Ensayo de ladrillos a tracción

Not availableEn 1969 se comenzó en la Universidad de Salford un programa de investigación para el ensayo de elementos estructurales de fábrica de ladrillo, bajo los auspicios de la Brick Development Association. El trabajo iba dirigido a determinar la resistencia de los ladrillos bajo las tensiones a que ellos están sometidos en la práctica, que son predominantemente de tracción. Este artículo compara y contrasta los diferentes ensayos de tracción que se investigaron, mientras que un tercer miembro del equipo de investigación describe, en el artículo que continúa, la aplicación de las técnicas de fotoelasticidad a este trabajo

Thermodynamics of C incorporation on Si(100) from ab initio calculations

We study the thermodynamics of C incorporation on Si(100), a system where strain and chemical effects are both important. Our analysis is based on first-principles atomistic calculations to obtain the important lowest energy structures, and a classical effective Hamiltonian which is employed to represent the long-range strain effects and incorporate the thermodynamic aspects. We determine the equilibrium phase diagram in temperature and C chemical potential, which allows us to predict the mesoscopic structure of the system that should be observed under experimentally relevant conditions.Comment: 5 pages, 3 figure

New Tetrahedral Global Minimum for the 98-atom Lennard-Jones Cluster

A new atomic cluster structure corresponding to the global minimum of the 98-atom Lennard-Jones cluster has been found using a variant of the basin-hopping global optimization algorithm. The new structure has an unusual tetrahedral symmetry with an energy of -543.665361, which is 0.022404 lower than the previous putative global minimum. The new LJ_98 structure is of particular interest because its tetrahedral symmetry establishes it as one of only three types of exceptions to the general pattern of icosahedral structural motifs for optimal LJ microclusters. Similar to the other exceptions the global minimum is difficult to find because it is at the bottom of a narrow funnel which only becomes thermodynamically most stable at low temperature.Comment: 3 pages, 2 figures, revte

Squamous cell carcinoma of the nasal cavity:A descriptive analysis of cases from the Head and Neck 5000 study

OBJECTIVES: This paper aims to provide contemporary epidemiological data on squamous cell carcinoma (SCC) of the nasal cavity, which represents a rare type of head and neck cancer.DESIGN, SETTING &amp; PARTICIPANTS: A descriptive analysis of people with nasal cavity SCC treated with curative intent from the Head and Neck 5000 study; a multicentre clinical cohort study of people from the UK with head and neck cancer. People with tumours of the nasopharynx, paranasal sinuses and other sub-sites of the head and neck were excluded.MAIN OUTCOME MEASURES: Demographic data and treatment details are presented for all participants. The main outcomes were overall survival and survival according to categories of characteristics (e.g. smoker vs non-smoker); these were explored using Kaplan-Meier plots.RESULTS: Thirty people with nasal cavity SCC were included in the study, of which most were male (67%) and current or ex-smokers (70%). The majority (70%) presented with early stage (T1/2, N0) tumours. Cervical lymph node metastases at presentation were rare, occurring in only one person. Nine people died during the follow up period (30%). Worse survival outcomes were seen in people with moderate or severe co-morbidities.CONCLUSIONS: This paper provides epidemiological data on nasal cavity SCC in the UK. Patterns of disease and survival outcomes are described, identifying high-risk groups. Further studies should explore whether primary treatment modality alters survival. This article is protected by copyright. All rights reserved.</p

Polytetrahedral Clusters

By studying the structures of clusters bound by a model potential that favours polytetrahedral order, we find a previously unknown series of `magic numbers' (i.e. sizes of special stability) whose polytetrahedral structures are characterized by disclination networks that are analogous to hydrocarbons.Comment: 4 pages, 4 figure

Characterisation of the bacterial and fungal communities associated with different lesion sizes of Dark Spot Syndrome occurring in the Coral Stephanocoenia intersepta

The number and prevalence of coral diseases/syndromes are increasing worldwide. Dark Spot Syndrome (DSS) afflicts numerous coral species and is widespread throughout the Caribbean, yet there are no known causal agents. In this study we aimed to characterise the microbial communities (bacteria and fungi) associated with DSS lesions affecting the coral Stephanocoenia intersepta using nonculture molecular techniques. Bacterial diversity of healthy tissues (H), those in advance of the lesion interface (apparently healthy AH), and three sizes of disease lesions (small, medium, and large) varied significantly (ANOSIM R = 0.052 p,0.001), apart from the medium and large lesions, which were similar in their community profile. Four bacteria fitted into the pattern expected from potential pathogens; namely absent from H, increasing in abundance within AH, and dominant in the lesions themselves. These included ribotypes related to Corynebacterium (KC190237), Acinetobacter (KC190251), Parvularculaceae (KC19027), and Oscillatoria (KC190271). Furthermore, two Vibrio species, a genus including many proposed coral pathogens, dominated the disease lesion and were absent from H and AH tissues, making them candidates as potential pathogens for DSS. In contrast, other members of bacteria from the same genus, such as V. harveyii were present throughout all sample types, supporting previous studies where potential coral pathogens exist in healthy tissues. Fungal diversity varied significantly as well, however the main difference between diseased and healthy tissues was the dominance of one ribotype, closely related to the plant pathogen, Rhytisma acerinum, a known causal agent of tar spot on tree leaves. As the corals’ symbiotic algae have been shown to turn to a darker pigmented state in DSS (giving rise to the syndromes name), the two most likely pathogens are R. acerinum and the bacterium Oscillatoria, which has been identified as the causal agent of the colouration in Black Band Disease, another widespread coral disease

Optical research: a curated visual music collection

Optical Research is a curated collection of visual music by a group of 12 international artists, which has recently been presented as a DVD, a gallery installation, and will be presented at the British Computer Society Electronic Visualisation and the Arts: EVA London 2015

The Effect of iCook 4-H, a Childhood Obesity Prevention Program, on Blood Pressure and Quality of Life in Youth and Adults: A Randomized Control Trial

Objective: Obesity increases the risk of developing hypertension and from population-based samples with estimations that of 2-4% of the U.S. pediatric population has hypertension, which may affect quality of life. This study examined the effects of an obesity prevention program on blood pressure and quality of life in youth and adult participants. Methods: A multi-state research team recruited treatment dyads (youth and their adult meal preparer) to participate in a 12-week randomized control trial and follow-up through 24 months. The treatment group received a cooking and physical activity intervention, followed by booster sessions and mailed newsletters over the remaining two-year period. The control group received no intervention. Resting blood pressure and health related quality of life (HRQOL) surveys were administered at 0,4,12 and 24 months. Results: 228 dyads were recruited (n=77 control and n=151 for treatment). Youth and adult systolic blood pressure (SBP) increased over the 24 months (p=0.003 and p=0.03, respectively) with no differences between groups. From baseline to 24 months both control and treatment youths’ physical and psychological HRQOL increased (p=0.01 and p=0.002, respectively). At 0 and 4 months, youth and adult SBP was positively correlated (r=0.24, p=0.003 and r=0.33, p\u3c0.001, respectively). In the treatment group, there was an inverse association between adult SBP and youth psychological HRQOL at 4 months (r=-0.20, p=0.04), and a similar trend in adult SBP and youth physical HRQOL at 4 months in the treatment group (r=-0.19, p=0.05). Conclusion: A youth-adult dyad obesity prevention program consisting of culinary, mealtime and physical activity education, elicited improvements in HRQOL in youth participants

Why I tense up when you watch me: inferior parietal cortex mediates an audience’s influence on motor performance

The presence of an evaluative audience can alter skilled motor performance through changes in force output. To investigate how this is mediated within the brain, we emulated real-time social monitoring of participants’ performance of a fine grip task during functional magnetic resonance neuroimaging. We observed an increase in force output during social evaluation that was accompanied by focal reductions in activity within bilateral inferior parietal cortex. Moreover, deactivation of the left inferior parietal cortex predicted both inter- and intra-individual differences in socially-induced change in grip force. Social evaluation also enhanced activation within the posterior superior temporal sulcus, which conveys visual information about others’ actions to the inferior parietal cortex. Interestingly, functional connectivity between these two regions was attenuated by social evaluation. Our data suggest that social evaluation can vary force output through the altered engagement of inferior parietal cortex; a region implicated in sensorimotor integration necessary for object manipulation, and a component of the action-observation network which integrates and facilitates performance of observed actions. Social-evaluative situations may induce high-level representational incoherence between one’s own intentioned action and the perceived intention of others which, by uncoupling the dynamics of sensorimotor facilitation, could ultimately perturbe motor output

Facial expressions depicting compassionate and critical emotions: the development and validation of a new emotional face stimulus set

Attachment with altruistic others requires the ability to appropriately process affiliative and kind facial cues. Yet there is no stimulus set available to investigate such processes. Here, we developed a stimulus set depicting compassionate and critical facial expressions, and validated its effectiveness using well-established visual-probe methodology. In Study 1, 62 participants rated photographs of actors displaying compassionate/kind and critical faces on strength of emotion type. This produced a new stimulus set based on N = 31 actors, whose facial expressions were reliably distinguished as compassionate, critical and neutral. In Study 2, 70 participants completed a visual-probe task measuring attentional orientation to critical and compassionate/kind faces. This revealed that participants lower in self-criticism demonstrated enhanced attention to compassionate/kind faces whereas those higher in self-criticism showed no bias. To sum, the new stimulus set produced interpretable findings using visual-probe methodology and is the first to include higher order, complex positive affect displays