Effects of the Lattice Discreteness on a Soliton in the Su-Schrieffer-Heeger Model

In this paper we analytically study the effects of the lattice discreteness on the electron band in the SSH model. We propose a modified version of the TLM model which is derived from the SSH model using a continuum approximation. When a soliton is induced in the electron-lattice system, the electron scattering states both at the bottom of the valence band and the top of the conduction band are attracted to the soliton. This attractive force induces weakly localized electronic states at the band edges. Using the modified version of the TLM model, we have succeeded in obtaining analytical solutions of the weakly localized states and the extended states near the bottom of the valence band and the top of the conduction band. This band structure does not modify the order parameters. Our result coincides well with numerical simulation works.Comment: to be appear in J.Phys.Soc.Jpn. Figures should be requested to the author. They will be sent by the conventional airmai

Emerging from the third space chrysalis: Experiences in a non-hierarchical, collaborative research community of practice

This article discusses the creation of a research-focused virtual community of practice (vCoP) for geographically-dispersed third space professionals, motivated by desires for enhanced professional collaboration, visibility and identity. The authors used collaborative autoethnography (CAE) to evaluate their personal reflections as vCoP participants. Data were gathered in two collaborative writing activities and analysed using thematic analysis (TA). The TA identified two connected themes, which capture the vCoP members’ aspirations to transcend their current roles and be research-active through connecting with like-minded professionals. Collaborative writing activities, including authoring this paper, cultivated elements of academic identity such as independence and purpose. A non-hierarchical and supportive vCoP environment allowed the members to work beyond time and institutional constraints to foster the evolution of the community and an emerging sense of professional identity beyond that typically associated with third space roles. The paper offers a model of collaboration that could help groups in similar situations

A combined computational and experimental investigation of the [2Fe–2S] cluster in biotin synthase

Biotin synthase was the first example of what is now regarded as a distinctive enzyme class within the radical S-adenosylmethionine superfamily, the members of which use Fe/S clusters as the sulphur source in radical sulphur insertion reactions. The crystal structure showed that this enzyme contains a [2Fe–2S] cluster with a highly unusual arginine ligand, besides three normal cysteine ligands. However, the crystal structure is at such a low resolution that neither the exact coordination mode nor the role of this exceptional ligand has been elucidated yet, although it has been shown that it is not essential for enzyme activity. We have used quantum refinement of the crystal structure and combined quantum mechanical and molecular mechanical calculations to explore possible coordination modes and their influences on cluster properties. The investigations show that the protonation state of the arginine ligand has little influence on cluster geometry, so even a positively charged guanidinium moiety would be in close proximity to the iron atom. Nevertheless, the crystallised enzyme most probably contains a deprotonated (neutral) arginine coordinating via the NH group. Furthermore, the Fe···Fe distance seems to be independent of the coordination mode and is in perfect agreement with distances in other structurally characterised [2Fe–2S] clusters. The exceptionally large Fe···Fe distance found in the crystal structure could not be reproduced

Parity Violation in Proton-Proton Scattering at 221 MeV

TRIUMF experiment 497 has measured the parity violating longitudinal analyzing power, A_z, in pp elastic scattering at 221.3 MeV incident proton energy. This paper includes details of the corrections, some of magnitude comparable to A_z itself, required to arrive at the final result. The largest correction was for the effects of first moments of transverse polarization. The addition of the result, A_z=(0.84 \pm 0.29 (stat.) \pm 0.17 (syst.)) \times 10^{-7}, to the pp parity violation experimental data base greatly improves the experimental constraints on the weak meson-nucleon coupling constants h^{pp}_\rho and h^{pp}_\omega, and has implications for the interpretation of electron parity violation experiments.Comment: 17 pages RevTeX, 14 PostScript figures. Revised version with additions suggested by Phys. Rev.

Parity Violation in Proton-Proton Scattering at 221 MeV

The parity-violating longitudinal analyzing power, Az, has been measured in pp elastic scattering at an incident proton energy of 221 MeV. The result obtained is Az =(0.84 +/- 0.29 (stat.) +/- 0.17 (syst.)) x 10^{-7}. This experiment is unique in that it selects a single parity violating transition amplitude, 3P2-1D2, and consequently directly constrains the weak meson-nucleon coupling constant h^pp_rho When this result is taken together with the existing pp parity violation data, the weak meson-nucleon coupling constants h^pp_rho and h^pp_omega can, for the first time, both be determined.Comment: 8 pages RevTeX4, 3 PostScript figures. Conclusion revised. New information about weak coupling constants adde

Contribution of DEAF1 Structural Domains to the Interaction with the Breast Cancer Oncogene LMO4

The proteins LMO4 and DEAF1 contribute to the proliferation of mammary epithelial cells. During breast cancer LMO4 is upregulated, affecting its interaction with other protein partners. This may set cells on a path to tumour formation. LMO4 and DEAF1 interact, but it is unknown how they cooperate to regulate cell proliferation. In this study, we identify a specific LMO4-binding domain in DEAF1. This domain contains an unstructured region that directly contacts LMO4, and a coiled coil that contains the DEAF1 nuclear export signal (NES). The coiled coil region can form tetramers and has the typical properties of a coiled coil domain. Using a simple cell-based assay, we show that LMO4 modulates the activity of the DEAF NES, causing nuclear accumulation of a construct containing the LMO4-interaction region of DEAF1

Marx’s "Capital"in the Information Age

This article argues that a media and communication studies perspective on reading Marx’s Capital has thus far been missing, but is needed in the age of information capitalism and digital capitalism. Two of the most popular contemporary companions to Marx’s Capital, the ones by David Harvey and Michael Heinrich, present themselves as general guidebooks on how to read Marx, but are actually biased towards particular schools of Marxist thought. A contemporary reading of Marx needs to be mediated with contemporary capitalism’s structures and the political issues of the day. Media, communications and the Internet are important issues for such a reading today. It is time to see Marx not just as a critic of capitalism but also as a critic of capitalist communications

In patient stroke rehabilitation efficiency: Influence of organization of service delivery and staff numbers

<p>Abstract</p> <p>Background</p> <p>Outcomes of inpatient stroke rehabilitation need to be reviewed in terms of optimal resource utilization (staff time, service organization, and duration of stay). We compared FIM efficiency scores between three hospitals, and also variation in FIM scores over a ten year period in one hospital undergoing reduction in staff numbers, to examine the relationship between outcome and service characteristics.</p> <p>Method</p> <p>This is a retrospective study comparing the mean FIM efficiency for stroke patients (FIM score – FIM admission score) divided by duration of stay for 2005 among three rehabilitation hospitals adjusting for age and baseline FIM score, and a longitudinal study of changes in mean FIM efficiency during a ten year period in one hospital, to examine the effects of different service organization and staff numbers.</p> <p>Results</p> <p>FIM efficiency (FIMEG) was inversely associated with age, and positively associated with admission FIM score. FIMEG was higher in the hospital with a coordinated care plan involving medical, nursing, occupational, physiotherapy staff and other healthcare providers working as a team, with a seamless interface with community rehabilitation services. Over a ten year period, reduction in staff numbers was associated with reduction in FIMEG, which may be offset to some extent by service re-engineering.</p> <p>Conclusion</p> <p>Within hospital organization of stroke rehabilitation services may influence outcome. A critical number of staff may be identified for the provision of services, below which rehabilitation efficiency may be affected.</p

Problematic online behaviors among adolescents and emerging adults: associations between cyberbullying perpetration, problematic social media use, and psychosocial factors

Over the past two decades, young people's engagement in online activities has grown markedly. The aim of the present study was to examine the relationship between two specific online behaviors (i.e., cyberbullying perpetration, problematic social media use) and their relationships with social connectedness, belongingness, depression, and self-esteem among high school and university students. Data were collected from two different study groups via two questionnaires that included the Cyberbullying Offending Scale, Social Media Use Questionnaire, Social Connectedness Scale, General Belongingness Scale, Short Depression-Happiness Scale, and Single Item Self-Esteem Scale. Study 1 comprised 804 high school students (48% female; mean age 16.20 years). Study 2 comprised 760 university students (60% female; mean age 21.48 years). Results indicated that problematic social media use and cyberbullying perpetration (which was stronger among high school students) were directly associated with each other. Belongingness (directly) and social connectedness (indirectly) were both associated with cyberbullying perpetration and problematic social media use. Path analysis demonstrated that while age was a significant direct predictor of problematic social media use and cyberbullying perpetration among university students, it was not significant among high school students. In both samples, depression was a direct predictor of problematic social media use and an indirect predictor of cyberbullying perpetration. However, majority of these associations were relatively weak. The present study significantly adds to the emerging body of literature concerning the associations between problematic social media use and cyberbullying perpetration

Oncogenic Stress Induced by Acute Hyper-Activation of Bcr-Abl Leads to Cell Death upon Induction of Excessive Aerobic Glycolysis

In response to deregulated oncogene activation, mammalian cells activate disposal programs such as programmed cell death. To investigate the mechanisms behind this oncogenic stress response we used Bcr-Abl over-expressing cells cultivated in presence of imatinib. Imatinib deprivation led to rapid induction of Bcr-Abl activity and over-stimulation of PI3K/Akt-, Ras/MAPK-, and JAK/STAT pathways. This resulted in a delayed necrosis-like cell death starting not before 48 hours after imatinib withdrawal. Cell death was preceded by enhanced glycolysis, glutaminolysis, and amino acid metabolism leading to elevated ATP and protein levels. This enhanced metabolism could be linked to induction of cell death as inhibition of glycolysis or glutaminolysis was sufficient to sustain cell viability. Therefore, these data provide first evidence that metabolic changes induced by Bcr-Abl hyper-activation are important mediators of oncogenic stress-induced cell death