101 research outputs found
An Experience on Environmental Education based on Respect-Reduce-Reuse-Recycle in a Village Primary School in the Marche Region, in Italy
T
he importance of environmental educatio n is widely recognized worldwide: an important objective is that the
citizens are accustomed to apply the best available practices in their life , while ask ing the administration and the
government to gradually enforce measures lead ing to a reduction of the environmental impact and to a more
sustainable lifestyle. This requires a formation starting at an early age: however, in Italy the relevant indications from
the National Curriculum are still limited and do not suggest explicitly the performance of any pr actical activity ,
tailored on the specific school setting . This inadequacy of the Curriculum becomes particularly apparent in cases
where other concerns are present, for example the areas in the Marche region affected by the 2016 earthquake : here,
the need to resum e a day by day routine put a kind of \u201cdamper\u201d on other questions, such as environmental issues .
This had an effect also i n children\u2019s life on this question, school needs to take a stand , which is the objective of this
study . This work concerns an approach to environmental education in a multi classes primary school context (age
6 10) in a small village school, located in the Central Apennine in Italy. This is performed through an experience
carried out by investigating the behavior towards waste p roduction of the community, as perceived by children at
school. It is therefore articulated through the application of 4R (Respect, which encompasses Reduce, Reuse and
Recycle) applying and extending the indications from the Italian National Curriculum. Th e project leads also to an
experience of self production of objects by the use of waste, to improve their awareness of the possibilities included
in their upcycling. Feedback on the experience is finally acquired from the children and discussed, especially in the
sense of creating future citizens with a more sensible and reasonable behavior towards the environment and leading
possibly to zero waste strategies in their family and work setting. The data were analy z ed using thematic analysis
and different them es about waste production were singled out
An Experience on Environmental Education Based on Respect-Reduce-Reuse-Recycle in a Village Primary School in the Marche Region, in Italy
The importance of environmental education is widely recognized worldwide: an important objective is that the
citizens are accustomed to apply the best available practices in their life, while asking the administration and the
government to gradually enforce measures leading to a reduction of the environmental impact and to a more
sustainable lifestyle. This requires a formation starting at an early age: however, in Italy the relevant indications
from the National Curriculum are still limited and do not suggest explicitly the performance of any practical
activity, tailored on the specific school setting. This inadequacy of the Curriculum becomes particularly apparent
in cases where other concerns are present, for example the areas in the Marche region affected by the 2016
earthquake: here, the need to resume a day-by-day routine put a kind of âdamperâ on other questions, such as
environmental issues. This had an effect also in childrenâs life: on this question, school needs to take a stand, which
is the objective of this study. This work concerns an approach to environmental education in a multi-classes
primary school context (age 6-10) in a small village school, located in the Central Apennine in Italy. This is
performed through an experience carried out by investigating the behavior towards waste production of the
community, as perceived by children at school. It is therefore articulated through the application of 4R (Respect,
which encompasses Reduce, Reuse and Recycle) applying and extending the indications from the Italian National
Curriculum. The project leads also to an experience of self-production of objects by the use of waste, to improve
their awareness of the possibilities included in their upcycling. Feedback on the experience is finally acquired from
the children and discussed, especially in the sense of creating future citizens with a more sensible and reasonable
behavior towards the environment and leading possibly to zero-waste strategies in their family and work setting.
The data were analyzed using thematic analysis and different themes about waste production were singled out
Dynamical properties of Molecular Cloud Complexes at the Epoch of Reionization
AbstractThe Atacama Large (Sub-)millimeter Array (ALMA) has provided glimpse of the interstellar medium (ISM) properties of galaxies at the Epoch of Reionization (EoR); however, detailed understanding of their internal structure is still lacking. We present properties of molecular cloud complexes (MCCs) in a prototypical galaxy at this epoch studied in cosmological zoom-in simulations (Leung et al. 2019c). Typical MCC mass and size are comparable to nearby spirals and starburst galaxies (MgasâŒ106.5MÈŻ and Râ45â100 pc). MCCs are highly supersonic, with velocity dispersion of Ïgasâ20â100 km sâ1 and pressure of P/kB â107.6Kcmâ3, which are comparable to gas-rich starburst galaxies. In addition, we perform stability analysis to understand the origin and dynamical properties of MCCs. We find that MCCs are globally stable in the main disk of AlthĂŠa. Densest regions where star formation is expected to take place in clumps and cores on even smaller scales instead have lower virial parameter and Toomre-Q values. Detailed studies of the star-forming gas dynamics at the EoR thus require a spatial resolution of < 40 pc ( â 0.01âł), which is within reach of ALMA, to complement studies of stellar populations at EoR using the James Webb Space Telescope (JWST)
Dynamical Properties of Molecular-forming Gas Clumps in Galaxies at the Epoch of Reionization
We study the properties of molecular-forming gas clumps (MGCs) at the epoch
of reionization using cosmological zoom-in simulations. We identify MGCs in a
z=6 prototypical galaxy ("Althaea") using an H2 density-based clump finder. We
compare their mass, size, velocity dispersion, gas surface density, and virial
parameter (alpha_vir) to observations. In Althaea, the typical MGC mass and
size are Mgas=10^6.5 Msun and R=45-100 pc, which are comparable to those found
in nearby spirals and starburst galaxies. MGCs are highly supersonic and
supported by turbulence, with rms velocity dispersions of sigma_gas=20-100 km
s^-1 and pressure of P/k_B=10^7.6 K cm^-3 (i.e., >1000x with respect to the
Milky Way), similar to those found in nearby and z~2 gas-rich starburst
galaxies. In addition, we perform stability analysis to understand the origin
and dynamical properties of MGCs. We find that MGCs are globally stable in the
main disk of Althaea. Densest regions where star formation is expected to take
place in clouds and cores on even smaller scales instead have lower alpha_vir
and Toomre-Q values. Detailed studies of the star-forming gas dynamics at the
epoch of reionization thus require a spatial resolution of <40 pc (=0.01"),
which is within reach with the Atacama Large (sub-)Millimeter Array and the
Next Generation Very Large Array.Comment: 16 pages, 10 figures, ApJ accepte
The black hole and host galaxy growth in an isolated QSO observed with ALMA
The outstanding mass growth of supermassive black holes (SMBHs) at the
Reionisation Epoch and how it is related to the concurrent growth of their host
galaxies, poses challenges to theoretical models aimed at explaining how these
systems formed in short timescales (<1 Gyr). To trace the average evolutionary
paths of quasi-stellar objects (QSOs) and their host galaxies in the BH
mass-host mass () plane, we compare the star formation rate (SFR),
derived from the accurate estimate of the dust temperature and the dust mass
(), with the BH accretion rate. To this aim, we
analysed a deep, pc resolution ALMA observation of the sub-mm continuum,
[CII] and HO of the QSO J2310+1855, enabling a detailed study of
dust properties and cold gas kinematics. We performed an accurate SED analysis
obtaining a dust temperature of K and a dust mass of
. The implied AGN-corrected SFR
is , a factor of 2 smaller than previously
reported for this QSO. We derived the best estimate of the dynamical mass
within kpc, based on
a dynamical model of the system. We found that , suggesting that AGN feedback might be efficiently
acting to slow down the SMBH accretion, while the stellar mass assembly is
still vigorously taking place in the host galaxy. In addition, we were also
able to detect high-velocity emission on the red and blue sides of the [CII]
emission line, that traces a gaseous outflow, and for the first time, we mapped
a spatially-resolved water vapour disk through the HO v=0
emission line detected at GHz,
whose kinematic properties and size are broadly consistent with those of the
[CII] disk.Comment: 15 pages, 10 figures, 4 tables. Accepted in A&
Black hole and host galaxy growth in an isolated z 6 QSO observed with ALMA
The outstanding mass growth of supermassive black holes (SMBHs) at the epoch of reionisation and its relation to the concurrent growth of their host galaxies poses challenges to theoretical models aimed at explaining how these systems formed on short timescales (< 1 Gyr). To trace the average evolutionary paths of quasi-stellar objects (QSOs) and their host galaxies in the plane of BH mass to host mass (Mdyn), we compare the star formation rate (SFR), derived from the accurate estimate of the dust temperature and the dust mass (Tdust,âMdust) based on infrared and sub-millimeter (sub-mm) spectral energy distribution (SED), with the BH accretion rate, derived from Lbol based on X-ray and optical and ultraviolet SED. To this aim, we analysed a deep ALMA observation of the sub-mm continuum, [CII], and H2O of the zââŒâ6 QSO J2310+1855 with a resolution of 900 pc, which enabled a detailed study of dust properties and cold gas kinematics. We performed an accurate SED analysis obtaining a dust temperature of Tdustâ=â71â
屉
4 K, dust mass Mdustâ=â(4.4â
屉
0.7)Ă108âMâ, and total far-infrared luminosity of LTIR = 2.5â0.5+0.6 Ă 1013 Lâ. The implied active galactic nuclei (AGN) â corrected SFR = 1240â260+310 Mâ yrâ1 is a factor of 2 lower than previously reported for this QSO. We measured a gas-to-dust ratio of GDRâ=â101â
屉
20. The dust continuum and [CII] surface brightness profiles are spatially extended out to rââŒâ6.7 kpc and rââŒâ5 kpc, respectively, with half-light radii of 0.9 and 1.1 kpc for the dust and gas, respectively. The derived gas surface density, ÎŁgas, and star formation rate density, ÎŁSFR, place the J2310+1855 host galaxy above the Kennicutt-Schmidt relation. We derived a best estimate of the dynamical mass Mdynâ=â5.2â
Ăâ
1010âMâ within râ=â1.7 kpc based on a dynamical model of the system with a rotating disk inclined at iâ=â25 deg. The Toomre parameter profile across the disk is QgasââŒâ3 and implies that the disk is unstable. We found that SFR/Mdyn > áčBH/MBH, suggesting that AGN feedback might be efficiently acting to slow down the SMBH accretion, while stellar mass assembly is still vigorously taking place in the host galaxy. In addition, we were also able to detect high-velocity emission on the red and blue sides of the [CII] emission line that is not consistent with disk rotation and traces a gaseous outflow. We derived an outflow mass Moutâ=â3.5â
Ăâ
108âMâ, and a mass outflow rate in the range áčout = 1800 â 4500 Mâ yrâ1. The implied Äout ⌠0.0005 â 0.001 Lbol is in agreement with the values observed for ionised winds. For the first time, we mapped a spatially resolved water vapour disk through the H2O vâ=â0 3(2,â2)â
ââ
3(1,â3) emission line detected at Îœobsâ=â274.074 GHz, whose kinematic properties and size are broadly consistent with those of the [CII] disk. The luminosity ratio LH2O/LTIRâ=â1.4â
Ăâ
10â5 is consistent with line excitation by dust-reprocessed star formation in the interstellar medium of the host galaxy
Metal Enrichment in the Reionization Epoch
The presence of elements heavier than helium ("metals") is of fundamental
importance for a large number of astrophysical processes occurring in planet,
star and galaxy formation; it also affects cosmic structure formation and
evolution in several ways. Even a small amount of heavy elements can
dramatically alter the chemistry of the gas, opening the path to complex
molecules. Metals might enhance the ability of the gas to radiate away its
thermal energy, thus favoring the formation of gravitationally bound objects;
they can also condensate in a solid phase (dust grains), partly or totally
blocking radiation from luminous sources. Finally, they represent useful
tracers of energy deposition by stars and probe the physical properties of the
environment by absorption or emission lines. Last, but certainly not least,
life -- as we know it on Earth -- is tightly related to the presence of at
least some of the heavy elements. In this pedagogical review I will concentrate
on the connection between early metal enrichment and cosmic reionization. As we
will see these two processes are intimately connected and their joint study
might turn out to be fundamental in understanding the overall evolution of the
Universe during the first billion years after the Big Bang, an epoch
corresponding to redshifts z>6.Comment: Book chapter in Understanding the Epoch of Cosmic Reionization:
Challenges and Progress, Springer International Publishing, Ed. Andrei
Mesinger, ISBN 978-3-319-21956-1. arXiv admin note: text overlap with
arXiv:astro-ph/0007248 by other author
Dolichol: A Component of the Cellular Antioxidant Machinery
Dolichol, an end product of the mevalonate pathway, has been proposed a biomarker of aging, but its biological role, not to mention its catabolism, has not been fully understood. UV-B radiation was used to induce oxidative stress in isolated rat hepatocytes by the collagenase method. Effects on dolichol, phospholipids-bound polyunsaturated fatty acids (PL PUFA) and known lipid soluble antioxidants [coenzyme Q (CoQ) and α-tocopherol] were studied. The increase in oxidative stress was detected by a probe sensitive to reactive oxygen species (ROS). Peroxidation of lipids was assessed by measuring the release of thiobarbituric acid reactive substances (TBARS). Dolichol, CoQ and α-tocopherol were assessed by high-pressure liquid chromatography (HPLC), PL PUFA by gas-liquid chromatography (GC). UV-B radiation caused an immediate increase in ROS as well as lipid peroxidation and a simultaneous decrease in the levels of dolichol and lipid soluble antioxidants. Decrease in dolichol paralleled changes in CoQ levels and was smaller than that in α-tocopherol. The addition of mevinolin, a competitive inhibitor of the enzyme 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoAR), magnified the loss of dolichol and was associated with an increase in TBARS production. Changes in PL PUFA were minor. These findings highlight that oxidative stress has very early and similar effects on dolichol and lipid soluble antioxidants. Lower levels of dolichol are associated with enhanced peroxidation of lipids, which suggest that dolichol may have a protective role in the antioxidant machinery of cell membranes and perhaps be a key to understanding some adverse effects of statin therapy
Unveiling [CII] clumps in a lensed star-forming galaxy at z ~ 3.4
Observations at UV and optical wavelengths have revealed that galaxies at
z~1-4 host star-forming regions, dubbed "clumps", which are believed to form
due to the fragmentation of gravitationally unstable, gas-rich disks. However,
the detection of the parent molecular clouds that give birth to such clumps is
still possible only in a minority of galaxies, mostly at z~1. We investigated
the [CII] and dust morphology of a z~3.4 lensed galaxy hosting four clumps
detected in the UV continuum. We aimed to observe the [CII] emission of
individual clumps that, unlike the UV, is not affected by dust extinction, to
probe their nature and cold gas content. We conducted ALMA observations probing
scales down to ~300 pc and detected three [CII] clumps. One (dubbed "NE")
coincides with the brightest UV clump, while the other two ("SW" and "C") are
not detected in the UV continuum. We do not detect the dust continuum. We
converted the [CII] luminosity of individual clumps into molecular gas mass and
found Mmol~10^8 Msun. By complementing it with the star formation rate (SFR)
estimate from the UV continuum, we estimated the gas depletion time (tdep) of
clumps and investigated their location in the Schmidt-Kennicutt plane. While
the NE clump has a short tdep=0.16 Gyr, comparable with high-redshift
starbursts, the SW and C clumps instead have longer tdep>0.65 Gyr and are
likely probing the initial phases of star formation. The lack of dust continuum
detection is consistent with the blue UV continuum slope estimated for this
galaxy (beta~-2.5) and it indicates that dust inhomogeneities do not
significantly affect the detection of UV clumps in this target. We pushed the
observation of the cold gas content of individual clumps up to z~3.4 and showed
that the [C II] line emission is a promising tracer of molecular clouds at high
redshift, allowing the detection of clumps with a large range of depletion
times.Comment: Accepted for publication in A&
The ALMA REBELS Survey: The First Infrared Luminosity Function Measurement at $\mathbf{z \sim 7}
We present the first observational infrared luminosity function (IRLF)
measurement in the Epoch of Reionization (EoR) based on a UV-selected galaxy
sample with ALMA spectroscopic observations. Our analysis is based on the ALMA
large program Reionization Era Bright Emission Line Survey (REBELS), which
targets 42 galaxies at with [CII] 158\micron line scans.
16 sources exhibit a dust detection, 15 of which are also spectroscopically
confirmed through the [CII] line. The IR luminosities of the sample range from
to 12.2. Using the UVLF as a proxy to derive the
effective volume for each of our target sources, we derive IRLF estimates, both
for detections and for the full sample including IR luminosity upper limits.
The resulting IRLFs are well reproduced by a Schechter function with the
characteristic luminosity of . Our
observational results are in broad agreement with the average of predicted
IRLFs from simulations at . Conversely, our IRLFs lie significantly
below lower redshift estimates, suggesting a rapid evolution from to
, into the reionization epoch. The inferred obscured contribution to
the cosmic star-formation rate density at amounts to
which is at
least 10\% of UV-based estimates. We conclude that the presence of dust
is already abundant in the EoR and discuss the possibility of unveiling larger
samples of dusty galaxies with future ALMA and JWST observations.Comment: 9 pages, 5 figure
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