New Variables Research Articles

Clinical and Electrocardiographic Predictors of Cardiac Resynchronization Therapy Response That Correlate with the 6 min Walking Test.

Background: Cardiac resynchronization therapy is an essential treatment for heart failure patients. Candidates typically have cardiomyopathy accompanied by delayed electrical activation in the left ventricular lateral wall, causing uncoordinated contractions and worsening heart failure. Heart failure severity can be assessed with functional tests: the cardiopulmonary test, which is a maximal exercise test, remains the gold standard, but the 6 min walk test has emerged as an easier, faster, and more comfortable alternative to be used by clinicians to adjust treatment protocols for cardiovascular and pulmonary conditions. Methods: This is a prospective observational study that included 69 patients from a single healthcare facility, and the purpose was to determine if the 6 min walk test results could be associated with changes in various electrocardiographic, clinical, functional, and demographic parameters. All the parameters and the 6 min walk distance were recorded at four key time moments: before the procedure and after 6, 9, and 12 months. The electrocardiographic parameters were obtained from the patients' electrocardiograms recorded in the four key moments and included variables such as QRS area, duration, percentage of biventricular pacing, and many others, while the functional variables included the monitored intraprocedural systolic blood pressure and the end-systolic left ventricular volume. We also aimed to check if clinical conditions such as diabetes and chronic kidney disease and demographic variables such as age or sex have any impact. Results and Conclusions: All this research was performed in order to identify which parameters hold a predictive value and can serve as future criteria for better patient selection and for defining a proper resynchronization outcome. The study shows that parameters such as diabetes and QRS duration have an impact over the 6 min walk distance. Also, newer variables such as the QRS area and the R/S ratio may represent a direction worth studying in order to predict the outcomes of cardiac resynchronization therapy.

Risk Factors and Prevalence of Hepatitis B and C in Badin City, Pakistan

Hepatitis is a global health concern, and its ever increasing prevalence in Pakistan has highlighted the need to study its epidemiology and develop preventative strategies. Objective: To determine the frequency and identify the risk factors associated with hepatitis virus infections B and C among the population of Badin city. Methods: Seven hundred sixty-seven people were tested for Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) using immunochromatographic methods. Additional testing was performed on blood samples from individuals who tested positive for hepatitis, and quantitative Polymerase Chain Reaction (PCR) was used to determine the viral load. Results: A total of 767 individuals had hepatitis. Among these, the research found that HCV was more common than HBV. However, men were more affected than women. Data on the exposure to risk factors for hepatitis B and C among the patients in our study are presented in Table 2 Of the 767 respondents, 473 (61.7%) were shaved from a barber/beauty parlour. Approximately 358 (46.7%) patients with hepatitis reused syringes. Drug addiction was observed in 66 (8.6%) patients. A history of blood transfusion was observed in 73 patients (9.5 %). Obstetrical procedures, ear pricks, and nose piercings were reported in 195 (68.1%), 245 (85.7%) and 240 (83.9%) female patients with hepatitis, respectively. Conclusions: Barbers, blood transfusions, and intravenous drug use are the most common risk factors for the spread of HBV and HCV are barbers, blood transfusions, and Intravenous Drug Use (IDUs), although newer variables, including piercings of the nose and ears and IDPs, also contribute

Euclidean self-dual gravity: Ashtekar variables without gauge fixing

Euclidean self-dual gravity: Ashtekar variables without gauge fixing

Revisiting loop quantum gravity with selfdual variables: classical theory

We review the classical formulation of general relativity as an SL(2,C) gauge theory in terms of Ashtekar’s self-dual variables and reality conditions for the spatial metric (first reality condition) and its evolution (second reality condition), and we add some new observations and results. We first explain in detail how a connection taking values in the Lie algebra of the complex Lorentz group yields two spin(3,1) connections, one self-dual and one anti-self-dual, without the need for a spin structure. We then demonstrate that the self-dual part of the complexified Palatini action in Ashtekar variables requires a holomorphic phase space description in order to obtain a non-degenerate symplectic structure. The holomorphic phase space does not allow for the implementation of the reality conditions as additional constraints, so they have to be taken care of ‘by hand’ during the quantisation. We also observe that, due to the action being complex, there is an overall complex phase that can be chosen at will. We then review the canonical formulation and the consequences of the implementation of the reality conditions. We pay close attention to the transformation behaviour of the various fields under (complex) basis changes, as well as to complex analytic properties of the relevant functions on phase space.

Revisiting loop quantum gravity with selfdual variables: Hilbert space and first reality condition

Abstract We consider the quantization of gravity as an SL(2,C) gauge theory in terms of Ashtekar's selfdual variables and reality conditions for the spatial metric (RCI) and its evolution (RCII). We start from a holomorphic phase space formulation. It is then natural to push for a quantization in terms of holomorphic wave functions. Thus we consider holomorphic cylindrical wave functions over SL(2,C) connections. 

We use an overall phase ambiguity of the complex selfdual action to obtain Poisson brackets that mirror those of the real theory. We then show that there is a representation of the corresponding canonical commutation relations the space of holomorphic cylindrical functions. We describe a class of cylindrically consistent measures that implements RCI. We show that spin networks with SU(2) intertwiners form a basis for gauge invariant states. They are still mutually orthogonal, but the normalisation is different than for the Ashtekar-Lewandowski measure for SU(2). 

We do not consider RCII in the present article. Work on RCII is ongoing and will be presented elsewhere.

A gravitationally induced decoherence model using Ashtekar variables

We consider the coupling of a scalar field to linearised gravity and derive a relativistic gravitationally induced decoherence model using Ashtekar variables. The model is formulated at the gauge invariant level using suitable geometrical clocks in the relational formalism, broadening existing gauge invariant formulations of decoherence models. For the construction of the Dirac observables we extend the known observable map by a kind of dual map where the role of clocks and constraints is interchanged. We also discuss a second choice of geometrical clocks existing in the ADM literature. Then we apply a reduced phase space quantisation on Fock space and derive the final master equation choosing a Gibbs state for the gravitational environment and using the projection operator technique. The resulting master equation is not automatically of Lindblad type, a starting point sometimes assumed for phenomenological models, but still involves a residual time dependence at the level of the effective operators in the master equation due to the form of the correlation functions that we express in terms of thermal Wightman functions. Furthermore, we discuss why in the model analysed here the application of a second Markov approximation in order to obtain a set of time independent effective system operators is less straightforward than in some of the quantum mechanical models.

A Coherent Approach towards Quantum Gravity

This paper typically focuses on the rescaling or equivocally a phase transition from the asymptotic approach of renormalizing the quantum gravity to a more granular approach of the loop quantum gravity (LQG) and then merging it with the Regge calculus for deriving the spin-(2) graviton as the basis of the unified theory. To construct a successful Ultraviolet (UV) completed theory via the fixed-point renormalization group flow equations (FRGE) results in an asymptotic safety approach of the quantum gravity (QG). From the loop-(2) onwards, the higher derivative divergence terms like the higher derivative curvatures, and quadratic divergences with higher derivative scalars make the momentum go to infinity which assaults a problem in renormalizing the QG. If the Einstein-Hilbert (E-H) action, which is the principle of least action is being computed, arising an equation of motion, and a localized path integral (or partition functions) is defined over a curved space, then that action is shown to be associated with the higher order dimension in a more compactified way, resulting in an infinite winding numbers being accompanied through the exponentiality coefficients of the partition integrals in the loop expansions of the second order term onwards, and based on that localization principle, the entire path integral got collapsed to isolated points or granules that if corresponds the aforesaid actions, results in negating the divergences’ with an implied bijections’ and reverse bijections’ of a diffeomorphism of a continuous differentiable functional domains. If those domains are being attributed to the spatial constraints, Hamiltonian constraints, and Master constraints then, through Ashtekar variables, it can be modestly shown that the behavior of quantum origin of asymptotic safety behavior is similar to the LQG granules of spin foam spacetime. Then, we will proceed with the triangulation of the “zoomed in” entangled-points that results in the inclusion of Regge poles via the quantum number (+2,-2,0) as the produced variables of the spin-(2) graviton and spin-(0) dilaton.

Dosimetric Variables and Clinical Correlation of Toxicities and Breast Cosmesis in Adjuvant Hypofractionated Whole Breast Irradiation Using Field in Field 3DCRT

<h3>Purpose/Objective(s)</h3> The objective of our study was to assess the change in breast cosmesis, Acute skin toxicity, Late Skin Toxicity, Late Subcutaneous Tissue Toxicity at different points of time in patients receiving adjuvant Hypofractionated Whole Breast Radiotherapy schedule (HF-WBRT) and to find out any existing relation with any other dosimetric variables responsible for their outcomes. <h3>Materials/Methods</h3> The START B protocol for dose fractionation was followed. The cosmetic outcome of the patients was assessed using the Harvard Breast Cosmesis Grading Scale. Similarly, Acute toxicities, Late skin toxicities, Late subcutaneous tissue toxicities were recorded using the RTOG/EORTC scoring scheme. Data was generated on the different volumes of tissue receiving 95%,102%,105% and 107% of the prescribed dose respectively. Further, all these volumes were divided into two subgroups – dose volumes within the Whole Breast PTV and dose volumes outside the Whole Breast PTV. Multivariate Analysis of variables were done. Bivariate Correlations of differences were performed and outcomes were analyzed using Spearman's rho correlation coefficient test. We also ran the Binary Logistic Regression Analysis test for predicting the outcomes of interest with the different variables. <h3>Results</h3> 125 patients were accrued and analyzed for this study. For acute skin toxicity, significant positive correlations existed with the volume of tissue within the PTV receiving 95% (0.695) and 102% (0.430) and with the volume of tissue outside the PTV receiving 95% (0.333) of the prescribed dose. The volume of tissue outside the PTV receiving 102% had a significant predictive probability for acute skin toxicity [p=0.001, OR 1.056 (1.024-1.029)]. For late skin toxicity, a significant positive correlation existed with the volume of tissue within the PTV receiving 95% (0.465). For late subcutaneous tissue toxicity, there was a significant positive correlation with the volume of tissue within the PTV receiving 95% (0.516). Significant predictive associations were found with the volume of tissue within the PTV receiving 105% [p=0.014, OR 1.014(1.003-1.026)] and volume of tissue outside the PTV receiving 102 % [p=0.00, OR 1.052(1.025-1.080)]. For a change in breast cosmesis, Significant predictive associations were found with volume of tissue within the PTV receiving 95% [p=0.00, OR 1.006(1.004-1.009)] and 102% [p=0.02, OR 1.003(1.001-1.005)]. <h3>Conclusion</h3> The volume of tissue receiving more than 105% was found to be a factor for the development of late toxicities The volume of tissue outside the breast PTV receiving more than 102% also should be kept at a minimum as it had a significant association with both changes in breast cosmesis and with acute and late toxicities. Therefore, newer variables like excess dose above the prescribed dose received by tissue, outside the PTV, also needs to be looked into. This study thus hypothesizes use of more conformal planning techniques in whole breast irradiation.

Dirac Observables in the 4-Dimensional Phase Space of Ashtekar’s Variables and Spherically Symmetric Loop Quantum Black Holes

In this paper, we study a proposal put forward recently by Bodendorfer, Mele and Münch and García-Quismondo and Marugán, in which the two polymerization parameters of spherically symmetric black hole spacetimes are the Dirac observables of the four-dimensional Ashtekar’s variables. In this model, black and white hole horizons in general exist and naturally divide the spacetime into the external and internal regions. In the external region, the spacetime can be made asymptotically flat by properly choosing the dependence of the two polymerization parameters on the Ashtekar variables. Then, we find that the asymptotical behavior of the spacetime is universal, and, to the leading order, the curvature invariants are independent of the mass parameter m. For example, the Kretschmann scalar approaches zero as K≃A0r−4 asymptotically, where A0 is generally a non-zero constant and independent of m, and r the geometric radius of the two-spheres. In the internal region, all the physical quantities are finite, and the Schwarzschild black hole singularity is replaced by a transition surface whose radius is always finite and non-zero. The quantum gravitational effects are negligible near the black hole horizon for very massive black holes. However, the behavior of the spacetime across the transition surface is significantly different from all loop quantum black holes studied so far. In particular, the location of the maximum amplitude of the curvature scalars is displaced from the transition surface and depends on m; so does the maximum amplitude. In addition, the radius of the white hole is much smaller than that of the black hole, and its exact value sensitively depends on m, too.

The Barbero–Immirzi Parameter: An Enigmatic Parameter of Loop Quantum Gravity

The Barbero–Immirzi parameter, (γ), is introduced in loop quantum gravity (LQG), whose physical significance is still the biggest open question because of its profound traits. In some cases, it is real valued, while it is complex valued in other cases. This parameter emerges in the process of denoting a Lorentz connection with a non-compact group SO(3,1) in the form of a complex connection with values in a compact group of rotations, either SO(3) or SU(2). Initially, it appeared in the Ashtekar variables. Fernando Barbero proposed its possibility for inclusion within formalism. Its present value is fixed by counting micro states in loop quantum gravity and matching with the semi-classical black hole entropy computed by Stephen Hawking. This parameter is used to count the size of the quantum of area in Planck units. Until the discovery of the spectrum of the area operator in LQG, its significance remained unknown. However, its complete physical significance is yet to be explored. In the present paper, an introduction to the Barbero–Immirzi parameter in LQG, a timeline of this research area, and various proposals regarding its physical significance are given.

The Effect of Store Atmosphere and Social Media Marketing on Purchase Decisions on Consumers of the Damandiri Cafe

This study aims to determine and analyze the influence of social media and store atmosphere on purchase intention at the Damandiri cafe in Selo, Boyolali Regency. This type of research is quantitative research using a conclusive classification: data collection techniques using non-probability sampling classification and judgmental techniques. The number of samples used in this study was as many as 100 respondents who knew and had accessed the Instagram account of Damandiri café. The analysis technique uses multiple linear regression analysis with the SPSS version 25 program. The results show that social media positively and significantly affect purchase intention at Damandiri cafe in Selo, Boyolali. There is a significant influence of the store atmosphere has a positive and significant effect on the purchase intention of a Damandiri café in Selo, Boyolali. Café Damandiri is expected to be able to design outlets in such a way as to increase customer convenience with a positive store atmosphere. In addition, it is expected to consider the social media to increase consumer purchase intention. Further research can use newer variables such as convenience, promotion, or service quality.

Loop quantum gravity with optimal control path integral, and application to black hole tunneling

This paper presents a novel path integral formalism for Einstein's theory of gravitation from the viewpoint of optimal control theory. Despite its close relation to the well-known variational principles of physicists, optimal control turns out to be more general. Within this context, a Lagrangian different from the Einstein-Hilbert Lagrangian is defined. Einstein field equations are recovered exactly with variations of the new action functional. The quantum theory is obtained using Ashtekar variables and the loop scalar product. By means of example, the tunneling process of a black hole into another black hole or into a white hole is investigated with a toy model.

Semiclassical and quantum features of the Bianchi I cosmology in the polymer representation

We analyze the Bianchi I cosmology in the presence of a massless scalar field and describe its dynamics via a semiclassical and quantum polymer approach by adopting three different sets of configurational variables: the natural Ashtekar connections, a set of anisotropic volumelike coordinates and the Universe volume plus two anisotropy coordinates (the latter two sets of variables would coincide in the case of an isotropic Universe). In the semiclassical analysis we demonstrate that the big bounce clearly emerges in all the sets of variables. Moreover, when adopting the proper volume variables (i.e. when defining the Universe volume itself on the polymer lattice) we also derive the exact polymer-modified Friedmann equation for the Bianchi I model. This way, the expression of the critical energy density that includes the anisotropic energylike contribution is obtained, demonstrating that in this set of variables the big bounce has a universal nature (i.e. its critical energy density has a maximum value fixed by fundamental constants and the Immirzi parameter). Finally, a proposal is made to recover the equivalence between the dynamics in the Ashtekar set and in the anisotropic volumelike one, showing that this request is satisfied when a polymer parameter depending on the configurational coordinates is considered. Then, we apply the Arnowitt-Deser-Misner reduction of the variational principle and we quantize the system. We study the resulting Schr\"odinger-like dynamics only in the Ashtekar variables and in the proper volume ones, stressing that the behavior of the Universe wave packet over time singles out common features with the semiclassical trajectories. However, we show that the standard deviation for the Universe volume operator grows with time. This is a signal of the spreading of the Bianchi I wave packet and hence of the importance of the quantum fluctuations in order to properly study the big bounce picture.

An Overview on the Nature of the Bounce in LQC and PQM

We present a review on some of the basic aspects concerning quantum cosmology in the presence of cut-off physics as it has emerged in the literature during the last fifteen years. We first analyze how the Wheeler–DeWitt equation describes the quantum Universe dynamics, when a pure metric approach is concerned, showing how, in general, the primordial singularity is not removed by the quantum effects. We then analyze the main implications of applying the loop quantum gravity prescriptions to the minisuperspace model, i.e., we discuss the basic features of the so-called loop quantum cosmology. For the isotropic Universe dynamics, we compare the original approach, dubbed the μ0 scheme, and the most commonly accepted formulation for which the area gap is taken as physically scaled, i.e., the so-called μ¯ scheme. Furthermore, some fundamental results concerning the Bianchi Universes are discussed, especially with respect to the morphology of the Bianchi IX model. Finally, we consider some relevant criticisms developed over the last ten years about the real link existing between the full theory of loop quantum gravity and its minisuperspace implementation, especially with respect to the preservation of the internal SU(2) symmetry. In the second part of the review, we consider the dynamics of the isotropic Universe and of the Bianchi models in the framework of polymer quantum mechanics. Throughout the paper, we focus on the effective semiclassical dynamics and study the full quantum theory only in some cases, such as the FLRW model and the Bianchi I model in the Ashtekar variables. We first address the polymerization in terms of the Ashtekar–Barbero–Immirzi connection and show how the resulting dynamics is isomorphic to the μ0 scheme of loop quantum cosmology with a critical energy density of the Universe that depends on the initial conditions of the dynamics. The following step is to analyze the polymerization of volume-like variables, both for the isotropic and Bianchi I models, and we see that if the Universe volume (the cubed scale factor) is one of the configurational variables, then the resulting dynamics is isomorphic to that one emerging in loop quantum cosmology for the μ¯ scheme, with the critical energy density value being fixed only by fundamental constants and the Immirzi parameter. Finally, we consider the polymer quantum dynamics of the homogeneous and inhomogeneous Mixmaster model by means of a metric approach. In particular, we compare the results obtained by using the volume variable, which leads to the emergence of a singularity- and chaos-free cosmology, to the use of the standard Misner variable. In the latter case, we deal with the surprising result of a cosmology that is still singular, and its chaotic properties depend on the ratio between the lattice steps for the isotropic and anisotropic variables. We conclude the review with some considerations of the problem of changing variables in the polymer representation of the minisuperspace dynamics. In particular, on a semiclassical level, we consider how the dynamics can be properly mapped in two different sets of variables (at the price of having to deal with a coordinate dependent lattice step), and we infer some possible implications on the equivalence of the μ0 and μ¯ scheme of loop quantum cosmology.

Pengaruh Media Sosial, Lokasi, Store Atmosphere terhadap Niat Beli di Cafe

This study aims to determine and analyze the influence of social media, location, store atmosphere on purchase intention at the friend's cafe in Sampang. This type of research is quantitative research using a conclusive classification: data collection techniques using non-probability sampling classification and judgmental techniques. The number of samples used in this study was as many as 100 respondents who knew and had accessed the Instagram account of Teman Sehati café. The analysis technique uses multiple linear regression analysis with the SPSS version 25 program. The results show that social media positively and significantly affect purchase intention at Teman Sehati cafe in Sampang. There is a significant influence of location on purchase intention at the Teman Sehati cafe Sampang; the store atmosphere has a positive and significant effect on the purchase intention of a Teman Sehati café in Sampang. Café Teman Sehati is expected to be able to design outlets in such a way as to increase customer convenience with a positive store atmosphere. In addition, it is expected to consider the location to increase consumer purchase intention. Further research can use newer variables such as convenience, promotion, or service quality.

The canonical formulation of E6(6) exceptional field theory

We investigate the canonical formulation of the (bosonic) E6(6) exceptional field theory. The explicit non-integral (not manifestly gauge invariant) topological term of E6(6) exceptional field theory is constructed and we consider the canonical formulation of a model theory based on the topological two-form kinetic term. Furthermore we construct the canonical momenta and the canonical Hamiltonian of the full bosonic E6(6) exceptional field theory. Most of the canonical gauge transformations and some parts of the canonical constraint algebra are calculated. Moreover we discuss how to translate the results canonically into the generalised vielbein formulation. We comment on the possible existence of generalised Ashtekar variables.

Concise symplectic formulation for tetrad gravity

We discuss a simple symplectic formulation for tetrad gravity that leads to the real Ashtekar variables in a direct and transparent way. It also sheds light on the role of the Immirzi parameter and the time gauge.

Prognostication and Determinants of Outcome in Adults and Children with Moderate-to-Severe Traumatic Brain Injury

It has been suggested in the literature that many physicians lack comfort in assessing prognosis following traumatic brain injury (TBI). The purpose of this review is to investigate the most recent work on predicting outcomes after moderate-to-severe TBI. TBI is one of the leading causes of disability in the USA with an estimated 13.5 million individuals affected by varying severities of TBI. Many clinical variables, including age, admission Glasgow Coma Scale score, duration of posttraumatic amnesia, and duration of coma, have been studied to determine whether they play a role in outcome prediction. Newer variables being studied include serum biomarkers, abnormalities observed on magnetic resonance imaging, and data obtained from evoked potentials. The role of physiatry in evaluating patients following moderate-to-severe TBI is a valuable but difficult proposition. Appropriate distribution of acute treatment and rehabilitation resources is of utmost importance. For prognostication to be clinically useful, physiatrists must provide a reasonable impression of what life will be like for the patient in the longer term. In the future, additional work will be needed to better combine predictor variables tailored with precision to the patient to provide a clearer picture of individual outcomes following moderate-to-severe TBI.

Revisiting da escala de avaliação do contexto de trabalho

A avaliação do contexto de trabalho de grandes populações pode proporcionar um diagnóstico de valor estratégico para organizações. Nesse contexto, este estudo propõe uma revisiting da escala de avaliação do contexto de trabalho (EACT) da Psicodinâmica do Trabalho, conforme modelo proposto por Mendes (2007). Como justificativa para o estudo, verificou-se a (i) necessidade de proceder com a Análise Fatorial Confirmatória (AFC) do instrumento; (ii) transformação das variáveis para o sentido positivo, bem como (iii) inclusão de uma nova variável na escala. Metodologicamente, receberam-se 202 respostas por meio da plataforma Google Forms, que foram sumarizadas para o software SPSS, versão 23. Por sua vez, o software AMOS, versão 20, foi utilizado na operacionalização da AFC. Os procedimentos metodológicos seguiram os moldes propostos por Costa (2011) para validação e mensuração de escalas. Os resultados demonstraram uma redução na quantidade de itens, bem como uma elevação no nível de confiabilidade em todos os fatores que compõem a escala. Por fim, sugere-se a inclusão de perguntas para a caracterização da amostra, bem como a aplicação do instrumento em diversos contextos para atestar sua adaptabilidade.

Generating functional for gravitational null initial data

A field theory on a three-dimensional manifold is introduced, whose field equations are the constraint equations for general relativity on a three-dimensional null hypersurface. The underlying boundary action consists of two copies of the dressed Chern–Simons term for self-dual Ashtekar variables, a kinetic term for the null flag at the boundary plus additional junction conditions for the spin coefficients across the interface. In fact, there is a doubling of the field content, because the null hypersurface is treated as an internal boundary between two adjacent slabs of spacetime. The paper concludes with a proposal for the construction of the gravitational transition amplitudes in the bulk via a gluing prescription for edge states across two-dimensional corners, thus providing a proposal for a quasi-local realisation of the holographic principle at the light front.