3,289 research outputs found
Arguments towards the construction of a matrix model groundstate
We discuss the existence and uniqueness of wavefunctions for inhomogenoeus
boundary value problems associated to x^2y^2-type matrix model on a bounded
domain of R^2. Both properties involve a combination of the Cauchy-Kovalewski
Theorem and a explicit calculations.Comment: 3 pages, Latex Proceedings for the XIX Simposio Chileno de Fisica,
SOCHIFI 2014 Conference, 26-28 November 2014, held at Concepcion U., Chil
The supermembrane with central charges:(2+1)-D NCSYM, confinement and phase transition
The spectrum of the bosonic sector of the D=11 supermembrane with central
charges is shown to be discrete and with finite multiplicities, hence
containing a mass gap. The result extends to the exact theory our previous
proof of the similar property for the SU(N) regularised model and strongly
suggest discreteness of the spectrum for the complete Hamiltonian of the
supermembrane with central charges. This theory is a quantum equivalent to a
symplectic non-commutative super-Yang-Mills in 2+1 dimensions, where the
space-like sector is a Riemann surface of positive genus. In this context, it
is argued how the theory in 4D exhibits confinement in the N=1 supermembrane
with central charges phase and how the theory enters in the quark-gluon plasma
phase through the spontaneous breaking of the centre. This phase is interpreted
in terms of the compactified supermembrane without central charges.Comment: 33 pages, Latex. In this new version, several changes have been made
and various typos were correcte
On the groundstate of octonionic matrix models in a ball
In this work we examine the existence and uniqueness of the groundstate of a
SU(N)x G2 octonionic matrix model on a bounded domain of R^N. The existence and
uniqueness argument of the groundstate wavefunction follows from the
Lax-Milgram theorem. Uniqueness is shown by means of an explicit argument which
is drafted in some detail.Comment: Latex, 6 page
Massless ground state for a compact SU(2) matrix model in 4D
We show the existence and uniqueness of a massless supersymmetric ground
state wavefunction of a SU(2) matrix model in a bounded smooth domain with
Dirichlet boundary conditions. This is a gauge system and we provide a new
framework to analyze the quantum spectral properties of this class of
supersymmetric matrix models subject to constraints which can be generalized
for arbitrary number of colors.Comment: 12 pages, Latex. Somme clarifications. Minor changes. Version to
appear at NP
The ground state of the D=11 supermembrane and matrix models on compact regions
We establish a general framework for the analysis of boundary value problems
of matrix models at zero energy on compact regions. We derive existence and
uniqueness of ground state wavefunctions for the mass operator of the
regularized supermembrane theory, that is the supersymmetric
matrix model, on balls of finite radius. Our results rely on the
structure of the associated Dirichlet form and a factorization in terms of the
supersymmetric charges. They also rely on the polynomial structure of the
potential and various other supersymmetric properties of the system.Comment: Latex, 26 pages. We have added some comments at the introduction in
order to make it easier for the reader. Results of the paper unchange
Social Sensing of Floods in the UK
"Social sensing" is a form of crowd-sourcing that involves systematic
analysis of digital communications to detect real-world events. Here we
consider the use of social sensing for observing natural hazards. In
particular, we present a case study that uses data from a popular social media
platform (Twitter) to detect and locate flood events in the UK. In order to
improve data quality we apply a number of filters (timezone, simple text
filters and a naive Bayes `relevance' filter) to the data. We then use place
names in the user profile and message text to infer the location of the tweets.
These two steps remove most of the irrelevant tweets and yield orders of
magnitude more located tweets than we have by relying on geo-tagged data. We
demonstrate that high resolution social sensing of floods is feasible and we
can produce high-quality historical and real-time maps of floods using Twitter.Comment: 24 pages, 6 figure
On the spectrum of a matrix model for the D=11 supermembrane compactified on a torus with non-trivial winding
The spectrum of the Hamiltonian of the double compactified D=11 supermembrane
with non-trivial central charge or equivalently the non-commutative symplectic
super Maxwell theory is analyzed. In distinction to what occurs for the D=11
supermembrane in Minkowski target space where the bosonic potential presents
string-like spikes which render the spectrum of the supersymmetric model
continuous, we prove that the potential of the bosonic compactified membrane
with non-trivial central charge is strictly positive definite and becomes
infinity in all directions when the norm of the configuration space goes to
infinity. This ensures that the resolvent of the bosonic Hamiltonian is
compact. We find an upper bound for the asymptotic distribution of the
eigenvalues.Comment: 11 pages, LaTe
Does authentic self-esteem buffer the negative effects of bullying victimization on social anxiety and classroom concentration? Evidence from a short-term longitudinal study with early adolescents
Background
Bullying victimization is a risk factor for social anxiety and disrupted classroom concentration among young people. Self-esteem has been implicated as a protective factor, but extant literature is sparse.
Aims
Aim of present study was to test if a new measure of authentic self-esteem can buffer the negative effects of bullying victimization on social anxiety and disrupted classroom concentration concurrently and across time.
Sample
A short-term longitudinal questionnaire design was employed with 836 12- and 13-year-olds.
Methods
Peer nominations of bullying victimization and self-reports of authentic self-esteem were collected during winter term, and self-reports of social anxiety and disrupted classroom concentration were solicited then and also 5 months later.
Results
Hierarchical multiple regression models indicated that authentic self-esteem moderated the association between bullying victimization and (i) social anxiety both concurrently and longitudinally and (ii) disrupted classroom concentration longitudinally. The Johnson-Neyman technique identified where on its scale authentic self-esteem had its buffering effects, and these were found to be at relatively low or moderate levels.
Conclusions
Even moderate levels of authentic self-esteem can mitigate the association between being bullied and (i) social anxiety and (ii) disrupted classroom concentration. Efforts to monitor and where necessary enhance the authentic self-esteem of young people are warranted
Parenting about challenges and adolescents' social anxiety, disrupted classroom concentration and resilience knowledge: the mediating role of authentic self-esteem
A large theoretical and empirical literature indicates that parenting practices affect young people’s well-being and resilience, but there is much still to learn about psychological mechanisms, especially beyond infancy/early childhood. A recent model of authentic self-esteem argues that it arises out of experiences of challenge situations shared with parents and that it can subsequently act as a protective factor that supports well-being and resilience among young people. The aim of the current study is to test: (i) if parenting about challenges can predict three indices of adolescents’ well-being, namely their (a) social anxiety, (b) disrupted classroom concentration, and (c) ability to spontaneously generate resilient strategies, and more substantially (ii) if authentic self-esteem can mediate those associations if found.
Adolescents (N = 836) completed a questionnaire that measured all of the study variables via self-report with the exception that unprompted open questions were used to gauge their ability to spontaneously generate resilient strategies.
Parental discussions of challenges did significantly predict all three well-being indices, and authentic self-esteem was found to mediate all of these relationships.
These results support the view that parenting about challenges is a practice that supports well-being and resilience in adolescents. It appears to do so through promoting the development of authentic self-esteem, a capacity to evaluate the self in a positive manner in the context of challenges. The theoretical and practical significance of these findings are discussed
Helping School Students Deal with Peer Provocations and Avoid Hostile Attribution Bias with the CATZ Cross-Age Teaching Zone Intervention
Cross-age tutoring and co-operative group work have been shown to help student tutors and tutees acquire academic and non-academic skills and knowledge. A novel intervention (Cross-Age Teaching Zone, CATZ) that combined them was tested for its effects on student tutors’ thinking skills associated with (i) dealing pro-socially with peer provocations and (ii) avoiding hostile attribution bias. Small co-operative groups of 11- and 15-year-old students (N = 228) designed a CATZ lesson on these themes and delivered it to younger students. The CATZ tutors, but not matched controls (N = 189), showed significant improvements on both outcome measures. Participants aged 9 to 15 years (N = 469) were also asked about: (1) their willingness to act as CATZ tutors/tutees, (2) how effective they think such CATZ activities would be, (3) how much they valued autonomy in how they might deliver CATZ, and (4) their relative preference for being taught by older students versus teachers. Overall, participants expressed positive views of CATZ, which also helped students learn patterns of thinking that can help them avoid aggressive and conflict behavior. This initial evidence on the effectiveness of CATZ calls for further research to use CATZ across a range of social, emotional, and behavioral domains to support its wider uptake in schools
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