect of anosmia on homing pigeons reared in a previously uninvestigated region, southern England. In series 1, experienced birds showed little effect of anosmia induced with zinc sulphate at unfamiliar sites 30 km and 39 km from the loft, but treated birds were significantly poorer than controls at homing from an unfamiliar site 66 km distant (and in pooled results). In series 2, naive (untrained) birds, both control and zinc-sulphate-treated, showed poor homing abilities and initial orientation from sites 25 km, 36 km and 39 km from the loft. Nevertheless, in pooled results, controls showed significantly better homeward orientation than anosmic birds and were significantly more likely to home on the day of release. The most likely explanation for our results is that pigeons are able to use olfactory navigation in southern England, but that for some reason the olfactory map is relatively weak.
Resumo:
Excretory secretory products (ESP) of Schistosoma mansoni developing larvae are ideal potential vaccines as such molecules may readily induce host primary immune responses, and local memory immune response effectors that would target, surround, and pursue the larvae while negotiating the lung blood capillaries. We herein characterized the cytokines response ESP, e.g., SG3PDH, 14-3-3-like protein, TPX, and calpain induce in the natural context of infection, and defined the global cytokine profile conducive to effective schistosome larvae killing. Accordingly, spleen cells (SC) taken from naive, and 7-, or 9-day S. mansoni-infected mice were stimulated in vitro with the selected ESP, in a recombinant or multiple antigen peptide (MAP) form, and examined for production of T helper type (Th) 1, Th2, and Th17 cytokines, and the ability to mediate in vitro attrition of lung-stage schistosomula. The study indicated that larval ESP principally elicit Th1 and Th17 type cytokines. Recombinant SG3PDH was the only test ESP to additionally activate SC from S. mansoni-infected BALB/c mice to release higher IL-4 levels than unstimulated SC and mediate significant (P
Resumo:
Computational research with continuous representations depends on obtaining continuous representations from human labellers. The main method used for that purpose is tracing. Tracing raises a range of challenging issues, both psychological and statistical. Naive assumptions about these issues are easy to make, and can lead to inappropriate requirements and uses. The natural function of traces is to capture perceived affect, and as such they belong in long traditions of research on both perception and emotion. Experiments on several types of material provide information about their characteristics, particularly the ratings on which people tend to agree. Disagreement is not necessarily a problem in the technique. It may correctly show that people’s impressions of emotion diverge more than commonly thought. A new system, Gtrace, is designed to let rating studies capitalise on a decade of experience and address the research questions that are opened up by the data now available.
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Discrete Conditional Phase-type (DC-Ph) models are a family of models which represent skewed survival data conditioned on specific inter-related discrete variables. The survival data is modeled using a Coxian phase-type distribution which is associated with the inter-related variables using a range of possible data mining approaches such as Bayesian networks (BNs), the Naïve Bayes Classification method and classification regression trees. This paper utilizes the Discrete Conditional Phase-type model (DC-Ph) to explore the modeling of patient waiting times in an Accident and Emergency Department of a UK hospital. The resulting DC-Ph model takes on the form of the Coxian phase-type distribution conditioned on the outcome of a logistic regression model.
Resumo:
We address the problem of non-linearity in 2D Shape modelling of a particular articulated object: the human body. This issue is partially resolved by applying a different Point Distribution Model (PDM) depending on the viewpoint. The remaining non-linearity is solved by using Gaussian Mixture Models (GMM). A dynamic-based clustering is proposed and carried out in the Pose Eigenspace. A fundamental question when clustering is to determine the optimal number of clusters. From our point of view, the main aspect to be evaluated is the mean gaussianity. This partitioning is then used to fit a GMM to each one of the view-based PDM, derived from a database of Silhouettes and Skeletons. Dynamic correspondences are then obtained between gaussian models of the 4 mixtures. Finally, we compare this approach with other two methods we previously developed to cope with non-linearity: Nearest Neighbor (NN) Classifier and Independent Component Analysis (ICA).
Resumo:
In this paper we propose a statistical model for detection and tracking of human silhouette and the corresponding 3D skeletal structure in gait sequences. We follow a point distribution model (PDM) approach using a Principal Component Analysis (PCA). The problem of non-lineal PCA is partially resolved by applying a different PDM depending of pose estimation; frontal, lateral and diagonal, estimated by Fisher's linear discriminant. Additionally, the fitting is carried out by selecting the closest allowable shape from the training set by means of a nearest neighbor classifier. To improve the performance of the model we develop a human gait analysis to take into account temporal dynamic to track the human body. The incorporation of temporal constraints on the model increase reliability and robustness.
Resumo:
Chronic lung infection by opportunistic pathogens, such as Pseudomonas aeruginosa and members of the Burkholderia cepacia complex, is a major cause of morbidity and mortality in patients with cystic fibrosis. Outer membrane proteins (OMPs) of gram-negative bacteria are promising vaccine antigen candidates. In this study, we evaluated the immunogenicity, protection, and cross-protection conferred by intranasal vaccination of mice with OMPs from B. multivorans plus the mucosal adjuvant adamantylamide dipeptide (AdDP). Robust mucosal and systemic immune responses were stimulated by vaccination of naive animals with OMPs from B. multivorans and B. cenocepacia plus AdDP. Using a mouse model of chronic pulmonary infection, we observed enhanced clearance of B. multivorans from the lungs of vaccinated animals, which correlated with OMP-specific secretory immunoglobulin A responses. Furthermore, OMP-immunized mice showed rapid resolution of the pulmonary infection with virtually no lung pathology after bacterial challenge with B. multivorans. In addition, we demonstrated that administration of B. multivorans OMP vaccine conferred protection against B. cenocepacia challenge in this mouse infection model, suggesting that OMPs provide cross-protection against the B. cepacia complex. Therefore, we concluded that mucosal immunity to B. multivorans elicited by intranasal vaccination with OMPs plus AdDP could prevent early steps of colonization and infection with B. multivorans and also ameliorate lung tissue damage, while eliciting cross-protection against B. cenocepacia. These results support the notion that therapies leading to increased mucosal immunity in the airways may help patients with cystic fibrosis.
Resumo:
BACKGROUND: The mitotic arrest deficiency protein 2 (MAD2) is a key component of the mitotic spindle assembly checkpoint, monitoring accurate chromosomal alignment at the metaphase plate before mitosis. MAD2 also has a function in cellular senescence and in a cell’s response to microtubule inhibitory (MI) chemotherapy exemplified by paclitaxel.
METHODS: Using an siRNA approach, the impact of MAD2 down-regulation on cellular senescence and paclitaxel responsiveness was investigated. The endpoints of senescence, cell viability, migration, cytokine expression, cell cycle analysis and anaphase bridge scoring were carried out using standard approaches.
RESULTS: We show that MAD2 down-regulation induces premature senescence in the MCF7 breast epithelial cancer cell line. These MAD2-depleted (MAD2k) cells are also significantly replicative incompetent but retain viability. Moreover, they show significantly higher levels of anaphase bridges and polyploidy compared to controls. In addition, these cells secrete higher levels of IL-6 and IL-8
representing key components of the senescence-associated secretory phenotype (SASP) with the ability to impact on neighbouring cells. In support of this, MAD2kcells show enhanced migratory ability. At 72 h after paclitaxel, MAD2kcells show a significant further induction of senescence compared with paclitaxel naive controls. In addition, there are significantly more viable cells in the MAD2k MCF7 cell line after paclitaxel reflecting the observed increase in senescence.
CONCLUSION: Considering that paclitaxel targets actively dividing cells, these senescent cells will evade cytotoxic kill. In conclusion, compromised MAD2 levels induce a population of senescent cells resistant to paclitaxel.
Resumo:
Support vector machines (SVMs), though accurate, are not preferred in applications requiring high classification speed or when deployed in systems of limited computational resources, due to the large number of support vectors involved in the model. To overcome this problem we have devised a primal SVM method with the following properties: (1) it solves for the SVM representation without the need to invoke the representer theorem, (2) forward and backward selections are combined to approach the final globally optimal solution, and (3) a criterion is introduced for identification of support vectors leading to a much reduced support vector set. In addition to introducing this method the paper analyzes the complexity of the algorithm and presents test results on three public benchmark problems and a human activity recognition application. These applications demonstrate the effectiveness and efficiency of the proposed algorithm.
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