Poverty traps in small-scale mining communities: the case of sub-Saharan Africa

This paper critically reflects on why, in many rural stretches of sub-Saharan Africa, scores of people engage in artisanal and small-scale mining (ASM) activity – low-tech, labour intensive mineral extraction – for lengthy periods of time. It argues that a large share of the region’s ASM operators have mounting debts which prevent them from pursuing alternative, less arduous, employment. The paper concludes with an analysis of findings from research carried out by the author in Talensi-Nabdam District, Northern Ghana, which captures the essence of the poverty trap now plaguing so many ASM communities in sub-Saharan Africa.

Liquid AP-UV-MALDI enables stable ion yields of multiply charged peptide and protein ions for sensitive analysis by mass spectrometry

In biological mass spectrometry (MS), two ionization techniques are predominantly employed for the analysis of larger biomolecules, such as polypeptides. These are nano-electrospray ionization [1, 2] (nanoESI) and matrix-assisted laser desorption/ionization [3, 4] (MALDI). Both techniques are considered to be “soft”, allowing the desorption and ionization of intact molecular analyte species and thus their successful mass-spectrometric analysis. One of the main differences between these two ionization techniques lies in their ability to produce multiply charged ions. MALDI typically generates singly charged peptide ions whereas nanoESI easily provides multiply charged ions, even for peptides as low as 1000 Da in mass. The production of highly charged ions is desirable as this allows the use of mass analyzers, such as ion traps (including orbitraps) and hybrid quadrupole instruments, which typically offer only a limited m/z range (< 2000–4000). It also enables more informative fragmentation spectra using techniques such as collisioninduced dissociation (CID) and electron capture/transfer dissociation (ECD/ETD) in combination with tandem MS (MS/MS). [5, 6] Thus, there is a clear advantage of using ESI in research areas where peptide sequencing, or in general, the structural elucidation of biomolecules by MS/MS is required. Nonetheless, MALDI with its higher tolerance to contaminants and additives, ease-of-operation, potential for highspeed and automated sample preparation and analysis as well as its MS imaging capabilities makes it an ionization technique that can cover bioanalytical areas for which ESI is less suitable. [7, 8] If these strengths could be combined with the analytical power of multiply charged ions, new instrumental configurations and large-scale proteomic analyses based on MALDI MS(/MS) would become feasible.

Mean climate and variability of the atmosphere and ocean on an aquaplanet

Numerical experiments are described that pertain to the climate of a coupled atmosphere–ocean–ice system in the absence of land, driven by modern-day orbital and CO2 forcing. Millennial time-scale simulations yield a mean state in which ice caps reach down to 55° of latitude and both the atmosphere and ocean comprise eastward- and westward-flowing zonal jets, whose structure is set by their respective baroclinic instabilities. Despite the zonality of the ocean, it is remarkably efficient at transporting heat meridionally through the agency of Ekman transport and eddy-driven subduction. Indeed the partition of heat transport between the atmosphere and ocean is much the same as the present climate, with the ocean dominating in the Tropics and the atmosphere in the mid–high latitudes. Variability of the system is dominated by the coupling of annular modes in the atmosphere and ocean. Stochastic variability inherent to the atmospheric jets drives variability in the ocean. Zonal flows in the ocean exhibit decadal variability, which, remarkably, feeds back to the atmosphere, coloring the spectrum of annular variability. A simple stochastic model can capture the essence of the process. Finally, it is briefly reviewed how the aquaplanet can provide information about the processes that set the partition of heat transport and the climate of Earth.

Field-perpendicular and field-aligned plasma flows observed by EISCAT during a prolonged period of northward IMF

The effect of a prolonged period of strongly northward Interplanetary Magnetic Field (IMF) on the high-latitude F-region is studied using data from the EISCAT Common Programme Zero mode of operation on 11–12 August 1982. The analysis of the raw autocorrelation functions is kept to the directly derived parameters Ne, Te, Ti and velocity, and limits are defined for the errors introduced by assumptions about ion composition and by changes in the transmitted power and system constant. Simple data-cleaning criteria are employed to eliminate problems due to coherent signals and large background noise levels. The observed variations in plasma densities, temperatures and velocities are interpreted in terms of supporting data from ISEE-3 and local riometers and magnetometers. Both field-aligned and field-perpendicular plasma flows at Tromsø showed effects of the northward IMF: convection was slow and irregular and field-aligned flow profiles were characteristic of steady-state polar wind outflow with flux of order 1012 m−2 s−1. This period followed a strongly southward IMF which had triggered a substorm. The substorm gave enhanced convection, with a swing to equatorward flow and large (5 × 1012 m−2 s−1), steady-state field-aligned fluxes, leading to the possibility of O+ escape into the magnetosphere. The apparent influence of the IMF over both field-perpendicular and field-aligned flows is explained in terms of the cross-cap potential difference and the location of the auroral oval.

An analysis of Samoan reaction to The Orator (O Le Tulafale)’s Fāgogo defining Samoan identity

The Orator (O Le Tulafale) was promoted as the first Samoan language film shot in Samoa with a Samoan cast and crew. Written and directed by Samoan filmmaker Tusi Tamasese, the film succeeded at several of the movie industry’s prestigious festivals. The Orator (O Le Tulafale) is about an outcast family of a dwarf (Saili), his wife and her teenage daughter. As the main protagonist, Saili battles to overcome his fears to become a chief to save his family and land. The film’s themes are courage, love, honour , as well as hypocrisy, violence, and discrimination. A backlash by Samoans was predicted ; however, the opposite occurred. This raised the following questions: first, what is it about the film causing this reaction? It is a 106 -minute film shot in Samoa about Samoans and the Samoan culture . D espite promotional claims about the film , there have been Samoan -produced films in Samoa . Secondly, to what are Samoans really responding? Is it 1) just to the film because it is about Samoa, or 2) are they responding to themselves , and how they reacted during the act of watching the film? This implies levels of reactions in the act of watching, and examining the dominant level of response is important. To explore this, t he Samoan story telling technique of Fāgogo was used to analyse the film’s narration and narrative techniques. R. Allen’s (1993, 1997) concept of projected illusion was employed to discuss the relationship between Samoans and the film developed during the act of watching. An examination of the term Samoan and a description of the framework of Fa’a Samoa (Samoan culture) were provided. Also included were discussions of memory and its impact on Samoan cultural identity. The analysis indicated that The Orator (O Le Tulafale) acted as a memory prompt through which Samoans recalled memories confirming and defining cultural bonds. These memories constituted the essence of being Samoan. These memories were awakened, and shared as oral histories as fāgogo. The receivers appeared to interpret the shared memories to create their own memories and stories to suit their contexts, according to Facebook postings. An interpretation is that the organic sharing of memories as fā gogo created a global definition of Samoan that Samoans internationally claimed.

Evaluation of a thermally driven heat pump for solar heating and cooling applications

Exploiting solar energy technology for both heating and cooling purposes has the potential of meeting an appreciable portion of the energy demand in buildings throughout the year. By developing an integrated, multi-purpose solar energy system, that can operate all twelve months of the year, a high utilisation factor can be achieved which translates to more economical systems. However, there are still some techno-economic barriers to the general commercialisation and market penetration of such technologies. These are associated with high system and installation costs, significant system complexity, and lack of knowledge of system implementation and expected performance. A sorption heat pump module that can be integrated directly into a solar thermal collector has thus been developed in order to tackle the aforementioned market barriers. This has been designed for the development of cost-effective pre-engineered solar energy system kits that can provide both heating and cooling. This thesis summarises the characterisation studies of the operation of individual sorption modules, sorption module integrated solar collectors and a full solar heating and cooling system employing sorption module integrated collectors. Key performance indicators for the individual sorption modules showed cooling delivery for 6 hours at an average power of 40 W and a temperature lift of 21°C. Upon integration of the sorption modules into a solar collector, measured solar radiation energy to cooling energy conversion efficiencies (solar cooling COP) were between 0.10 and 0.25 with average cooling powers between 90 and 200 W/m2 collector aperture area. Further investigations of the sorption module integrated collectors implementation in a full solar heating and cooling system yielded electrical cooling COP ranging from 1.7 to 12.6 with an average of 10.6 for the test period. Additionally, simulations were performed to determine system energy and cost saving potential for various system sizes over a full year of operation for a 140 m2 single-family dwelling located in Madrid, Spain. Simulations yielded an annual solar fraction of 42% and potential cost savings of €386 per annum for a solar heating and cooling installation employing 20m2 of sorption integrated collectors.

Hydropower Energy Simulation Using Mike 11 Model; A Case Study In South Germany's Small Run-Of-River Hydropower Plants

Renewable energy production is a basic supplement to stabilize rapidly increasing global energy demand and skyrocketing energy price as well as to balance the fluctuation of supply from non-renewable energy sources at electrical grid hubs. The European energy traders, government and private company energy providers and other stakeholders have been, since recently, a major beneficiary, customer and clients of Hydropower simulation solutions. The relationship between rainfall-runoff model outputs and energy productions of hydropower plants has not been clearly studied. In this research, association of rainfall, catchment characteristics, river network and runoff with energy production of a particular hydropower station is examined. The essence of this study is to justify the correspondence between runoff extracted from calibrated catchment and energy production of hydropower plant located at a catchment outlet; to employ a unique technique to convert runoff to energy based on statistical and graphical trend analysis of the two, and to provide environment for energy forecast. For rainfall-runoff model setup and calibration, MIKE 11 NAM model is applied, meanwhile MIKE 11 SO model is used to track, adopt and set a control strategy at hydropower location for runoff-energy correlation. The model is tested at two selected micro run-of-river hydropower plants located in South Germany. Two consecutive calibration is compromised to test the model; one for rainfall-runoff model and other for energy simulation. Calibration results and supporting verification plots of two case studies indicated that simulated discharge and energy production is comparable with the measured discharge and energy production respectively.

The development of the private equity industry since the 2008 financial crisis

The private equity industry was experiencing a phenomenal boom at the turn of the century but collapsed abruptly in 2008 with the onset of the financial crisis. Considered one of the worst crises since the Great Depression of the 1930s, it had sent ripples around the world threatening the collapse of financial institutions and provoking a liquidity crunch followed by a huge downturn in economic activity and recession. Furthermore, the physiognomy of the financial landscape had considerably altered with banks retracting from the lending space, accompanied by a hardening of financial regulation that sought to better contain systemic risk. Given the new set of changes and challenges that had arisen from this period of financial turmoil, private equity found itself having to question current practices and methods of operation in order to adjust to the harsh realities of a new post-apocalyptic world. Consequently, this paper goes on to explore how the private equity business, management and operation model has evolved since the credit crunch with a specific focus on mature markets such as the United States and Europe. More specifically, this paper will aim to gather insights on the development of the industry since the crisis in Western Europe through a case study approach using as a base interviews with professionals working in the industry and those external to the sector but who have/have had considerable interaction with PE players from 2007 to the present.

The economics of wage-led recovery: analysis and policy recommendations

The financial crisis and Great Recession have been followed by a jobs shortage crisis that most forecasts predict will persist for years given current policies. This paper argues for a wage-led recovery and growth program which is the only way to remedy the deep causes of the crisis and escape the jobs crisis. Such a program is the polar opposite of the current policy orthodoxy, showing how much is at stake. Winning the argument for wage-led recovery will require winning the war of ideas about economics that has its roots going back to Keynes’ challenge of classical macroeconomics in the 1920s and 1930s. That will involve showing how the financial crisis and Great Recession were the ultimate result of three decades of neoliberal policy, which produced wage stagnation by severing the wage productivity growth link and made asset price inflation and debt the engine of demand growth in place of wages; showing how wage-led policy resolves the current problem of global demand shortage without pricing out labor; and developing a detailed set of policy proposals that flow from these understandings. The essence of a wage-led policy approach is to rebuild the link between wages and productivity growth, combined with expansionary macroeconomic policy that fills the current demand shortfall so as to push the economy on to a recovery path. Both sets of measures are necessary. Expansionary macro policy (i.e. fiscal stimulus and easy monetary policy) without rebuilding the wage mechanism will not produce sustainable recovery and may end in fiscal crisis. Rebuilding the wage mechanism without expansionary macro policy is likely to leave the economy stuck in the orbit of stagnation.

Analysis an development of a prototype based on media wiki and semantic media wiki integrated with a design modeling that allows modeling of organizations based on demo

In a world where organizations are ever more complex the need for the knowledge of the organizational self is a growing necessity. The DEMO methodology sets a goal in achieving the specification of the organizational self capturing the essence of the organization in way independent of its implementation and also coherent, consistent, complete, modular and objective. But having such organization self notion is of little meaning if this notion is not shared by the organization actors. To achieve this goal in a society that has grown attached to technology and where time is of utmost importance, using a tool such as a semantic Wikipedia may be the perfect way of making the information accessible. However, to establish DEMO methodology in such platform there is a need to create bridges between its modeling components and semantic Wikipedia. It’s in that aspect that our thesis focuses, trying to establish and implement, using a study case, the principles of a way of transforming the DEMO methodology diagrams in comprehensive pages on semantic Wikipedia but keeping them as abstract as possible to allow expansibility and generalization to all diagrams without losing any valuable information so that, if that is the wish, those diagrams may be recreated from the semantic pages and make this process a full cycle.

Applying DEMO to model and automate a process in a workflow system: a case study in a city hall

Organizations are Complex systems. A conceptual model of the enterprise is needed that is: coherent the distinguished aspect models constitute a logical and truly integral comprehensive all relevant issues are covered consistent the aspect models are free from contradictions or irregularities concise no superfluous matters are contained in it essential it shows only the essence of the enterprise, i.e., the model abstracts from all realization and implementation issues. The world is in great need for transparency about the operation of all the systems we daily work with, ranging from the domestic appliances to the big societal institutions. In this context the field of enterprise ontology has emerged with the aim to create models that help to understand the essence of the construction and operation of complete systems; more specifically, of enterprises. Enterprise ontology arises in the way to look through the distracting and confusing appearance of an enterprise right into its deep kernel. This, from the perspective of the system designer gives him the tools needed to design a successful system in a way that’s reflects the desires and needs of the workers of the enterprise. This project’s context is the use of DEMO (Design and Engineering Methodology for Organizations) for (re)designing or (re)engineering of an enterprise, namely a process of the construction department of a city hall, the lack of a well-founded theory about the construction and operation of this processes that was the motivation behind this work. The purpose of studying applying the DEMO theory and method was to optimize the process, automating it as much as possible, while reducing paper and time spent between tasks and provide a better service to the citizens.

Usability of car stereo

Automotive sound systems vary widely in terms of functions and way of use between different brands and models what can bring difficulties and lack of consistency to the user. This study aimed to analyze the usability of car stereo commonly found in the market. Four products were analyzed by task analysis and after use reports and the results indicate serious usability issues with respect to the form of operation, organization, clarity and quality of information, visibility and readability, among others.

Fabrication and characterization of chemical sensors made from nanostructured films of poly(o-ethoxyaniline) prepared with different doping acids

Chemical sensors made from nanostructured films of poly(o-ethoxyaniline) POEA and poly(sodium 4-styrene sulfonate) PSS are produced and used to detect and distinguish 4 chemicals in solution at 20 mM, including sucrose, NaCl, HCl, and caffeine. These substances are used in order to mimic the 4 basic tastes recognized by humans, namely sweet, salty, sour, and bitter, respectively. The sensors are produced by the deposition of POEA/PSS films at the top of interdigitated microelectrodes via the layer-by-layer technique, using POEA solutions containing different dopant acids. Besides the different characteristics of the POEA/PSS films investigated by UV-Vis and Raman spectroscopies, and by atomic force microscopy.. it is observed that their electrical response to the different chemicals in liquid media is very fast, in the order of seconds, systematical, reproducible, and extremely dependent on the type of acid used for film fabrication. The responses of the as-prepared sensors are reproducible and repetitive after many cycles of operation. Furthermore, the use of an "electronic tongue" composed by an array of these sensors and principal component analysis as pattern recognition tool allows one to reasonably distinguish test solutions according to their chemical composition. (c) 2007 Published by Elsevier B.V.

Experimental performance of a direct evaporative cooler operating during summer in a Brazilian city

This paper presents the basic principles of the evaporative cooling process for human thermal comfort, the principles of operation for the direct evaporative cooling system and the mathematical development of the equations of thermal exchanges, allowing the determination of the effectiveness of saturation. It also presents the results of experimental tests in a direct evaporative cooler that take place in the Air Conditioning Laboratory at the University of Taubate Mechanical Engineering Department, and the experimental results are used to determinate the convective heat transfer co-efficient and to compare with the mathematical model. (c) 2005 Elsevier Ltd and IIR. All rights reserved.

A model to predict R134a refrigerant leakage through the radial clearance of rolling piston compressors

In this paper a non-isothermal two-phase model for oil-R134a refrigerant mixture flow is presented to predict the R134a leakage through the radial clearance of rolling piston compressors. The flow is divided in a liquid single-phase region and in a two-phase region, in which the homogeneous model is used to simulate the flow. The refrigerant leakage is determined using the mixture mass flow rate and the refrigerant mass fraction variation along the flow. The results are obtained for inlet pressures varying from 200 to 700 kPa, inlet temperatures ranging from 40 to 60 degrees C, and minimal clearances between 10 and 60 mu m. The results are firstly compared to existing isothermal model data, showing that there is a significant difference between the leakage flow rates predicted by isothermal and non-isothermal models. Finally, a useful general equation for compressor designers is proposed to calculate the refrigerant leakage for a large range of operation conditions. (C) 2012 Elsevier Ltd and IIR. All rights reserved.