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For a closed, connected, and oriented 3-manifold with a non-singular flow, we construct its virtual knot diagram via a “flow-spine” of the manifold. Then, we introduce a coloring invariant of 3-manifolds through their virtual knot diagrams, and classify some 3-manifolds by using the invariant.

JGR / Atmospheres 128(11), e2022JD038249 (2023). doi:10.1029/2022JD038249, An international joint research project, entitled Interhemispheric Coupling Study by Observations and Modelling (ICSOM), is ongoing. In the late 2000s, an interesting form of interhemispheric coupling (IHC) was discovered: when warming occurs in the winter polar stratosphere, the upper mesosphere in the summer hemisphere also becomes warmer with a time lag of days. This IHC phenomenon is considered to be a coupling through processes in the middle atmosphere (i.e., stratosphere, mesosphere, and lower thermosphere). Several plausible mechanisms have been proposed so far, but they are still controversial. This is mainly because of the difficulty in observing and simulating gravity waves (GWs) at small scales, despite the important role they are known to play in middle atmosphere dynamics. In this project, by networking sparsely but globally distributed radars, mesospheric GWs have been simultaneously observed in seven boreal winters since 2015/16. We have succeeded in capturing five stratospheric sudden warming events and two polar vortex intensification events. This project also includes the development of a new data assimilation system to generate long-term reanalysis data for the whole middle atmosphere, and simulations by a state-of-the-art GW-permitting general circulation model using the reanalysis data as initial values. By analyzing data from these observations, data assimilation, and model simulation, comprehensive studies to investigate the mechanism of IHC are planned. This paper provides an overview of ICSOM, but even initial results suggest that not only GWs but also large-scale waves are important for the mechanism of the IHC., Published by Wiley, Hoboken, NJ

The 13th Symposium on Polar Science/Interdisciplinary sessions [IW] Whole atmosphere, Fri. 18 Nov.

The 13th Symposium on Polar Science/Interdisciplinary sessions [IW] Whole atmosphere, Fri. 18 Nov.

The 13th Symposium on Polar Science/Interdisciplinary sessions [IW] Whole atmosphere, Fri. 18 Nov.

The 13th Symposium on Polar Science/Ordinary sessions [OS] Space and upper atmospheric sciences, Wed. 16 Nov.

The 13th Symposium on Polar Science/Special session [S] Towards the next six-year Japanese Antarctic Research Project (phase X), Tue. 15 Nov.

The 13th Symposium on Polar Science/Special session [S] Towards the next six-year Japanese Antarctic Research Project (phase X), Tue. 15 Nov.

Estimating arbuscular mycorrhizal (AM) fungal activity to colonize crop root before cultivation is prerequisite for effective utilization of their functions which enhance growth and yield of the plant especially under low fertilizer input. We have hypothesized that the infection unit (IU) density formed on test plant roots grown for short period (12 days) with soil sampled from soybean production fields would be an effective indicator to predict AM fungal colonization intensity to the plant. In order to test this hypothesis, three-year farmland survey was conducted, in which soil samples before sowing soybean and the plant root samples at third trifoliate (V3) and full bloom (R2) stage were collected from farmers’ fields in two regions in Hokkaido, Iwamizawa and Tokachi. For each sampling spot, IU density was determined by using test plants, and intensity of AM fungal colonization of soybean root was measured. Before pursuing field survey, laboratory experiments were conducted to find out proper soil storage condition that keeps IU density unchanged while handling many soil samples. Our results indicated that IU density was almost comparable to the original value after six-month storage if soil samples were kept in a refrigerator, although storing at ambient temperature significantly decreased the measurement. Air drying also had negative impact on IU density. According to the field survey, IU densities determined using field soil were positively and significantly correlated with AM fungal colonization of soybean roots at both V3 and R2 stages. Differences in climate, soil type, and style of agriculture between Iwamizawa and Tokachi seemed to have little effect on IU density-AM fungal colonization relationship. Other than IU density, soil pH and soil penetration resistance at 10 cm depth were selected as significant explanatory variables for predicting AM fungal colonization by multiple regression analysis. However, IU density was the most influential factor among three. Therefore, IU density is recognized as an effective measure to evaluate AM fungal colonizing activity in field soil.

Made available in DSpace on 2022-04-12T19:01:10Z (GMT). No. of bitstreams: 1 C-MIRANDA-SEG-semm-vinculacao-Nakamura-et-al.-2022-.pdf: 3193374 bytes, checksum: 7367779a5f04606246e3164dc46b8991 (MD5) Previous issue date: 2022 Na publicação - Cesar Miranda (National Beef Cattle Research Center, Brazilian Agricultural Research Corporation, Mato Grosso do Sul State, Brazil).