Central System Research Articles

Evaluation and Treatment of Alkalosis in Children.

Alkalosis is a disorder of acid-base balance defined by elevated pH of the arterial blood. Metabolic alkalosis is characterized by primary elevation of the serum bicarbonate. Due to several mechanisms, it is often associated with hypochloremia and hypokalemia and can only persist in the presence of factors causing and maintaining alkalosis. Respiratory alkalosis is a consequence of dysfunction of respiratory system's control center. There are no pathognomonic symptoms. History is important in the evaluation of alkalosis and usually reveals the cause. It is important to evaluate volemia during physical examination. Treatment must be causal and prognosis depends on a cause.

Periodic locomotion of a two‐body crawling system along a straight line on a rough inclined plane

AbstractThe motion of a two‐body limbless crawler along a line of maximum slope on an inclined plane is considered. Dry friction (anisotropic in the general case) acts between the system's bodies and the underlying plane. The motion is excited and controlled by a periodic change in the distance between the bodies. Of most interest is the periodic upward motion of the system, when the velocity of the system's center of mass changes periodically with a period coinciding with that of the excitation. A mathematical model of the crawler is presented. An upper bound for the inclination angles of the plane at which the system can move upward is estimated. This estimate is based on the averaged model, which implies smallness of the coefficient of friction. Numerical and physical simulation is performed to verify the theoretical results and define an applicability area for them.

The mass of the young planet Beta Pictoris b through the astrometric motion of its host star

The young massive Jupiters discovered with high-contrast imaging provide a unique opportunity to study the formation and early evolution of gas giant planets. A key question is to what extent gravitational energy from accreted gas contributes to the internal energy of a newly formed planet. This has led to a range of formation scenarios from 'cold' to 'hot' start models. For a planet of a given mass, these initial conditions govern its subsequent evolution in luminosity and radius. Except for upper limits from radial velocity studies, disk modelling, and dynamical instability arguments, no mass measurements of young planets are yet available to distinguish between these different models. Here we report on the detection of the astrometric motion of Beta Pictoris, the 21 Myr-old host star of an archetypical directly-imaged gas giant planet, around the system's centre of mass. Subtracting the highly accurate Hipparcos-Gaia proper motion from the internal 3-yr Hipparcos astrometric data reveals the reflex motion of the star, giving a model-independent planet mass of M=11+-2 MJup. This is consistent with scenarios in which the planet is formed in a high-entropy state as assumed by hot start models. The ongoing data collection by Gaia will in the near future lead to mass measurements of other young gas giants and form a great asset to further constrain early evolution scenarios.

Three-Axial Helmholtz Coil Design and Validation for Aerospace Applications

This paper presents the detailed design, construction, and validation of a three-axis square Helmholtz coil. It also describes the methodology used to drive each pair of coils as well as the setup to operate it in a closed-loop system using a digital PID controller. The coil will be mainly used for aerospace applications, especially to aid the development and testing of attitude determination and control systems that use the earth's magnetic field as a reference vector. Most of the system was built using commercial components, reducing cost, and complexity compared to similar commercial systems. The assembled Helmholtz coil has approximately one cubic meter and can generate magnetic fields up to 2 G/ axis, keeping a uniformity of 0.04% around 11 cm of the center, in each axis. A custom-designed voltage-controlled current source, based on the Howland current pump, was employed, requiring no complex electronic circuits. The coil was designed to be part of a hardware-in-the-loop (HiL) system, which is controlled by a dSPACE modular simulation hardware and uses a commercial fluxgate magnetometer as the reference. This setup reduces the complexity of the proposed system when compared to similar ones. This paper presents two distinct results: first, there is the validation and results of the uniformity regarding the generated field around the system's center; second, results of the setup with the closed-loop HiL simulation are shown, which includes tests of the coil when generating a dynamic magnetic field.

The covariant additive integrals of motion in the theory of Relativistic Vector Fields

The covariant expressions are derived for the energy, momentum, and angular momentum of an arbitrary physical system of particles and vector fields acting on them. These expressions are based on the Lagrange function of the system, are the additive integrals of motion, and are conserved over time in closed systems. The angular momentum pseudotensor and the radius-vector of the system's center of momentum are determined in a covariant form. By integrating the motion equation over the volume the integral vector is calculated and the impossibility of treatment of the integral vector as the system's four-momentum is proved as opposed to how it is done in the general theory of relativity. In contrast to the system's four-momentum, which collectively characterizes the motion of the system's particles in the surrounding fields, the physical meaning of the integral vector consists in the taking account of all the energies and energy fluxes of the fields generated by the particles. The difference between the four-momentum and the integral vector is associated not only with the duality of particles and fields, but also with different transformation laws for four-vectors and four-tensors of second order. As a result, the integral vector turns out to be a pseudo vector of a special kind.

The Content Validity of a Chemotherapy-Induced Peripheral Neuropathy Patient-Reported Outcome Measure.

To test the content validity of a 16-item version of the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy (QLQ-CIPN20). . Cross-sectional, prospective, qualitative design. . Six outpatient oncology clinics within the University of Michigan Health System's comprehensive cancer center in Ann Arbor. . 25 adults with multiple myeloma or breast, gynecologic, gastrointestinal, or head and neck malignancies experiencing peripheral neuropathy caused by neurotoxic chemotherapy. . Cognitive interviewing methodology was used to evaluate the content validity of a 16-item version of the QLQ-CIPN20 instrument. . Minor changes were made to three questions to enhance readability. Twelve questions were revised to define unfamiliar terminology, clarify the location of neuropathy, and emphasize important aspects. One question was deleted because of clinical and conceptual redundancy with other items, as well as concerns regarding generalizability and social desirability. . Cognitive interviewing methodology revealed inconsistencies between patients' understanding and researchers' intent, along with points that required clarification to avoid misunderstanding. . Patients' interpretations of the instrument's items were inconsistent with the intended meanings of the questions. One item was dropped and others were revised, resulting in greater consistency in how patients, clinicians, and researchers interpreted the items' meanings and improving the instrument's content validity. Following additional revision and psychometric testing, the QLQ-CIPN20 could evolve into a gold-standard CIPN patient-reported outcome measure.

Evaluating how species niche modelling is affected by partial distributions with an empirical case

Ecological niche models (ENMs) will successfully identify a species' ecological niche, provided that important assumptions are fulfilled, namely environment equilibrium and niche equality across the distribution. Violations may seriously affect ENM reliability, leading to erroneous biogeographic conclusions and inappropriate conservation prioritisation. We evaluate the robustness of ENMs against incomplete knowledge of distribution with a real example, the threatened Iberian lizard Podarcis carbonelli, whose distribution was gradually discovered over a long time period. We used several ENM methods for presence-only data (Maxent, ENFA, Bioclim, and Domain) to infer the realised ecological niche at two spatial resolutions (1 km and 200 m). The distribution data were split into four partial datasets corresponding to separate subranges: Central System (CS); Viseu-Aveiro (VA); Atlantic coast (AC); and Doñana (DO). We then accumulated the datasets following the species discovery sequence: CS + VA, CS + VA + AC, and CS + VA + AC + DO. Niche equivalence and similarity between partial models were compared using Ecospat. ENMs were strongly affected by the violation of niche equilibrium; only the VA subrange forecasts the complete species range. ENMs were also sensitive to the violation of niche equality: only VA models were similar to the Iberian model, altitude being the most important variable followed by annual precipitation, maximum temperature in July, and annual radiation. When the ENMs were applied only to the first subrange discovered (CS), only the VA area was predicted, while the other subranges might have remained unknown, thus compromising conservation strategies. As assumptions of niche equilibrium and equality were violated, likely owing to the species' ecological multimodality, the models generated were biased and of limited predictive value. ENMs are useful tools in biogeography and conservation, but only if their basal assumptions are achieved. Partial models may be useful if they are considered as representing different suitable habitats.

Excitation spectra of a Bose-Einstein condensate with an angular spin-orbit coupling

A theoretical model of a Bose-Einstein condensate with angular spin-orbit coupling has recently been proposed and it has been established that a half-skyrmion represents the ground state in a certain regime of spin-orbit coupling and interaction. Here we investigate low-lying excitations of this phase by using the Bogoliubov method and numerical simulations of the time-dependent Gross-Pitaevskii equation. We find that a sudden shift of the trap bottom results in a complex two-dimensional motion of the system's center of mass that is markedly different from the response of a competing phase, and comprises two dominant frequencies. Moreover, the breathing mode frequency of the half-skyrmion is set by both the spin-orbit coupling and the interaction strength, while in the competing state it takes a universal value. Effects of interactions are especially pronounced at the transition between the two phases.

Efficient single-photon absorption by a trapped moving atom

The influence of the center of mass motion of a trapped two level system on efficient resonant single photon absorption is investigated. It is shown that this absorption process depends strongly on the ratio between the characteristic time scales of spontaneous photon emission and of the two level system's center of mass motion. In particular, if the spontaneous photon emission process occurs almost instantaneously on the time scale of the center of mass motion coherent control of the center of mass motion offers interesting perspectives for optimizing single photon absorption. It is demonstrated that this way time dependent modulation of a harmonic trapping frequency allows to squeeze the two level system's center of mass motion so strongly that high efficient single photon absorption is possible even in cases of weak confinement by a trapping potential.

PACKING CIRCLES WITHIN CIRCULAR CONTAINERS: A NEW HEURISTIC ALGORITHM FOR THE BALANCE CONSTRAINTS CASE

In this work we propose a heuristic algorithm for the layout optimization for disks installed in a rotating circular container. This is a unequal circle packing problem with additional balance constraints. It proved to be an NP-hard problem, which justifies heuristics methods for its resolution in larger instances. The main feature of our heuristic is based on the selection of the next circle to be placed inside the container according to the position of the system's center of mass. Our approach has been tested on a series of instances up to 55 circles and compared with the literature. Computational results show good performance in terms of solution quality and computational time for the proposed algorithm.

A Predictive Generator Out-of-Step Protection and Transient Stability Monitoring Scheme Enabled by a Distributed Dynamic State Estimator

A novel predictive generator out-of-step protection and transient stability monitoring scheme is presented. It is based on real-time dynamic monitoring of the system, enabled by a distributed dynamic state estimator (DSE). DSE utilizes local synchronized and nonsynchronized measurements and provides the evolution of the system's dynamic state at rates of 60 times/s. The real-time dynamic model is then utilized to evaluate the system's energy function based on Lyapunov's direct method, estimate the stability barrier, and characterize its stability. The two major components of the scheme are: 1) the calculation of the system's center of oscillations and 2) the derivation in real time of an equivalent, reduced size model used for the calculation of the generator stability barrier and its stability characterization. It is shown that the major advantage of the proposed scheme, compared with legacy generator impedance relay-based out-of-step protection, is that the out-of-step condition is predicted before its occurrence and the generator can be tripped much faster than the traditional scheme. The theoretical background of the scheme and application on an actual system are presented. The proposed scheme characterizes very accurate potential generator instability and predicts generator loss of synchronism before its occurrence, before the generator slips a pole.

Transformations of asymptotic gravitational-wave data

Gravitational-wave data is gauge dependent. While we can restrict the class of gauges in which such data may be expressed, there will still be an infinite-dimensional group of transformations allowed while remaining in this class, and almost as many different---though physically equivalent---waveforms as there are transformations. This paper presents a method for calculating the effects of the most important transformation group, the Bondi-Metzner-Sachs (BMS) group, consisting of rotations, boosts, and supertranslations (which include time and space translations as special cases). To a reasonable approximation, these transformations result in simple coupling between the modes in a spin-weighted spherical-harmonic decomposition of the waveform. It is shown that waveforms from simulated compact binaries in the publicly available SXS waveform catalog contain unmodeled effects due to displacement and drift of the center of mass, accounting for mode-mixing at typical levels of 1%. However, these effects can be mitigated by measuring the average motion of the system's center of mass for a portion of the inspiral, and applying the opposite transformation to the waveform data. More generally, controlling the BMS transformations will be necessary to eliminate the gauge ambiguity inherent in gravitational-wave data for both numerical and analytical waveforms. Open-source code implementing BMS transformations of waveforms is included along with this paper in the supplemental materials.

Improving adherence to the Epic Beacon ambulatory workflow.

Computerized physician order entry has been shown to significantly improve chemotherapy safety by reducing the number of prescribing errors. Epic's Beacon Oncology Information System of computerized physician order entry and electronic medication administration was implemented in Henry Ford Health System's ambulatory oncology infusion centers on 9 November 2013. Since that time, compliance to the infusion workflow had not been assessed. The objective of this study was to optimize the current workflow and improve the compliance to this workflow in the ambulatory oncology setting. This study was a retrospective, quasi-experimental study which analyzed the composite workflow compliance rate of patient encounters from 9 to 23 November 2014. Based on this analysis, an intervention was identified and implemented in February 2015 to improve workflow compliance. The primary endpoint was to compare the composite compliance rate to the Beacon workflow before and after a pharmacy-initiated intervention. The intervention, which was education of infusion center staff, was initiated by ambulatory-based, oncology pharmacists and implemented by a multi-disciplinary team of pharmacists and nurses. The composite compliance rate was then reassessed for patient encounters from 2 to 13 March 2015 in order to analyze the effects of the determined intervention on compliance. The initial analysis in November 2014 revealed a composite compliance rate of 38%, and data analysis after the intervention revealed a statistically significant increase in the composite compliance rate to 83% ( p < 0.001). This study supports a pharmacist-initiated educational intervention can improve compliance to an ambulatory, oncology infusion workflow.

Abstract B07: Design and preliminary outcomes of a study to reduce cancer-associated reactive metabolite levels in breast cancer survivors – The RCAM Study

Abstract Breast cancer (BCa) is the 2nd leading cause of cancer death in women in the US. African American (AA) women have higher BCa mortality rates and higher obesity rates compared to other women. It is well known that exercise and a healthier diet can improve prognosis among BCa survivors but little is known about their positive effects on common biological pathways involved in BCa recurrence. The RCAM Study is a 1-year study designed to identify bio-behavioral pathways that may impact BCa recurrence. The study evaluates the effect of the intervention on a novel biomarker associated with cancer recurrence advanced glycation end products (AGEs). The intervention, adapted from the highly successful Diabetes Prevention Program (DPP), consists of a 12-week physical activity and dietary counseling program. The supervised physical activity component is conducted twice a week at a local health system's cardiopulmonary rehabilitation center; the individualized dietary counseling component is conducted weekly at the health system's weight management center. The study participants consist of overweight or obese women who received surgery for invasive BCa and who are within 36 months of diagnosis. In addition, adjuvant therapy must have been received at least four weeks prior to study enrollment. To date, 10 participants have completed the 12-week intervention and will be followed for 1 year. Preliminary ELISA data from blood samples collected pre- and post-12 week intervention show significant post-intervention reductions in inflammatory biomarker levels. Commensurate decreases in body mass, resting heart rate, and blood pressure were also seen. The average pre-/post-intervention decrease in AGE levels was not as dramatic for the AA participants, most of whom were morbidly obese at enrollment, as for the European American (EA) women, most of whom were overweight at enrollment. These data demonstrate the high potential of the RCAM intervention in improving prognosis among BCa survivors and show the need to tailor the intervention to meet the specific needs of AA women. Citation Format: Marvella E. Ford, David P. Turner, Mathew J. Gregoski, Lindsay L. Peterson, Kendrea D. Knight, Ebony J. Hilton, Gayenell Magwood. Design and preliminary outcomes of a study to reduce cancer-associated reactive metabolite levels in breast cancer survivors – The RCAM Study. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr B07.

Measurement Properties of a Modified Measure of Participation for Persons with Spinal Cord Injury

Objective: The primary aim of this study was to examine and refine a modified measure of participation for adults with spinal cord injury (SCI) based on a conceptual model of participation.Method: This study involved secondary analysis of data from a larger study designed to identify a standard measure of participation for use in SCI research. The larger study recruited 634 community-dwelling adults with SCI from seven collaborating SCI Model Systems Centers, of whom 520 subjects (average age 45.1 ± 13.6 years, 76% were male) completed the survey that is the focus of the present analysis. Content review, confirmatory factor analysis (CFA), Rasch analysis, and precision analysis were employed to select the items for the modified participation measure.Results: Three participation domains were supported: Productivity, Social, and Community, that displayed good model-fit (CFI=0.984, TLI=0.982, RMSEA=0.043) in CFA and good item-fit (infit= 0.6 to 1.4) in Rasch analysis. Differential Item Functioning (DIF) was ...

On the motion of lumped‐mass and distributed‐mass self‐propelling systems in a linear resistive environment

The motion of self‐propelling limbless locomotion systems in a linear viscous environment is considered. The resistance (friction) force acting on an element of the systems is assumed to be proportional to the velocity of this element relative to the environment, the coefficient of proportionality (coefficient of friction) being constant. Two models of interaction of the locomotor with the environment are distinguished. In the first model, the coefficient of friction is constant for a mass element, whereas in the second model, this coefficient is constant for a length element. It is shown that progressive locomotion is impossible for the first model and is possible for the second model. This is explained by the fact that in the second model, the coefficient of friction for a mass element is in fact controlled by changing the length of this element due to deformation of the locomotor's body. The first model applies for lumped mass systems, while the second model is adequate for distributed mass limbless locomotors, like worms. For both models, the equations of motion of the system's center of mass are derived and analyzed.

Interaction of a magnet and a point charge: Unrecognized internal electromagnetic momentum

Whereas nonrelativistic mechanics always connects the total momentum of a system to the motion of the center of mass, relativistic systems, such as interacting electromagnetic charges, can have internal linear momentum in the absence of motion of the system's center of energy. This internal linear momentum of a system is related to the controversial concept of “hidden momentum.” We suggest that the term “hidden momentum” be abandoned. Here, we use the relativistic conservation law for the center of energy to give an unambiguous definition of the “internal momentum of a system,” and then we exhibit this internal momentum for the system of a magnet (modeled as a circular ring of moving charges) and a distant static point charge. The calculations provide clear illustrations of this system for three cases: (a) the moving charges of the magnet are assumed to continue in their unperturbed motion; (b) the moving charges of the magnet are free to accelerate but have no mutual interactions; and (c) the moving charges of the magnet are free to accelerate and also interact with each other. When the current-carrying charges of the magnet are allowed to interact, the magnet itself will contain internal electromagnetic linear momentum, something that has not been described clearly in the research and teaching literature.

P039 Triple negative breast cancer (TNBC): clinical utility of immunohistochemical classification

Goals: To determine differences in TNBC between expression of cytokeratins 5 and 6 (CK 5/6) and their prognosis. Methods: Data from 888 consecutive female patients with invasive breast cancer but without metastatic disease, who had undergone surgery and were registered between 1 January 1997 and 31 December 2004 in the Tumour Registry of the University Hospital of Ourense (CHUO), Galicia, Spain, were collated and analysed. 100 of them were triple negative breast cancer. IHC was then performed on archived biopsies from the patients, who were thus classified by breast cancer subtype. First, a descriptive analysis of the study population was performed. Qualitative variables were analysed as absolute percentages and relative frequencies, and quantitative variables in terms of central tendency values, i.e. mean. Statistical analyses were then performed, using statistical tests appropriate to each type of variable, i.e. Chi-square test or Fisher’s exact test. Global survival and disease-free survival, using Cox regressions and Kaplan–Meier estimates, were calculated for classical prognostic variables (included age, tumour size and grade, node involvement). We present the results of triple negative breast cancer cases, which were divided in “basal like” and “no basal like” by CK 5/6 expression. SPSS version 17.0 (SPSS Inc., Chicago, IL) was used for all statistical analyses. Results were considered significant when p < 0.05. Results: One hundred triple negative (11.26%) cases among a total of 888 breast cancers were identified: 48 basal like (48%), 45 (45%) no basal like and 7 of them unclassified, because it was not possible to find histological samples. The basal like subtype showed CK 5/6 expression and no basal like absence of this expression. The relapse happened in 28% of TNBC. 42% of the relapses were visceral metastasis, 10% in nervous central system (CNS) and 7% in bones. There was more recurrences in CNS in basal-like than no basal like subtype (11 versus 7%) There was much more mortality-related breast cancer in basal like than in patients with the no basal like subtype (23% versus 18%) and much higher non-cancer-related mortality in patients with no basal like subtype. Patients without node involvement (N0) and basal like subtype had more relapses than no basal like subtype (22 versus 12.5%). None of the no basal like subtype patients died. Nevertheless, 22% of patients of basal like subtype died. Conclusion: TNBC is a bad prognostic factor in multivariate analyses, independent of size, nodal involvement and grading. By immunohistochemical expression of CK 5/6 we classified TNBC in basal like and no basal like subtypes, founded prognostic differences. Even though patients with no basal like tumors relapse, it seems that they have a lesser aggressive behavior. In contrast, basal like subtype tumors have a threatening prognosis with a short time between relapse and death. This evidence must make us think about the consideration of more intense adjuvant therapy in basal like TNBC to decrease relapse and death. Disclosure of Interest: No significant relationships.

Nonlinear dynamics of a rotating triangular tethered satellite formation near libration points

The nonlinear coupled dynamics of a rotating triangular tethered satellite formation near libration points is presented. Based on Hill's approximation, the dynamical formulation for a rotating triangular tethered system near libration points is developed. The formulation comprises a set of strong nonlinear coupled equations. Numerical simulations using the full nonlinear and time-varying motion equations are performed for the station-keeping stages. The dynamic characteristics of the triangular tethered formation are analyzed. The numerical results demonstrate that the rotation rate has a significant impact on the stability of the system, whereas the orbital amplitude has a moderate impact on the stability of the system. Tether length has little effect on the motion of the system's center of mass. It can be served as a basis to solve the problem of rotating triangular tethered systems in any arbitrary plane.

Orbital Debris Assessment Testing in the AEDC Range G

The space environment presents many hazards for satellites and spacecraft. One of the major hazards is hypervelocity impacts from uncontrolled man-made space debris. Arnold Engineering Development Complex (AEDC), the National Aeronautics and Space Administration (NASA), the United States Air Force Space and Missile Systems Center (SMC), the University of Florida, and the Aerospace Corporation configured a large ballistic range to perform a series of hypervelocity destructive impact tests in order to better understand the effects of space collisions. The test utilized AEDC's Range G light gas launcher, which is capable of firing projectiles up to 7km/sec. A nonfunctional full-scale representation of a modern satellite called the DebriSat was destroyed in the enclosed range environment. Several modifications to the range facility were made to ensure quality data was obtained from the impact events. The facility modifcations were intended to provide a high-impact energy-to-target-mass ratio (>200J/g), a nondamaging method of debris collection, and an instrumentation suite capable of providing information on the physics of the entire impact event.