776 resultados para perception of time
Resumo:
Fluvial islands are emergent landforms which form at the interface between the permanently inundated areas of the river channel and the more stable areas of the floodplain as a result of interactions between physical river processes, wood and riparian vegetation. These highly dynamical systems are ideal to study soil structure development in the short to medium term, a process in which soil biota and plants play a substantial role. We investigated soil structure development on islands along a 40 year chronosequence within a 3 km island-braided reach of the Tagliamento River, Northeastern Italy. We used several parameters to capture different aspects of the soil structure, and measured biotic (e.g., fungal and plant root parameters) and abiotic (e.g. organic carbon) factors expected to determine the structure. We estimated models relating soil structure to its determinants, and, in order to confer statistical robustness to our results, we explicitly took into account spatial autocorrelation, which is present due to the space for time substitution inherent in the study of chronosequences and may have confounded results of previous studies. We found that, despite the eroding forces from the hydrological and geomorphological dynamics to which the system is subject, all soil structure variables significantly, and in some case greatly increased with site age. We interpret this as a macroscopic proxy for the major direct and indirect binding effects exerted by root variables and extraradical hyphae of arbuscular mycorrhizal fungi (AMF). Key soil structure parameters such as percentage of water stable aggregates (WSA) can double from the time the island landform is initiated (mean WSA = 30%) to the full 40 years (mean WSA = 64%) covered by our chronosequence. The study demonstrates the fundamental role of soil biota and plant roots in aggregating soils even in a system in which intense short to medium term physical disturbances are common.
Resumo:
Laughter is a ubiquitous social signal in human interactions yet it remains understudied from a scientific point of view. The need to understand laughter and its role in human interactions has become more pressing as the ability to create conversational agents capable of interacting with humans has come closer to a reality. This paper reports on three aspects of the human perception of laughter when context has been removed and only the body information from the laughter episode remains. We report on ability to categorise the laugh type and the sex of the laugher; the relationship between personality factors with laughter categorisation and perception; and finally the importance of intensity in the perception and categorisation of laughter.
Resumo:
Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.
Resumo:
Irreversibility is one of the most intriguing concepts in physics. While microscopic physical laws are perfectly reversible, macroscopic average behavior has a preferred direction of time. According to the second law of thermodynamics, this arrow of time is associated with a positive mean entropy production. Using a nuclear magnetic resonance setup, we measure the nonequilibrium entropy produced in an isolated spin-1/2 system following fast quenches of an external magnetic field and experimentally demonstrate that it is equal to the entropic distance, expressed by the Kullback-Leibler divergence, between a microscopic process and its time-reverse. Our result addresses the concept of irreversibility from a microscopic quantum standpoint.
Resumo:
Background: Cachexia has been defined as an on-going loss of skeletal muscle mass that cannot be fully reversed by conventional nutritional support. It can be found in up to 80% of patients with advanced cancer and has profound psycho-social consequences for patients and their families. There is a paucity of studies examining the role and experience of healthcare professionals in relation to cachexia and existing studies suggest that professional staff have limited understanding and do not intervene effectively.
Aim: To identify barriers and facilitators to good practice in cachexia care in order to inform future developments in service provision.
Design: An exploratory qualitative study was conducted employing semi-structured interviews with a range of healthcare professionals recruited purposefully from an Australian hospital. Interviews were conducted in private rooms within the hospital.
Setting/participants: A range of healthcare professionals responsible for cancer care were recruited from a large Australian teaching hospital.
Results: Interviews were conducted with 8 healthcare professionals responsible for delivering cancer care. Four themes were identified: formal and informal education, knowledge and understanding, truth telling in cachexia and palliative care, and, a multi-disciplinary approach. Findings show how improved knowledge and understanding across a staff body can lead to improved staff confidence and a willingness to address cancer cachexia and its consequences with patients and their families.
Conclusion: Comparison with previous studies illustrates the importance of improving knowledge and understanding about cachexia and how this can contribute to staff having the skills and experience necessary to address cachexia and provide an improved care experience for patients and carers.
Resumo:
The Asymmetric Power Arch representation for the volatility was introduced by Ding et al.(1993) in order to account for asymmetric responses in the volatility in the analysis of continuous-valued financial time series like, for instance, the log-return series of foreign exchange rates, stock indices or share prices. As reported by Brannas and Quoreshi (2010), asymmetric responses in volatility are also observed in time series of counts such as the number of intra-day transactions in stocks. In this work, an asymmetric power autoregressive conditional Poisson model is introduced for the analysis of time series of counts exhibiting asymmetric overdispersion. Basic probabilistic and statistical properties are summarized and parameter estimation is discussed. A simulation study is presented to illustrate the proposed model. Finally, an empirical application to a set of data concerning the daily number of stock transactions is also presented to attest for its practical applicability in data analysis.
Resumo:
A review of 'Cartographies of Time: a history of the timeline' by Daniel Rosenberg and Anthony Grafton. Princeton, NJ: Princeton Architectural Press, 2010. (272pp. ISBN: 9781568987637). Keywords: timeline, chronographics
Resumo:
Geographical representations of topographical space come in many shapes and are a regular topic of discussion. The depiction of the invisible and maybe even illusory concept of time on the other hand, remains largely unchanged and undisputed. A uniform and arithmetic model of time fits well with the rigid structure of digital data, which might be why it has been widely adopted within HCI. In our proposal, we will present historic and contemporary approaches that offer alternative perspectives on the visual representation of time. Keywords: timeline, chronographics