1,376 research outputs found
Jobfinding and wages when longrun unemployment is really long : the case of Spain
This paper uses the "Encuesta de Condiciones de Vida Y Trabajoll (ECVT)··
a survey of the labor force activity of over 61,000 persons in Spain in 1985
when unemployment exceeded 20%--to examine the effect of unemployrnent insurance (UI) and family status on longrun joblessness. It finds that (1)duratÃan of joblessness 1s 50me 30% longer for those eligible for UI benefits than for those ineligible for UI; (2) the longterm unemployed are
disproportionately secondary workers for whom the family serves as a form of
welfare; (3) hazard rates linking the chances of jobfinding to duration of
unemployment in the 1981-85 period of massive joblessness did not decline
with duration; (4) the length of unemployment spells reduces wages moderately
but has huge effect on the probability that re-employed workers take
secondary sector jobs; (5) the UI eligible earn more and are more likely to
gain regular full-time jobs than those ineligible for UI, congruent with the
additional months of Job search associated with UI.
The estimated effects of duratÃan on the hazard and on earnings are
consistent with the implications of labor supply and search analysis but not
with the view that long unemployment spells create a class of unemployables.
Our results imply a sizeable reduction in longterm unemployment with economic
recovery
Mixed unions reveal progress in integration but also enduring societal social cleavages, which revolve around race in the US and religion in Europe
Recent months have seen debates over immigration and the integration of immigrants into North American and Western European societies come to the fore in public discourse. In new research, Richard Alba and Nancy Foner assess the state of immigrant integration by analysing unions between those with non-Western immigrant origins and those from native majorities in North America and Western Europe. They find that, while the frequency of mixed unions varies among countries, the greater variation occurs among groups, reflecting pronounced social cleavages in different countries: racial divisions, especially between blacks and whites, in the United States and the separation between Muslims and long-established secular/Christian natives in Western Europe. Other factors, including the settler society experience in North America and cultural traditions among Muslim groups, also play a role
Mesoscopic structure of pectin in solution
Mesoscopic structure of pectin with different molecular characteristics was investigated by means of small angle X-ray scattering (SAXS), electrokinetic measurements and data modelling. The influence of a broad range of pH (2-7) on chain conformation in the dilute and semi-diluted regime was investigated. Scattering data and concomitant analysis revealed two length scales at all environmental conditions studied. pH showed greater influence at acidic values (pH 2.0) enhancing the globular component of the structure due to association of galacturonic acid residues. Double logarithmic scattering intensity plots revealed fractal dimensions of 1.9 ±0.2 in the low-q regime and 1.5 ±0.2 in the high q-region, irrespectively of the specific environment. Increase in branching of RG-I regions of the polysaccharide chains enhanced the compact conformation irrespectively of the pH or concentration. The present work shows that radical changes in pectin conformation can be induced only under strongly acidic conditions a finding that has important consequences in tailoring the technological performance of these biopolymer
Low-power photothermal self-oscillation of bimetallic nanowires
We investigate the nonlinear mechanics of a bimetallic, optically absorbing
SiN-Nb nanowire in the presence of incident laser light and a reflecting Si
mirror. Situated in a standing wave of optical intensity and subject to
photothermal forces, the nanowire undergoes self-induced oscillations at low
incident light thresholds of due to engineered strong
temperature-position (-) coupling. Along with inducing self-oscillation,
laser light causes large changes to the mechanical resonant frequency
and equilibrium position that cannot be neglected. We present
experimental results and a theoretical model for the motion under laser
illumination. In the model, we solve the governing nonlinear differential
equations by perturbative means to show that self-oscillation amplitude is set
by the competing effects of direct - coupling and parametric
excitation due to - coupling. We then study the linearized
equations of motion to show that the optimal thermal time constant for
photothermal feedback is rather than the widely reported
. Lastly, we demonstrate photothermal quality factor ()
enhancement of driven motion as a means to counteract air damping.
Understanding photothermal effects on micromechanical devices, as well as
nonlinear aspects of optics-based motion detection, can enable new device
applications as oscillators or other electronic elements with smaller device
footprints and less stringent ambient vacuum requirements.Comment: New references adde
Degradation mechanisms in martensitic stainless steels: wear, corrosion and tribocorrosion appraisal
[EN] A deep understanding of degradation mechanisms of metals is crucial for developing new materials with high performance. Within the different families of stainless steels, martensitic stainless steels are widely used in a great variety of industrial applications where mechanical properties, such as strength, wear resistance and fatigue behavior, need to be high. In many of those applications, such as bearings or gears, martensitic stainless steels may be subject to tribological conditions leading to wear. Furthermore, when a contact operates in a corrosive environment its deterioration can be significantly affected by surface chemical phenomena, leading to a tribocorrosion degradation mechanism. Indeed, martensitic stainless steels degrade through a great variety of wear and corrosion mechanisms. This paper aims to review the published data from 2005 to present related to wear, corrosion and tribocorrosion of martensitic stainless steels. Individual studies of tribological and corrosion behavior of martensitic stainless steels have been widely published since 2005. From the wear point of view, ploughing or abrasive wear in dry contacts involving martensitic stainless steel has been reported, while pitting corrosion is the most common mechanism for those steels. However, only nine papers were found since 2005 related to tribocorrosion of martensitic stainless steels, although most authors concluded that this joint action is the most important material degradation in martensitic stainless steels.Dalmau-Borrás, A.; Richard, C.; Igual Muñoz, AN. (2018). Degradation mechanisms in martensitic stainless steels: wear, corrosion and tribocorrosion appraisal. Tribology International. 121:167-179. https://doi.org/10.1016/j.triboint.2018.01.036S16717912
Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
We discuss new Keck/MOSFIRE spectroscopic observations of four luminous
galaxies at z~7-9 selected to have intense optical line emission by
Roberts-Borsani et al. (2016). Previous follow-up has revealed Lyman-alpha in
two of the four galaxies. Our new MOSFIRE observations confirm that Lyman-alpha
is present in the entire sample. We detect Lyman-alpha emission in COS-zs7-1,
confirming its redshift as z=7.154, and we detect Lyman-alpha in EGS-zs8-2 at
z=7.477, verifying a tentative detection presented in an earlier study. The
ubiquity of Lyman-alpha in this sample is puzzling given that the IGM is likely
significantly neutral over 7<z<9. To investigate this result in more detail, we
have initiated a campaign to target UV metal emission in the four Lyman-alpha
emitters as a probe of both the radiation field and the velocity offset of
Lyman-alpha. Here we present the detection of intense CIII] emission in
EGS-zs8-1, a galaxy from this sample previously shown to have Lyman-alpha at
z=7.73. Photoionization models indicate that an intense radiation field and low
metallicity are required to reproduce the intense CIII] and optical line
emission. We argue that this extreme radiation field is likely to affect the
local environment, increasing the transmission of Lyman-alpha through the
galaxy. Moreover, the centroid of CIII] indicates that Lyman-alpha is
redshifted from the systemic value by 340 km/s. This velocity offset is larger
than that seen in less luminous systems, providing an additional explanation
for the transmission of Lyman-alpha emission through the IGM. Since the
transmission is further enhanced by the likelihood that such systems are also
situated in the densest regions with the largest ionized bubbles, the
visibility of Lyman-alpha at z>7 is expected to be strongly
luminosity-dependent, with the most effective transmission occurring in systems
with intense star formation.Comment: Submitted to MNRAS, 13 pages, 8 figure
A Systematic Review of Strong Gravitational Lens Modeling Software
Despite expanding research activity in gravitational lens modeling, there is
no particular software which is considered a standard. Much of the
gravitational lens modeling software is written by individual investigators for
their own use. Some gravitational lens modeling software is freely available
for download but is widely variable with regard to ease of use and quality of
documentation. This review of 13 software packages was undertaken to provide a
single source of information. Gravitational lens models are classified as
parametric models or non-parametric models, and can be further divided into
research and educational software. Software used in research includes the
GRAVLENS package (with both gravlens and lensmodel), Lenstool, LensPerfect,
glafic, PixeLens, SimpLens, Lensview, and GRALE. In this review, GravLensHD,
G-Lens, Gravitational Lensing, lens and MOWGLI are categorized as educational
programs that are useful for demonstrating various aspects of lensing. Each of
the 13 software packages is reviewed with regard to software features
(installation, documentation, files provided, etc.) and lensing features (type
of model, input data, output data, etc.) as well as a brief review of studies
where they have been used. Recent studies have demonstrated the utility of
strong gravitational lensing data for mass mapping, and suggest increased use
of these techniques in the future. Coupled with the advent of greatly improved
imaging, new approaches to modeling of strong gravitational lens systems are
needed. This is the first systematic review of strong gravitational lens
modeling software, providing investigators with a starting point for future
software development to further advance gravitational lens modeling research
Characterization of Heat Melt Compactor (HMC) Product Water
The Heat Melt Compactor (HMC) is designed to sterilize and process wastes produced during space missions. Benefits of the HMC include reduction of biohazards to the crew, reduction in volume of wastes that would otherwise require storage, production of radiation shielding tiles, and recovery of water and other resources. Water reuse is critical onboard spacecrafts; it reduces the need for resupply missions and saves valuable storage space. The main sources of water in HMC batches are food, beverages, shampoo, disinfecting wipes, toothpaste, and diapers. Water reclaimed by the HMC was analyzed for concentrations of Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO2-, Br-, NO3-, PO43-, SO42-, total organic carbon (TOC), total inorganic carbon (TIC), % total solids, and pH. The data are discussed in relation to the current water input characteristics established for the International Space Station Water Processor Assembly system. Batches with higher than average amounts of food produced HMC product water with higher sulfate content, and batches with higher proportions of disinfectant wipes and food yielded HMC product water with higher ammonium concentration. We also compared theoretical chemical composition of HMC product water based on food labels and literature values to experimental results
Exploring citizen participation in smart city development in Mexico city: an institutional logics approach
We explore smart city development, with a focus on the modalities of citizen participation, using an institutional logics approach. Taking Mexico City as our case study, we describe the presence and dynamics of several logics influencing smart city development. At an organizational level we identify the bureaucratic and technocratic logics underpinning the practices of the governmental agency leading smart city development. Characterized by centralization and the pursuit of efficiency, and framed by a discourse of austerity and financial control, these logics promote a modality of citizen participation that is limited and unidirectional in nature, with citizens positioned largely as users. At a supra-organizational level, we identify a logic of active citizen participation in urban governance that is formalized in city laws. However, this logic is itself entangled in a logic of clientelism and patronage, manifested through networks of power. These logics work synergistically to limit broader, inclusive citizen participation in, and realization of benefits from, smart city agendas. We conclude that a richer understanding of institutional logics enhances the analysis of the social construction of the smart city in particular, situated contexts.Economic and Social Research Council | Ref. ES/S006710/
Exploring citizen participation in smart city development in Mexico City: an institutional logics approach
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