1,217 research outputs found
How Predictable are Temperature-series Undergoing Noise-controlled Dynamics in the Mediterranean
Mediterranean is thought to be sensitive to global climate change, but its future interdecadal variability is uncertain for many climate models. A study was made of the variability of the winter temperature over the Mediterranean Sub-regional Area (MSA), employing a reconstructed temperature series covering the period 1698 to 2010. This paper describes the transformed winter temperature data performed via Empirical Mode Decomposition for the purposes of noise reduction and statistical modeling. This emerging approach is discussed to account for the internal dependence structure of natural climate variability
VLT/VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies: 2D kinematic properties
We present and discuss the 2D kinematic properties of the ionized gas
(Halpha) in a sample of 38 local (ultra) luminous infrared galaxies [(U)LIRGs]
(31 LIRGs and 7 ULIRGs) observed with VIMOS at the VLT using integral field
spectroscopy. This sample covers well the less studied LIRG luminosity range
and includes isolated disks, interacting systems, and mergers. The majority of
the galaxies have two main kinematically distinct components. One component
(i.e., narrow or systemic) extends over the whole line-emitting region and is
characterized by small to intermediate velocity dispersions (i.e., sigma from
30 to 160 km s^-1). It traces the overall velocity field. The second component
(broad) has in general a larger velocity dispersion (up to 320 km s^-1), mainly
found in the inner regions and generally blueshifted with respect to the
systemic component. Most of the objects (76%) are dominated by rotation, more
relevant in LIRGs than in ULIRGs. Isolated disks, interacting galaxies, and
merging systems define a sequence of increasing mean velocity dispersion, and
decreasing velocity field amplitude.The LIRGs classified as isolated disks have
similar velocity amplitudes but larger mean velocity dispersions (44 vs. 24 km
s^-1) than local spirals, implying a larger turbulence and thicker disks.
Interacting systems and mergers have values closer to those of low velocity
dispersion ellipticals/lenticular galaxies (E/SOs). The (U)LIRGs classified as
mergers have kinematic properties similar to those shown by the Lyman break
analogs (LBAs). The dynamical masses range from \sim 0.04 m* to 1.4 m* (i.e.,
m* = 1.4x10^{11} Msun), with ULIRGs (M{dyn} sim 0.5 +/- 0.2 m*) being more
massive than LIRGs by, on average, a factor of about 2. The mass ratio of
individual pre-coalescence galaxies is <2.5 for most of the systems, confirming
that most (U)LIRG mergers involve sub-m* galaxies of similar mass.Comment: 66 pages, 5 figures plus 45 figures in App. A; accepted for
publication in A&
The Strategic Importance of Taiwan to the United States and Its Allies: Part Two â Policy since the Start of the Russia-Ukraine War
Taiwan has become increasingly important to the United States and its allies as the Russia-Ukraine War has united democracies against authoritarian expansionism and indeed has developed an international democracy-authoritarianism dynamic in global affairs. Part one of this article clearly outlined the geopolitical, economic, and soft-power reasons why Taiwan is strategically important. Part two reviews the development of US and allied policy statements on Taiwanâfrom the invasion of Ukraine in 2022 to the presentâand provides policymakers and military strategists with incremental but realistic recommendations for understanding the current dynamic of the region and fashioning responses to deter further authoritarian aggression
QSO2 outflow characterization using data obtained with OSIRIS at the Gran Telescopio Canarias
Ionized outflows are ubiquitous in non radio-loud obscured quasars (QSO2s) at
different redshifts. We search for large-scale ionized outflows associated with
six optically selected QSO2 (five non-radio-loud and one radio-loud) at
0.2-0.5, targeting objects with extended radio structures. We have obtained
OSIRIS/GTC optical long slit spectroscopy data for these six QSO2 with the slit
located along the radio axis. We traced the gas kinematics with the
[OIII]4959,5007 lines to investigate ionized outflows and characterize
the dynamical state of the host galaxies. This second study has been
complemented with previously published FORS2/VLT spectroscopic data of 13 more
QSO2 at similar z. We identify ionized outflows in four out of the six QSO2
observed with the GTC. The outflows are spatially unresolved in two QSO2 and
compact in a third (radial size of R=0.80.3 kpc). Of particular interest
is the radio-quiet QSO2 SDSS 0741+3020 at z=0.47, associated with a giant
112 kpc nebula. An ionized outflow probably induced by the radio
structures has been detected along the axis defined by the central
1\arcsec\ radio structure, extending up to at least 4 kpc from the
active galactic nucleus (AGN). Turbulent gas (130 km s) has
also been detected across the giant gas nebula up to 40 kpc from the AGN.
This turbulence may have been induced by outflows triggered by the interaction
between a so-far undetected large-scale radio source and the nebula. Regarding
the dynamical state of the host galaxies, we find that the majority of the QSO2
show v/ 1, implying that they are dominated by random motions
(so-called dispersion-dominated systems). Most (17 of 19) fall in the area of
the E/S0 galaxies in the dynamical diagram v/ versus . None are
consistent with spiral or disk galaxies.Comment: 27 pages, 11+8 figures, accepted for publication in A&
Ionized gas outflows and global kinematics of low-z luminous star forming galaxies
We study the kinematic properties of the ambient ionized ISM and ionized gas
outflows in a large and representative sample of local luminous and
ultraluminous infrared galaxies (U/LIRGs) (58 systems, 75 galaxies), on the
basis of integral field spectroscopy (IFS)-based high S/N integrated spectra at
galactic and sub-galactic, i.e. star forming (SF) clumps, scales.
Ambient ionized gas. The velocity dispersion of the ionized ISM in U/LIRGs
( ~ 70 kms-1) is larger than in lower luminosity local star forming
galaxies ( ~ 25 kms-1). While for isolated disc LIRGs star formation
appears to sustain turbulence, gravitational energy release associated to
interactions and mergers plays an important role driving sigma in the U/LIRG
range. We also find that the impact of an AGN in ULIRGs is strong, increasing
sigma by a factor 1.5 on average. The observed weak dependency of sigma with
SFR surface density for local U/LIRGs is in very good agreement with that
measured in some high-z samples.
Ionized outflows. The presence of ionized gas outflows in U/LIRGs seems
universal based on the detection of a broad, usually blueshifted, Halpha line.
AGNs in U/LIRGs are able to generate faster (x2) and more massive (x1.4)
ionized gas outflows than pure starbursts. The derived ionized mass loading
factors are in general below one, with only a few AGNs above this limit. Only a
small fraction of the ionized material from low mass LIRGs (log(Mdyn/Msun) <
10.4) could reach the intergalactic medium, with more massive galaxies
retaining the gas. The observed average outflow properties in U/LIRGs are
similar to high-z galaxies of comparable SFR. In the bright SF clumps found in
LIRGs, ionized gas outflows appear to be very common. For a given SFR surface
density, outflows in LIRG clumps would be about one to two orders of magnitude
less energetic than those launched by clumps in high-z SF galaxies.Comment: 36 pages, 20 figures, 6 tables. Accepted for publication in A&
The Strategic Importance of Taiwan to the United States and Its Allies: Part One
This article presents four factors to consider in evaluating Taiwanâs strategic importance to the United States and its allies and answers a question often raised at forums concerning the Indo-Pacific: âWhy should the United States careâ about this small island in the Pacific? The response often given is simply US credibility, and while this is an important factor, this article reviews a wider array of possible factors to consider when answering that question. The study of these factors should assist US military and policy practitioners in accurately evaluating the related strategic environment. Through a survey of official US policy statements and strategy documents across administrations, part two of this article (to be featured in a future issue) will examine the evolving US perception of Taiwan throughout the aggressive strengthening of China and during Taiwanâs domestic political development into a full-fledged democracy
Rule-based Handling of Hazardous Nitrogen
A rule-based, recursive framework is an ideal approach to support the design of cropping systems (CS). A framework of this type was proposed, arranged into three stages (Silvestri and Bellocchi, 2007): (phase I) prior evaluation (technical, problem-solving, farmer-driven stage), (phase II) posterior evaluation (institutional, environmental monitoring implemented when CS response deviates from expected behaviour), and (phase III) managing the change (participatory, dynamic rearrangement of CS). This sequence is meant to evolve and grow over time through reiterations (Fig. 1), allowing for a continuous adaptation of agricultural productions systems as the business environment and society change. The same procedure was applied in this study to assess the behaviour of an array of CS run in the proximity of Lake Massaciuccoli - an area of Central Italy currently defined as âvulnerable areaâ under EU Directive 676/91 - as part of an action aimed at identifying possible responsibilities of farmers in NO3 contamination of waters (research developed in 2005-2006 under the Italian Ministry of Education, University and Research)
âI was proud of myself that I didn't give up and I did itâ: Experiences of pride and triumph in learning science
The role that specific emotions, such as pride and triumph, play during instruction in science education is an underresearched field of study. Emotions are recognized as central to learning yet little is known about the way in which they are produced in naturalistic settings, how emotions relate to classroom learning during interactions, and what antecedent factors are associated with emotional experiences during instruction. Data sources for the study include emotion diaries, student written artifacts, video recordings of class interactions, and interviews. Emotions produced in the moment during classroom interactions are analyzed from video data and audio data through a novel theoretical framework related to the sociology of human emotions. These direct observations are compared with studentsâ recollected emotional experiences reported through emotion diaries and interviews. The study establishes links between pride and triumph within classroom interactions and instructional tasks during learning episodes in a naturalistic setting. We discuss particular classroom activities that are associated with justified feelings of pride and triumph. More specifically, classroom events associated with these emotions were related to understanding science concepts, social interactions, and achieving success on challenging tasks
Rainfall Erosivity in Soil Erosion Processes
This book gathers recent international research on the association between aggressive rainfall and soil loss and landscape degradation. Different contributions explore these complex relationships and highlight the importance of the spatial patterns of precipitation intensity on land flow under erosive storms, with the support of observational and modelling data. This is a large and multifaceted area of research of growing importance that outlines the challenge of protecting land from natural hazards. The increase in the number of high temporal resolution rainfall records together with the development of new modelling capabilities has opened up new opportunities for the use of large-scale planning and risk prevention methods. These new perspectives should no longer be considered as an independent research topic, but should, above all, support comprehensive land use planning, which is at the core of environmental decision-making and operations. Textbooks such as this one demonstrate the significance of how hydrological science can enable tangible progress in understanding the complexity of water management and its current and future challenges
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