46 research outputs found
Few Islands Approximation of Hamiltonian System with divided Phase Space
It is well known that typical Hamiltonian systems have divided phase space
consisting of regions with regular dynamics on KAM tori and region(s) with
chaotic dynamics called chaotic sea(s). This complex structure makes rigorous
analysis of such systems virtually impossible and significantly complicates
numerical exploration of their dynamical properties. In this paper we outline a
new approach for the analysis of Hamiltonian systems with divided phase space.
These systems are approximated by a sequence of Hamiltonian systems having an
increasing (but finite) number of KAM islands. The islands in the approximating
systems are sub-islands of the islands in the initial system with an infinite
number of KAM-islands. We apply this approach to two-dimensional billiards and
demonstrate that it works. In particular the statistical characteristics of the
approximating systems tend to the ones for the whole system when the number of
islands in the approximating systems grows. Therefore our approach opens up a
new way for numerical and analytical studies of the dynamics of Hamiltonian
systems with divided phase space.Comment: 8 pages (RevTex), 9 figures; version as accepted by Experimental
Mathematic
Identification of lung sliding: a basic ultrasound technique with a steep learning curve
Introduction. One of the basic premises of sonographic lung imaging is the concept of lung sliding. Identification of clear lung sliding excludes pneumothorax (PTx) at that specific local point. Methods. Fifty-seven 4th year medical students were given a 20-minute lecture on sonographic identification of lung sliding and exclusion of PTx. After the lecture, students were asked to correctly position the probe, identify shown structures and on each attempt (six attempts in a row) state whether lung sliding is present or not. Results. There were 57 students in the sample. Fifty students (87.7%) successfully positioned the probe (all 4 positions) for PTx identification. All but five students (91.2%) recognized the anatomic structures of the thorax. Mean number of correctly identified cases per student was 5.1 ± 1.1. In 292 (85.4%) cases, the answer was correct. In 298 (87.1%) cases, students were confident in the correct answer. Students who were confident in the right answer gave the right answer significantly more often when compared to others (90.3% vs. 52.3%, p < 0.001). Sensitivity of this method for 4th year medical students was 82.6% and its specificity was 87.9%. For correct identification of lung sliding in the sixth attempt, students on average needed 4.5 correct attempts. Conclusion. Our study suggests that 4th year medical students with no prior experience in lung ultrasonography can easily acquire knowledge and skills needed to detect thoracic wall structures and identify lung sliding with a high degree of sensitivity and specificity
Kreativni pokret u učionici kao unapređenje funkcioniranja učenika u različitim područjima
The study focuses on students’ emotion expression during geometry teaching including
creative movement (experimental group or EG) and without it (control group or CG).
The sample (N = 104) was made up of primary school (second-grade) students: 66
were assigned to the EG and 38 to the CG. Of these, 12 students from the EG and
8 from the CG were randomly selected for observation of emotion: type, intensity,
triggering situation, and response of others. For the observed students, the intensity of
emotion expression was also measured by the facial expression recognition software
FaceReader. All of the students self-assessed their contentedness with the teaching.
The students in the EG and the CG expressed various emotions, with joy being the
most prevalent, followed by anger. The most frequent situations triggering joy were
activities in the EG and the CG. The intensity of joy was higher in the EG than in
the CG when assessed by observation, but there was no significant difference when
assessed by FaceReader. The intensity of anger expression was at a similar level in
both groups. Both students and teachers responded to students’ joy expression, but
only the students responded to anger expression in the EG and the CG. The students
in both groups expressed a high level of contentedness with the teaching.Kreativni pokret predstavlja aktivan pristup učenju koji studentima omogućuje
da kroz pokret i ples izraze i kreiraju različite obrazovne sadržaje. Predstavlja
mogućnost integriranja umjetnosti i pokreta u proces učenja. U studijskoj godini
2015./16. provedeno je istraživanje, uključujući i učenike drugog razreda osnovne
škole (N = 104) tijekom nastave Matematike (geometrije). Studijom se pokušalo
utvrditi utvrditi kako je korištenje kreativnoga pokreta povezano s funkcioniranjem
učenika u različitim područjima: kognitivnom, socijalnom, emocionalnom,
tijelu/fizičkom. Te su veze uspostavljene usporedbom skupine učenika u kojoj
je provedena nastava, integrirajući kreativni pokret (eksperimentalnu skupinu)
s grupom učenika u kojoj nastava nije uključivala kreativni pokret (kontrolna
skupina). Podaci su prikupljeni različitim mjernim instrumentima, dok je tjelesna
aktivnost mjerena narukvicama BodyMedia Core. Rezultati, između ostalog,
pokazuju visoko zadovoljstvo nastavnim programom kod obje skupine učenika,
ali veća potrošnja energije i dugoročno poznavanje geometrije u eksperimentalnoj
grupi učenika poučavanih korištenjem kreativnoga pokreta
Regular and Irregular States in Generic Systems
In this work we present the results of a numerical and semiclassical analysis
of high lying states in a Hamiltonian system, whose classical mechanics is of a
generic, mixed type, where the energy surface is split into regions of regular
and chaotic motion. As predicted by the principle of uniform semiclassical
condensation (PUSC), when the effective tends to 0, each state can be
classified as regular or irregular. We were able to semiclassically reproduce
individual regular states by the EBK torus quantization, for which we devise a
new approach, while for the irregular ones we found the semiclassical
prediction of their autocorrelation function, in a good agreement with
numerics. We also looked at the low lying states to better understand the onset
of semiclassical behaviour.Comment: 25 pages, 14 figures (as .GIF files), high quality figures available
upon reques
Administration of intravenous morphine for acute pain in the emergency department inflicts an economic burden in Europe
Background: Acute pain is among the leading causes of referral to the emergency department (ED) in industrialized countries. Its management mainly depends on intensity. Moderateto- severe pain is treated with intravenous (IV) administered opioids, of which morphine is the most commonly used in the ED. We have estimated the burden of IV administration of morphine in the five key European countries (EU5) using a micro-costing approach.
Scope: A structured literature review was conducted to identify clinical guidelines for acute pain management in EU5 and clinical studies conducted in the ED setting. The data identified in this literature review constituted the source for all model input parameters, which were clustered as analgesic (morphine), material used for IV morphine administration, nurse workforce time and management of morphine-related adverse events and IV-related complications.
Findings: The cost per patient of IV morphine administration in the ED ranges between €18.31 in Spain and €28.38 in Germany. If costs associated with the management of morphine-related adverse events and IV-related complications are also considered, the total costs amount to €121.13–€132.43. The main driver of those total costs is the management of IV-related complications (phlebitis, extravasation and IV prescription errors; 73% of all costs) followed by workforce time (14%).
Conclusions: IV morphine provides effective pain relief in the ED, but the costs associated with the IV administration inflict an economic burden on the respective national health services in EU5. An equally rapid-onset and efficacious analgesic that does not require IV administration could reduce this burden
Prehospital monitoring in resuscitation : today and the future
There is growing evidence that early detection and response to physiological deterioration can improve outcome for
patients. Working out-of-hospital, we often find ourselves in diagnostic dilemmas, thus more reliable data could change
our actions as well as give better assessment of patient\u27s condition. Therefore, we are always exploring new perspectives
that could be transferred from experimental laboratory settings to our primary working area in the field to help us improve
decision-making leading to better outcome. In the following sections, we represent our previous studies about the utility
of continuous capnometry and the importance of point-of-care ultrasound in cardiopulmonary resuscitation (CPR), and discuss
about the possible future use of transthoracic and transesophageal ultrasound, point-of-care biochemical monitoring,
tissue oxygen saturation, pupillometry, and mixed and central venous oxygen saturation monitoring in the prehospital setting