62 research outputs found
The Ruijsenaars-Schneider Model in the Context of Seiberg-Witten Theory
The compactification of five dimensional N=2 SUSY Yang-Mills (YM) theory onto
a circle provides a four dimensional YM model with N=4 SUSY. This supersymmetry
can be broken down to N=2 if non-trivial boundary conditions in the compact
dimension, \phi(x_5 +R) = e^{2\pi i\epsilon}\phi(x_5), are imposed on half of
the fields. This two-parameter (R,\epsilon) family of compactifications
includes as particular limits most of the previously studied four dimensional
N=2 SUSY YM models with supermultiplets in the adjoint representation of the
gauge group. The finite-dimensional integrable system associated to these
theories via the Seiberg-Witten construction is the generic elliptic
Ruijsenaars-Schneider model. In particular the perturbative (weak coupling)
limit is described by the trigonometric Ruijsenaars-Schneider model.Comment: 18 pages, LaTe
Entropic C-theorems in free and interacting two-dimensional field theories
The relative entropy in two-dimensional field theory is studied on a cylinder
geometry, interpreted as finite-temperature field theory. The width of the
cylinder provides an infrared scale that allows us to define a dimensionless
relative entropy analogous to Zamolodchikov's function. The one-dimensional
quantum thermodynamic entropy gives rise to another monotonic dimensionless
quantity. I illustrate these monotonicity theorems with examples ranging from
free field theories to interacting models soluble with the thermodynamic Bethe
ansatz. Both dimensionless entropies are explicitly shown to be monotonic in
the examples that we analyze.Comment: 34 pages, 3 figures (8 EPS files), Latex2e file, continuation of
hep-th/9710241; rigorous analysis of sufficient conditions for universality
of the dimensionless relative entropy, more detailed discussion of the
relation with Zamolodchikov's theorem, references added; to appear in Phys.
Rev.
Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles
We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus, X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage
What Physical Processes Drive the Interstellar Medium in the Local Bubble?
Recent 3D high-resolution simulations of the interstellar medium in a star form-
ing galaxy like the Milky Way show that supernova explosions are the main driver of the
structure and evolution of the gas. Its physical state is largely controlled by turbulence due
to the high Reynolds numbers of the average flows. For a constant supernova rate a dynam-
ical equilibrium is established within 200 Myr of simulation as a consequence of the setup
of a galactic fountain. The resulting interstellar medium reveals a typical density/pressure
pattern, i.e. distribution of so-called gas phases, on scales of 500–700 pc, with interstellar
bubbles being a common phenomenon just like the Local Bubble and the Loop I superbub-
ble, which are assumed to be interacting. However, modeling the Local Bubble is special,
because it is driven by a moving group, passing through its volume, as it is inferred from
the analysis of Hipparcos data. A detailed analysis reveals that between 14 and 19 super-
novae have exploded during the last 15 Myr. The age of the Local Bubble is derived from
comparison with HI and UV absorption line data to be 14.5±0.7
Myr. We further predict the
0.4merging of the two bubbles in about 3 Myr from now, when the interaction shell starts to
fragment. The Local Cloud and its companion HI clouds are the consequence of a dynamical
instability in the interaction shell between the Local and the Loop I bubble
FUV and X-ray absorption in the Warm-Hot Intergalactic Medium
The Warm-Hot Intergalactic Medium (WHIM) arises from shock-heated gas
collapsing in large-scale filaments and probably harbours a substantial
fraction of the baryons in the local Universe. Absorption-line measurements in
the ultraviolet (UV) and in the X-ray band currently represent the best method
to study the WHIM at low redshifts. We here describe the physical properties of
the WHIM and the concepts behind WHIM absorption line measurements of H I and
high ions such as O VI, O VII, and O VIII in the far-ultraviolet and X-ray
band. We review results of recent WHIM absorption line studies carried out with
UV and X-ray satellites such as FUSE, HST, Chandra, and XMM-Newton and discuss
their implications for our knowledge of the WHIM.Comment: 26 pages, 9 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 3; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
Baryons: What, When and Where?
We review the current state of empirical knowledge of the total budget of
baryonic matter in the Universe as observed since the epoch of reionization.
Our summary examines on three milestone redshifts since the reionization of H
in the IGM, z = 3, 1, and 0, with emphasis on the endpoints. We review the
observational techniques used to discover and characterize the phases of
baryons. In the spirit of the meeting, the level is aimed at a diverse and
non-expert audience and additional attention is given to describe how space
missions expected to launch within the next decade will impact this scientific
field.Comment: Proceedings Review for "Astrophysics in the Next Decade: JWST and
Concurrent Facilities", ed. X. Tielens, 38 pages, 10 color figures. Revised
to address comments from the communit
A comparison between the diets of pregnant diabetic women and pregnant non-diabetic women
In order to assess the effect of dietary advice for pregnant diabetic women, the habitual dietary intake of 8 pregnant diabetic women was assessed by 7-day weighed food records. These results were compared with records from 8 non-diabetic women, matched for age and gestation. Despite intense personalized dietetic advice to the diabetic women, there were no statistically significant differences in macro-nutrient intake between the two groups. The diabetic women were encouraged to increase their carbohydrate intake slightly, but failed to achieve current British Diabetic Association dietary recommendations with respect to percent energy from carbohydrate (41 ± 5 (± SE)(range 29–47)%, BDA recommendation >50%) and percentage from fat 43 ± 6 (33–51)%, BDA recommendation <30%). Intake of bread and cereals was increased in the diabetic women, but increases in complex carbohydrates were insufficient to compensate for a reduced intake of high-sugar foods. Intakes of energy from simple sugars were significantly lower (p < 0–05) in the diabetic group (12 ± 2 (5–20)%) than in the non-diabetic group (21 ± 2 (12–28)%). There was no detectable difference in sources of fats in the diet between the two groups
Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles
We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus, X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage.This research was supported by the University of Catania (Project Emergent Pests and Pathogens and Relative Sustainable Strategies - 5A722192113; PhD fellowship to AG). P.H.W.B. was supported by the German Research Foundation (DFG Emmy Noether Grant BI 1956/1–1). Funding to MGW: USDA-NIFA, ARS and APHIS; ISDA Hatch; Hawaii Dept. of Agriculture. JH and YL were funded by the USDA APHIS and USDA Forest Service. HK was partially supported by Japan Society for the Promotion of Science (Grant-in-Aid for Scientific Research, KAKENHI, Nos. 18KK0180, 19H02994 and 20H03026). KH was partially supported by Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (Capes, Brazil; Finance code 001). Open access funding provided by UniversitĂ degli Studi di Catania within the CRUI-CARE Agreement
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