2,198 research outputs found
The Arctic polar vortex response to volcanic forcing of different strengths
Tropical volcanic eruptions injecting sulfur into the stratosphere are assumed to not only scatter radiation and cool Earth’s surface but also to alter atmospheric circulation, and in particular to strengthen the stratospheric polar vortex in boreal winter. The exact impact is difficult to estimate because of the small number of well observed eruptions and the high internal variability of the vortex. We use large (100 member) ensembles of simulations with an Earth system model for idealized volcanic aerosol distributions resulting from sulfur injections between 2.5 and 20 Tg. We suggest the existence of a threshold somewhere between 2.5 and 5 Tg(S) below which the vortex does not show a detectable response to the injection. This nonlinearity is introduced partly through the infrared aerosol optical density which increases much stronger than linear with increasing particle size occurring for increasing injection amount. Additionally, the dynamical mechanism causing the vortex strengthening seems not to set in for small aerosol loading. Furthermore, we add to the recent discussion concerning a possible downward propagation of the circulation response leading to a winter warming in Northern Eurasia. At latitudes northward of about 50°N our simulations do show such an average warming pattern that is statistically significant for injections of 10 Tg(S) or more
Vibrational Circular Dichroism of Thiolate-Protected Au<sub>25</sub> Clusters: Accurate Prediction of Spectra and Chirality Transfer within the Mixed Ligand Shell
Characteristics and outcome of patients with newly diagnosed advanced or metastatic lung cancer admitted to intensive care units (ICUs)
BACKGROUND: Although patients with advanced or metastatic lung cancer have poor prognosis, admission to the ICU for management of life-threatening complications has increased over the years. Patients with newly diagnosed lung cancer appear as good candidates for ICU admission, but more robust information to assist decisions is lacking. The aim of our study was to evaluate the prognosis of newly diagnosed unresectable lung cancer patients. METHODS: A retrospective multicentric study analyzed the outcome of patients admitted to the ICU with a newly diagnosed lung cancer (diagnosis within the month) between 2010 and 2013. RESULTS: Out of the 100 patients, 30 had small cell lung cancer (SCLC) and 70 had non-small cell lung cancer. (Thirty patients had already been treated with oncologic treatments.) Mechanical ventilation (MV) was performed for 81 patients. Seventeen patients received emergency chemotherapy during their ICU stay. ICU, hospital, 3- and 6-month mortality were, respectively, 47, 60, 67 and 71%. Hospital mortality was 60% when invasive MV was used alone, 71% when MV and vasopressors were needed and 83% when MV, vasopressors and hemodialysis were required. In multivariate analysis, hospital mortality was associated with metastatic disease (OR 4.22 [1.4-12.4]; p = 0.008), need for invasive MV (OR 4.20 [1.11-16.2]; p = 0.030), while chemotherapy in ICU was associated with survival (OR 0.23, [0.07-0.81]; p = 0.020). CONCLUSION: This study shows that ICU management can be appropriate for selected newly diagnosed patients with advanced lung cancer, and chemotherapy might improve outcome for patients with SCLC admitted for cancer-related complications. Nevertheless, tumors' characteristics, numbers and types of organ dysfunction should be taken into account in the decisional process before admitting these patients in ICU.Peer reviewe
Re-imagining human rights photography: Ariella Azoulays intervention
Gormley and Allan focus on several pertinent theoretical contributions made by Ariella Azoulay that invite a radical rethinking of familiar assumptions regarding human rights photography. Having established a conceptual basis, they proceed to analyse several examples of photojournalists attempting to ‘activate’ viewers by inviting them to co-create photographic narratives via methods of hypertext and online archival interaction, and of International Non Governmental Organisations (INGOs) working to create projects which ‘speak’ to viewers by involving the children they seek to represent in the production of photography. It is argued that in taking up Azoulay’s call to rethink public relationships to human rights imagery, these projects represent progressive steps towards addressing the multifarious inequalities at stake. At the same time, however, realising this potential depends on making good the promise of rendering visible the normative ideals of human rights
Organic Bulk Heterojunction Infrared Photodiodes for Imaging Out to 1300 nm
This work studies
organic bulk heterojunction photodiodes with
a wide spectral range capable of imaging out to 1.3 μm in the
shortwave infrared. Adjustment of the donor-to-acceptor (polymer:fullerene)
ratio shows how blend composition affects the density of states (DOS)
which connects materials composition and optoelectronic properties
and provides insight into features relevant to understanding dispersive
transport and recombination in the narrow bandgap devices. Capacitance
spectroscopy and transient photocurrent measurements indicate the
main recombination mechanisms arise from deep traps and poor extraction
from accumulated space charges. The amount of space charge is reduced
with a decreasing acceptor concentration; however, this reduction
is offset by an increasing trap DOS. A device with 1:3 donor-to-acceptor
ratio shows the lowest density of deep traps and the highest external
quantum efficiency among the different blend compositions. The organic
photodiodes are used to demonstrate a single-pixel imaging system
that leverages compressive sensing algorithms to enable image reconstruction
Admission of advanced lung cancer patients to intensive care unit: A retrospective study of 76 patients
<p>Abstract</p> <p>Background</p> <p>Criteria for admitting patients with incurable diseases to the medical intensive care unit (MICU) remain unclear and have ethical implications.</p> <p>Methods</p> <p>We retrospectively evaluated MICU outcomes and identified risk factors for MICU mortality in consecutive patients with advanced lung cancer admitted to two university-hospital MICUs in France between 1996 and 2006.</p> <p>Results</p> <p>Of 76 included patients, 49 had non-small cell lung cancer (stage IIIB n = 20; stage IV n = 29). In 60 patients, MICU admission was directly related to the lung cancer (complication of cancer management, n = 30; cancer progression, n = 14; and lung-cancer-induced diseases, n = 17). Mechanical ventilation was required during the MICU stay in 57 patients. Thirty-six (47.4%) patients died in the MICU. Three factors were independently associated with MICU mortality: use of vasoactive agents (odds ratio [OR] 6.81 95% confidence interval [95%CI] [1.77-26.26], p = 0.005), mechanical ventilation (OR 6.61 95%CI [1.44-30.5], p = 0.015) and thrombocytopenia (OR 5.13; 95%CI [1.17-22.5], p = 0.030). In contrast, mortality was lower in patients admitted for a complication of cancer management (OR 0.206; 95%CI [0.058-0.738], p = 0.015). Of the 27 patients who returned home, four received specific lung cancer treatment after the MICU stay.</p> <p>Conclusions</p> <p>Patients with acute complications of treatment for advanced lung cancer may benefit from MCIU admission. Further studies are necessary to assess outcomes such as quality of life after MICU discharge.</p
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