Probing the Low Surface Brightness Dwarf Galaxy Population of the Virgo Cluster

We have used public data from the Next Generation Virgo Survey (NGVS) to investigate the dwarf galaxy population of the Virgo cluster beyond what has previously been discovered. We initially mask and smooth the data, and then use the object detection algorithm Sextractor to make our initial dwarf galaxy selection. All candidates are then visually inspected to remove artefacts and duplicates. We derive Sextractor parameters to best select low surface brightness galaxies using g band central surface brightness values of 22.5 to 26.0 mag sq arc sec and exponential scale lengths of 3.0 - 10.0 arc sec to identify 443 cluster dwarf galaxies - 303 of which are new detections. These new detections have a surface density that decreases with radius from the cluster centre. We also apply our selection algorithm to 'background', non-cluster, fields and find zero detections. In combination, this leads us to believe that we have isolated a cluster dwarf galaxy population. The range of objects we are able to detect is limited because smaller scale sized galaxies are confused with the background, while larger galaxies are split into numerous smaller objects by the detection algorithm. Using data from previous surveys combined with our data, we find a faint end slope to the luminosity function of -1.35+/-0.03, which does not significantly differ to what has previously been found for the Virgo cluster, but is a little steeper than the slope for field galaxies. There is no evidence for a faint end slope steep enough to correspond with galaxy formation models, unless those models invoke either strong feedback processes or use warm dark matter.Comment: Accepted for publication in MNRA

UNICEF IWASH Project, Northern Region, Ghana : an adapted training manual for groundwater development

This report is an adapted training manual, with specific best practice recommendations for groundwater development practitioners working in the Northern Region, Ghana. It is designed to be used in conjunction with the existing comprehensive training manual ‘Developing Groundwater: a guide to rural water supply’ by MacDonald, Davies, Calow and Chilton (2005). The additional guidelines provided in this supplementary report are specific to the Northern Region of Ghana, and have been informed by a review of groundwater development in the region which BGS carried out on behalf of UNICEF in 2010-2011. The Northern Region is a difficult area in which to find and develop groundwater resources. For this reason, more resources – time and money – need to be focussed on careful borehole siting and development in order to maximise success. This includes detailed desk and field reconnaissance surveys; the effective use and interpretation of geophysical siting methods; collection of good quality data during drilling and test pumping; rigorous recording and management of data; and effective interpretation, sharing and use of hydrogeological information by all groundwater development practitioners. This report, and the associated manual ‘Developing Groundwater’, provide practical help for carrying out these activities effectively. The authors gratefully acknowledge those persons who contributed to the formation of these guidelines, who include: UNICEF Ghana – Othniel Habila, Kabuka Banda and David Ede Community Water and Sanitation Agency (CWSA), Ghana – John Aduakye Canadian International Development Agency (CIDA) – Hydrogeological Assessment Project (HAP) – James Racicot All participants at the UNICEF/BGS workshop and training programme held in Tamale, Northern Region, from 7 to 18 February 2011

Electron-electron interactions in antidot-based Aharonov-Bohm interferometers

We present a microscopic picture of quantum transport in quantum antidots in the quantum Hall regime taking electron interactions into account. We discuss the edge state structure, energy level evolution, charge quantization and linear-response conductance as the magnetic field or gate voltage is varied. Particular attention is given to the conductance oscillations due to Aharonov-Bohm interference and their unexpected periodicity. To explain the latter we propose the mechanisms of scattering by point defects and Coulomb blockade tunneling. They are supported by self-consistent calculations in the Hartree approximation, which indicate pinning and correlation of the single-particle states at the Fermi energy as well as charge oscillation when antidot-bound states depopulate. We have also found interesting phenomena of anti-resonance reflection of the Fano type.Comment: 12 pages, 8 figure

Cunning-folk in the medical market-place during the nineteenth century.

Copyright © Cambridge University Press 1999Over the last twenty years a considerable amount of valuable research has uncovered the activities of a variety of unorthodox medical practitioners in the eighteenth and nineteenth centuries. Quack doctors, spiritual healers, medical botanists, and bone-setters have all been subjected to detailed analysis. In contrast, the practitioners of folk-magical healing have been largely overlooked. This neglect of a significant sector of the nineteenth-century medical market-place is probably due to the nature of the relevant source material. Most of the information we have about cunning-folk derives from ethnographic sources and newspaper reports. The considerable body of folkloric material on cunning-folk has been particularly overlooked because of historians' general disregard for the anecdotal, and unsystematic way in which much of this information was gathered. However, when folkloric sources are examined in conjunction with the concrete data supplied in newspaper reports of the prosecution of cunning-folk, new light is cast on the popular experience of healing during the nineteenth century.3 The aim of the following discussion, therefore, is to introduce cunning-folk to the debate over medical provision in nineteenth-century society, and to examine their relationship with other groups of medical providers in terms of practice and public perceptionPeer reviewe

The Niger Delta and Human Rights in Nigeria

The Niger Delta Region in the enclave called Nigeria today has been terribly locked in an endless battle for its Human Rights which also includes the right to development and economic autonomy, with various predatory institutions which have across time, relentlessly sought to command its immense natural wealth and dictate to it the terms and manner of development it must follow. The world conference on Human Rights held in Vienna, Austria recognized the fact that development rights are arguably fundamental and inalienable rights. The recognition of the right to development and the meeting of basic economic and social needs as part of fundamental human rights by the conference marked a turning point in the United Nations recognition of only Civil rights as fundamental human rights.This paper takes a look at the Niger Delta , its problems of human rights to which development rights is a part and contends that the Niger Delta development rights must be promoted and defended at all cost on the basis of proper understanding of the institutionalization of a transparent and genuine democracy. KeyWords:*Niger Delta, *human rights, *development, *resource control, *Nigeria, *fundamental rights, *linternational la

Public ubiquitous computing systems:lessons from the e-campus display deployments

In this paper we reflect on our experiences of deploying ubiquitous computing systems in public spaces and present a series of lessons that we feel will be of benefit to researchers planning similar public deployments. We focus on experiences gained from building and deploying three experimental public display systems as part of the e-campus pro ject. However, we believe the lessons are likely to be generally applicable to many different types of public ubicomp deployment

Bir yabancı gözile İstanbul'un surları II

Taha Toros Arşivi, Dosya No: 122-Surlarİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033