1,018 research outputs found
Free energy surfaces from nonequilibrium processes without work measurement
Recent developments in statistical mechanics have allowed the estimation of
equilibrium free energies from the statistics of work measurements during
processes that drive the system out of equilibrium. Here a different class of
processes is considered, wherein the system is prepared and released from a
nonequilibrium state, and no external work is involved during its observation.
For such ``clamp-and-release'' processes, a simple strategy for the estimation
of equilibrium free energies is offered. The method is illustrated with
numerical simulations, and analyzed in the context of tethered single-molecule
experiments.Comment: 15 pages, 3 figures (1 color); accepted to J. Chem. Phy
Efektivitas Pembelajaran Biologi Berorientasi Literasi Saintifik
Penelitian ini bertujuan untuk menemukan keefektifan pendekatan saintifik dalam pembelajaran biologi berorientasi literasi saintifik. Subjek dari penelitian ini adalah siswa kelas X program ilmu pengetahuan alam dari salah satu sekolah menengah di Kudus. Keefektifan diukur berdasarkan nilai ukuran efek Cohen d berdasarkan hasil pretest dan posttest yang diambil menggunakan desain deret waktu. Hasil penelitian menunjukkan bahwa keefektifan pendekatan saintifik dalam pembelajaran biologi berorientasi literasi saintifik berada di kategori sedang dengan nilai 0,548. Melalui penelitian ini, terungkap bahwa pendekatan saintifik dapat menjadi tawaran model pembelajaran berorientasi literasi saintifik serta tidak dapat ditemukan model terbaik untuk digunakan dalam pembelajaran ilmu pengetahuan alam termasuk biologi
Path integral analysis of Jarzynski's equality: Analytical results
We apply path integrals to study nonequilibrium work theorems in the context
of Brownian dynamics, deriving in particular the equations of motion governing
the most typical and most dominant trajectories. For the analytically soluble
cases of a moving harmonic potential and a harmonic oscillator with
time-dependent natural frequency, we find such trajectories, evaluate the
work-weighted propagators, and validate Jarzynski's equality.Comment: 10 pages, 1 figur
Symmetry relations in chemical kinetics arising from microscopic reversibility
It is shown that the kinetics of time-reversible chemical reactions having
the same equilibrium constant but different initial conditions are closely
related to one another by a directly measurable symmetry relation analogous to
chemical detailed balance. In contrast to detailed balance, however, this
relation does not require knowledge of the elementary steps that underlie the
reaction, and remains valid in regimes where the concept of rate constants is
ill-defined, such as at very short times and in the presence of low activation
barriers. Numerical simulations of a model of isomerization in solution are
provided to illustrate the symmetry under such conditions, and potential
applications in protein folding-unfolding are pointed out.Comment: 4 pages, 1 figure, accepted to Phys Rev Let
Does the Boltzmann principle need a dynamical correction?
In an attempt to derive thermodynamics from classical mechanics, an
approximate expression for the equilibrium temperature of a finite system has
been derived [M. Bianucci, R. Mannella, B. J. West, and P. Grigolini, Phys.
Rev. E 51, 3002 (1995)] which differs from the one that follows from the
Boltzmann principle S = k log (Omega(E)) via the thermodynamic relation 1/T=
dS/dE by additional terms of "dynamical" character, which are argued to correct
and generalize the Boltzmann principle for small systems (here Omega(E) is the
area of the constant-energy surface). In the present work, the underlying
definition of temperature in the Fokker-Planck formalism of Bianucci et al. is
investigated and shown to coincide with an approximate form of the
equipartition temperature. Its exact form, however, is strictly related to the
"volume" entropy S = k log (Phi(E)) via the thermodynamic relation above for
systems of any number of degrees of freedom (Phi(E) is the phase space volume
enclosed by the constant-energy surface). This observation explains and
clarifies the numerical results of Bianucci et al. and shows that a dynamical
correction for either the temperature or the entropy is unnecessary, at least
within the class of systems considered by those authors. Explicit analytical
and numerical results for a particle coupled to a small chain (N~10) of quartic
oscillators are also provided to further illustrate these facts.Comment: REVTeX 4, 10 pages, 2 figures. Accepted to J. Stat. Phy
Jarzynski Equality for an Energy-Controlled System
The Jarzynski equality (JE) is known as an exact identity for nonequillibrium
systems. The JE was originally formulated for isolated and isothermal systems,
while Adib reported an JE extended to an isoenergetic process. In this paper,
we extend the JE to an energy-controlled system. We make it possible to control
the instantaneous value of the energy arbitrarily in a nonequilibrium process.
Under our extension, the new JE is more practical and useful to calculate the
number of states and the entropy than the isoenergetic one. We also show
application of our JE to a kind of optimization problems.Comment: 6 pages, 1 figur
Analisis Penerapan Single Page Application Menggunakan Teknologi AJAX Dan REST API (Studi Kasus :Sistem Informasi Reservasi Wisma Tamu UKSW)
Developments of web for information system today are really popular. We can access the system from anywhere by internet connection. This paper focus on design of the web application that using Single Page Application concept. Using AJAX technology the application will provide an interactive user experience, also the effective and efficiency USAge of bandwith also be considered. The result of this paper shows that implement Single Page Application concept still make the web bandwith USAge effective and efficient if accessible by user. Keywords— Single Page Application, AJAX, REST API
Effects of a Multimodal Preparation Package on Vital Signs of Patients Waiting for Coronary Angiography
Background: Patients waiting for coronary angiography are often anxious and worried, experiencing considerable emotional problems before the procedure, which can result in an increase in blood pressure (BP), heart rate, respiratory rate and the myocardial oxygen demand. Such maladaptive responses may not only increase the patients need for sedative drugs, but also could increase the length of post angiography hospitalization. Therefore, it is important to implement some supportive actions to decrease the patients’ anxiety and to stabilize their vital signs before coronary angiography.
Objectives: This study aimed to investigate the effects of a multimodal preparation package on vital signs of patients undergoing coronary angiography.
Patients and Methods: A matched trial was conducted on 66 patients waiting for coronary angiography. Patients were assigned in intervention (n = 33) and control (n = 33) groups. A multimodal preparation package was implemented in intervention group, two hours before angiography. The data collection instrument consisted of questions on demographic characteristics and a table for recording the patients’ vital signs including systolic BP (SBP) and diastolic BP (DBP), heart rate, respiratory rate and body temperature. Vital signs were measured three times, the day before angiography, 30 minutes before and 30 minutes after the angiography, using a thermometer and a monitoring device. Data analysis was performed using the Kolmogo-Smirnov test, t test and Mann-Whitney U test.
Results: From the total number of 66 patients, the 63.3% were male and married. No significant differences were observed between the mean of SBP and DBP and also the heart rate in the intervention and control groups, on the day before angiography. However, the mean SBP and DBP and heart rate of the intervention group were significantly lower compared to the control group, both 30 minutes before and 30 minutes after angiography. The intervention did not significantly change the respiration rate and temperature in the intervention group.
Conclusions: The study showed that preparation package was effective in decreasing SBP and DBP, as well as heart rate. Therefore, using multimodal comprehensive preparation packages, such as the package used in the present report, is suggested
Effect of Achillea millefolium Distillate on Recovery Time in Patients with Gastroenteritis
Background: Some animal studies have reported that Achillea millefolium (A. millefolium) extract can affect intestinal movements in rats. However, no study is available on the effect of A. millefolium on recovery from gastroenteritis in human subjects.
Objectives: This study aimed to investigate the effect of A. millefolium on recovery from gastroenteritis in patients over 12 years old.
Patients and Methods: A randomized controlled trial was conducted on 44 patients with gastroenteritis. The patients were randomly assigned to two groups of 22 each. The control group received the usual treatments. In addition to the usual treatments, the intervention group received 0.5 mL/kg of A. millefolium distillate every 8 hours. The duration of recovery was recorded for both groups. Descriptive statistics, Chi-square, Fisher’s exact test, and the t-test were used to compare the two groups.
Results: The mean duration of recovery in the group receiving A. millefolium distillate was 1.31 ± 0.71 days, while it was 1.86 ± 0.71 days in the control group (P = 0.015).
Conclusions: Adding A. millefolium distillate to the usual treatment for simple gastroenteritis was effective in shortening the recovery time
NP-hardness of the cluster minimization problem revisited
The computational complexity of the "cluster minimization problem" is
revisited [L. T. Wille and J. Vennik, J. Phys. A 18, L419 (1985)]. It is argued
that the original NP-hardness proof does not apply to pairwise potentials of
physical interest, such as those that depend on the geometric distance between
the particles. A geometric analog of the original problem is formulated, and a
new proof for such potentials is provided by polynomial time transformation
from the independent set problem for unit disk graphs. Limitations of this
formulation are pointed out, and new subproblems that bear more direct
consequences to the numerical study of clusters are suggested.Comment: 8 pages, 2 figures, accepted to J. Phys. A: Math. and Ge
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