Rouse Modes of Self-avoiding Flexible Polymers

Using a lattice-based Monte Carlo code for simulating self-avoiding flexible polymers in three dimensions in the absence of explicit hydrodynamics, we study their Rouse modes. For self-avoiding polymers, the Rouse modes are not expected to be statistically independent; nevertheless, we demonstrate that numerically these modes maintain a high degree of statistical independence. Based on high-precision simulation data we put forward an approximate analytical expression for the mode amplitude correlation functions for long polymers. From this, we derive analytically and confirm numerically several scaling properties for self-avoiding flexible polymers, such as (i) the real-space end-to-end distance, (ii) the end-to-end vector correlation function, (iii) the correlation function of the small spatial vector connecting two nearby monomers at the middle of a polymer, and (iv) the anomalous dynamics of the middle monomer. Importantly, expanding on our recent work on the theory of polymer translocation, we also demonstrate that the anomalous dynamics of the middle monomer can be obtained from the forces it experiences, by the use of the fluctuation-dissipation theorem.Comment: 16 pages (double spaced), 5 figures, small changes and corrections, to appear in J. Chem. Phy

Who Are the “Middle Class”?

There is no consensus definition of middle class, neither is there an official government definition. What constitutes the middle class is relative, subjective, and not easily defined. The mid-point in the distribution is the median, and in 2007 the median household income was $50,233. How far above and below that amount the middle stretches remains an open question. The U.S. Census Bureau has published figures for 2007 breaking the income distribution into quintiles, or fifths. The narrowest view of who might be considered middle class based on that presentation would include those in the middle quintile, which includes households with income between$39,100 and $62,000. A more generous definition might be based on the three middle quintiles, those households with income between$20,291 and $100,000. Surveys suggest that from 1$250,000. Similarly, survey responses suggest that the lower end of the middle class might be close to $40,000

Navigating the Middle Grades and Preparing Students for High School Graduation

This brief presents preliminary findings from an exploratory study of New York City students' transitions into, through, and out of the middle grades. Our analysis reveals that students' attendance and achievement in their early schooling (fourth grade) predict whether students are likely to graduate from high school many years later. Further, we find that many students begin the middle grades on-track to graduate high school but fall off this trajectory before the end of eighth grade. These findings suggest that teachers and administrators should pay close attention to students whose attendance and math achievement fall during the middle grades, as these students are particularly at risk for not graduating from high school on time

Is english our lingua franca or the native speaker's property? The native speaker orientation among middle school students in Japan

This paper reports the first empirical study to date that sought to examine the native speaker orientation among middle school EFL students in Japan. To this end, this preliminary study measured their language attitudes in this respect addressing age-stratified and gender variations. The data was elicited from an attitude survey with 318 eighth and ninth graders at a public middle school. The findings suggest that the students gave the highest evaluations to native than to nonnative varieties of English. Second, they opted for learning English for its currency and utility in the English as a native language setting, rather than for its transnational function as a lingua franca. Lastly, the finding indicated a possible developmental trajectory of their native speaker orientation

Moods of 3-Week and 5-Week Outdoor Expedition Participants

The purpose of this research project was to investigate and document the cycle of mood states displayed by outdoor recreation expedition participants. It was hypothesized that an individual\u27s moods pass through a predictable cycle during the beginning, middle, and end phases of a 3-week to 5-week outdoor expedition.This cycle would include fluctuations in mood states such as anger/hostility, confusion/bewilderment, de­pression/dejection, fatigue, tension/anxiety, and vigor. It was anticipated that ten­sion/anxiety would be high in the beginning, medium to high in the middle, and then low at the end. Depression/dejection was ex­pected to be low in the beginning, high in the middle, and medium to low at the end. Anger/hostility was hypothesized to low in the beginning, high in the middle, and low at the end. Vigor/activity was anticipated to be high in the beginning, low in the middle, and high at the end. It was expected that fa­tigue/inertia would be high in the beginning, low in the middle, and then medium to low at the end. Finally, confusion/bewilderment was predicted to be high in the beginning, then I.ow in the middle and end

An abrupt extinction in the Middle Permian (Capitanian) of the Boreal Realm (Spitsbergen) and its link to anoxia and acidification

The controversial Capitanian (Middle Permian, 262 Ma) extinction event is only known from equatorial latitudes, and consequently its global extent is poorly resolved. We demonstrate that there were two, severe extinctions amongst brachiopods in northern Boreal latitudes (Spitsbergen) in the Middle to Late Permian, separated by a recovery phase. New age dating of the Spitsbergen strata (belonging to the Kapp Starostin Formation), using strontium isotopes and d13C trends and comparison with better-dated sections in Greenland, suggests that the first crisis occurred in the Capitanian. This age assignment indicates that this Middle Permian extinction is manifested at higher latitudes. Redox proxies (pyrite framboids and trace metals) show that the Boreal crisis coincided with an intensification of oxygen depletion, implicating anoxia in the extinction scenario. The widespread and near-total loss of carbonates across the Boreal Realm also suggests a role for acidification in the crisis. The recovery interval saw the appearance of new brachiopod and bivalve taxa alongside survivors, and an increased mollusk dominance, resulting in an assemblage reminiscent of younger Mesozoic assemblages. The subsequent end-Permian mass extinction terminated this Late Permian radiation

Towards an Interaction-based Integration of MKM Services into End-User Applications

The Semantic Alliance (SAlly) Framework, first presented at MKM 2012, allows integration of Mathematical Knowledge Management services into typical applications and end-user workflows. From an architecture allowing invasion of spreadsheet programs, it grew into a middle-ware connecting spreadsheet, CAD, text and image processing environments with MKM services. The architecture presented in the original paper proved to be quite resilient as it is still used today with only minor changes. This paper explores extensibility challenges we have encountered in the process of developing new services and maintaining the plugins invading end-user applications. After an analysis of the underlying problems, I present an augmented version of the SAlly architecture that addresses these issues and opens new opportunities for document type agnostic MKM services.Comment: 14 pages, 7 figure

Formal Verification of an SSA-based Middle-end for CompCert

CompCert is a formally verified compiler that generates compact and efficient PowerPC, ARM and x86 code for a large and realistic subset of the C language. However, CompCert foregoes using Static Single Assignment (SSA), an intermediate representation that allows for writing simpler and faster optimizers, and that is used by many compilers. In fact, it has remained an open problem to verify formally an SSA-based compiler middle-end. We report on a formally verified, SSA-based, middle-end for CompCert. Our middle-end performs conversion from CompCert intermediate form to SSA form, optimization of SSA programs, including Global Value Numbering, and transforming out of SSA to intermediate form. In addition to provide the first formally verified SSA-based middle-end, we address two problems raised by Leroy in 2009: giving a simple and intuitive formal semantics to SSA, and leveraging the global properties of SSA to reason locally about program optimizations