Does lighting affect pedestrian flows? A pilot study in Lund, Market Harborough and Dublin

A study records pedestrian footfalls in Lund, Dublin and Market Harborough during the day and after dark, either side of the Autumn 2016 clock change, using the change of end of civil twilight time to measure the effect of different lighting levels at the same clock time on footfall rates. Examination of total footfalls on weekdays and at weekends found significant decreases in counts after the clock change, on 5/6 sites on weekdays and half the sites at weekends. Further analysis found that the percentage decrease in the counts in the test period (same time/day of the week, light one week, dark the next) was more than in the control period (same time/day of the week, light both weeks), in 79% of counting sessions. The findings demonstrate higher reduction in footfalls on weekdays in mixed use areas, such as the sites selected in Dublin, and on Sundays in non-central locations

Radio Pulse Properties of the Millisecond Pulsar PSR J0437-4715. I. Observations at 20cm

We present a total of 48 minutes of observations of the nearby, bright millisecond pulsar PSR J0437-4715 taken at the Parkes radio observatory in Australia. The data were obtained at a central radio frequency of 1380 MHz using a high-speed tape recorder that permitted coherent Nyquist sampling of 50 MHz of bandwidth in each of two polarizations. Using the high time resolution available from this voltage recording technique, we have studied a variety of single-pulse properties, most for the first time in a millisecond pulsar. We find no evidence for "diffractive" quantization effects in the individual pulse arrival times or amplitudes as have been reported for this pulsar at lower radio frequency using coarser time resolution (Ables et al. 1997). Overall, we find that the single pulse properties of PSR J0437-4715 are similar to those of the common slow-rotating pulsars, even though this pulsar's magnetosphere and surface magnetic field are several orders of magnitude smaller than those of the general population. The pulsar radio emission mechanism must therefore be insensitive to these fundamental neutron star properties.Comment: 24 Postscript pages, 11 eps figures. Accepted for publication in the Astrophysical Journal. Abbreviated abstract follow

Optical fibre digital pulse-position-modulation assuming a Gaussian received pulse shape

The abundance in bandwidth available in the best monomode fibres may be exchanged for improved receiver sensitivity by employing digital PPM. The paper presents a performance and optimisation analysis for a digital PPM coding scheme operating over a fibre channel employing a PIN-BJT receiver and assuming a Gaussian received pulse shape. The authors present original results for a 50 Mbit/s, 1.3 μm wavelength digital PPM system and conclude that, provided the fibre bandwidth is several times that of the data rate, digital PPM can outperform commercially available PIN-BJT binary PCM system

Multi-Epoch Observations of Survey Sources

Five objects mapped as part of a VLBI survey have been re-observed at 5 GHz, and four of them have also been observed at 10 GHz. Three of the objects show no substantial structural variations: an upper limit of 2c can be placed on the apparent relative velocities of the components. One object (0711+356) shows structural variations which are mostly simply described in terms of a superluminal contraction. The remaining object (3C371, 1807+698) shows substantial structural variations which suggest that it probably is a superluminal source. The source 0710+439 is especially interesting as it consists of a central flat-spectrum core component straddled by two compact steep-spectrum components

Implantacion de un costeo por actividades

298 p.Los esfuerzos vertidos en el presente estudio apuntan principalmente a la implantación y propuesta de un modelo metodológico del costeo basado en la actividad (ABC), a la Facultad de Ciencias Empresariales de la Universidad de Talca. La metodología empleada se orienta a la generación de "Impulsores de Costo" durante dos instancias del proceso productivo (Recurso - Actividad y Actividad - Producto) par media de "Jerarquización de Actividades", "Categorización de Recurso", etc. Las fuentes de indagación de los costos de los Recursos Humanos y no Humanos descansan en bases de dates oficiales de la organización, mientras que los referentes a las Actividades consideradas, se obtuvieran con apoyo de una encuesta efectuada al personal docente de la Facultad. En cuanto a los resultados obtenidos, estos aunque cuantitativamente esperados, lograron aportar al especto administrativo y financiero una mayor información. de esta manera, desde un punto de vista general, se logro el financiamiento del modelo ABC disef5ado• Dentro de las conclusiones logradas, creemos que la más importante es señalar que la adopción de un modelo ABC por una organización, debería pasar por procesos administrativos que logren internalizar esta idea a un diseño de control de gestic5n adecuado que provea al modelo de la información que necesita

Information and Communication Flows through Community Multimedia Centers: Perspectives from Mozambican Communities.

Community multimedia centers (CMCs) are considered by initiating agencies as instruments able to inform, entertain and educate the population, as well as to offer them a voice into knowledge society and to public initiatives. This article presents a quali-quantitative content analysis of 230 interviews held with staff members, users of the venues, people of the community who listen to their radio component but do not use their telecenters, and community members not using CMCs. The sample includes 10 CMCs around Mozambique. The purpose of the study is to investigate the perception of local communities of inbound, outbound, and shared information and communication flows connected to CMCs. Results highlight how CMCs are perceived as inbound information enablers, mostly by means of their community radio component, and as means to share information and communication within the communities' boundaries. Yet, CMCs still do not appear to be widely recognized as participation means to a reality that transcends the communities' physical borders

On the Nature of Andromeda IV

Lying at a projected distance of 40' or 9 kpc from the centre of M31, Andromeda IV is an enigmatic object first discovered during van den Bergh's search for dwarf spheroidal companions to M31. Being bluer, more compact and higher surface brightness than other known dwarf spheroidals, it has been suggested that And IV is either a relatively old `star cloud' in the outer disk of M31 or a background dwarf galaxy. We present deep HST WFPC2 observations of And IV and the surrounding field which, along with ground-based long-slit spectroscopy and Halpha imagery, are used to decipher the true nature of this puzzling object. We find compelling evidence that And IV is a background galaxy seen through the disk of M31. The moderate surface brightness (SB(V)~24), very blue colour (V-I<~0.6), low current star formation rate (~0.001 solar mass/yr) and low metallicity (~10% solar) reported here are consistent with And IV being a small dwarf irregular galaxy, perhaps similar to Local Group dwarfs such as IC 1613 and Sextans A. Although the distance to And IV is not tightly constrained with the current dataset, various arguments suggest it lies in the range 5<~D<~8 Mpc, placing it well outside the confines of the Local Group. It may be associated with a loose group of galaxies, containing major members UGC 64, IC 1727 and NGC 784. We report an updated position and radial velocity for And IV.Comment: 26 pages, LaTex with 9 figures (including 6 jpg plates). Accepted for publication in A

Evidence for two classes of parsec-scale radio double source in active galactic nuclei

There is a group of powerful compact radio sources which have two almost equal flux density components on parsec scales. On the basis of multifrequency, multiepoch Very Long Base Interferometry (VLBI) observations, we conclude that there are two physically distinct classes among such sources. In one class the two components are probably 'minilobes' where oppositely directed jets terminate. Because of their intrinsic symmetry we believe the new name 'compact symmetric objects' best describes this class of object. We present detailed observations of the source 0108+388, showing that this source has properties consistent with this class, including a very small limit on relative internal motions of is ≤ 0.18/h^(-1) (c) (using H_0 = 100 h km s^(-1) Mp c^(-1) and q_0 = 0.5). We also detect a weak feature between the two main components which may be associated with the central engine in this source. We believe there exists another class of double source composed of core-jet sources in which a component in the jet is as bright as the component associated with the central engine. These sources are distinct from those of the first class in showing systematic differences in the properties of the two components. All these sources have small relative motions between the two main components (e.g., in 2021+614 we detect a motion of 0.13 h^(-1)(c) and in 0711+356 an upper limit of 0.4 h^(-1)(c)). The combination of large relative brightness for the secondary and the low velocities might be explained if the secondary is due to a bright standing shock in the jet. Alternatively, the bright secondary component might be due to a relativistic flow close to the line of sight at a point along a curving parsec-scale channel (as has been proposed for 4C 39.25)

Landing and catalytic characterization of individual nanoparticles on electrode surfaces

We demonstrate a novel and versatile pipet-based approach to study the landing of individual nanoparticles (NPs) on various electrode materials without any need for encapsulation or fabrication of complex substrate electrode structures, providing great flexibility with respect to electrode materials. Because of the small electrode area defined by the pipet dimensions, the background current is low, allowing for the detection of minute current signals with good time resolution. This approach was used to characterize the potential-dependent activity of Au NPs and to measure the catalytic activity of a single NP on a TEM grid, combining electrochemical and physical characterization at the single NP level for the first time. Such measurements open up the possibility of studying the relation between the size, structure and activity of catalyst particles unambiguously