Irrigation efficiency and water-policy implications for river-basin resilience

Rising demand for food, fiber, and biofuels drives expanding irrigation withdrawals from surface water and groundwater. Irrigation efficiency and water savings have become watchwords in response to climate-induced hydrological variability, increasing freshwater demand for other uses including ecosystem water needs, and low economic productivity of irrigation compared to most other uses. We identify three classes of unintended consequences, presented here as paradoxes. Ever-tighter cycling of water has been shown to increase resource use, an example of the efficiency paradox. In the absence of effective policy to constrain irrigated-area expansion using "saved water", efficiency can aggravate scarcity, deteriorate resource quality, and impair river basin resilience through loss of flexibility and redundancy. Water scarcity and salinity effects in the lower reaches of basins (symptomatic of the scale paradox) may partly be offset over the short-term through groundwater pumping or increasing surface water storage capacity. However, declining ecological flows and increasing salinity have important implications for riparian and estuarine ecosystems and for non-irrigation human uses of water including urban supply and energy generation, examples of the sectoral paradox. This paper briefly considers three regional contexts with broadly similar climatic and water-resource conditions – central Chile, southwestern US, and south-central Spain – where irrigation efficiency directly influences basin resilience. The comparison leads to more generic insights on water policy in relation to irrigation efficiency and emerging or overdue needs for environmental protection.

A Wireless Charging System Applying Phase-Shift and Amplitude Control to Maximize Efficiency and Extractable Power

Wireless power transfer (WPT) is an emerging technology with an increasing number of potential applications to transfer power from a transmitter to a mobile receiver over a relatively large air gap. However, its widespread application is hampered due to the relatively low efficiency of current Wireless power transfer (WPT) systems. This study presents a concept to maximize the efficiency as well as to increase the amount of extractable power of a WPT system operating in nonresonant operation. The proposed method is based on actively modifying the equivalent secondary-side load impedance by controlling the phase-shift of the active rectifier and its output voltage level. The presented hardware prototype represents a complete wireless charging system, including a dc-dc converter which is used to charge a battery at the output of the system. Experimental results are shown for the proposed concept in comparison to a conventional synchronous rectification approach. The presented optimization method clearly outperforms state-of-the-art solutions in terms of efficiency and extractable power.

The effect of flow speed and food size on the capture efficiency and feeding behaviour of the cold-water coral Lophelia pertusa

Acknowledgements The authors acknowledge L. Wicks and B. de Francisco for helping in coral sampling and coral care in the aquaria facilities at SAMS. Thanks to C. Campbell and the CCAP for kind support and help. Scientific party and crew on board the RVs Calanus and Seol Mara, as well as on board the RRS James Cook during the Changing Oceans cruise (JC_073) are greatly acknowledged. Thanks to colleagues at SAMS for their support during our stay at SAMS. We are in debt with A. Olariaga for his help modifying the cylindrical experimental chambers used in the experiments, and C.C. Suckling for assistance with the flume experiment. Many thanks go to G. Kazadinis for preparing the POM used in the feeding experiments. We also thank two anonymous reviewers and the editor for their constructive comments, which contribute to improve the manuscript. This work has been supported by the European Commission through two ASSEMBLE projects (grant agreement no. 227799) conducted in 2010 and 2011 at SAMS, as well as by the UK Ocean Acidification Research Programme's Benthic Consortium project (awards NE/H01747X/1 and NE/H017305/1) funded by NERC. [SS]

High phosphorylation efficiency and depression of uncoupled respiration in mitochondria under hypoxia

Mitochondria are confronted with low oxygen levels in the microenvironment within tissues; yet, isolated mitochondria are routinely studied under air-saturated conditions that are effectively hyperoxic, increase oxidative stress, and may impair mitochondrial function. Under hypoxia, on the other hand, respiration and ATP supply are restricted. Under these conditions of oxygen limitation, any compromise in the coupling of oxidative phosphorylation to oxygen consumption could accentuate ATP depletion, leading to metabolic failure. To address this issue, we have developed the approach of oxygen-injection microcalorimetry and ADP-injection respirometry for evaluating mitochondrial function at limiting oxygen supply. Whereas phosphorylation efficiency drops during ADP limitation at high oxygen levels, we show here that oxidative phosphorylation is more efficient at low oxygen than at air saturation, as indicated by higher ratios of ADP flux to total oxygen flux at identical submaximal rates of ATP synthesis. At low oxygen, the proton leak and uncoupled respiration are depressed, thus reducing maintenance energy expenditure. This indicates the importance of low intracellular oxygen levels in avoiding oxidative stress and protecting bioenergetic efficiency.

Catalytic efficiency and vitality of HIV-1 proteases from African viral subtypes

The vast majority of HIV-1 infections in Africa are caused by the A and C viral subtypes rather than the B subtype prevalent in the United States and Western Europe. Genomic differences between subtypes give rise to sequence variations in the encoded proteins, including the HIV-1 protease. Because some amino acid polymorphisms occur at sites that have been associated with drug resistance in the B subtype, it is important to assess the effectiveness of protease inhibitors that have been developed against different subtypes. Here we report the enzymatic characterization of HIV-1 proteases with sequences found in drug-naïve Ugandan adults. The A protease used in these studies differs in seven positions (I13V/E35D/M36I/R41K/R57K/H69K/L89M) in relation to the consensus B subtype protease. Another protease containing a subset of these amino acid polymorphisms (M36I/R41K/H69K/L89M), which are found in subtype C and other HIV subtypes, also was studied. Both proteases were found to have similar catalytic constants, kcat, as the B subtype. The C subtype protease displayed lower Km values against two different substrates resulting in a higher (2.4-fold) catalytic efficiency than the B subtype protease. Indinavir, ritonavir, saquinavir, and nelfinavir inhibit the A and C subtype proteases with 2.5–7-fold and 2–4.5-fold weaker Kis than the B subtype. When all factors are taken into consideration it is found that the C subtype protease has the highest vitality (4–11 higher than the B subtype) whereas the A subtype protease exhibits values ranging between 1.5 and 5. These results point to a higher biochemical fitness of the A and C proteases in the presence of existing inhibitors.

Sematech: Purpose and Performance

In previous research, we have found a steep learning curve in the production of semiconductors. We estimated that most production knowledge remains internal to the firm, but that a significant fraction “spills over” to other firms. The existence of such spillovers may justify government actions to stimulate research on semiconductor manufacturing technology. The fact that not all production knowledge spills over, meanwhile, creates opportunities for firms to form joint ventures and slide down their learning curves more efficiently. With these considerations in mind, in 1987 14 leading U.S. semiconductor producers, with the assistance of the U.S. government in the form of $100 million in annual subsidies, formed a research and development (R&D) consortium called Sematech. In previous research, we estimated that Sematech has induced its member firms to lower their R&D spending. This may reflect more sharing and less duplication of research, i.e., more research being done with each R&D dollar. If this is the case, then Sematech members may wish to replace any funding withdrawn by the U.S. government. This in turn would imply that the U.S. government’s contributions to Sematech do not induce more semiconductor research than would otherwise occur.

Women and Performance in Corporate America

Women and Performance in Corporate America The glass ceiling has been shattered. Women like Indra Nooyi, the CEO of PepsiCo.; Angela Braly, the CEO of Wellpoint; and Patricia Woertz, the CEO of Archer Daniels Midland, are proof that women can achieve top leadership positions in corporate America. However, the scarcity of female leaders occupying the top ranks of corporate America, and the significant wage gap between men and women, suggest that there are significant complications along the path toward success for women in the corporate world.The data show that a disproportionately small number of women are making it to top leadership positions in corporate America. According to the US Department of Labor, in 2007 women accounted for 46% of the total work force, and 51 % of all workers in management, professional, and related occupations. Women outnumbered men in occupations including financial managers, human resource managers, education administrators, medical and health service managers, accountants and auditors, budget analysts, and property, real estate, and social and community association managers (US Department of Labor, 2007). However, women hold only 15.2% of board director positions, 15.7% of corporate officer positions, and 6.2% of top earner positions (Catalyst, 2009b). Additionally, according to a 2008 Corporate Library survey, only 2.6% of Fortune 500 companies currently have female CEOs (as cited in Jones, 2009).The data also show that women earn less than men in the work force. The US Department of Labor found that women working full time in 2007 made only 80% of the salaries of men (US Department of Labor, 2008). Studies designed to control for factors other than gender have not been able to account for the wage gap between men and women (Eagly & Carli, 2007, US Government Accountability Office, 2003). Even among CEO's of fortune 500 companies, female CEO's make only 85% of the salaries of male CEO's (Jones, 2009).

Participation and performance trends in 6-hour ultra-marathoners – a retrospective data analysis of worldwide participation from 1991-2010

Participation trends in 6-hour ultra-marathons held word-wide were investigated to gain basic demographic data on 6-hour ultra-marathoners and where these races took place. Participation trends and the association between nationality and race performance were investigated in all 6-hour races held worldwide between 1991 and 2010. Participation increased linearly in both women and men across years. The annual number of finishes was significantly higher in men than in women (P=0.013). The male-to-female ratio remained stable at ~4 since 1991. Runners in age group 45-49 years showed the largest increase in participation for both men (800 participants in 18 years) and women (208 participants in 16 years). Europe attracted most of the runners from other continents (166 runners), more than all other continents combined (55 runners). European runners also showed the best top ten performances (73±3 km for women and 77±11 km for men), while African (with 65±9 km for men) and South American (54±4 km for women and 65±2 km for men) runners showed the weakest. To summarize, participation in 6-hour ultra-marathons increased across years. Most of the development took place in Europe and in athletes in the age group 45-49 years. Europe also attracted the most diverse field of athletes with runners from all other continents. European runners accounted for the most runners and achieved the best top ten performances.

Are drawings dead? …and performance over aesthetics?

When the act of 'drawing' became what can only be called formalised, (whose growth can be said to have blossomed during the Renaissance), there developed a separation between the drawing and its procurement. Recently, David Ross Scheer, in his book ‘The Death of Drawing, Architecture in the Age of Simulation’ wrote: ‘…whereas architectural drawings exist to represent construction, architectural simulations exist to anticipate building performance.’ Meanwhile, Paolo Belardi, in his work ‘Why Architects Still Draw’ likens a drawing to an acorn, where he says: ‘It is the paradox of the acorn: a project emerges from a drawing – even from a sketch, rough and inchoate - just as an oak tree emerges from an acorn.’ He tells us that Giorgio Vasari would work late at night ‘seeking to solve the problems of perspective’ and he makes a passionate plea that this reflective process allows the concept to evolve, grow and/or develop. However, without belittling Belardi, the virtual model now needs this self-same treatment where it is nurtured, coaxed and encouraged to be the inchoate blueprint of the resultant oak tree. The model now too can embrace the creative process going through the first phase of preparation, where it focuses on the problem. The manipulation of the available material can then be incubated so that it is reasoned and generates feedback. This paper serves to align this shift in perception, methodologies and assess whether the 2D paper abstraction still has a purpose and role in today’s digital world!

Is video-case an efficient tool to complement the practical learning in real contexts? Effects on satisfaction and performance in Social Work Degree students

Este documento es un artículo inédito que ha sido aceptado para su publicación. Como un servicio a sus autores y lectores, Alternativas. Cuadernos de trabajo social proporciona online esta edición preliminar. El manuscrito puede sufrir alteraciones tras la edición y corrección de pruebas, antes de su publicación definitiva. Los posibles cambios no afectarán en ningún caso a la información contenida en esta hoja, ni a lo esencial del contenido del artículo.

Überlegungen zu Ressourceneffizienz und Recycling = Reflections on resource efficiency and recycling. Research Paper in Law 6/2003

No abstract.