Improving water use efficiency under worsening scarcity: Evidence from the Middle Olifants sub-basin in South Africa

With the political changes in South Africa in the early 1990s, the South African government introduced a reform process in the entire water sector with the goal of a more enhanced and equitable water management system. This paper analyzes existing water allocation situations and applies a nonlinear optimization model to investigate the optimal intra- and inter-regional allocations in the Middle Olifants sub-basin of South Africa. Results show higher benefit from inter-regional water allocation. Reducing water supply levels to conform to the sustainable water supply policy, it can be shown that although water supply is reduced by approximately 50%, total benefits from water are only reduced by 5% and 11% for inter- and intra-regional allocation regimes respectively. These results indicate that alternative water allocation mechanisms can serve as instruments to offset for the effects of water scarcity.Water allocation, IWRM, Olifants basin, South Africa, Africa, Resource /Energy Economics and Policy,

An evaluation of curriculum-related specialties in grades five and six

Thesis (Ed.M.)--Boston Universit

Improving water use efficiency under worsening scarcity : Evidence from the Middle Olifants sub-basin in South Africa

With the political changes in South Africa in the early 1990s, the South African government introduced a reform process in the entire water sector with the goal of a more enhanced and equitable water management system. This paper analyzes existing water allocation situations and applies a non-linear optimization model to investigate the optimal intra- and inter-regional allocations in the Middle Olifants sub-basin of South Africa. Results show higher benefit from inter-regional water allocation. Reducing water supply levels to conform to the sustainable water supply policy, it can be shown that although water supply is reduced by approximately 50%, total benefits from water are only reduced by 5% and 11% for inter- and intra-regional allocation regimes respectively. These results indicate that alternative water allocation mechanisms can serve as instruments to offset for the effects of water scarcity

Status of Agricultural Soil Contamination by Heavy Metals in Uasin Gishu County

Heavy metals occur naturally in the environment but anthropogenic activities such as use of chemicals and inorganic fertilizers in farms has resulted in higher concentrations of these metals relative to their normal background values leading to environmental pollution. Soil plays a central role in food safety as it determines the possible composition of food and feed at the root of the food chain. Soil pollution by heavy metals has been on the increase with its main sources being application of agricultural chemicals, improper disposal of industrial wastes, among others. This study investigated different concentrations of the heavy metals in soils of farms during the two major crop seasons in Uasin Gishu County, Kenya. The presences of heavy metals (Lead, Copper, Cadmium, Cobalt and Zinc) were determined in the three agro-ecological zones in Uasin Gishu County. These agro-ecological zones include Lower highland (LH3), Upper midland (UH4) and Upper midland (UH2). Soil samples from randomly selected farmers in the study area at the depth of 0-10cm and 10-20 cm were obtained. A total of seventy two soil samples were collected and analyzed for presence of heavy metals using ICPE-900Shimadzu inductive coupled plasma. The results obtained indicated that concentrations of the heavy metals found in soils at the three agro-ecological zones during the dry and wet seasons varied significantly.The results obtained showed that the mean concentration of Pb, Cd, Co, Zn and Cu in UH2 ranged between 12.0 –15.5ppm, 2.8–4.7 ppm, 2.5–9.5 ppm, 2.3–4.0 ppm, 8.0–16.3 ppm respectively, while in LH3 the concentration range between 10.0 –18.6 ppm, 1.8–4.8 ppm, 2.3–10.0 ppm, 2.0–17.3 ppm, 7.9–17.3 ppm respectively and finally in UH4, the mean concentrations of the five metals ranged between 10.3 –13.0ppm, 1.7–4.3 ppm, 4.0–8.5 ppm, 2.0–2.5 ppm, 7.7–16.5 ppm respectively. The level of Cd concentrations was found to exceed the WHO standard of 3mg/l in the study area. All the heavy metals concentrations varied significantly (P< 0.05) during wet and dry season indicating their mobility in the soils. The presence of heavy metals above the natural levels in the study area is attributed to sources such intensive agricultural activities. The results of this study revealed that the three agricultural zones of LH3 (Lower highland), UH4 (Upper midland) and UH2 (Upper midland) contained variable levels of heavy metals (Pb, Cd Zn, Co and Cu). The levels of heavy metals were high and may be indicative of the level of pollution resulting from farm activities in the three locations. The high level of Cadmium could be attributed to the level of use of inorganic fertilizers in the farmers fields in the study area. Keywords: Heavy metal; Agro-ecological zones; Agricultural soil; Soil depth; Uasin Gishu County

Selbstreinigende, abweisende Oberflächenbeschichtungen für den Umwelt- und Verbraucherschutz

Nowadays, the problems that come with the environmental and climate crisis and their solving are present everywhere, e.g., in politics, transport or industry. Thus, saving energy and reducing toxic and harmful products is of great importance in all sectors of our life. Various fields such as the water infrastructure or the medical sector have difficulties with contaminations on surfaces. Superhydrophobic and liquid-infused porous surface coatings provide an effective solution for both repelling the contaminants in the first place and easy cleaning afterwards. So far, developed processes are often based on toxic fluorinated compounds and harsh organic solvents, high energy consumption and complicated technologies. Hence, they contribute to the environmental pollution. In this thesis, we established a sprayable coating system which is dispersion-based, fluorine-free and curable at ambient conditions. The aqueous dispersions contained a polymeric binder, e.g., poly butyl methacrylate, and hydrophobic fumed silica, which self-organized into a hierarchically structured film (micro- and nano topography) when drying and formed a superhydrophobic coating (lotus effect) with water contact angles above 150° and contact angle hysteresis below 10°. By an additional spraying step, the coatings could be infiltrated with a lubricant and formed slippery liquid-infused porous surfaces resembling the pitcher plant characterized by low sliding angles (<5°) and contact angle hysteresis (<10°). Additionally, we present two methods depending on the used substrate that increased the adhesion and integrity of the coatings by introducing covalent bonds. The copolymerization of the poly methacrylate with 3-(trimethoxy silyl)propyl methacrylate or benzophenone methacrylate ensured crosslinking of the components and anchoring to the surface, i.e., glass or polymeric substrates, respectively. Furthermore, in another approach, we were able to exchange the synthetic components described above by renewable materials. We substituted the polymeric binder with natural drying oils, i.e., oils reacting with ambient oxygen and curing to solid materials, the synthetic lubricant with natural non-drying oils and the used surfactant with sodium oleate that can be derived from natural oils. The here presented methods provide a versatile toolbox to produce repellent surface coatings that can be adapted to the desired application. The coatings were prepared by a scalable and environmentally benign process with low climatical impact. Finally, the efficiency could be successfully shown in several application studies at different length scales and complexity of the contaminations, i.e., cement and ice adhesion, electrochemical corrosion resistance and biofouling at micro and macroscale.Heutzutage sind die Probleme und die Lösung der Umwelt- und Klimakrise überall präsent. Energieeinsparungen und die Reduzierung giftiger und schädlicher Produkte werden in allen Bereichen unseres Lebens, z.B. der Politik, dem Transport oder der Industrie, relevanter und zunehmend diskutiert. Viele Bereiche wie zum Beispiel die Wasserinfrastruktur oder der medizinische Sektor haben Schwierigkeiten mit kontaminierten Oberflächen. Superhydrophobe und rutschige Oberflächenbeschichtungen bieten eine effektive Lösung, um Verunreinigungen von vornherein abzuweisen oder sie anschließend leichter zu entfernen. Bisher entwickelte Verfahren basieren häufig auf giftigen fluorinierten Verbindungen, aggressiven organischen Lösungsmitteln und einem hohen Energieverbrauch. Die Prozesse und Endprodukte tragen daher nach wie vor zur Umweltverschmutzung und Klimakrise bei. In dieser Arbeit wurde ein sprühbares fluorfreies Beschichtungssystem, das bei Umgebungsbedingungen aushärtet, entwickelt. Die wässrigen Dispersionen enthielten ein polymeres Bindemittel, z.B. Polybutylmethacrylat, und hydrophobe pyrogene Kieselsäure, die sich beim Trocknen zu einem hierarchisch strukturierten Film (Mikro- und Nanotopografie) selbstorganisierten und eine superhydrophobe Beschichtung (Lotuseffekt) mit Wasserkontaktwinkeln über 150° und Kontaktwinkelhysteresen unter 10° bildeten. Durch einen zusätzlichen Sprühschritt konnten die Beschichtungen mit einem Lubricant infiltriert werden und bildeten rutschige, flüssigkeitsinfiltrierte, poröse Oberflächen, die die Kannenpflanze imitieren und sich durch geringe Rutschwinkel (<5°) und Kontaktwinkelhysteresen (<10°) auszeichnen. Zusätzlich werden zwei Methoden vorgestellt, die abhängig vom verwendeten Substrat die Stabilität der Beschichtungen durch kovalente Bindungen erhöhten. Die Co-Polymerisation des Polymethacrylats mit 3-(Trimethoxysilyl)-propylmethacrylat oder Benzophenonmethacrylat sorgte für die Vernetzung der Komponenten und die Verankerung auf der Oberfläche, d. h. auf Glas- bzw. Polymersubstraten. Ein weiterer Teil der Arbeit beschäftigt sich mit dem Austausch der synthetischen Komponenten durch nachwachsende Materialien. Das polymere Bindemittel wurde durch natürliche trocknende Öle, d. h. Öle, die mit Luftsauerstoff reagieren und zu festen Materialien aushärten, ersetzt und der synthetische Lubricant konnte durch natürliche, nicht-trocknende Öle ausgetauscht werden. Zusätzlich diente Natriumoleat, das aus natürlichen Ölen gewonnen werden kann, als alternatives Tensid. Die hier vorgestellten Methoden bieten eine vielseitige Toolbox für die Herstellung abweisender Oberflächenbeschichtungen für verschiedenste Anwendungen. Die Beschichtungen wurden durch ein skalierbares Verfahren mit geringer Klimabelastung hergestellt. Abschließend konnte die Wirksamkeit in mehreren Anwendungsstudien bei unterschiedlicher Komplexität der Verunreinigungen (Verringerung von Zement- und Eisanhaftung, Beständigkeit gegen elektrochemische Korrosion und Reduzierung von Biofouling im Mikro- und Makromaßstab) erfolgreich gezeigt werden

Seed physiological performance of soybeans with altered saturated fatty acid contents

Soybean (Glycine max (L.) Merr.) seeds with elevated or reduced percentages of palmitate and elevated percentages of stearate were compared with seeds of typical composition in tests for germination, seedling growth rate and leachate conductivity. In general, seeds with altered compositions did well in these physiological tests, but their vigour tended to be negatively correlated with the percentages of stearate and palmitate in various lipid classes

Probing the Earth's interior with a large-volume liquid scintillator detector

A future large-volume liquid scintillator detector would provide a high-statistics measurement of terrestrial antineutrinos originating from $\beta$-decays of the uranium and thorium chains. In addition, the forward displacement of the neutron in the detection reaction $\bar\nu_e+p\to n+e^+$ provides directional information. We investigate the requirements on such detectors to distinguish between certain geophysical models on the basis of the angular dependence of the geoneutrino flux. Our analysis is based on a Monte-Carlo simulation with different levels of light yield, considering both unloaded and gadolinium-loaded scintillators. We find that a 50 kt detector such as the proposed LENA (Low Energy Neutrino Astronomy) will detect deviations from isotropy of the geoneutrino flux significantly. However, with an unloaded scintillator the time needed for a useful discrimination between different geophysical models is too large if one uses the directional information alone. A Gd-loaded scintillator improves the situation considerably, although a 50 kt detector would still need several decades to distinguish between a geophysical reference model and one with a large neutrino source in the Earth's core. However, a high-statistics measurement of the total geoneutrino flux and its spectrum still provides an extremely useful glance at the Earth's interior.Comment: 21 pages, 9 figures. Minor changes, version accepted for publication in Astroparticle Physic

A Survey on Knowledge Management in Universities in the QS Rankings: E-learning and MOOCs

Purpose – Many public organizations are employing Information Technology “IT” in Knowledge Management “KM” (Silwattananusarn and Tuamsuk, 2012; Alavi and Leidner, 2001; Chatti et al., 2007). Within universities, the use of IT could be an enabler to create and facilitate the development of knowledge (Joia, 2000; Garcia, 2007; Tian et al., 2009; Sandelands, 1997); to improve knowledge sharing (Aurelie Bechina Arntzen et al., 2009; Alavi and Gallupe, 2003); to develop communities of practice (Adams and Freeman, 2000). In the educational organizations IT is also a tool to improve the quality of learning (EC, 2000). E-learning is based on digital technologies (Aspen Institute Italy, 2014), through multiple teaching methods (Derouin et al., 2005), as tools for KM (Wild et al., 2002). The websites of some universities allows anyone to follow free lessons, through the internet. These types of free online courses are known as Massive Open Online Courses „MOOCs“ (EC, 2014; Sinclair et al., 2015). The purpose of this study is to verify the type of teaching adopted by European universities and understand how training through e-learning can improve the processes of transmission and sharing of knowledge allowing everyone, not only to students, to take lessons through the web. Design/methodology/approach – The analysis allows detecting data on universities by region through the study of the websites of the top 100 European universities present in a ranking called Quacquarelli Symonds, “QS World University Rankings 2015/16”. The method used to collect the data was marked by the creation of a specific database in which are inserted, for each university, different information: status (public/private), size, age, number of enrolled students, references on websites. In this Excel spreadsheet was also taken into account the type of educational offer provided by each university, with particular reference to the provision of online courses and courses open to all. Originality/value – The article aims to provide a detailed study on the use of technology in the educational context. The exploration allows you to design, within other universities unranked, styles of teaching online to share knowledge. Practical implications – The survey, currently, is the first step of a larger project which aims to analyse the different types of e-learning platforms used by 100 universities in the European rankings QS to make teaching online. From the results of this first phase, it has emerged that all the surveyed European universities provide training not only through classroom lessons, but also with a variety of courses through e-learning even for free through MOOCs

A Survey on Knowledge Management in Universities in the QS Rankings: E-learning and MOOCs

Purpose – Many public organizations are employing Information Technology “IT” in Knowledge Management “KM” (Silwattananusarn and Tuamsuk, 2012; Alavi and Leidner, 2001; Chatti et al., 2007). Within universities, the use of IT could be an enabler to create and facilitate the development of knowledge (Joia, 2000; Garcia, 2007; Tian et al., 2009; Sandelands, 1997); to improve knowledge sharing (Aurelie Bechina Arntzen et al., 2009; Alavi and Gallupe, 2003); to develop communities of practice (Adams and Freeman, 2000). In the educational organizations IT is also a tool to improve the quality of learning (EC, 2000). E-learning is based on digital technologies (Aspen Institute Italy, 2014), through multiple teaching methods (Derouin et al., 2005), as tools for KM (Wild et al., 2002). The websites of some universities allows anyone to follow free lessons, through the internet. These types of free online courses are known as Massive Open Online Courses „MOOCs“ (EC, 2014; Sinclair et al., 2015). The purpose of this study is to verify the type of teaching adopted by European universities and understand how training through e-learning can improve the processes of transmission and sharing of knowledge allowing everyone, not only to students, to take lessons through the web. Design/methodology/approach – The analysis allows detecting data on universities by region through the study of the websites of the top 100 European universities present in a ranking called Quacquarelli Symonds, “QS World University Rankings 2015/16”. The method used to collect the data was marked by the creation of a specific database in which are inserted, for each university, different information: status (public/private), size, age, number of enrolled students, references on websites. In this Excel spreadsheet was also taken into account the type of educational offer provided by each university, with particular reference to the provision of online courses and courses open to all. Originality/value – The article aims to provide a detailed study on the use of technology in the educational context. The exploration allows you to design, within other universities unranked, styles of teaching online to share knowledge. Practical implications – The survey, currently, is the first step of a larger project which aims to analyse the different types of e-learning platforms used by 100 universities in the European rankings QS to make teaching online. From the results of this first phase, it has emerged that all the surveyed European universities provide training not only through classroom lessons, but also with a variety of courses through e-learning even for free through MOOCs

Labelling experiments in red deer provide a general model for early bone growth dynamics in ruminants

Altres ajuts: CERCA Programme/Generalitat de CatalunyaGrowth rates importantly determine developmental time and are, therefore, a key variable of a species' life history. A widely used method to reconstruct growth rates and to estimate age at death in extant and particularly in fossil vertebrates is the analysis of bone tissue apposition rates. Lines of arrested growth (LAGs) are of special interest here, as they indicate a halt in bone growth. However, although of great importance, the time intervals between, and particularly the reason of growth arrests remains unknown. Therefore, experiments are increasingly called for to calibrate growth rates with tissue types and life history events, and to provide reliable measurements of the time involved in the formation of LAGs. Based on in vivo bone labelling, we calibrated periods of bone tissue apposition, growth arrest, drift and resorption over the period from birth to post-weaning in a large mammal, the red deer. We found that bone growth rates tightly matched the daily weight gain curve, i.e. decreased with age, with two discrete periods of growth rate disruption that coincided with the life history events birth and weaning, that were visually recognisable in bone tissue as either partial LAGs or annuli. Our study identified for the first time in a large mammal a general pattern for juvenile bone growth rates, including periods of growth arrest. The tight correlation between daily weight gain and bone tissue apposition suggests that the red deer bone growth model is valid for ruminants in general where the daily weight gain curve is comparable