946 research outputs found
Synchronization learning of coupled chaotic maps
We study the dynamics of an ensemble of globally coupled chaotic logistic
maps under the action of a learning algorithm aimed at driving the system from
incoherent collective evolution to a state of spontaneous full synchronization.
Numerical calculations reveal a sharp transition between regimes of
unsuccessful and successful learning as the algorithm stiffness grows. In the
regime of successful learning, an optimal value of the stiffness is found for
which the learning time is minimal
Maxillary nerve block: A comparison between the greater palatine canal and high tuberosity approaches.
Aim: Analgesia and anxiolysis during dental procedures are important for dental care and
patient compliance. This study aims to compare two classical maxillary nerve block (MNB)
techniques: the greater palatine canal (GPC) and the high tuberosity (HT) approaches,
seldom used in routine dental practice.
Methods: The study was conducted on 30 patients, scheduled for sinus lift surgery, who
were randomly divided into 2 groups: the GPC approach to the MNB was used in 15 and the
HT one in the other 15 patients. Anxiolysis was also used, depending on the results of the
pre- preoperative assessment. Patients\u2019 sensations/pain during the procedure, details about
anesthesia, and the dentist\u2019s considerations were all recorded. Data are expressed as mean
\ub1SD. Statistical tests including ANOVA, \u3c72 following Yates correction and linear regression
analysis were carried out. A < 0.05 p value was considered significant.
Results: Study results showed that the anesthesia was effective and constant in the molar
and premolar area. Additional infiltrations of local anesthetics were necessary for vestibular
and palatal areas in the anterior oral cavity, respectively, in the GPC and HT groups. The
two techniques were equally difficult to carry out in the dentist\u2019s opinion. There were
no differences in pain or unpleasant sensations between the two groups, nor were any
anesthesia-related complications reported.
Conclusion: The GPC approach ensures effective anesthesia in the posterior maxillary
region as far as both the dental pulp and the palatal/vestibular mucous membranes are
concerned; the HT approach did not guarantee adequate anesthesia of the pterygopalatine
branch of the maxillary nerve. These regional anesthesia techniques were characterized
by a low incidence of intra and postoperative pain, no noteworthy complications, and high
patient satisfaction
Oral malodor in Special Care Patients: current knowledge
Epidemiological studies report that about 50% of the population may have oral malodor
with a strong social and psychological impact in their daily life. When intra-oral causes are
excluded, referral to an appropriate medical specialist is paramount for management and
treatment of extra-oral causes. The intra-oral causes of halitosis are highly common, and the
dentist is the central clinician to diagnose and treat them. Pseudohalitosis or halitophobia
may occur and an early identification of these conditions by the dentist is important in order
to avoid unnecessary dental treatments for patients who need psychological or psychiatric
therapy. The organoleptic technique is still considered the most reliable examination method
to diagnose genuine halitosis. Special needs patients are more prone than others to have
oral malodor because of concurrent systemic or metabolic diseases, and medications.
The present report reviews halitosis, its implications, and the management in special care
dentistry
Demographic growth and the distribution of language sizes
It is argued that the present log-normal distribution of language sizes is,
to a large extent, a consequence of demographic dynamics within the population
of speakers of each language. A two-parameter stochastic multiplicative process
is proposed as a model for the population dynamics of individual languages, and
applied over a period spanning the last ten centuries. The model disregards
language birth and death. A straightforward fitting of the two parameters,
which statistically characterize the population growth rate, predicts a
distribution of language sizes in excellent agreement with empirical data.
Numerical simulations, and the study of the size distribution within language
families, validate the assumptions at the basis of the model.Comment: To appear in Int. J. Mod. Phys. C (2008
O plastocrono e o filocrono em Araucaria angustifolia (Bert.) O. Ktze., no município de Colombo, Paraná.
EVINCI. Resumo 014
Interacting Individuals Leading to Zipf's Law
We present a general approach to explain the Zipf's law of city distribution.
If the simplest interaction (pairwise) is assumed, individuals tend to form
cities in agreement with the well-known statisticsComment: 4 pages 2 figure
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