EOSDB: The Database for Nuclear EoS

Nuclear equation of state (EoS) plays an important role in understanding the formation of compact objects such as neutron stars and black holes. The true nature of the EoS has been a matter of debate at any density range not only in the nuclear physics but also in the astronomy and astrophysics. We have constructed a database of EoSs by compiling data from the literature. Our database contains the basic properties of the nuclear EoS of symmetric nuclear matter and of pure neutron matter. It also includes the detailed information about the theoretical models, for example the adopted methods and assumptions in individual models. The novelty of the database is to consider new experimental probes such as the symmetry energy, its slope relative to the baryon density, and the incompressibility, which enables the users to check their model dependences. We demonstrate the performance of the EOSDB through the examinations of the model dependence among different nuclear EoSs. It is reveled that some theoretical EoSs, which is commonly used in astrophysics, do not satisfactorily agree with the experimental constraints.Comment: 30 pages, 5 figures, submitted to Publications of the Astronomical Society of Japan (revised

On the best possible competitive ratio for the multislope ski-rental problem

The multislope ski-rental problem is an extension of the classical ski-rental problem, where the player has several lease options besides the pure rent and buy options. In this problem the hardness of an instance, which is the setting of options, significantly affects the player's performance. There is an algorithm that for a given instance, computes the best possible strategy. However, the output is given as numerical values and therefore the relational nature between an instance and the best possible performance for it has not been known. In this paper we prove that even for the easiest instance, a competitive ratio smaller than cannot be achieved. More precisely, a tight lower bound on the best possible performance is obtained in a closed form parametrized by the number of options. Furthermore, we establish a matching upper and lower bound on the competitive ratio each for the 3-option and 4-option problems.ArticleJOURNAL OF COMBINATORIAL OPTIMIZATION. 31(2): 463-490 (2016)journal articl

Chordotonal organs in hemipteran insects: unique peripheral structures but conserved central organization revealed by comparative neuroanatomy

Hemipteran insects use sophisticated vibrational communications by striking body appendages on the substrate or by oscillating the abdominal tymbal. There has been, however, little investigation of sensory channels for processing vibrational signals. Using sensory nerve stainings and low invasive confocal analyses, we demonstrate the comprehensive neuronal mapping of putative vibration-responsive chordotonal organs (COs) in stink bugs (Pentatomidae and Cydinidae) and cicadas (Cicadidae). The femoral CO (FCO) in stink bugs consists of ventral and dorsal scoloparia, homologous to distal and proximal scoloparia in locusts, which are implicated in joint movement detection and vibration detection, respectively. The ligament of the dorsal scoloparium is distally attached to the accessory extensor muscle, whereas that of the ventral scoloparium is attached to a specialized tendon. Their afferents project to the dorso-lateral neuropil and the central region of the medial ventral association center (mVAC) in the ipsilateral neuromere, where presumed dorsal scoloparium afferents and subgenual organ afferents are largely intermingled. In contrast, FCOs in cicadas have decreased dorsal scoloparium neurons and lack projections to the mVAC. The tymbal CO of stink bugs contains four sensory neurons that are distally attached to fat body cells via a ligament. Their axons project intersegmentally to the dorsal region of mVACs in all neuromeres. Together with comparisons of COs in different insect groups, the results suggest that hemipteran COs have undergone structural modification for achieving faster signaling of resonating peripheral tissues. The conserved projection patterns of COs suggest functional importance of the FCO and subgenual organ for vibrational communications

The relationships between AGN power and molecular gas mass within 500 pc of the center of elliptical galaxies

The physical quantity that directly controls the feedback of active galactic nuclei (AGNs) in galactic nuclei (AGN) in elliptical galaxies remains to be determined. The discovery of molecular gas around the AGNs suggests that the gas is fueling the AGNs. Therefore, we analyze Atacama Large Millimeter/submillimeter Array (ALMA) data on CO line (J=1-0, 2-1, 3-2) emission and estimate the mass of molecular gas within 500pc of the center of 12 normal elliptical galaxies and 10 of the brightest cluster galaxies (BCGs). We find that the mass (M_mol~10^5-10^9 M_sun) has a correlation with the jet power of their AGNs, which is represented by P_cav~6.2x10^42(M_mol/10^7M_sun)^{0.68} erg s^{-1}. We also find that M_mol is correlated with the AGN continuum luminosities at ~1.4GHz (L_{1.4}) and ~100-300GHz (L_con). Since P_cav reflects galactic-scale, long-term AGN activity, while the continuum luminosities reflect local (~<500pc), short-term AGN activity, our results suggest that the AGN activity depends on the amount of the gas, regardless of its time scale. On the other hand, we cannot find a clear correlation between the mass of the black holes in the AGNs (M_BH) and P_cav. While this is probably because the black holes in our sample galaxies have similar masses, it suggests that M_mol, rather than M_BH, is the main factor that controls the AGN activity. We confirm that the origin of the continuum emission from the AGNs at ~1.4-300GHz is mostly synchrotron radiation