Gauge Coupling Unification in E6 F-Theory GUTs with Matter and Bulk Exotics from Flux Breaking

We consider gauge coupling unification in E6 F-Theory Grand Unified Theories (GUTs) where E6 is broken to the Standard Model (SM) gauge group using fluxes. In such models there are two types of exotics that can affect gauge coupling unification, namely matter exotics from the matter curves in the 27 dimensional representation of E6 and the bulk exotics from the adjoint 78 dimensional representation of E6. We explore the conditions required for either the complete or partial removal of bulk exotics from the low energy spectrum. In the latter case we shall show that (miraculously) gauge coupling unification may be possible even if there are bulk exotics at the TeV scale. Indeed in some cases it is necessary for bulk exotics to survive to the TeV scale in order to cancel the effects coming from other TeV scale matter exotics which would by themselves spoil gauge coupling unification. The combination of matter and bulk exotics in these cases can lead to precise gauge coupling unification which would not be possible with either type of exotics considered by themselves. The combination of matter and bulk exotics at the TeV scale represents a unique and striking signature of E6 F-theory GUTs that can be tested at the LHC.Comment: 21 pages, 5 figure

Multi-filter spectrophotometry simulations

To complement both the multi-filter observations of quasar environments described in these proceedings, as well as the proposed UBC 2.7 m Liquid Mirror Telescope (LMT) redshift survey, we have initiated a program of simulated multi-filter spectrophotometry. The goal of this work, still very much in progress, is a better quantitative assessment of the multiband technique as a viable mechanism for obtaining useful redshift and morphological class information from large scale multi-filter surveys

Left Ventricular Mass in Physically Active Adults with a Family History of Hypertension

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Factors enhancing mobile technology acceptance: A case study of 15 teachers in a Pretoria secondary school

While a considerable body of research has focused on learners’ acceptance of or resistance to mobile technologies, fewer studies have focused on teachers. This research study aimed to understand the factors influencing South African teachers’ acceptance of or resistance to using mobile technologies in their classroom practice. The Technology Acceptance Model (TAM) was used as a lens to explore factors that enhance mobile technology acceptance. The study consisted of a sequential mixed method, action research approach. Fifteen participants received training at a Mobile Technology workshop, aiming to provide professional development and enhance technological literacy knowledge and skills for teachers. The participants were then tasked to teach with technology and to share and reflect on their experiences and perceptions during the community of practice meetings. Content analysis was used to analyse the transcripts of these meetings and this led to the identification of 2 key factors, which enhanced the teachers’ acceptance of mobile technology, namely, perceived usefulness and perceived ease of use. Six sub-factors affecting acceptance were also identified: anxiety, ability, attitude, facilitating conditions, subjective norm and voluntariness. The factors that were identified suggest that additional professional development, infrastructure and resources need to be provided for teachers. We argue that by providing these necessities and eliminating or significantly reducing these factors, the use of mobile technology will be a success. Keywords: improving classroom teaching; interactive learning environments; learning communities; mobile technology acceptance; secondary education; teaching/learning strategie

Biophysically motivated efficient estimation of the spatially isotropic R*2 component from a single gradient‐recalled echo measurement

Purpose To propose and validate an efficient method, based on a biophysically motivated signal model, for removing the orientation‐dependent part of R*2 using a single gradient‐recalled echo (GRE) measurement. Methods The proposed method utilized a temporal second‐order approximation of the hollow‐cylinder‐fiber model, in which the parameter describing the linear signal decay corresponded to the orientation‐independent part of R*2. The estimated parameters were compared to the classical, mono‐exponential decay model for R*2 in a sample of an ex vivo human optic chiasm (OC). The OC was measured at 16 distinct orientations relative to the external magnetic field using GRE at 7T. To show that the proposed signal model can remove the orientation dependence of R*2, it was compared to the established phenomenological method for separating R*2 into orientation‐dependent and ‐independent parts. Results Using the phenomenological method on the classical signal model, the well‐known separation of R*2 into orientation‐dependent and ‐independent parts was verified. For the proposed model, no significant orientation dependence in the linear signal decay parameter was observed. Conclusions Since the proposed second‐order model features orientation‐dependent and ‐independent components at distinct temporal orders, it can be used to remove the orientation dependence of R*2 using only a single GRE measurement

Management of intracranial surgery for refractory epilepsy in severe factor VII deficiency: choosing the optimal dosing regimen

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106864/1/hae12397.pd

Antiferromagnetic Order in Disorder-Induced Insulating Phase of SrRu_{1-x}Mn_xO_3 (0.4<x<0.6)

We have performed the powder neutron diffraction measurements on the solid solutions of SrRu_{1-x}Mn_xO_3, and found that the itinerant ferromagnetic order observed in pure SrRuO_3 changes into the C-type antiferromagnetic (AF) order with nearly localized d electrons in the intermediate Mn concentration between x=0.4 and 0.6. With increasing x, the AF moment is strongly enhanced from 1.1 mB (x=0.4) to 2.6 mB (x=0.6), which is accompanied by the elongation of the tetragonal c/a ratio. These results suggest that the substitution of Mn for Ru suppresses the itinerant character of the d electrons, and induces the superexchange interaction through the compression in the c plane. We have also found that the magnetic and transport properties observed in our tetragonal samples are quite similar to those of recently reported orthorhombic ones.Comment: 4 pages, 4 figure

Is subarctic forest advance able to keep pace with climate change?

Recent climate warming and scenarios for further warming have led to expectations of rapid movement of ecological boundaries. Here we focus on the circumarctic forest-tundra ecotone (FTE), which represents an important bioclimatic zone with feedbacks from forest advance and corresponding tundra disappearance (up to 50% loss predicted this century) driving widespread ecological and climatic changes. We address FTE advance and climate history relations over the 20th century, using FTE response data from 151 sites across the circumarctic area and site-specific climate data. Specifically, we investigate spatial uniformity of FTE advance, statistical associations with 20th century climate trends, and whether advance rates match climate change velocities (CCVs). Study sites diverged into four regions (Eastern Canada; Central and Western Canada and Alaska; Siberia; and Western Eurasia) based on their climate history, although all were characterized by similar qualitative patterns of behaviour (with about half of the sites showing advancing behaviour). The main associations between climate trend variables and behaviour indicate the importance of precipitation rather than temperature for both qualitative and quantitative behaviours, and the importance of non-growing season as well as growing season months. Poleward latitudinal advance rates differed significantly among regions, being smallest in Eastern Canada (~10 m/year) and largest in Western Eurasia (~100 m/year). These rates were 1-2 orders of magnitude smaller than expected if vegetation distribution remained in equilibrium with climate. The many biotic and abiotic factors influencing FTE behaviour make poleward advance rates matching predicted 21st century CCVs (~103 -104  m/year) unlikely. The lack of empirical evidence for swift forest relocation and the discrepancy between CCV and FTE response contradict equilibrium model-based assumptions and warrant caution when assessing global-change-related biotic and abiotic implications, including land-atmosphere feedbacks and carbon sequestration.Funding was provided by the Norwegian Research Council (grants 176065/S30, 185023/S50, 160022/F40 and 244557/RI), the Government of Canada Program for International Polar Year, the US National Science Foundation, and the University of Cambridge

The value of tibial mounted inertial measurement units to quantify running kinetics in elite football (soccer) players. A reliability and agreement study using a research orientated and a clinically orientated system

In elite football, measurement of running kinetics with inertial measurement units (IMUs) may be useful as a component of periodic health examination (PHE). This study determined the reliability of, and agreement between a research orientated IMU and clinically orientated IMU system for initial peak acceleration (IPA) and IPA symmetry index (SI) measurement during running in elite footballers. On consecutive days, 16 participants performed treadmill running at 14kmph and 18kmph. Both IMUs measured IPA and IPA SI concurrently. All measurements had good or excellent within-session reliability (intraclass correlation coefficient (ICC2,1) range = 0.79-0.96, IPA standard error of measurement (SEM) range = 0.19-0.62 g, IPA SI SEM range = 2.50-8.05%). Only the research orientated IMU demonstrated acceptable minimal detectable changes (MDCs) for IPA at 14kmph (range = 7.46-9.80%) and IPA SI at both speeds (range = 6.92-9.21%). Considering both systems, between-session IPA reliability ranged from fair to good (ICC2,1 range = 0.63-0.87, SEM range = 0.51-1.10 g) and poor to fair for IPA SI (ICC2,1 range = 0.32-0.65, SEM range = 8.07-11.18%). All MDCs were >10%. For IPA and SI, the 95% levels of agreement indicated poor between system agreement. Therefore, the use of IMUs to evaluate treadmill running kinetics cannot be recommended in this population as a PHE test to identify prognostic factors for injuries or for rehabilitation purposes