49 research outputs found
Galaxies in the central regions of simulated galaxy clusters
In this paper, we assess the impact of numerical resolution and of the
implementation of energy input from AGN feedback models on the inner structure
of cluster sub-haloes in hydrodynamic simulations. We compare several zoom-in
re-simulations of a sub-sample of the cluster-sized haloes studied in
Meneghetti et al. (2020), obtained by varying mass resolution, softening length
and AGN energy feedback scheme. We study the impact of these different setups
on the subhalo abundances, their radial distribution, their density and mass
profiles and the relation between the maximum circular velocity, which is a
proxy for subhalo compactness. Regardless of the adopted numerical resolution
and feedback model, subhaloes with masses Msub < 1e11Msun/h, the most relevant
mass-range for galaxy-galaxy strong lensing, have maximum circular velocities
~30% smaller than those measured from strong lensing observations of Bergamini
et al. (2019). We also find that simulations with less effective AGN energy
feedback produce massive subhaloes (Msub> 1e11 Msun/h ) with higher maximum
circular velocity and that their Vmax - Msub relation approaches the observed
one. However the stellar-mass number count of these objects exceeds the one
found in observations and we find that the compactness of these simulated
subhaloes is the result of an extremely over-efficient star formation in their
cores, also leading to larger-than-observed subhalo stellar mass. We conclude
that simulations are unable to simultaneously reproduce the observed stellar
masses and compactness (or maximum circular velocities) of cluster galaxies.
Thus, the discrepancy between theory and observations that emerged from the
analysis of Meneghetti et al. (2020) persists. It remains an open question as
to whether such a discrepancy reflects limitations of the current
implementation of galaxy formation models or the LCDM paradigm.Comment: 11 pages, 10 figures, abstract is redacted to fit arXiv character
count limi
The probability of galaxy-galaxy strong lensing events in hydrodynamical simulations of galaxy clusters
Meneghetti et al. (2020) recently reported an excess of galaxy-galaxy strong
lensing (GGSL) in galaxy clusters compared to expectations from the LCDM
cosmological model. Theoretical estimates of the GGSL probability are based on
the analysis of numerical hydrodynamical simulations in the LCDM cosmology. We
quantify the impact of the numerical resolution and AGN feedback scheme adopted
in cosmological simulations on the predicted GGSL probability and determine if
varying these simulation properties can alleviate the gap with observations. We
repeat the analysis of Meneghetti et al. (2020) on cluster-size halos simulated
with different mass and force resolutions and implementing several independent
AGN feedback schemes. We find that improving the mass resolution by a factor of
ten and twenty-five, while using the same galaxy formation model that includes
AGN feedback, does not affect the GGSL probability. We find similar results
regarding the choice of gravitational softening. On the contrary, adopting an
AGN feedback scheme that is less efficient at suppressing gas cooling and star
formation leads to an increase in the GGSL probability by a factor between
three and six. However, we notice that such simulations form overly massive
subhalos whose contribution to the lensing cross-section would be significant
while their Einstein radii are too large to be consistent with the
observations. The primary contributors to the observed GGSL cross-sections are
subhalos with smaller masses, that are compact enough to become critical for
lensing. The population with these required characteristics appears to be
absent in simulations.Comment: 13 pages, 11 figures. Submitted for publication on Astronomy and
Astrophysic
"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool
Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 ± 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys
Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy
IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical
attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced
colorectal cancers at diagnosis.
OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced
oncologic stage and change in clinical presentation for patients with colorectal cancer.
DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all
17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December
31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period),
in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was
30 days from surgery.
EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery,
palliative procedures, and atypical or segmental resections.
MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer
at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as
cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding,
lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery,
and palliative surgery. The independent association between the pandemic period and the outcomes
was assessed using multivariate random-effects logistic regression, with hospital as the cluster
variable.
RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years)
underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142
(56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was
significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR],
1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic
lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03).
CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the
SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients
undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for
these patients
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Detection of diversity and stand parameters in Mediterranean forests using leaf-off discrete return LiDAR data
A methodological approach based on detailed land-use map, high-resolution LiDAR data and field surveys was developed to categorize productive and non-productive mixed forests, both in term of stand attributes and struc- tural diversity. In 2011, leaf-off dedicated airborne LiDAR data were collected in a 20,000 ha inland patchy area which was representative of soil land use in the Apennines mountains of southern Italy. By combining field and LiDAR data in 5574 ha of forests with coexisting evergreen and deciduous species, we modelled common forest stand variables (height, diameter, volume and biomass) with high accuracy (0.60 ≤ Adj.R2 ≤ 0.89). Moreover, a moderate correlation (0.425 ≤ τ ≤ 0.462) between field- and LiDAR-derived diversity indices was found. About 3393 ha of forests are enclosed in protected areas of the Natura 2000 network, which in turn possesses 77% (~576,286 Mg) of total aboveground dry biomass. Overall, eight forest types were identified, one of which, the Eu- ropean beech, is only found in the Natura 2000 sites, while other forest types are also found elsewhere. This is the first study to undertake a LiDAR analysis of Mediterranean forests in the Campania Region and might help better evaluate trade-off, especially in protected areas, in order to enhance multiple benefits and support sustainable management of forests