Simulations of Protoplanetary Disk Dispersal: Stellar Mass Dependence of the Disk Lifetime

Recent infrared and submillimeter observations suggest that the protoplanetary disk lifetime depends on the central stellar mass. The disk dispersal is thought to be driven by viscous accretion, magneto-hydrodynamics (MHD) winds, and photoevaporation by the central star. We perform a set of one-dimensional simulations of long-term disk evolution that include all the three processes. We vary the stellar mass in the range of 0.5-7M$_{\odot}$, and study the mass dependence of the disk evolution. We show that a significant fraction of the disk gas is lost by MHD winds in the early stage, but the later disk evolution is mainly governed by photoevaporation. The disk radius decreases as photoevaporation clears out the gas in the outer disk efficiently. The qualitative evolutionary trends of the disk mass are remarkably similar for the wide range of the central stellar mass we consider, and the time evolution of the disk mass can be well fitted by a simple function. The dispersal time is approximately ten million years for low mass stars with weak mass dependence, but gets as short as two million years around a 7M$_{\odot}$ star. In the latter case, a prominent inner hole is formed by the combined effect of accretion and MHD winds within about one million years. The strength of the MHD wind and viscous accretion controls the overall mass-loss rate, but does not alter the dependence of the dispersal timescale on the central stellar mass.Comment: 14 pages, 10 figures, 1 tabl

Comparison of responsiveness of the Japanese Society for Surgery of the Hand version of the carpal tunnel syndrome instrument to surgical treatment with DASH, SF-36, and physical findings

AbstractBackgroundThe Japanese Society for Surgery of -the Hand version of the Carpal Tunnel Syndrome Instrument (CTSI-JSSH), which consists of two parts — one for symptom severity (CTSI-SS) and the other for functional status (CTSI-FS) — is a self-administered questionnaire specifically designed for carpal tunnel syndrome. The responsiveness of the CTSI-JSSH was compared with that of the JSSH version of the Disability of Arm, Shoulder, and Hand questionnaire (DASH), the official Japanese version of the 36-Item Short Form Health Survey (SF-36, version 1.2), and physical examinations to elucidate the role of the CTSI-JSSH for evaluating patients with carpal tunnel syndrome.MethodsPreoperatively, a series of 60 patients with carpal tunnel syndrome completed the CTSI-JSSH, DASH, and SF-36. Results of physical examinations, including grip strength, pulp pinch, and static two-point discrimination of the thumb, index, and long fingers, were recorded. Three months after carpal tunnel release surgery the patients were asked to fill out the same questionnaires, and the physical examinations were repeated. The responsiveness of all the instruments was examined by calculating the standardized response mean (SRM) and effect size (ES). Correlation coefficients were calculated between questionnaire change scores and patient satisfaction scores as well as between the CTSI change scores and those of the DASH and SF-36.ResultsThe largest responsiveness was observed in the CTSI-SS (SRM/ES: −1.00/−1.08) followed by the CTSI-FS (−0.76/−0.63), and bodily pain subscale of SF-36 (SF−36−BP, 0.45/0.55), and the DASH (−0.46/−0.47). Only the change scores of the CTSI-SS had significant correlation with patient satisfaction (r = 0.34, P < 0.01). An absolute value of Spearman’s correlation coefficient of >0.5 was observed between the change scores of the CTSI-SS and the DASH, the CTSI-SS and the SF-36-BP, the CTSI-FS and the DASH, and the DASH and the SF-36-BP.ConclusionThe CTSI-JSSH was proven to be more sensitive to clinical changes after carpal tunnel release than the other outcome measures and should be used to evaluate patients with carpal tunnel syndrome who speak Japanese as their native language

2-D Heat Transfer Model of A Horizontal U-Tube

Paying attention to the shallow ground heat inside a tunnel, a Horizontal U-Tube (HUT) road heating system was introduced for the first time in Japan in order to prevent winter traffic accidents associated with road freezing at the west side mouth of Nanaori-Toge tunnel, Aizu-bange, Fukushima Prefecture. Horizontal U-tubes were buried at a depth of 1.2 m in the ground of the central part of the tunnel. The ground heat extracted by the HUT is injected into the anti-freezing pavement at the tunnel mouth. In this study, attempts were made to propose a simplified heat transfer model of HUT system. The proposed model consists of the energy balance equations of the fluid circulating in the HUT and the surrounding ground. Solving these two equations simultaneously, the extracted ground heat could be calculated as well as the fluid and ground temperatures. The model could also lead the overall heat transfer coefficient between the fluid and the surrounding ground. The validity of the model was accepted from the comparison with indoor experimental results using a miniature HUT

2-D Heat Transfer Model of A Horizontal U-Tube

Paying attention to the shallow ground heat inside a tunnel, a Horizontal U-Tube (HUT) road heating system was introduced for the first time in Japan in order to prevent winter traffic accidents associated with road freezing at the west side mouth of Nanaori-Toge tunnel, Aizu-bange, Fukushima Prefecture. Horizontal U-tubes were buried at a depth of 1.2 m in the ground of the central part of the tunnel. The ground heat extracted by the HUT is injected into the anti-freezing pavement at the tunnel mouth. In this study, attempts were made to propose a simplified heat transfer model of HUT system. The proposed model consists of the energy balance equations of the fluid circulating in the HUT and the surrounding ground. Solving these two equations simultaneously, the extracted ground heat could be calculated as well as the fluid and ground temperatures. The model could also lead the overall heat transfer coefficient between the fluid and the surrounding ground. The validity of the model was accepted from the comparison with indoor experimental results using a miniature HUT

Two-color photoassociation spectroscopy of ytterbium atoms and the precise determinations of s-wave scattering lengths

By performing high-resolution two-color photoassociation spectroscopy, we have successfully determined the binding energies of several of the last bound states of the homonuclear dimers of six different isotopes of ytterbium. These spectroscopic data are in excellent agreement with theoretical calculations based on a simple model potential, which very precisely predicts the s-wave scattering lengths of all 28 pairs of the seven stable isotopes. The s-wave scattering lengths for collision of two atoms of the same isotopic species are 13.33(18) nm for ^{168}Yb, 3.38(11) nm for ^{170}Yb, -0.15(19) nm for ^{171}Yb, -31.7(3.4) nm for ^{172}Yb, 10.55(11) nm for ^{173}Yb, 5.55(8) nm for ^{174}Yb, and -1.28(23) nm for ^{176}Yb. The coefficient of the lead term of the long-range van der Waals potential of the Yb_2 molecule is C_6=1932(30) atomic units $(E_h a_0^6 \approx 9.573\times 10^{-26}$ J nm^6).Comment: 9 pages, 7 figure

Specific Heat Study of Non-Fermi Liquid Behavior in CeNi_2Ge_2: Anomalous Peak in Quasi-Particle Density-of-States

To investigate the non-Fermi liquid (NFL) behavior in a nonalloyed system CeNi_2Ge_2, we have measured the temperature and field dependences of the specific heat C on a CeNi_2Ge_2 single crystal. The distinctive temperature dependence of C/T (~a-b*T^(1/2)) is destroyed in almost the same manner for both field directions of B//c-axis and B//a-axis. The overall behavior of C(T,B) and the low-temperature upturn in magnetic susceptibility can be reproduced, assuming an anomalous peak of the quasi-particle-band density-of-states (DOS) at the Fermi energy possessing (epsilon)^(1/2) energy dependence. Absence of residual entropy around T=0 K in B~0 T has been confirmed by the magnetocaloric effect measurements, which are consistent with the present model. The present model can also be applied to the NFL behavior in CeCu_{5.9}Au_{0.1} using a ln(epsilon)-dependent peak in the DOS. Possible origins of the peak in the DOS are discussed.Comment: 4 pages, LaTeX, using jpsj.sty, to be published in J. Phys. Soc. Jpn. 66 No. 10 (1997), 7 figures available at http://494-475.phys.metro-u.ac.jp/ao/ceni2ge2.htm

Benefit of adjuvant immunotherapy in renal cell carcinoma: A myth or a reality?

Background The benefit of adjuvant immunotherapy after nephrectomy in renal cell carcinoma (RCC) is controversial. The present study aimed to examine the possible benefit of adjuvant immunotherapy in various clinical settings. Methods We retrospectively reviewed 436 patients with pT1-3N0-2M0 RCC who underwent radical or partial nephrectomy with curative intent at our institution between 1981 and 2009. Of them, 98 (22.5%) patients received adjuvant interferon-α (IFN-α) after surgery (adjuvant IFN-α group), while 338 (77.5%) did not (control group). The primary endpoint was cancer-specific survival (CSS). Univariate and multivariate analyses were conducted using log-rank tests and Cox proportional hazards models, respectively. Results Fifty-two (11.9%) patients died from RCC with a median follow-up period of 96 months. Preliminary univariate analyses comparing CSS among treatment groups in each TNM setting revealed that CSS in the control group was equal or superior to that in the adjuvant IFN-α group in earlier stages, while the opposite trend was observed in more advanced stages. We evaluated the TNM cutoffs and demonstrated maximized benefit of adjuvant IFN-α in patients with pT2b-3cN0 (P = 0.0240). In multivariate analysis, ôpT3 and pN1-2 were independent predictors for poor CSS in all patients. In the subgroups with ôpT2 disease (n = 123), pN1-2 and no adjuvant treatment were significant poor prognostic factors. Conclusions Adjuvant immunotherapy after nephrectomy may be beneficial in pT2b-3cN0 RCC. Careful consideration is, however, required for interpretation of this observational study because of its selection bias and adverse effects of IFN-α

Interaction and filling induced quantum phases of dual Mott insulators of bosons and fermions

Many-body effects are at the very heart of diverse phenomena found in condensed-matter physics. One striking example is the Mott insulator phase where conductivity is suppressed as a result of a strong repulsive interaction. Advances in cold atom physics have led to the realization of the Mott insulating phases of atoms in an optical lattice, mimicking the corresponding condensed matter systems. Here, we explore an exotic strongly-correlated system of Interacting Dual Mott Insulators of bosons and fermions. We reveal that an inter-species interaction between bosons and fermions drastically modifies each Mott insulator, causing effects that include melting, generation of composite particles, an anti-correlated phase, and complete phase-separation. Comparisons between the experimental results and numerical simulations indicate intrinsic adiabatic heating and cooling for the attractively and repulsively interacting dual Mott Insulators, respectively