1,496 research outputs found
Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration
Projects of the scope of the restoration of the Florida Everglades require substantial
information regarding ecological mechanisms, and these are often poorly understood. We provide critical
base knowledge for Everglades restoration by characterizing the existing vegetation communities of an
Everglades remnant, describing how present and historic hydrology affect wetland vegetation community
composition, and documenting change from communities described in previous studies. Vegetation
biomass samples were collected along transects across Water Conservation Area 3A South (3AS)
A Novel Scheme to Search for Fractional Charge Particles in Low Energy Accelerator Experiments
In the Standard Model of particle physics, the quarks and anti-quarks have
fractional charge equal to or of the electron's charge. There
has been a large number of experiments searching for fractional charge,
isolatable, elementary particles using a variety of methods, including
collisions using dE/dx ionization energy loss measurements, but no evidence has
been found to confirm existence of free fractional charge particles, which
leads to the quark confinement theory. In this paper, a proposal to search for
this kind particles is presented, which is based on the conservation law of
four-momentum. Thanks to the CLEOc and BESIII detectors' large coverage, good
particle identification, precision measurements of tracks' momenta and their
large recorded data samples, these features make the scheme feasible in
practice. The advantage of the scheme is independent of any theoretical models
and sensitive for a small fraction of the quarks transitioning to the
unconfinement phase from the confinement phase.Comment: 9 page
The Active Traveling Wave in the Cochlea
A sound stimulus entering the inner ear excites a deformation of the basilar
membrane which travels along the cochlea towards the apex. It is well
established that this wave-like disturbance is amplified by an active system.
Recently, it has been proposed that the active system consists of a set of
self-tuned critical oscillators which automatically operate at an oscillatory
instability. Here, we show how the concepts of a traveling wave and of
self-tuned critical oscillators can be combined to describe the nonlinear wave
in the cochlea.Comment: 5 pages, 2 figure
Benchmarking with Spine Tango: potentials and pitfalls
The newly released online statistics function of Spine Tango allows comparison of own data against the aggregated results of the data pool that all other participants generate. This comparison can be considered a very simple way of benchmarking, which means that the quality of what one organization does is compared with other similar organizations. The goal is to make changes towards better practice if benchmarking shows inferior results compared with the pool. There are, however, pitfalls in this simplified way of comparing data that can result in confounding. This means that important influential factors can make results appear better or worse than they are in reality and these factors can only be identified and neutralized in a multiple regression analysis performed by a statistical expert. Comparing input variables, confounding is less of a problem than comparing outcome variables. Therefore, the potentials and limitations of automated online comparisons need to be considered when interpreting the results of the benchmarking procedur
Computer aided diagnosis for cardiovascular diseases based on ECG signals : a survey
The interpretation of Electroencephalography (ECG) signals is difficult, because even subtle changes in the waveform can indicate a serious heart disease. Furthermore, these waveform changes might not be present all the time. As a consequence, it takes years of training for a medical practitioner to become an expert in ECG-based cardiovascular disease diagnosis. That training is a major investment in a specific skill. Even with expert ability, the signal interpretation takes time. In addition, human interpretation of ECG signals causes interoperator and intraoperator variability. ECG-based Computer-Aided Diagnosis (CAD) holds the promise of improving the diagnosis accuracy and reducing the cost. The same ECG signal will result in the same diagnosis support regardless of time and place. This paper introduces both the techniques used to realize the CAD functionality and the methods used to assess the established functionality. This survey aims to instill trust in CAD of cardiovascular diseases using ECG signals by introducing both a conceptional overview of the system and the necessary assessment method
Production, Collection and Utilization of Very Long-Lived Heavy Charged Leptons
If a fourth generation of leptons exists, both the neutrino and its charged
partner must be heavier than 45 GeV. We suppose that the neutrino is the
heavier of the two, and that a global or discrete symmetry prohibits
intergenerational mixing. In that case, non-renormalizable Planck scale
interactions will induce a very small mixing; dimension five interactions will
lead to a lifetime for the heavy charged lepton of years. Production
of such particles is discussed, and it is shown that a few thousands can be
produced and collected at a linear collider. The possible uses of these heavy
leptons is also briefly discussed.Comment: 9 pages Late
Self-tuning to the Hopf bifurcation in fluctuating systems
The problem of self-tuning a system to the Hopf bifurcation in the presence
of noise and periodic external forcing is discussed. We find that the response
of the system has a non-monotonic dependence on the noise-strength, and
displays an amplified response which is more pronounced for weaker signals. The
observed effect is to be distinguished from stochastic resonance. For the
feedback we have studied, the unforced self-tuned Hopf oscillator in the
presence of fluctuations exhibits sharp peaks in its spectrum. The implications
of our general results are briefly discussed in the context of sound detection
by the inner ear.Comment: 37 pages, 7 figures (8 figure files
History of exotic Meson (4-quark) and Baryon (5-quark) States
I briefly review the history of exotic meson (4-quark) and baryon (5-quark)
states, which is rooted in the formalism of Regge pole and duality. There are
robust model-independent predictions for the exchange of 4-quark (Baryonium)
Regge trajectories in several processes, which are strongly supported by
experiment. On the other hand the predictions for the spectroscopy of 4-quark
resonances are based on specific QCD inspired models, with some experimental
support. The corresponding predictions for the recently discovered exotic
baryon (Pentaquark) state are briefly discussed.Comment: 14 pages Latex including 4 eps figures, final version to appear as a
topical review in J. Phys.
Exploring the QCD landscape with high-energy nuclear collisions
Quantum chromodynamics (QCD) phase diagram is usually plotted as temperature
(T) versus the chemical potential associated with the conserved baryon number
(\mu_{B}). Two fundamental properties of QCD, related to confinement and chiral
symmetry, allows for two corresponding phase transitions when T and \mu_{B} are
varied. Theoretically the phase diagram is explored through non-perturbative
QCD calculations on lattice. The energy scale for the phase diagram
(\Lambda_{QCD} ~ 200 MeV) is such that it can be explored experimentally by
colliding nuclei at varying beam energies in the laboratory. In this paper we
review some aspects of the QCD phase structure as explored through the
experimental studies using high energy nuclear collisions. Specifically, we
discuss three observations related to the formation of a strongly coupled
plasma of quarks and gluons in the collisions, experimental search for the QCD
critical point on the phase diagram and freeze-out properties of the hadronic
phase.Comment: Submitted to the New Journal of Physics focus issue "Strongly
Correlated Quantum Fluids: From Ultracold Quantum Gases to QCD Plasmas
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