Orbital Order, Structural Transition and Superconductivity in Iron Pnictides

We investigate the 16-band d-p model for iron pnictide superconductors in the presence of the electron-phonon coupling g with the orthorhombic mode which is crucial for reproducing the recently observed ultrasonic softening. Within the RPA, we obtain the ferro-orbital order below TQ which induces the tetragonal-orthorhombic structural transition at Ts = TQ, together with the stripe-type antiferromagnetic order below TN. Near the phase transitions, the system shows the s++ wave superconductivity due to the orbital fluctuation for a large g case with TQ > TN, while the s+- wave due to the magnetic fluctuation for a small g case with TQ < TN. The former case is consistent with the phase diagram of doped iron pnictides with Ts > TN.Comment: 5 pages, 5 figures, minor changes, published in J. Phys. Soc. Jp

A Strategic Management Learning Laboratory: Integrating the College Classroom and the College Human Resource Management Environment

This capstone course extended the classroom to include practitioner-focused research projects and presentations to senior-level campus management. The course served as a student learning laboratory for experiencing working-world settings, problems, and expectations, using the controlled environment of a college human resource management office, working with the Director of Human Resource Management. Learning outcomes included 1) effectively using multiple business communication skills, 2) applying quantitative and qualitative reasoning for problem solving to integrate, synthesize and apply complex information for addressing practical problems; 3) experience in adapting to a real-life, changing environment, and 4) making management decisions that reflected the dynamic interrelationships of the major functions of business to achieve the mission of the organization. Finally, students reported a heightened sense of task identity, personal commitment to their college and their education, and a legacy of contribution for their role in helping shape human resource management policies for college governance

Fundamental properties of Tsallis relative entropy

Fundamental properties for the Tsallis relative entropy in both classical and quantum systems are studied. As one of our main results, we give the parametric extension of the trace inequality between the quantum relative entropy and the minus of the trace of the relative operator entropy given by Hiai and Petz. The monotonicity of the quantum Tsallis relative entropy for the trace preserving completely positive linear map is also shown without the assumption that the density operators are invertible. The generalized Tsallis relative entropy is defined and its subadditivity is shown by its joint convexity. Moreover, the generalized Peierls-Bogoliubov inequality is also proven

Structures and functions of carotenoids bound to reaction centers from purple photosynthetic bacteria

The photoprotective function of 15,15'-cis-carotenoids bound to the photosynthetic reaction centers (RCs) of purple bacteria has been studied using carotenoids reconstituted into carotenoidless RCs from Rhodobacter sphaeroides strain R26.1. The triplet-energy level of the carotenoid has been proposed to affect the quenching of the triplet state of special-pair bacteriochlorophyll (P). This was investigated using microsecond flash photolysis to detect the carotenoid triplets as a function of the number of conjugated double bonds, n. The carotenoid triplet signals were extracted by using singular-value decomposition (SVD) of the huge matrices data, and were confirmed for those having n = 8 to 11. This interpretation assumes that the reconstituted carotenoids occupy the same binding site in the RC. We have been able to confirm this assumption using X-ray crystallography to determine the structures of carotenoidless, wild-type carotenoid-containing, and 3,4-dihydro-spheroidene-reconstituted RCs. The X-ray study also emphasized the importance of the methoxy group of the carotenoids for binding to the RCs. Electroabsorption (Stark) spectroscopy was used to investigate the effect of the carotenoid on the electrostatic field around P. This electrostatic field changed by 10 % in the presence of the carotenoid

Study of Ni-doping Effect of Specific Heat and Transport Properties for LaFe1-yNiyAsO0.89F0.11

Specific heats and transport quantities of the LaFe1-yNiyAsO0.89F0.11 system have been measured, and the results are discussed together with those reported previously by our group mainly for LaFe1-yCoyAsO0.89F0.11 and LaFeAsO0.89-xF0.11+x systems. The y dependence of the electronic specific heat coefficient gamma can basically be understood by using the rigid-band picture, where Ni ions provide 2 electrons to the host conduction bands and behave as nonmagnetic impurities. The superconducting transition temperature Tc of LaFe1-yNiyAsO0.89F0.11 becomes zero, as the carrier density p (=2y+0.11) doped to LaFeAsO reaches its critical value p_c_ ~0.2. This p_c_ value of ~0.2 is commonly observed for LaFe1-yCoyAsO0.89F0.11 and LaFeAsO0.89-xF0.11+x systems, in which the relations p = x+0.11 and p = y+0.11 hold, respectively. As we pointed out previously, the critical value corresponds to the disappearance of the hole-Fermi surface. These results indicate that the carrier number solely determines the Tc value. We have not observed appreciable effects of pair breaking, which originates from the nonmagnetic impurity scattering of conduction electrons and strongly suppresses T_c_ values of systems with sign-reversing of the order parameter over the Fermi surface(s). On the basis of the results, the so-called s_+-_ symmetry of the order parameter with the sign-reversing is excluded.Comment: 4 pages, 7 figures, submitted to J. Phys. Soc. Jpn, (modified version

Sediment and Suspended Particulate Matter of Jakarta Bay, Indonesia

Jakarta Bay is a semi enclosed bay located in the northern coast of Jakarta Metropolitan City. Hydrologically 13 rivers flowing in the Jakarta region and there are three big rivers with significant discharge to the Jakarta Bay namely Citarum, Ciliwung, and Cisadane Rivers. Jakarta, as Indonesian capital city with population of 8.725.630 inhabitants, and another 15 million people live in the surrounded suburban of Jakarta, creates a significant anthropogenic impact to the environmental system. Limited infrastructures, such as no sewerage system and lack of industrial waste management, cause the rivers in this region have over their carrying capacity.Seventeen sampling stations were determined in the Jakarta Bay, consisting of 5 stations at the river mouths (estuaries) and other 12 stations in the bay spreading from the coastal to offshore areas. Water and sediment samples were taken during 2 monsoonal or seasonal variations, August 2006 for dry season and February 2007 for rainy season respectively. Additionally, samples were also taken in May 2007.Sediment distribution in the estuary consists mostly of black clay. The sediments clays were bad smell. In the coastal region and in the dry season, the sediments consists of black clay and at one sampling site (station S3) the sediment was bad smell. However, all sampling sites became bad smell in the rainy season. In the inner bay area, sediments were greyish green sandy clay with some shell fragments. In the outer bay, the sediments were dominated by greyish green clayey sand with some shell fragments. The black clay with bad smell is indicative of anthropogenic influence from Jakarta River Basin. C/N ratio of the sediments in the dry season ranged from 1 to about 4.2 where in the estuaries (at stations M1, M2 and M4) the ratio were higher compared to the inner and outer bays. The C/N ratio of suspended particulate matter ranged from the lowest ratio of 0.7 to the highest ratio of 17.7 at the bottom layer and lesser ranged of 0.7 to 9.8 at surface layer. POC concentrations ranged between 50-650 µM and 50-900 µM, in February and May, respectively. High concentrations of POC exists along the coastline or estuaries then decreasing toward the sea. POC is distributed widely in February than that in May due to higher discharge from the rivers. The average TOC concentrations in February is lower than that in May, but the TOC load in February was much higher than that in May due to the big differences of river discharge and because the samples were taken a week after the big flood in Jakarta area (February 4th - 6th, 2007). Total organic carbon fluxes from the river to the bay in February and May 2007 were 107.6 T /day C and 42.7 T /day C, respectively

Simple Real-Space Picture of Nodeless and Nodal s-wave Gap Functions in Iron Pnictide Superconductors

We propose a simple way to parameterize the gap function in iron pnictides. The key idea is to use orbital representation, not band representation, and to assume real-space short-range pairing. Our parameterization reproduces fairly well the structure of gap function obtained in microscopic calculation. At the same time the present parameterization is simple enough to obtain an intuitive picture and to develop a phenomenological theory. We also discuss simplification of the treatment of the superconducting state.Comment: 4 page