329 research outputs found
Determination of the optimal priming interval of rumen fluids used as inocula for the in vitro digestibility trials through radial enzyme diffusion method
Context: Determination of the neutral detergent fibre digestibility is one of the important parameters to consider when formulating diets. However, the in vitro determination shows low repeatability because of the source of rumen-fluid inoculum. Priming of the rumen fluid inocula, obtained through an oesophageal probe, has been proposed to overcome this issue. Aim: The objective of the study was to investigate the evolution of the microbial enzymatic activities of different rumen fluids during a priming procedure, to establish the fermentation interval that minimises the differences among rumen-fluid degradative potentials. Methods: Three farms for each type of diet were involved in the study. Rumen fluids were obtained from dry and lactating cows fed the following four diet types: 100% hay or a diet with 80: 20 forage: Concentrate ratio (F: C) as dry-cow diets, and ad libitum hay and concentrate, or a total mixed ration (both at 60: 40 F: C) as lactating-cow diets. On each farm, rumen fluid was collected from three Holstein cows by using an oesophageal probe, and mixed. Two aliquots of each rumen fluid mix were added to the medium containing the same priming substrate in an in vitro batch-fermentation system. During the incubation, the fermentation fluids were sampled in duplicate at 0-, 1-, 2-, 4-, 8-, 24- A nd 48-h intervals. Enzymatic activities of amylase, cellulase and xylanase were determined by radial enzyme diffusion method. Key results: Initial enzymatic activities were quite variable and increased with an increasing incubation time. By 24 h, amylase showed similar values among high-concentrate diet fermentation fluids, and a lower data dispersion in comparison to the other intervals cellulase was characterised by similar values in all the fermentation fluids derived from diets including concentrates, and xylanase showed similar activity in the fermentation fluids derived from high-concentrate diets. Development of the enzymatic activity of the fermentation fluids derived from the 100% hay diet differed from the others. Conclusions: A 24-h priming procedure was needed to stabilise and equalise the enzymatic activity of the rumen fluid from cows fed high-concentrate diets. This was not observed in rumen fluid from cows fed hay-based diets. Implications: The 24-h-primed rumen fluid can be used to increase the repeatability of neutral detergent fibre digestibility determination
Post- and peritraumatic stress in disaster survivors: An explorative study about the influence of individual and event characteristics across different types of disasters
Background:
Examination of existing research on posttraumatic adjustment after disasters suggests that survivors’ posttraumatic stress levels might be better understood by investigating the influence of the characteristics of the event experienced on how people thought and felt, during the event as well as afterwards.
Objective:
To compare survivors’ perceived post- and peritraumatic emotional and cognitive reactions across different types of disasters. Additionally, to investigate individual and event characteristics.
Design:
In a European multi-centre study, 102 survivors of different disasters terror attack, flood, fire and collapse of a building were interviewed about their responses during the event. Survivors’ perceived posttraumatic stress levels were assessed with the Impact of Event Scale-Revised (IES-R). Peritraumatic emotional stress and risk perception were rated retrospectively. Influences of individual characteristics, such as socio-demographic data, and event characteristics, such as time and exposure factors, on post- and peritraumatic outcomes were analyzed.
Results:
Levels of reported post- and peritraumatic outcomes differed significantly between types of disasters. Type of disaster was a significant predictor of all three outcome variables but the factors gender, education, time since event, injuries and fatalities were only significant for certain outcomes.
Conclusion:
Results support the hypothesis that there are differences in perceived post- and peritraumatic emotional and cognitive reactions after experiencing different types of disasters. However, it should be noted that these findings were not only explained by the type of disaster itself but also by individual and event characteristics. As the study followed an explorative approach, further research paths are discussed to better understand the relationships between variables
Emergent organization and responsive technologies in crisis: Creating connections or enabling divides
I articulate and employ a situational boundary-making approach to study the emergence of organization and technology at a shelter during Hurricane Katrina. My analysis of qualitative data shows how emergent organization occurred at the shelter as situational entanglements consisting of three main elements: a salient moment in time, key actors, and boundary-making practices. Key actors' responses to salient moments in time enacted both distinction and dependency between organizational and technological actors, resulting in a divided organization. This analysis extends emergent approaches by showing how organization and technology are situationally organized and emerges through the (in)determinacy of meaning. Implications are also discussed for disaster managers to assess the success and failure of technology during a response. © The Author(s) 2012
Brain Plasticity in Charcot-Marie-Tooth Type 1A Patients? A Combined Structural and Diffusion MRI Study
Central nervous system involvement has been described in peripheral neuropathies, including different forms of Charcot-Marie-Tooth (CMT) disease. The aim of our study was to systematically investigate possible brain structural modifications in CMT1A patients, using volumetric MRI, and diffusion tensor imaging (DTI). In this prospective cross-sectional study, from May 2017 to May 2019, we acquired 3T MRI brain scans of genetically confirmed CMT1A patients and age- and sex-comparable healthy controls. Patients also underwent clinical and electrophysiological examinations assessing motor and sensory domains. Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analyses were performed using a non-parametric approach based on permutations, including age and sex (and total intracranial volume for VBM) as nuisance covariates. When between-group differences emerged at VBM or TBSS analyses, the first eigenvariate was extracted from the cluster and its age- and sex-adjusted standardized residuals tested for correlation with clinical and electrophysiological variables. Twenty CMT1A patients (34.5 ± 11.1 years; M/F:11/9) were enrolled, along with 20 healthy controls (30.1 ± 10.2 years; M/F:11/9). The VBM analysis revealed clusters of significantly increased GM volume in CMT1A patients compared to healthy controls, encompassing the bilateral cerebellar lobules III-VI and the left hippocampus (all ps = 0.04), with no differences in terms of DTI metrics at the TBSS analysis. A negative correlation (r = −0.502, p = 0.03) emerged between ulnar compound motor action potential and the z-scores corresponding to the right cerebellar cluster of augmented GM volume. Our data show evidence of structural reorganization in the brain of CMT1A patients, possibly reflecting neural plasticity mechanisms in response to peripheral nerve pathology and modulating the effect of axonal degeneration on functional impairment
The structural connectome constrains fast brain dynamics
Brain activity during rest displays complex, rapidly evolving patterns in space and time. Structural connections comprising the human connectome are hypothesized to impose constraints on the dynamics of this activity. Here, we use magnetoencephalography (MEG) to quantify the extent to which fast neural dynamics in the human brain are constrained by structural connections inferred from diffusion MRI tractography. We characterize the spatio-temporal unfolding of whole-brain activity at the millisecond scale from source-reconstructed MEG data, estimating the probability that any two brain regions will significantly deviate from baseline activity in consecutive time epochs. We find that the structural connectome relates to, and likely affects, the rapid spreading of neuronal avalanches, evidenced by a significant association between these transition probabilities and structural connectivity strengths (r = 0.37, p<0.0001). This finding opens new avenues to study the relationship between brain structure and neural dynamics
Simulating Dynamical Features of Escape Panic
One of the most disastrous forms of collective human behaviour is the kind of
crowd stampede induced by panic, often leading to fatalities as people are
crushed or trampled. Sometimes this behaviour is triggered in life-threatening
situations such as fires in crowded buildings; at other times, stampedes can
arise from the rush for seats or seemingly without causes. Tragic examples
within recent months include the panics in Harare, Zimbabwe, and at the
Roskilde rock concert in Denmark. Although engineers are finding ways to
alleviate the scale of such disasters, their frequency seems to be increasing
with the number and size of mass events. Yet, systematic studies of panic
behaviour, and quantitative theories capable of predicting such crowd dynamics,
are rare. Here we show that simulations based on a model of pedestrian
behaviour can provide valuable insights into the mechanisms of and
preconditions for panic and jamming by incoordination. Our results suggest
practical ways of minimising the harmful consequences of such events and the
existence of an optimal escape strategy, corresponding to a suitable mixture of
individualistic and collective behaviour.Comment: For related information see http://angel.elte.hu/~panic,
http://www.helbing.org, http://angel.elte.hu/~fij, and
http://angel.elte.hu/~vicse
La incuestionabilidad del riesgo
Con anterioridad a la década de 1980, la literatura especializada en análisis y gestión del riesgo estaba dominada por la llamada visión tecnocrática o dominante. Esta visión establecía que los desastres naturales eran sucesos físicos extremos, producidos por una naturaleza caprichosa, externos a lo social y que requerían soluciones tecnológicas y de gestión por parte de expertos. Este artículo se centra en desarrollar una nueva explicación para entender la persistencia hegemónica de la visión tecnocrática basada en el concepto de incuestionabilidad del riesgo. Esta propuesta conceptual hace referencia a la incapacidad y desidia de los expertos, científicos y tomadores de decisiones en general (claimmakers) de identificar y actuar sobre las causas profundas de la producción del riesgo ya que ello conllevaría a cuestionar los imperativos normativos, las necesidades de las elites y los estilos de vida del actual sistema socioeconómico globalizado.Before de 1980s, the natural hazard analysis and management specialized literature was dominated by the so called "dominant" or "technocratic" view. Such perspective had established that natural disasters are extreme physical events caused by a whimsical nature and that these events are external to society. These events required technological and management solutions developed by experts. The current article aims at addressing a new explanatory component in the hegemonic persistence of the technocratic view. Such assumption was based on the "unquestionability of the risk" concept. It is stated that the "unquestionability of the risk" is the overall incapacity and neglect of experts, scientists and decision makers to identify and act over the deep causes of risk production, since it would make them question the normative imperatives and the demands from the elite as well as the life style in nowadays globalized socio-economic system
Fear of the unknown: a pre-departure qualitative study of Turkish international students
This paper presents findings from eleven in-depth interviews with Turkish undergraduate students, who were, by the time of data collection, about to spend a semester at a European university under the Erasmus exchange scheme. The students all agreed to be interviewed about their feelings about studying in a foreign culture, and were found to be anxious prior to departure about the quality of accommodation in the new destination, their language ability and the opportunity to form friendships. Fears were expressed about possible misconceptions over Turkey as a Muslim and a developing country. Suggestions are made for HEI interventions to allay student travellers’ concerns
Imagining worse than reality: comparing beliefs and intentions between disaster evacuees and survey respondents
We often credit disasters, and their coverage in the media, with changes in the public perception of risk associated with low-probability, high-consequence events (LPHCs). With a change in perceptions, we also expect changes in beliefs, preferences, and behaviors. Do beliefs and behaviors change in different ways for people who live through these LPHC critical events, as opposed to people who observe them? This study compares hypothetical hurricanes with actual hurricane effects in a survey quasi-experiment. Findings indicate that hypothetical disasters induce stronger reactions than those experienced in the natural world, as Hurricane Katrina bystanders imagine themselves incurring much higher damages, and being much less likely to return to live in their hurricane-damaged homes, than actual Hurricane Katrina evacuees. Ultimately, respondents considering a hypothetical low-probability, high-consequence event exhibit exaggerated beliefs and opposite decisions of those who actually lived through one of these events. Results underline the importance of examining the differences between public perceptions and experiential reality
Emergency management in health: key issues and challenges in the UK
Background
Emergency planning in the UK has grown considerably in recent years, galvanised by the threat of terrorism. However, deficiencies in NHS emergency planning were identified and the evidence-base that underpins it is questionable. Inconsistencies in terminologies and concepts also exist. Different models of emergency management exist internationally but the optimal system is unknown. This study examines the evidence-base and evidence requirements for emergency planning in the UK health context.
Methods
The study involved semi-structured interviews with key stakeholders and opinion leaders. Purposive sampling was used to obtain a breadth of views from various agencies involved in emergency planning and response. Interviews were then analysed using a grounded approach using standard framework analysis techniques.
Results
We conducted 17 key informant interviews. Interviewees identified greater gaps in operational than technical aspects of emergency planning. Social and behavioural knowledge gaps were highlighted with regards to how individuals and organisations deal with risk and behave in emergencies. Evidence-based approaches to public engagement and for developing community resilience to disasters are lacking. Other gaps included how knowledge was developed and used. Conflicting views with regards to the optimal configuration and operation of the emergency management system were voiced.
Conclusions
Four thematic categories for future research emerged:
(i) Knowledge-base for emergency management: Further exploration is needed of how knowledge is acquired, valued, disseminated, adopted and retained.
(ii) Social and behavioural issues: Greater understanding of how individuals approach risk and behave in emergencies is required.
(iii) Organisational issues in emergencies: Several conflicting organisational issues were identified; value of planning versus plans, flexible versus standardized procedures, top-down versus bottom-up engagement, generic versus specific planning, and reactive versus proactive approaches to emergencies.
(iv) Emergency management system: More study is required of system-wide issues relating to system configuration and operation, public engagement, and how emergency planning is assessed
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