2,631 research outputs found
The Effect of EDTA in Attachment Gain and Root Coverage
Root surface biomodification using low pH agents such as citric acid and tetracycline has been proposed to enhance root coverage following connective tissue grafting. The authors hypothesized that root conditioning with neutral pH edetic acid would improve vertical recession depth, root surface coverage, pocket depth, and clinical attachment levels. Twenty teeth in 10 patients with Miller class I and II recession were treated with connective tissue grafting. The experimental sites received 24% edetic acid in sterile distilled water applied to the root surface for 2 minutes before grafting. Controls were pretreated with only sterile distilled water. Measurements were evaluated before surgery and 6 months after surgery. Analysis of variance was used to determine differences between experimental and control groups. We found significant postoperative improvements in vertical recession depth, root surface coverage, and clinical attachment levels in test and control groups, compared to postoperative data. Pocket depth differences were not significant (P\u3c.01)
Sexual Reward and Depression
Sexual behavior in male rats is a complex rewarding behavior and many neurotransmitters and neuropeptides play an important role in mediation of sexual performance, motivation and reward. The hypothalamic neuropeptide orexin has been shown play a key role in reward associated with food and drugs of abuse, but the role of this neuropeptide in control of sexual performance, motivation and reward is currently unclear. First, it was shown that orexin neurons in the hypothalamus are activated during sexual performance and reward. Next, using cell specific lesions of orexin neurons it was demonstrated that orexin is involved in arousal and anxiety, but is not critical for sexual performance or motivation. Moreover, orexin was shown to play a critical role in control of sexual reward. Thus, these studies provided novel information regarding a role for orexin in this natural reward behavior. Recent studies have shown that sexual behavior in male rats causes neuroplasticity in the mesolimbic system, enhanced psychostimulant-induced locomotor activity and drug craving. The latter of which is dependent on a period of abstinence from sexual behavior, suggesting an increased vulnerability for addiction following loss of sexual reward. Thus, the next goal of this thesis determined if abstinence from sexual behavior also leads increased vulnerability for other disorders related to reward processing, specifically depression-like behavior. It was demonstrated that a prolonged (28 day) but not short (1 or 7 day) period of abstinence causes depression-like behavior in sexually experienced male rats seen as increased passive stress coping behaviors and anhedonia. Development of depression-like behavior was associated with increased levels of corticotropin releasing factor mRNA in the paraventricular nucleus of the hypothalamus and increased hypothalamic-pituitary-adrenal axis activity in response to an acute stressor. Thus, these studies provide novel information on behavioral and neuroplastic alterations observed following a prolonged period of abstinence from mating and suggest that loss of sexual reward in male rats may be a paradigm to study depression following loss of social reward in humans
Analysis of the Performance of Two Component Back-filling Grout in Tunnel Boring Machines Operating under Face Pressure
Effective-one-body waveforms for binary neutron stars using surrogate models
Gravitational-wave observations of binary neutron star systems can provide
information about the masses, spins, and structure of neutron stars. However,
this requires accurate and computationally efficient waveform models that take
<1s to evaluate for use in Bayesian parameter estimation codes that perform
10^7 - 10^8 waveform evaluations. We present a surrogate model of a nonspinning
effective-one-body waveform model with l = 2, 3, and 4 tidal multipole moments
that reproduces waveforms of binary neutron star numerical simulations up to
merger. The surrogate is built from compact sets of effective-one-body waveform
amplitude and phase data that each form a reduced basis. We find that 12
amplitude and 7 phase basis elements are sufficient to reconstruct any binary
neutron star waveform with a starting frequency of 10Hz. The surrogate has
maximum errors of 3.8% in amplitude (0.04% excluding the last 100M before
merger) and 0.043 radians in phase. The version implemented in the LIGO
Algorithm Library takes ~0.07s to evaluate for a starting frequency of 30Hz and
~0.8s for a starting frequency of 10Hz, resulting in a speed-up factor of ~10^3
- 10^4 relative to the original Matlab code. This allows parameter estimation
codes to run in days to weeks rather than years, and we demonstrate this with a
Nested Sampling run that recovers the masses and tidal parameters of a
simulated binary neutron star system.Comment: 17 pages, 11 figures, submitted to PR
Restoration of abraded and covered marks engraved in steel using active infrared thermography
Plausible fluorescent Ly-alpha emitters around the z=3.1 QSO0420-388
We report the results of a survey for fluorescent Ly-alpha emission carried
out in the field surrounding the z=3.1 quasar QSO0420-388 using the FORS2
instrument on the VLT. We first review the properties expected for fluorescent
Ly-alpha emitters, compared with those of other non-fluorescent Ly-alpha
emitters. Our observational search detected 13 Ly-alpha sources sparsely
sampling a volume of ~14000 comoving Mpc^3 around the quasar. The properties of
these in terms of i) the line equivalent width, ii) the line profile and iii)
the value of the surface brightness related to the distance from the quasar,
all suggest that several of these may be plausibly fluorescent. Moreover, their
number is in good agreement with the expectation from theoretical models. One
of the best candidates for fluorescence is sufficiently far behind QSO0420-388
that it would imply that the quasar has been active for (at least) ~60 Myrs.
Further studies on such objects will give information about proto-galactic
clouds and on the radiative history (and beaming) of the high-redshift quasars.Comment: 10 pages, 4 figures.Update to match the version published on ApJ 657,
135, 2007 March
Interpreting doubly special relativity as a modified theory of measurement
In this article we develop a physical interpretation for the deformed
(doubly) special relativity theories (DSRs), based on a modification of the
theory of measurement in special relativity. We suggest that it is useful to
regard the DSRs as reflecting the manner in which quantum gravity effects
induce Planck-suppressed distortions in the measurement of the "true" energy
and momentum. This interpretation provides a framework for the DSRs that is
manifestly consistent, non-trivial, and in principle falsifiable. However, it
does so at the cost of demoting such theories from the level of "fundamental"
physics to the level of phenomenological models -- models that should in
principle be derivable from whatever theory of quantum gravity one ultimately
chooses to adopt.Comment: 18 pages, plain LaTeX2
The role of mediterranean fruit tree orchards and vineyards in maintaining the traditional agricultural landscape
The Mediterranean area represents one of the most suitable and diversified
environments for horticultural crops, being this propriety well expressed in the
commonly accepted definition of “Mediterranean cultivated garden”. In Italy, fruit
crops have been in the past introduced and expanded in different environments
depending on the species and adaptability to the physiographic characteristics of the
regions. The climate and the diversity of environmental contexts, the specificity of
soils, the plasticity of the cultivated genotypes, have allowed a tight and typical
relationship among land and farmers. Since the past centuries olive and fruit
orchards, vineyards and Citrus plantations have represented the typicity of the Italian
rural landscape. The physiognomy of tree cropping systems has been changed rapidly
starting from half of the past century owing to the introduction of new genetic
resources, the change in the concepts of quality, the modernization and intensification
of the agronomical techniques, resulting in loss of environmental and biological
diversity. Nonetheless, some historic fruit orchards and vineyards have survived. The
research is focused: a) on the recognition and mapping of the traditional landscapes of
fruit crops in two representative Mediterranean regions; b) on the identification of
their typological traits; c) on the definition of their environmental and technical
sustainability based on an interdisciplinary methodology. Through a multi-criterial
analysis it was possible to recognize and measure the sustainability of these cropping
models and their ecological function, turning into preservation of environmental
resources, environmental quality and quality of life. The study also underlined the
crucial role of the traditional agricultural landscapes in the maintenance of local
identity, history and economy. By representing a cultural heritage, traditional agricultural
landscapes and traditional farming might justify preservation and valorisation
actions
Quantum Breathing of an Impurity in a One-dimensional Bath of Interacting Bosons
By means of time-dependent density-matrix renormalization-group (TDMRG) we
are able to follow the real-time dynamics of a single impurity embedded in a
one-dimensional bath of interacting bosons. We focus on the impurity breathing
mode, which is found to be well-described by a single oscillation frequency and
a damping rate. If the impurity is very weakly coupled to the bath, a
Luttinger-liquid description is valid and the impurity suffers an
Abraham-Lorentz radiation-reaction friction. For a large portion of the
explored parameter space, the TDMRG results fall well beyond the
Luttinger-liquid paradigm.Comment: 10 pages, 7 figures, main text and supplementary material merged in a
single PRB style documen
The general exact solution for the many moments macroscopic approach to extended thermodynamics of polyatomic gases
A new model for Polyatomic and for Dense Gases has been proposed in literature in the last five years in
the framework of Extended Thermodynamics. The case with an arbitrary but fixed number of moments has been
recently studied, both with the kinetic approach than with the macroscopic approach; this last one is
more general and includes the results of the kinetic approach only as a particular case. \\
Scope of the "closure problem" is to find the expression of some arbitrary functions which appear in the
balance equations. Up to now only a recurrence procedure has been published which outlines how to find
the solution of this problem with the macroscopic approach; by using this procedure, a numberable set
of solutions has been found and written explicitly, while we find here the most general exact
solution. It is determined except for some arbirary terms and it is interesting that these terms appear
also in the 24 moments model; so we find here that they are transmitted from the model with 24 moments
to those with an arbitrary number of moments, without any further arbitrary term
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