232 research outputs found
Management and restoration of Italian afforestations under global change
As a consequence of past deforestation, degraded areas in Italy have been subjected to afforestation since the beginning of the XXI century. These afforestations have been done mainly with conifers (Pinus nigra, Pinus pinaster, Pinus halepensis, Pinus pinea), and with the aim to 1) protect the soil and to 2) prevent floods. Exotic forest tree species have been used for the afforestation of selected sites of the Apennine. In the case of Douglas fir, it is possible to state that after ninety years the results are very good in terms of both ecological adaptability and high growth-rate.Nowadays, the lack of silvicultural treatments, the ageing processes, insect and fungi outbreaks have led pine afforestations to a condition of an unsteady biological equilibrium in many sites. Moreover, this condition seems to be due to additional factors related to climate change such as wind storms and dryness. The restoration of these pine afforestations is therefore one of the main aims of the present Italian forest management policy which aims to increase their level of resilience. In particular, the priority of the researchers has been given to the most fragile stands where three possible objectives of restoration measures should be considered:To rehabilitate conifer stands by introducing native broadleaves when these stands are in a very degraded condition, and when the local wood energy chain needs to be started;To conserve the conifer stands in the cases where the cultural, aesthetic and recreational functions, are the prevailing obtainable ecosystem services;To foster the mixed stands, with the conifers of the old cycle and native broadleaves, which could increase resilience to the extreme events.In regards of Douglas-fir stands, new silvicultural models have been developed which aim to a) conserve these stands and to b) combine a higher growth rate with a much improved mechanical tree stability
Soccer-related craniomaxillofacial injuries
The authors assessed the rate of craniomaxillofacial fractures in soccer and the areas where they occur, describing above all the injury pattern of this sport. Over a 5-year period (1995-2000) 46 cases of 329 with fractures associated with different sports activities have been surgically operated at the maxillofacial surgery department of the Policlinico "Umberto I" Hospital, University "La Sapienza" of Rome. All data collected have been selected on the basis of sex, age, anatomic site of the fracture, and the practiced sport. Information on injury patterns, severity, and play circumstances have been documented. The department examined 7 sports disciplines, but soccer was responsible for sports-related maxillofacial fractures in 34 of 46 cases (73.9%). All 34 fractures occurred to men. In soccer, the zygomatic and nasal regions are mainly involved. In fact the authors examined zygomatic fractures in 15 cases and nasal fractures in 10 cases. Direct contact between players generally causes soccer-related maxillofacial fractures: head-elbow impacts (21 cases) or head-head impacts (14 cases). The male:female ratio is 6.6:1, while the average age is 25 years for males and 23 years for females. In comparison with other sports (rugby, football, etc.) where physical contact occurs more frequently and the higher incidence of traumatic events justifies the use of protective measures, soccer is not a particularly violent sport. In soccer, maxillofacial traumas are caused by violent impacts between players that take place mainly when the ball is played with the forehead. In this moment there can be an elbow-head impact or a head-head impact. The authors believe that the low incidence of fractures, severity of the lesions, and discomfort caused by possible protective masks make their use unjustified. The data collected during this study witness that in soccer 21 of 34 cases of maxillofacial fractures are caused by elbow-head impacts. This fact suggests a preventive strategy against violent behavior in soccer play. Because the use of any sort of helmet proved impossible, the introduction of more severe penalties and a greater respect for the rules of the game by the players could reduce the percentage of impacts during matches. Impacts cause the most serious and frequent lesions in the maxillofacial region
The Variation of the Galaxy Luminosity Function with Group Properties
We explore the shape of the galaxy luminosity function (LF) in groups of
different mass by creating composite LFs over large numbers of groups.
Following previous work using total group luminosity as the mass indicator,
here we split our groups by multiplicity and by estimated virial (group halo)
mass, and consider red (passive) and blue (star forming) galaxies separately.
In addition we utilise two different group catalogues (2PIGG and Yang et al.)
in order to ascertain the impact of the specific grouping algorithm and further
investigate the environmental effects via variations in the LF with position in
groups. Our main results are that LFs show a steepening faint end for early
type galaxies as a function of group mass/ multiplicity, with a much suppressed
trend (evident only in high mass groups) for late type galaxies. Variations
between LFs as a function of group mass are robust irrespective of which
grouping catalogue is used, and broadly speaking what method for determining
group `mass' is used. We find in particular that there is a significant deficit
of low-mass passive galaxies in low multiplicity groups, as seen in high
redshift clusters. Further to this, the variation in the LF appears to only
occur in the central regions of systems, and in fact seems to be most strongly
dependent on the position in the group relative to the virial radius. Finally,
distance-rank magnitude relations were considered. Only the Yang groups
demonstrated any evidence of a correlation between a galaxy's position relative
to the brightest group member and its luminosity. 2PIGG possessed no such
gradient, the conclusion being the FOF algorithm suppresses the signal for weak
luminosity--position trends and the Yang grouping algorithm naturally enhances
it.Comment: 20 pages, 29 figures, accepted for submission to MNRA
Systematic search for lensed X-ray sources in the CLASH fields
We search for unresolved X-ray emission from lensed sources in the FOV of 11
CLASH clusters with Chandra data. We consider the solid angle in the lens plane
corresponding to a magnification , that amounts to a total of ~100
arcmin. Our main goal is to assess the efficiency of massive clusters as
cosmic telescopes to explore the faint end of X-ray extragalactic source
population. We search for X-ray emission from strongly lensed sources
identified in the optical, and perform an untargeted detection of lensed X-ray
sources. We detect X-ray emission only in 9 out of 849 lensed/background
optical sources. The stacked emission of the sources without detection does not
reveal any signal in any band. Based on the untargeted detection, we find 66
additional X-ray sources that are consistent with being lensed sources. After
accounting for completeness and sky coverage, we measure for the first time the
soft- and hard-band number counts of lensed X-ray sources. The results are
consistent with current modelization of the AGN population distribution. The
distribution of de-lensed fluxes of the sources identified in moderately deep
CLASH fields reaches a flux limit of ~ and ~ erg/s/cm
in the soft and hard bands, respectively. We conclude that, in order to match
the depth of the CDFS exploiting massive clusters as cosmic telescopes, the
required number of cluster fields is about two orders of magnitude larger than
that offered by the 20 years Chandra archive. A significant step forward will
be made when future X-ray facilities, with ~1' angular resolution and large
effective area, will allow the serendipitous discovery of rare, strongly lensed
high- X-ray sources, enabling the study of faint AGN activity in early
Universe and the measurement of gravitational time delays in the X-ray
variability of multiply imaged AGN.Comment: Accepted for publication in A&
Noble Metal Nanoparticles Networks Stabilized by Rod‐Like Organometallic Bifunctional Thiols
od-like organometallic dithiol containing square-planar Pt(II) centers, i. e., trans,trans- [(H3COCS)Pt(PBu3)2(C�C C6H4 C6H4 C�C)(PBu3)2Pt(SCOCH3)] was used as bifunctional stabilizing agent for the synthesis of Pd-, Au-, and AgNPs (MNPs). All the MNPs showed diameters of about 4 nm, which can be controlled by carefully modulating the synthesis parameters. Covalent MNPs stabilization occurred through a single S bridge between Pt(II) and the noble metal nanocluster surfaces, leading to a network of regularly spaced NPs with the formation of dyads, as supported by SR-XPS data
and by TEM imaging analysis. The chemical nature of NPs systems was also confirmed by EDS and NMR. Comparison between SR-XPS data of MNPs and self-assembled monolayers and multilayers of pristine rod-like dithiols deposited onto polycrystalline gold surfaces revealed an electronic interaction between Pt(II) centers and biphenyl moieties of adjacent ligands, stabilizing the organic structure of the network. The possibility to obtain networks of regularly spaced MNPs opens outstanding perspectives in optoelectronics
Right ventricular failure in left heart disease: from pathophysiology to clinical manifestations and prognosis
Right heart failure (RHF) is a clinical syndrome in which symptoms and signs are caused by dysfunction and/or overload of the right heart structures, predominantly the right ventricle (RV), resulting in systemic venous hypertension, peripheral oedema and finally, the impaired ability of the right heart to provide tissue perfusion. Pathogenesis of RHF includes the incompetence of the right heart to maintain systemic venous pressure sufficiently low to guarantee an optimal venous return and to preserve renal function. Virtually, all myocardial diseases involving the left heart may be responsible for RHF. This may result from coronary artery disease, hypertension, valvular heart disease, cardiomyopathies and myocarditis. The most prominent clinical signs of RHF comprise swelling of the neck veins with an elevation of jugular venous pressure and ankle oedema. As the situation worsens, fluid accumulation becomes generalised with extensive oedema of the legs, congestive hepatomegaly and eventually ascites. Diagnosis of RHF requires the presence of signs of elevated right atrial and venous pressures, including dilation of neck veins, with at least one of the following criteria: (1) compromised RV function; (2) pulmonary hypertension; (3) peripheral oedema and congestive hepatomegaly. Early recognition of RHF and identifying the underlying aetiology as well as triggering factors are crucial to treating patients and possibly reversing the clinical manifestations effectively and improving prognosis
The effects of baicalein and baicalin on mitochondrial function and dynamics: A review
Mitochondria play an essential role in cell survival by providing energy, calcium buffering, and regulating apoptosis. A growing body of evidence shows that mitochondrial dysfunction and its consequences, including impairment of the mitochondrial respiratory chain, excessive generation of reactive oxygen species, and excitotoxicity, play a pivotal role in the pathogenesis of different diseases such as neurodegenerative diseases, neuropsychiatric disorders, and cancer. The therapeutical role of flavonoids on these diseases is gaining increasing acceptance. Numerous studies on experimental models have revealed the favorable role of flavonoids on mitochondrial function and structure. This review highlights the promising role of baicalin and its aglycone form, baicalein, on mitochondrial function and structure with a focus on its therapeutic effects. We also discuss their chemistry, sources and bioavailability
The luminosity function of galaxies to in clusters
We present deep composite luminosity functions in , , , , and
for six clusters at observed with the Hubble Space
Telescope Advanced Camera for Surveys. The luminosity functions reach to
absolute magnitude of mag. and are well fitted by a single
Schechter function with
mag. and (in all bands). The observations suggest that the
galaxy luminosity function is dominated by objects on the red sequence to at
least 6 mags. below the point. Comparison with local data shows that the
red sequence is well established at least at down to of the luminosity of the Milky Way and that galaxies down to the
regime of dwarf spheroidals have been completely assembled in clusters at this
redshift. We do not detect a steepening of the luminosity function at
as is observed locally. If the faint end upturn is real, the steepening of the
luminosity function must be due to a newly infalling population of faint dwarf
galaxies.Comment: Accepted by AJ. Only a selection of figures shown in paper: extra
figures to be made available on the AJ web site. Email R. De Propris for them
in the meantime. Fig. 1 could not be compressed to arXiv size limits. See
note in caption for how to obtain i
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