IMRT QA using machine learning: A multi-institutional validation.

PurposeTo validate a machine learning approach to Virtual intensity-modulated radiation therapy (IMRT) quality assurance (QA) for accurately predicting gamma passing rates using different measurement approaches at different institutions.MethodsA Virtual IMRT QA framework was previously developed using a machine learning algorithm based on 498 IMRT plans, in which QA measurements were performed using diode-array detectors and a 3%local/3 mm with 10% threshold at Institution 1. An independent set of 139 IMRT measurements from a different institution, Institution 2, with QA data based on portal dosimetry using the same gamma index, was used to test the mathematical framework. Only pixels with ≥10% of the maximum calibrated units (CU) or dose were included in the comparison. Plans were characterized by 90 different complexity metrics. A weighted poison regression with Lasso regularization was trained to predict passing rates using the complexity metrics as input.ResultsThe methodology predicted passing rates within 3% accuracy for all composite plans measured using diode-array detectors at Institution 1, and within 3.5% for 120 of 139 plans using portal dosimetry measurements performed on a per-beam basis at Institution 2. The remaining measurements (19) had large areas of low CU, where portal dosimetry has a larger disagreement with the calculated dose and as such, the failure was expected. These beams need further modeling in the treatment planning system to correct the under-response in low-dose regions. Important features selected by Lasso to predict gamma passing rates were as follows: complete irradiated area outline (CIAO), jaw position, fraction of MLC leafs with gaps smaller than 20 or 5 mm, fraction of area receiving less than 50% of the total CU, fraction of the area receiving dose from penumbra, weighted average irregularity factor, and duty cycle.ConclusionsWe have demonstrated that Virtual IMRT QA can predict passing rates using different measurement techniques and across multiple institutions. Prediction of QA passing rates can have profound implications on the current IMRT process

Limits on the use of cobalt sulfide as anode of p-type dye-sensitized solar cells

Thin films of cobalt sulfide (CoS) of thickness l < 10m have been employed as anodes of p-type dye-sensitized solar cells (p-DSCs) when P1-sensitized nickel oxide (NiO) was the photoactive cathode and /I - constituted the redox mediator. In the role of counter electrode for p-DSCs, CoS was preferred over traditional platinized fluorine-doped indium oxide (Pt-FTO) due to the lower cost of the starting materials (Co salts) and the easier procedure of deposition onto large area substrates. The latter process was carried out via direct precipitation of CoS from aqueous solutions. The photoconversion efficiency (η) of the corresponding device was 0.07%. This value is about 35% less than the efficiency that is obtained with the analogous p-DSC employing the Pt-FTO anode (η = 0.11). Unlike p-DSCs based on Pt-FTO anodes, the photoelectrochemical cells employing CoS electrodes showed that this anodic material was not able to sustain the photocurrent densities generated by P1-sensitized NiO at a given photopotential. Illumination of the p-DSCs with CoS anodes and P1-sensitized NiO cathodes actually induced the reverse bias of the photoelectrochemical cell with CoS behaving like a p-type semiconductor with no degeneracy. © 2017 IOP Publishing Ltd

Scaling behavior of quark propagator in full QCD

We study the scaling behavior of the quark propagator on two lattices with similar physical volume in Landau gauge with 2+1 flavors of dynamical quarks in order to test whether we are close to the continuum limit for these lattices. We use configurations generated with an improved staggered (``Asqtad'') action by the MILC collaboration. The calculations are performed on $28^3\times 96$ lattices with lattice spacing $a = 0.09$ fm and on $20^3\times 64$ lattices with lattice spacing $a = 0.12$ fm. We calculate the quark mass function, $M(q^2)$, and the wave-function renormalization function, $Z(q^2)$, for a variety of bare quark masses. Comparing the behavior of these functions on the two sets of lattices we find that both $Z(q^2)$ and $M(q^2)$ show little sensitivity to the ultraviolet cutoff.Comment: 6 pages, 5 figure

Factors Associated with Occupational Stress among Workers in The Production Department

Background: Occupational stress is one of the major health hazards of the modern workplace. Occupational stress and stressful working conditions have been linked to low productivity, absenteeism, and increased rates of accidents on and off the job. This study aimed to determine the factors associated with occupational stress among workers in the production department of a plant in Jakarta. Subjects and Method: This was a cross sectional study conducted at the production department of a plant, Jakarta. A sample of 72 workers was selected for this study. The dependent variable was occupational stress. The independent variables were noise, self-esteem, interpersonal conflict, uncertainty, job opportunity, physical burden, mental workload, and supervisor support. Occupational stress was measured by NIOSH generic job stress questionnaire. Noise was measured by sound level meter (Noise Pro Quest Model DLX). The other data was collected by questionnaire. The data were analyzed by a multiple logistic reg¬ression. Results: Occupational stress increased with low self-esteem (OR=6.43; 95% CI= 1.30 to 31.83), strong interpersonal conflict (OR= 2.03; 95% CI= 0.49 to 8.45), job uncertainty (OR= 1.30; 95% CI= 0.27 to 6.20), lack of job opportunity (OR= 6.65; 95% CI= 1.40 to 31.59), strong physical burden (OR= 9.64; 95% CI=1.96 to 47.46), high mental workload (OR= 12.82; 95% CI=2.21 to 74.32), and weak supervisor support (OR= 8.89; 95% CI= 1.7 to 42.22). Occupational stress decreased with low noise (OR=0.17; 95% CI= 0.04 to 0.77). Conclusion: Occupational stress increases with low self-esteem, strong inter-personal conflict, uncertainty, lack of job opportunity, strong physical burden, high mental workload, and weak supervisor support. It decreases with low noise. Keywords: occupational stress, risk factor, worke

Fermion Dynamics by Internal and Space-Time Symmetries

This manuscript is devoted to introduce a gauge theory of the Lorentz Group based on the ambiguity emerging in dealing with isometric diffeo-morphism-induced Lorentz transformations. The behaviors under local transformations of fermion fields and spin connections (assumed to be ordinary world vectors) are analyzed in flat space-time and the role of the torsion field, within the generalization to curved space-time, is briefly discussed. The fermion dynamics is then analyzed including the new gauge fields and assuming time-gauge. Stationary solutions of the problem are also analyzed in the non-relativistic limit, to study the spinor structure of an hydrogen-like atom.Comment: 10 pages, no figur

A model checking approach to the parameter estimation of biochemical pathways

Model checking has historically been an important tool to verify models of a wide variety of systems. Typically a model has to exhibit certain properties to be classed ‘acceptable’. In this work we use model checking in a new setting; parameter estimation. We characterise the desired behaviour of a model in a temporal logic property and alter the model to make it conform to the property (determined through model checking). We have implemented a computational system called MC2(GA) which pairs a model checker with a genetic algorithm. To drive parameter estimation, the fitness of set of parameters in a model is the inverse of the distance between its actual behaviour and the desired behaviour. The model checker used is the simulation-based Monte Carlo Model Checker for Probabilistic Linear-time Temporal Logic with numerical constraints, MC2(PLTLc). Numerical constraints as well as the overall probability of the behaviour expressed in temporal logic are used to minimise the behavioural distance. We define the theory underlying our parameter estimation approach in both the stochastic and continuous worlds. We apply our approach to biochemical systems and present an illustrative example where we estimate the kinetic rate constants in a continuous model of a signalling pathway

Management of late-preterm and term infants with hyperbilirubinaemia in resource-constrained settings.

Hyperbilirubinaemia is a ubiquitous transitional morbidity in the vast majority of newborns and a leading cause of hospitalisation in the first week of life worldwide. While timely and effective phototherapy and exchange transfusion are well proven treatments for severe neonatal hyperbilirubinaemia, inappropriate or ineffective treatment of hyperbilirubinaemia, at secondary and tertiary hospitals, still prevails in many poorly-resourced countries accounting for a disproportionately high burden of bilirubin-induced mortality and long-term morbidity. As part of the efforts to curtail the widely reported risks of frequent but avoidable bilirubin-induced neurologic dysfunction (acute bilirubin encephalopathy (ABE) and kernicterus) in low and middle-income countries (LMICs) with significant resource constraints, this article presents a practical framework for the management of late-preterm and term infants (≥ 35 weeks of gestation) with clinically significant hyperbilirubinaemia in these countries particularly where local practice guidelines are lacking. Standard and validated protocols were followed in adapting available evidence-based national guidelines on the management of hyperbilirubinaemia through a collaboration among clinicians and experts on newborn jaundice from different world regions. Tasks and resources required for the comprehensive management of infants with or at risk of severe hyperbilirubinaemia at all levels of healthcare delivery are proposed, covering primary prevention, early detection, diagnosis, monitoring, treatment, and follow-up. Additionally, actionable treatment or referral levels for phototherapy and exchange transfusion are proposed within the context of several confounding factors such as widespread exclusive breastfeeding, infections, blood group incompatibilities and G6PD deficiency, which place infants at high risk of severe hyperbilirubinaemia and bilirubin-induced neurologic dysfunction in LMICs, as well as the limited facilities for clinical investigations and inconsistent functionality of available phototherapy devices. The need to adjust these levels as appropriate depending on the available facilities in each clinical setting and the risk profile of the infant is emphasised with a view to avoiding over-treatment or under-treatment. These recommendations should serve as a valuable reference material for health workers, guide the development of contextually-relevant national guidelines in each LMIC, as well as facilitate effective advocacy and mobilisation of requisite resources for the optimal care of infants with hyperbilirubinaemia at all levels

Caracterização cromossômica de taxa do gênero Trinomys Thomas, 1921, (Rodentia, Echimyidae) nos Estados do Rio de Janeiro e São Paulo

Ten species of spiny rats of the genus Trinomys are currently recognized in eastern Brazil. Although most taxa known in the genus Trinomys have been characterized on the basis of craniodental, pelage, and bacular traits, data on chromosomal morphology are available for only four taxa, two from the State of Bahia, one from the State of São Paulo, and one from the State of Espírito Santo. Here we describe the normal chromosomal complement for three additional taxa, namely, Trinomys gratiosus bonafidei (Fazenda Boa Fé, Teresópolis, Rio de Janeiro, type-locality), Trinomys eliasi (Barra de Maricá, Maricá, Rio de Janeiro, type- locality), and Trinomys dimidiatus (Rio Bonito, Rio de Janeiro, and Ubatuba, São Paulo). The specimens analyzed here from the locality of Ubatuba were identified on the basis of craniodental, pelage, and bacular traits as T. dimidiatus, extending the known range of this species at least 100km south into the State of São Paulo. The three taxa for which chromosomal data are presented differ in their diploid and fundamental numbers and, therefore, can be diagnosed on the basis of their karyotypes. The significance and implications of chromosome numbers and morphology as diagnostic markers are evaluated in the framework of the molecular phylogenetic relationships and of the data on geographic distribution currently available for the genus Trinomys.Dez unidades taxonômicas no nível de espécie são atualmente reconhecidas para os roedores do gênero Trinomys no leste do Brasil. Embora a maioria dos taxa conhecidos tenham sido caracterizados com base em caracteres do crânio, da dentição, da pelagem e do báculo, a informação sobre a morfologia dos cromossomos limita-se até o momento apenas a quatro taxa, dois provenientes do Estado da Bahia, um de São Paulo e um do Espírito Santo. Neste trabalho são descritos os complementos cromossômicos para mais três taxa, Trinomys gratiosus bonafidei (Fazenda Boa Fé, Teresópolis, RJ, localidade tipo), Trinomys eliasi (Barra de Maricá, Maricá, RJ, localidade tipo) e Trinomys dimidiatus (Rio Bonito, RJ, and Ubatuba, SP). Os espécimes analisados neste estudo provenientes de Ubatuba foram identificados como T. dimidiatus com base em caracteres craniodentais, da pelagem e do báculo, estendendo a distribuição da espécie pelo menos 100km ao sul na direção do Estado de São Paulo. Os taxa analisados neste trabalho diferem nos seus números diplóide e fundamental e, por conseguinte, podem ser diagnosticados com base nos seus cariótipos. As implicações da variação nos cromossomos para a diagnose dos taxa do gênero Trinomys que ocorrem nos estados do Rio de Janeiro e São Paulo são avaliadas no contexto das relações filogenéticas deste grupo, inferidas a partir de seqüências do genoma mitocondrial e da informação disponível sobre a distribuição geográfica de suas espécies

Quench dynamics of the Kondo effect: transport across an impurity coupled to interacting wires

We study the real-time dynamics of the Kondo effect after a quantum quench in which a magnetic impurity is coupled to two metallic Hubbard chains. Using an effective field theory approach, we find that for noninteracting electrons the charge current across the impurity is given by a scaling function that involves the Kondo time. In the interacting case, we show that the Kondo time decreases with the strength of the repulsive interaction and the time dependence of the current reveals signatures of the Kondo effect in a Luttinger liquid. In addition, we verify that the relaxation of the impurity magnetization does not exhibit universal scaling behavior in the perturbative regime below the Kondo time. Our results highlight the role of nonequilibrium dynamics as a valuable tool in the study of quantum impurities in interacting systems