163 research outputs found
Ante-Autobiography and the Archive of Childhood
This essay examines the concept of children’s autobiography via several autobiographical extracts
written by the author as a child. Although only a small proportion of people will compose and
publish a full-length autobiography, almost everyone will, inadvertently, produce an archive of
the self, made from public records and private documents. Here, such works are seen as providing
access to writing both about and by children. The essay explores the ethics and poetics of
children’s writing via the key debates in life writing; in particular, the dynamic relationship
between adults and children, both as distinct stages of life and dual parts of one autobiographical
identity. The term “ante-autobiography” is coined to refer to these texts which come before or
instead of a full-length narrative. They are not read as less than or inadequate versions of
autobiography, but rather as transgressive and challenging to chronological notions of the genre
The Changing Nature of Poverty
Since the beginning of the War on Poverty, the poverty rate has fluctuated widely, and at the same time the poverty population has undergone many changes, some mirroring the changing stereotypes of the poor and others less pronounced than the changing stereotypes would lead us to believe. A feminization of poverty has occurred, with many more of the poor now in households headed by women. Interestingly, aging of the poverty population has not occurred despite growth in the elderly segment of the overall population. Concerning turnover in the poverty population, we find that despite poverty theories emphasizing persistence, recurrent poverty is relatively rare and poverty is not generally passed from one generation to the next. Poverty prevention has come from both economic growth and government transfers; however, inequality in economic growth has contributed to poverty. With the proportion of elderly and female- headed households likely to continue at a high level into the future, poverty rates are also likely to remain high unless government transfers are increased.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66979/2/10.1177_000271628547900103.pd
XMM-Newton observations of the Galactic Supernova Remnant CTB 109 (G109.1-1.0)
We present the analysis of the X-ray Multi-Mirror Mission (XMM-Newton)
European Photon Imaging Camera (EPIC) data of the Galactic supernova remnant
(SNR) CTB 109 (G109.1-1.0). CTB 109 is associated with the anomalous X-ray
pulsar (AXP) 1E 2259+586 and has an unusual semi-circular morphology in both
the X-ray and the radio, and an extended X-ray bright interior region known as
the `Lobe'. The deep EPIC mosaic image of the remnant shows no emission towards
the west where a giant molecular cloud complex is located. No morphological
connection between the Lobe and the AXP is found. We find remarkably little
spectral variation across the remnant given the large intensity variations. All
spectra of the shell and the Lobe are well fitted by a single-temperature
non-equilibrium ionization model for a collisional plasma with solar abundances
(kT = 0.5 - 0.7 keV, tau = n_e t = 1 - 4 x 10^11 s cm^-3, N_H = 5 - 7 x 10^21
cm^-2). There is no indication of nonthermal emission in the Lobe or the shell.
We conclude that the Lobe originated from an interaction of the SNR shock wave
with an interstellar cloud. Applying the Sedov solution for the undisturbed
eastern part of the SNR, and assuming full equilibration between the electrons
and ions behind the shock front, the SNR shock velocity is derived as v_s = 720
+/- 60 km s^-1, the remnant age as t = (8.8 +/- 0.9) x 10^3 d_3 yr, the initial
energy as E_0 = (7.4 +/- 2.9) x 10^50 d_3^2.5 ergs, and the pre-shock density
of the nuclei in the ambient medium as n_0 = (0.16 +/- 0.02) d_3^-0.5 cm^-3, at
an assumed distance of D = 3.0 d_3 kpc. Assuming CTB 109 and 1E 2259+586 are
associated, these values constrain the age and the environment of the
progenitor of the SNR and the pulsar.Comment: Accepted for publication in ApJ. 9 figures. Figs. 1 + 2 are in color
(fig1.jpg, fig2.jpg
Deep soils modify environmental consequences of increased nitrogen fertilizer use in intensifying Amazon agriculture
Agricultural intensification offers potential to grow more food while reducing the conversion of native ecosystems to croplands. However, intensification also risks environmental degradation through emissions of the greenhouse gas nitrous oxide (N2O) and nitrate leaching to ground and surface waters. Intensively-managed croplands and nitrogen (N) fertilizer use are expanding rapidly in tropical regions. We quantified fertilizer responses of maize yield, N2O emissions, and N leaching in an Amazon soybean-maize double-cropping system on deep, highly-weathered soils in Mato Grosso, Brazil. Application of N fertilizer above 80 kg N ha−1 yr−1 increased maize yield and N2O emissions only slightly. Unlike experiences in temperate regions, leached nitrate accumulated in deep soils with increased fertilizer and conversion to cropping at N fertilization rates \u3e80 kg N ha−1, which exceeded maize demand. This raises new questions about the capacity of tropical agricultural soils to store nitrogen, which may determine when and how much nitrogen impacts surface waters
Economic crisis and the construction of a neo-liberal regulatory regime in Korea
A consistent theme of the literature on the ontology of the 1997 South Korean crisis is the key role played by regulatory failures and the growing weakness of the state. This paper seeks to briefly highlight both the insights and the limitations of this approach to understanding the crisis. Having done so, we shall set out the argument that the crisis created an opportunity for reformist Korean élites to advance their longstanding, but previously frustrated, project to create a comprehensive unambiguously neo-liberal regulatory regime. This paper will also seek to highlight the implications of our reading of the development of the Korean political economy for broader debates on economic liberalisation, crisis and the future of the developmental state
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Aircraft and ground measurements of dust aerosols over the west African coast in summer 2015 during ICE-D and AER-D
During the summertime, dust from the Sahara can be efficiently transported westwards within the Saharan air layer (SAL). This can lead to high aerosol loadings being observed above a relatively clean marine boundary layer (MBL) in the tropical Atlantic Ocean. These dust layers can impart significant radiative effects through strong visible and IR light absorption and scattering, and can also have indirect impacts by altering cloud properties. The processing of the dust aerosol can result in changes in both direct and indirect radiative effects, leading to significant uncertainty in climate prediction in this region. During August 2015, measurements of aerosol and cloud properties were conducted off the coast of west Africa as part of the Ice in Cloud Experiment - Dust (ICE-D) and AERosol properties - Dust (AER-D) campaigns. Observations were obtained over a 4-week period using the UK Facility for Atmospheric Airborne Measurements (FAAM) BAe 146 aircraft based on Santiago Island, Cabo Verde. Ground-based observations were collected from Praia (14∘57′ N, 23∘29′ W; 100 m a.s.l.), also located on Santiago Island. The dust in the SAL was mostly sampled in situ at altitudes of 2-4 km, and the potential dust age was estimated by backward trajectory analysis. The particle mass concentration (at diameter d = 0.1-20 µm) decreased with transport time. Mean effective diameter (Deff) for supermicron SAL dust (d = 1-20 µm) was found to be 5-6 µm regardless of dust age, whereas submicron Deff (d = 0.1-1 µm) showed a decreasing trend with longer transport. For the first time, an airborne laser-induced incandescence instrument (the single particle soot photometer - SP2) was deployed to measure the hematite content of dust. For the Sahel-influenced dust in the SAL, the observed hematite mass fraction of dust (FHm) was found to be anti-correlated with the single scattering albedo (SSA, λ = 550 nm, for particles d < 2.5 µm); as potential dust age increased from 2 to 7 days, FHm increased from 2.5 to 4.5 %, SSA decreased from 0.97 to 0.93 and the derived imaginary part (k) of the refractive index at 550 nm increased from 0.0015 to 0.0035. However, the optical properties of Sahara-influenced plumes (not influenced by the Sahel) were independent of dust age and hematite content with SSA ∼ 0.95 and k ∼ 0.0028. This indicates that the absorbing component of dust may be source dependent, or that gravitational settling of larger particles may lead to a higher fraction of more absorbing clay-iron aggregates at smaller sizes. Mie calculation using the measured size distribution and size-resolved refractive indices of the absorbing components (black carbon and hematite) reproduces the measured SSA to within ±0.02 for SAL dust by assuming a goethite ∕ hematite mass ratio of 2. Overall, hematite and goethite constituted 40-80 % of the absorption for particles d < 2.5 µm, and black carbon (BC) contributed 10-37 %. This highlights the importance of size-dependent composition in determining the optical properties of dust and also the contribution from BC within dust plumes
Motor Preparatory Activity in Posterior Parietal Cortex is Modulated by Subjective Absolute Value
For optimal response selection, the consequences associated with behavioral success or failure must be appraised. To determine how monetary consequences influence the neural representations of motor preparation, human brain activity was scanned with fMRI while subjects performed a complex spatial visuomotor task. At the beginning of each trial, reward context cues indicated the potential gain and loss imposed for correct or incorrect trial completion. FMRI-activity in canonical reward structures reflected the expected value related to the context. In contrast, motor preparatory activity in posterior parietal and premotor cortex peaked in high “absolute value” (high gain or loss) conditions: being highest for large gains in subjects who believed they performed well while being highest for large losses in those who believed they performed poorly. These results suggest that the neural activity preceding goal-directed actions incorporates the absolute value of that action, predicated upon subjective, rather than objective, estimates of one's performance
Efficient light-emitting diodes based on nanocrystalline perovskite in a dielectric polymer matrix.
Electroluminescence in light-emitting devices relies on the encounter and radiative recombination of electrons and holes in the emissive layer. In organometal halide perovskite light-emitting diodes, poor film formation creates electrical shunting paths, where injected charge carriers bypass the perovskite emitter, leading to a loss in electroluminescence yield. Here, we report a solution-processing method to block electrical shunts and thereby enhance electroluminescence quantum efficiency in perovskite devices. In this method, a blend of perovskite and a polyimide precursor dielectric (PIP) is solution-deposited to form perovskite nanocrystals in a thin-film matrix of PIP. The PIP forms a pinhole-free charge-blocking layer, while still allowing the embedded perovskite crystals to form electrical contact with the electron- and hole-injection layers. This modified structure reduces nonradiative current losses and improves quantum efficiency by 2 orders of magnitude, giving an external quantum efficiency of 1.2%. This simple technique provides an alternative route to circumvent film formation problems in perovskite optoelectronics and offers the possibility of flexible and high-performance light-emitting displays.The authors acknowledge funding from the Gates Cambridge Trust, the Singapore National Research Foundation (Energy Innovation Programme Office), the KACST-Cambridge University Joint Centre of Excellence, the Royal Society/Sino-British Fellowship Trust, and the Engineering and Physical Sciences Research Council, UK. We also thank Dr. Alessandro Sepe for helpful discussions of the XRD data.This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/acs.nanolett.5b0023
A highly magnified candidate for a young galaxy seen when the Universe was 500 Myrs old
The early Universe at redshift z\sim6-11 marks the reionization of the
intergalactic medium, following the formation of the first generation of stars.
However, those young galaxies at a cosmic age of \lesssim 500 million years
(Myr, at z \gtrsim 10) remain largely unexplored as they are at or beyond the
sensitivity limits of current large telescopes. Gravitational lensing by galaxy
clusters enables the detection of high-redshift galaxies that are fainter than
what otherwise could be found in the deepest images of the sky. We report the
discovery of an object found in the multi-band observations of the cluster
MACS1149+22 that has a high probability of being a gravitationally magnified
object from the early universe. The object is firmly detected (12 sigma) in the
two reddest bands of HST/WFC3, and not detected below 1.2 {\mu}m, matching the
characteristics of z\sim9 objects. We derive a robust photometric redshift of z
= 9.6 \pm 0.2, corresponding to a cosmic age of 490 \pm 15Myr (i.e., 3.6% of
the age of the Universe). The large number of bands used to derive the redshift
estimate make it one of the most accurate estimates ever obtained for such a
distant object. The significant magnification by cluster lensing (a factor of
\sim15) allows us to analyze the object's ultra-violet and optical luminosity
in its rest-frame, thus enabling us to constrain on its stellar mass,
star-formation rate and age. If the galaxy is indeed at such a large redshift,
then its age is less than 200 Myr (at the 95% confidence level), implying a
formation redshift of zf \lesssim 14. The object is the first z>9 candidate
that is bright enough for detailed spectroscopic studies with JWST,
demonstrating the unique potential of galaxy cluster fields for finding highly
magnified, intrinsically faint galaxies at the highest redshifts.Comment: Submitted to the Nature Journal. 39 Pages, 13 figure
Cluster Lenses
Clusters of galaxies are the most recently assembled, massive, bound
structures in the Universe. As predicted by General Relativity, given their
masses, clusters strongly deform space-time in their vicinity. Clusters act as
some of the most powerful gravitational lenses in the Universe. Light rays
traversing through clusters from distant sources are hence deflected, and the
resulting images of these distant objects therefore appear distorted and
magnified. Lensing by clusters occurs in two regimes, each with unique
observational signatures. The strong lensing regime is characterized by effects
readily seen by eye, namely, the production of giant arcs, multiple-images, and
arclets. The weak lensing regime is characterized by small deformations in the
shapes of background galaxies only detectable statistically. Cluster lenses
have been exploited successfully to address several important current questions
in cosmology: (i) the study of the lens(es) - understanding cluster mass
distributions and issues pertaining to cluster formation and evolution, as well
as constraining the nature of dark matter; (ii) the study of the lensed objects
- probing the properties of the background lensed galaxy population - which is
statistically at higher redshifts and of lower intrinsic luminosity thus
enabling the probing of galaxy formation at the earliest times right up to the
Dark Ages; and (iii) the study of the geometry of the Universe - as the
strength of lensing depends on the ratios of angular diameter distances between
the lens, source and observer, lens deflections are sensitive to the value of
cosmological parameters and offer a powerful geometric tool to probe Dark
Energy. In this review, we present the basics of cluster lensing and provide a
current status report of the field.Comment: About 120 pages - Published in Open Access at:
http://www.springerlink.com/content/j183018170485723/ . arXiv admin note:
text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author
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