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Schneefernerhaus as a mountain research station for clouds and turbulence
Cloud measurements are usually carried out with airborne campaigns, which are expensive and are limited by temporal duration and weather conditions. Ground-based measurements at high-altitude research stations therefore play a complementary role in cloud study. Using the meteorological data (wind speed, direction, temperature, humidity, visibility, etc.) collected by the German Weather Service (DWD) from 2000 to 2012 and turbulence measurements recorded by multiple ultrasonic sensors (sampled at 10 Hz) in 2010, we show that the Umweltforschungsstation Schneefernerhaus (UFS) located just below the peak of Zugspitze in the German Alps, at a height of 2650 m, is a well-suited station for cloud–turbulence research. The wind at UFS is dominantly in the east–west direction and nearly horizontal. During the summertime (July and August) the UFS is immersed in warm clouds about 25 % of the time. The clouds are either from convection originating in the valley in the east, or associated with synoptic-scale weather systems typically advected from the west. Air turbulence, as measured from the second- and third-order velocity structure functions that exhibit well-developed inertial ranges, possesses Taylor microscale Reynolds numbers up to 104, with the most probable value at ~ 3000. In spite of the complex topography, the turbulence appears to be nearly as isotropic as many laboratory flows when evaluated on the "Lumley triangle"
Mars and frame-dragging: study for a dedicated mission
In this paper we preliminarily explore the possibility of designing a
dedicated satellite-based mission to measure the general relativistic
gravitomagnetic Lense-Thirring effect in the gravitational field of Mars. The
focus is on the systematic error induced by the multipolar expansion of the
areopotential and on possible strategies to reduce it. It turns out that the
major sources of bias are the Mars'equatorial radius R and the even zonal
harmonics J_L, L = 2,4,6... of the areopotential. An optimal solution, in
principle, consists of using two probes at high-altitudes (a\approx 9500-9600
km) and different inclinations, and suitably combining their nodes in order to
entirely cancel out the bias due to \delta R. The remaining uncancelled
mismodelled terms due to \delta J_L, L = 2,4,6,... would induce a bias \lesssim
1%, according to the present-day MGS95J gravity model, over a wide range of
admissible values of the inclinations. The Lense-Thirring out-of-plane shifts
of the two probes would amount to about 10 cm yr^-1.Comment: LaTex2e, 16 pages, 5 figures, no tables. To appear in General
Relativity and Gravitatio
Occurrence and exposure of 3-monochloropropanediol diesters in edible oils and oil-based foodstuffs from the Spanish market
During the industrial refining process of edible oils and the manufacture of oil-based foodstuff, contaminants such as 3-monochloropropanediol (3-MCPD) fatty acid diesters can be produced. One hundred samples of different edible oils and related fatty food purchased from local Spanish markets were analyzed to evaluate the occurrence of these contaminants. Data of seven 3-MCPD diesters together with corresponding total 3-MCPD equivalents are presented. The procedure is based on a modified QuEChERS protocol followed by LC-MS/MS analysis. Extra virgin olive oil (EVOO) and unrefined oils did not contain detectable levels of the target analytes. The highest levels of 3-MCPD diesters were found in palm oils, for 1,2-Dilinoleoyl-3-chloropropanediol (LILI) and 1–2-Bispalmitoyl-3-chloropropanediol (PAPA) with concentrations close to 10 mg kg−1 and in the lipid fraction of margarines (8.09, 3.77 and 3.72 mg kg−1 for LILI, PAPA and 1-Oleoyl-2-linoleoyl-3-chloropropanediol (OLLI), respectively).Spanish Ministry of Science and Innovation (Project AGL-2014-53647-R) and FEDER fund
Geometrical statistics of the vorticity vector and the strain rate tensor in rotating turbulence
We report results on the geometrical statistics of the vorticity vector
obtained from experiments in electromagnetically forced rotating turbulence. A
range of rotation rates is considered, from non-rotating to rapidly
rotating turbulence with a maximum background rotation rate of rad/s
(with Rossby number much smaller than unity). Typically, in our experiments
. The measurement volume is located in the
centre of the fluid container above the bottom boundary layer, where the
turbulent flow can be considered locally statistically isotropic and
horizontally homogeneous for the non-rotating case, see van Bokhoven et al.,
Phys. Fluids 21, 096601 (2009). Based on the full set of velocity derivatives,
measured in a Lagrangian way by 3D Particle Tracking Velocimetry, we have been
able to quantify statistically the effect of system rotation on several flow
properties. The experimental results show how the turbulence evolves from
almost isotropic 3D turbulence ( rad/s) to quasi-2D
turbulence ( rad/s) and how this is reflected by several
statistical quantities. In particular, we have studied the orientation of the
vorticity vector with respect to the three eigenvectors of the local strain
rate tensor and with respect to the vortex stretching vector. Additionally, we
have quantified the role of system rotation on the self-amplification terms of
the enstrophy and strain rate equations and the direct contribution of the
background rotation on these evolution equations. The main effect is the strong
reduction of extreme events and related (strong) reduction of the skewness of
PDFs of several quantities such as, for example, the intermediate eigenvalue of
the strain rate tensor and the enstrophy self-amplification term.Comment: 17 pages, 6 figures, 3 table
Will the recently approved LARES mission be able to measure the Lense-Thirring effect at 1%?
After the approval by the Italian Space Agency of the LARES satellite, which
should be launched at the end of 2009 with a VEGA rocket and whose claimed goal
is a about 1% measurement of the general relativistic gravitomagnetic
Lense-Thirring effect in the gravitational field of the spinning Earth, it is
of the utmost importance to reliably assess the total realistic accuracy that
can be reached by such a mission. The observable is a linear combination of the
nodes of the existing LAGEOS and LAGEOS II satellites and of LARES able to
cancel out the impact of the first two even zonal harmonic coefficients of the
multipolar expansion of the classical part of the terrestrial gravitational
potential representing a major source of systematic error. While LAGEOS and
LAGEOS II fly at altitudes of about 6000 km, LARES will be placed at an
altitude of 1450 km. Thus, it will be sensitive to much more even zonals than
LAGEOS and LAGEOS II. Their corrupting impact \delta\mu has been evaluated by
using the standard Kaula's approach up to degree L=70 along with the sigmas of
the covariance matrices of eight different global gravity solutions
(EIGEN-GRACE02S, EIGEN-CG03C, GGM02S, GGM03S, JEM01-RL03B, ITG-Grace02s,
ITG-Grace03, EGM2008) obtained by five institutions (GFZ, CSR, JPL, IGG, NGA)
with different techniques from long data sets of the dedicated GRACE mission.
It turns out \delta\mu about 100-1000% of the Lense-Thirring effect. An
improvement of 2-3 orders of magnitude in the determination of the high degree
even zonals would be required to constrain the bias to about 1-10%.Comment: Latex, 15 pages, 1 table, no figures. Final version matching the
published one in General Relativity and Gravitation (GRG
Crystal structure of solid Oxygen at high pressure and low temperature
Results of X-ray diffraction experiments on solid oxygen at low temperature
and at pressures up to 10 GPa are presented.A careful sample preparation and
annealing around 240 K allowed to obtain very good diffraction patterns in the
orthorhombic delta-phase. This phase is stable at low temperature, in contrast
to some recent data [Y. Akahama et al., Phys. Rev. B64, 054105 (2001)], and
transforms with decreasing pressure into a monoclinic phase, which is
identified as the low pressure alpha-phase. The discontinuous change of the
lattice parameters, and the observed metastability of the alpha-phase
increasing pressure suggest that the transition is of the first order.Comment: 4 pages with three figure
Nature of the spin-glass phase at experimental length scales
We present a massive equilibrium simulation of the three-dimensional Ising
spin glass at low temperatures. The Janus special-purpose computer has allowed
us to equilibrate, using parallel tempering, L=32 lattices down to T=0.64 Tc.
We demonstrate the relevance of equilibrium finite-size simulations to
understand experimental non-equilibrium spin glasses in the thermodynamical
limit by establishing a time-length dictionary. We conclude that
non-equilibrium experiments performed on a time scale of one hour can be
matched with equilibrium results on L=110 lattices. A detailed investigation of
the probability distribution functions of the spin and link overlap, as well as
of their correlation functions, shows that Replica Symmetry Breaking is the
appropriate theoretical framework for the physically relevant length scales.
Besides, we improve over existing methodologies to ensure equilibration in
parallel tempering simulations.Comment: 48 pages, 19 postscript figures, 9 tables. Version accepted for
publication in the Journal of Statistical Mechanic
Incidents during out-of-hospital patient transportation
Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsOut-of-hospital patient transportation (retrieval) of critically ill patients occurs within highly complex environments. Adverse events are not uncommon. Incident monitoring provides a means to better understand such events. The aim of this study was to characterize incidents occurring during retrieval to provide a basis for developing corrective strategies. Four organizations contributed 125 reports, documenting 272 incidents; 91% of forms documented incidents as preventable. Incidents related to equipment (37%), patient care (26%), transport operations (11%), interpersonal communication (9%), planning or preparation (9%), retrieval staff (7%) and tasking (2%). Incidents occurred during patient transport to the receiving facility (26%), at patient origin (26%), during patient loading (20%), at the retrieval service base (18%) and receiving facility (9%). Contributing factors were system-based for 54% and human-based for 42%. Haste (7.5%), equipment malfunctioning (7.2%) or missing (5.5%), failure to check (5.8%) and pressure to proceed (5.2%) were the most frequent contributing factors. Harm was documented in 59% of incidents with one death. Minimizing factors were good crew skills/teamwork (42%), checking equipment (17%) and patient (8%), patient monitors (15%), good luck (14%) and good interpersonal communication (4%). Incident monitoring provides sufficient insight into retrieval incidents to be a useful quality improvement tool for retrieval services. Information gathered suggested improvements in retrieval equipment design and use of alternative power sources, the use of pro formae for equipment checking, patient assessment, preparation for transportation and information transfer. Lessons from incidents in other areas applicable to retrieval should be linked for analysis with retrieval incidents.A. Flabouris, W. B. Runciman, B. Levingshttp://www.aaic.net.au/Article.asp?D=200530
Janus II: a new generation application-driven computer for spin-system simulations
This paper describes the architecture, the development and the implementation
of Janus II, a new generation application-driven number cruncher optimized for
Monte Carlo simulations of spin systems (mainly spin glasses). This domain of
computational physics is a recognized grand challenge of high-performance
computing: the resources necessary to study in detail theoretical models that
can make contact with experimental data are by far beyond those available using
commodity computer systems. On the other hand, several specific features of the
associated algorithms suggest that unconventional computer architectures, which
can be implemented with available electronics technologies, may lead to order
of magnitude increases in performance, reducing to acceptable values on human
scales the time needed to carry out simulation campaigns that would take
centuries on commercially available machines. Janus II is one such machine,
recently developed and commissioned, that builds upon and improves on the
successful JANUS machine, which has been used for physics since 2008 and is
still in operation today. This paper describes in detail the motivations behind
the project, the computational requirements, the architecture and the
implementation of this new machine and compares its expected performances with
those of currently available commercial systems.Comment: 28 pages, 6 figure
Still a long way to go to achieve multidisciplinarity for the benefit of patients: commentary on the ESMO position paper (Annals Oncology Jan;25(1): 9-15, 2014)
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