21 research outputs found
Normalization: A Preprocessing Stage
As we know that the normalization is a pre-processing stage of any type
problem statement. Especially normalization takes important role in the field
of soft computing, cloud computing etc. for manipulation of data like scale
down or scale up the range of data before it becomes used for further stage.
There are so many normalization techniques are there namely Min-Max
normalization, Z-score normalization and Decimal scaling normalization. So by
referring these normalization techniques we are going to propose one new
normalization technique namely, Integer Scaling Normalization. And we are going
to show our proposed normalization technique using various data sets.Comment: 4 pages, 3 figures, 3 table
Further evidence for intra-night optical variability of radio-quiet quasars
Although well established for BL Lac objects and radio-loud quasars, the
occurrence of intra-night optical variability (INOV) in radio-quiet quasars is
still debated, primarily since only a handful of INOV events with good
statistical significance, albeit small amplitude, have been reported so far.
This has motivated us to continue intra-night optical monitoring of bona-fide
radio-quiet quasars (RQQs). Here we present the results for a sample of 11 RQQs
monitored by us on 19 nights. On 5 of these nights a given RQQ was monitored
simultaneously from two well separated observatories. In all, two clear cases
and two probable case of INOV were detected. From these data, we estimate an
INOV duty cycle of 8% for RQQs which would increase to 19% if the
`probable variable' cases are also included. Such comparatively small INOV duty
cycles for RQQs, together with the small INOV amplitudes (1%), are in
accord with the previously deduced characteristics of this phenomenon.Comment: 15 Pages, 4 Tables, 24 Figures; Accepted in BAS
Rapid optical variability of TeV blazars
In this first systematic attempt to characterise the intranight optical
variability (INOV) of TeV detected blazars, we have monitored a well defined
set of 9 TeV blazars on total 26 nights during 2004-2010. In this R (or V)-band
monitoring programme only one blazar was monitored per night for a minimum
duration of 4 hours. Using the CCD, an INOV detection threshold of ~ 1-2 % was
achieved in the densely sampled DLCs. We have further expanded the sample by
including another 13 TeV blazars from literature. This enlarged sample of 22
TeV blazars, monitored on a total of 116 nights (including 55 nights newly
reported here), has enabled us to arrive at the first estimate of the INOV duty
cycle of TeV detected blazars. Applying the C-test, the INOV DC is found to be
59 %, which decreases to 47 % if only INOV fractional amplitudes above 3 % are
considered. These observations also permit, for the first time, a comparison of
the INOV characteristics of the two major subclasses of TeV detected BL Lacs,
namely LBLs and HBLs, for which we find the INOV DCs to be ~ 63 % and ~ 38 %,
respectively. This demonstrates that the INOV differential between LBLs and
HBLs persists even when only their TeV detected subsets are considered. Despite
dense sampling, the intranight light curves of the 22 TeV blazars have not
revealed even a single feature on time scale substantially shorter than 1 hour,
even though the inner jets of TeV blazars are believed to have exceptionally
large bulk Lorentz factors (and correspondingly stronger time compression). An
intriguing feature, clearly detected in the light curve of the HBL J1555+1111,
is a 4 per cent `dip' on a 1 hour timescale. This unique feature could have
arisen from absorption in a dusty gas cloud, occulting a superluminally moving
optical knot in the parsec scale jet of this relatively luminous BL Lacs
object.Comment: 39 pages, 3 figures, accepted for publication in MNRA
Intra-night optical variability of core dominated radio quasars: the role of optical polarization
Context. Rapid variations in optical flux are seen in many quasars and all blazars. The amount of variability in different classes of active galactic nuclei has been studied extensively but many questions remain unanswered. Aims. We present the results of a long-term programme to investigate the intra-night optical variability (INOV) of powerful flat spectrum radio core-dominated quasars (CDQs), with a focus on probing the relationship of INOV to the degree of optical polarization. Methods. We observed a sample of 16 bright CDQs showing strong broad optical emission lines and consisting of both high and low optical polarization quasars (HPCDQs and LPCDQs). In this first systematic study of its kind, we employed the 104-cm Sampurnanand telescope, the 201-cm Himalayan Chandra telescope and the 200-cm IUCAA-Girawali Observatory telescope, to carry out R-band monitoring on a total of 47 nights. Using the CCD as an N-star photometer to densely monitor each quasar for a minimum duration of about 4 h per night, INOV exceeding ~1–2 per cent could be reliably detected. Combining these INOV data with those taken from the literature, after ensuring conformity with the basic selection criteria we adopted for the 16 CDQs monitored by us, we were able to increase the sample size to 21 CDQs (12 LPCDQs and 9 HPCDQs) monitored on a total of 73 nights. Results. As the existence of a prominent flat-spectrum radio core signifies that strong relativistic beaming is present in all these CDQs, the definitions of the two sets differ primarily in fractional optical polarization, with the LPCDQs showing a very low median Pop ≃ 0.4 per cent. Our study yields an INOV duty cycle (DC) of ~28 per cent for the LPCDQs and ~68 percent for HPCDQs. If only strong INOV with fractional amplitude above 3 per cent is considered, the corresponding DCs are ~7 per cent and ~40 per cent, respectively. Conclusions. From this strong contrast between the two classes of luminous, relativistically beamed quasars, it is apparent that relativistic beaming is normally not a sufficient condition for strong INOV and a high optical polarization is the other necessary condition. Moreover, the correlation is found to persist for many years after the polarization measurements were made. Some possible implications of this result are pointed out, particularly in the context of the recently detected rapid γ-ray variability of blazars
Optical variability of radio-intermediate quasars
We report the results of our intensive intranight optical monitoring of 8
`radio-intermediate quasars' (RIQs) having flat or inverted radio spectra. The
monitoring was carried out in {\it R-} band on 25 nights during 2005-09. An
intranight optical variability (INOV) detection threshold of 1--2% was
achieved for the densely sampled differential light curves (DLCs). These
observations amount to a large increase over those reported hitherto for this
rare and sparsely studied class of quasars which can, however, play an
important role in understanding the link between the dominant varieties of
powerful AGN, namely the radio-quiet quasars (RQQs), radio-loud quasars (RLQs)
and blazars. Despite the probable presence of relativistically boosted nuclear
jets, clear evidence for INOV in our extensive observations was detected only
on one night. These results demonstrate that as a class, RIQs are much less
extreme in nuclear activity compared to blazars. The availability in the
literature of INOV data for another 2 RIQs conforming to our selection criteria
allowed us to enlarge the sample to 10 RIQs (monitored on a total of 42 nights
for a minimum duration of hours per night). The absence of large
amplitude INOV persists in this enlarged sample. This extensive
database has enabled us to arrive at the first estimate for the INOV Duty Cycle
(DC) of RIQs. The DC is found to be small ( 9%). The corresponding value
is known to be for BL Lacs and for RLQs and RQQs. On
longer-term, the RIQs are found to be fairly variable with typical amplitudes
of 0.1-mag. The light curves of these RIQs are briefly discussed in
the context of a theoretical framework proposed earlier for linking this rare
kind of quasars to the much better studied dominant classes of quasars.Comment: 35 pages, 2 figures, 3 tables, accepted for publication in MNRA
Unusual optical quiescence of the classical BL Lac object PKS 0735+178 on intranight time-scale
We present the result of our extensive intranight optical monitoring of the well-known low-energy peaked BL Lac (LBL) object PKS 0735+178. This long-term follow-up consists of R -band monitoring for a minimum duration of ∼4 hours, on 17 nights spanning 11 years (1998–2008). Using the CCD as an N-star photometer, a detection limit of around 1 per cent was attained for the intranight optical variability (INOV). Remarkably, an INOV amplitude of ≥3 per cent on hour-like time-scale was not observed on any of the 17 nights, even though the likelihood of a typical LBL showing such INOV levels in a single session of >4 hours duration is known to be high (∼50 per cent) . Our observations have thus established a peculiar long-term INOV quiescence of this radio-selected BL Lac object. Moreover, the access to unpublished optical monitoring data of similarly high sensitivity, acquired in another programme, has allowed us to confirm the same anomalous INOV quiescence of this LBL all the way back to 1989, the epoch of its historically largest radio outburst. Here, we present observational evidence revealing the very unusual INOV behaviour of this classical BL Lac object and discuss this briefly in the context of its other known exceptional properties.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74920/1/j.1365-2966.2009.15385.x.pd
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
<i style="">In silico</i> 3-D structure prediction of H1N1 2009 neuraminidase and comparative analysis of coding statistics of mutated genes
148-155The enzyme neuraminidase (NA), coded by H1N1
virus, catalyses the removal of terminal sialic acid from viral and cellular
glycoconjugates. It cleaves the terminal sialic acid on the glycosylated NA
during virus budding to facilitate virus release. The outbreak of Swine flu is
suspected to be caused due to H274Y mutation in the neuraminidase enzyme of
H1N1 2009 strain. The present study involves 3-D structure modeling of mutated
neuraminidase of the strain A/Poland/274/2009 (H1N1) by MODELLER9v7 and
comparative analysis of coding statistics among NA gene of 3 mutated H1N1
strains with GenBank accession numbers GU112751, GU371269 and CY053923. The
analysis of 3-D model revealed that NAs have a common fold characterised by
β-pleated sheet flanked either side by helices. The amino terminal end of
the molecule is occupied by β-α-β motif and carboxy terminal end by β-hairpin
motif. The molecule is characterised by
24 strands and 3 helices. The α1 helix is the longest among the
three helices. The comparative analysis of coding statistics indicates that the
statistical features f1, f5, f6 and f7
have the most discriminating power for the individual recognition of the
mutated neuraminidase genes of H1N1 2009
Comparative intra-night optical variability of high and low polarization quasars with dominant radio cores
We present the initial results of a programme to investigate the dependence of intra-night optical variability (INOV) of powerful AGN, on the degree of optical polarization. For the first systematic study of this kind, we employed 104-cm Sampurnanand telescope (ST) and 201-cm Himalayan Chandra telescope (HCT) to carry out R-band monitoring of a sample of 8 optically bright radio core dominated quasars showing low optical polarization (P < 3 %) (LPCDQ). Selected from literature in an biased manner, having flat or inverted spectrum at giga hertz frequencies, these LPCDQs were monitored on a total of 23 nights, by monitoring only one of them per night (average duration of monitoring being 5.6 hr per night). Using the CCD as an N-star photometer, a INOV detection threshold of approx 1-2% could be achieved for these densely sampled differential light curves (DLCs). The microvariations were clearly detected on many nights, with peak to peak INOV amplitude ranging from 1.2% to 5.3% (median 2%). While the presence of dominant radio core at centimetre wavelenghts in all these quasars signifies relativistic beaming, they differ strongly from BL Lac objects in showing a very low optical polarization (median P_op0.4 %). From our observations we determine the duty cycle (DC) of 43pm10%, for INOV for these LPCDQs. The corresponding value for BL Lac objects is known to be around 60%. Thus, using these measurements we evaluate the comaparative roles of optical polarization and relativistic beaming on the phenomenon of intra-night optical variability
Evaluation of p53 protein expression in Barrett esophagus
Background: Loss of heterozygosity of p53 along with aneuploidy is deemed to be the early molecular steps in Barrett metaplasia-dysplasia-adenocarcinoma sequence. Objective biomarkers need to be used along with microscopy for risk stratification to predict the progression of Barrett esophagus (BE) to carcinoma. Aim: This study aims to study p53 protein expression in dysplasia and correlate the same with morphology in BE. Materials and Methods: A time-bound study was conducted from January 2011 to June 2015. All esophageal biopsies showing histological evidence of columnar epithelium with the presence of goblet cells were included. The cases which showed dysplasia were graded on hematoxylin and eosin stain. Evaluation of p53 immunohistochemistry staining was done on all the cases of BE. Dysplasia was correlated with the expression of p53 using Chi-square value (χ2) and Fischer's exact test wherever appropriate. P < 0.05 was considered to be statistically significant. Results: Of 829 esophageal biopsies received, 119 were endoscopically suspected to be BE, of which 85 cases were confirmed on microscopy. In our study, there were 75 cases negative for dysplasia (88.2%), 8 with low-grade dysplasia (LGD) (9.4%), and two with high-grade dysplasia (HGD) (2.4%). Three cases of BE had associated adenocarcinoma. Immunostaining with p53 done on all the 85 cases showed positive staining in all cases with LGD, one with HGD and two with adenocarcinoma. In the present study, immunostaining with p53 showed 90% sensitivity, 89.3% specificity, positive predictive value of 52.9%, and negative predictive value of 98.5%. Conclusion: The technical simplicity, easy availability, and comparatively lower cost enhance the role of p53 as a biomarker in risk stratification for patients with BE