In this paper, a curve is any projective scheme of pure dimension one. It is well known that the arithmetic genus and the degree of an aCM curve
D
in
P
3
are computed by the
h
-vector of
D
. However, ...for a given curve
D
in
P
3
, the two aforementioned invariants of
D
do not tell us whether
D
is aCM or not. If
D
is an aCM curve on a smooth surface
X
in
P
3
, any member of the linear system
|
D
+
l
C
|
is also aCM for each non-negative integer
l
, where
C
is a hyperplane section of
X
. By a previous work, if a non-zero effective divisor
D
of degree
d
and arithmetic genus
g
on a smooth quintic surface
X
in
P
3
is aCM and satisfies the condition
h
0
(
O
X
(
D
-
C
)
)
=
0
, then
0
≤
d
+
1
-
g
≤
4
. In this paper, we classify non-aCM effective divisors on smooth quintic surfaces in
P
3
of degree
d
and arithmetic genus
g
such that
0
≤
d
+
1
-
g
≤
4
, and give several examples of them.
Let
X
be a smooth quartic hypersurface in
P
3
. By the Brill-Noether theory of curves on K3 surfaces, if a rank 2 aCM bundle on
X
is globally generated, then it is the Lazarsfeld-Mukai bundle
E
C
,
Z
...associated with a smooth curve
C
on
X
and a base point free pencil
Z
on
C
. In this paper, we will focus on the classification of such bundles on
X
to investigate aCM bundles of rank 2 on
X
. Concretely, we will give a necessary condition for a rank 2 vector bundle of type
E
C
,
Z
to be indecomposable initialized and aCM, in the case where the class of
C
in
Pic
(
X
)
is contained in the sublattice of rank 2 generated by the hyperplane class of
X
and a non-trivial initialized aCM line bundle on
X
.
Let
φ
:
Σ
1
⟶
P
2
be a blow up at a point on
P
2
. Let
C
be the proper transform of a smooth plane curve of degree
d
≥
4
by
φ
, and let
P
be a point on
C
. Let
π
:
C
~
⟶
C
be a double covering ...branched along the reduced divisor on
C
obtained as the intersection of
C
and a reduced divisor in
|
-
2
K
Σ
1
|
containing
P
. In this paper, we investigate the Weierstrass semigroup
H
(
P
~
)
at the ramification point
P
~
of
π
over
P
, in the case where the intersection multiplicity at
φ
(
P
)
of
φ
(
C
)
and the tangent line at
φ
(
P
)
of
φ
(
C
)
is
d
-
1
.
Carbon captured by marine organisms helps sequester atmospheric CO2, especially in shallow coastal ecosystems, where rates of primary production and burial of organic carbon (OC) from multiple ...sources are high. However, linkages between the dynamics of OC derived from multiple sources and carbon sequestration are poorly understood. We investigated the origin (terrestrial, phytobenthos derived, and phytoplankton derived) of particulate OC (POC) and dissolved OC (DOC) in the water column and sedimentary OC using elemental, isotopic, and optical signatures in Furen Lagoon, Japan. Based on these data analysis, we explored how OC from multiple sources contributes to sequestration via storage in sediments, water column sequestration, and air–sea CO2 exchanges, and analyzed how the contributions vary with salinity in a shallow seagrass meadow as well. The relative contribution of terrestrial POC in the water column decreased with increasing salinity, whereas autochthonous POC increased in the salinity range 10–30. Phytoplankton‐derived POC dominated the water column POC (65–95%) within this salinity range; however, it was minor in the sediments (3–29%). In contrast, terrestrial and phytobenthos‐derived POC were relatively minor contributors in the water column but were major contributors in the sediments (49–78% and 19–36%, respectively), indicating that terrestrial and phytobenthos‐derived POC were selectively stored in the sediments. Autochthonous DOC, part of which can contribute to long‐term carbon sequestration in the water column, accounted for >25% of the total water column DOC pool in the salinity range 15–30. Autochthonous OC production decreased the concentration of dissolved inorganic carbon in the water column and thereby contributed to atmospheric CO2 uptake, except in the low‐salinity zone. Our results indicate that shallow coastal ecosystems function not only as transition zones between land and ocean but also as carbon sequestration filters. They function at different timescales, depending on the salinity, and OC sources.
In the previous works, we gave a necessary condition for Lazarsfeld–Mukai bundles of rank 2 on a K3 surface X to be given by an extension of two line bundles, under a numerical condition (10, Theorem ...3.1). Moreover, we have classified line bundles which appear in such an extension, in the case where X is a smooth quartic hypersurface in P3 (10, Proposition 3.1) as a corollary of it. However, the assertion of it contains a few mistakes. In this paper, we correct them, and give an application of the results in 10.
Let
X
be a
K
3 surface and let
H
be a very ample line bundle on
X
of sectional genus
g
≤ 9. In this paper, we characterize the destabilizing sheaf of the Lazarsfeld-Mukai bundle
E
C
,
Z
of rank 2 ...associated with a smooth curve
C
∈ |
H
| and a base point free divisor
Z
on
C
with
h
0
(
O
C
(
Z
)) = 2, in the case where it is not
H
-slope stable.
Let
X
be a smooth quintic hypersurface in
P
3
, let
C
be a smooth hyperplane section of
X
, and let
H
=
O
X
(
C
)
. In this paper, we give a necessary and sufficient condition for the line bundle ...given by a non-zero effective divisor on
X
to be initialized and aCM with respect to
H
.
Human interventions have had unintended consequences for the diverse functions of various ecosystems. Hydrological interventions have the potential to alter vegetated habitats in coastal nearshore ...ecosystems, but little is known about the impacts on organic carbon (Corg) sequestration, which plays an important role in climate change mitigation.
We examined the effects of past human interventions through artificial inlet opening in a lagoonal seagrass meadow. The sediment profiles of geological and biogeochemical characteristics were measured to obtain the historical changes in the lagoon environment and Corg accumulation rates.
Isotopic and elemental signatures and diatom assemblages showed that the interventions increased the duration of seawater exchanges and the extent of the seagrass meadow. Corg accumulation rates increased more than 1.9‐fold after the intervention, resulting in additional Corg storage in the seagrass meadow during last 64 years.
Synthesis and applications. Artificial opening of tidal inlet can potentially provide unintended ecological benefits, such as increased carbon sequestration in seagrass meadows. Hydrological interventions could be undertaken intentionally as a potential active intervention to sequester carbon, as well as control flood risk and provide other benefits to people in estuarine systems. Our results illustrate that physical factors such as improving salinity conditions and mineral particle supply have an impact on the feasibility of hydrological interventions for enhancing carbon sequestration. We propose that biogeochemical–physical coupled approach will help stakeholders to evaluate the ecological and social risks and synergies of implementing hydrological interventions.
概要
人間による自然への介入は多様な生態系機能に対して意図しない結果をもたらしてきた。治水や利水を目的とした水理的介入 (海岸工事等の環境改変) は沿岸植生域の環境を変化させる可能性がある。藻場や塩性湿地といったブルーカーボン生態系が有する炭素隔離機能は気候変動の緩和のために重要な役割を担っているが、この生態系機能に対する水理的介入の影響はほとんど分かっていない。
本研究では、ラグーンに発達した海草藻場 (アマモ場) において、湖口開削という過去の水理的介入の影響を調査した。堆積物コアを採取し、堆積年代測定と生物地球化学的分析を組み合わせることで、ラグーンの環境と有機炭素貯留速度の過去から現在までの変化を調べた。
炭素安定同位体比、元素比及び珪藻群集の結果から、過去の湖口開削によって海水交換が促進され、海草藻場が拡大したことが示された。湖口開削が行われて以降、有機炭素貯留速度は1.9倍以上増加し、水理的介入が行われてから現在までの64年間で海草藻場内に追加的にブルーカーボンが貯留されていたことが明らかとなった。
まとめと応用: 人工的な湖口開削は、海草藻場における炭素隔離を強化するなどの意図しない利益を人間にもたらす可能性がある。水理的介入は治水や利水を目的とするのはもちろんのこと、炭素隔離を促進させうる潜在的な人為介入であり、この他にも様々なコベネフィットをもたらす可能性がある。本研究の結果は、塩分環境の改善や鉱物粒子の供給といった物理的要因が水理的介入による炭素隔離強化の成否を左右することを示した。したがって、水理的介入の実行による生態学的及び社会学的リスクとシナジーをステークホルダーが正しく評価する際には、生物学的な側面だけでなく、物理学的な側面も考慮した統合的なアプローチが有効である。
Artificial opening of tidal inlet can potentially provide unintended ecological benefits, such as increased carbon sequestration in seagrass meadows. Hydrological interventions could be undertaken intentionally as a potential active intervention to sequester carbon, as well as control flood risk and provide other benefits to people in estuarine systems. Our results illustrate that physical factors such as improving salinity conditions and mineral particle supply have an impact on the feasibility of hydrological interventions for enhancing carbon sequestration. We propose that biogeochemical–physical coupled approach will help stakeholders to evaluate the ecological and social risks and synergies of implementing hydrological interventions.
Previous studies have shown that antibiotic use and enterocolitis increase the risk of developing inflammatory bowel disease (IBD) in western countries. However, these risk factors have not yet been ...identified in Asian populations. This study aimed to investigate the risk of IBD development associated with antibiotic use and enterocolitis in Japan. A Japanese health insurance claims database was used to identify patients recently diagnosed with Crohn's disease (CD) and ulcerative colitis (UC) along with five matched participants without IBD. Episodes of antibiotic use and enterocolitis for 1 and 2 years before the date of diagnosis were analyzed using a conditional regression test. A total of 371 patients with CD and 2420 with UC were included. The adjusted odds ratio (AOR) increased in association with antibiotic use to 1.61 (95% confidence interval CI 1.26-2.05) and 1.20 (95% CI 1.09-1.31) and enterocolitis to 3.40 (95% CI 2.60-4.44) and 2.14 (95% CI 1.88-2.43) in 1 year in CD and UC, respectively. The risk associated with antibiotics was independent of the number or type of antibiotics, and the risk associated with enterocolitis did not differ with the pathogen that caused the disease. However, prior exposure to antibiotic use and enterocolitis was associated with an increased risk of developing IBD.
Improvement of water splitting performance of AgTaO3 (BG 3.4 eV) of a valence-band-controlled photocatalyst was examined. Survey of cocatalysts revealed that a Rh0.5Cr1.5O3 cocatalyst was much more ...effective than Cr2O3, RuO2, NiO and Pt for water splitting into H2 and O2 in a stoichiometric amount. The optimum loading amount of the Rh0.5Cr1.5O3 cocatalyst was 0.2 wt%. The apparent quantum yield (AQY) at 340 nm of the optimized Rh0.5Cr1.5O3(0.2 wt%)/AgTaO3 photocatalyst reached to about 40%. Rh0.5Cr1.5O3(0.2 wt%)/AgTaO3 gave a solar to hydrogen conversion efficiency (STH) of 0.13% for photocatalytic water splitting under simulated sunlight irradiation. Bubbles of gasses evolved by the solar water splitting were visually observed under atmospheric pressure at room temperature.
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