A Lie algebra attached to a projective variety

Each choice of a K\"ahler class on a compact complex manifold defines an action of the Lie algebra \slt on its total complex cohomology. If a nonempty set of such K\"ahler classes is given, then we prove that the corresponding \slt-copies generate a semisimple Lie algebra. We investigate the formal properties of the resulting representation and we work things out explicitly in the case of complex tori, hyperk\"ahler manifolds and flag varieties. We pay special attention to the cases where this leads to a Jordan algebra structure or a graded Frobenius algebra.Comment: AMSTeX v2.1, 46 page

A Lie algebra attached to a projective variety

Each choice of a K\"ahler class on a compact complex manifold defines an action of the Lie algebra \slt on its total complex cohomology. If a nonempty set of such K\"ahler classes is given, then we prove that the corresponding \slt-copies generate a semisimple Lie algebra. We investigate the formal properties of the resulting representation and we work things out explicitly in the case of complex tori, hyperk\"ahler manifolds and flag varieties. We pay special attention to the cases where this leads to a Jordan algebra structure or a graded Frobenius algebra.Comment: AMSTeX v2.1, 46 page

The Use of Dry Cupping with Active Movement to Increase Functional Mobility and Decrease Pain in a Patient with Cervical Disc Disorder: A Case Report

Background: Cervical disc disorders are very common in today’s population and many physical therapists treat these patients daily with varying interventions, including soft tissue massage, manipulations, stretches and exercises. Another potential intervention is dry cupping, which is a technique that decreases fascial tension under the skin and allows increased blood flow to the area, to promote muscle healing. The purpose of this case study is to describe the successful use of dry cupping with active movement as part of the physical therapy treatment of a patient with cervical disc disorder. Case Description: The patient was a 41 year old female who came to physical therapy via direct access due to prolonged bilateral neck pain that extended down her left ribs to her left hip. She also had a long standing history of C4-C5 radiculopathy. The patient presented with decreased and painful cervical range of motion and strength, as well as cervical and upper thoracic hypomobility. Intervention: The patient was seen 2 times per week for 10 weeks. The final 6 weeks of treatment included one session each week of cupping with active movement. The dry cupping treatment included 4-5 cups on both the left and right trapezius, rhomboids, and supraspinatus muscles depending on palpation of musculature and restrictions in movement each session. The patient then completed several movements with the cups on her skin. Outcome Measures: The outcome measures used were the Upper Extremity Quick-Dash, pain scale, self rated functional improvement, as well as active range of motion measured with goniometry and manual muscle testing. Discussion: This case report supports the use of dry cupping with active movement as an intervention to decrease cervical pain and dysfunction in patients with cervical disc disorders, without adverse side effects

Continuum Robotic Surface: Forward Kinematic Analysis and Implementation

This thesis presents a new class of biologically inspired robots: continuum robotic surfaces. This work is fueled by the question: can the interaction between robot and environment be advanced with “programmable surfaces in space?” The novelty of continuum robotic surfaces lies in their ability to be actively controlled and reconfigured in what we believe is the current “missing dimension” in robot movements — two–dimensional space. We believe that such surfaces will lend themselves to more complex applications. However, to effectively deploy such surfaces for these complex applications, kinematic models will be necessary to plan and control desired configurations. The forward kinematic models for continuum surfaces introduced herein are an initial step in achieving this goal. Then, to test the precision of our model, we validate it via hardware realizations. Lastly, with the kinematic model and hardware realization, the next step is to explore one of the aforementioned complex applications for these surfaces. We believe that a continuum robotic surface can lend itself to upper–extremity stroke rehabilitation in a novel way. Our efforts in interactively designing and building a working prototype with the clinical and staff healthcare subject matter experts at the Roger C. Peace Rehabilitation Center of the Greenville Hospital System are detailed

Computability Theory

Computability is one of the fundamental notions of mathematics, trying to capture the effective content of mathematics. Starting from Gödel’s Incompleteness Theorem, it has now blossomed into a rich area with strong connections with other areas of mathematical logic as well as algebra and theoretical computer science

Obstetric Violence in Spain (Part II): Interventionism and Medicalization during Birth

This article belongs to the Special Issue Obstetric Violence and Women's HealthBackground: obstetric violence can partially be represented by the high number of interventions and medicalization rates during the birthing process. The objective of the present study was to determine the interventionism and medicalization levels during childbirth in Spain. Methods: a descriptive, retrospective, and cross-sectional study was conducted between January 2018 and June 2019. Results: the intervention percentages were 34.2% for Kristeller maneuver and 39.3% for episiotomy. Differences appeared in public, private, and mixed healthcare settings (p < 0.001). The mean satisfaction, with healthcare in the different settings, was estimated at 6.88 points (SD ± 2.146) in public healthcare, 4.76 points (SD ± 3.968) in private healthcare, and 8.03 points (SD ± 1.930) in mixed healthcare (p < 0.001). No statistically significant differences were found in Spanish autonomous communities. Conclusions: births in Spain seem to be highly intervened. In this study, a certain equity criterion was found concerning interventionism during childbirth in Spain. Healthcare influenced female intervention, satisfaction, and perception levels for obstetric violence; this evidences that female empowerment plays an important role

New reconstruction strategies for polyenergetic X-ray computer tomography

Mención Internacional en el título de doctorX-ray computed tomography (CT) provides a 3D representation of the attenuation coefficients of patient tissues, which are roughly decreasing functions of energy in the usual range of energies used in clinical and preclinical scenarios (from 30 KeV to 150 KeV). Commercial scanners use polychromatic sources, producing a beam having a range of photon energies, because no X-ray lasers exist as a usable alternative. Due to the energy dependence of the attenuation coefficients, low-energy photons are preferably absorbed, causing a shift of the mean energy of the X-ray beam to higher values; this effect is known as beam hardening. Classical reconstruction methods assume a monochromatic source and do not take into account the polychromatic nature of the spectrum, producing two artifacts in the reconstructed image: 1) cupping in large homogeneous areas and 2) dark bands between dense objects such as bone. These artifacts hinder a correct visualization of the image and the recovery of the true attenuation coefficient values. A fast correction of the beam-hardening artifacts can be performed with the so-called post-processing methods, which use the information of a segmentation obtained in a preliminary reconstruction. Nevertheless, this segmentation may fail in low-dose scenarios, leading to an increase of the artifacts. An alternative for these scenarios is the use of iterative methods that incorporate a beam-hardening model, at a cost of higher of computational time compared to post-processing methods. All previously proposed methods require either knowledge of the X-ray spectrum, which is not always available, or the heuristic selection of some parameters, which have been shown not to be optimal for the correction of different slices in heterogeneous studies. This thesis is framed in a research line focused on improving radiology systems of the Biomedical Imaging and Instrumentation Group (BiiG) from the Bioengineering and Aerospace Department of Universidad Carlos III de Madrid. This research line is carried out in collaboration with the Unidad de Medicina y Cirugía experimental of Hospital Gregorio Marañón through Instituto de Investigación Sanitaria Gregorio Marañón, the Electrical Engineering and Computer Science (EECS) department of the University of Michigan and SEDECAL, a Spanish company among the ten best world companies in medical imaging that exports medical devices to 130 countries. As part of this research line, a high-resolution micro-CT was developed for small-animal samples, which operates at low voltages, leading to strong beam-hardening artifacts. This scanner allows preclinical studies to be carried out, which can be divided into cross-sectional and longitudinal studies. Since cross-sectional studies consist of one acquisition at a specific point in time, radiation dose is not an issue, allowing for the use of standard-dose protocols with good image quality. In contrast, longitudinal studies consist of several acquisitions over time, so it is advisable to use low-dose protocols, despite the reduction of signal to noise ratio and the risk of artifacts in the image. This thesis presents a bundle of reconstruction strategies to cope with the beam-hardening effect in different dose scenarios, overcoming the problems of methods previously proposed in the literature. Since image quality is not an issue in the standard-dose scenarios, the speed of the strategies becomes a priority, advising for post-processing strategies. The main advantage of the proposed post-processing strategy is the inclusion of empirical models of the beam-hardening effect, either through a simple calibration phantom or through the information provided by the sample, which eliminates the need of the knowledge of the spectrum or tunning parameters. The evaluation against previously proposed correction methods with real and simulated data showed a good artifact compensation for a standarddose scenario (cross-sectional studies), while not optimum in a low-dose scenario, as expected. For longitudinal studies, where the reduction of dose delivered to the sample is advisable, this thesis presents an iterative method that incorporates the mentioned experimental beam-hardening models. The evaluation with real and simulated data and different dose scenarios showed excellent results but with the known drawback of high computational time. Finally, a deep-learning approach was explored with the idea of looking for a joint solution that would require low-computational time and, at the same time, compensate the beam-hardening artifacts regardless the dose scenario. The chosen architecture is U-net++, based on an encoder-decoder, with the mean-squared error as the cost function. Results in real data showed a good compensation of the beam-hardening and low-dose artifacts with a considerable reduction of time, rising the interest of further exploring this path in the future. The incorporation of these reconstruction strategies in real scanners is straightforward, only requiring a small modification of the calibration step already implemented in commercial scanners. The methods are being transferred to the company SEDECAL for their implementation in the new generation of micro-CT scanners for preclinical research and a multipurpose C-arm for veterinary applications.Programa de Doctorado en Multimedia y Comunicaciones por la Universidad Carlos III de Madrid y la Universidad Rey Juan CarlosPresidente: Jorge Ripoll Lorenzo.- Secretario: José Vicente Manjón Herrera.- Vocal: Adam M. Alessi

Micro-Computed Tomography Semi-Empirical Beam Hardening Correction: Method And Application To Meteorites

X-ray micro-computed tomography (μCT) is able to non-destructively provide high- resolution 3D images of the internal structures of dense materials such as meteorites. The widespread availability of instruments capable of biomedical micro-computed tomography means there is ample access to scanners for the investigation of geomaterials, but the scan data can be susceptible to artifacts such as beam hardening, a consequence of high X-ray attenuation in these dense materials. A semi-empirical correction method for beam hardening and scatter that can be straightforwardly applied to available biomedical scanners is proposed and evaluated. This method uses aluminum as a single calibration material to significantly reduce or remove signal intensity errors (i.e. cupping) that occur as a result of beam hardening artifacts. X-ray transmission data are linearized using custom software. Results show that it is possible through careful analysis to determine an effective method of artifact correction for specified protocols using this implementation. Following correction and validation, this technique is applied to imaging of meteorite samples. Four meteorites are examined using μCT in combination with this processing technique: Three ordinary chondrites (Grimsby, Gao-Guenie, and Ozona) and an olivine diogenite (NWA 5480). Information from μCT is compared to that of traditional methods of analysis of meteoritic samples, and the advantages and disadvantages are discussed

Panel options for large precision radio telescopes

The Cornell Caltech Atacama Telescope (CCAT) is a 25 m diameter telescope that will operate at wavelengths as short as 200 microns. CCAT will have active surface control to correct for gravitational and thermal distortions in the reflector support structure. The accuracy and stability of the reflector panels are critical to meeting the 10 micron HWFE (half wave front error) for the whole system. A system analysis based upon a versatile generic panel design has been developed and applied to numerous possible panel configurations. The error analysis includes the manufacturing errors plus the distortions from gravity, wind and thermal environment. The system performance as a function of panel size and construction material is presented. A compound panel approach is also described in which the reflecting surface is provided by tiles mounted on thermally stable and stiff sub-frames. This approach separates the function of providing an accurate reflecting surface from the requirement for a stable structure that is attached to the reflector support structure on three computer controlled actuators. The analysis indicates that there are several compound panel configurations that will easily meet the stringent CCAT requirements