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A National Survey to Analyze the Prevailing Approaches to Elementary School Guidance
The problem of this study was to analyze the prevailing approaches to elementary school guidance in the United States
Obscuration, environments and host galaxies of active galactic nuclei.
The work contained within this thesis
Is made up primarily of two pieces
Both address active galactic nuclei
And the galaxies that live nearby
The obscured fraction of the population
Is the topic of one publication
And the type-II fraction in the optical regime
In chapter four this is the theme
I research the vicinity overdensity
Around radio galaxies in chapter three, you’ll see
I reduce some spectra at redshift one
But not all observations in the end got done
With the spectra I have I do what I can
As if all target observations had actually ran
In the end I conclude with results and the theme
of research to be done further downstream.
The works contained herein addresses two major topics in extragalactic
astrophysics, namely the Type-II AGN fraction and the Overdensity-Radio power
relation.
Quantifying the Type-II AGN fraction has been attempted by many works
in many different observational regimes, finding rather contrasting results.
Accretion onto supermassive black holes contributes between 5 per cent and 20
per cent of the luminosity of the Universe, and seems to be closely linked to
star formation processes. The large uncertainty on this value is due to the ill-determined
contribution from obscured accretion, namely the Type-II fraction.
In Chapters 3 and 4 I address this issue from a theoretical standpoint in the X-ray
regime and an observational standpoint in the optical regime respectively.
In Chapter 3 I show how crude X-ray spectroscopy of partially obscured AGN
can lead to catastrophic underestimations of the intrinsic X-ray luminosity of
these sources. Acting over an entire population, these partial obscurers can
produce an obscured AGN fraction which decreases as a function of observed
luminosity. The results are consistent with observations in the X-ray vs. IR
luminosity of AGN classes.
In Chapter 4 I select a statistically significant sample of AGN from an unbiased
250μm galaxy sample. After spectroscopic classification I find the optical Type-
II AGN fraction to be consistent across several decades in [OIII] luminosity, a
common proxy for intrinsic AGN luminosity. I also investigate the relation of
AGN activity to host galaxy mass, as well as star formation activity and star
formation history.
Probing the environments of protoclusters will help to constrain the models of
structure formation in the Universe. Until now, no dataset has been big enough
to probe the environments of high redshift radio galaxies at a statistical level;
While many believe that the feedback processes of high luminosity radio jets will
have a direct impact on star formation in the surrounding medium it has not
been tested. In Chapter 2 I investigate this on an statistical level, finding no
meaningful correlation between radio galaxy radio power and source overdensity
in the vicinities of these sources.
In Chapter 5 I discuss the reduction of a 24μm sample at redshift z ∼ 1 for
direct comparison with a local 12μm sample. With only a fraction of the target
sample being observed, no statistically significant results could be derived, but the
objects are spectroscopically classified and spectroscopic redshifts are measured
where possible. Correlations in the data set are investigated and the limitations
of the sample selection strategy are discussed
Full Counting Statistics of Topological Defects After Crossing a Phase Transition
We consider the number distribution of topological defects resulting from the
finite-time crossing of a continuous phase transition and identify signatures
of universality beyond the mean value, predicted by the Kibble-Zurek mechanism.
Statistics of defects follows a binomial distribution with
Bernouilli trials associated with the probability of forming a topological
defect at the locations where multiple domains merge. All cumulants of the
distribution are predicted to exhibit a common universal power-law scaling with
the quench time in which the transition is crossed. Knowledge of the
distribution is used to discuss the onset of adiabatic dynamics and bound rare
events associated with large deviations.Comment: Main text: 6 pages, 4 figures. Supplemental Material: 8 pages, 6
figure
The Mid-Infrared Environments of High-Redshift Radio Galaxies
Taking advantage of the impressive sensitivity of Spitzer to detect massive
galaxies at high redshift, we study the mid-infrared environments of powerful,
high-redshift radio galaxies at 1.2<z<3. Galaxy cluster member candidates were
isolated using a single Spitzer/IRAC mid-infrared color criterion,
[3.6]-[4.5]>-0.1 (AB), in the fields of 48 radio galaxies at 1.2<z<3. This
simple IRAC color selection is effective at identifying galaxies at z>1.2.
Using a counts-in-cell analysis, we identify a field as overdense when 15 or
more red IRAC sources are found within 1arcmin (i.e.,~0.5Mpc at 1.2<z<3) of the
radio galaxy to the 5sigma flux density limits of our IRAC data (f3.6=11.0uJy,
f4.5=13.4uJy). We find that radio galaxies lie preferentially in medium to
dense regions, with 73% of the targeted fields denser than average. Our
(shallow) 120s data permit the rediscovery of previously known clusters and
protoclusters associated with radio galaxies as well as the discovery of new
promising galaxy cluster candidates at z>1.2.Comment: 14 pages, 7 figures, 3 tables, accepted for publication in Ap
YouTube as a neurosurgical training tool for the insertion of external ventricular drain
Objectives
YouTube is the largest open-access media website and an increasingly recognised resource in Medical Education, with much content related to Neurosurgery. External Ventricular Drain (EVD) insertion is frequently undertaken by neurosurgical trainees. Online and distant learning have gained popularity during this COVID-19 pandemic more than ever. We evaluated content on YouTube as to its use as an effective open-access learning resource for EVD insertion as a key neurosurgical procedure.
Methods
A keyword search identified videos related to EVD insertion on 01/06/2020. Inclusion criteria was created to focus on content aimed at describing the technique of EVD insertion. An educational scoring system was devised related to the procedure of EVD insertion. Each video was scored on our educational score, JAMA Benchmark Criteria and Global Quality Score (GQS). They were subsequently categorised as effective or ineffective.
Results
A total of 12/700 videos met inclusion criteria. Dates posted ranged from 01/07/2012 – 24/04/2019, with views range 359 – 166,388, and mean of 30,531 (SD 49,570). Four videos (33%) were considered an effective learning resource. The cohort had a mean educational score of 6.91 (SD 3.86), with median JAMA score and GQS 2/4 (SD 0.62) and 2/5 (SD 1.6) respectively. A strong correlation was found between viewership and score (R 0.85, p < 0.005)
Conclusion
The majority of YouTube content on EVD insertion is an ineffective resource. Neurosurgeons and Institutions could harness YouTubes broad access by posting high-quality educational content. This is more important than ever with increasing emphasis on online training resources, YouTube included
The Freshman, vol. 5, no. 18
The Freshman was a weekly, student newsletter issued on Mondays throughout the academic year. The newsletter included calendar notices, coverage of campus social events, lectures, and athletic teams. The intent of the publication was to create unity, a sense of community, and class spirit among first year students
Thrombolytic removal of intraventricular haemorrhage in treatment of severe stroke: results of the randomised, multicentre, multiregion, placebo-controlled CLEAR III trial
Background:
Intraventricular haemorrhage is a subtype of intracerebral haemorrhage, with 50% mortality and serious disability for survivors. We aimed to test whether attempting to remove intraventricular haemorrhage with alteplase versus saline irrigation improved functional outcome.
Methods:
In this randomised, double-blinded, placebo-controlled, multiregional trial (CLEAR III), participants with a routinely placed extraventricular drain, in the intensive care unit with stable, non-traumatic intracerebral haemorrhage volume less than 30 mL, intraventricular haemorrhage obstructing the 3rd or 4th ventricles, and no underlying pathology were adaptively randomly assigned (1:1), via a web-based system to receive up to 12 doses, 8 h apart of 1 mg of alteplase or 0·9% saline via the extraventricular drain. The treating physician, clinical research staff, and participants were masked to treatment assignment. CT scans were obtained every 24 h throughout dosing. The primary efficacy outcome was good functional outcome, defined as a modified Rankin Scale score (mRS) of 3 or less at 180 days per central adjudication by blinded evaluators. This study is registered with ClinicalTrials.gov, NCT00784134.
Findings:
Between Sept 18, 2009, and Jan 13, 2015, 500 patients were randomised: 249 to the alteplase group and 251 to the saline group. 180-day follow-up data were available for analysis from 246 of 249 participants in the alteplase group and 245 of 251 participants in the placebo group. The primary efficacy outcome was similar in each group (good outcome in alteplase group 48% vs saline 45%; risk ratio [RR] 1·06 [95% CI 0·88–1·28; p=0·554]). A difference of 3·5% (RR 1·08 [95% CI 0·90–1·29], p=0·420) was found after adjustment for intraventricular haemorrhage size and thalamic intracerebral haemorrhage. At 180 days, the treatment group had lower case fatality (46 [18%] vs saline 73 [29%], hazard ratio 0·60 [95% CI 0·41–0·86], p=0·006), but a greater proportion with mRS 5 (42 [17%] vs 21 [9%]; RR 1·99 [95% CI 1·22–3·26], p=0·007). Ventriculitis (17 [7%] alteplase vs 31 [12%] saline; RR 0·55 [95% CI 0·31–0·97], p=0·048) and serious adverse events (114 [46%] alteplase vs 151 [60%] saline; RR 0·76 [95% CI 0·64–0·90], p=0·002) were less frequent with alteplase treatment. Symptomatic bleeding (six [2%] in the alteplase group vs five [2%] in the saline group; RR 1·21 [95% CI 0·37–3·91], p=0·771) was similar.
Interpretation:
In patients with intraventricular haemorrhage and a routine extraventricular drain, irrigation with alteplase did not substantially improve functional outcomes at the mRS 3 cutoff compared with irrigation with saline. Protocol-based use of alteplase with extraventricular drain seems safe. Future investigation is needed to determine whether a greater frequency of complete intraventricular haemorrhage removal via alteplase produces gains in functional status
Burkholderia pseudomallei Isolates from Sarawak, Malaysian Borneo, Are Predominantly Susceptible to Aminoglycosides and Macrolides
Melioidosis is a potentially fatal disease caused by the saprophytic bacterium Burkholderia pseudomallei. Resistance to gentamicin is generally a hallmark of B. pseudomallei, and gentamicin is a selective agent in media used for diagnosis of melioidosis. In this study, we determined the prevalence and mechanism of gentamicin susceptibility found in B. pseudomallei isolates from Sarawak, Malaysian Borneo. We performed multilocus sequence typing and antibiotic susceptibility testing on 44 B. pseudomallei clinical isolates from melioidosis patients in Sarawak district hospitals. Whole-genome sequencing was used to identify the mechanism of gentamicin susceptibility. A novel allelic-specific PCR was designed to differentiate gentamicin-sensitive isolates from wild-type B. pseudomallei. A reversion assay was performed to confirm the involvement of this mechanism in gentamicin susceptibility. A substantial proportion (86%) of B. pseudomallei clinical isolates in Sarawak, Malaysian Borneo, were found to be susceptible to the aminoglycoside gentamicin, a rare occurrence in other regions where B. pseudomallei is endemic. Gentamicin sensitivity was restricted to genetically related strains belonging to sequence type 881 or its single-locus variant, sequence type 997. Whole-genome sequencing identified a novel nonsynonymous mutation within amrB, encoding an essential component of the AmrAB-OprA multidrug efflux pump. We confirmed the role of this mutation in conferring aminoglycoside and macrolide sensitivity by reversion of this mutation to the wild-type sequence. Our study demonstrates that alternative B. pseudomallei selective media without gentamicin are needed for accurate melioidosis laboratory diagnosis in Sarawak. This finding may also have implications for environmental sampling of other locations to test for B. pseudomallei endemicity
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