10,233 research outputs found
Correlation of hippocampal theta rhythm with changes in cutaneous temperature
A possible role for the hippocampus in alerting an animal to changes in cutaneous temperature was examined. Following local warming or cooling of the ears of unanesthetized, loosely restrained rabbits, theta waves (4-7 Hz EEG waves) were recorded from electrodes straddling the hippocampus. The onset of the hippocampal theta rhythm was correlated with changes in cutaneous temperature, an observation consistent with studies indicating that the theta rhythm is a nonspecific response evoked by stimulation of several sensory modalities. Additional data from cats and rabbits were correlated with specific neurons within the hippocampus, namely pyramidal cells. Post stimulus time histograms obtained by excitation of the dorsal fornix were interpreted in terms of excitatory and inhibitory inputs to pyramidal cells. Thus, the theta rhythm, which appears to be evoked by changes in cutaneous temperature, can be related to a specific type of hippocampal neuron which is in turn connected with other areas of the brain involved in temperature regulation
Ranking Significant Discrepancies in Clinical Reports
Medical errors are a major public health concern and a leading cause of death
worldwide. Many healthcare centers and hospitals use reporting systems where
medical practitioners write a preliminary medical report and the report is
later reviewed, revised, and finalized by a more experienced physician. The
revisions range from stylistic to corrections of critical errors or
misinterpretations of the case. Due to the large quantity of reports written
daily, it is often difficult to manually and thoroughly review all the
finalized reports to find such errors and learn from them. To address this
challenge, we propose a novel ranking approach, consisting of textual and
ontological overlaps between the preliminary and final versions of reports. The
approach learns to rank the reports based on the degree of discrepancy between
the versions. This allows medical practitioners to easily identify and learn
from the reports in which their interpretation most substantially differed from
that of the attending physician (who finalized the report). This is a crucial
step towards uncovering potential errors and helping medical practitioners to
learn from such errors, thus improving patient-care in the long run. We
evaluate our model on a dataset of radiology reports and show that our approach
outperforms both previously-proposed approaches and more recent language models
by 4.5% to 15.4%.Comment: ECIR 2020 (short
Electronic and optical properties in non-uniformly shaped QDashes
We theoretically study the optical properties and the electronic structure of
highly elongated quantum dots (quantum dashes) and show how carrier trapping
due to geometrical fluctuations of the confining potential affects the
excitonic spectrum of the system. We focus on the study of the optical
properties of a single exciton confined in the structure. The dependence of the
absorption and emission intensities on the geometrical properties (depth and
position) of the trapping center of a quantum dash is analyzed and the
dependence of the degree of linear polarization on these geometrical parameters
is studied in detail.Comment: 17 pages, 9 figure
Study of strongly interacting particle in the cosmic radiation at sea level using a flash tube chamber
A measurement of the energy spectrum of hadrons at sea level in the energy range 10 GeV to 10 TeV has been performed. The hadrons interacted in a thick iron or lead absorber and the burst size produced was detected by a scintillation counter placed under each absorber. The burst sizes were used to estimate the energy of hadrons. The result on the hadron energy spectrum shows a constant slope of the form E(^-2.7±0.1) over the whole energy range from 10 GeV to 10 TeV. There is no change or step in the slope between 2-8 TeV as has been suggested by Baruch et al, (1973), A measurement of the energy spectrum of neutrons at sea level in the energy range 50-1,00GeV has been made and the experimental result represented as a differential energy spectrum in the form N(E) = K(^--2.9±0.1) in the same energy range. This result agrees with previous Durham neutron spectrum measurements. A statistical method has been used to derive the high energy pion flux at sea level from the total measured hadron spectrum. The results show an increase in the π/p ratio as the energy increases and over the energy range 40 GeV to 7 TeV the differential vertical flux decreases with increasing energy as E(-2.55±0.10). A search for (^e)/(_3) charged particles (quarks) close to the core of air showers of median size 6o5 10^ particles has been carried out. The search was conducted at sea level using a flash tube chamber technique as a visible detector. Air showers were selected in this experiment by requiring a local electron density above the chamber to be greater than 250 m(^-2). In 7,009 hours two quark candidates were observed and both were explained as duo to background incoherent muons. With no definite quark tracks having been observed, the upper limit on the (^e)/(_3) quark flux is 200 GeV
Search for quarks using a flash tube chamber
A large flash tube chamber has been used at Durham to search-for e/3 charged particles (quarks) in extensive air showers where the local electron density is greater than 40m(^-2). The response of the detector to relativistic muons was measured and the equivalent characteristics for relativistic e/3 quarks calculated. The response for the more energetic muons in air showers was also measured. In a running time of 2,570 hours no definite quark tracks have been detected and the limit on the charge e/3 quark flux was set as: I<8.0 10(^-11) cm(^-2) sec(^-1) st(^-1). No non relativistic heavy mass particles, irrespective of their charge, were detected in the chamber from measurements on two body elastic collisions of EAS particles with essentially free protons
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