995 research outputs found
Using measurements for evaluation of black carbon modeling
The ever increasing use of air quality and climate model assessments to underpin economic, public health, and environmental policy decisions makes effective model evaluation critical. This paper discusses the properties of black carbon and light attenuation and absorption observations that are the key to a reliable evaluation of black carbon model and compares parametric and nonparametric statistical tools for the quantification of the agreement between models and observations. Black carbon concentrations are simulated with TM5/M7 global model from July 2002 to June 2003 at four remote sites (Alert, Jungfraujoch, Mace Head, and Trinidad Head) and two regional background sites (Bondville and Ispra). Equivalent black carbon (EBC) concentrations are calculated using light attenuation measurements from January 2000 to December 2005. Seasonal trends in the measurements are determined by fitting sinusoidal functions and the representativeness of the period simulated by the model is verified based on the scatter of the experimental values relative to the fit curves. When the resolution of the model grid is larger than 1° × 1°, it is recommended to verify that the measurement site is representative of the grid cell. For this purpose, equivalent black carbon measurements at Alert, Bondville and Trinidad Head are compared to light absorption and elemental carbon measurements performed at different sites inside the same model grid cells. Comparison of these equivalent black carbon and elemental carbon measurements indicates that uncertainties in black carbon optical properties can compromise the comparison between model and observations. During model evaluation it is important to examine the extent to which a model is able to simulate the variability in the observations over different integration periods as this will help to identify the most appropriate timescales. The agreement between model and observation is accurately described by the overlap of probability distribution (PD) curves. Simple monthly median comparisons, the Student's t-test, and the Mann-Whitney test are discussed as alternative statistical tools to evaluate the model performance. The agreement measured by the Student's t-test, when applied to the logarithm of EBC concentrations, overestimates the higher PD agreements and underestimates the lower PD agreements; the Mann-Whitney test can be employed to evaluate model performance on a relative scale when the shape of model and experimental distributions are similar
Measurements of the Cerenkov light emitted by a TeO2 crystal
Bolometers have proven to be good instruments to search for rare processes
because of their excellent energy resolution and their extremely low intrinsic
background. In this kind of detectors, the capability of discriminating alpha
particles from electrons represents an important aspect for the background
reduction. One possibility for obtaining such a discrimination is provided by
the detection of the Cerenkov light which, at the low energies of the natural
radioactivity, is only emitted by electrons. In this paper, the results of the
analysis of the light emitted by a TeO2 crystal at room temperature when
transversed by a cosmic ray are reported. Light is promptly emitted after the
particle crossing and a clear evidence of its directionality is also found.
These results represent a strong indication that Cerenkov light is the main, if
not even the only, component of the light signal in a TeO2 crystal. They open
the possibility to make large improvements in the performance of experiments
based on this kind of material
Teaching design in emerging countries A train-the-trainer methodology
Design disciplines have constantly evolved to keep up with the emerging demands of the 21st Century. Design education is thus called to change its methods, tools and approaches. There is an increasing interest in emerging economies in design education, especially in India, where the role of creativity, communication and technology can support social and economic development. This paper aims to present the educational approach developed in the context of the Erasmus+ KA2 project entitled ‘Design and Innovation Capacity Building in India/DESINNO’. The modernisation and internationalisation of Indian universities with innovative and contemporary design courses have been the main goals of a set of research and training activities. In this paper, the state-of-the-art methodologies in design thinking, sustainability, design research, social innovation and ethical issues in design are presented, leading to a bespoke educational approach that provides a platform for Indian design academics to apply modern educational approaches
to their specificities and needs
Aerosol effect on climate extremes in Europe under different future scenarios
This study investigates changes in extreme temperature and precipitation events under different future scenarios of anthropogenic aerosol emissions (i.e., SO2 and black and organic carbon) simulated with an aerosol-climate model (ECHAM5-HAM) with focus on Europe. The simulations include a maximum feasible aerosol reduction (MFR) scenario and a current legislation emission (CLEmod) scenario where Europe implements the MFR scenario, but the rest of the world follows the current legislation scenario and a greenhouse gas scenario. The strongest changes relative to the year 2000 are projected for the MFR scenario, in which the global aerosol reduction greatly enforces the general warming effect due to greenhouse gases and results in significant increases of temperature and precipitation extremes in Europe. Regional warming effects can also be identified from aerosol reductions under the CLEmodscenario. This becomes most obvious in the increase of the hottest summer daytime temperatures in Northern Europe. © 2013 American Geophysical Union. All Rights Reserved
Discovery of a binary AGN in the ultraluminous infrared galaxy NGC 6240 using Chandra
Ultraluminous infrared galaxies (ULIRGs) are outstanding due to their huge
luminosity output in the infrared, which is predominantly powered by super
starbursts and/or hidden active galactic nuclei (AGN). NGC 6240 is one of the
nearest ULIRGs and is considered a key representative of its class.
Here, we report the first high-resolution imaging spectroscopy of NGC 6240 in
X-rays. The observation, performed with the ACIS-S detector aboard the Chandra
X-ray observatory, led to the discovery of two hard nuclei, coincident with the
optical-IR nuclei of NGC 6240. The AGN character of both nuclei is revealed by
the detection of absorbed hard, luminous X-ray emission and two strong neutral
Fe_K_alpha lines. In addition, extended X-ray emission components are present,
changing their rich structure in dependence of energy. The close correlation of
the extended emission with the optical Halpha emission of NGC 6240, in
combination with the softness of its spectrum, clearly indicates its relation
to starburst-driven superwind activity.Comment: ApJ Letters in press, 7 colour figures included; preprint and related
papers on NGC 6240 also available at http://www.xray.mpe.mpg.de/~skomossa
The aerosol-climate model ECHAM5-HAM
The aerosol-climate modelling system ECHAM5-HAM is introduced. It is based on a flexible microphysical approach and, as the number of externally imposed parameters is minimised, allows the application in a wide range of climate regimes. ECHAM5-HAM predicts the evolution of an ensemble of microphysically interacting internally- and externally-mixed aerosol populations as well as their size-distribution and composition. The size-distribution is represented by a superposition of log-normal modes. In the current setup, the major global aerosol compounds sulfate (SU), black carbon (BC), particulate organic matter (POM), sea salt (SS), and mineral dust (DU) are included. The simulated global annual mean aerosol burdens (lifetimes) for the year 2000 are for SU: 0.80 Tg(S) (3.9 days), for BC: 0.11 Tg (5.4 days), for POM: 0.99 Tg (5.4 days), for SS: 10.5 Tg (0.8 days), and for DU: 8.28 Tg (4.6 days). An extensive evaluation with in-situ and remote sensing measurements underscores that the model results are generally in good agreement with observations of the global aerosol system. The simulated global annual mean aerosol optical depth (AOD) is with 0.14 in excellent agreement with an estimate derived from AERONET measurements (0.14) and a composite derived from MODIS-MISR satellite retrievals (0.16). Regionally, the deviations are not negligible. However, the main patterns of AOD attributable to anthropogenic activity are reproduced
Measurements and optimization of the light yield of a TeO crystal
Bolometers have proven to be good instruments to search for rare processes
because of their excellent energy resolution and their extremely low intrinsic
background. In this kind of detectors, the capability of discriminating alpha
particles from electrons represents an important aspect for the background
reduction. One possibility for obtaining such a discrimination is provided by
the detection of the Cherenkov light which, at the low energies of the natural
radioactivity, is only emitted by electrons. This paper describes the method
developed to evaluate the amount of light produced by a crystal of TeO when
hit by a 511 keV photon. The experimental measurements and the results of a
detailed simulation of the crystal and the readout system are shown and
compared. A light yield of about 52 Cherenkov photons per deposited MeV was
measured. The effect of wrapping the crystal with a PTFE layer, with the aim of
maximizing the light collection, is also presented
Pain Distraction During Awake Major Colorectal Surgery: Supporting Patients Beyond the COVID-19 Era. Preliminary Findings
Introduction: During the coronavirus disease 2019 (COVID-19) pandemic, hospitals rapidly ran out of intensive care beds. Because minimally invasive surgery and general anaesthesia are both aerosol-generating procedures, their use has become controversial. We report a case series of awake undelayable colorectal surgeries which, innovatively, took advantage of intraoperative pain distraction. Moreover, we describe our frugal solution to social distancing in psychological support of inpatients.
Methods: Between October 2020 and February 2021, five patients underwent acute-care colorectal surgery under locoregional anaesthesia in our department. A 3D mobile theatre (3DMT) was used during the operation to distract the patients from pain. Vital signs, pain intensity, ergonomic comfort/discomfort, sense of presence and distress were intraoperatively monitored. A postoperative “cuddle delivery” service was instituted: video messages from relatives and close friends were delivered daily to the patient through the 3DMT. Emotional effects were investigated through clinical interviews conducted by a psychologist at our hospital.
Results: Both intraoperative and postoperative pain were always well controlled. Conversion to general anaesthesia and postoperative intensive support/monitoring were never necessary. The “cuddle delivery” initiative helped patients fill the emotional gap created by the strict containment measures implemented inside the hospital, distracting them from emotional anxiety and physical pain.
Conclusions: During the next phase of the COVID-19 pandemic and even after the COVID-19 era, awake laparotomy under locoregional anaesthesia may be a crucial option for delivering acute-care surgery to selected patients when intensive care beds are unavailable and postponing surgery is unacceptable. We also introduce a new modality for the provision of emotional support during postoperative inpatient care as a countermeasure to the restrictions imposed by social distancing measures
New experimental limits on the alpha decays of lead isotopes
For the first time a PbWO4 crystal was grown using ancient Roman lead and it
was run as a cryogenic detector. Thanks to the simultaneous and independent
read-out of heat and scintillation light, the detector was able to discriminate
beta/gamma interactions with respect to alpha particles down to low energies.
New more stringent limits on the alpha decays of the lead isotopes are
presented. In particular a limit of T_{1/2} > 1.4*10^20 y at a 90% C.L. was
evaluated for the alpha decay of 204Pb to 200Hg
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