A5059673962- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Noncommutative and Quantum Gravity Theories
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Gamma-ray bursts and supernovae
- Advanced Thermodynamics and Statistical Mechanics
- Asthma and respiratory diseases
- Nonlinear Dynamics and Pattern Formation
- Cardiovascular Health and Disease Prevention
- Gastrointestinal motility and disorders
- Blood Pressure and Hypertension Studies
- Neonatal Respiratory Health Research
- Data-Driven Disease Surveillance
- Second Language Acquisition and Learning
- Otolaryngology and Infectious Diseases
- Environmental Monitoring and Data Management
- Vitamin D Research Studies
- Childhood Cancer Survivors' Quality of Life
- Inertial Sensor and Navigation
- COVID-19 and healthcare impacts
- Radioactive contamination and transfer
- Advanced Neuroimaging Techniques and Applications
- Muscle and Compartmental Disorders
- Atomic and Subatomic Physics Research
Koç University
2020-2023
Albany Medical Center Hospital
2010-2023
University of Tübingen
2019-2020
University of Iowa
2020
University of Nottingham
2009-2018
Mater Children's Hospital
2005-2012
Manhattan Psychiatric Center
2009-2010
Mater Adult Hospital
2007
Covance (United States)
1998
Hill College
1984
We show that self-interacting vector field theories exhibit unphysical behavior even when they are not coupled to any external field. This means theory featuring such vectors is in danger of being unphysical, an alarming prospect for many proposals cosmology, gravity, high energy physics, and beyond. The problem arises fields with healthy configurations naturally reach a point where time evolution mathematically ill defined. develop tools easily identify this issue, provide simple unifying...
Spontaneous scalarization is a mechanism that allows scalar field to go undetected in weak gravity environments and yet develop nontrivial configuration strongly gravitating systems. At the perturbative level it manifests as tachyonic instability around spacetimes solve Einstein's equations. The endpoint of this can significantly modify compact object's structure produce observational signatures field's presence. Does such exists for vector fields? Here we revisit model constitutes most...
Self-interacting vectors are seeing a burst of interest where various groups demonstrated that the field evolution ends in finite time. Two nonequivalent criteria have been offered to identify this breakdown: (i) vector constraint equation cannot be satisfied beyond point breakdown occurs, (ii) dynamics is governed by an effective metric becomes singular at breakdown. We show identifies coordinate singularity, and can removed change coordinates. Hence, it does not signify physical problem,...
In recent papers it has been shown that a large class of vectorization mechanisms in gravity, which involve the vector fields becoming apparently tachyonic some regime, are actually dominated by ghosts and nonperturbative behavior. Despite this, vectorized compact object solutions have previously found, raises question how, if, newly discovered quenched these cases. Here we develop tools to study perturbations objects, demonstrate they suffer from gradient instabilities as well. Thus,...
ABSTRACT Background and objective: Advances in statistical modelling have allowed the creation of smoothly changing spirometry reference ranges that apply across a wide age range better define lower limit normal. The objective this study was to assess agreement Stanojevic 2009 all‐age contemporary lung function data verify appropriateness for clinical use Australia New Zealand. Methods: Spirometry from healthy Caucasians measured between 2000–2009 Zealand were collected. Z‐scores calculated...
Various groups recently argued that self-interacting vector field theories lack a well-defined time evolution when the grows to large amplitudes, which has drastic consequences for models in gravity and high energy theory. Such amplitudes can be result of an external driving mechanism, or occur intrinsically, due values its derivatives initial data. This brings natural question: Is small amplitude data guaranteed evolve indefinitely these absence outside term? We answer this question...
Summary Fifty-three hospitalized chronic schizophrenic patients were treated with either propranolol, chlorpromazine or placebo in a double-blind randomized trial for up to three months. Propranolol usual dose of 640 mg/day, produced marked cardiovascular effects but no improvement symptomatology relative placebo. The small and inconsistent.
The cuscuton is a scalar field with infinite speed of propagation. It was introduced in the context cosmology but it has also been claimed to resemble Ho\ifmmode \check{r}\else \v{r}\fi{}ava gravity certain limit. Here we revisit theory as Lorentz-violating theory. We clarify its relation and Einstein-\ae{}ther theory, analyze causal structure, consider initial value formulation. Finally, discuss which extent can be used proxy for gravitational collapse formation universal horizons.
In this Letter, we study black hole area quantization in the context of gravitational wave physics. It was recently argued that could be a mechanism to produce so-called echoes as well characteristic absorption lines observations merging holes. One can match spontaneous decay these quantum holes Hawking radiation calculations. Using some assumptions, one then estimate natural widths states. As seen from classical paper by Bekenstein and Mukhanov, ratio between width spacing nonspinning...
In Ho\v{r}ava-Lifshitz gravity a scaling isotropic in space but anisotropic spacetime, often called with the dynamical critical exponent z=3, lies at base of its renormalizability. This also leads to novel mechanism generating scale-invariant cosmological perturbations, solving horizon problem without inflation. this paper we propose possible solution flatness problem, which assume that initial condition Universe is set by small instanton respecting same scaling. We argue may be more general...
Various groups recently demonstrated that the time evolution of simplest self-interacting vector fields, those with self-interaction potentials, can break down after a finite duration in what is called loss hyperbolicity. We establish this not an isolated issue, and other generalizations Proca theory suffer from same problem. Specifically, we show field theories derivative self-interactions have similar pathology. For this, derive effective metric governs dynamics, it change signature during...
We demonstrate some shortcomings of ``fixing the equations,'' an increasingly popular remedy for time evolution problems effective field theories (EFTs). compare EFTs and their ``fixed'' versions to UV from which they can be derived in two cases: K-essence nonlinear Proca theory. find that when EFT breaks down due loss hyperbolicity, fixing does not approximate theory well if solution quickly settle vacuum. argue this related approximation itself becoming invalid, cannot rectified by fixing.
We suggest that nonminimally coupled scalar fields can lead to modifications of the microphysics in interiors relativistic stars. As a concrete example, we consider generation nonzero photon mass such high-density environments. This is achieved by means light gravitational scalar, and scalarization phase transition scalar-tensor theories gravitation. Two distinct models are presented, phenomenological implications briefly discussed.
Studies have shown that increased arterial stiffening can be an indication of cardiovascular diseases like hypertension. In clinical practice, this detected by measuring the blood pressure (BP) using a sphygmomanometer but it cannot used for prolonged monitoring. It has been established pulse wave velocity (PWV) is direct measure its usefulness hampered absence non-invasive techniques to estimate it. Pulse transit time (PTT) simple and method derived from PWV. However, limited knowledge PTT...
We revisit the mixed-derivative extension of Ho\ifmmode \check{r}\else \v{r}\fi{}ava gravity which was designed to address naturalness problems standard theory in presence matter couplings. consider minimal with terms that contain two spatial and temporal derivatives. Including all compatible (modified) scaling rules foliation-preserving diffeomorphisms, we calculate dispersion relations propagating modes. find contains four degrees freedom, as opposed three gravity. The new degree freedom...
In this work we argue that black hole area quantization of Bekenstein and Mukhanov should not give rise to measurable effects in terms so-called gravitational wave echoes during mergers. We outline the quantum spectrum a be washed out after mergers, hence one expect scenario. The extreme broadening is due large particle emission rate ringdown. Our results question key assumptions being made recent literature on topic.
Aim: To evaluate the impact of early vs late palliative care on (1) length stay (LOS) in context expected LOS measures and (2) total cost to hospital for each patient. Methods: A prospective cohort study was performed at a single large academic medical center patients who received an inpatient consultation. The two cohorts were (within 3 days admission) (after admission). Comparisons made between patients' actual LOS, costs both cohorts. Results: Compared (N = 126), 68) had significantly...
In scalar-tensor theories, spontaneous scalarization is a phase transition that can occur in ultradense environments such as neutron stars. The scalar field develops nontrivial configuration once the stars exceeds compactness threshold. We recently pointed out that, if exhibits some additional coupling to matter, it could give rise significantly different microphysics these environments. this work we study, at nonperturbative level, toy model which photon given large mass when occurs. Our...
Introduction Urokinase receptor (uPAR, CD87), a glycosylphosphatidylinositol-anchored protein, is considered to play an important role in inflammation and fibrinolysis.The Gram-negative bacterium Burkholderia pseudomallei able survive replicate within leukocytes causes melioidosis, cause of pneumonia-derived community-acquired sepsis Southeast Asia.We here investigated the expression function uPAR both patients with septic melioidosis murine model experimental melioidosis.Methods Using...
Norelli LJ, Coates AD, Kovasznay BM. Cancer risk from diagnostic radiology in a deliberate self‐harm patient. Objective: Patients who engage recurrent (DSH) behaviours have increased morbidity and mortality use emergency services more than others. Unrecognized iatrogenic injury may play role. Specifically, we call attention to the potential danger of cumulative radiation exposure. Method: Case presentation discussion. Results: A 29‐year‐old woman with multiple episodes foreign body ingestion...