Heterotic free fermionic and symmetric toroidal orbifold models

Free fermionic models and symmetric heterotic toroidal orbifolds both constitute exact backgrounds that can be used effectively for phenomenological explorations within string theory. Even though it is widely believed that for Z2xZ2 orbifolds the two descriptions should be equivalent, a detailed dictionary between both formulations is still lacking. This paper aims to fill this gap: We give a detailed account of how the input data of both descriptions can be related to each other. In particular, we show that the generalized GSO phases of the free fermionic model correspond to generalized torsion phases used in orbifold model building. We illustrate our translation methods by providing free fermionic realizations for all Z2xZ2 orbifold geometries in six dimensions.Comment: 1+49 pages latex, minor revisions and references adde

Using Network Analysis to Understand Knowledge Mobilization in a Community-based Organization

Background Knowledge mobilization (KM) has been described as putting research in the hands of research users. Network analysis is an empirical approach that has potential for examining the complex process of knowledge mobilization within community-based organizations (CBOs). Yet, conducting a network analysis in a CBO presents challenges. Purpose The purpose of this paper is to demonstrate the value and feasibility of using network analysis as a method for understanding knowledge mobilization within a CBO by (1) presenting challenges and solutions to conducting a network analysis in a CBO, (2) examining the feasibility of our methodology, and (3) demonstrating the utility of this methodology through an example of a network analysis conducted in a CBO engaging in knowledge mobilization activities. Method The final method used by the partnership team to conduct our network analysis of a CBO is described. Results An example of network analysis results of a CBO engaging in knowledge mobilization is presented. In total, 81 participants completed the network survey. All of the feasibility benchmarks set by the CBO were met. Results of the network analysis are highlighted and discussed as a means of identifying (1) prominent and influential individuals in the knowledge mobilization process and (2) areas for improvement in future knowledge mobilization initiatives. Conclusion Findings demonstrate that network analysis can be feasibly used to provide a rich description of a CBO engaging in knowledge mobilization activities

The psychological reality of spatio-temporal metaphors

Time provides essential structure to human experience. In this chapter we review the available empirical evidence for a fundamental metaphoric structure such as TIME IS SPACE in figurative language and thought. The chapter is organized into three over-arching themes: Motion through time, that is, the influence of ego-moving metaphors (motion of the observer’s context along a timeline) and time-moving metaphors (motion of events along a timeline) on the construal of time as moving or stationary; Temporal succession, and how it is conceptualized on the specific spatial axes (horizontal and/or vertical) used to sequence events in time; and lastly, temporal duration, focusing on the metaphors used to describe the temporal extension of an event and their influence on the perception of duration. A large part of the experimental evidence lends support to the psychological reality of the TIME IS SPACE metaphor, revealing the inextricable link between conceptual metaphor in language and fundamental thinking processes like perception of temporal succession and time estimation, contributing to the emerging broader picture of the powerful role of linguistic experience in shaping the way conceptual representations are formed and activated. At the same time, the review also reveals that linguistic space-time mappings may be overridden by cultural conventions. Taken together, the evidence available to date suggests that the mental representation of time in humans is the outcome of an intricate interplay between linguistic (i.e. metaphors) and cultural factors, calling for further exploration of this interplay through empirical research

Illuminating ATOM: Taking time across the colour category border

Walsh’s A Theory Of Magnitude (ATOM) contends that we represent magnitudes such as number, space, time and luminance on a shared metric, such that ‘more’ of one leads to the perception of ‘more’ of the other (e.g. Walsh, 2003). In support of ATOM, participants have been shown to judge intervals between stimuli that are more discrepant in luminance as having a longer duration than intervals between stimuli whose luminance differs by a smaller degree (Xuan, Zhang, He, & Chen, 2007). We tested the potential limits to the ability of luminance to influence duration perception by investigating the possibility that the luminance-duration relationship might be interrupted by a concurrent change in the colour of that luminance. We showed native Greek and native English speakers sequences of stimuli that could be either light or dark versions of green or blue. Whereas for both groups a shift in green luminance does not comprise a categorical shift in colour, for Greek speakers shifts between light and dark blue cross a colour category boundary (ghalazio and ble respectively). We found that duration judgements were neither interrupted nor inflated by a shift in colour category. These results represent the first evidence that the influence of luminance change on duration perception is resistant to interference from discrete changes within the same perceptual input

CoBiToM Project -- II: Evolution of contact binary systems close to the orbital period cut-off

Ultra-short orbital period contact binaries (Porb < 0.26 d) host some of the smallest and least massive stars. These systems are faint and rare, and it is believed that they have reached a contact configuration after several Gyrs of evolution via angular momentum loss, mass transfer and mass loss through stellar wind processes. This study is conducted in the frame of Contact Binaries Towards Merging (CoBiToM) Project and presents the results from light curve and orbital analysis of 30 ultra-short orbital period contact binaries, with the aim to investigate the possibility of them being red nova progenitors, eventually producing merger events. Approximately half of the systems exhibit orbital period modulations, as a result of mass transfer or mass loss processes. Although they are in contact, their fill-out factor is low (less than 30 per cent), while their mass ratio is larger than the one in longer period contact binaries. The present study investigates the orbital stability of these systems and examines their physical and orbital parameters in comparison to those of the entire sample of known and well-studied contact binaries, based on combined spectroscopic and photometric analysis. It is found that ultra-short orbital period contact binaries have very stable orbits, while very often additional components are gravitationally bound in wide orbits around the central binary system. We confirmed that the evolution of such systems is very slow, which explains why the components of ultra-short orbital period systems are still Main Sequence stars after several Gyrs of evolution

A wearable motion capture suit and machine learning predict disease progression in Friedreich's ataxia.

Friedreich's ataxia (FA) is caused by a variant of the Frataxin (FXN) gene, leading to its downregulation and progressively impaired cardiac and neurological function. Current gold-standard clinical scales use simplistic behavioral assessments, which require 18- to 24-month-long trials to determine if therapies are beneficial. Here we captured full-body movement kinematics from patients with wearable sensors, enabling us to define digital behavioral features based on the data from nine FA patients (six females and three males) and nine age- and sex-matched controls, who performed the 8-m walk (8-MW) test and 9-hole peg test (9 HPT). We used machine learning to combine these features to longitudinally predict the clinical scores of the FA patients, and compared these with two standard clinical assessments, Spinocerebellar Ataxia Functional Index (SCAFI) and Scale for the Assessment and Rating of Ataxia (SARA). The digital behavioral features enabled longitudinal predictions of personal SARA and SCAFI scores 9 months into the future and were 1.7 and 4 times more precise than longitudinal predictions using only SARA and SCAFI scores, respectively. Unlike the two clinical scales, the digital behavioral features accurately predicted FXN gene expression levels for each FA patient in a cross-sectional manner. Our work demonstrates how data-derived wearable biomarkers can track personal disease trajectories and indicates the potential of such biomarkers for substantially reducing the duration or size of clinical trials testing disease-modifying therapies and for enabling behavioral transcriptomics

Flexing gender perception:Brain potentials reveal the cognitive permeability of grammatical information

A growing body of recent research suggests that verbal categories, particularly labels, impact categorization and perception. These findings are commonly interpreted as demonstrating the involvement of language on cognition, however, whether these assumptions hold true for grammatical structures has yet to be investigated. In the present study, we investigated the extent to which linguistic information, namely, grammatical gender categories structures cognition to subsequently influence categorical judgments and perception. In a non-verbal categorization task, French-English bilinguals and monolingual English speakers made gender-associated judgments about a set of image pairs while event-related potentials were recorded. The image sets were composed of an object paired with either a female or male face, wherein the object was manipulated for their conceptual gender relatedness and grammatical gender congruency to the sex of the following target face. The results showed that grammatical gender modulated the N1 and P2/VPP, as well as the N300 exclusively for the French-English bilinguals, indicating the inclusion of language in the mechanisms associated with attentional bias and categorization. In contrast, conceptual gender information impacted the monolingual English speakers in the later N300 time window given the absence of a comparable grammatical feature. Such effects of grammatical categories in the early perceptual stream have not been found before, and further provide grounds to suggest that language shapes perception

CoBiToM project - I. Contact binaries towards merging

Binary and multiple stellar systems are numerous in our solar neighbourhood with 80per cent of the solar-type stars being members of systems with high order multiplicity. The Contact Binaries Towards Merging (CoBiToM) Project is a programme that focuses on contact binaries and multiple stellar systems, as a key for understanding stellar nature. The goal is to investigate stellar coalescence and merging processes, as the final state of stellar evolution of low-mass contact binary systems. Obtaining observational data of approximately 100 eclipsing binaries and multiple systems and more than 400 archival systems, the programme aspires to give insights for their physical and orbital parameters and their temporal variations, e.g. the orbital period modulation, spot activity etc. Gravitational phenomena in multiple-star environments will be linked with stellar evolution. A comprehensive analysis will be conducted, in order to investigate the possibility of contact binaries to host planets, as well as the link between inflated hot Jupiters and stellar mergers. The innovation of CoBiToM Project is based on a multimethod approach and a detailed investigation, that will shed light for the first time on the origin of stellar mergers and rapidly rotating stars. In this work, we describe the scientific rationale, the observing facilities to be used and the methods that will be followed to achieve the goals of CoBiToM Project and we present the first results as an example of the current research on evolution of contact binary systems