Theories of Technological Progress and the British Textile Industry from Kay to Cartwright

Editada en la Fundación Empresa PúblicaLa industria textil británica continúa en el centro del debate sobre la revolución industrial. Las innovaciones técnicas en el período produjeron una aceleración extraordinaria del crecimiento del output y una considerable reducción de los precios de los tejidos. En este trabajo presentamos un estudio de la comunidad de los inventores responsables de la transformación tecnológica, lo que nos permite alcanzar una serie de conclusiones nuevas sobre el ritmo y dirección de la actividad innovadora durante la revolución industrialThe cotton textile industry remains central to all accounts of the first industrial revolution. Innovations in this period precipitated an extraordinary acceleration in the growth of output and a steep decline in the cost of producing all varieties of cloth. In this paper we outline an explanation through an analysis of the community of inventors responsible for the technological transformation, which enables us to offer some generalizations of the pace and pattern of the inventive activity in this period.Publicad

Infrared Spectral Energy Distribution Model for Extremely Young Galaxies

The small grain sizes produced by Type II supernova (SN II) models in young, metal-poor galaxies make the appearance of their infrared (IR) spectral energy distribution (SED) quite different from that of nearby, older galaxies. To study this effect, we have developed a model for the evolution of dust content and the IR SED of low-metallicity, extremely young galaxies based on Hirashita et al. (2002). We find that, even in the intense ultraviolet (UV) radiation field of very young galaxies, small silicate grains are subject to stochastic heating resulting in a broad temperature distribution and substantial MIR continuum emission. Larger carbonaceous grains are in thermal equilibrium at T \simeq 50 - 100K, and they also contribute to the MIR. We present the evolution of SEDs and IR extinction of very young, low-metallicity galaxies. The IR extinction curve is also shown. In the first few Myrs, the emission peaks at \lambda \sim 30-50um at later times dust self-absorption decreases the apparent grain temperatures, shifting the bulk of the emission into the submillimetre band. We successfully apply the model to the IR SED of a low metallicity (1/41 Z_\odot) dwarf galaxy SBS0335-052. We find the SED, optical properties and extinction of the star forming region to be consistent with a very young and compact starburst. We also predict the SED of another extremely low-metallicity galaxy, I Zw 18, for future observational tests. Some prospects for future observations are discussed.Comment: MNRAS in press, pages, 6 figures, using mn2e.cls. Abstract abridge

Control of posture with FES systems

One of the major obstacles in restoration of functional FES supported standing in paraplegia is the lack of knowledge of a suitable control strategy. The main issue is how to integrate the purposeful actions of the non-paralysed upper body when interacting with the environment while standing, and the actions of the artificial FES control system supporting the paralyzed lower extremities. In this paper we provide a review of our approach to solving this question, which focuses on three inter-related areas: investigations of the basic mechanisms of functional postural responses in neurologically intact subjects; re-training of the residual sensory-motor activities of the upper body in paralyzed individuals; and development of closed-loop FES control systems for support of the paralyzed joints

The HI content of extremely metal-deficient blue compact dwarf galaxies

We have obtained new HI observations with the 100m Green Bank Telescope (GBT) for a sample of 29 extremely metal-deficient star-forming Blue Compact Dwarf (BCD) galaxies, selected from the Sloan Digital Sky Survey spectral data base to be extremely metal-deficient (12+logO/H<7.6). Neutral hydrogen was detected in 28 galaxies, a 97% detection rate. Combining the HI data with SDSS optical spectra for the BCD sample and adding complementary galaxy samples from the literature to extend the metallicity and mass ranges, we have studied how the HI content of a galaxy varies with various global galaxian properties. There is a clear trend of increasing gas mass fraction with decreasing metallicity, mass and luminosity. We obtain the relation M(HI)/L(g)~L(g)^{-0.3}, in agreement with previous studies based on samples with a smaller luminosity range. The median gas mass fraction f(gas) for the GBT sample is equal to 0.94 while the mean gas mass fraction is 0.90+/-0.15, with a lower limit of ~0.65. The HI depletion time is independent of metallicity, with a large scatter around the median value of 3.4 Gyr. The ratio of the baryonic mass to the dynamical mass of the metal-deficient BCDs varies from 0.05 to 0.80, with a median value of ~0.2. About 65% of the BCDs in our sample have an effective yield larger than the true yield, implying that the neutral gas envelope in BCDs is more metal-deficient by a factor of 1.5-20, as compared to the ionized gas.Comment: 21 pages, 13 figures, accepted for publication in MNRA

Glimmers: Resolving the Privacy/Trust Quagmire

Many successful services rely on trustworthy contributions from users. To establish that trust, such services often require access to privacy-sensitive information from users, thus creating a conflict between privacy and trust. Although it is likely impractical to expect both absolute privacy and trustworthiness at the same time, we argue that the current state of things, where individual privacy is usually sacrificed at the altar of trustworthy services, can be improved with a pragmatic $Glimmer$ $of$ $Trust$, which allows services to validate user contributions in a trustworthy way without forfeiting user privacy. We describe how trustworthy hardware such as Intel's SGX can be used client-side -- in contrast to much recent work exploring SGX in cloud services -- to realize the Glimmer architecture, and demonstrate how this realization is able to resolve the tension between privacy and trust in a variety of cases

How does star formation proceed in the circumnuclear starburst ring of NGC 6951?

Gas inflowing along stellar bars is often stalled at the location of circumnuclear rings, that form an effective reservoir for massive star formation and thus shape the central regions of galaxies. However, how exactly star formation is proceeding within these circumnuclear starburst rings is subject of debate. Two main scenarios for this process have been put forward: In the first the onset of star formation is regulated by the total amount of gas present in the ring with star forming starting once a mass threshold has reached in a `random' position within the ring like `popcorn'. In the second star formation preferentially takes place near the locations where the gas enters the ring. This scenario has been dubbed `pearls-on-a-string'. Here we combine new optical IFU data covering the full stellar bar with existing multi-wavelength data to study in detail the 580 pc radius circumnuclear starburst ring in the nearby spiral galaxy NGC 6951. Using HST archival data together with Sauron and Oasis IFU data, we derive the ages and stellar masses of star clusters as well as the total stellar content of the central region. Adding information on the molecular gas distribution, stellar and gaseous dynamics and extinction, we find that the circumnuclear ring in NGC 6951 is ~1-1.5 Gyr old and has been forming stars for most of that time. We see evidence for preferred sites of star formation within the ring, consistent with the `pearls-on-a-string' scenario, when focusing on the youngest stellar populations. Due to the ring's longevity this signature is washed out when older stellar populations are included in the analysis.Comment: accepted for publication in A&A, 15 page

Measuring categorisation in pre-school children: new toolkit, new insights

Introduction: whilst recent years have witnessed considerable research into infant categorisation, its development during the pre-school period has garnered far less interest and innovation. Objective: this paper documents the development of a valid and reliable new toolkit for measuring categorisation in children, designed to allow fine-grained differentiation through four short tasks. Methods: the paper outlines how a pilot study with 55 children reduced confounding variables, ruled out several explanations for performance variations and enabled procedural refinements. It then documents a study conducted with 190 children aged 30-60 months. Results: this more sophisticated testing mechanism challenges previously accepted developmental norms and suggests both sex and socio-economic status (and their interaction) influence categorisational abilities in pre-schoolers. Conclusion: the results indicate that preschool children’s ability to categorise varies markedly, with implications for their capacity to access formal education

Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium

Long-duration gamma-ray bursts (GRBs) are indisputably related to star formation, and their vast luminosity in gamma rays pin-points regions of star formation independent of galaxy mass. As such, GRBs provide a unique tool for studying star forming galaxies out to high-z independent of luminosity. Most of our understanding of the properties of GRB hosts (GRBHs) comes from optical and near-infrared (NIR) follow-up observations, and we therefore have relatively little knowledge of the fraction of dust-enshrouded star formation that resides within GRBHs. Currently ~20% of GRBs show evidence of significant amounts of dust along the line of sight to the afterglow through the host galaxy, and these GRBs tend to reside within redder and more massive galaxies than GRBs with optically bright afterglows. In this paper we present Herschel observations of five GRBHs with evidence of being dust-rich, targeted to understand the dust attenuation properties within GRBs better. Despite the sensitivity of our Herschel observations, only one galaxy in our sample was detected (GRBH 070306), for which we measure a total star formation rate (SFR) of ~100Mstar/yr, and which had a relatively high stellar mass (log[Mstar]=10.34+0.09/-0.04). Nevertheless, when considering a larger sample of GRBHs observed with Herschel, it is clear that stellar mass is not the only factor contributing to a Herschel detection, and significant dust extinction along the GRB sightline (A_{V,GRB}>1.5~mag) appears to be a considerably better tracer of GRBHs with high dust mass. This suggests that the extinguishing dust along the GRB line of sight lies predominantly within the host galaxy ISM, and thus those GRBs with A_{V,GRB}>1~mag but with no host galaxy Herschel detections are likely to have been predominantly extinguished by dust within an intervening dense cloud.Comment: 14 pages, 7 figures. Accepted for publication in A&