2,467 research outputs found
Applying Intelligent Open Science to Combat Future Pandemics
The COVID-19 pandemic demonstrated the potential strengths and existing weaknesses of open science practices and open data sharing to addressing urgent social and technological challenges. It was a time when pathogen genomic data was shared worldwide to characterise virus outbreaks, track the mutation and spread of the virus, and develop public health responses. However, this brought a renewed focus to the practice, incentives and infrastructures that crucially enable data sharing and reuse.
In 2022, the Department for Business, Energy and Industrial Strategy commissioned Research Consulting to investigate the opportunities and challenges associated with open data sharing during the pandemic. This work follows a commitment made during the UKâS G7 Presidency, as published in the G7 Research Compact, and its findings are closely aligned to those outlined in the World Health Organizationâs recently published guiding principles for pathogen genome data sharing.
Our talk draws on evidence base of 295 sources, the views of 24 interviewees, and insights from 18 international peer reviewers to present five key lessons that can be learnt to enable preparedness for future pandemics
The experience of meaning in circle dance
Circle dance, which derives from the tradition of folk dances, is practised
worldwide. This article explores the meanings participants attribute to it.
In-depth interviews with 39 participants, teachers and coordinators of
teacher training programmes from the circle dance network in the
United Kingdom were undertaken. Applying a constructivist grounded
theory approach, major categories, representing respectively the
experiences of circle dance participants, teachers and coordinators, were
developed. This article specifically focuses on the first major category,
termed âI canât imagine life without itâ, which relates to the experience of
22 dancers. From an occupational perspective, the study reveals how
participants realise a sense of meaning and satisfaction through
engagement in circle dance and the potential contribution of this
occupation to well-being
3rd international workshop on advances and applications of problem frames
Michael Jackson's Problem Frames are a highly promising approach to early life-cycle software engineering. Their focus moves the engineer back to the problem to be solved rather than forward to the software and solving a poorly defined problem. By applying the Problem Frames approach, the software engineer can understand the problem context and how it is to be affected by the proposed software, and ultimately work towards the right solution for the problem. The influence of the Problem Frames approach and related work is spreading in the fields of domain modelling, business process modelling, requirements engineering, software architecture as well as software engineering in general
The effects of summarization and factual retrieval practice on text comprehension and text retention in elementary education
When reading a text in school, the goal is both text comprehension and text retention. We examined the effects of the learning strategies summarization and factual retrieval practice on third- and fourth-grade pupilsâ text comprehension and retention of factual knowledge from a text, using restudy as a control condition. The experiment was conducted in an authentic classroom setting, with teachers executing the experiment using original course materials. In 2016, 57 regular third- and fourth-grade pupils (M = 9.04 years old) read three different texts, and each applied three different learning strategies (summarization, retrieval practice and restudy, which were counterbalanced across texts) in subsequent practice sessions. After a 2-week delay, a final test was administered. The learning strategy summarization had a larger positive effect on text comprehension than factual retrieval practice, but had a similar effect compared to restudy. The learning strategy factual retrieval practice had a larger positive effect on text retention than both summarization and restudy. Implications for educational practice are discussed
On the Origin of the Dichotomy of Early-Type Galaxies: The Role of Dry Mergers and AGN Feedback
Using a semi-analytical model for galaxy formation, combined with a large
N-body simulation, we investigate the origin of the dichotomy among early-type
galaxies. We find that boxy galaxies originate from mergers with a progenitor
mass ratio and with a combined cold gas mass fraction . Our model accurately reproduces the observed fraction of boxy systems as
a function of luminosity and halo mass, for both central galaxies and
satellites. After correcting for the stellar mass dependence, the properties of
the last major merger of early-type galaxies are independent of their halo
mass. This provides theoretical support for the conjecture of Pasquali et al
(2007) that the stellar mass of an early-type galaxy is the main parameter that
governs its isophotal shape. We argue that the observed dichotomy of early-type
galaxies has a natural explanation within hierarchical structure formation, and
does not require AGN feedback. Rather, we argue that it owes to the fact that
more massive systems (i) have more massive progenitors, (ii) assemble later,
and (iii) have a larger fraction of early-type progenitors. Each of these three
trends causes the cold gas mass fraction of the progenitors of more massive
early-types to be lower, so that their last major merger was dryer. Finally,
our model predicts that (i) less than 10 percent of all early-type galaxies
form in major mergers that involve two early-type progenitors, (ii) more than
95 percent of all boxy early-type galaxies with M_* < 2 \times 10^{10} h^{-1}
\Msun are satellite galaxies, and (iii) about 70 percent of all low mass
early-types do not form a supermassive black hole binary at their last major
merger. The latter may help to explain why low mass early-types have central
cusps, while their massive counterparts have cores.Comment: 13 pages, 8 figures, submitted for publication in MNRA
Sorption-desorption of Imidacloprid and its Metabolites in Soil and Vadose Zone Materials
Sorption-desorption is one of the most important processes affecting the leaching of pesticides through soil because it controls the amount of pesticide available for transport. Subsurface soil properties can significantly affect pesticide transport and the potential for groundwater contamination. This research characterized the sorption-desorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-Nnitro-2-imidazolidinimine) and three of its metabolites, 1-[(6-chloro-3-pyridinyl)methyl]-2-imidazolidinone (imidacloprid-urea), 1-[(6-chloro-3-pyridinyl)methyl]-4,5-dihydro-1H-imidazol-2-amine (imidaclopridguanidine), and 1-[(6-chloro-3-pyridinyl)methyl]-1H-imidazol-2-amine (imidacloprid-guanidine-olefin), as a function of changing soil properties with depth in two profiles extending from the surface to a depth of 1.8 or 8 m. Sorption of each compound was highly variable and hysteretic in all cases. Normalizing the sorption coefficients (Kf) to the organic carbon or the clay content of the soil did not reduce the variability in sorption coefficients for any compound. These results illustrate the importance of evaluation of the sorption data used to predict potential mobility. Understanding the variability of soil properties and processes as a function of depth is necessary for accurate prediction of pesticide dissipation
A Comparison of Galaxy Merger History Observations and Predictions from Semi-Analytic Models
We present a detailed analysis of predicted galaxy-galaxy merger fractions
and rates in the Millennium simulation and compare these with the most up to
date observations of the same quantities up to z~3. We carry out our analysis
by considering the predicted merger history in the Millennium simulation within
a given time interval, as a function of stellar mass. This method, as opposed
to pair fraction counts, considers mergers that have already taken place, and
allows a more direct comparison with the observed rates and fractions measured
with the concentration-asymmetry-clumpiness (CAS) method. We examine the
evolution of the predicted merger fraction and rate in the Millennium
simulation for galaxies with stellar masses M_* ~ 10^9 - 10^12 M_sun. We find
that the predicted merger rates and fractions match the observations well for
galaxies with M_* > 10^11 M_sun at z<2, while significant discrepancies occur
at lower stellar masses, and at z>2 for M_* > 10^11 M_sun systems. At z>2 the
simulations underpredict the observed merger fractions by a factor of 4-10. The
shape of the predicted merger fraction and rate evolutions are similar to the
observations up to z~2, and peak at 1<z<2 in almost all mass bins. The
exception is the merger rate of galaxies with M_* > 10^11 M_sun. We discuss
possible reasons for these discrepancies, and compare different realisations of
the Millennium simulation to understand the effect of varying the physical
implementation of feedback. We conclude that the comparison is potentially
affected by a number of issues, including uncertainties in interpreting the
observations and simulations in terms of the assumed merger mass ratios and
merger time-scales. (abridged)Comment: 15 pages, 9 figures. References update
The dependence of AGN activity on stellar and halo mass in Semi-Analytic Models
AGN feedback is believed to play an important role in shaping a variety of
observed galaxy properties, as well as the evolution of their stellar masses
and star formation rates. In particular, in the current theoretical paradigm of
galaxy formation, AGN feedback is believed to play a crucial role in regulating
the levels of activity in galaxies, in relatively massive halos at low
redshift. Only in recent years, however, has detailed statistical information
on the dependence of galaxy activity on stellar mass, parent halo mass and
hierarchy has become available. In this paper, we compare the fractions of
galaxies belonging to different activity classes (star-forming, AGN and radio
active) with predictions from four different and independently developed
semi-analytical models. We adopt empirical relations to convert physical
properties into observables (H_alpha emission lines, OIII line strength and
radio power). We demonstrate that all models used in this study reproduce the
overall distributions of galaxies belonging to different activity classes as a
function of stellar mass and halo mass: star forming galaxies and the strongest
radio sources are preferentially associated with low-mass and high-mass
galaxies/halos respectively. However, model predictions differ from
observational measurements in a number of ways. All models used in our study
predict that almost every >1.e12 Msun dark matter halo and/or >1.e11 Msun
galaxy should host a bright radio source, while only a small fraction of
galaxies belong to this class in the data. In addition, radio brightness is
expected to depend strongly on the mass of the parent halo mass in the models,
while strong and weak radio galaxies are found in similar environments in data.
Our results highlight that the distribution of AGN as a function of stellar
mass provides one of the most promising discriminants between different gas
accretion schemes.Comment: 15 pages; 8 figures; 1 table; updated to match MNRAS accepted versio
Probing recent star formation with absorption-line strengths in hierarchical models and observations
Stellar population parameters derived from spectral line-strengths provide a
powerful probe of galaxy properties and formation histories. We implement the
machinery for extracting single-stellar-population-equivalent stellar
population parameters from synthetic spectra generated by a hierarchical galaxy
formation model. We find that the SSP-equivalent age is related to the
light-weighted age in a complicated fashion that reflects the influence of
recently-formed stars and is poorly correlated with the mass-weighted age. The
tendency for SSP-equivalent ages to be biased young means that archaeological
downsizing overstates the mass-weighted downsizing in age with mass. We find
that the SSP-equivalent metallicity closely tracks the mass- and light-weighted
metallicities, so that observed mass--metallicity relations for old galaxies
closely reflect the underlying trends. We construct mock catalogues of
early-type galaxies in a Coma cluster-sized halo and compare them directly to
observations of early-type galaxies in the Coma cluster. The similarity of the
SSP-equivalent ages in the observational samples and the mock catalogues gives
us confidence that the star-formation quenching implemented in the hierarchical
galaxy formation model produces roughly the correct amount of recent star
formation. The SSP-equivalent metallicities are however too low and have the
wrong slope as a function of velocity dispersion, and the SSP-equivalent ages
of the model galaxies may have an incorrect slope as a function of velocity
dispersion. (Abridged)Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Society. 17 page
The Degeneracy of Galaxy Formation Models
We develop a new formalism for modeling the formation and evolution of
galaxies within a hierarchical universe. Similarly to standard semi-analytical
models we trace galaxies inside dark-matter merger-trees. The formalism
includes treatment of feedback, star-formation, cooling, smooth accretion, gas
stripping in satellite galaxies, and merger-induced star bursts. However,
unlike in other models, each process is assumed to have an efficiency which
depends only on the host halo mass and redshift. This allows us to describe the
various components of the model in a simple and transparent way. By allowing
the efficiencies to have any value for a given halo mass and redshift, we can
easily encompass a large range of scenarios. To demonstrate this point, we
examine several different galaxy formation models, which are all consistent
with the observational data. Each model is characterized by a different unique
feature: cold accretion in low mass haloes, zero feedback, stars formed only in
merger-induced bursts, and shutdown of star-formation after mergers. Using
these models we are able to examine the degeneracy inherent in galaxy formation
models, and look for observational data that will help to break this
degeneracy. We show that the full distribution of star-formation rates in a
given stellar mass bin is promising in constraining the models. We compare our
approach in detail to the semi-analytical model of De Lucia & Blaizot. It is
shown that our formalism is able to produce a very similar population of
galaxies once the same median efficiencies per halo mass and redshift are being
used. We provide a public version of the model galaxies on our web-page, along
with a tool for running models with user-defined parameters. Our model is able
to provide results for a 62.5 h^{-1} Mpc box within just a few seconds.Comment: Accepted for publication in MNRAS. Fig 6 & 7 corrected. For the
project page which allows running your own model, see
http://www.mpa-garching.mpg.de/galform/sesam
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