41 research outputs found
Local Hurst Exponent Computation of Data from Triaxial Seismometers Monitoring KAGRA
No full textThe Hurst exponent was computed locally for three triaxial seismometers monitoring the KAGRA corner station and the two end stations of the interferometer allowing to estimate variability in the persistent behaviour of the seismometer time series. Results show that, in all the three cases considered, the vertical component of the seismometer has lower persistency compared to the horizontal degrees of freedom, as also confirmed by the low frequency region of the amplitude spectral density of the data. Furthermore, data of the horizontal components of the EXV end station, located in the direction of the X arm of the interferometer, exhibits lower values of seismic noise and of its Hurst exponent. This is possibly due to the lack of an exit point at this location, and hence to a reduced human activity, to the presence of water flow in the mine hosting the KAGRA detector or to differences in seismometers' self noise
Status of R&D of the ANKOK project: Low mass WIMP search using double phase argon detector
No full text
Geometric Monodromy around the Tropical Limit
No full textLet {Vq}q be a complex one-parameter family of smooth hypersurfaces in a toric variety. In this paper, we give a concrete description of the monodromy transformation of {Vq}q around q=∞ in terms of tropical geometry. The main tool is the tropical localization introduced by Mikhalkin.The author would like to express his gratitude to Kazushi Ueda for encouragement and helpful
advices. The author thanks to Tatsuki Kuwagaki for explaining the context of the paper [2].
The author also thanks the anonymous referees for reading this paper carefully and giving many
helpful comments. This research is supported by the Program for Leading Graduate Schools,
MEXT, Japan
The Current Status and Future Prospects of KAGRA, the Large-Scale Cryogenic Gravitational Wave Telescope Built in the Kamioka Underground
No full textKAGRA is a gravitational-wave (GW) detector constructed in Japan with two unique key features: It was constructed underground, and the test-mass mirrors are cooled to cryogenic temperatures. These features are not included in other kilometer-scale detectors but will be adopted in future detectors such as the Einstein Telescope. KAGRA performed its first joint observation run with GEO600 in 2020. In this observation, the sensitivity of KAGRA to GWs was inferior to that of other kilometer-scale detectors such as LIGO and Virgo. However, further upgrades to the detector are ongoing to reach the sensitivity for detecting GWs in the next observation run, which is scheduled for 2022. In this article, the current situation, sensitivity, and future perspectives are reviewed
The hunt for environmental noise in Virgo during the third observing run
No full textAbstract: The first twenty years of operation of gravitational-wave interferometers have shown that these detectors are affected by physical disturbances from the surrounding environment. These are seismic, acoustic, or electromagnetic disturbances that are mainly produced by the experiment infrastructure itself. Ambient noise can limit the interferometer sensitivity or potentially generate transients of non-astrophysical origin. Between 1 April 2019 and 27 March 2020, the network of second generation interferometers-LIGO, Virgo and GEO-performed the third joined observing run, named O3, searching for gravitational signals from the deep universe. A thorough investigation has been done on each detector before and during data taking in order to optimize its sensitivity and duty cycle. In this paper, we first revisit typical sources of environmental noise and their coupling paths, and we then describe investigation methods and tools. Finally, we illustrate applications of these methods in the hunt for environmental noise at the Virgo interferometer during the O3 run and its preparation phase. In particular, we highlight investigation techniques that might be useful for the next observing runs and the future generation of terrestrial interferometers
Is the copulation of silver-washed fritillary inverted? Function of the female genital projection (Lepidoptera: Nymphalidae: Argynnini)
No full textFemales of the silver-washed fritillary butterfly, Argynnis paphia (Linnaeus), and its relatives are known to have a unique genital projection called the cornucopia. Previous observations showed that the cornucopia partly penetrates the male genitalia during copulation, but its detailed structures and functions are unknown to date. Our observations using light microscopy, confocal laser scanning microscopy, scanning electron microscopy, and microcomputed tomography suggested that penetration by the female cornucopia occurs passively, and it is hooked and pulled by the male towards the male genitalia using sharp teeth on the uncus. This hooking and pulling causes wounds on the dorsal region of the cornucopia. Artificial amputation of a cornucopia confirmed that it is indispensable for spermatophore transfer from males and functions to break off the male phallic spines (cornuti). The broken spines may be used by females to help the digestion of spermatophores in the female's corpus bursae. Females with larger body sizes had more broken spines in the corpus bursae, indicating that secure holding of a large female during copulation is challenging for males
Traumatic copulation and counterpart female traits are widespread in fritillary butterflies (Lepidoptera: Nymphalidae : Argynnini)
No full textFemale fritillary butterflies (Lepidoptera: Nymphalidae: Argynnini) are known to have diversified genital structures, especially at the entrance of the bursa copulatrix. However, the origin and function of such elaborated structures are poorly known to date. We examined the male and female genital structures of six Japanese species selected from five genera/subgenera [Argynnis (Argynnis), Argynnis (Damora), Argynnis (Argyronome), Fabriciana, and Speyeria] of the Argynnini tribe and found that traumatic copulation is widespread in Argynnini. Various male genital structures, such as the uncus, valva, and phallus, can cause wounds to the female genitalia. The eighth venter of the female, where the highest morphological diversity in female genitalia was detected, is hooked and held by the male uncus during copulation. It is very likely that the diversified female genital structure coevolved with the male uncus as a counterpart for traumatic coupling. Female fritillary butterflies (Lepidoptera: Nymphalidae: Argynnini) are known to have diversified genital structures. We found that the traumatic copulation is widespread in Argynnini. It is very likely that the highly diversified female genital structure coevolved with the male uncus as a counterpart trait. imag
スケトウダラ着底トロール調査におけるワープ長の違いが網形状と漁獲に与える影響
No full textWe examined variation in trawl dimension, bottom contact, and catch with differing warp lengths during walleye pollock surveys conducted by the Fisheries Research Agency. The ratio of warp length to fishing depth (scope ratio) was set at 2.5, 3.0 and 3.5 at depths of 110 m. At a 2.5 scope ratio, the net mouth shape and footgear contact fluctuated, as the trawl door did not contact the bottom. Footgear contact was complete when the scope ratio was 3.0 or more. Walleye pollock, sculpins, and flatfishes were the main catch in all tows, and the catch increased with scope ratio. There was no difference in the length frequency of n= 300 walleye pollock captured at 2.5 and 3.0 scope ratio. However, the length frequency at 3.5 was significantly different from that of other scope ratios. These results suggest the following: at a scope ratio of 3.0 or more, the trawl door will not leave the bottom at any depths. To compliment echo surveys for walleye pollock, a 3.0 scope ratio would be optimal, since the catch data for a 3.5 scope ratio was dissimilar from that of scope ratios
