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