1,374 research outputs found
Informal urbanism and the Internet of Things: Reliability, trust and the reconfiguration of infrastructure
Of the build out of humanity predicted up to the end of the century, a substantial portion will occur within informal urban settlements â areas characterised by poor access to infrastructure and services. There is a pressing need to better understand how and with what implications the growing proliferation of Internet of Things (IoT) technologies, as a component of smart urbanism, are being applied to address the challenges of these areas. The following paper addresses this research gap, showing how IoT technology is reconfiguring trust within water and energy infrastructures in Nairobi. We apply work on informal urban infrastructures and smart urbanism to three case studies, producing novel insights into how IoT technologies reconfigure connections between users, providers and infrastructures. This reconfiguration of trust smooths chronic infrastructural uncertainties and generates reliability within informal settlements and, in doing so, leads to increased personal economies. We conclude by considering how these examples provide insights into the implications of IoT for everyday urbanisms in informal settlements and how these insights relate to global smart city debates more widely
Simulations of the Population of Centaurs I: The Bulk Statistics
Large-scale simulations of the Centaur population are carried out. The
evolution of 23328 particles based on the orbits of 32 well-known Centaurs is
followed for up to 3 Myr in the forward and backward direction under the
influence of the 4 massive planets. The objects exhibit a rich variety of
dynamical behaviour with half-lives ranging from 540 kyr (1996 AR20) to 32 Myr
(2000 FZ53). The mean half-life of the entire sample of Centaurs is 2.7 Myr.
The data are analyzed using a classification scheme based on the controlling
planets at perihelion and aphelion, previously given in Horner et al (2003).
Transfer probabilities are computed and show the main dynamical pathways of the
Centaur population. The total number of Centaurs with diameters larger than 1
km is estimated as roughly 44300, assuming an inward flux of one new
short-period comet every 200 yrs. The flux into the Centaur region from the
Edgeworth-Kuiper belt is estimated to be 1 new object every 125 yrs. Finally,
the flux from the Centaur region to Earth-crossing orbits is 1 new
Earth-crosser every 880 yrsComment: 15 pages, 2 figures, MNRAS in pres
A long-lived horseshoe companion to the Earth
We present a dynamical investigation of a newly found asteroid, 2010 SO16,
and the discovery that it is a horseshoe companion of the Earth. The object's
absolute magnitude (H=20.7) makes this the largest object of its type known
to-date. By carrying out numerical integrations of dynamical clones, we find
that (a) its status as a horseshoe is secure given the current accuracy of its
ephemeris, and (b) the time spent in horseshoe libration with the Earth is
several times 10^5 yr, two orders of magnitude longer than determined for other
horseshoe asteroids of the Earth. Further, using a model based on Hill's
approximation to the three-body problem, we show that, apart from the low
eccentricity which prevents close encounters with other planets or the Earth
itself, its stability can be attributed to the value of its Jacobi constant far
from the regime that allows transitions into other coorbital modes or escape
from the resonance altogether. We provide evidence that the eventual escape of
the asteroid from horseshoe libration is caused by the action of planetary
secular perturbations and the stochastic evolution of the eccentricity. The
questions of its origin and the existence of as-yet-undiscovered co-orbital
companions of the Earth are discussed.Comment: Accepted in MNRAS; 6 pages, 3 figures, 2 table
Release of Pen-reared Bobwhites: Potential Consequences to the Genetic Integrity of Resident Wild Populations
In response to low encounter rates with wild northern bobwhite (Colinus virginianus; hereafter bobwhite) during bird dog field trials at Ames Plantation in Tennessee, a large-scale release program of pen-reared bobwhites was implemented in fall 2002. To evaluate genetic effects of pen-reared releases on wild populations, we monitored survival of pen-reared and wild bobwhites from fall release of pen-reared bobwhites through the breeding season and collected feather samples from wild, pen-reared, and free-ranging juvenile bobwhites following the first breeding season after the initial release. We used genotypes from 6 polymorphic microsatellite loci to measure genetic diversity and conduct population assignment tests. Wild bobwhites experienced greater fallspring and annual survival than pen-reared bobwhites; however, pen-reared bobwhites experienced greater fall-spring and annual survival than reported in most other studies. Genetic diversity, number of alleles, and allelic richness were greatest in the wild, intermediate in the F1 generation, and lowest in the pen-reared populations. Likelihood analysis and cluster analysis indicated 20.4% and 33.6%, respectively, of juveniles captured after the first breeding season following release were ambiguous in population assignment; suggesting successful reproduction between wild and pen-reared individuals. These results suggest that large-scale releases of pen-reared bobwhite may result in negative impacts on genetic integrity of resident wild populations
Two Massive, Low-Luminosity Cores Toward Infrared Dark Clouds
This article presents high-resolution interferometric mosaics in the 850
micron waveband of two massive, quiescent infrared dark clouds. The two clouds
were chosen based on their likelihood to represent environments preceding the
formation of massive stars. The brightest compact sources detected in each
cloud have masses of approximately 110 and 60 solar masses with radii < 0.1 pc,
implying mean volume densities of approximately 1 million particles per cubic
centimeter and mean column densities of about 1 gram per square centimeter.
Supplementary data show these cores to be cold and inactive. Low upper limits
to their bolometric luminosities and temperatures place them at a very early
stage of evolution while current models of massive star formation suggest they
have the potential to form massive stars.Comment: 6 pages, 5 figures. Accepted for publication by the Astrophysical
Journa
A Mid-Infrared Census of Star Formation Activity in Bolocam Galactic Plane Survey Sources
We present the results of a search for mid-infrared signs of star formation
activity in the 1.1 mm sources in the Bolocam Galactic Plane Survey (BGPS). We
have correlated the BGPS catalog with available mid-IR Galactic plane catalogs
based on the Spitzer Space Telescope GLIMPSE legacy survey and the Midcourse
Space Experiment (MSX) Galactic plane survey. We find that 44% (3,712 of 8,358)
of the BGPS sources contain at least one mid-IR source, including 2,457 of
5,067 (49%) within the area where all surveys overlap (10 deg < l < 65 deg).
Accounting for chance alignments between the BGPS and mid-IR sources, we
conservatively estimate that 20% of the BPGS sources within the area where all
surveys overlap show signs of active star formation. We separate the BGPS
sources into four groups based on their probability of star formation activity.
Extended Green Objects (EGOs) and Red MSX Sources (RMS) make up the highest
probability group, while the lowest probability group is comprised of
"starless" BGPS sources which were not matched to any mid-IR sources. The mean
1.1 mm flux of each group increases with increasing probability of active star
formation. We also find that the "starless" BGPS sources are the most compact,
while the sources with the highest probability of star formation activity are
on average more extended with large skirts of emission. A subsample of 280 BGPS
sources with known distances demonstrates that mass and mean H_2 column density
also increase with probability of star formation activity.Comment: 20 pages, 12 figures, 3 tables. Accepted for publication in ApJ. Full
Table 2 will be available online through Ap
Non-traumatic Arm, Neck, and Shoulder Complaints in General Practice: Incidence, Course and Management
Non-traumatic complaints of arm, neck, and shoulder are common and can result in functional limitations in daily life and may sometimes lead to sickness absence. Reported symptoms are e.g. pain, tingling, stiffness, numbness, loss of hand coordination. When seeking medical care for these complaints, the general practitioner (GP) is usually the first person to consult. This thesis studies patients who consult their GP with a new non-traumatic complaint of arm, neck or shoulder, with a focus on incidence, course and management.
The incidence study showed that a fulltime GP is consulted about 3 times every week for a new non-traumatic complaint of arm, neck, or shoulder, most frequently located at neck or shoulder.
Six months after the first consultation with their GP, 46% of the patients in the cohort study reported no recovery. Next to several complaint specific variables, the psychosocial variables little social support and high score on somatization were predicitve of non-recovery at 6 months.
Management upto 6 months after the first consultation most frequently consisted of prescribed analgesics and referral for physiotherapy. Specific and non-specific diagnostic subgroups differed in the frequency that corticosteroid injections were applied, and referrals to physiotherapy and to a medical specialist.
In addition variables associated with five common management options within a few weeks after the first consultation were evaluated. Overall, besides diagnosis, most frequently long duration of complaints, more functional limitations but also several GP characteristics were associated with the application of a treatment option in non-traumatic arm, neck and shoulder complaints
A sensitive search for CO J=1-0 emission in 4C 41.17: high-excitation molecular gas at z=3.8
We report sensitive imaging observations of the CO J=1-0 line emission in the
powerful high-redshift radio galaxy 4C 41.17 (z=3.8) with the NRAO Very Large
Array (VLA), conducted in order to detect the large concomitant H_2 gas
reservoir recently unveiled in this system by De Breuck et al (2005) via the
emission of the high excitation J=4-3 line. Our observations fail to detect the
J=1-0 line but yield sensitive lower limits on the R_43=(4-3)/(1-0) brightness
temperature ratio of R_43 ~ 0.55 - >1.0 for the bulk of the H_2 gas mass. Such
high ratios are typical of the high-excitation molecular gas phase ``fueling''
the star formation in local starbursts, but quite unlike these objects, much of
the molecular gas in 4C 41.17 seems to be in such a state, and thus
participating in the observed starburst episode. The widely observed and unique
association of highly excited molecular gas with star forming sites allows CO
line emission with large (high-J)/(low-J) intensity ratios to serve as an
excellent ``marker'' of the spatial distribution of star formation in distant
dust-obscured starbursts, unaffected by extinction.Comment: 7 Pages including 8 PostScript figures. Accepted for publication in
Astronomy & Astrophysic
Reading ads, reading the world
This paper challenges the reductive notion of children as âefferent' readers who learn to decode written language in order to âtake awayâ knowledge. This anachronistic idea has become entrenched in current UK curriculum and education policy. However, it is well established that decoding letters and sounds is only one aspect of reading, that reading is cultural and that learning to read, not only words but also images and sounds, develops children's comprehension and criticality. With this in mind, I seek to share a process through which children and young people were able to develop as readers with a particular focus on the reading of media texts. I present an account of media education activity which focused on the way children read media texts, in the classroom. I suggest that with appropriate pedagogic and conceptual tools children develop as critical, cultural and collaborative readers of words, images, sounds and texts and thereby of the world
Exploring High Aspect Ratio Gold Nanotubes as Cytosolic Agents: Structural Engineering and Uptake into Mesothelioma Cells.
The generation of effective and safe nanoagents for biological applications requires their physicochemical characteristics to be tunable, and their cellular interactions to be well characterized. Here, the controlled synthesis is developed for preparing high-aspect ratio gold nanotubes (AuNTs) with tailorable wall thickness, microstructure, composition, and optical characteristics. The modulation of optical properties generates AuNTs with strong near infrared absorption. Surface modification enhances dispersibility of AuNTs in aqueous media and results in low cytotoxicity. The uptake and trafficking of these AuNTs by primary mesothelioma cells demonstrate their accumulation in a perinuclear distribution where they are confined initially in membrane-bound vesicles from which they ultimately escape to the cytosol. This represents the first study of the cellular interactions of high-aspect ratio 1D metal nanomaterials and will facilitate the rational design of plasmonic nanoconstructs as cytosolic nanoagents for potential diagnosis and therapeutic applications.BLF-Papworth Fellowship from the British Lung Foundation and the Victor Dahdaleh Foundation
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