74 research outputs found
Reconstructing the galaxy density field with photometric redshifts: II. Environment-dependent galaxy evolution since
Although extensively investigated, the role of the environment in galaxy
formation is still not well understood. In this context, the Galaxy Stellar
Mass Function (GSMF) is a powerful tool to understand how environment relates
to galaxy mass assembly and the quenching of star-formation. In this work, we
make use of the high-precision photometric redshifts of the UltraVISTA Survey
to study the GSMF in different environments up to , on physical
scales from 0.3 to 2 Mpc, down to masses of . We
witness the appearance of environmental signatures for both quiescent and
star-forming galaxies. We find that the shape of the GSMF of quiescent galaxies
is different in high- and low-density environments up to with the
high-mass end () being enhanced in high-density
environments. On the contrary, for star-forming galaxies a difference between
the GSMF in high- and low density environments is present for masses . Star-forming galaxies in this mass range appear to
be more frequent in low-density environments up to . Differences in
the shape of the GSMF are not visible anymore at . Our results, in terms
of general trends in the shape of the GSMF, are in agreement with a scenario in
which galaxies are quenched when they enter hot gas-dominated massive haloes
which are preferentially in high-density environments.Comment: 18 pages, 10 figures. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Novel Physical Vapor Deposition Approach to Hybrid Perovskites: Growth of MAPbI3 Thin Films by RF-Magnetron Sputtering
Solution-based methods represent the most widespread approach used to deposit
hybrid organic-inorganic perovskite films for low-cost but efficient solar
cells. However, solution-process techniques offer limited control over film
morphology and crystallinity, and most importantly do not allow sequential film
deposition to produce perovskite-perovskite heterostructures. Here the
successful deposition of CH3NH3PbI3 (MAPI) thin films by RF-magnetron
sputtering is reported, an industry-tested method to grow large area devices
with precisely controlled stoichiometry. MAPI films are grown starting from a
single-target made of CH3NH3I (MAI) and PbI2. Films are single-phase, with a
barely detectable content of unreacted PbI2, full surface coverage and
thickness ranging from less than 200 nm to more than 3 {\mu}m. Light absorption
and emission properties of the deposited films are comparable to as-grown
solution-processed MAPI films. The development of vapor-phase deposition
methods is of interest to advance perovskite photovoltaic devices with the
possibility of fabricating perovskite multijunction solar cells or multicolor
bright light-emitting devices in the whole visible spectrum
The Role of the Environment in Galaxy Evolution
Although the general picture of how galaxies have formed and evolved through cosmic time is already in place, still many details are missing. An example is represented by the role of environment in determining their observed properties. Local environment has been thoroughly explored through observations at low redshift and it has recently started to being investigated also in the distant Universe. Moreover, general attention has been increasingly focused on the cosmic web.
This work explores how environment is observationally related to galaxy properties such as their stellar mass, their star-formation activity, or the presence of AGN phenomena in a large redshift range (0.2 < z < 3). To perform this study, both spectroscopic redshift data sets as well as photometric redshift surveys have been deployed.
The picture that emerges is that high-density environments are favored places for galaxy evolution, showing an enhanced fraction of massive galaxies which have stopped forming stars. Galaxies in high-density environments have an increased probability of hosting radio-AGNs (belonging to the ensemble of processes that turn off the star-formation in massive galaxies) and these effects are visible since the start of the decline in the cosmic star-formation history. Large-scale structures, such as the filaments of the cosmic web, have also a role in shaping galaxy evolution and they may represent key places for the pre-processing of galaxies before they enter higher density regions such as the cluster or group environment.
As an increasing amount of observational evidence on the relation between the evolution of galaxies and their environment is gathered, a complete solution to the problem of how the local galaxy population has evolved approaches, and the history of galaxies from their formation at the dawn of time to the present day gets closer to being traced
Nature vs. Nurture: Revisiting the environmental impact on star formation activities of galaxies
We present a systematic study of the environmental impact on star formation
activities of galaxies using a mass-complete sample of 170k galaxies at
from the latest COSMOS2020 catalog. At , we find that the mean
star-formation rate (SFR) of all galaxies decreases with increasing density of
the environment. However when we consider only star-forming galaxies, the mean
SFR becomes independent of the environment at we observe a
clear positive correlation between the SFR and density of the environment for
all the galaxies. On the other hand, stellar mass of the galaxies increases
significantly with the environments at all redshifts except for star-forming
galaxies at . The fraction of quiescent galaxies increases with increasing
density of environment at , and the ``morphology-density'' relation is
confirmed to be present up to . We also find that environmental
quenching is negligible at , whereas mass quenching is the dominant
quenching mechanism for massive galaxies at all redshifts. Based on these
results, we argue that stellar mass regulated physical processes might be the
major driving force for star formation activities of galaxies. At low redshift
() massive galaxies are quenched primarily due to their high mass,
resulting in a normal ``SFR-density'' relation. At high redshift () most
of the galaxies are star-forming ones tightly following the star-forming main
sequence, and the difference in their stellar mass at different environments
naturally leads to a reversal of ``SFR-density'' relation.Comment: 16 pages, 7 figures, accepted for publication in Ap
Floating rafts as breeding habitats for the Common tern, Sterna hirundo. Colonization patterns, abundance and reproductive success in Venice Lagoon
The Venice lagoon hosts the 15% of the entire Italian breeding population of Common terns, Sterna hirundo, highlighting the great value of the area for this species. However, in the last 25 years, a substantial decline of Common terns has been detected in the Lagoon, which culminated in 2008. The main causes of this negative trend were the loss of salt marsh habitats, where terns typically breed in the Venice lagoon. This was due to the increase in the mean sea level and the greater frequency of high tides during the reproductive period with consequent flooding of their breeding sites; competition with yellowlegged gulls (Larus michahellis), predation and human disturbance. As a preliminary experimental approach to counter the depletion of the species and favour its recovery, we performed a habitat loss compensation project by setting up four floating rafts (3x2m), covered by two different types of substrate (sandy and vegetal substrate). This was to function as an artificial nesting site safe from flooding, positioned in a protected internal wetland area of the Venice lagoon, Valle Averto (Sourthern Lagoon). We studied the colonization patterns of the rafts and the reproductive success of Common tern breeding pairs during the 2014 and 2015 breeding seasons. We also investigated those environmental and structural variables that could favour the use of the rafts and the nesting success of the species. In both years, the rafts were successfully colonized and used by terns for nesting. Our results also indicated higher temperature, lower rainfall and greater distance from the shore as the main habitat factors favouring the occurrence and the reproductive success of the breeding pairs, while a windrow of dead plants was indicated as the preferred substrate for covering rafts in order to make them more attractive. The results provided some suggestions for successful restoration plans to be developed in similar lagoon areas
CD38: A Target for Immunotherapeutic Approaches in Multiple Myeloma
Multiple Myeloma (MM) is a hematological cancer characterized by proliferation of malignant plasma cells in the bone marrow (BM). MM represents the second most frequent hematological malignancy, accounting 1% of all cancer and 13% of hematological tumors, with ~9,000 new cases per year. Patients with monoclonal gammopathy of undetermined significance (MGUS) and asymptomatic smoldering MM (SMM) usually evolve to active MM in the presence of increased tumor burden, symptoms and organ damage. Despite the role of high dose chemotherapy in combination with autologous stem cell transplantation and the introduction of new treatments, the prognosis of MM patients is still poor, and novel therapeutic approaches have been tested in the last years, including new immunomodulatory drugs, proteasome inhibitors and monoclonal antibodies (mAbs). CD38 is a glycoprotein with ectoenzymatic functions, which is expressed on plasma cells and other lymphoid and myeloid cell populations. Since its expression is very high and uniform on myeloma cells, CD38 is a good target for novel therapeutic strategies. Among them, immunotherapy represents a promising approach. Here, we summarized recent findings regarding CD38-targeted immunotherapy of MM in pre-clinical models and clinical trials, including (i) mAbs (daratumumab and isatuximab), (ii) radioimmunotherapy, and (iii) adoptive cell therapy, using chimeric antigen receptor (CAR)-transfected T cells specific for CD38. Finally, we discussed the efficacy and possible limitations of these therapeutic approaches for MM patients
CD38 and bone marrow microenvironment.
This review summarizes the events ruled by CD38 shaping the bone marrow environment, recapitulating old and new aspects derived from the body of knowledge on the molecule. The disease models considered were myeloma and chronic lymphocytic leukemia (CLL). CD38 has been analyzed considering its twin function as receptor and enzyme, roles usually not considered in clinics, where it is used as a routine marker. Another aspect pertaining basic science concerns the role of the molecule as a member of an ectoenzyme network, potentially metabolizing soluble factors not yet analyzed (e.g., NAD+, ATP, NAM) or influencing hormone secretion (e.g., oxytocin). The last point is focused on the use of CD38 as a target of an antibody-mediated therapeutic approach in myeloma and CLL. A recent observation is that CD38 may run an escape circuit leading to the production of adenosine. The generation of local anergy may be blocked by using anti-CD38 antibodies. Consequently, not only might CD38 be a prime target for mAb-mediated therapy, but its functional block may contribute to general improvement in cancer immunotherapy and outcomes
Generation of potent neutralizing human monoclonal antibodies against cytomegalovirus infection from immune B cells
<p>Abstract</p> <p>Background</p> <p>Human monoclonal antibodies (mAbs) generated as a result of the immune response are likely to be the most effective therapeutic antibodies, particularly in the case of infectious diseases against which the immune response is protective.</p> <p>Human cytomegalovirus (HCMV) is an ubiquitous opportunistic virus that is the most serious pathogenic agent in transplant patients. The available therapeutic armamentarium (e.g. HCMV hyperimmune globulins or antivirals) is associated with severe side effects and the emergence of drug-resistant strains; therefore, neutralizing human mAb may be a decisive alternative in the prevention of primary and re-activated HCMV infections in these patients.</p> <p>Results</p> <p>The purpose of this study was to generate neutralizing mAb against HCMV from the immunological repertoire of immune donors. To this aim, we designed an efficient technology relying on two discrete and sequential steps: first, human B-lymphocytes are stimulated with TLR9-agonists and IL-2; second, after both additives are removed, the cells are infected with EBV. Using this strategy we obtained 29 clones secreting IgG neutralizing the HCMV infectivity; four among these were further characterized. All of the mAbs neutralize the infection in different combinations of HCMV strains and target cells, with a potency ~20 fold higher than that of the HCMV hyperimmune globulins, currently used in transplant recipients. Recombinant human monoclonal IgG1 suitable as a prophylactic or therapeutic tool in clinical applications has been generated.</p> <p>Conclusion</p> <p>The technology described has proven to be more reproducible, efficient and rapid than previously reported techniques, and can be adopted at low overall costs by any cell biology laboratory for the development of fully human mAbs for immunotherapeutic uses.</p
Distributed Computing and Storage Infrastructure for PUNCH4NFDI
The PUNCH4NFDI consortium brings together scientists from the German particle physics, hadron and nuclear physics, astronomy, and astro-particle physics communities to improve the management and (re-)use of scientific data from these interrelated communities. The PUNCH sciences have a long tradition of building large instruments that are planned, constructed and operated by international collaborations. While the large collaborations typically employ advanced tools for data management and distribution, smaller-scale experiments often suffer from very limited resources to address these aspects. One of the aims of the consortium is to evaluate and enable or adopt existing solutions. Instances of a prototype federated and distributed computing and storage infrastructure have been set up at a handful of sites in Germany. This prototype is used to gain experience in running of scientific workflows to further guide the development of the Science Data Platform, which is an overarching goal of the consortium
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