This article presents 16-52-GHz multiband transmit and receive phased arrays designed to support multistandard 5G communications. The 64-element arrays are built using <inline-formula> <tex-math ...notation="LaTeX">16\,\times \, 1 </tex-math></inline-formula> linear arrays, and each has four <inline-formula> <tex-math notation="LaTeX">4\,\times \, 1 </tex-math></inline-formula> beamformer chips on a six-layer printed circuit board (PCB) with a Wilkinson combiner/divider network and tapered slot antennas. The wideband beamformer chips are designed in a SiGe BiCMOS process and use the RF beamforming architecture. The arrays have ±60° scanning capability in the azimuth plane and ±30° in the elevation plane with low sidelobes. The 64-element Tx array achieves an effective isotropic radiated power (EIRP) of 50-51.7 and 47.6-49 dBm at <inline-formula> <tex-math notation="LaTeX">P_{\mathrm{ sat}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">P_{1\,{\mathrm{ dB}}} </tex-math></inline-formula>, respectively, at 24.5-48 GHz. The 5G-NR-compliant waveforms with 400 MHz and up to 256-quadrature amplitude modulation (QAM) are transmitted with <2.98% EVMrms and 34-36 dBm average EIRP. Single-carrier (SC) 400-MHz 64-QAM waveforms are also transmitted achieving <3% EVMrms with 39-40.3 dBm average EIRP and 2.4 Gb/s data rate. The 64-element Rx array achieves a system NF of 5.3-6.9 dB and a measured <inline-formula> <tex-math notation="LaTeX">G/T </tex-math></inline-formula> of −19.3 to −14.4 dB (with <inline-formula> <tex-math notation="LaTeX">{T} _{\mathrm{ ant}} = 295 </tex-math></inline-formula> K) at 20-50 GHz, and < 2.6% error vector magnitude (EVM) performance when tested with 400-MHz 256-QAM 5G-NR-complaint packets. To the author's knowledge, this work achieves the highest bandwidth Tx and Rx phased array systems suitable for multiband 5G operation.
The COVID-19 pandemic is an unprecedented global crisis. Many countries have implemented restrictions on population movement to slow the spread of severe acute respiratory syndrome coronavirus 2 and ...prevent health systems from becoming overwhelmed; some have instituted full or partial lockdowns. However, lockdowns and other extreme restrictions cannot be sustained for the long term in the hope that there will be an effective vaccine or treatment for COVID-19. Governments worldwide now face the common challenge of easing lockdowns and restrictions while balancing various health, social, and economic concerns. To facilitate cross-country learning, this Health Policy paper uses an adapted framework to examine the approaches taken by nine high-income countries and regions that have started to ease COVID-19 restrictions: five in the Asia Pacific region (ie, Hong Kong Special Administrative Region, Japan, New Zealand, Singapore, and South Korea) and four in Europe (ie, Germany, Norway, Spain, and the UK). This comparative analysis presents important lessons to be learnt from the experiences of these countries and regions. Although the future of the virus is unknown at present, countries should continue to share their experiences, shield populations who are at risk, and suppress transmission to save lives.
To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester ...formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l(-1)). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.
A novel coronavirus (2019-nCoV) causing severe acute respiratory disease emerged recently in Wuhan, China. Information on reported cases strongly indicates human-to-human spread, and the most recent ...information is increasingly indicative of sustained human-to-human transmission. While the overall severity profile among cases may change as more mild cases are identified, we estimate a risk of fatality among hospitalised cases at 14% (95% confidence interval: 3.9-32%).
Phosphorus and Life on a Water World Filippelli, Gabriel M.
Geophysical research letters,
16 April 2022, Letnik:
49, Številka:
7
Journal Article
Recenzirano
Odprti dostop
On Earth, the major mechanism for providing the vital limiting nutrient phosphorus necessary to fuel biological productivity and the long arc of evolution is weathering of exposed continental rocks. ...It has been presumed that life may not be present on exoplanets with substantially more water than Earth. Many of these “Water Worlds” exist, but without exposed land mass for weathering, there is not a viable mechanism for nutrient delivery and climate stabilization. In novel laboratory experiments performed in chambers designed to mimic the weathering of seafloor basalts in anoxic conditions, Syverson et al. (2021, https://doi.org/10.1029/2021GL094442) found that silicate weathering in these conditions release an adequate amount of phosphorus to fuel a robust biosphere, at least in an idealized system. Perhaps we shouldn't rule out “Water Worlds” as potential harbors for life after all?
Plain Language Summary
Based on chamber experiments, Syverson et al. (2021, https://doi.org/10.1029/2021GL094442) show that an adequate amount of phosphorus can be weathered rom seafloor basalts in anoxic settings to supply biological productivity and support a long‐lived ecosystem required for evolution on a water world.
Key Points
Many “water worlds” exist in the galaxy, but it has been presumed that they lack an adequate phosphorus supply to maintain life
To test this assumption, Syverson et al. (2021) performed anoxic chamber weathering experiments on basalts
Syverson et al. (2021) found significant phosphorus weathering occurs in this setting, and thus water worlds may sustain prolonged life
We used acoustic telemetry to describe the patterns of vertical movement, site fidelity and residency of grey reef sharks (Carcharhinus amblyrhynchos) on the outer slope of coral reefs in Palau, ...Micronesia, over a period of two years and nine months. We tagged 39 sharks (mostly adult females) of which 31 were detected regularly throughout the study. Sharks displayed strong inter-annual residency with greater attendance at monitored sites during summer than winter months. More individuals were detected during the day than at night. Mean depths of tagged sharks increased from 35 m in winter to 60 m in spring following an increase in water temperature at 60 m, with maximum mean depths attained when water temperatures at 60 m stabilised around 29°C. Sharks descended to greater depths and used a wider range of depths around the time of the full moon. There were also crepuscular cycles in mean depth, with sharks moving into shallower waters at dawn and dusk each day. We suggest that daily, lunar and seasonal cycles in vertical movement and residency are strategies for optimising both energetic budgets and foraging behaviour. Cyclical patterns of movement in response to environmental variables might affect the susceptibility of reef sharks to fishing, a consideration that should be taken into account in the implementation of conservation strategies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Digital proxies of human mobility and physical mixing have been used to monitor viral transmissibility and effectiveness of social distancing interventions in the ongoing COVID-19 pandemic. We ...develop a new framework that parameterizes disease transmission models with age-specific digital mobility data. By fitting the model to case data in Hong Kong, we are able to accurately track the local effective reproduction number of COVID-19 in near real time (i.e., no longer constrained by the delay of around 9 days between infection and reporting of cases) which is essential for quick assessment of the effectiveness of interventions on reducing transmissibility. Our findings show that accurate nowcast and forecast of COVID-19 epidemics can be obtained by integrating valid digital proxies of physical mixing into conventional epidemic models.
•COVID-19 is a viral disease caused by SARS-CoV-2.•Twenty-three autopsy cases demonstrate that COVID-19 is a systemic disease with major pulmonary and cardiac manifestations.•COVID-19 produces an ...acute interstitial pneumonia, usually with a prominent diffuse alveolar damage (DAD) component, often coupled with a thrombotic microangiopathy.•The heart frequently shows acute cardiomyocyte injury and, in some cases, pericarditis and/or myocarditis.•Patients with fatal COVID-19 frequently are obese and have pre-existing cardiac disease, hypertension and/or diabetes mellitus.
This paper collates the pathological findings from initial published autopsy reports on 23 patients with coronavirus disease 2019 (COVID-19) from 5 centers in the United States of America, including 3 cases from Houston, Texas. Findings confirm that COVID-19 is a systemic disease with major involvement of the lungs and heart. Acute COVID-19 pneumonia has features of a distinctive acute interstitial pneumonia with a diffuse alveolar damage component, coupled with microvascular involvement with intra- and extravascular fibrin deposition and intravascular trapping of neutrophils, and, frequently, with formation of microthombi in arterioles. Major pulmonary thromboemboli with pulmonary infarcts and/or hemorrhage occurred in 5 of the 23 patients. Two of the Houston cases had interstitial pneumonia with diffuse alveolar damage pattern. One of the Houston cases had multiple bilateral segmental pulmonary thromboemboli with infarcts and hemorrhages coupled with, in nonhemorrhagic areas, a distinctive interstitial lymphocytic pneumonitis with intra-alveolar fibrin deposits and no hyaline membranes, possibly representing a transition form to acute fibrinous and organizing pneumonia. Multifocal acute injury of cardiac myocytes was frequently observed. Lymphocytic myocarditis was reported in 1 case. In addition to major pulmonary pathology, the 3 Houston cases had evidence of lymphocytic pericarditis, multifocal acute injury of cardiomyocytes without inflammatory cellular infiltrates, depletion of splenic white pulp, focal hepatocellular degeneration and rare glomerular capillary thrombosis. Each had evidence of chronic cardiac disease: hypertensive left ventricular hypertrophy (420 g heart), dilated cardiomyopathy (1070 g heart), and hypertrophic cardiomyopathy (670 g heart). All 3 subjects were obese (BMIs of 33.8, 51.65, and 35.2 Kg/m2). Overall, the autopsy findings support the concept that the pathogenesis of severe COVID-19 disease involves direct viral-induced injury of multiple organs, including heart and lungs, coupled with the consequences of a procoagulant state with coagulopathy.
The west African Ebola epidemic that began in 2013 exposed deep inadequacies in the national and international institutions responsible for protecting the public from the far-reaching human, social, ...economic, and political consequences of infectious disease outbreaks. The Ebola epidemic raised a crucial question: what reforms are needed to mend the fragile global system for outbreak prevention and response, rebuild confidence, and prevent future disasters?
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