Vacancy Size and Offered Wage: A Source of Search Friction in The Japanese Labor Market

Behind rising natural rate of unemployment, they often point out the decline in matching efficiency of the labor market. We empirically examine the cause of matching friction based on the theory of directed search model such as Burdett, Shi and Wright (2001). From rich micro data on vacancy size and wage variation of job changers in Japanese labor market, we observe the negative relationship between vacancy size and offered wage, which show the existence of search friction, not in the whole labor market but in some particular unskilled markets, especially those of clerks and production workers.Search friction, matching, directed search, vacancy, wage offer, Japan

Impact of domestic travel restrictions on transmission of COVID-19 infection using public transportation network approach

The international spread of COVID-19 infection has attracted global attention, but the impact of local or domestic travel restriction on public transportation network remains unclear. Passenger volume data for the domestic public transportation network in Japan and the time at which the first confirmed COVID-19 case was observed in each prefecture were extracted from public data sources. A survival approach in which a hazard was modeled as a function of the closeness centrality on the network was utilized to estimate the risk of importation of COVID-19 in each prefecture. A total of 46 prefectures with imported cases were identified. Hypothetical scenario analyses indicated that both strategies of locking down the metropolitan areas and restricting domestic airline travel would be equally effective in reducing the risk of importation of COVID-19. While caution is necessary that the data were limited to June 2020 when the pandemic was in its initial stage and that no other virus spreading routes have been considered, domestic travel restrictions were effective to prevent the spread of COVID-19 on public transportation network in Japan. Instead of lockdown that might seriously damage the economy, milder travel restrictions could have the similar impact on controlling the domestic transmission of COVID-19. © 2021, The Author(s)

電子レンジを利用して生成したプラズマの分光解析

A mechanical pencil lead or a dress pin absorbs electromagnetic waves emitted from a kitchen microwave as an antenna, both ends of which emit electrons. They ionize the surrounding gas molecules, and microwave-excited plasma is produced. The statistical properties (level statistics) of the energy-level spacing of spectroscopy of this plasma are discussed. It is known that different geometrical structures of the phase space in a classical system (for example, "islands" indicating periodicity and chaotic "seas") correspond to different statistical properties of energylevel spacing in a quantum system. The characteristics of level repulsions and attractions are reflected in a functional form of probability distribution functions of level spacing. From this viewpoint of quantum chaos, the energy spectra of the microwaveexcited plasma are considered.シャープペンの芯や待ち針は電子レンジのマイクロ波をよく吸収し, 加速された電子は両端から飛び出す. それは周囲の気体分子を電離させ, プラズマが生じる. このプラズマの分光解析を行う. 古典系の相空間の幾何学的構造(周期性を表す「島」やカオスの「海」)が対応する量子系のエネルギー準位の統計性に反映されることが知られているが, その観点を踏まえ, このプラズマの準位間隔の分布関数を求める

Effects of mesophyll water potential on photosynthesis in Cyperaceae plants: with special reference to phylogeny of tribes and decarboxylation sub-types

We examined the photosynthetic rates under water stress conditions in 43 Japanese Cyperaceae species using the same method used for Gramineae plants. Compared with Gramineae, the difference between C4 and C3 species was more distinct in Cyperaceae. Moreover, C4 Cyperaceae species were very susceptible to water stress like Panicoideae C4 species. These species belong to the NADP-ME subtype. It appears that the sensitivity of photosynthesis to water stress would be different depending on the decarboxylation sub-types

Ultrafast melting of charge-density wave fluctuations at room temperature in 1T−TiSe2{1T-TiSe_2} monitored under non-equilibrium conditions

We investigate the ultrafast lattice dynamics in ${1T-TiSe_2}$ using femtosecond reflection pump-probe and pump-pump-probe techniques at room temperature. The time-domain signals and Fourier-transformed spectra show the $A_{1g}$ phonon mode at 5.9 THz. Moreover, we observe an additional mode at $\approx$ 3 THz, corresponding to the charge-density wave (CDW) amplitude mode, which is generally visible below T$_c \approx 200\$K. We argue that the emergence of the CDW amplitude mode at room temperature can be a consequence of fluctuations of order parameters, based on the additional experiment using the pump-pump-probe technique, which exhibited suppression of the AM signal within the ultrafast time scale of $\sim$ 0.5 ps.Comment: 15 pages, 3 figures, Applied Physics Letters, in pres

Single-molecule fluorescence polarization study of conformational change in archaeal group II chaperonin.

Group II chaperonins found in archaea and in eukaryotic cytosol mediate protein folding without a GroES-like cofactor. The function of the cofactor is substituted by the helical protrusion at the tip of the apical domain, which forms a built-in lid on the central cavity. Although many studies on the change in lid conformation coupled to the binding and hydrolysis of nucleotides have been conducted, the molecular mechanism of lid closure remains poorly understood. Here, we performed a single-molecule polarization modulation to probe the rotation of the helical protrusion of a chaperonin from a hyperthermophilic archaeum, Thermococcus sp. strain KS-1. We detected approximately 35° rotation of the helical protrusion immediately after photorelease of ATP. The result suggests that the conformational change from the open lid to the closed lid state is responsible for the approximately 35° rotation of the helical protrusion

Gas Exchange Rates Decrease and Leaf Temperature Increases in Nicotiana benthamiana Leaves Transiently Overexpressing Hemagglutinin in an Agrobacterium-Assisted Viral Vector System

In this study, gas exchange characteristics and temperature of Nicotiana benthamiana leaves transiently overexpressing hemagglutinin (HA), an influenza vaccine antigen, with an Agrobacterium tumefaciens-assisted viral vector were investigated. Inoculation of leaves with an empty viral vector not containing the HA gene decreased the net photosynthetic rate (Pn) and transpiration rate (T) from 2 to 3 days post-infiltration (DPI) in the A. tumefaciens suspension. Expression of HA with the vector decreased Pn and T to much lower levels until 4 DPI. Such significant decreases were not observed in leaves infiltrated with suspension of A. tumefaciens not carrying the viral vector or in uninfiltrated leaves. Thus, viral vector inoculation itself decreased Pn and T to a certain extent and the HA expression further decreased them. The decreases in Pn and T in empty vector-inoculated and HA expression vector-inoculated leaves were associated with decreases in stomatal conductance, suggesting that the reduction of gas exchange rates was caused at least in part by stomatal closure. More detailed gas exchange and chlorophyll fluorescence analyses revealed that in HA vector-inoculated leaves, the capacity of ribulose-1,5-bisphosphate carboxylase/oxygenase to assimilate CO2 and the capacity of photosynthetic electron transport in planta were downregulated, which contributed also to the decrease in Pn. Leaf temperature (LT) increased in viral vector-inoculated leaves, which was associated with the decrease in T. When HA vector-inoculated leaves were grown at air temperatures (ATs) of 21, 23, and 26°C post-infiltration, HA accumulated earlier in leaves and the days required for HA content to attain its peak became shorter, as AT was higher. The highest LT was found 1–2 days earlier than the highest leaf HA content under all post-infiltration AT conditions. This phenomenon could be applicable in a non-destructive technique to detect the optimum harvesting date for individual plants to determine the day when leaf HA content reaches its maximum level, irrespective of spatiotemporal variation of AT, in a plant growth facility

Environmentally Benign Ritter Reaction Using Bismuth Salts as a Catalyst

We developed an environmentally benign Ritter reaction of alcohols with nitriles using a commercially available bismuth salt as a less harmful catalyst. The detailed reaction profiles revealed that consumption of the ether by-product as the reaction proceeded was the key for optimizing this reaction, and the yield of the target amide was improved by adding a small amount of water. This finding clearly reveals the significance of using a bismuth salt as the catalyst, as it is not deactivated in the presence of water. This catalyst system has a broad substrate scope, and even with 1 mol% of the catalyst, the reaction progresses smoothly. It is also possible to react stoichiometric amounts of nitriles and alcohols, thus reducing the amount of organic solvent required for the reaction. Furthermore, as the inexpensive bismuth catalyst can be easily removed using aqueous hydrochloric acid, a purification process that only required washing and drying without any organic solvents was successfully established

Fine Structures of Shock of SN 1006 with the Chandra Observation

The north east shell of SN 1006 is the most probable acceleration site of high energy electrons (up to ~ 100 TeV) with the Fermi acceleration mechanism at the shock front. We resolved non-thermal filaments from thermal emission in the shell with the excellent spatial resolution of Chandra. The thermal component is extended widely over about ~ 100 arcsec (about 1 pc at 1.8 kpc distance) in width, consistent with the shock width derived from the Sedov solution. The spectrum is fitted with a thin thermal plasma of kT = 0.24 keV in non-equilibrium ionization (NEI), typical for a young SNR. The non-thermal filaments are likely thin sheets with the scale widths of ~ 4 arcsec (0.04 pc) and ~ 20 arcsec (0.2 pc) at upstream and downstream, respectively. The spectra of the filaments are fitted with a power-law function of index 2.1--2.3, with no significant variation from position to position. In a standard diffusive shock acceleration (DSA) model, the extremely small scale length in upstream requires the magnetic field nearly perpendicular to the shock normal. The injection efficiency (eta) from thermal to non-thermal electrons around the shock front is estimated to be ~ 1e-3 under the assumption that the magnetic field in upstream is 10 micro G. In the filaments, the energy densities of the magnetic field and non-thermal electrons are similar to each other, and both are slightly smaller than that of thermal electrons. in the same order for each other. These results suggest that the acceleration occur in more compact region with larger efficiency than previous studies.Comment: 24 pages, 11 figures, Accepted for publication in ApJ, the paper with full resolution images in http://www-cr.scphys.kyoto-u.ac.jp/member/bamba/Paper/SN1006.pd