Children's work in Spanish textiles during the 19th and 20th Centuries

This essay deals with the reasons explaining children s work in 19th century textile factories and their removal during the first part of the 20th century. The inadequacy of the structure of incomes and expenditures of the household and the very low economic incentives to educate children can explain why children were in the factories and not in the school. Moreover, the marginal economic contribution to the economy of the household of a child was the same as that of his mother. This normally implied that women and children were perfect substitutes. When the family had a child at working age this allowed to replace the paid work input of the mother. With the beginnings of the 20th century a set of changes leading to the increase of women s productivity and hourly real wages, switched the situation and involved the new incorporation of women into paid work and the investment in children s human capital.

Aggregate shocks or vertical tax interdependence? Evidende from gasoline and cigarettes

[cat] Besley i Rosen -1998- van ser els primers autors en estimar empíricament la rellevància de les externalitats impositives verticals. Aquests autors varen fer-ho per al cas dels impostos sobre la benzina i el tabac, en concret, per al cas dels EEUU. Ara bé, no varen tenir en compte les diferències en el nivell de vida entre Estats: àrees amb un nivell elevat paguen menys en termes reals que àrees amb un nivell de vida baix, doncs l'impost unitari sobre la benzina o sobre el tabac no difereix d'acord amb l'Estat on l'impost s'aplica. En conseqüència, proposem que la competència impositiva vertical sigui estimada deflactant totes les variables monetàries utilitzant l'anomenat "House Price Index (HPI)", el qual està disponible al nivell dels Estats. Això genera una variable impositiva federal expressada en termes reals i que presenta variació entre Estats. Aquesta estratègia empírica ens permet diferenciar entre la interdependència vertical entre els tipus impositius federals i els estatals de shocks agregats al llarg del temps, utilitzant dades per als EEUU durant el període 1975 a 2006 per a benzina i tabac. Trobem una nivell significatiu de competència impositiva horitzontal, la qual és més elevada en el cas del tabac, però en cap cas reacció impositiva vertical. Els resultats són robustos al període analitzat.

Aggregate shocks or vertical tax interdependence? Evidende from gasoline and cigarettes

[cat] Besley i Rosen -1998- van ser els primers autors en estimar empíricament la rellevància de les externalitats impositives verticals. Aquests autors varen fer-ho per al cas dels impostos sobre la benzina i el tabac, en concret, per al cas dels EEUU. Ara bé, no varen tenir en compte les diferències en el nivell de vida entre Estats: àrees amb un nivell elevat paguen menys en termes reals que àrees amb un nivell de vida baix, doncs l'impost unitari sobre la benzina o sobre el tabac no difereix d'acord amb l'Estat on l'impost s'aplica. En conseqüència, proposem que la competència impositiva vertical sigui estimada deflactant totes les variables monetàries utilitzant l'anomenat "House Price Index (HPI)", el qual està disponible al nivell dels Estats. Això genera una variable impositiva federal expressada en termes reals i que presenta variació entre Estats. Aquesta estratègia empírica ens permet diferenciar entre la interdependència vertical entre els tipus impositius federals i els estatals de shocks agregats al llarg del temps, utilitzant dades per als EEUU durant el període 1975 a 2006 per a benzina i tabac. Trobem una nivell significatiu de competència impositiva horitzontal, la qual és més elevada en el cas del tabac, però en cap cas reacció impositiva vertical. Els resultats són robustos al període analitzat.

Multipole modes and spin features in the Raman spectrum of nanoscopic quantum rings

We present a systematic study of ground state and spectroscopic properties of many-electron nanoscopic quantum rings. Addition energies at zero magnetic field (B) and electrochemical potentials as a function of B are given for a ring hosting up to 24 electrons. We find discontinuities in the excitation energies of multipole spin and charge density modes, and a coupling between the charge and spin density responses that allow to identify the formation of ferromagnetic ground states in narrow magnetic field regions. These effects can be observed in Raman experiments, and are related to the fractional Aharonov-Bohm oscillations of the energy and of the persistent current in the ring

Nonparabolicity and dielectric effects on addition energy spectra of spherical nanocrystals

An extension of the spin density functional theory simultaneously accounting for dielectric mismatch between neighboring materials and nonparabolicity corrections originating from interactions between conduction and valence bands is presented. This method is employed to calculate ground state and addition energy spectra of homogeneous and multishell spherical quantum dots. Our calculations reveal that corrections become especially relevant when they come into play simultaneously in strong regimes of spatial confinement.

Scaling and data collapse for the mean exit time of asset prices

We study theoretical and empirical aspects of the mean exit time (MET) of financial time series. The theoretical modeling is done within the framework of continuous time random walk. We empirically verify that the mean exit time follows a quadratic scaling law and it has associated a prefactor which is specific to the analyzed stock. We perform a series of statistical tests to determine which kind of correlation are responsible for this specificity. The main contribution is associated with the autocorrelation property of stock returns. We introduce and solve analytically both two-state and three-state Markov chain models. The analytical results obtained with the two-state Markov chain model allows us to obtain a data collapse of the 20 measured MET profiles in a single master curve.

Ground and excited states of KNiF3: An ab initio cluster-model approach

Finite cluster models and a variety of ab initio wave functions have been used to study the electronic structure of bulk KNiF3. Several electronic states, including the ground state and some charge-transfer excited states, have been considered. The study of the cluster-model wave functions has permitted an understanding of the nature of the chemical bond in the electronic ground state. This is found to be highly ionic and the different ionic and covalent contributions to the bonding have been identified and quantified. Finally, we have studied the charge-transfer excited states leading to the optical gap and have found that calculated and experimental values are in good agreement. The wave functions corresponding to these excited states have also been analyzed and show that although KNiF3 may be described as a ligand-to-metal charge-transfer insulator there is a strong configuration mixing with the metal-to-metal charge-transfer states.

Shear thinning and thixotropy of HMHEC and HEC water solutions

Steady state viscosity and thixotropy of hydrophobically modified hydroxyethyl cellulose HMHEC and nonassociative cellulose water solutions are studied. Although all the samples are shear thinning, only the HMHEC is thixotropic, since the migration of hydrophobes to micelles is controlled by diffusion. The Cross model fits steady state curves. The Mewis model, a phenomenological model that proposes that the rate of change of viscosity when the shear rate is suddenly changed is related to the difference between the steady state and current values of viscosity raised to an exponent, fits structure construction experiments when the exponent, n, is estimated to be around 2. The Newtonian assumption used by Mewis cannot be used here, however. This seems to be related to the fact that the thickening is due to bridged micelle formation, which is a slow process, and also to topological constraints and entanglements, which are rapid processes. The kinetic parameter was redefined to kn in order to make it independent of initial conditions. So, kn depends only on how the shear affects the structure. kn reaches a plateau at shear rates too low to produce structure destruction and decreases at higher shear rates.

How we experience immersive virtual environments: the concept of presence and its measurement

This paper reviews the concept of presence in immersive virtual environments, the sense of being there signalled by people acting and responding realistically to virtual situations and events. We argue that presence is a unique phenomenon that must be distinguished from the degree of engagement, involvement in the portrayed environment. We argue that there are three necessary conditions for presence: the (a) consistent low latency sensorimotor loop between sensory data and proprioception; (b) statistical plausibility: images must be statistically plausible in relation to the probability distribution of images over natural scenes. A constraint on this plausibility is the level of immersion;(c) behaviour-response correlations: Presence may be enhanced and maintained over time by appropriate correlations between the state and behaviour of participants and responses within the environment, correlations that show appropriate responses to the activity of the participants. We conclude with a discussion of methods for assessing whether presence occurs, and in particular recommend the approach of comparison with ground truth and give some examples of this.

Glassy magnetic phase driven by short range charge and magnetic ordering in nanocrystalline La1/3Sr2/3FeO3-δ: Magnetization, Mössbauer, and polarized neutron studies

The charge ordered La1/3Sr2/3FeO3−δ (LSFO) in bulk and nanocrystalline forms are investigated using ac and dc magnetization, M¨ossbauer, and polarized neutron studies. A complex scenario of short-range charge and magnetic ordering is realized from the polarized neutron studies in nanocrystalline specimen. This short-range ordering does not involve any change in spin state and modification in the charge disproportion between Fe3+ and Fe5+ compared to bulk counterpart as evident in the M¨ossbauer results. The refinement of magnetic diffraction peaks provides magnetic moments of Fe3+ and Fe5+ are about 3.15 μB and 1.57 μB for bulk, and 2.7 μB and 0.53 μB for nanocrystalline specimen, respectively. The destabilization of charge ordering leads to magnetic phase separation, giving rise to the robust exchange bias (EB) effect. Strikingly, EB field at 5 K attains a value as high as 4.4 kOe for average size ∼70 nm, which is zero for the bulk counterpart. A strong frequency dependence of ac susceptibility reveals cluster-glass-like transition around ∼65 K, below which EB appears. Overall results propose that finite-size effect directs the complex glassy magnetic behavior driven by unconventional short-range charge and magnetic ordering, and magnetic phase separation appears in nanocrystalline LSFO.

How we experience immersive virtual environments: the concept of presence and its measurement

This paper reviews the concept of presence in immersive virtual environments, the sense of being there signalled by people acting and responding realistically to virtual situations and events. We argue that presence is a unique phenomenon that must be distinguished from the degree of engagement, involvement in the portrayed environment. We argue that there are three necessary conditions for presence: the (a) consistent low latency sensorimotor loop between sensory data and proprioception; (b) statistical plausibility: images must be statistically plausible in relation to the probability distribution of images over natural scenes. A constraint on this plausibility is the level of immersion;(c) behaviour-response correlations: Presence may be enhanced and maintained over time by appropriate correlations between the state and behaviour of participants and responses within the environment, correlations that show appropriate responses to the activity of the participants. We conclude with a discussion of methods for assessing whether presence occurs, and in particular recommend the approach of comparison with ground truth and give some examples of this.

Study of D J meson decays to D +π-, D 0π+ and D ∗+π- final states in pp collisions

A study of D +π−, D 0π+ and D ∗+π− final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The D 1(2420)0 resonance is observed in the D ∗+π− final state and the D∗2(2460) resonance is observed in the D +π−, D 0π+ and D ∗+π− final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the D ∗+π−, D +π− and D 0π+ final states.

Molecular Physics of Elementary Processes relevant to Hypersonics: atom-molecule, molecule-molecule and atom-surface processes.

In the present chapter some prototype gas and gas-surface processes occurring within the hypersonic flow layer surrounding spacecrafts at planetary entry are discussed. The discussion is based on microscopic dynamical calculations of the detailed cross sections and rate coefficients performed using classical mechanics treatments for atoms, molecules and surfaces. Such treatment allows the evaluation of the efficiency of thermal processes (both at equilibrium and nonequilibrium distributions) based on state-to-state and state specific calculations properly averaged over the population of the initial states. The dependence of the efficiency of the considered processes on the initial partitioning of energy among the various degrees of freedom is discussed.

Nutritional and feeding ecology in the Cory"s shearwater (Calonectris diomedea).

In birds, parents adjust their feeding behaviour according to breeding duties, which ultimately may lead to seasonal adjustments in nutritional physiology and hematology over the breeding season. Although avian physiology has been widely investigated in captivity, few studies have integrated individual changes in feeding and physiological ecology throughout the breeding season in wild birds. To study relationships between feeding ecology and nutritional ecophysiology in Cory"s shearwater Calonectris diomedea, we weighed and took blood samples from 28 males and 19 females during the pre-laying, egg-laying, incubation, hatching and chick-rearing periods of the breeding season. In addition, we fitted 6 birds with geolocators to track their foraging movements throughout the reproductive period. Thus, we examined individual changes in (1) nutritional condition (biochemistry metabolites); (2) oxygen carrying capacity (hematology); and (3) feeding areas and foraging effort (stable isotopes and foraging movements). Geolocators revealed a latitudinal shift in main feeding areas towards more southern and more neritic waters throughout the breeding season, which is consistent with the steady increase in δ13C signatures in the blood. Geolocators also showed a decrease in foraging effort from egg-laying to hatching, reflecting the activity decrease associated with incubation duties. Plasma metabolites, body mass and oxygen carrying capacity were associated with temporal changes in nutritional state and foraging effort in relation to recovery after migration, egg formation, fasting shifts during incubation and chick provisioning. This study shows that combining physiological and ecological approaches can help us understand the influence of breeding duties on feeding ecology and nutritional physiology in wild birds.