A second order cone formulation of continuous CTA model

The final publication is available at link.springer.comIn this paper we consider a minimum distance Controlled Tabular Adjustment (CTA) model for statistical disclosure limitation (control) of tabular data. The goal of the CTA model is to find the closest safe table to some original tabular data set that contains sensitive information. The measure of closeness is usually measured using l1 or l2 norm; with each measure having its advantages and disadvantages. Recently, in [4] a regularization of the l1 -CTA using Pseudo-Huber func- tion was introduced in an attempt to combine positive characteristics of both l1 -CTA and l2 -CTA. All three models can be solved using appro- priate versions of Interior-Point Methods (IPM). It is known that IPM in general works better on well structured problems such as conic op- timization problems, thus, reformulation of these CTA models as conic optimization problem may be advantageous. We present reformulation of Pseudo-Huber-CTA, and l1 -CTA as Second-Order Cone (SOC) op- timization problems and test the validity of the approach on the small example of two-dimensional tabular data set.Peer ReviewedPostprint (author's final draft

Experimental study of formwork tightness as a function of rheological properties of SCC

Several studies relating formwork pressure to rheology exist, however the relationship between rheology and leakage through formwork joints remains to be investigated. In practice, standard documents are used to define formwork tightness requirements, typically using a qualitative approach. To try bridge this gap in knowledge, we developed a test set-up to study tightness of formwork joints under pressure as a function of varying rheological properties. Coupled with standard rheology tests, this new test set-up provides means of linking flow rate, formwork pressure, flow area, and the rheological properties. The study seeks to provide insight on measurable governing parameters and thus inform formwork tightness requirements in a more quantifiable manner. This paper presents a test set-up designed to study the flow of fresh paste through small openings. It highlights a preliminary study on the pressure-driven flow of limestone paste through a bottom orifice in a cylindrical container. While this new device may not be directly representative of the actual conditions in formwork, it provides a good base for a fundamental study that can then be extrapolated to a more representative test operation. Preliminary results show a linear relationship between the flow rate and the applied pressure. The results also show that increasing the flow area by a factor of 2.33 had a higher impact than an increase in yield stress and viscosity by a factor of 2.54 and 3.80 respectively. However, more tests need to be carried out to obtain clear trends

Contractile effects of Ghrelin and expression of its receptor GHS-R1a in normal and hypertrophic myocardium

INTRODUCTION:Ghrelin, isolated in 1999, is an endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a). Recent studies suggest that it may influence the function of normal and failing hearts. Nonetheless, it has been difficult to differentiate its effects on the intrinsic properties of the myocardium from the secondary effects resulting from growth hormone release and vasomotor action. This study investigated the contractile effects of ghrelin and expression of its receptor GHS-R1a in normal and hypertrophic myocardium.METHODS:Adult Wistar rats randomly received monocrotaline (MCT; n=9; 60 mg/kg, s.c.) or vehicle (n=7; 1 ml/kg). Three weeks later, after right ventricular (RV) hemodynamic evaluation, the effects of 10(-6) M of a pentapeptide active fragment of ghrelin (fG) were tested on contractile parameters of RV papillary muscles (Normal, n=7; MCT, n=9). GHS-R1a mRNA expression was estimated in RV transmural free-wall samples (Normal, n=7; MCT, n=9), using real-time RT-PCR.RESULTS:In the Normal group, fG reduced active tension (AT), maximum velocity of tension rise (dT/dt(max)) and maximum velocity of tension decline (dT/dt(min)), by 27.9 +/- 4.0%, 28.5 +/- 6.7% and 21.4 +/- 4.2% respectively. In the MCT group, fG reduced AT, dT/dt(max) and dT/dt(min) by 24.1 +/- 6.3%, 24.3 +/- 6.5% and 24.5 +/- 6.1% respectively. GHS-R1a mRNA expression was similar in the two groups (Normal: 2.3*10(5) +/- 5.4*10(4); MCT: 3.0*10(5) +/- 1.1*10(5): p > 0.05).CONCLUSION:This study shows that ghrelin has negative inotropic and lusitropic effects. These effects and expression of its receptor are preserved in RV hypertrophy, suggesting that ghrelin may be a new target in progression to heart failure

Reframing landscape fragmentation's effects on ecosystem services.

REVIEWLandscape structure and fragmentation have important effects on ecosystem services, with a common assumption being that fragmentation reduces service provision. This is based on fragmentation's expected effects on ecosystem service supply, but ignores how fragmentation influences the flow of services to people. Here we develop a new conceptual framework that explicitly considers the links between landscape fragmentation, the supply of services, and the flow of services to people. We argue that fragmentation's effects on ecosystem service flow can be positive or negative, and use our framework to construct testable hypotheses about the effects of fragmentation on final ecosystem service provision. Empirical efforts to apply and test this framework are critical to improving landscape management for multiple ecosystem services.Australian Research Council Discovery ProjectAustralian Research Council's Centre of Excellence for Environmental DecisionsNERCChile Ministry of EducationCSIRO Integrative Natural Resource Management postgraduate fellowshipsCOLCIENCIA

Mutational mechanism for DAB1 (ATTTC) n insertion in SCA37: ATTTT repeat lengthening and nucleotide substitution

Dynamic mutations by microsatellite instability are the molecular basis of a growing number of neuromuscular and neurodegenerative diseases. Repetitive stretches in the human genome may drive pathogenicity, either by expansion above a given threshold, or by insertion of abnormal tracts in nonpathogenic polymorphic repetitive regions, as is the case in spinocerebellar ataxia type 37 (SCA37). We have recently established that this neurodegenerative disease is caused by an (ATTTC)n insertion within an (ATTTT)n in a noncoding region of DAB1. We now investigated the mutational mechanism that originated the (ATTTC)n insertion within an ancestral (ATTTT)n . Approximately 3% of nonpathogenic (ATTTT)n alleles are interspersed by AT-rich motifs, contrarily to mutant alleles that are composed of pure (ATTTT)n and (ATTTC)n stretches. Haplotype studies in unaffected chromosomes suggested that the primary mutational mechanism, leading to the (ATTTC)n insertion, was likely one or more T>C substitutions in an (ATTTT)n pure allele of approximately 200 repeats. Then, the (ATTTC)n expanded in size, originating a deleterious allele in DAB1 that leads to SCA37. This is likely the mutational mechanism in three similar (TTTCA)n insertions responsible for familial myoclonic epilepsy. Because (ATTTT)n tracts are frequent in the human genome, many loci could be at risk for this mutational process.We are grateful to the families and individuals who participated in this work. We thank Patricia Ribeiro for technical assistance. This study was financed by Fundo Europeu de Desenvolvimento Regional (FEDER), through the COMPETE 2020 Operational Pro- gram for Competitiveness and Internationalization (POCI) of Portugal 2020, and by the Fundacão para a Ciência e a Tecnologia (FCT) and Ministério da Ciência, Tecnologia e Ensino Superior (Portugal), in the framework of the project POCI-01-0145-FEDER-029255; (PTDC/MED-GEN/29255/2017) to I.S. J.R.L. and C.L.O. were sup- ported by scholarships from PEst-C/SAU/LA0002/2013. S.M. is funded by the project IF/00930/2013/ CP1184/CT0002 from FCT. This work was also funded by the Porto Neurosciences and Neurologic Disease Research Initiative at the Instituto de Investigação e Inovação em Saúde (Norte-01-0145-FEDER- 000008), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTU- GAL 2020 Partnership Agreement with FEDER

Immunophenotypic characterization of patients with American cutaneous leishmaniasis prior to and after treatment in Pernambuco, Brazil

Leishmania infections induce a specific activation of host immunological response, particularly characterized by T cell expansion. Studies indicate the importance of the balance between CD4+ and CD8+ T cells, in which the first ones would have their number reduced during the healing process. Meanwhile, CD25+ T cells have been associated with the suppression of the immune response. Since the immune response has an essential role in both healing and progression of diseases, this study aimed to identify the percentage of CD3+, CD4+, CD8+, CD16+ and CD25+ T cells in the peripheral blood of patients afflicted with American cutaneous leishmaniasis (ACL) - before and after treatment - and healthy controls. Peripheral blood was collected and transferred to cytometry tubes containing monoclonal antibodies specific for cell surface markers CD3, CD4, CD8, CD16 e CD25. The immunophenotypic and morphometric parameters of cells were determined by flow cytometry and the results demonstrated a significant increase in the number of T CD8+ cells after treatment, suggesting a cytotoxic T cell response. An increase in CD25+ T cells in patients with active ACL and after treatment was also observed, suggesting the participation of these cells in the modulation of the exacerbated effector response

Intervertebral disc classification by its degree of degeneration from T2-weighted magnetic resonance images

Purpose: The primary goal of this article is to achieve an automatic and objective method to compute the Pfirrmann’s degeneration grade of intervertebral discs (IVD) from MRI. This grading system is used in the diagnosis and management of patients with low back pain (LBP). In addition, biomechanical models, which are employed to assess the treatment on patients with LBP, require this grading value to compute proper material properties. Materials and methods: T2-weighted MR images of 48 patients were employed in this work. The 240 lumbar IVDs were divided into a training set (140) and a testing set (100). Three experts manually classified the whole set of IVDs using the Pfirrmann’s grading system and the ground truth was selected as the most voted value among them. The developed method employs active contour models to delineate the boundaries of the IVD. Subsequently, the classification is achieved using a trained Neural Network (NN) with eight designed features that contain shape and intensity information of the IVDs. Results: The classification method was evaluated using the testing set, resulting in a mean specificity (95.5 %) and sensitivity (87.3 %) comparable to those of every expert with respect to the ground truth. Conclusions: Our results show that the automatic method and humans perform equally well in terms of the classification accuracy. However, human annotations have inherent inter- and intra-observer variabilities, which lead to inconsistent assessments. In contrast, the proposed automatic method is objective, being only dependent on the input MRI

Mixture of Probabilistic Principal Component Analyzers for Shapes from Point Sets

Inferring a probability density function (pdf) for shape from a population of point sets is a challenging problem. The lack of point-to-point correspondences and the non-linearity of the shape spaces undermine the linear models. Methods based on manifolds model the shape variations naturally, however, statistics are often limited to a single geodesic mean and an arbitrary number of variation modes. We relax the manifold assumption and consider a piece-wise linear form, implementing a mixture of distinctive shape classes. The pdf for point sets is defined hierarchically, modeling a mixture of Probabilistic Principal Component Analyzers (PPCA) in higher dimension. A Variational Bayesian approach is designed for unsupervised learning of the posteriors of point set labels, local variation modes, and point correspondences. By maximizing the model evidence, the numbers of clusters, modes of variations, and points on the mean models are automatically selected. Using the predictive distribution, we project a test shape to the spaces spanned by the local PPCA's. The method is applied to point sets from: i) synthetic data, ii) healthy versus pathological heart morphologies, and iii) lumbar vertebrae. The proposed method selects models with expected numbers of clusters and variation modes, achieving lower generalization-specificity errors compared to state-of-the-art

Negative inotropic effect of selective AT(2) receptor stimulation and its modulation by the endocardial endothelium

Angiotensin II is an octapeptide whose effects are mediated by two types of receptors. AT, receptors are responsible for the vasoconstrictor, positive inotropic and growth promoting properties, while AT(2) receptors have been linked to vasodilator and anti-mitogenic properties. In this study we investigated the effects of selective AT, receptor stimulation on myocardial contractility and lusitropy. Effects of selective AT2 receptor activation were evaluated in rabbit right papillary muscles (n=96) by adding increasing concentrations of H-9395, an AT(2) receptor agonist, alone or in presence of a selective AT, receptor antagonist (ZD-7155), or alternatively, by adding increasing concentrations of angiotensin 11 in presence of ZD-7155. In the latter conditions, selective AT2 receptor activation was also performed in presence of NG-nitro-L-Arginine, indomethacin, proadifen, hydroxocobalamin, apamin plus charybdotoxin, Hoe-140 or PD-123,319, as well as, after endocardial endothelium removal. Selective AT2 stimulation induced a negative inotropic and lusitropic effect in the first three protocols. This effect was completely abolished after selective removal of the endocardial endothelium and blunted in presence of Hoe-140, hydroxocobalamin, apamin plus charybdotoxin and PD-123,319, but maintained in presence of NG-nitro-L-Arginine, indomethacin or proadifen. Selective AT(2) receptor stimulation induces a negative inotropic and lusitropic effect, which is modulated by endocardial endothelium, and mediated by bradykinin B, receptors through NO release and calcium dependent potassium channels activation. Such findings may help to better understand the therapeutic effects of selective AT, antagonists, which are increasingly used for treating cardiovascular diseases. (C) 2007 Published by Elsevier B.V