2,521 research outputs found
A universal approximate cross-validation criterion and its asymptotic distribution
A general framework is that the estimators of a distribution are obtained by
minimizing a function (the estimating function) and they are assessed through
another function (the assessment function). The estimating and assessment
functions generally estimate risks. A classical case is that both functions
estimate an information risk (specifically cross entropy); in that case Akaike
information criterion (AIC) is relevant. In more general cases, the assessment
risk can be estimated by leave-one-out crossvalidation. Since leave-one-out
crossvalidation is computationally very demanding, an approximation formula can
be very useful. A universal approximate crossvalidation criterion (UACV) for
the leave-one-out crossvalidation is given. This criterion can be adapted to
different types of estimators, including penalized likelihood and maximum a
posteriori estimators, and of assessment risk functions, including information
risk functions and continuous rank probability score (CRPS). This formula
reduces to Takeuchi information criterion (TIC) when cross entropy is the risk
for both estimation and assessment. The asymptotic distribution of UACV and of
a difference of UACV is given. UACV can be used for comparing estimators of the
distributions of ordered categorical data derived from threshold models and
models based on continuous approximations. A simulation study and an analysis
of real psychometric data are presented.Comment: 23 pages, 2 figure
The role of functional polymorphisms in immune response genes as biomarkers of BCG Immunotherapy outcome in bladder cancer: Establishment of a predictive profile in a Southern Europe population
OBJECTIVE:
To evaluate the predictive value of genetic polymorphisms in the context of BCG immunotherapy outcome and create a predictive profile that may allow discriminating the risk of recurrence.
MATERIAL AND METHODS:
In a dataset of 204 patients treated with BCG, we evaluate 42 genetic polymorphisms in 38 genes involved in the BCG mechanism of action, using Sequenom MassARRAY technology. Stepwise multivariate Cox Regression was used for data mining.
RESULTS:
In agreement with previous studies we observed that gender, age, tumor multiplicity and treatment scheme were associated with BCG failure. Using stepwise multivariate Cox Regression analysis we propose the first predictive profile of BCG immunotherapy outcome and a risk score based on polymorphisms in immune system molecules (SNPs in TNFA-1031T/C (rs1799964), IL2RA rs2104286 T/C, IL17A-197G/A (rs2275913), IL17RA-809A/G (rs4819554), IL18R1 rs3771171 T/C, ICAM1 K469E (rs5498), FASL-844T/C (rs763110) and TRAILR1-397T/G (rs79037040) in association with clinicopathological variables. This risk score allows the categorization of patients into risk groups: patients within the Low Risk group have a 90% chance of successful treatment, whereas patients in the High Risk group present 75% chance of recurrence after BCG treatment.
CONCLUSION:
We have established the first predictive score of BCG immunotherapy outcome combining clinicopathological characteristics and a panel of genetic polymorphisms. Further studies using an independent cohort are warranted. Moreover, the inclusion of other biomarkers may help to improve the proposed model
A transformative route to nanoporous manganese oxides of controlled oxidation states with identical textural properties
Nanoporous nanocrystalline metal oxides with tunable oxidation states are crucial for controlling their catalytic, electronic, and optical properties. However, previous approaches to modulate oxidation states in nanoporous metal oxides commonly lead to the breakdown of the nanoporous structure as well as involve concomitant changes in their morphology, pore size, surface area, and nanocrystalline size. Herein, we present a transformative route to nanoporous metal oxides with various oxidation states using manganese oxides as model systems. Thermal conversion of Mn-based metal-organic frameworks (Mn-MOFs) at controlled temperature and atmosphere yielded a series of nanoporous manganese oxides with continuously tuned oxidation states: MnO, Mn3O 4, Mn5O8, and Mn2O3. This transformation enabled the preparation of low-oxidation phase MnO and metastable intermediate phase Mn5O8 with nanoporous architectures, which were previously rarely accessible. Significantly, nanoporous MnO, Mn3O4, and Mn5O8 had a very similar morphology, surface area, and crystalline size. We investigated the electrocatalytic activity of nanoporous manganese oxides for oxygen reduction reaction (ORR) to identify the role of oxidation states, and observed oxidation state-dependent activity and kinetics for the ORR.close5
Limits on the Time Evolution of Space Dimensions from Newton's Constant
Limits are imposed upon the possible rate of change of extra spatial
dimensions in a decrumpling model Universe with time variable spatial
dimensions (TVSD) by considering the time variation of (1+3)-dimensional
Newton's constant. Previous studies on the time variation of (1+3)-dimensional
Newton's constant in TVSD theory had not been included the effects of the
volume of the extra dimensions and the effects of the surface area of the unit
sphere in D-space dimensions. Our main result is that the absolute value of the
present rate of change of spatial dimensions to be less than about
10^{-14}yr^{-1}. Our results would appear to provide a prima facie case for
ruling the TVSD model out. We show that based on observational bounds on the
present-day variation of Newton's constant, one would have to conclude that the
spatial dimension of the Universe when the Universe was at the Planck scale to
be less than or equal to 3.09. If the dimension of space when the Universe was
at the Planck scale is constrained to be fractional and very close to 3, then
the whole edifice of TVSD model loses credibility.Comment: 22 pages, accepted for publication in Int.J.Mod.Phys.
Past, present and future of information and knowledge sharing in the construction industry: Towards semantic service-based e-construction
The paper reviews product data technology initiatives in the construction sector and provides a synthesis of related ICT industry needs. A comparison between (a) the data centric characteristics of Product Data Technology (PDT) and (b) ontology with a focus on semantics, is given, highlighting the pros and cons of each approach. The paper advocates the migration from data-centric application integration to ontology-based business process support, and proposes inter-enterprise collaboration architectures and frameworks based on semantic services, underpinned by ontology-based knowledge structures. The paper discusses the main reasons behind the low industry take up of product data technology, and proposes a preliminary roadmap for the wide industry diffusion of the proposed approach. In this respect, the paper stresses the value of adopting alliance-based modes of operation
An iterative agent bidding mechanism for responsive manufacturing
In today's market, the global competition has put manufacturing businesses in great pressures to respond rapidly to dynamic variations in demand patterns across products and changing product mixes. To achieve substantial responsiveness, the manufacturing activities associated with production planning and control must be integrated dynamically, efficiently and cost-effectively. This paper presents an iterative agent bidding mechanism, which performs dynamic integration of process planning and production scheduling to generate optimised process plans and schedules in response to dynamic changes in the market and production environment. The iterative bidding procedure is carried out based on currency-like metrics in which all operations (e.g. machining processes) to be performed are assigned with virtual currency values, and resource agents bid for the operations if the costs incurred for performing them are lower than the currency values. The currency values are adjusted iteratively and resource agents re-bid for the operations based on the new set of currency values until the total production cost is minimised. A simulated annealing optimisation technique is employed to optimise the currency values iteratively. The feasibility of the proposed methodology has been validated using a test case and results obtained have proven the method outperforming non-agent-based methods
On exact solutions for quintessential (inflationary) cosmological models with exponential potentials
We first study dark energy models with a minimally-coupled scalar field and
exponential potentials, admitting exact solutions for the cosmological
equations: actually, it turns out that for this class of potentials the
Einstein field equations exhibit alternative Lagrangians, and are completely
integrable and separable (i.e. it is possible to integrate the system
analytically, at least by quadratures). We analyze such solutions, especially
discussing when they are compatible with a late time quintessential expansion
of the universe. As a further issue, we discuss how such quintessential scalar
fields can be connected to the inflationary phase, building up, for this class
of potentials, a quintessential inflationary scenario: actually, it turns out
that the transition from inflation toward late-time exponential quintessential
tail admits a kination period, which is an indispensable ingredient of this
kind of theoretical models. All such considerations have also been done by
including radiation into the model.Comment: Revtex4, 10 figure
FRA2A is a CGG repeat expansion associated with silencing of AFF3
Folate-sensitive fragile sites (FSFS) are a rare cytogenetically visible subset of dynamic mutations. Of the eight molecularly characterized FSFS, four are associated with intellectual disability (ID). Cytogenetic expression results from CGG tri-nucleotide-repeat expansion mutation associated with local CpG hypermethylation and transcriptional silencing. The best studied is the FRAXA site in the FMR1 gene, where large expansions cause fragile X syndrome, the most common inherited ID syndrome. Here we studied three families with FRA2A expression at 2q11 associated with a wide spectrum of neurodevelopmental phenotypes. We identified a polymorphic CGG repeat in a conserved, brain-active alternative promoter of the AFF3 gene, an autosomal homolog of the X-linked AFF2/FMR2 gene: Expansion of the AFF2 CGG repeat causes FRAXE ID. We found that FRA2A-expressing individuals have mosaic expansions of the AFF3 CGG repeat in the range of several hundred repeat units. Moreover, bisulfite sequencing and pyrosequencing both suggest AFF3 promoter hypermethylation. cSNP-analysis demonstrates monoallelic expression of the AFF3 gene in FRA2A carriers thus predicting that FRA2A expression results in functional haploinsufficiency for AFF3 at least in a subset of tissues. By whole-mount in situ hybridization the mouse AFF3 ortholog shows strong regional expression in the developing brain, somites and limb buds in 9.5-12.5dpc mouse embryos. Our data suggest that there may be an association between FRA2A and a delay in the acquisition of motor and language skills in the families studied here. However, additional cases are required to firmly establish a causal relationship
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