Generation of inertia-gravity waves in the rotating thermal annulus by a localised boundary layer instability

Waves with periods shorter than the inertial period exist in the atmosphere (as inertia-gravity waves) and in the oceans (as Poincaré and internal gravity waves). Such waves owe their origin to various mechanisms, but of particular interest are those arising either from local secondary instabilities or spontaneous emission due to loss of balance. These phenomena have been studied in the laboratory, both in the mechanically-forced and the thermally-forced rotating annulus. Their generation mechanisms, especially in the latter system, have not yet been fully understood, however. Here we examine short period waves in a numerical model of the rotating thermal annulus, and show how the results are consistent with those from earlier laboratory experiments. We then show how these waves are consistent with being inertia-gravity waves generated by a localised instability within the thermal boundary layer, the location of which is determined by regions of strong shear and downwelling at certain points within a large-scale baroclinic wave flow. The resulting instability launches small-scale inertia-gravity waves into the geostrophic interior of the flow. Their behaviour is captured in fully nonlinear numerical simulations in a finite-difference, 3D Boussinesq Navier-Stokes model. Such a mechanism has many similarities with those responsible for launching small- and meso-scale inertia-gravity waves in the atmosphere from fronts and local convection.

A method for merging flow-dependent forecast error statistics from an ensemble with static statistics for use in high resolution variational data assimilation

The background error covariance matrix, B, is often used in variational data assimilation for numerical weather prediction as a static and hence poor approximation to the fully dynamic forecast error covariance matrix, Pf. In this paper the concept of an Ensemble Reduced Rank Kalman Filter (EnRRKF) is outlined. In the EnRRKF the forecast error statistics in a subspace defined by an ensemble of states forecast by the dynamic model are found. These statistics are merged in a formal way with the static statistics, which apply in the remainder of the space. The combined statistics may then be used in a variational data assimilation setting. It is hoped that the nonlinear error growth of small-scale weather systems will be accurately captured by the EnRRKF, to produce accurate analyses and ultimately improved forecasts of extreme events.

Storm surge frequency reduction in Venice under climate change

Increased tidal levels and storm surges related to climate change are projected to result in extremely adverse effects on coastal regions. Predictions of such extreme and small-scale events, however, are exceedingly challenging, even for relatively short time horizons. Here we use data from observations, ERA-40 reanalysis, climate scenario simulations, and a simple feature model to find that the frequency of extreme storm surge events affecting Venice is projected to decrease by about 30% by the end of the twenty-first century. In addition, through a trend assessment based on tidal observations we found a reduction in extreme tidal levels. Extrapolating the current +17 cm/century sea level trend, our results suggest that the frequency of extreme tides in Venice might largely remain unaltered under the projected twenty-first century climate simulations.

The Stonehenge landscape habitat restoration project: conservation opportunities for rare butterflies?

Landscape restoration has the potential to mitigate habitat loss and fragmentation. However, restoration can take decades to reach the ecological conditions of the target habitats. The National Trust’s Stonehenge Landscape Restoration Project provides an opportunity to evaluate the ecological benefits against the economic and temporal costs. A field survey between June and September 2010 using Lepidoptera as bio-indicators showed that restored grasslands can approach the ecological conditions of the target chalk grassland habitat within 10 years. However, specialist species like Lysandra bellargus (Adonis blue) were absent from restored grasslands and may require additional management to assist their colonisation. Analysis of the Lepidoptera communities showed that both small-scale habitat heterogeneity and age of the habitat were important for explaining Lepidoptera occurrence. These results demonstrate that habitat restoration at the landscape scale combined with appropriate site-scale management can be a relatively rapid and effective method to restore ecological networks and buffer against future climate change.

Reduced space optimal interpolation of daily rain gauge precipitation in Switzerland

The coarse spacing of automatic rain gauges complicates near-real- time spatial analyses of precipitation. We test the possibility of improving such analyses by considering, in addition to the in situ measurements, the spatial covariance structure inferred from past observations with a denser network. To this end, a statistical reconstruction technique, reduced space optimal interpolation (RSOI), is applied over Switzerland, a region of complex topography. RSOI consists of two main parts. First, principal component analysis (PCA) is applied to obtain a reduced space representation of gridded high- resolution precipitation fields available for a multiyear calibration period in the past. Second, sparse real-time rain gauge observations are used to estimate the principal component scores and to reconstruct the precipitation field. In this way, climatological information at higher resolution than the near-real-time measurements is incorporated into the spatial analysis. PCA is found to efficiently reduce the dimensionality of the calibration fields, and RSOI is successful despite the difficulties associated with the statistical distribution of daily precipitation (skewness, dry days). Examples and a systematic evaluation show substantial added value over a simple interpolation technique that uses near-real-time observations only. The benefit is particularly strong for larger- scale precipitation and prominent topographic effects. Small-scale precipitation features are reconstructed at a skill comparable to that of the simple technique. Stratifying the reconstruction method by the types of weather type classifications yields little added skill. Apart from application in near real time, RSOI may also be valuable for enhancing instrumental precipitation analyses for the historic past when direct observations were sparse.

English teachers in the digital age – a case study of policy and expert practice from England

This article is a case study of how English teachers in England have coped with the paradigm shift from print to digital literacy. It reviews a large scale national initiative that was intended to upskill all teachers, considers its weak impact and explores the author’s involvement in the evaluation of the project’s direct value to English teachers. It explores how this latter evaluation revealed how best practice in English using ICT was developing in a variable manner. It then reports on a recent small scale research project that investigated how very good teachers have adapted ICT successfully into their teaching. It focuses on how the English teachers studied in the project are developing a powerful new pedagogy situated in the life worlds of their students and suggests that this model may be of benefit to many teachers. The issues this article reports on have resonance in all English speaking countries. This article is also a personal story of the author’s close involvement with ICT and English over 20 years, and provides evidence for his conviction that digital technologies will eventually transform English teaching.

In vitro fermentation by human gut bacteria of proteolytically digested caseinomacropeptide nonenzymatically glycosylated with prebiotic carbohydrates

The in vitro fermentation selectivity of hydrolyzed caseinomacropeptide (CMP) glycosylated, via Maillard reaction (MR), with lactulose, galacto-oligosaccharides from lactose (GOSLa), and galacto-oligosaccharides from lactulose (GOSLu) was evaluated, using pH-controlled small-scale batch cultures at 37 °C under anaerobic conditions with human feces. After 10 and 24 h of fermentation, neoglyconjugates exerted a bifidogenic activity, similar to those of the corresponding prebiotic carbohydrates. No significant differences were found in Bacteroides, Lactobacillus�Enterococcus, Clostridium histolyticum subgroup, Atopobium and Clostridium coccoides�Eubacterium rectale populations. Concentrations of lactic acid and short-chain fatty acids (SCFA) produced during the fermentation of prebiotic carbohydrates were similar to those produced for their respective neoglycoconjugates at both fermentation times. These findings, joined with the functional properties attributed to CMP, could open up new applications of MR products involving prebiotics as novel multiple-functional ingredients with potential beneficial effects on human health.

In vitro fermentation of alternansucrase raffinose-derived oligosaccharides by human gut bacteria

In this work, in vitro fermentation of alternansucrase raffinose-derived oligosaccharides, previously fractionated according to their degree of polymerization (DP; from DP4 to DP10), was carried out using small-scale pH-controlled batch cultures at 37 °C under anaerobic conditions with human feces. Bifidogenic activity of oligosaccharides with DP4�6 similar to that of lactulose was observed; however, in general, a significant growth of lactic acid bacteria Bacteroides, Atopobium cluster, and Clostridium histolyticum group was not shown during incubation. Acetic acid was the main short chain fatty acid (SCFA) produced during the fermentation process; the highest levels of this acid were shown by alternansucrase raffinose acceptor pentasaccharides at 10 h (63.11 mM) and heptasaccharides at 24 h (54.71 mM). No significant differences between the gas volume produced by the mixture of raffinose-based oligosaccharides (DP5�DP10) and inulin after 24 h of incubation were detected, whereas lower gas volume was generated by DP4 oligosaccharides. These findings indicate that novel raffinose-derived oligosaccharides (DP4�DP10) could be a new source of prebiotic carbohydrates.

'Agricultural poverty' and the expansion of artisanal mining in sub-Saharan Africa: Experiences from southwest Mali and southeast Ghana

Why do people engage in artisanal and small-scale mining (ASM) – labour-intensive mineral extraction and processing activity – across sub-Saharan Africa? This paper argues that ‘agricultural poverty’, or hardship induced by an over-dependency on farming for survival, has fuelled the recent rapid expansion of ASM operations throughout the region. The diminished viability of smallholder farming in an era of globalization and overreliance on rain-fed crop production restricted by seasonality has led hundreds of thousands of rural African families to ‘branch out’ into ASM, a move made to secure supplementary incomes. Experiences from Komana West in Southwest Mali and East Akim District in Southeast Ghana are drawn upon to illustrate how a movement into the ASM economy has impacted farm families, economically, in many rural stretches of sub-Saharan Africa.

Safeguarding livelihoods or exacerbating poverty?: Artisanal mining and formalization in West Africa

In recent years, policy mechanisms to support a formalized artisanal and small-scale mining (ASM) sector in sub-Saharan Africa have gained increasing currency. Proponents of formalization argue that most social and environmental problems associated with the sector stem from the fact that ASM is predominantly unregulated and operates outside the legal sphere. This paper critically examines recent efforts to formalize artisanal and small-scale mining inWest Africa, drawing upon recent fieldwork carried out in Sierra Leone, Ghana and Mali. In exploring the sector’s livelihood dimensions, the analysis suggests that bringing unregulated, informal mining activities into the legal domain remains a considerable challenge. The paper concludes by confirming the urgent need to refocus formalization strategies on the main livelihood challenges and constraints of small-scale miners themselves, if poverty is to be alleviated and more benefits are to accrue to depressed communities in mineral-rich regions.

Strengthening artisanal mining research and policy through baseline census activities

Over the past 10-15 years, several governments have implemented an array of technology, support-related, sustainable livelihoods (SL) and poverty-reduction projects for artisanal and small-scale mining (ASM). In the majority of cases, however, these interventions have failed to facilitate improvements in the industry's productivity and raise the living standards of the sector's subsistence operators. This article argues that a poor understanding of the demographics of target populations has precipitated these outcomes. In order to strengthen policy and assistance in the sector, governments must determine, with greater precision, the number of people operating in ASM regions, their origins and ethnic backgrounds, ages, and educational levels. This can be achieved by carrying out basic and localized census work before promoting ambitious sector-specific projects aimed at improving working conditions in the industry.

Structural adjustment and subsistence industry: artisanal gold mining in Ghana

Since the implementation of Ghana's national Structural Adjustment Programme (SAP), policies associated with the programme have been criticized for perpetuating poverty within the country's subsistence economy. This article brings new evidence to bear on the contention that the SAP has both fuelled the uncontrolled growth of informal, poverty-driven artisanal gold mining and further marginalized its impoverished participants. Throughout the adjustment period, it has been a central goal of the government to promote the expansion of large-scale gold mining through foreign investment. Confronted with the challenge of resuscitating a deteriorating gold mining industry, the government introduced a number of tax breaks and policies in an effort to create an attractive investment climate for foreign multinational mining companies. The rapid rise in exploration and excavation activities that has since taken place has displaced thousands of previously-undisturbed subsistence artisanal gold miners. This, along with a laissez faire land concession allocation procedure, has exacerbated conflicts between mining parties. Despite legalizing small-scale mining in 1989, the Ghanaian government continues to implement procedurally complex and bureaucratically unwieldy regulations and policies for artisanal operators which have the effect of favouring the interests of established large-scale miners.

Changing standards revisited: children’s awareness and knowledge of features of written standard English at ages 10-11

This paper reports the findings of a small-scale research project which investigated the levels of awareness and knowledge of written standard English of 10 and 11 year old children in two English primary schools. The project involved repeating in 2010 a written questionnaire previously used with children in the same schools in three separate surveys in 1999, 2002 and 2005. Data from the latest survey are compared to those from the previous three. The analysis seeks to identify any changes over time in children’s ability to recognise non-standard forms and supply standard English alternatives, as well as their ability to use technical terms related to language variation. Differences between the performance of boys and girls and that of the two schools are also analysed. The paper concludes that the socio-economic context of the schools may be a more important factor than gender in variations over time identified in the data.

Upper-ocean heat budget and ocean eddy transport in the south-east Pacific in a high-resolution coupled model

We present an analysis of the oceanic heat advection and its variability in the upper 500 m in the southeastern tropical Pacific (100W–75W, 25S–10S) as simulated by the global coupled model HiGEM, which has one of the highest resolutions currently used in long-term integrations. The simulated climatology represents a temperature advection field arising from transient small-scale (<450 km) features, with structures and transport that appear consistent with estimates based on available observational data for the mooring at 20S, 85W. The transient structures are very persistent (>4 months), and in specific locations they generate an important contribution to the local upper-ocean heat budget, characterised by scales of a few hundred kilometres, and periods of over a year. The contribution from such structures to the local, long-term oceanic heat budget however can be of either sign, or vanishing, depending on the location; and, although there appears some organisation in preferential areas of activity, the average over the entire region is small. While several different mechanisms may be responsible for the temperature advection by transients, we find that a significant, and possibly dominant, component is associated with vortices embedded in the large-scale, climatological salinity gradient associated with the fresh intrusion of mid-latitude intermediate water which penetrates north-westward beneath the tropical thermocline

Farm and socio-economic characteristics of smallholder milk producers and their influence on technology adoption in Central Mexico

In order to identify the factors influencing adoption of technologies promoted by government to small-scale dairy farmers in the highlands of central Mexico, a field survey was conducted. A total of 115 farmers were grouped through cluster analysis (CA) and divided into three wealth status categories (high, medium and low) using wealth ranking. Chi-square analysis was used to examine the association of wealth status with technology adoption. Four groups of farms were differentiated in terms of farms’ dimensions, farmers’ education, sources of incomes, wealth status, management of herd, monetary support by government and technological availability. Statistical differences (p < 0.05) were observed in the milk yield per herd per year among groups. Government organizations (GO) participated little in the promotion of the 17 technologies identified, six of which focused on crop or forage production and 11 of which were related to animal husbandry. Relatives and other farmers played an important role in knowledge diffusion and technology adoption. Although wealth status had a significant association (p < 0.05) with adoption, other factors including importance of the technology to farmers, usefulness and productive benefits of innovations together with farmers’ knowledge of them, were important. It is concluded that the analysis of the information per group and wealth status was useful to identify suitable crop or forage related and animal husbandry technologies per group and wealth status of farmers. Therefore the characterizations of farmers could provide a useful starting point for the design and delivery of more appropriate and effective extension.