Endogenous rhythm variation and adaptation to the tidal environment in the freshwater snail, Semisulcospira reiniana

Organisms have endogenous timekeeping system(s) to coordinate their biological processes with environmental cycles, allowing adaptation to external rhythmic changes in their environment. The change in endogenous rhythms could contribute to range expansion in a novel rhythmic environment. We hypothesized that populations of the freshwater snail near estuaries show a circatidal rhythm to synchronize with the tidal cycle. We compared the behavioral and gene expression rhythms between non-tidal and tidal populations of the freshwater snail, Semisulcospira reiniana. Individuals inhabiting tidal areas exhibited a rhythmic activity pattern coordinated with the tidal cycle under both field and laboratory conditions, but individuals inhabiting upstream non-tidal areas showed a circadian activity pattern. The proportion of circadian oscillating genes was greater in non-tidal than in tidal individuals, while that of circatidal oscillating genes was greater in tidal than in non-tidal individuals. Additionally, transcriptome-wide population genetic analyses revealed that these two adjacent populations can be clearly distinguished genetically, though the genetic distance was very small. Our results provide evidence of the shift in an endogenous rhythm via range expansion to a novel rhythmic environment. The changes in a small number of genes and/or phenotypic plasticity may contribute to the difference in the endogenous rhythms between non-tidal and tidal populations

Sexual selection on wing interference patterns in Drosophila melanogaster

Animals with color vision use color information in intra- and interspecific communication, which in turn may drive the evolution of conspicuous colored body traits via natural and sexual selection. A recent study found that the transparent wings of small flies and wasps in lower-reflectance light environments display vivid and stable structural color patterns, called “wing interference patterns” (WIPs). Such WIPs were hypothesized to function in sexual selection among small insects with wing displays, but this has not been experimentally verified. Here, to our knowledge we present the first experimental evidence that WIPs in males of Drosophila melanogaster are targets of mate choice from females, and that two different color traits—saturation and hue—experience directional and stabilizing sexual selection, respectively. Using isogenic lines from the D. melanogaster Genetic Reference Panel, we compare attractiveness of different male WIPs against black and white visual backgrounds. We show that males with more vivid wings are more attractive to females than are males with dull wings. Wings with a large magenta area (i.e., intermediate trait values) were also preferred over those with a large blue or yellow area. These experimental results add a visual element to the Drosophila mating array, integrating sexual selection with elements of genetics and evo-devo, potentially applicable to a wide array of small insects with hyaline wings. Our results further underscore that the mode of sexual selection on such visual signals can differ profoundly between different color components, in this case hue and saturation

High-resolution spectroscopy and single-photon Rydberg excitation of reconfigurable ytterbium atom tweezer arrays utilizing a metastable state

We present an experimental system for Rydberg tweezer arrays with ytterbium (Yb) atoms featuring internal state manipulation between the ground ${}^1$S$_0$ and the metastable ${}^3$P$_2$ states, and single-photon excitation from the ${}^3$P$_2$ to Rydberg states. In the experiments, single Yb atoms are trapped in two-dimensional arrays of optical tweezers and are detected by fluorescence imaging with the intercombination ${}^1$S$_0 \leftrightarrow {}^3$P$_1$ transition, and the defect-free single atom arrays are prepared by the rearrangement with the feedaback. We successfully perform high-resolution ${}^1$S$_0\leftrightarrow {}^3$P$_2$ state spectroscopy for the single atoms, demonstrating the utilities of this ultranarrow transition. We further perform single-photon excitation from the ${}^3$P$_2$ to Rydberg states for the single atoms, which is a key for the efficient Rydberg excitation. We also perform a systematic measurement of a complex energy structure of a series of D states including newly observed ${}^3$D$_3$ states. The developed system shows feasibility of future experiments towards quantum simulations and computations using single Yb atoms.Comment: 10 pages, 9 figure

The carbonization of aromatic molecules with three-dimensional structures affords carbon materials with controlled pore sizes at the Ångstrom-level

分子構造により細孔径を制御したカーボンを開発. 京都大学プレスリリース. 2021-05-24.Carbon materials with controlled pore sizes at the nanometer level have been obtained by template methods, chemical vapor desorption, and extraction of metals from carbides. However, to produce porous carbons with controlled pore sizes at the Ångstrom-level, syntheses that are simple, versatile, and reproducible are desired. Here, we report a synthetic method to prepare porous carbon materials with pore sizes that can be precisely controlled at the Ångstrom-level. Heating first induces thermal polymerization of selected three-dimensional aromatic molecules as the carbon sources, further heating results in extremely high carbonization yields (>86%). The porous carbon obtained from a tetrabiphenylmethane structure has a larger pore size (4.40 Å) than those from a spirobifluorene (4.07 Å) or a tetraphenylmethane precursor (4.05 Å). The porous carbon obtained from tetraphenylmethane is applied as an anode material for sodium-ion battery

南極ドロンイング・モードランドアイスコアの酸素同位体比周期解析とピーク周期の有意性

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　国立極地研究所１階交流アトリウ

Can Insurance Payouts Prevent a Poverty Trap? Evidence from Randomized Experiments in Northern Kenya

Index-based insurance can have welfare-enhancing effects through two pathways: by mitigating weather-related shocks through payouts and by inducing policyholders to take greater yet more profitable risks. Most studies fail to distinguish between these two. Thus, we know little about which effects dominate and their long-term welfare implications. Using a random distribution of discount coupons and drought events that trigger payouts as exogenous variations, this study aims to identify both the ex ante risk-management and ex post payout effects of index insurance in a pastoral-dominant society of northern Kenya, where the presence of asset-based poverty traps, represented by bifurcated herd-size dynamics, has been established in the literature. We find the following: (1) Both risk-management and payout effects contribute to reducing the probability of distress sales of livestock; (2) payout effects also lead to a reduced slaughter of livestock; (3) while payout effects remain robust in a subsample of poorer households below the poverty trap threshold, risk-management effects do not. Overall, our results suggest that insurance payouts assist people in escaping from poverty traps more effectively than do behavioural changes accompanied by insurance purchases.JEL Classification Codes: O12, I32, G22, Q1

Understanding Pastoralists’ Dynamic Insurance Uptake Decisions: Evidence from Four-year Panel Data in Ethiopia

Using a unique data set covering four years and six semi-annual sales periods of an index-based livestock insurance (IBLI) product in southern Ethiopia, we examine the dynamics of pastoralists’ demand for IBLI. We find that: (1) there is intertemporal dependence of an uptake decision, represented by correlations of unobserved household factors over time; (2) conditional on previous purchase decisions, factors related to continuing the purchase of IBLI to augment existing coverage and replace lapsing contracts differ significantly; (3) controlling for time-invariant household-fixed effects, neither a one-shot subsidy nor the uptake of others in one’s social network influence subsequent demand, whereas less vegetation and reduced insurance premiums induce households to purchase IBLI. Overall, our study provides rigorous micro-evidence to better understand the dynamic uptake of IBLI and signifies the importance of an empirical analysis that takes into account the dynamic demand structure.JEL Classification Codes: D12, D14, D81, G22, O12This work was made possible by the financial support provided by Cornell University, National Graduate Institute for Policy Studies (GRIPS), the International Livestock Research Institute (ILRI), the JSPS Grant-in-Aid for Scientific Research (B)-26301021, the US Agency for International Development (USAID) Agreement No. LAG-A-00-96-90016-00 through the Broadening Access and Strengthening Input Market Systems Collaborative Research Support Program (BASIS AM) Innovation Lab, the Department of Foreign Affairs and Trade through the Australia Development Research Awards Scheme, and the CGIAR Research Programs on Climate Change, Agriculture and Food Security, and on Dryland Systems.https://www.grips.ac.jp/list/jp/facultyinfo/takahashi-kazushi

Initial Results from the Nobeyama Molecular Gas Observations of Distant Bright Galaxies

We present initial results from the CO survey toward high redshift galaxies using the Nobeyama 45m telescope. Using the new wide bandwidth spectrometer equipped with a two-beam SIS receiver, we have robust new detections of three high redshift (z=1.6-3.4) submillimeter galaxies (SXDF 1100.001, SDP9, and SDP17), one tentative detection (SDSS J160705+533558), and one non-detection (COSMOS-AzTEC1). The galaxies observed during the commissioning phase are sources with known spectroscopic redshifts from previous optical or from wide-band submm spectroscopy. The derived molecular gas mass and line widths from Gaussian fits are ~10^11 Msun and 430-530 km/s, which are consistent with previous CO observations of distant submm galaxies and quasars. The spectrometer that allows a maximum of 32 GHz instantaneous bandwidth will provide new science capabilities at the Nobeyama 45m telescope, allowing us to determine redshifts of bright submm selected galaxies without any prior redshift information.Comment: 4 pages, 1 figure, PASJ Letter Accepte