242 research outputs found
Age Related Decrements in Steering Control: The Effects of Landmark and Optical Flow Information
This study examined age related decrements in the use of optical flow and landmark information for the control of steering. Older and younger drivers viewed computer generated displays simulating vehicle motion through a random dot ground plane scene. The horizontal position of the driver was perturbed according a sum of sines function and the driver had to keep steering straight (resembling the task of steering a car on a gusty day). On half the trials, landmark information was presented by color coding one of the dots on the ground plane. Overall, older drivers showed greater steering error magnitude (RMS error) than younger drivers. Unlike the younger drivers, the older drivers showed no reduction in steering errors when landmark information was present. These results suggest that older drivers are more reliant on optical flow information for controlling a vehicle and have a reduced ability to use alternative sources of information, such as landmarks, for steering control
Interpreting the seasonal cycles of atmospheric oxygen and carbon dioxide concentrations at American Samoa Observatory
We present seven years of atmospheric O2/N2 ratio and CO2 concentration data measured from flask samples collected at American Samoa. These data are unusual, exhibiting higher short-term variability, and seasonal cycles not in phase with other sampling stations. The unique nature of atmospheric data from Samoa has been noted previously from measurements of CO2, methyl chloroform, and ozone. With our O2 data, we observe greater magnitude in the short-term variability, but, in contrast, no clear seasonal pattern to this variability. This we attribute to significant regional sources and sinks existing for O2 in both hemispheres, and a dependence on both the latitudinal and altitudinal origins of air masses. We also hypothesize that some samples exhibit a component of "older" air, demonstrating recirculation of air within the tropics. Our findings could be used to help constrain atmospheric transport models which are not well characterized in tropical regions
On the question of whether to model or measure the levels of RF energy from mobile phones into the head
On the question of whether to model or measure the levels of RF energy from mobile phones into the hea
A study of head worn jewellery, mobile phone RF energy and the effect of differing issue types on rates of absorption
This paper investigates the effects of metallic jewellery
on the SAR in progressively more complex models of
the human head, using the FDTD method. A halfwavelength
dipole excitation at 1800MHz is positioned
in front of the head to represent a cellular enabled
personal communication device. FDTD results show
good agreement with DASY4 measurements. Metallic
jewellery has been found to increase SAR in the head
and the levels of SAR depends on the shape and the
electrical properties of the tissues in the head. A
metallic pin was found to increase the SAR averaged
over 1g by 16.0 times in a homogeneous cubic head,
whereas, the same pin increased the 1g SAR in an
anatomically realistic head by a factor of only 2.5. The
results shown in this paper are for a metallic pin that
may represent a facial piercing, a section of metallic
spectacles or a microphone for a hands free kit
Professor Jim James ... a great researcher and motivator in the field of antennas
This paper is dedicated to Professor Jim James. It is a
celebration of his life, career and world renowned research
contribution to the engineering community. Jim was eminent
for his pioneering research contributions to the fundamental
understanding of radiation mechanisms in printed patch and
small antennas including seminal achievements, both
theoretical and in terms of demonstrated practical
applications, in communications, radar and medical
electronics. The paper includes a brief summary of his
research. Details will also be included on some of his latest
work involving low SAR material coated mobile handset
antennas
Broad Balmer Wings in BA Hyper/Supergiants Distorted by Diffuse Interstellar Bands: Five Examples in the 30 Doradus Region from the VLT-FLAMES Tarantula Survey
Extremely broad emission wings at Hβ and Hα have been found in VLT-FLAMES Tarantula Survey data for five very luminous BA supergiants in or near 30 Doradus in the Large Magellanic Cloud. The profiles of both lines are extremely asymmetrical, which we have found to be caused by very broad diffuse interstellar bands (DIBs) in the longward wing of Hβ and the shortward wing of Hα. These DIBs are well known to interstellar but not to many stellar specialists, so that the asymmetries may be mistaken for intrinsic features. The broad emission wings are generally ascribed to electron scattering, although we note difficulties for that interpretation in some objects. Such profiles are known in some Galactic hyper/supergiants and are also seen in both active and quiescent Luminous Blue Variables (LBVs). No prior or current LBV activity is known in these 30 Dor stars, although a generic relationship to LBVs is not excluded; subject to further observational and theoretical investigation, it is possible that these very luminous supergiants are approaching the LBV stage for the first time. Their locations in the HRD and presumed evolutionary tracks are consistent with that possibility. The available evidence for spectroscopic variations of these objects is reviewed, while recent photometric monitoring does not reveal variability. A search for circumstellar nebulae has been conducted, with an indeterminate result for one of them
A study of the validation of RF energy specific absorption rates for simulations of anatomically correct head FDTD simulations and truncated DASY4 standard equipment measurements
This paper presents results of a study concerning the
modification of a generic DASY4 twin phantom SAR
kit (designed for measurements of mobile phones held
to the ear) to facilitate SAR measurements of personal
data assistant mobile communications equipment held in
front of the face. The source used was a half
wavelength dipole illuminating a SAM phantom face.
Two half heads bonded together were used and the
effect of removing the rearmost part of the phantom
head were considered. Results from FDTD simulations
show the effects of the modification. When a 60mm
section is removed from the back of the head, the 1g and
10g SAR values at 900MHz deviate by about 2.4% and
at 1800MHz by about 0.3% from the values obtained
with the full head
Professor Jim James...a great researcher and motivator in the field of antennas
This paper is dedicated to Professor Jim James. It is a
celebration of his life, career and world renowned research
contribution to the engineering community. Jim was eminent
for his pioneering research contributions to the fundamental
understanding of radiation mechanisms in printed patch and
small antennas including seminal achievements, both
theoretical and in terms of demonstrated practical
applications, in communications, radar and medical
electronics. The paper includes a brief summary of his
research. Details will also be included on some of his latest
work involving low SAR material coated mobile handset
antennas
Effect of a Cognitive Aid on Adherence to Perioperative Assessment and Management Guidelines for the Cardiac Evaluation of Noncardiac Surgical Patients
The 2007 American College of Cardiologists/American Heart Association Guidelines on Perioperative Cardiac Evaluation and Care for Noncardiac Surgery is the standard for perioperative cardiac evaluation. Recent work has shown residents and anesthesiologists do not apply these guidelines when tested. This research hypothesized that a decision support tool would improve adherence to this consensus guideline
Estimating individual lifetime risk of incident cardiovascular events in adults with type 2 diabetes: an update and geographical calibration of the DIAbetes Lifetime perspective model (DIAL2)
Background:
The 2021 ESC cardiovascular disease (CVD) prevention guidelines recommend the use of (lifetime) risk prediction models to aid decisions regarding intensified preventive treatment options in adults with type 2 diabetes, e.g. the DIAbetes Lifetime perspective model (DIAL model). The aim of this study was to update the DIAL-model using contemporary and representative registry data (DIAL2) and to systematically calibrate the model for use in other European countries.
Methods and Results:
The DIAL2 model was derived in 467,856 people with type 2 diabetes without a history of CVD from the Swedish National Diabetes Register, with a median follow-up of 7.3 years (IQR 4.0-10.6 years) and comprising 63,824 CVD (including fatal CVD, nonfatal stroke and nonfatal myocardial infarction) events and 66,048 non-CVD mortality events. The model was systematically recalibrated to Europe’s low and moderate risk region using contemporary incidence data and mean risk factor distributions. The recalibrated DIAL2 model was externally validated in 218,267 individuals with type 2 diabetes from the Scottish Care Information – Diabetes (SCID) and Clinical Practice Research Datalink (CPRD). In these individuals, 43,074 CVD events and 27,115 non-CVD fatal events were observed. The DIAL2 model discriminated well, with C-indices of 0.732 (95%CI 0.726-0.739) in CPRD and 0.700 (95%CI 0.691-0.709) in SCID.
Interpretation:
The recalibrated DIAL2 model provides a useful tool for the prediction of CVD-free life expectancy and lifetime CVD risk for people with type 2 diabetes without previous CVD in the European low and moderate risk regions. These long-term individualized measures of CVD risk are well suited for shared decision making in clinical practice as recommended by the 2021 CVD ESC prevention guidelines
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