The Early Data Release of the Dark Energy Spectroscopic Instrument

\ua9 2024. The Author(s). Published by the American Astronomical Society. The Dark Energy Spectroscopic Instrument (DESI) completed its 5 month Survey Validation in 2021 May. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data products. In total, the public release includes good-quality spectral information from 466,447 objects targeted as part of the Milky Way Survey, 428,758 as part of the Bright Galaxy Survey, 227,318 as part of the Luminous Red Galaxy sample, 437,664 as part of the Emission Line Galaxy sample, and 76,079 as part of the Quasar sample. In addition, the release includes spectral information from 137,148 objects that expand the scope beyond the primary samples as part of a series of secondary programs. Here, we describe the spectral data, data quality, data products, Large-Scale Structure science catalogs, access to the data, and references that provide relevant background to using these spectra

Mortality and pulmonary complications in patients undergoing surgery with perioperative sars-cov-2 infection: An international cohort study

Background The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (740%) had emergency surgery and 280 (248%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (261%) patients. 30-day mortality was 238% (268 of 1128). Pulmonary complications occurred in 577 (512%) of 1128 patients; 30-day mortality in these patients was 380% (219 of 577), accounting for 817% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 175 [95% CI 128-240], p<00001), age 70 years or older versus younger than 70 years (230 [165-322], p<00001), American Society of Anesthesiologists grades 3-5 versus grades 1-2 (235 [157-353], p<00001), malignant versus benign or obstetric diagnosis (155 [101-239], p=0046), emergency versus elective surgery (167 [106-263], p=0026), and major versus minor surgery (152 [101-231], p=0047). Interpretation Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Crack propagation monitoring on bonded joints with novel carbon nanotube doped adhesive films

An investigation on fatigue crack propagation on bonded joints has been carried out. For that purpose, a novel carbon nanotube (CNT) doped adhesive film has been used, exploiting CNT exceptional electrical sensitivity for fatigue damage monitoring. Single lap shear fatigue tests have been conducted at 7 kN load and 10 Hz frequency while the electrical response of the joints has been measured by means of voltage acquisition. In addition, crack length has been also monitored by optical analysis using a microscope camera. A clear correlation between the electrical response and the crack length has been highlighted during fatigue tests. In particular, it is possible to distinguish three different regions: the first, with no crack initiation and, thus, a stable measured electrical resistance; the second, where crack initiation and a first propagation take place, characterized by a slight increase of the electrical resistance; the third, including the final propagation to failure, where a sharp increase of the electrical resistance is observed. Moreover, the number of cycles to failure is not affected negatively by the addition of CNTs. Thus, CNT doped adhesive film capability to detect crack initiation and propagation has been demonstrated, proving their huge potential for Structural Health Monitoring (SHM) purposes

Complex geometry strain sensors based on 3d printed nanocomposites: Spring, three-column device and footstep-sensing platform

Electromechanical sensing devices, based on resins doped with carbon nanotubes, were developed by digital light processing (DLP) 3D printing technology in order to increase design freedom and identify new future and innovative applications. The analysis of electromechanical properties was carried out on specific sensors manufactured by DLP 3D printing technology with complex geometries: a spring, a three-column device and a footstep-sensing platform based on the three-column device. All of them show a great sensitivity of the measured electrical resistance to the applied load and high cyclic reproducibility, demonstrating their versatility and applicability to be implemented in numerous items in our daily lives or in industrial devices. Different types of carbon nanotubes—single-walled, double-walled and multi-walled CNTs (SWCNTs, DWCNTs, MWCNTs)—were used to evaluate the effect of their morphology on electrical and electromechanical performance. SWCNT-and DWCNT-doped nanocomposites presented a higher Tg compared with MWCNT-doped nanocomposites due to a lower UV light shielding effect. This phenomenon also justifies the decrease of nanocomposite Tg with the increase of CNT content in every case. The electromechanical analysis reveals that SWCNT-and DWCNT-doped nanocomposites show a higher electromechanical performance than nanocomposites doped with MWCNTs, with a slight increment of strain sensitivity in tensile conditions, but also a significant strain sensitivity gain at bending conditions

Dual effect of temperature and strain on the electrical response of highly sensitive silicone elastomers doped with graphene nanoplatelets

The electrical response of graphene nanoplatelet (GNP) doped silicone elastomers (PDMS and Ecoflex) are studied under the influence of temperature, strain and both at the same time. First, temperature tests indicate a positive temperature coefficient behavior of nanocomposites over a range of −20 to 80 °C, due to higher phonon/charge scattering effects and the separation of GNP because of thermal expansion. Ecoflex sensors show higher temperature sensitivity due to their higher coefficient of thermal expansion. Second, strain tests at 20 °C reveal that nanocomposites based on PDMS promote a higher strain sensitivity due to better GNP distribution. Moreover, the optimized nanocomposites exhibit exceptional gauge factor at low strain levels (110 at 1 % and 20·104 at 7.5 %). Finally, the sensitivity of the nanocomposites to strain decreased with increasing temperature due to thermodynamic degradation of the interface between the GNP and the matrix. The prevalent contact mechanisms at higher GNP contents promote a lower reduction in temperature sensitivity when increasing the GNP content. The sensitivity of the nanocomposites to temperature and strain also decreased with the number of tensile cycling loads, particularly at higher temperatures. These findings are used to select the suitable nanocomposite for temperature, strain or dual temperature-strain sensor applications

A preliminary study on self sensing composite structures with carbon nanotubes

Dynamic measurements on carbon nanotube (CNT) multiscale glass fiber reinforced polymers (GFRPs) were performed to assess the usage of self-sensing composite structures in vibration environment. To achieve that purpose, a composite cantilever beam was tested in static and dynamic conditions. Applied strain was measured by means of strain gauges mounted on the tested specimen. Static measurements were performed to investigate linearity and repeatability of the CNT sample response. The dynamic behavior was evaluated with step sine excitation at different forcing frequencies. Preliminary results finally proved the validity and the applicability of carbon nanotubes composites to measure dynamic forcing and vibration