Effects of hydrocarbon contamination on soil microbial community and enzyme activity

Acknowledgment I would like to gratefully acknowledge the government of Saudi Arabia for the scholarship and financial support.Peer reviewedPublisher PD

Uses of Key Species, Key Areas And Utilization Standards in Range Management

The importance of proper management of the nation’s 728 million acres of range lands has received greatly increased recognition during the past five years. Many new developments pertaining to the range have occurred and a number of new agencies have entered the field. Soil conservation and flood control measures have been undertaken on vast acreages of depleted grazing land. Control is rapidly being extended over the one-time open public domain. Research projects involving both forage and watershed problems have been expanded on winter, spring-fall, and summer range areas. Numerous studies of the social and economic aspects of range use have been initiated with both state and federal agencies participating. Under the Agricultural Adjustment Act, benefit payments have been made during 1936 and 1937 for improved management practices on over 50 million acres of range land. Range problems are being given serious consideration by regional, state and county planning agencies

Investigating soil-water retention characteristics at high suctions using Relative Humidity control

A technique for controlling relative humidity (RH) is presented, which involves supplying a sealed chamber with a continuous flow of air at a computer-regulated RH. The desired value of RH is achieved by mixing dry and wet air at appropriate volumes and is measured for servo-control at three locations in the chamber with capacitive RH sensors and checked with a sensitive VAISALA sensor. The setup is capable of controlling RH steadily and continuously with a deviation of less than 0.2% RH. The technique was adopted to determine wetting soil-water retention curves (SWRC) of statically compacted London Clay, under both free-swelling and constant volume conditions. The RH within the chamber was increased in a step-wise fashion, with each step maintained until vapour equilibrium between the chamber atmosphere and the soil samples was established. Independent filter paper measurements further validate the method, while the obtained retention curves complement those available in the literature for lower ranges of suction

The Australian Charter of Employment Rights: The missing dimensions

Just prior to the 2007 General Election, a group of labour lawyers and economists, broadly sympathetic to the Labor Party, produced a Charter of Employment Rights. This article examines the Charter's proposals and its underlying framework, and suggests significant aspects of work and labour have been omitted. It contends that the Charter would have been improved if it had not retained an artificially stretched definition of workers as employees, in which the only relationship worthy of inclusion in a Charter is that between the direct employer and employee. The framework and language of the Charter convey a paternalistic approach and an outdated focus on industrial labour, while ignoring aspects of the emerging global system of work linked to the concept of occupation

Swelling behaviour of an expansive clay at high suction

Deep geological disposal designs for nuclear waste often include an engineered barrier to protect the waste canisters and prevent leakage . The long - term safety of the re pository relies on studies of the buffer material . Oedometer tests provide values of de sign parameters for numerical simulations. A newly - developed oedometer with automated suction control is presented to assist in the investigation of the coupled hydro - me- chanical - volumetric behaviour of an expansive clay, namely a natural sodium bentonite. The displacement - controlled device was developed to apply suction over a range of 1 0 MPa to 300 MPa using a divided - flow humidity - generator. The device allows the application of combined stress and suction states, and continuous stress paths of constant vo lume, stress or suction. The development of the new oedometer is described. Results obtained during the preliminary tests are evaluated through comparison with experimental data from similar tests found in the literature. The current method benefits from c ontinuous control of suction with servo - control of relative humidity using calibrated capacitance hygrometers. The system self - compensates for minor temper- ature changes and therefore the requirement for thermal insulation is not as crucial as in vapour equ ilibrium methods

Ground-state cooling of a trapped ion Using long-wavelength radiation

We demonstrate ground-state cooling of a trapped ion using radio-frequency (rf) radiation. This is a powerful tool for the implementation of quantum operations, where rf or microwave radiation instead of lasers is used for motional quantum state engineering. We measure a mean phonon number of n¯=0.13(4) after sideband cooling, corresponding to a ground-state occupation probability of 88(7)%. After preparing in the vibrational ground state, we demonstrate motional state engineering by driving Rabi oscillations between the |n=0⟩ and |n=1⟩ Fock states. We also use the ability to ground-state cool to accurately measure the motional heating rate and report a reduction by almost 2 orders of magnitude compared with our previously measured result, which we attribute to carefully eliminating sources of electrical noise in the system

Investigating the effect of tunnelling on existing tunnels

A major research project investigating the effect of tunnelling on existing tunnels has been completed at Imperial College London. This subject is always of great concern during the planning and execution of underground tunnelling works in the urban environment. Many cities already have extensive existing tunnel networks and so it is necessary to construct new tunnels at a level beneath them. The associated deformations that take place during tunnelling have to be carefully assessed and their impact on the existing tunnels estimated. Of particular concern is the serviceability of tunnels used for underground trains where the kinematic envelope must not be impinged upon. The new Crossrail transport line under construction in London passes beneath numerous tunnels including a number of those forming part of the London Underground networ

The dental lamina: an essential structure for perpetual tooth regeneration in sharks

In recent years non-classical models have emerged as mainstays for studies of evolutionary, developmental and regenerative biology. Genomic advances have promoted the use of alternative taxa for the study of developmental biology, and the shark is one such emerging model vertebrate. Our research utilizes the embryonic shark (Scyliorhinus canicula) to characterize key developmental and regenerative processes that have been overlooked or not possible to study with more classic developmental models. Tooth development is a major event in the construction of the vertebrate body plan, linked in part with the emergence of jaws. Early development of the teeth and morphogenesis is well known from the murine model, but the process of tooth redevelopment and regeneration is less well known. Here we explore the role of the dental lamina in the development of a highly regenerative dentition in sharks. The shark represents a polyphyodont vertebrate with continuously repeated whole tooth regeneration. This is presented as a major developmental shift from the more derived renewal process that the murine model offers, where incisors exhibit continuous renewal and growth of the same tooth. Not only does the shark offer a study system for whole unit dental regeneration, it also represents an important model for understanding the evolutionary context of vertebrate tooth regeneration

Benefit-Cost Meta-Analysis of Investment in the International Agricultural Research Centers of the CGIAR

This study was undertaken by David Raitzer, on behalf of the CGIAR Standing Panel on Impact Assessment. The author addresses the question: do the documented benefits from CGIAR research justify the total investment in the CGIAR so far? The basic objective of the study is to derive a set of plausible and highly credible aggregate estimates of the benefits accruing from System innovations, and to set such against the present value of the entire CGIAR expenditure. The study contains several figures and tables. The forward was written by Hans Gregersen, Chair of the Standing Panel on Impact Assessment