300 research outputs found
Relative Equilibria in the Four-Vortex Problem with Two Pairs of Equal Vorticities
We examine in detail the relative equilibria in the four-vortex problem where
two pairs of vortices have equal strength, that is, \Gamma_1 = \Gamma_2 = 1 and
\Gamma_3 = \Gamma_4 = m where m is a nonzero real parameter. One main result is
that for m > 0, the convex configurations all contain a line of symmetry,
forming a rhombus or an isosceles trapezoid. The rhombus solutions exist for
all m but the isosceles trapezoid case exists only when m is positive. In fact,
there exist asymmetric convex configurations when m < 0. In contrast to the
Newtonian four-body problem with two equal pairs of masses, where the symmetry
of all convex central configurations is unproven, the equations in the vortex
case are easier to handle, allowing for a complete classification of all
solutions. Precise counts on the number and type of solutions (equivalence
classes) for different values of m, as well as a description of some of the
bifurcations that occur, are provided. Our techniques involve a combination of
analysis and modern and computational algebraic geometry
Tomorrow’s world: Current developments in the therapeutic use of technology for psychosis
There is now an established evidence base for the use of information and communication technology (ICT) to support mental healthcare (‘e-mental health’) for common mental health problems. Recently, there have been significant develop-ments in the therapeutic use of computers, mobile phones, gaming and virtual reality technologies for the assessment and treatment of psychosis. We provide an overview of the therapeutic use of ICT for psychosis, drawing on searches of the scientific literature and the internet and using interviews with experts in the field. We outline interventions that are already relevant to clinical practice, some that may become available in the foreseeable future and emerging challenges for their implementation
Physico-chemical characteristics of Jharkhand and West Bengal thermal springs along SONATA mega lineament, India
The chemical and isotopic compositions of thermal springs located along the Son–Narmada–Tapti (SONATA) mega lineament in central India have been investigated. The issuing temperatures of the thermal waters vary from 31° to 89°C for the thermal springs and 24° to 25°C for the cold springs. These thermal springs are located on the Archean Chotanagpur Gneissic Complex (CGC) in the eastern part of peninsular India. The thermal springs are mostly alkaline in nature with pH varying from 7.5 to 9.5. Piper diagram suggests that the chemistry of the thermal waters is compatible with the granitic host rocks through which the waters circulate. Mineral saturation index suggests that the thermal waters are saturated with cristobalite and quartz at lower temperatures (less than ∼130 to 150°C), and calcite and forsterite at higher temperatures (∼160° to 250°C). The estimated reservoir temperature based on chemical geothermometers is in the range of 132°–265°C, which favours a medium enthalpy geothermal system. Oxygen isotope fractionation of Bakreswar and Tantloi thermal springs highlights a higher reservoir temperature than estimated by chemical geothermometer. Positive gravity anomalies over Bakreswar and Tantloi areas strongly suggest a basement/mantle upliftment or mafic intrusion which could account for the heat source close to the surface. However, the large negative gravity anomaly depression around the Surajkund and Katkamsandi thermal springs indicates presence of deep seated faults
Slow Schroedinger dynamics of gauged vortices
Multivortex dynamics in Manton's Schroedinger--Chern--Simons variant of the
Landau-Ginzburg model of thin superconductors is studied within a moduli space
approximation. It is shown that the reduced flow on M_N, the N vortex moduli
space, is hamiltonian with respect to \omega_{L^2}, the L^2 Kaehler form on
\M_N. A purely hamiltonian discussion of the conserved momenta associated with
the euclidean symmetry of the model is given, and it is shown that the
euclidean action on (M_N,\omega_{L^2}) is not hamiltonian. It is argued that
the N=3 flow is integrable in the sense of Liouville. Asymptotic formulae for
\omega_{L^2} and the reduced Hamiltonian for large intervortex separation are
conjectured. Using these, a qualitative analysis of internal 3-vortex dynamics
is given and a spectral stability analysis of certain rotating vortex polygons
is performed. Comparison is made with the dynamics of classical fluid point
vortices and geostrophic vortices.Comment: 22 pages, 2 figure
Pulmonary Hypertension Is a Frequent Event in Patients with Chronic Myeloid Leukemia Treated with Tyrosine Kinase Inhibitors
Poster presented at American Society of Clinical Oncology in Chicago Illinois.
Background: Tyrosine kinase inhibitors (TKI) are the current standard therapy for patients with chronic myeloid leukemia (CML). Fluid retention and pleural effusions have been reported in patients treated with TKIs, particularly with dasatinib. Although TKIs have been shown to reverse pulmonary hypertension (PH) in animal models, there have been some reports of development of reversible PH with dasatinib.
Methods: We conducted a retrospective analysis on 401 patients diagnosed with CML in chronic phase (CP) who were treated with TKIs (imatinib, dasatinib, or nilotinib) as initial therapy for CML and had a transthoracic echocardiogram (TTE) done at some point during the course of therapy. PH was diagnosed if the patient had an estimated right ventricular systolic pressure (RVSP) of 35 mm Hg or greater. Secondary causes of PH (systolic or diastolic dysfunction on TTE, chronic obstructive pulmonary diseases [COPD], obstructive sleep apnea [OSA] and pulmonary embolism) were investigated during chart review.
Results: Twenty (23%) out of 87 patients had evidence of PH by TTE; median age 57 years, with 46% being males. Six pts (30%) received nilotinib 400mg twice daily, 4 (20%) patients had imatinib (400mg; n=1, 600mg; n=1 and 800mg daily; n=2), and 10 (50%) patients received dasatinib (dose varied 40-140mg daily). Five (25%) patients had coronary artery disease, 9 (45%) had systemic hypertension, 2 (10%) had COPD and 3 (15%) had OSA. Thirteen pts had serial TTE to compare the progression of PH including 6 (7%) who had a TTE prior to starting TKI. Among these 13 pts with serial TTE, 7 had rising RVSP with one patient having mild global hypokinesia, another with diastolic dysfunction and another with OSA. Four of those 7 patients had normal RVSP on their TTE prior to starting therapy. Six other pts had improvement in the RVSP on serial TTE, 4 of them with systemic hypertension. Two of those 6 patients had elevated RVSP on their TTE prior to starting therapy; one pt had no change. Eleven patients had pleural effusions (7 dasatinib, 3 imatinib, 1 nilotinib) associated with PH.
Conclusions: TKI therapy is occasionally associated with development of PH, but RVSP may improve spontaneously in some patients. A prospective study is needed to further investigate the relationship between TKIs and the development of PH
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The design and fabrication of supramolecular semiconductor nanowires formed by benzothienobenzothiophene (BTBT)-conjugated peptides
π-Conjugated small molecules based on a [1]benzothieno[3,2-b]benzothiophene (BTBT) unit are of great research interest in the development of solution-processable semiconducting materials owing to their excellent charge-transport characteristics. However, the BTBT π-core has yet to be demonstrated in the form of electro-active one-dimensional (1D) nanowires that are self-assembled in aqueous media for potential use in bioelectronics and tissue engineering. Here we report the design, synthesis, and self-assembly of benzothienobenzothiophene (BTBT)–peptide conjugates, the BTBT–peptide (BTBT-C3–COHN-Ahx-VVAGKK-Am) and the C8-BTBT–peptide (C8-BTBT-C3–COHN-Ahx-VVAGKK-Am), as β-sheet forming amphiphilic molecules, which self-assemble into highly uniform nanofibers in water with diameters of 11–13(±1) nm and micron-size lengths. Spectroscopic characterization studies demonstrate the J-type π–π interactions among the BTBT molecules within the hydrophobic core of the self-assembled nanofibers yielding an electrical conductivity as high as 6.0 × 10−6 S cm−1. The BTBT π-core is demonstrated, for the first time, in the formation of self-assembled peptide 1D nanostructures in aqueous media for potential use in tissue engineering, bioelectronics and (opto)electronics. The conductivity achieved here is one of the highest reported to date in a non-doped state
Smart fuzzy logic control of photovoltaic system: Case study Kingdom of Saudi Arabia
Robust controls of photovoltaic (PV) system applications that include modular multilevel inverter (MMI) for interfacing stand-alone and grid-connected operating modes are investigated in this paper to overcome interfacing problems of two-level and three-level inverters. The MMI provides high-quality voltage, current, and power signals without additional filters, which reduces complexity and cost of interface circuits. A new control method of active and reactive power has been introduced for PV systems to get maximum power point (MPP) in various climatic circumstances. The steady-state and dynamic performances of MMI are investigated using MATLAB/Simulink. A fuzzy logic control is proposed to track the MPP utilizing the perturb and observe (P&O) technique. A fair comparison between fuzzy logic control and proportional integral (PI) control was conducted using MATLAB/Simulink. The fuzzy logic controller for obtaining MPPT by P&O method is proposed to get fast and accurate results. The obtained results obvioused that the fuzzy logic controller is quick accessing MPP than PI controller. A simple LC filter can achieve minimum harmonics provided by total harmonic distortion (THD) of MMI within IEEE limit. The PV system for standalone and grid-connected modes is being tested under climatic conditions in the city of Tabuk, Kingdom of Saudi Arabia (KSA). © 2023 Institute of Advanced Engineering and Science. All rights reserved
Holographic phase diagram of quark-gluon plasma formed in heavy-ions collisions
The phase diagram of quark gluon plasma (QGP) formed at a very early stage
just after the heavy ion collision is obtained by using a holographic dual
model for the heavy ion collision. In this dual model colliding ions are
described by the charged shock gravitational waves. Points on the phase diagram
correspond to the QGP or hadronic matter with given temperatures and chemical
potentials. The phase of QGP in dual terms is related to the case when the
collision of shock waves leads to formation of trapped surface. Hadronic matter
and other confined states correspond to the absence of trapped surface after
collision.
Multiplicity of the ion collision process is estimated in the dual language
as area of the trapped surface. We show that a non-zero chemical potential
reduces the multiplicity. To plot the phase diagram we use two different dual
models of colliding ions, the point and the wall shock waves, and find
qualitative agreement of the results.Comment: 33 pages, 14 figures, typos correcte
МЕТОДИКА ПОСТРОЕНИЯ И АНАЛИЗ ПОЛЕЙ ТОЧНОСТИ ГЛОНАСС В ЗАДАННОЙ ЗОНЕ ВОЗДУШНОГО ПРОСТРАНСТВА
Based on the usage of LabView’s developed program of orbital motion modeling and the choice of satellite’s working constellation, the methodology of building-up the fields of potential accuracy GLONASS in the given airspace has been proposed. The methods are based on the estimation of horizontal (HDOP) and vertical (VDOP) geometric factors’ values in points chosen with given latitude and longitude discontinuity in the airspace which is being studied. By relevant error handling the areas where the values of HDOP and VDOP lay within given range and their cartographic matching are selected. Expressions for geometric factors calculation are listed. By comparing the data of real experiments with semireal-istic simulation which have been conducted with the aeronautical receiver CH-4312 and the simulator CH-3803M, the validity of math model and the results’ accuracy have been evaluated. Investigations of geometric factors’ change in the initial and finishing points of flight route and also during the flight Irkutsk-Moscow have been conducted. As an example the fields of accuracy GLONASS in horizontal and vertical surfaces for the airspace between Irkutsk and Moscow have been built for such points in time that match the aircraft’s take off in Irkutsk and its landing in Moscow.На основе, разработанной в среде LabVieW, программы моделирования орбитального движения и выбора спутников рабочего созвездия предложена методика построения полей потенциальной точности ГЛОНАСС в заданной зоне воздушного пространства, базирующаяся на расчете геометрических факторов. Путем сравнения с данными натурных экспериментов и полунатурного моделирования оценена адекватность математической модели. Проведены исследования изменения геометрических факторов для маршрута Иркутск-Москва. Построены поля точности ГЛОНАСС в горизонтальной и вертикальной плоскостях для заданной зоны воздушно-го пространства
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