228 research outputs found
Impact of data assimilation of glider observations in the Ionian Sea (Eastern Mediterranean)
Glider observations of temperature, salinity and vertically averaged velocity in the Ionian Sea
(Eastern Mediterranean Sea), made in the period October 2004 - December 2004, were assimilated
into an operational forecasting model together with other in-situ and satellite observations. The
study area has a high spatial and temporal variability of near-surface dynamics, characterized by
the entrance of the Atlantic Ionian Stream (AIS) into the Northern Ionian Sea. The impact of glider
observations on the estimation of the circulation is studied, and it is found that their assimilation
locally improves the prediction of temperature, salinity, velocity and surface elevation fields.
However, only the assimilation of temperature and salinity together with the vertically averaged
velocity improves the forecast of all observed parameters. It is also found that glider observations
rapidly impact the analyses even remotely, and the remote impacts on the analyses remain several
months after the presence of the glider. The study emphasizes the importance of assimilating as
much as possible all available information from gliders, especially in dynamically complex areas
Ionian Sea circulation as clarified by assimilation of glider observations
Glider observations of temperature and salinity in the Ionian Sea (Eastern Mediterranean
Sea), made in the period October 2004-December 2004, were assimilated into an operational
forecasting model together with other in-situ and satellite observations. The impact of glider
data on the estimation of the circulation is studied and it is found that the assimilation of
glider data significantly improve the vertical structure of temperature and salinity fields and
remove biases. The accurate representation of the dynamical structures due to the assimilation
of glider data allowed a detailed analysis of the dynamics of the Atlantic Ionian Stream (AIS).
During autumn and in the Sicily Strait, the AIS is strengthened by the positive but weak wind
stress curl near the southern Sicilian coast and by the temperature gradient between the warm
surface mixed layer and the cold upwelled waters near Sicily. In winter the change of position
of the wind stress curl zero line and the cooling of the surface mixed layer forces the AIS to
shift southward in the Ionian Sea. The AIS is shown for the first time to pinch off an eddy in
the Ionian Sea
The present and future system for measuring the Atlantic meridional overturning circulation and heat transport
of the global combined atmosphere-ocean heat flux and
so is important for the mean climate of the Atlantic
sector of the Northern Hemisphere. This meridional heat
flux is accomplished by both the Atlantic Meridional
Overturning Circulation (AMOC) and by basin-wide
horizontal gyre circulations. In the North Atlantic
subtropical latitudes the AMOC dominates the meridional heat flux, while in subpolar latitudes and in the subtropical South Atlantic the gyre circulations are
also important. Climate models suggest the AMOC will
slow over the coming decades as the earth warms, causing widespread cooling in the Northern hemisphere and additional sea-level rise. Monitoring systems for selected components of the AMOC have been in place in some areas for decades, nevertheless the present observational network provides only a partial view of the AMOC, and does not unambiguously resolve the full variability of the circulation. Additional observations, building on existing measurements, are required to more completely quantify the Atlantic meridional heat transport. A basin-wide monitoring
array along 26.5°N has been continuously measuring the strength and vertical structure of the AMOC and meridional heat transport since March 31, 2004. The array has demonstrated its ability to observe the AMOC variability at that latitude and also a variety of surprising variability that will require substantially longer time series to understand fully. Here we propose monitoring the Atlantic meridional heat transport throughout the Atlantic at selected critical latitudes that have already been identified as regions of interest for the study of deep water formation and the strength of the subpolar gyre, transport variability of the Deep Western Boundary Current (DWBC) as well as the upper limb of the AMOC, and inter-ocean and intrabasin exchanges with the ultimate goal of determining regional and global controls for the AMOC in the North and South Atlantic Oceans. These new arrays will
continuously measure the full depth, basin-wide or choke-point circulation and heat transport at a number
of latitudes, to establish the dynamics and variability at
each latitude and then their meridional connectivity.
Modeling studies indicate that adaptations of the 26.5°N
type of array may provide successful AMOC monitoring at other latitudes. However, further analysis and the development of new technologies will be needed to optimize cost effective systems for providing long term monitoring and data recovery at climate time scales. These arrays will provide benchmark observations of the AMOC that are fundamental for assimilation, initialization, and the verification of coupled hindcast/forecast climate models
Single-shot full strain tensor determination with microbeam X-ray Laue diffraction and a two-dimensional energy-dispersive detector
The antibacterial & antibiofilm activity of Punica granatum peel aqueous extract against some oral pathogen
This study was designed to evaluate the antibacterial & antibiofilm activity of Punica granatum peel aqueous extract against oral pathogens from patients suffering from gingivitis and dental carrier. These isolates were 58.8% gram positive (Lactobacillus spp. ,Streptococcus spp. and Staphylococcus aurus) and 41.2% gram negative (Klebseilla pneumonia and pseudomonas aeruginosa). The susceptibility of these different bacterial species toward the aqueous extract of this plant was applied by using well diffusion agar method. The results were compared with each other and with selected antibiotic ciprofloxacin as positive control. Results showed that aqueous extract of Punica granatum had antibacterial activity against all isolates, on which the diameter of inhibition zone at concentration 200 mg/ml of this extract was 24mm for Lactobacillus spp and 23 mm for Staph aureus and P.aeruginosa, while the Streptococcus spp. was only 18 mm
CODE-2 : moored array and large-scale data report
The Coastal Ocean Dynamics Experiment
(CODE) was undertaken to identify and study
the important dynamical processes which
govern the wind-driven motion of coastal
water over the continental shelf. The
initial effort in this multi-year, multi-institutional
research program was to obtain
high-quality data sets of all the
relevant physical variables needed to construct
accurate kinematic and dynamic descriptions
of the response of shelf water
to strong wind forcing in the 2 to 10 day
band. A series of two small-scale, densely-
instrumented field experiments of approximately
four months duration (called CODE-1
and CODE-2) were designed to explore and
to determine the kinematics and momentum
and heat balances of the local wind-driven
flow over a region of the northern California
shelf which is characterized by both
relatively simple bottom topography and
large wind stress events in both winter
and summer. A more lightly instrumented,
long -term, large-scale component was
designed to help separate the local wind-driven
response in the region of the small-scale
experiments from motions generated
either offshore by the California Current
system or in some distant region along the
coast, and also to help determine the seasonal
cycles of the atmospheric forcing,
water structure, and coastal currents over
the northern California shelf.
The first small-scale experiment
(CODE-1) was conducted between April and
August, 1981 as a pilot study in "which
primary emphasis was placed on characterizing
the wind-driven "signal" and the
"noise" from which this signal must be
extracted. In particular, CODE-1 was
designed to identify the key features of
the circulation and its variability over
the northern California shelf and to
determine the important time and length
scales of the wind-driven response. The
second small-scale experiment (CODE-2) was
conducted between April and August, 1982
and was designed to sample more carefully
the mesoscale horizonta1 variability
observed in CODE-1. This report presents a
basic description of the moored array data
and some other Eulerian data collected
during CODE-2. A brief description of the
CODE-2 field program is presented first,
followed by a description of the common
data analysis procedures used to produce
the various data sets presented here. Then
basic descriptions of the following data
sets are presented: (a) the coastal and
moored meteorological measurements, (b)
the moored current measurements, (c) array
plots of the surface wind stress and near-surface
current measurements, (d) the
moored temperature and conductivity observations,
(e) the bottom pressure measurements,
and (f) the wind and adjusted
coastal sea level observations obtained as
part of the CODE-2 large-scale component.This work has
been supported by the National Science
Foundation
Is motor activity during cognitive assessment an indicator for feigned attention-deficit/hyperactivity disorder (ADHD) in adults?
Objectives: Several approaches, ranging from self-ratings of symptoms and impairments to objective neuropsychological testing, have been utilized during clinical evaluation in order to assess symptom and performance validity of individuals with attention-deficit/hyperactivity disorder (ADHD) in adulthood. Motor activity has not been considered yet in this context, which is surprising given that hyperactivity is a prominent characteristic of ADHD. Hence, the goal of the present study was to explore the incremental value of motor activity when assessing the credibility of individuals with adult ADHD at clinical evaluation.Method: Forty-six patients diagnosed with ADHD took part in the study. A simulation design was performed, in which 152 healthy individuals were allocated to either a control condition (n=36) or one of three simulation conditions (n=116), the latter requesting participants to feign ADHD. All participants completed a self-rating scale of cognitive functioning and performed a computerized test for vigilance. Body movements were recorded during vigilance testing via a motion tracker attached to the back of the participant's chair.Results: Patients with ADHD reported significantly more pronounced cognitive complaints and performed significantly poorer on the vigilance test than control participants. Simulators of ADHD, as compared to genuine patients, showed excessively low performance on the vigilance test. However, neither self-ratings of cognitive functioning nor measures of motor activity were suitable to distinguish genuine from feigned ADHD. A hierarchical logistic regression model showed that motor activity had no incremental value in detecting feigned ADHD when vigilance test performance has already been considered.Conclusions: Standard neuropsychological tests of vigilance may be useful to measure both performance and credibility of individuals with adult ADHD at clinical evaluation. In contrast, self-reports of symptoms and impairments, as well as measures of body movements, may not support the assessment of credibility in this context
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