To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Background: Healthcare facilities have experienced many challenges during the COVID-19 pandemic, including limited personal protective equipment (PPE) supplies. Healthcare personnel (HCP) rely on PPE, vaccines, and other infection control measures to prevent SARS-CoV-2 infections. We describe PPE concerns reported by HCP who had close contact with COVID-19 patients in the workplace and tested positive for SARS-CoV-2. Method: The CDC collaborated with Emerging Infections Program (EIP) sites in 10 states to conduct surveillance for SARS-CoV-2 infections in HCP. EIP staff interviewed HCP with positive SARS-CoV-2 viral tests (ie, cases) to collect data on demographics, healthcare roles, exposures, PPE use, and concerns about their PPE use during COVID-19 patient care in the 14 days before the HCP’s SARS-CoV-2 positive test. PPE concerns were qualitatively coded as being related to supply (eg, low quality, shortages); use (eg, extended use, reuse, lack of fit test); or facility policy (eg, lack of guidance). We calculated and compared the percentages of cases reporting each concern type during the initial phase of the pandemic (April–May 2020), during the first US peak of daily COVID-19 cases (June–August 2020), and during the second US peak (September 2020–January 2021). We compared percentages using mid-P or Fisher exact tests (α = 0.05). Results: Among 1,998 HCP cases occurring during April 2020–January 2021 who had close contact with COVID-19 patients, 613 (30.7%) reported ≥1 PPE concern (Table 1). The percentage of cases reporting supply or use concerns was higher during the first peak period than the second peak period (supply concerns: 12.5% vs 7.5%; use concerns: 25.5% vs 18.2%; p Conclusions: Although lower percentages of HCP cases overall reported PPE concerns after the first US peak, our results highlight the importance of developing capacity to produce and distribute PPE during times of increased demand. The difference we observed among selected groups of cases may indicate that PPE access and use were more challenging for some, such as nonphysicians and nursing home HCP. These findings underscore the need to ensure that PPE is accessible and used correctly by HCP for whom use is recommended.
From 2014 to 2020, we compiled radiocarbon ages from the lower 48 states, creating a database of more than 100,000 archaeological, geological, and paleontological ages that will be freely available to researchers through the Canadian Archaeological Radiocarbon Database. Here, we discuss the process used to compile ages, general characteristics of the database, and lessons learned from this exercise in “big data” compilation.
Dust Cave (1Lu496) is a habitation site in a karstic vestibule in the middle Tennessee River Valley of Northern Alabama. The cave, periodically occupied over 7,000 years, contains well-preserved bone and botanical materials and exhibits microstratigraphy and intact occupation surfaces. The chronostratigraphic framework for Dust Cave is based on 43 14C dates, temporally diagnostic artifacts, and detailed geoarchaeological analysis. In a broad sense, five cultural components are defined and designated: Quad/Beaver Lake/Dalton (10,650–9200 cal B.C.), Early Side-Notched (10,000–9000 cal B.C.), Kirk Stemmed (8200–5800 cal B.C.), Eva/Morrow Mountain (6400 to 4000 cal B.C.), and Benton (4500–3600 cal B.C.). Microstratigraphic and artifact analyses indicate that the primary differences in the deposits over time relate to intensity of activity and spatial organization with regard to changing conditions in the cave, not to the types of activities. Geomorphic transformations influenced the timing of occupation at Dust Cave, especially the initial occupation. The chronostratigraphy provides a framework for assessing the stratigraphic separation of Dalton and Early Side-Notched materials, the shift in technology from blades to bifacial tools, and the context of detailed flora and fauna evidence. These remains provide unique insights into forager adaptations in the Midsouth from the end of the Pleistocene through the first half of the Holocene.
The multiphase electrodispersion precipitation of zirconia powders has been
done in the electric dispersion reactor (EDR). This paper presents the first
results obtained where the bench-scale EDR unit was operated in the
continuous mode to synthesize 130 ± 2 g of ZrO2 powder in
approximately 12 h. An aqueous solution of zirconyl nitrate was dispersed
and precipitated in a 2-ethyl-l-hexanol continuous phase containing 0.012
M to 0.12 M ammonia. A
gravity settler was used to remove soft agglomerates of the ZrO2
particles from the organic solvent. Electric bed filtration was employed to
remove the fines from the solvent, which was then recycled.
The particle-size distribution was varied by changing the electric field
strength. At high field strengths (approximately 20 kV/cm), the particle
sizes ranged from approximately 0.1 to 5 μm. The dried powder had a
consistency of talcum powder. Microwave and conventional heating experiments
showed that the powders were sinterable. The BET surface area of the powders
ranged from approximately 20 to 90 m2/g.
Email your librarian or administrator to recommend adding this to your organisation's collection.