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How Irrelevant Operators affect the Determination of Fractional Charge  [PDF]
A. Koutouza,H. Saleur,B. Trauzettel
Physics , 2002, DOI: 10.1103/PhysRevLett.91.026801
Abstract: We show that the inclusion of irrelevant terms in the Hamiltonian describing tunneling between edge states in the fractional quantum Hall effect can lead to a variety of non perturbative behaviors in intermediate energy regimes, and, in particular, affect crucially the determination of charge through shot noise measurements. We show, for instance, that certain combinations of relevant and irrelevant terms can lead to an effective measured charge $\nu e$ in the strong backscattering limit and an effective measured charge $e$ in the weak backscattering limit, in sharp contrast with standard perturbative expectations. This provides a possible scenario to explain the experimental observations by Heiblum and coworkers, which are so far not understood.
Electrostatics and aggregation: how charge can turn a crystal into a gel  [PDF]
Jeremy Schmit,Stephen Whitelam,Ken Dill
Physics , 2010, DOI: 10.1063/1.3626803
Abstract: The crystallization of proteins or colloids is often hindered by the appearance of aggregates of low fractal dimension called gels. Here we study the effect of electrostatics upon crystal and gel formation using an analytic model of hard spheres bearing point charges and short range attractive interactions. We find that the chief electrostatic free energy cost of forming assemblies comes from the entropic loss of counterions that render assemblies charge-neutral. Because there exists more accessible volume for these counterions around an open gel than a dense crystal, there exists an electrostatic entropic driving force favoring the gel over the crystal. This driving force increases with increasing sphere charge, but can be counteracted by increasing counterion concentration. We show that these effects cannot be fully captured by pairwise-additive macroion interactions of the kind often used in simulations, and we show where on the phase diagram to go in order to suppress gel formation.
Charge migration in organic materials: Can propagating charges affect the key physical quantities controlling their motion?  [PDF]
C. Gollub,S. Avdoshenko,R. Gutierrez,Y. Berlin,G. Cuniberti
Physics , 2012,
Abstract: Charge migration is a ubiquitous phenomenon with profound implications throughout many areas of chemistry, physics, biology and materials science. The long-term vision of designing functional materials with tailored molecular scale properties has triggered an increasing quest to identify prototypical systems where truly molecular conduction pathways play a fundamental role. Such pathways can be formed due to the molecular organization of various organic materials and are widely used to discuss electronic properties at the nanometer scale. Here, we present a computational methodology to study charge propagation in organic molecular stacks at nano and sub-nanoscales and exploit this methodology to demonstrate that moving charge carriers strongly affect the values of the physical quantities controlling their motion. The approach is also expected to find broad application in the field of charge migration in soft matter systems.
Fatal Attraction: How Bacterial Adhesins Affect Host Signaling and What We Can Learn from Them  [PDF]
Daniel H. Stones,Anne-Marie Krachler
International Journal of Molecular Sciences , 2015, DOI: 10.3390/ijms16022626
Abstract: The ability of bacterial species to colonize and infect host organisms is critically dependent upon their capacity to adhere to cellular surfaces of the host. Adherence to cell surfaces is known to be essential for the activation and delivery of certain virulence factors, but can also directly affect host cell signaling to aid bacterial spread and survival. In this review we will discuss the recent advances in the field of bacterial adhesion, how we are beginning to unravel the effects adhesins have on host cell signaling, and how these changes aid the bacteria in terms of their survival and evasion of immune responses. Finally, we will highlight how the exploitation of bacterial adhesins may provide new therapeutic avenues for the treatment of a wide range of bacterial infections.
On how leakage can affect the Star Formation Rate estimation using Halpha luminosity  [PDF]
M. Relano,R. C. Jr. Kennicutt,J. J. Eldridge,J. C. Lee,S. Verley
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.21107.x
Abstract: We present observational evidence that leakage of ionising photons from star-forming regions can affect the quantification of the star formation rate (SFR) in galaxies. This effect could partially explain the differences between the SFR estimates using the far ultraviolet (FUV) and the Halpha emission. We find that leakage could decrease the SFR(Ha)/SFR(FUV) ratio by up to a 25 per cent. The evidence is based on the observation that the SFR(Ha)/SFR(FUV) ratio is lower for objects showing a shell Halpha structure than for regions exhibiting a much more compact morphology. The study has been performed on three object samples: low luminosity dwarf galaxies from the Local Volume Legacy survey and star-forming regions in the Large Magellanic Cloud and the nearby Local Group galaxy M33. For the three samples we find differences (1.1-1.4sigma) between the SFR(Ha)/SFR(FUV) for compact and shell objects. Although leakage cannot entirely explain the observed trend of SFR(Ha)/SFR(FUV) ratios for systems with low SFR, we show the mechanism can lead to different SFR estimates when using Halpha and FUV luminosities. Therefore, further study is needed to constrain the contribution of leakage to the low SFR(Ha)/SFR(FUV) ratios observed in dwarf galaxies and its impact on the Halpha flux as a SFR indicator in such objects.
Sad Cows and Empty Pockets: How Reviews, Recommendations, and Word-of-Mouth Can Affect Your Life
Kevin Hartford
Dalhousie Journal of Interdisciplinary Management , 2012, DOI: 10.5931/djim.v8i1.249
Abstract: For financial endeavours that affect their immediate financial and physical well-being – finding a doctor, hiring a lawyer - people turn to trustworthy sources like family and friends for advice. For more frivolous matters – what movie to see, what restaurant to frequent – people are more comfortable seeking a stranger's opinion via online reviews and recommendations. This paper examines the ways in which the presentation of online and offline information affect the decision-making process, as well as investigates the relevance of validity in subjective opinions.
How do chiral condensates affect color superconducting quark matter under charge neutrality constraints?  [PDF]
H. Abuki,M. Kitazawa,T. Kunihiro
Physics , 2004, DOI: 10.1016/j.physletb.2005.04.017
Abstract: We investigate the effects of the dynamical formation of the chiral condensates on color superconducting phases under the electric and color neutrality constraints at vanishing temperature. We shall show that the phase appearing next to the color-flavor-locked (CFL) phase down in density depends on the strength of the diquark coupling. In particular, the gapless CFL (gCFL) phase is realized only in a weak coupling regime. We give a qualitative argument on why the gCFL phase in the weak coupling region is replaced by some other phases in the strong coupling, once the competition between dynamical chiral symmetry breaking and the Cooper pair formation is taken into account.
Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach
J. G. Dyke, F. Gans,A. Kleidon
Earth System Dynamics (ESD) & Discussions (ESDD) , 2011, DOI: 10.5194/esd-2-139-2011
Abstract: Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.
Physiological modeling, tight glycemic control, and the ICU clinician: what are models and how can they affect practice?
J Geoffrey Chase, Aaron J Le Compte, J-C Preiser, Geoffrey M Shaw, Sophie Penning, Thomas Desaive
Annals of Intensive Care , 2011, DOI: 10.1186/2110-5820-1-11
Abstract: Computational models of human physiology offer the potential, with clinical data, to create patient-specific models that capture a patient's physiological status. Such models can provide new insights into patient condition by turning a series of sometimes confusing clinical data into a clear physiological picture. More directly, they can track patient-specific conditions and thus provide new means of diagnosis and opportunities for optimising therapy.This article presents the concept of model-based therapeutics, the use of computational models in clinical medicine and critical care in specific, as well as its potential clinical advantages, in a format designed for the clinical perspective. The review is presented in terms of a series of questions and answers. These aspects directly address questions concerning what makes a model, how it is made patient-specific, what it can be used for, its limitations and, importantly, what constitutes sufficient validation.To provide a concrete foundation, the concepts are presented broadly, but the details are given in terms of a specific case example. Specifically, tight glycemic control (TGC) is an area where inter- and intra-patient variability can dominate the quality of care control and care received from any given protocol. The overall review clearly shows the concept and significant clinical potential of using computational models in critical care medicine.Critically ill patients can be defined by the high variability in response to care and treatment. In particular, variability in outcome arises from variability in care and variability in the patient-specific response to care. The greater the variability, the more difficult the patient's management and the more likely a lesser outcome becomes. Hence, the recent increase in importance of protocolized care to minimize the iatrogenic component due to variability in care. Recent articles [1,2] have noted that protocols are potentially most applicable to groups with well-known
Can accretion disk properties distinguish gravastars from black holes?  [PDF]
Tiberiu Harko,Zoltán Kovács,Francisco S. N. Lobo
Physics , 2009, DOI: 10.1088/0264-9381/26/21/215006
Abstract: Gravastars, hypothetic astrophysical objects, consisting of a dark energy condensate surrounded by a strongly correlated thin shell of anisotropic matter, have been proposed as an alternative to the standard black hole picture of general relativity. Observationally distinguishing between astrophysical black holes and gravastars is a major challenge for this latter theoretical model. In the context of stationary and axially symmetrical geometries, a possibility of distinguishing gravastars from black holes is through the comparative study of thin accretion disks around rotating gravastars and Kerr-type black holes, respectively. In the present paper, we consider accretion disks around slowly rotating gravastars, with all the metric tensor components estimated up to the second order in the angular velocity. Due to the differences in the exterior geometry, the thermodynamic and electromagnetic properties of the disks (energy flux, temperature distribution and equilibrium radiation spectrum) are different for these two classes of compact objects, consequently giving clear observational signatures. In addition to this, it is also shown that the conversion efficiency of the accreting mass into radiation is always smaller than the conversion efficiency for black holes, i.e., gravastars provide a less efficient mechanism for converting mass to radiation than black holes. Thus, these observational signatures provide the possibility of clearly distinguishing rotating gravastars from Kerr-type black holes.
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