727 research outputs found
On Intergenerational Transmission of Reading Habits in Italy: Is a Good Example the Best Sermon?
The intergenerational transmission of preference and attitudes has been less investigated in the literature than the intergenerational transmission of education and income. Using the Italian Time Use Survey (2002-2003) conducted by ISTAT, we analyse the intergenerational transmission of reading habits: are children more likely to allocate time to studying and reading when they observe their parents doing the same activity? The intergeneration transmission of attitudes towards studying and reading can be explained by both cultural and educational transmission from parents to children and by imitating behaviours. The latter channel is of particular interest, since it entails a direct influence parents may have on child’s preference formation through their role model, and it opens the scope for active policies aimed at promoting good parents’ behaviours. We follow two fundamental approaches to estimation: a “long run” model, consisting of OLS intergenerational type regressions for the reading habit, and “short run” household fixed effect models, where we aim at identifying the impact of the role model exerted by parents, exploiting different exposure of sibling to parents’ example within the same household. Our long run results show that children are more likely to read and study when they live with parents that are used to read. Mothers seem to be more important than fathers in this type of intergenerational transmission. Moreover, the short run analysis shows that there is an imitation effect: in the day of the survey children are more likely to read after they saw either the mother or the father reading.
NIKEL: Electronics and data acquisition for kilopixels kinetic inductance camera
A prototype of digital frequency multiplexing electronics allowing the real
time monitoring of microwave kinetic inductance detector (MKIDs) arrays for
mm-wave astronomy has been developed. Thanks to the frequency multiplexing, it
can monitor simultaneously 400 pixels over a 500 MHz bandwidth and requires
only two coaxial cables for instrumenting such a large array. The chosen
solution and the performances achieved are presented in this paper.Comment: 21 pages, 14 figure
Electronics and data acquisition demonstrator for a kinetic inductance camera
A prototype of digital frequency multiplexing electronics allowing the real
time monitoring of kinetic inductance detector (KIDs) arrays for mm-wave
astronomy has been developed. It requires only 2 coaxial cables for
instrumenting a large array. For that, an excitation comb of frequencies is
generated and fed through the detector. The direct frequency synthesis and the
data acquisition relies heavily on a large FPGA using parallelized and
pipelined processing. The prototype can instrument 128 resonators (pixels) over
a bandwidth of 125 MHz. This paper describes the technical solution chosen, the
algorithm used and the results obtained
In-situ measurement of the permittivity of helium using microwave NbN resonators
By measuring the electrical transport properties of superconducting NbN
quarter-wave resonators in direct contact with a helium bath, we have
demonstrated a high-speed and spatially sensitive sensor for the permittivity
of helium. In our implementation a mm sensing volume is
measured with a bandwidth of 300 kHz in the temperature range 1.8 to 8.8 K. The
minimum detectable change of the permittivity of helium is calculated to be
/Hz with a sensitivity of order
/Hz easily achievable. Potential applications
include operation as a fast, localized helium thermometer and as a transducer
in superfluid hydrodynamic experiments.Comment: 4 pages, 3 figure
Niobium Silicon alloys for Kinetic Inductance Detectors
We are studying the properties of Niobium Silicon amorphous alloys as a
candidate material for the fabrication of highly sensitive Kinetic Inductance
Detectors (KID), optimized for very low optical loads. As in the case of other
composite materials, the NbSi properties can be changed by varying the relative
amounts of its components. Using a NbSi film with T_c around 1 K we have been
able to obtain the first NbSi resonators, observe an optical response and
acquire a spectrum in the band 50 to 300 GHz. The data taken show that this
material has very high kinetic inductance and normal state surface resistivity.
These properties are ideal for the development of KID. More measurements are
planned to further characterize the NbSi alloy and fully investigate its
potential.Comment: Accepted for publication on Journal of Low Temperature Physics.
Proceedings of the LTD15 conference (Caltech 2013
Development of Lumped Element Kinetic Inductance Detectors for NIKA
Lumped-element kinetic inductance detectors(LEKIDs) have recently shown
considerable promise as direct absorption mm-wavelength detectors for
astronomical applications. One major research thrust within the N\'eel Iram
Kids Array (NIKA) collaboration has been to investigate the suitability of
these detectors for deployment at the 30-meter IRAM telescope located on Pico
Veleta in Spain. Compared to microwave kinetic inductance detectors (MKID),
using quarter wavelength resonators, the resonant circuit of a LEKID consists
of a discrete inductance and capacitance coupled to a feedline. A high and
constant current density distribution in the inductive part of these resonators
makes them very sensitive. Due to only one metal layer on a silicon substrate,
the fabrication is relatively easy. In order to optimize the LEKIDs for this
application, we have recently probed a wide variety of individual resonator and
array parameters through simulation and physical testing. This included
determining the optimal feed-line coupling, pixel geometry, resonator
distribution within an array (in order to minimize pixel cross-talk), and
resonator frequency spacing. Based on these results, a 144-pixel Aluminum array
was fabricated and tested in a dilution fridge with optical access, yielding an
average optical NEP of ~2E-16 W/Hz^1/2 (best pixels showed NEP = 6E-17 W/Hz^1/2
under 4-8 pW loading per pixel). In October 2010 the second prototype of LEKIDs
has been tested at the IRAM 30 m telescope. A new LEKID geometry for 2
polarizations will be presented. Also first optical measurements of a titanium
nitride array will be discussed.Comment: 5 pages, 12 figures; ISSTT 2011 Worksho
Bi-layer Kinetic Inductance Detectors for space observations between 80-120 GHz
We have developed Lumped Element Kinetic Inductance Detectors (LEKID)
sensitive in the frequency band from 80 to 120~GHz. In this work, we take
advantage of the so-called proximity effect to reduce the superconducting gap
of Aluminium, otherwise strongly suppressing the LEKID response for frequencies
smaller than 100~GHz. We have designed, produced and optically tested various
fully multiplexed arrays based on multi-layers combinations of Aluminium (Al)
and Titanium (Ti). Their sensitivities have been measured using a dedicated
closed-circle 100 mK dilution cryostat and a sky simulator allowing to
reproduce realistic observation conditions. The spectral response has been
characterised with a Martin-Puplett interferometer up to THz frequencies, and
with a resolution of 3~GHz. We demonstrate that Ti-Al LEKID can reach an
optical sensitivity of about ~ (best pixel), or
~ when averaged over the whole array. The optical
background was set to roughly 0.4~pW per pixel, typical for future space
observatories in this particular band. The performance is close to a
sensitivity of twice the CMB photon noise limit at 100~GHz which drove the
design of the Planck HFI instrument. This figure remains the baseline for the
next generation of millimetre-wave space satellites.Comment: 7 pages, 9 figures, submitted to A&
NIKEL_AMC: Readout electronics for the NIKA2 experiment
The New Iram Kid Arrays-2 (NIKA2) instrument has recently been installed at
the IRAM 30 m telescope. NIKA2 is a state-of-art instrument dedicated to
mm-wave astronomy using microwave kinetic inductance detectors (KID) as
sensors. The three arrays installed in the camera, two at 1.25 mm and one at
2.05 mm, feature a total of 3300 KIDs. To instrument these large array of
detectors, a specifically designed electronics, composed of 20 readout boards
and hosted in three microTCA crates, has been developed. The implemented
solution and the achieved performances are presented in this paper. We find
that multiplexing factors of up to 400 detectors per board can be achieved with
homogeneous performance across boards in real observing conditions, and a
factor of more than 3 decrease in volume with respect to previous generations.Comment: 21 pages; 16 figure
Ultrasound and cone beam CT fusion for liver ablation : technical note
Purpose: To assess the feasibility of fusion imaging between intraprocedural ultrasound (US) and contrast-enhanced cone-beam CT (CBCT) for small (< 2 cm) hepatocellular carcinoma (HCC). Materials and methods: Six patients (five males, one female, age range 58\u201380, mean 69 years), with small (mean diameter 16.8 mm) HCC poorly visible at US underwent percutaneous microwave ablation under US/CBCT fusion guidance. During general anesthesia with apnea control, a contrast- enhanced CBCT was acquired with an active tracker. Subsequently, real time US images were fused with CBCT images, and treatment performed under fusion imaging guidance. Feasibility of fusion imaging and percutaneous ablation were assessed, correct targeting (distance from center of tumor and center of ablation area <5 mm) and one-month primary technical efficacy were evaluated. Major and minor complications as well as overall procedural time were recorded. Results: US/CBCT fusion was feasible in all cases, allowing for completion of the treatment as previously planned (technical success 100%). Correct targeting was achieved in 4/6 cases (66%), while in two cases, center of tumor and center of ablated area were respectively 7 and 8 mm distant. At 1 month CT scan, all tumors were completely ablated (primary technical efficacy 100%). No major or minor complications occurred. Mean overall procedure time was 127 min. Conclusions: US/CBCT fusion is a feasible technique for liver ablation, and might represent a useful tool to increase the correct targeting of poorly US-visible HCC nodules in the angio suite
The early and late-time spectral and temporal evolution of GRB 050716
We report on a comprehensive set of observations of Gamma Ray Burst 050716,
detected by the Swift satellite and subsequently followed-up rapidly in X-ray,
optical and near infra-red wavebands. The prompt emission is typical of
long-duration bursts, with two peaks in a time interval of T90 = 68 seconds (15
- 350 keV). The prompt emission continues at lower flux levels in the X-ray
band, where several smaller flares can be seen, on top of a decaying light
curve that exhibits an apparent break around 220 seconds post trigger. This
temporal break is roughly coincident with a spectral break. The latter can be
related to the extrapolated evolution of the break energy in the prompt
gamma-ray emission, and is possibly the manifestation of the peak flux break
frequency of the internal shock passing through the observing band. A possible
3 sigma change in the X-ray absorption column is also seen during this time.
The late-time afterglow behaviour is relatively standard, with an electron
distribution power-law index of p = 2 there is no noticable temporal break out
to at least 10 days. The broad-band optical/nIR to X-ray spectrum indicates a
redshift of z ~> 2 for this burst, with a host-galaxy extinction value of
E(B-V) ~ 0.7 that prefers an SMC-like extinction curve.Comment: Accepted to MNRAS. 8 pages, 5 figure
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