We present evidence for the discovery of a protocluster of starburst galaxies (Ly emitters, or LAEs) near the end of the epoch of reionization. The recent trend in the search for high-redshift ...protoclusters focuses on utilizing bias tracers, such as luminous starburst galaxies, as signposts of overdensities. Thus, we conducted a photometric selection of LAE candidates around a pair of spatially close, luminous LAEs at z = 6.5 in the Subaru/XMM-Newton Deep Survey field, using OSIRIS in its imaging mode at the 10.4 m Gran Telescopio Canarias in La Palma, Spain. The spectroscopic follow-up was done with OSIRIS in its multiobject spectroscopy capability. We have spectroscopically confirmed 10 LAEs via their recognizable Ly emission feature. The redshifts of these LAEs shed light on their 3D distributions within the observing window defined by the photometric selection. We have derived the galaxy number density contrast of δ gal = 3.18 − 1.99 + 3.47 , which led to the expected mass of the overdensity of 8.40 − 1.39 + 2.98 × 10 14 M . We also found evidence for the presence of a virialized core with M 200 = 4.06 − 1.90 + 2.77 × 10 13 M within this overdensity. Based on the extended Press-Schechter formalism, this overdensity would continue to grow in the linear regime and collapse to form a galaxy cluster at z coll = 0.84 − 0.43 + 0.57 . By the time this protocluster reaches z = 0, it will be a massive cluster of galaxies with mass 1.54 − 0.69 + 1.12 × 10 15 M , comparable to the Coma cluster. Thus, our careful analysis has pointed to evidence that this protocluster would evolve into a Coma-analog cluster in the present-day universe.
We study the galaxy stellar mass function in different environments in the local Universe, considering both the total mass function and that of individual galaxy morphological types. We compare the ...mass functions of galaxies with log10
M
*/M ≥ 10.25 in the general field and in galaxy groups, binary and single galaxy systems from the Padova-Millennium Galaxy and Group Catalogue at z = 0.04-0.1 with the mass function of galaxy clusters of the WIde-field Nearby Galaxy-Cluster Survey at z = 0.04-0.07. Strikingly, the variations of the mass function with global environment, overall, are small and subtle. The shapes of the mass functions of the general field and clusters are indistinguishable, and only small, statistically insignificant variations are allowed in groups. Only the mass function of our single galaxies, representing the least massive haloes and comprising less than a third of the general field population, is proportionally richer in low-mass galaxies than other environments. The most notable environmental effect is a progressive change in the upper galaxy mass, with very massive galaxies found only in the most massive environments. This environment-dependent mass cut-off is unable to affect the Schechter parameters and the Kolmogorov-Smirnov test, and can only be revealed by an ad hoc analysis. Finally, we show how, in each given environment, the mass function changes with morphological type, and that galaxies of the same morphological type can have different mass functions in different environments.
We present a comparison between the observed galaxy stellar mass function and the one predicted from the De Lucia & Blaizot semi-analytic model applied to the Millennium Simulation, for cluster ...satellites and galaxies in the field (meant as a wide portion of the sky, including all environments), in the local universe (z ~ 0.06), and at intermediate redshift (z ~ 0.6), with the aim to shed light on the processes which regulate the mass distribution in different environments. Our results point out two shortcomings of the model: an incorrect treatment of cluster-specific environmental effects and an overefficient galaxy formation at early times (as already found by, e.g., Weinmann et al.). Next, we consider only simulations. Mass functions obtained from the two prescriptions are different, however, results are qualitatively similar, indicating that the adopted methods to model the evolution of central and satellite galaxies still have to be better implemented in semi-analytic models.
Exploiting the capabilities of four different surveys - the Padova-Millennium Galaxy and Group Catalogue (PM2GC), the WIde-field Nearby Galaxy-cluster Survey (WINGS), the IMACS (Inamori-Magellan ...Areal Camera and Spectrograph) Cluster Building Survey (ICBS) and the ESO (European Southern Observatory) Distant Cluster Survey (EDisCS) - we analyse the galaxy stellar mass distribution as a function of local density in mass-limited samples, in the field and in clusters from low (
) to high (
) redshift. We find that at all redshifts and in all environments, local density plays a role in shaping the mass distribution. In the field, it regulates the shape of the mass function at any mass above the mass limits. In clusters, it seems to be important only at low masses (
in WINGS and
in EDisCS), otherwise it seems not to influence the mass distribution. Putting together our results with those of Calvi et al. and Vulcani et al. for the global environment, we argue that at least at
local density is more important than global environment in determining the galaxy stellar mass distribution, suggesting that galaxy properties are not much dependent on halo mass, but do depend on local scale processes.
Background
Coronavirus disease 2019 acute respiratory distress syndrome (COVID‐19 ARDS) is a disease that often requires invasive ventilation. Little is known about COVID‐19 ARDS sequelae. We ...assessed the mid‐term lung status of COVID‐19 survivors and investigated factors associated with pulmonary sequelae.
Methods
All adult COVID‐19 patients admitted to the intensive care unit from 25th February to 27th April 2020 were included. Lung function was evaluated through chest CT scan and pulmonary function tests (PFT). Logistic regression was used to identify predictors of persisting lung alterations.
Results
Forty‐nine patients (75%) completed lung assessment. Chest CT scan was performed after a median (interquartile range) time of 97 (89–105) days, whilst PFT after 142 (133–160) days. The median age was 58 (52–65) years and most patients were male (90%). The median duration of mechanical ventilation was 11 (6–16) days. Median tidal volume/ideal body weight (TV/IBW) was 6.8 (5.71–7.67) ml/Kg. 59% and 63% of patients showed radiological and functional lung sequelae, respectively. The diffusion capacity of carbon monoxide (DLCO) was reduced by 59%, with a median per cent of predicted DLCO of 72.1 (57.9–93.9) %. Mean TV/IBW during invasive ventilation emerged as an independent predictor of persistent CT scan abnormalities, whilst the duration of mechanical ventilation was an independent predictor of both CT and PFT abnormalities. The extension of lung involvement at hospital admission (evaluated through Radiographic Assessment of Lung Edema, RALE score) independently predicted the risk of persistent alterations in PFTs.
Conclusions
Both the extent of lung parenchymal involvement and mechanical ventilation protocols predict morphological and functional lung abnormalities months after COVID‐19.
Brain injury and cerebral vasospasm during the 14 days after the subarachnoid hemorrhage (SAH) are considered the leading causes of poor outcomes. The primary injury induces a cascade of events, ...including increased intracranial pressure, cerebral vasospasm and ischemia, glutamate excitotoxicity, and neuronal cell death. The objective of this study was to monitor the time course of glutamate, and associated enzymes, such as glutamate-oxaloacetate transaminase (GOT1), glutamate-pyruvate transaminase (GPT) in cerebrospinal fluid (CSF) and serum, shortly after SAH, and to assess their prognostic value. A total of 74 participants participated in this study: 45 participants with SAH and 29 controls. Serum and CSF were sampled up to 14 days after SAH. SAH participants' clinical and neurological status were assessed at hospitalization, at discharge from the hospital, and 3 months after SAH. Furthermore, a logistic regression analysis was carried out to evaluate the ability of GOT1 and glutamate levels to predict neurological outcomes. Our results demonstrated consistently elevated serum and CSF glutamate levels after SAH. Furthermore, serum glutamate level was significantly higher in patients with cerebral ischemia and poor neurological outcome. CSF GOT1 was significantly higher in patients with uncontrolled intracranial hypertension and cerebral ischemia post-SAH, and independently predicted poor neurological outcomes.
There is controversy in the literature regarding whether distant, massive, and dusty starbursts selected at (sub)millimeter wavelengths can trace galaxy overdensities. We thus performed the first ...systematic search for distant protoclusters around a homogeneously selected sample of 12 spectroscopically confirmed submillimeter galaxies (SMGs) at
z
∼ 1.2 − 5.3, which we selected from the GOODS-N field. We applied the well-established Poisson probability method (PPM) to search for megaparsec-scale overdensities around these SMGs, using three different photometric redshift catalogs. We robustly detect galaxy overdensities for 11 out of the 12 SMGs (i.e., 92%±8%), distributed over eight large-scale protoclusters. We confirm all three previously discovered protoclusters, and we detect five new ones around the SMGs SMM J123634 (
z
= 1.225), ID.19 (
z
= 2.047), SMM J123607 (
z
= 2.487), SMM J123606 (
z
= 2.505), and GN10 (
z
= 5.303). A wavelet-based analysis of the protocluster fields shows that the SMGs are located in protocluster cores with a complex morphology (compact, filamentary, or clumpy) and an average size of ∼(0.4 − 1) Mpc. By comparing the PPM results obtained using the three redshift catalogs independently, each of which trace different galaxy populations and redshift ranges, we speculate that we are possibly witnessing a transitioning phase at
z
≳ 4 for the galaxy population of protoclusters. While
z
≲ 4 protoclusters appear to be populated by dusty galaxies, those at the highest redshifts,
z
∼ 5, are detected as overdensities of Lyman
α
emitters or Lyman break galaxies. Further investigation with larger samples is required to reach a definitive conclusion. We also find a good correlation between the molecular (H
2
) gas mass of the SMGs and the significance of the associated overdensity. To explain the overall phenomenology, we suggest that galaxy interactions in dense environments likely triggered the starburst and gas-rich phase of the SMGs. Altogether, our findings support the scenario that SMGs are excellent tracers of distant protoclusters. The ones presented in this work are excellent targets for the
James Webb
Space Telescope. Similarly, future surveys with forthcoming facilities (e.g.,
Euclid
and LSST) can be tuned to detect even larger samples of distant protoclusters.
To determine whether Macklin effect (a linear collection of air contiguous to the bronchovascular sheath) on baseline CT imaging is an accurate predictor for subsequent pneumomediastinum ...(PMD)/pneumothorax (PNX) development in invasively ventilated patients with COVID-19-related acute respiratory distress syndrome (ARDS).
This is an observational, case-control study. From a prospectively acquired database, all consecutive invasively ventilated COVID-19 ARDS patients who underwent at least one baseline chest CT scan during the study time period (February 25th, 2020–December 31st, 2020) were identified; those who had tracheal lesion or already had PMD/PNX at the time of the first available chest imaging were excluded.
37/173 (21.4%) patients enrolled had PMD/PNX; specifically, 20 (11.5%) had PMD, 10 (5.8%) PNX, 7 (4%) both. 33/37 patients with subsequent PMD/PNX had Macklin effect on baseline CT (89.2%, true positives) 8.5 days range, 1–18 before the first actual radiological evidence of PMD/PNX. Conversely, 6/136 patients without PMD/PNX (4.4%, false positives) demonstrated Macklin effect (p < 0.001). Macklin effect yielded a sensitivity of 89.2% (95% confidence interval CI: 74.6–96.9), a specificity of 95.6% (95% CI: 90.6–98.4), a positive predictive value (PV) of 84.5% (95% CI: 71.3–92.3), a negative PV of 97.1% (95% CI: 74.6–96.9) and an accuracy of 94.2% (95% CI: 89.6–97.2) in predicting PMD/PNX (AUC:0.924).
Macklin effect accurately predicts, 8.5 days in advance, PMD/PNX development in COVID-19 ARDS patients.
•Macklin effect can be regarded as an early detector of lung frailty.•Macklin effect accurately predicts barotrauma in COVID-19 ARDS patients.•Median delay between Macklin effect first evidence and barotrauma onset was 8.5 days.•Patients with Macklin effect might benefit from ultraprotective ventilation strategy.
Abstract Study Objective To assess the safety of mechanical ventilation and effectiveness of extrinsic positive end-expiratory pressure (PEEP) (PEEPe ) in improving peripheral oxygen saturation (SpO2 ...) during direct microlaryngeal laser surgery; to assess the incidence, amount, and nature (dynamic hyperinflation or airflow obstruction) of ensuing intrinsic PEEP (PEEPi ); and to find a surrogate PEEPi indicator. Design Quasiexperimental. Setting S. Raffaele Hospital (Milano), November 2009 to December 2010. Patients Fifty-two adults scheduled for direct microlaryngeal laser surgery. Exclusion criterion is pregnancy. Interventions Twenty-one percent O2 mechanical ventilation through 4.5- to 5.5-mm internal diameter endotracheal tubes; in 29 patients, after measurement of PEEPi , an identical amount of PEEPe was added; and PEEPi. Measurements SpO2 , peak (Pawpeak ) and plateau (Pawplateau ) airway pressure, and end-expiratory carbon dioxide were measured every 5 minutes. Respiratory compliance (Crs ) was computed. PEEPi was measured (end-expiratory occlusion method). Main Results PEEPi ≥ 5 cm H2 O occurred in 14 patients (27%) after intubation, in 16 (30%) at the beginning, and in 14 (27.3%) at the end of surgery. Thirty-one patients (59.4%) exhibited PEEPi ≥ 5 cm H2 O on at least 1 time point. PEEPi at the beginning of surgery was positively correlated with Pawplateau , Crs , tidal volume, and body mass index. Body mass index was the only predictor for the occurrence of PEEPi ≥ 5 cm H2 O. At the beginning of surgery, the Pawplateau receiver operating characteristic curve predicting PEEPi ≥ 5 cm H2 O had area under the receiver operating characteristic curve of 0.85; best cutoff value of 15.5 cm H2 O (sensitivity, 88.9%; specificity, 75%; correctly classified cases, 86.1%). When PEEPe was applied, in 23 cases (82.1%), total PEEP equaled PEEPe + PEEPi ; in 3 (10.7%), it was lower; and in 2 (7.1%), it was higher. Application of PEEPe increased SpO2 ( P < .05) and Crs ( P < .05). Conclusions During ventilation through small endotracheal tubes, PEEPi (mostly due to dynamic hyperinflation) is common. Hemodynamic complications, barotrauma, and O2 desaturation (reversible with PEEPe ) are rare. Pawplateau provided by ventilators is useful in suspecting and monitoring the occurrence of PEEPi and allows detection of lung overdistension as PEEPe is applied.
•To assess safety and feasibility of LD in 24 poor grade aneurysmal SAH patients.•Ventriculo-lumbar pressure gradient lower than 6 mmHg is safe to start LD use.•VLPG monitoring plays a key role in ...avoiding potentially severe complications.•The use of LD with EVD results safe and feasible in the poor grade aSAH population.
The use of lumbar drain (LD) in the aneurysmal subarachnoid hemorrhage (aSAH) has been described to reduce cerebral vasospasm and delayed cerebral ischemia (DCI), with a lack of studies referring to high grade population. The purpose of our study is to assess safety and feasibility of LD in the poor grade aSAH population subjected to endovascular aneurysm occlusion.
Twenty-four consecutive poor grade aSAH patients, defined as grade IV and V according to World Federation of Neurological Surgeons (WFNS) classification, subjected to endovascular aneurysm occlusion, were retrospectively reviewed. Details of CSF drainage via LD and related complications were analyzed. Ventriculo-lumbar pressure gradient (VLPG) lower than 6 mmHg was considered in order to start LD use. Good outcome was defined as modified Rankin Scale (mRS) 0–2.
LD was started within 72 h since aSAH in 17 cases (70.8%), and in 7 cases (29.2%) it was delayed due to contraindications. The mean LD length was of 13.8 days. The median VLPG during drainage was 2 mmHg (IQR: 0–4). No cases of brain or spinal hemorrhage, permanent neurological worsening due to brain herniation were noted. Three cases (12.5%) of CSF infection and a related death (4.2%) were reported.
The use of LD, in association with external ventricular drain (EVD), seems to be safe and feasible in the poor grade aSAH population. VLPG monitoring seems to play a key role in avoiding potentially severe complications.
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