631 research outputs found
In vitro clonal propagation of locally cultivated pink colour Gladiolus var. Neelima through Cormel-sprout culture
Micropropagation provides an economic advantage for the propagation of a particular crop like gladiolus, a beautiful flowering plant which emits expression of love. Propagation by conventional method is a slow process and pathogen keep on accumulation generation after generation which reduces yield and quality of flower and also generates insufficient propagules. An efficient propagation system could overcome those variabilities and meet the increasing demand of propagules production for the growing of gladiolus in the country while it is an exporting plant in Bangladesh. Moreover, establishment of a plant regeneration system through direct organogenesis or via callus is also a prerequisite to further in vitro genetic manipulation of the cultivar. Demand for disease free planting materials is increasing day by day and crop like vegetatively propagated plant is an appropriate means to generate propagules through in vitro techniques. Production of sufficient numbers of plants of a unique genotype is possible using in vitro culture system. In this study, the effect of various concentrations and combinations of plant growth regulators for in vitro regeneration of gladiolus was described using cormel-sprout as explants. However, an efficient in vitro plant regeneration protocol in locally cultivated pink colour Gladiolus var. Neelima was established on MS media with various hormonal supplements using cormel-sprout as explants. Ninety (90) percent of the explants responded for shooting on 0.5 mg/L BA + 0.5 mg/L Kin within the culture initiation period of 90 days. The average number of shoot per explants was 8 ±1.20 and the average shoot length of 12.40 ±2.15 cm were observed in this medium. Shoots are rooted well when they were excised individually and implanted on half strength of MS medium supplemented with 1.0 mg/l IBA, in which 90% of the shoot induced roots. The average number of root per shoot was 10 ± 1.20 and the average root length of 8.50 ± 1.25 cm were observed in this medium after culture of 30 days. Eighty (80) percent of the in vitro raised plantlets were survived in the natural environment
SCREENING OF SOME RESTORER AND MAINTAINER HYBRID RICE LINES AGAINST SHEATH BLIGHT (Rhizoctonia solani)
An experiment was conducted at the field laboratory of Genetics and Plant Breeding Department, BAU, Mymensingh during July to December, 2000. Forty-four test entries of parental lines of rice with one susceptible (BR 11) and one resistant check (BRRI dhan 29) were screened against sheath blight (Rhizoctonia solani) at maximum tillering and flowering stage in the field. The pathogenicity test was studied in the laboratory. Ten lines were resistant, 31 were moderately resistant and 3 showed moderately susceptible reaction at maximum tillering stage. At flowering stage only 2 lines were resistant, 24 were moderately resistant and 18 lines were moderately susceptible
Seasonal and Altitudinal Prevalence of Fascioliasis in Buffalo in Eastern Nepal
Buffalo is the most important livestock commodities for milk, meat production and several other multipurpose uses distributed densely from southern tarai to northern mid-hills in Nepal. Among several internal parasitic diseases fascioliasis is highly economic one caused by Fasciola in buffaloes. However, there are only few studies carried on prevalence of fascioliasis emphasizing buffaloes in relation to seasonal (summer and rainy, and winter) and altitudinal variations. Therefore, we examined prevalence of fascioliasis seasonally and vertically. For the purpose, we selected two districts of eastern Nepal and sampled from low altitude area known as Madhesha ranging from 175-200, Dhankuta from 800-1200 m, and Murtidhunga from 1800-2200 m elevation from the sea level, representing tarai, mid hills and high hills, respectively. Altogether from February 2013 to January 2014 at every two months interval we collected 798 fecal samples from buffaloes; 282 from Murtidhunga, 239 from Dhankuta and 277 from Madhesha. The samples were examined microscopically for the presence of Fasciola eggs using sedimentation technique. Results showed that overall prevalence of fascioliasis in buffaloes was 39.9% (319/798), ranging highest 42.6%in Madhesha followed by 39.7% in Murtidhunga and 37.2% in Dhankuta, respectively. The prevalence of fascioliasis was found to be significantly (p <0.05) high in winter (44.9%) comparing to rainy season (34.4%). The prevalence of fascioliasis in buffaloes was relatively higher in low altitude than high altitude, although it was not statistically significant (p <0.05). In our findings the female buffaloes showed higher prevalence for fascioliasis than in male. Since the fascioliasis in buffaloes is highly endemic, thus strategic deworming in high risk period is recommended along with measure to prevent pasture contamination with buffalo feces
Metal-Adapted Bacteria Isolated From Wastewaters Produce Biofilms by Expressing Proteinaceous Curli Fimbriae and Cellulose Nanofibers
Bacterial biofilm plays a pivotal role in bioremediation of heavy metals from wastewaters. In this study, we isolated and identified different biofilm producing bacteria from wastewaters. We also characterized the biofilm matrix [i.e., extracellular polymeric substances (EPS)] produced by different bacteria. Out of 40 isolates from different wastewaters, only 11 (27.5%) isolates (static condition at 28°C) and 9 (22.5%) isolates (agitate and static conditions at 28 and 37°C) produced air–liquid (AL) and solid–air–liquid (SAL) biofilms, respectively, only on salt-optimized broth plus 2% glycerol (SOBG) but not in other media tested. Biomass biofilms and bacteria coupled with AL biofilms were significantly (P ≤ 0.001) varied in these isolates. Escherichia coli (isolate ENSD101 and ENST501), Enterobacter asburiae (ENSD102), Enterobacter ludwigii (ENSH201), Pseudomonas fluorescens (ENSH202 and ENSG304), uncultured Vitreoscilla sp. (ENSG301 and ENSG305), Acinetobacter lwoffii (ENSG302), Klebsiella pneumoniae (ENSG303), and Bacillus thuringiensis (ENSW401) were identified based on 16S rRNA gene sequencing. Scanning electron microscope (SEM) images revealed that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, A. lwoffii ENSG302, and K. pneumoniae ENSG303 are highly fibrous, compact, and nicely interlinked as compared to the biofilm developed by E. ludwigii ENSH201 and B. thuringiensis ENSW401. X-ray diffraction (XRD) results indicated that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 are non-crystalline amorphous nature. Fourier transform infrared (FTIR) spectroscopy showed that proteins and polysaccharides are the main components of the biofilms. Congo red binding results suggested that all these bacteria produced proteinaceous curli fimbriae and cellulose-rich polysaccharide. Production of cellulose was also confirmed by Calcofluor binding- and spectrophotometric assays. E. asburiae ENSD102, Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 were tested for their abilities to form the biofilms exposure to 0 to 2000 mg/L of copper sulfate (for Cu), zinc sulfate (for Zn), lead nitrate (for Pb), nickel chloride (for Ni), and potassium dichromate (for Cr), several concentrations of these metals activated the biofilm formation. The polysaccharides is known to sequester the heavy metals thus, these bacteria might be applied to remove the heavy metals from wastewater
Machine Learning and Meta-Analysis Approach to Identify Patient Comorbidities and Symptoms that Increased Risk of Mortality in COVID-19
Background: Providing appropriate care for people suffering from COVID-19,
the disease caused by the pandemic SARS-CoV-2 virus is a significant global
challenge. Many individuals who become infected have pre-existing conditions
that may interact with COVID-19 to increase symptom severity and mortality
risk. COVID-19 patient comorbidities are likely to be informative about
individual risk of severe illness and mortality. Accurately determining how
comorbidities are associated with severe symptoms and mortality would thus
greatly assist in COVID-19 care planning and provision.
Methods: To assess the interaction of patient comorbidities with COVID-19
severity and mortality we performed a meta-analysis of the published global
literature, and machine learning predictive analysis using an aggregated
COVID-19 global dataset.
Results: Our meta-analysis identified chronic obstructive pulmonary disease
(COPD), cerebrovascular disease (CEVD), cardiovascular disease (CVD), type 2
diabetes, malignancy, and hypertension as most significantly associated with
COVID-19 severity in the current published literature. Machine learning
classification using novel aggregated cohort data similarly found COPD, CVD,
CKD, type 2 diabetes, malignancy and hypertension, as well as asthma, as the
most significant features for classifying those deceased versus those who
survived COVID-19. While age and gender were the most significant predictor of
mortality, in terms of symptom-comorbidity combinations, it was observed that
Pneumonia-Hypertension, Pneumonia-Diabetes and Acute Respiratory Distress
Syndrome (ARDS)-Hypertension showed the most significant effects on COVID-19
mortality.
Conclusions: These results highlight patient cohorts most at risk of COVID-19
related severe morbidity and mortality which have implications for
prioritization of hospital resources
Slow Light Propagation in a Thin Optical Fiber via Electromagnetically Induced Transparency
We propose a novel configuration that utilizes electromagnetically induced
transparency (EIT) to tailor a fiber mode propagating inside a thin optical
fiber and coherently control its dispersion properties to drastically reduce
the group velocity of the fiber mode. The key to this proposal is: the
evanescent-like field of the thin fiber strongly couples with the surrounding
active medium, so that the EIT condition is met by the medium. We show how the
properties of the fiber mode is modified due to the EIT medium, both
numerically and analytically. We demonstrate that the group velocity of the new
modified fiber mode can be drastically reduced (approximately 44 m/sec) using
the coherently prepared orthohydrogen doped in a matrix of parahydrogen crystal
as the EIT medium.Comment: 10 pages in two column RevTex4, 6 Figure
A blind hierarchical coherent search for gravitational-wave signals from coalescing compact binaries in a network of interferometric detectors
We describe a hierarchical data analysis pipeline for coherently searching
for gravitational wave (GW) signals from non-spinning compact binary
coalescences (CBCs) in the data of multiple earth-based detectors. It assumes
no prior information on the sky position of the source or the time of
occurrence of its transient signals and, hence, is termed "blind". The pipeline
computes the coherent network search statistic that is optimal in stationary,
Gaussian noise, and allows for the computation of a suite of alternative
statistics and signal-based discriminators that can improve its performance in
real data. Unlike the coincident multi-detector search statistics employed so
far, the coherent statistics are different in the sense that they check for the
consistency of the signal amplitudes and phases in the different detectors with
their different orientations and with the signal arrival times in them. The
first stage of the hierarchical pipeline constructs coincidences of triggers
from the multiple interferometers, by requiring their proximity in time and
component masses. The second stage follows up on these coincident triggers by
computing the coherent statistics. The performance of the hierarchical coherent
pipeline on Gaussian data is shown to be better than the pipeline with just the
first (coincidence) stage.Comment: 12 pages, 3 figures, accepted for publication in Classical and
Quantum Gravit
First LIGO search for gravitational wave bursts from cosmic (super)strings
We report on a matched-filter search for gravitational wave bursts from
cosmic string cusps using LIGO data from the fourth science run (S4) which took
place in February and March 2005. No gravitational waves were detected in 14.9
days of data from times when all three LIGO detectors were operating. We
interpret the result in terms of a frequentist upper limit on the rate of
gravitational wave bursts and use the limits on the rate to constrain the
parameter space (string tension, reconnection probability, and loop sizes) of
cosmic string models.Comment: 11 pages, 3 figures. Replaced with version submitted to PR
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