Diversity and burglary: Do community differences matter?

Diversity within a population has been linked to levels of both social cohesion and crime. Neighborhood crimes are the result of a complex set of factors, one of which is weak community cohesion. This article seeks to explore the impacts of diversity on burglary crime in a range of neighborhoods, using Leeds, UK as a case study. We propose a new approach to quantifying the correlates of burglary in urban areas through the use of diversity metrics. This approach is useful in unveiling the relationship between burglary and diversity in urban communities. Specifically, we employ stepwise multiple regression models to quantify the relationships between a number of neighborhood diversity variables and burglary crime rates. The results of the analyses show that the variables that represent diversity were more significant when regressed against burglary crime rates than standard socio‐demographic data traditionally used in crime studies, which do not generally use diversity variables. The findings of this study highlight the importance of neighborhood cohesion in the crime system, and the key place for diversity statistics in quantifying the relationships between neighborhood diversities and burglary. The study highlights the importance of policy planning aimed at encouraging community building in promoting neighborhood safety.     

Terrestrial, planetary and interplanetary magnetic fields

A discussion meeting at Burlington House on 10 March 2000 featured eight speakers and an audience of about 50. Andy Smith reports.     

欧洲牡蛎两个种群的遗传变异

用淀粉凝胶电泳检测和比较了来自爱尔兰自然群体和威尔土养殖群体的欧洲牡蛎Ostreaedulis11个基因位点的遗传变异。结果表明,两群体的平均杂合度观察值分别为0．081和0．144,多态位点比例（P0.99）分别为57．9％和42．1％,平均等位基因数分别为1．7和1．6,与已报道的欧洲牡额其他群体很接近,但与其他种类的牡蛎相比却很低。两群体之间相比,威尔土养殖群体的平均杂合度观察值明显大于爱尔兰自然群体的。这说明人为作用可以引起欧洲牡蛎群体的遗传差异。     

Late Quaternary speleothem pollen in the British Isles

As with many terrestrial areas, the British Quaternary sequence is characterised by incomplete, fragmentary records, whose correlation is based on stratigraphic or biostratigraphic techniques due to the lack of radiometric ages beyond the ～40 kyr limit of ¹⁴C dating. Speleothems (secondary cave calcite deposits) offer a significant advantage over many sources of palaeoenvironmental information; they can be dated to a high precision and accuracy by uranium‐thorium (²³⁸U‐²³⁰Th) thermal ionisation and inductively coupled plasma (ICP) mass spectrometry in the time period back to 500 kyr. They may also contain sufficient well‐preserved pollen representative of contemporary vegetation above the cave to allow palaeoenvironmental reconstruction. This study adopts the novel approach of combining pollen and thermal ionisation mass spectrometric (TIMS) U‐Th dating of British speleothems to produce well‐constrained palaeoenvironmental records. We report for the first time precisely dated records of pollen assemblages from speleothems suggesting the presence of thermophilous arboreal species in phases previously considered to have been consistently cool or cold and devoid of trees. Copyright © 2007 John Wiley & Sons, Ltd.     

Geochemical signature of historical mining: Fowey Estuary, Cornwall, UK

Geochemical analyses of intertidal sediments from the northern part of the Fowey Estuary, Cornwall, UK, reveal a clear pulse in Sn concentration in sediments which predate 1880. Sn concentrations at the base of the cores increase rapidly to peak values of 1200 ppm and then decrease to values of 200 ppm at the present-day sediment surface. The mineralogy of the sediments is consistent with an origin from the release of mine waste from tin streaming and smelt products into the estuary. Further to the south, the down-core geochemistry of the estuary sediments is uniform with values of typically 400 ppm. This is interpreted as due to the natural reworking of the recognised pulse in particulate mine waste seen to the north.     

Placement of sensors/actuators on civil structures using genetic algorithms

The optimal design and placement of controllers at discrete locations is an important problem that will have impact on the control of civil engineering structures. Though algorithms exist for the placement of sensor/actuator systems on continuous structures, the placement of controllers on discrete civil structures is a very difficult problem. Because of the nature of civil structures, it is not possible to place sensors and actuators at any location in the structure. This usually creates a non‐linear constrained mixed integer problem that can be very difficult to solve. Using genetic algorithms in conjunction with gradient‐based optimization techniques will allow for the simultaneous placement and design of an effective structural control system. The introduction of algorithms based on genetic search procedures should increase the rate of convergence and thus reduce the computational time for solving the difficult control problem. The newly proposed method of simultaneously placing sensors/actuators will be compared to a commonly used method of sensors/actuators placement where sensors/actuators are placed sequentially. The savings in terms of energy requirements and cost will be discussed. Copyright © 2001 John Wiley & Sons, Ltd.     

A new approach to detecting vegetation and land-use change using high-resolution lipid biomarker records in stalagmites

A hundred-year stalagmite lipid biomarker record from Mechara, southeastern Ethiopia, is presented. The record has been recovered at a 10-yr temporal resolution, marking the first time this has been achieved in stalagmite biomarker work and providing the first opportunity to investigate the relationship between stalagmite lipid records and hydrological transport lags, a vital issue in interpreting palaeoenvironmental signals. Preserved plant-derived n-alkanes and n-alkanols show clear changes in composition over time, relating to known land-use changes in the area, particularly the expansion of agriculture in the early twentieth century. The level of environmental detail provided by this technique, combined with the long-term chronological framework offered by stalagmites, holds significant promise for the investigation of early human environments and their associated climatic and anthropogenic controls.     

PREDICTING THE DEPTH OF EROSION IN RESERVOIRS FOLLOWING DAM REMOVAL USING BANK STABILITY ANALYSIS

1 INTRODUCTION 1. 1 Dam Removal The aging of the more than 75,000 dams in the U.S., coupled with the increasing awareness of their environmental costs, has made dam decommissioning and removal a topic of current interest to the scientific community, management agencies, and the general public. It is estimated that 85% of the dams in the U.S. will be near the end of their operational lives by the year 2020 (FEMA, 1999), necessitating thorough consideration of dam removal or repair for…