32,402 research outputs found
Methods of household consumption measurement through surveys : experimental results from Tanzania
Consumption expenditure has long been the preferred measure of household living standards. However, accurate measurement is a challenge and household expenditure surveys vary widely across many dimensions, including the level of reporting, the length of the reference period, and the degree of commodity detail. These variations occur both across countries and also over time within countries. There is little current understanding of the implications of such changes for spatially and temporally consistent measurement of household consumption and poverty. A field experiment in Tanzania tests eight alternative methods to measure household consumption on a sample of 4,000 households. There are significant differences between consumption reported by the benchmark personal diary and other diary and recall formats. Under-reporting is particularly relevant in illiterate households and for urban respondents completing household diaries; recall modules measure lower consumption than a personal diary, with larger gaps among poorer households and households with more adult members. Variations in reporting accuracy by household characteristics are also discussed and differences in measured poverty as a result of survey design are explored. The study concludes with recommendations for methods of survey based consumption measurement in low-income countries.Consumption,Regional Economic Development,Rural Poverty Reduction,Poverty Lines
Time resolved spectroscopy of dust and gas from extrasolar planetesimals orbiting WD 1145+017
Multiple long and variable transits caused by dust from possibly
disintegrating asteroids were detected in light curves of WD 1145+017. We
present time-resolved spectroscopic observations of this target with QUCAM CCDs
mounted in the Intermediate dispersion Spectrograph and Imaging System at the
4.2-m William Herschel Telescope in two different spectral arms: the blue arm
covering 3800-4025 {\AA} and the red arm covering 7000-7430 {\AA}. When
comparing individual transits in both arms, our observations show with 20
{\sigma} significance an evident colour difference between the in- and
out-of-transit data of the order of 0.05-0.1 mag, where transits are deeper in
the red arm. We also show with > 6 {\sigma} significance that spectral lines in
the blue arm are shallower during transits than out-of-transit. For the
circumstellar lines it also appears that during transits the reduction in
absorption is larger on the red side of the spectral profiles. Our results
confirm previous findings showing the u'-band excess and a decrease in line
absorption during transits. Both can be explained by an opaque body blocking a
fraction of the gas disc causing the absorption, implying that the absorbing
gas is between the white dwarf and the transiting objects. Our results also
demonstrate the capability of EMCCDs to perform high-quality time resolved
spectroscopy of relatively faint targets.Comment: 9 pages, 5 figures. Accepted to MNRA
The Evolution of Quasar CIV and SiIV Broad Absorption Lines Over Multi-Year Time Scales
We investigate the variability of CIV 1549A broad absorption line (BAL)
troughs over rest-frame time scales of up to ~7 yr in 14 quasars at redshifts
z>2.1. For 9 sources at sufficiently high redshift, we also compare CIV and
SiIV 1400A absorption variation. We compare shorter- and longer-term
variability using spectra from up to four different epochs per source and find
complex patterns of variation in the sample overall. The scatter in the change
of absorption equivalent width (EW), Delta EW, increases with the time between
observations. BALs do not, in general, strengthen or weaken monotonically, and
variation observed over shorter (<months) time scales is not predictive of
multi-year variation. We find no evidence for asymmetry in the distribution of
Delta EW that would indicate that BALs form and decay on different time scales,
and we constrain the typical BAL lifetime to be >~30 yr. The BAL absorption for
one source, LBQS 0022+0150, has weakened and may now be classified as a
mini-BAL. Another source, 1235+1453, shows evidence of variable, blue continuum
emission that is relatively unabsorbed by the BAL outflow. CIV and SiIV BAL
shape changes are related in at least some sources. Given their high
velocities, BAL outflows apparently traverse large spatial regions and may
interact with parsec-scale structures such as an obscuring torus. Assuming BAL
outflows are launched from a rotating accretion disk, notable azimuthal
symmetry is required in the outflow to explain the relatively small changes
observed in velocity structure over times up to 7 yr
Matching pursuit-based compressive sensing in a wearable biomedical accelerometer fall diagnosis device
There is a significant high fall risk population, where individuals are susceptible to frequent falls and obtaining significant injury, where quick medical response and fall information are critical to providing efficient aid. This article presents an evaluation of compressive sensing techniques in an accelerometer-based intelligent fall detection system modelled on a wearable Shimmer biomedical embedded computing device with Matlab. The presented fall detection system utilises a database of fall and activities of daily living signals evaluated with discrete wavelet transforms and principal component analysis to obtain binary tree classifiers for fall evaluation. 14 test subjects undertook various fall and activities of daily living experiments with a Shimmer device to generate data for principal component analysis-based fall classifiers and evaluate the proposed fall analysis system. The presented system obtains highly accurate fall detection results, demonstrating significant advantages in comparison with the thresholding method presented. Additionally, the presented approach offers advantageous fall diagnostic information. Furthermore, transmitted data accounts for over 80% battery current usage of the Shimmer device, hence it is critical the acceleration data is reduced to increase transmission efficiency and in-turn improve battery usage performance. Various Matching pursuit-based compressive sensing techniques have been utilised to significantly reduce acceleration information required for transmission.Scopu
Magnetic nulls and super-radial expansion in the solar corona
Magnetic fields in the sun's outer atmosphere -- the corona -- control both
solar-wind acceleration and the dynamics of solar eruptions. We present the
first clear observational evidence of coronal magnetic nulls in off-limb
linearly polarized observations of pseudostreamers, taken by the Coronal
Multichannel Polarimeter (CoMP) telescope. These nulls represent regions where
magnetic reconnection is likely to act as a catalyst for solar activity. CoMP
linear-polarization observations also provide an independent, coronal proxy for
magnetic expansion into the solar wind, a quantity often used to parameterize
and predict the solar wind speed at Earth. We introduce a new method for
explicitly calculating expansion factors from CoMP coronal linear-polarization
observations, which does not require photospheric extrapolations. We conclude
that linearly-polarized light is a powerful new diagnostic of critical coronal
magnetic topologies and the expanding magnetic flux tubes that channel the
solar wind
A ground-based NUV secondary eclipse observation of KELT-9b
KELT-9b is a recently discovered exoplanet with a 1.49 d orbit around a
B9.5/A0-type star. The unparalleled levels of UV irradiation it receives from
its host star put KELT-9b in its own unique class of ultra-hot Jupiters, with
an equilibrium temperature > 4000 K. The high quantities of dissociated
hydrogen and atomic metals present in the dayside atmosphere of KELT-9b bear
more resemblance to a K-type star than a gas giant. We present a single
observation of KELT-9b during its secondary eclipse, taken with the Wide Field
Camera on the Isaac Newton Telescope (INT). This observation was taken in the
U-band, a window particularly sensitive to Rayleigh scattering. We do not
detect a secondary eclipse signal, but our 3 upper limit of 181 ppm on
the depth allows us to constrain the dayside temperature of KELT-9b at
pressures of ~30 mbar to 4995 K (3). Although we can place an
observational constraint of 0.14, our models suggest that the actual
value is considerably lower than this due to H opacity. This places KELT-9b
squarely in the albedo regime populated by its cooler cousins, almost all of
which reflect very small components of the light incident on their daysides.
This work demonstrates the ability of ground-based 2m-class telescopes like the
INT to perform secondary eclipse studies in the NUV, which have previously only
been conducted from space-based facilities.Comment: Accepted in ApJL. 7 pages, 3 figure
The resistance experiments: Morality, authority and obedience in Stanley Milgram's account
The paper seeks to re‐conceptualize Stanley Milgram's (in)famous experiments on willing obedience by drawing solely on Milgram's own contemporary account. It identifies a substantial incongruence between the findings Milgram presented (i.e., his description of the experiments) and the meaning he imputed to them (i.e., his interpretation of the exper iments). It argues that instead of operationalizing the concepts he claimed to operationalize – legitimate authority, embodied morality and willing obedience –, Milgram's description suggests that the operative forces in the experiments were an illegitimate authority and acts which in effect collude with that authority. As a result, the paper concludes that what the experimental findings represented was not so much obedience out of choice, but out of coercion. Thus, the paper seeks to redirect the conceptual‐moral focus of the findings from the participants who “shockingly” obeyed to those who managed to resist the coercive force of the total experimental situation
Uncovering the topology of configuration space networks
The configuration space network (CSN) of a dynamical system is an effective
approach to represent the ensemble of configurations sampled during a
simulation and their dynamic connectivity. To elucidate the connection between
the CSN topology and the underlying free-energy landscape governing the system
dynamics and thermodynamics, an analytical soluti on is provided to explain the
heavy tail of the degree distribution, neighbor co nnectivity and clustering
coefficient. This derivation allows to understand the universal CSN network
topology observed in systems ranging from a simple quadratic well to the native
state of the beta3s peptide and a 2D lattice heteropolymer. Moreover CSN are
shown to fall in the general class of complex networks describe d by the
fitness model.Comment: 6 figure
Gravitational hydrodynamics of large scale structure formation
The gravitational hydrodynamics of the primordial plasma with neutrino hot
dark matter is considered as a challenge to the bottom-up cold dark matter
paradigm. Viscosity and turbulence induce a top-down fragmentation scenario
before and at decoupling. The first step is the creation of voids in the
plasma, which expand to 37 Mpc on the average now. The remaining matter clumps
turn into galaxy clusters. Turbulence produced at expanding void boundaries
causes a linear morphology of 3 kpc fragmenting protogalaxies along vortex
lines. At decoupling galaxies and proto-globular star clusters arise; the
latter constitute the galactic dark matter halos and consist themselves of
earth-mass H-He planets. Frozen planets are observed in microlensing and
white-dwarf-heated ones in planetary nebulae. The approach also explains the
Tully-Fisher and Faber-Jackson relations, and cosmic microwave temperature
fluctuations of micro-Kelvins.Comment: 6 pages, no figure
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