In this article we present the development of a set of opto-mechanical components (a kinematic mount, a translation stage and an integrating sphere) that can be easily built using a 3D printer based ...on Fused Filament Fabrication (FFF) and parts that can be found in any hardware store. Here we provide a brief description of the 3D models used and some details on the fabrication process. Moreover, with the help of three simple experimental setups, we evaluate the performance of the opto-mechanical components developed by doing a quantitative comparison with its commercial counterparts. Our results indicate that the components fabricated are highly customizable, low-cost, require a short time to be fabricated and surprisingly, offer a performance that compares favorably with respect to low-end commercial alternatives.
We demonstrate a simple, flexible and cost-effective system to automatize most of the kinematic mounts available nowadays on the market. It combines 3D-printed components, an Arduino board, stepper ...motors and simple electronics. The developed system can control up to ten stepper motors independently and simultaneously using commands sent through the serial port, and it is suitable for applications where optical realignment using flat mirrors is required on a periodic basis.
Weak value amplification (WVA) is a concept that has been extensively used in a myriad of applications with the aim of rendering measurable tiny changes of a variable of interest. In spite of this, ...there is still an on-going debate about its true nature and whether is really needed for achieving high sensitivity. Here we aim at helping to clarify the puzzle, using a specific example and some basic concepts from quantum estimation theory, highlighting what the use of the WVA concept can offer and what it can not. While WVA cannot be used to go beyond some fundamental sensitivity limits that arise from considering the full nature of the quantum states, WVA can notwithstanding enhance the sensitivity of real and specific detection schemes that are limited by many other things apart from the quantum nature of the states involved, i.e. technical noise. Importantly, it can do that in a straightforward and easily accessible manner.
A variety of bacterial and fungal co-infections may be attributed to the coronavirus disease 2019 (COVID-19), particularly in people who already have a medical condition such diabetes mellitus or ...those who received large dosages of steroids.
We described a 52-year-old diabetic man who was receiving high doses of dexamethasone and antibiotics while receiving ambulatory care for COVID-19 pneumonia. His anterior rhinoscopy revealed a necrotic scab, and a sample confirmed Mucor spp. He underwent surgery and was given amphotericin as a result of the severity of the condition, palpebral ptosis, and right ocular palsy he was experiencing. The patien ́s progression was satisfactory.
pre-existing diabetes mellitus, previous steroid and antimicrobial use, as well as SARS-CoV-2 infection are some of the risk factors associated with Mucor spp. infection. Prompt detection of mucormycosis is important in the management of these affected patients.
The use of unmanned aerial vehicles (UAV) for forest monitoring has grown significantly in recent years, providing information with high spatial resolution and temporal versatility. UAV with ...multispectral sensors allow the use of indexes such as the normalized difference vegetation index (NDVI), which determines the vigor, physiological stress and photosynthetic activity of vegetation. This study aimed to analyze the spectral responses and variations of NDVI in tree crowns, as well as their correlation with climatic factors over the course of one year. The study area encompassed a 1.6-ha site in Durango, Mexico, where
Pinus cembroides
,
Pinus engelmannii
, and
Quercus grisea
coexist. Multispectral images were acquired with UAV and information on meteorological variables was obtained from NASA/POWER database. An ANOVA explored possible differences in NDVI among the three species. Pearson correlation was performed to identify the linear relationship between NDVI and meteorological variables. Significant differences in NDVI values were found at the genus level (
Pinus
and
Quercus
), possibly related to the physiological features of the species and their phenology.
Quercus grisea
had the lowest NDVI values throughout the year which may be attributed to its sensitivity to relative humidity and temperatures. Although the use of UAV with a multispectral sensor for NDVI monitoring allowed genera differentiation, in more complex forest analyses hyperspectral and LiDAR sensors should be integrated, as well other vegetation indexes be considered.
QGIS is the most popular free geospatial software in the world. QGIS belongs to the Open-Source Geospatial Foundation (OSGeo). Among the main strengths of this Geographic Information Systems are: the ...incorporation of tools via plugins, and a community of users and developers in constant growth. Despite the importance on the use of QGIS on the scientific community, to date there are no systematic studies indicating how the acceptance of this software has evolved through time. Therefore, the objective of this research was to characterize the scientific production and extent where QGIS has been used as their main geospatial tool. We conducted a bibliometric analysis of documents published in Scopus from 2005 to 2020 (931 manuscripts). The annual rate of publications increase was 40.3%. We found strong and positive correlations regarding the number of contributing code programmers (r=0.66, p<0.005); and the total income of the QGIS project (r=0.88, p<0.001). Seventy-two percent of the publications were included in six fields of study, being Earth and Planetary Sciences the most representative. Italy was the country with larger scientific production, while the USA was the most influential country (being the first, regarding the number of citations). In terms of the countries, the larger number of papers found were from Portugal, Italy, Brazil, and France. The International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences - ISPRS Archives stands among journals with the largest number of publications (47). In terms of collaborative networks among countries, we found strong links between authors from Germany, Switzerland, Greece, and Spain. Author network analysis showed three solid networks in different fields of study. We observed a favorable trend in the acceptance of QGIS across the world and a widespread development of collaborative networks. The present paper allowed increase the knowledge of geographic information systems, especially the development of scientific production using QGIS.
Sample pooling for SARS-CoV-2 RT-PCR screening de Salazar, Adolfo; Aguilera, Antonio; Trastoy, Rocio ...
Clinical microbiology and infection,
12/2020, Letnik:
26, Številka:
12
Journal Article
Recenzirano
Odprti dostop
To evaluate the efficacy of sample pooling compared to the individual analysis for the diagnosis of coronavirus disease 2019 (COVID-19) by using different commercial platforms for nucleic acid ...extraction and amplification.
A total of 3519 nasopharyngeal samples received at nine Spanish clinical microbiology laboratories were processed individually and in pools (342 pools of ten samples and 11 pools of nine samples) according to the existing methodology in place at each centre.
We found that 253 pools (2519 samples) were negative and 99 pools (990 samples) were positive; with 241 positive samples (6.85%), our pooling strategy would have saved 2167 PCR tests. For 29 pools (made out of 290 samples), we found discordant results when compared to their correspondent individual samples, as follows: in 22 of 29 pools (28 samples), minor discordances were found; for seven pools (7 samples), we found major discordances. Sensitivity, specificity and positive and negative predictive values for pooling were 97.10% (95% confidence interval (CI), 94.11–98.82), 100%, 100% and 99.79% (95% CI, 99.56–99.90) respectively; accuracy was 99.80% (95% CI, 99.59–99.92), and the kappa concordant coefficient was 0.984. The dilution of samples in our pooling strategy resulted in a median loss of 2.87 (95% CI, 2.46–3.28) cycle threshold (Ct) for E gene, 3.36 (95% CI, 2.89–3.85) Ct for the RdRP gene and 2.99 (95% CI, 2.56–3.43) Ct for the N gene.
We found a high efficiency of pooling strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA testing across different RNA extraction and amplification platforms, with excellent performance in terms of sensitivity, specificity and positive and negative predictive values.
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