3,425 research outputs found
Boundary regularity for the Poisson equation in reifenberg-flat domains
This paper is devoted to the investigation of the boundary regularity for the
Poisson equation {{cc} -\Delta u = f & \text{in} \Omega u= 0 & \text{on}
\partial \Omega where belongs to some and is a
Reifenberg-flat domain of More precisely, we prove that given an
exponent , there exists an such that the
solution to the previous system is locally H\"older continuous provided
that is -Reifenberg-flat. The proof is based on
Alt-Caffarelli-Friedman's monotonicity formula and Morrey-Campanato theorem
Stabilization of multiple resistance levels by current-sweep in SiOx-based resistive switching memory
Using current-sweep measurements, the set process in SiOx-based resistive random access memory (RRAM) has been found to consist of multiple resistance-reduction steps. Variation in set behaviors was observed and attributed to different defect distributions in the resistance switching region. Physical mechanism of electroforming process is discussed, which further explains the observed variation of defect distributions. A compliance current study confirms that the achievable memory states of SiOx RRAM are determined by its set behavior. This finding provides additional insight on achieving multi-bit memory storage with SiOx RRAM. (C) 2015 AIP Publishing LLC.Microelectronics Research Cente
Emergent Properties: Team Teaching in Literature and Biology
In this essay, we reflect on the outcomes of our interdisciplinary, team-taught, undergraduate core course in modern literature and evolutionary biology--a course designed to study the problems of identifying the emergence of distinctly âhumanâ beings. The essay reflects on the positive, unexpected outcomes that we experienced, especially in student writing, via the metaphor of âemergent properties,â a biological term that refers to how new and complex traits, behaviors, or life forms emerge from the interaction of âsimpler unitsâ which in themselves would not produce these properties. Given that so much of the course content came from the students themselvesâin particular, from their interest in the question of human consciousness as an evolved traitâwe have incorporated excerpts from student essays that were produced for the course. These excerpts are preceded by student reflections and accompanied by observations about the compelling fashion in which students synthesized not only scientific and literary content, but also objective and subjective writing styles
Scaling laws for the photo-ionisation cross section of two-electron atoms
The cross sections for single-electron photo-ionisation in two-electron atoms
show fluctuations which decrease in amplitude when approaching the
double-ionisation threshold. Based on semiclassical closed orbit theory, we
show that the algebraic decay of the fluctuations can be characterised in terms
of a threshold law as with exponent
obtained as a combination of stability exponents of the triple-collision
singularity. It differs from Wannier's exponent dominating double ionisation
processes. The details of the fluctuations are linked to a set of infinitely
unstable classical orbits starting and ending in the non-regularisable triple
collision. The findings are compared with quantum calculations for a model
system, namely collinear helium.Comment: 4 pages, 1 figur
Distinguishing selection pressures in an evolving communication system: Evidence from colournaming in 'cross signing'
Cross-signingâthe emergence of an interlanguage between users of different sign languagesâoffers a rare chance to examine the evolution of a natural communication system in real time. To provide an insight into this process, we analyse an annotated video corpus of 340 minutes of interaction between signers of different language backgrounds on their first meeting and after living with each other for several weeks. We focus on the evolution of shared color terms and examine the role of different selectional pressures, including frequency, content, coordination and interactional context. We show that attentional factors in interaction play a crucial role. This suggests that understanding meta-communication is critical for explaining the cultural evolution of linguistic systems
Diagnosis of flood events in Brisbane (Australia) using a flood index based on daily effective precipitation
Like drought, flood events are extremely detrimental to the community [1, 2]. In the State of Queensland (Australia) the 2010â2011 Summer period saw a very significant flooding that appeared to be exacerbated by La Nina, with damages of magnitudes similar to previous flood in 1974 and mid-1950s [3]. Therefore, a plethora of flood events in this region raises serious questions about how best to address the vulnerability and costs [4]. Several studies documented particularly vulnerable geographic setting of the capital city, Brisbane. To name a few, the worst event was in January 1974 and next in 2010, which flooded most dwellings around Brisbane River catchment, severely in Toowoomba and the Lockyer Creek catchment (where 23 people had drowned). Insurers received some 56,200 claims with payouts totaling $2.55 billion, due to estimated inundations of 18,000 properties. Crucial to any flood mitigation and adaptation is the prediction of events with a good real-time monitoring system. The system should detect precisely the onset dates and corresponding water-intensive properties. A flood event is dependent on how abundant the water resources due to heavy rain are and how the water is dissipated over time. Hence a scientific method for detecting floods should be based on remaining effective precipitation on daily basis, due to heavy rain over a period of time. In this paper we applied an obje400+-ctive flood diagnostic method following an earlier pioneer study [6]. The Flood Index (FI) used in this research was initially developed by [6] based on the concept of daily Effective Precipitation (EP) proposed by [7] using the Available Water Resources Index (AWRI), and later used by [8] for analysis of water abundant seasons. The daily FI was applied to the flood region of Brisbane, the state capital of Queensland, Australia (27°30' S, 153°1' E). In order to compute the FI, the pre-processed daily rainfall data was acquired from Australian Bureau of Meteorology (http://www.bom.gov.au/climate/data-services/). Data for the period 1915â2012 were analysed. Since the FI was a standardized value comparing daily water resources for any Julian date to the yearly maximum values over climatological period, it detected flood starting date (for FI > 0) and represented adequately anomalously high precipitation that potentially triggered flood situation. The severity, intensity and durations were analysed by running sum approach of [9] over identified flood periods between onset and termination dates. Our results demonstrated good skill of the daily Flood Index for objective diagnosis and monitoring of flood events based on water intensive properties. The method allowed for the detection of the event, and quantified its properties for comparison of various events. The method was novel for quantifying floods and appears quite promising for forecasting flood events using time-series approaches
Folateâconjugated thermoâresponsive micelles for tumor targeting
Folateâconjugated and thermoâresponsive poly(( N âisopropylacrylamide)â co â acrylamideâ co â(octadecyl acrylate)â co â(folateâ(polyethylene glycol)â(acrylic acid))) (P(NIPAâ co âAAmâ co âODAâ co âFPA)) micelles with mean diameter of about 60 nm and lower critical solution temperature (LCST) of about 39°C were synthesized by free radical random copolymerization. Singleâfactor tests of acrylamide and octadecyl acrylate were carried out to modulate micelles' LCST and diameter, respectively. LCST, diameter, and morphology of micelles were determined by UVâvis spectrophotometer, laser particle size analyzer, and transmittance electron microscope (TEM), respectively. Fluorescein was then used as a model drug to investigate the drug loading content of micelles. Micelles with maximum amount of octadecyl acrylate (180 mg) were found to yield drug loading content of 10.48%. Near infrared dye No.10 was chosen as the tracer to monitor micelles in vivo . The targeting behaviors of micelles in folate receptor positive Belâ7402 tumor bearing nude mice were assessed by a selfâconstructed near infrared imaging system. Results showed satisfactory targeting capability of the thermoâresponsive micelles toward Belâ7402 tumors, and targeting accumulation could last for more than 96 h, enabling P(NIPAâ co âAAmâ co âODAâ co âFPA) micelles to function as a diagnostic reagent as well as a targeted tumor therapy. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3134â3142, 2012.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93660/1/34230_ftp.pd
Constraining Galileon inflation
In this short paper, we present constraints on the Galileon inflationary model from the CMB bispectrum. We employ a principal-component analysis of the independent degrees of freedom constrained by data and apply this to the WMAP 9-year data to constrain the free parameters of the model. A simple Bayesian comparison establishes that support for the Galileon model from bispectrum data is at best weak
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