44 research outputs found
Crop-to-wild introgression in the European wild apple Malus sylvestris in Northern Britain 2 3 MARKUS RUHSAM
International audienc
Effect Of Lead Acetate (Pb(Ch3coo)2 On The Growth Of Marine Microalgaes Chlorella vulgaris (Beijerink, 1890)
Microalgae are single-celled microorganisms, forming colonies and are very commonly found in large waters such as seas, lakes, rivers, and swamps. The purpose of this study was to determine the growth and density of microalgae Chlorella vulgaris in a controlled container with the administration of lead acetate at different concentrations. Cell growth of Chlorella vulgaris with samples of marine microalgae Chlorella vulgaris from culture containers. At the beginning of the exponential phase, the microalgae were given lead acetate in 3 containers with concentrations of 30 ppm, 50 ppm, 80 ppm, and control/without treatment. The results showed that the growth of Chlorella vulgaris cells with lead acetate administration experienced unstable growth compared to those without lead acetate administration (control).Keywords: Microalgae; Chlorella vulgaris; Culture; Lead AcetateAbstrakMikroalga merupakan mikroorganisme bersel satu, membentuk koloni dan sangat banyak dijumpai di perairan besar seperti pada laut, danau, sungai serta perairan payau. Tujuan dari penelitian ini adalah untuk mengetahui pertumbuhan dan kepadatan mikroalga Chlorella vulgaris dalam wadah terkontrol dengan pemberian timbal asetat pada konsentrasi yang berbeda. Pertumbuhan sel Chlorella vulgaris denga Sampel mikroalga laut Chlorella vulgaris berasal dari wadah kultur. Pada awal fase eksponensial, mikroalga diberikan timbal asetat ke dalam 3 wadah dengan konsentrasi 30 ppm, 50 ppm, 80 ppm serta kontrol/tanpa perlakuan. Hasil penelitian menunjukkan bahwa pertumbuhan sel Chlorella vulgaris dengan pemberian timbal asetat mengalami pertumbuhan yang tidak stabil dibandingkan tanpa pemberian timbal asetat (kontrol).Kata kunci: Mikroalga; Chlorella vulgaris; Kultur; Timbal Aseta
HgCdTe Avalanche Photodiode Array Detectors with Single Photon Sensitivity and Integrated Detector Cooler Assemblies for Space Lidar Applications
A HgCdTe avalanche photodiode (APD) focal plane array assembly with linear mode photon-counting capability has been developed for space lidar applications. An integrated detector cooler assembly (IDCA) has been built using a miniature Stirling cooler. A microlens array has been included to improve the fill factor. The HgCdTe APD has a spectral response from 0.9- to 4.3-m wavelengths, a photon detection efficiency as high as 70%, and a dark count rate of <250 kHz at 110 K. The mass of the IDCA is 0.8 kg and the total electrical power consumption is about 7 W. The HgCdTe APD arrays have been characterized at NASA Goddard Space Flight Center. A series of environmental tests have been conducted for the IDCAs, including vibration, thermal cycling, and thermal vacuum tests. A description of the device and the test results at NASA are given in this paper
Single Photon HgCdTe Avalanche Photodiode and Integrated Detector Cooler Assemblies for Space Lidar Applications
A linear mode photon counting HgCdTe avalanche photodiode (APD) focal plane array (FPA) detector was developed for space lidar applications. An integrated detector cooler assembly (IDCA) was manufactured using a miniature Stirling cooler. The HgCdTe APD demonstrated a greater than 60% photon detection efficiency from 0.9 to 4.3 m wavelength and a dark count rate less than 250,000/s. The IDCA cooled the FPA to 110K from ambient room temperature at a total electrical power of 7 W. The IDCA has passed environmental tests, including vibration, thermal cycling and thermal vacuum tests
Differential Dynamics of Transposable Elements during Long-Term Diploidization of Nicotiana Section Repandae (Solanaceae) Allopolyploid Genomes
PubMed ID: 23185607This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Time-calibrated phylogenetic trees establish a lag between polyploidisation and diversification in Nicotiana (Solanaceae)
We investigate the timing of diversification in allopolyploids of Nicotiana (Solanaceae) utilising sequence data of maternal and paternal origin to look for evidence of a lag phase during which diploidisation took place. Bayesian relaxed clock phylogenetic methods show recent allopolyploids are a result of several unique polyploidisation events, and older allopolyploid sections have undergone subsequent speciation at the polyploid level (i.e. a number of these polyploid species share a singular origin). The independently formed recent polyploid species in the genus all have mean age estimates below 1 million years ago (Ma). Nicotiana  section Polydicliae (two species) evolved 1.5 Ma, N. section Repandae (four species) formed 4 Ma, and N. section Suaveolentes (*35 species) is about 6 million years old. A general trend of higher speciation rates in older polyploids is evident, but diversification dramatically increases at approximately 6 Ma (in section Suaveolentes). Nicotiana sect. Suaveolentes has spectacularly radiated to form 35 species in Australia and some Pacific islands following a lag phase of almost 6 million years. Species have filled new ecological niches and undergone extensive diploidisation (e.g. chromosome fusions bringing the ancestral allotetraploid number, n = 24, down to n = 15 and ribosomal loci numbers back to diploid condition). Considering the progenitors of Suaveolentes inhabit South America, this represents the colonisation of Australia by polyploids that have subsequently undergone a recent radiation into new environments. To our knowledge, this study is the first report of a substantial lag phase being investigated below the family level
Linked read technology for assembling large complex and polyploid genomes
Background: Short read DNA sequencing technologies have revolutionized genome assembly by providing high accuracy and throughput data at low cost. But it remains challenging to assemble short read data, particularly for large, complex and polyploid genomes. The linked read strategy has the potential to enhance the value of short reads for genome assembly because all reads originating from a single long molecule of DNA share a common barcode. However, the majority of studies to date that have employed linked reads were focused on human haplotype phasing and genome assembly.
Results: Here we describe a de novo maize B73 genome assembly generated via linked read technology which contains ~ 172,000 scaffolds with an N50 of 89 kb that cover 50% of the genome. Based on comparisons to the B73 reference genome, 91% of linked read contigs are accurately assembled. Because it was possible to identify errors with \u3e 76% accuracy using machine learning, it may be possible to identify and potentially correct systematic errors. Complex polyploids represent one of the last grand challenges in genome assembly. Linked read technology was able to successfully resolve the two subgenomes of the recent allopolyploid, proso millet (Panicum miliaceum). Our assembly covers ~ 83% of the 1 Gb genome and consists of 30,819 scaffolds with an N50 of 912 kb.
Conclusions: Our analysis provides a framework for future de novo genome assemblies using linked reads, and we suggest computational strategies that if implemented have the potential to further improve linked read assemblies, particularly for repetitive genomes
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Single-dose BNT162b2 vaccine protects against asymptomatic SARS-CoV-2 infection
The BNT162b2 mRNA COVID-19 vaccine (Pfizer-BioNTech) is being utilised internationally for mass COVID-19 vaccination. Evidence of single-dose protection against symptomatic disease has encouraged some countries to opt for delayed booster doses of BNT162b2, but the effect of this strategy on rates of asymptomatic SARS-CoV-2 infection remains unknown. We previously demonstrated frequent pauci- and asymptomatic SARS-CoV-2 infection amongst healthcare workers (HCWs) during the UK’s first wave of the COVID-19 pandemic, using a comprehensive PCR-based HCW screening programme (Rivett et al., 2020; Jones et al., 2020). Here, we evaluate the effect of first-dose BNT162b2 vaccination on test positivity rates and find a fourfold reduction in asymptomatic infection amongst HCWs ≥12 days post-vaccination. These data provide real-world evidence of short-term protection against asymptomatic SARS-CoV-2 infection following a single dose of BNT162b2 vaccine, suggesting that mass first-dose vaccination will reduce SARS-CoV-2 transmission, as well as the burden of COVID-19 disease
Gluttony, excess, and the fall of the planter class in the British Caribbean
Food and rituals around eating are a fundamental part of human existence. They can also be heavily politicized and socially significant. In the British Caribbean, white slaveholders were renowned for their hospitality towards one another and towards white visitors. This was no simple quirk of local character. Hospitality and sociability played a crucial role in binding the white minority together. This solidarity helped a small number of whites to dominate and control the enslaved majority. By the end of the eighteenth century, British metropolitan observers had an entrenched opinion of Caribbean whites as gluttons. Travelers reported on the sumptuous meals and excessive drinking of the planter class. Abolitionists associated these features of local society with the corrupting influences of slavery. Excessive consumption and lack of self-control were seen as symptoms of white creole failure. This article explores how local cuisine and white creole eating rituals developed as part of slave societies and examines the ways in which ideas about hospitality and gluttony fed into the debates over slavery that led to the dismantling of slavery and the fall of the planter class