Redox Stratification and Salinization of Three Kettle Lakes in Southwest Michigan,USA

Redox stratification, especially hypolimnetic anoxia resulting from eutrophication, and salinization resulting from application of salts for road deicing is investigated in three kettle lakes in southwest Michigan. Two of the lakes (Asylum and Woods Lakes) are located in urban Kalamazoo, Michigan, and the third (Brewster Lake) is located in rural Hastings, Michigan. In summer, the water columns of all three lakes are distinctly redox stratified, with anoxic hypolimnia and significant accumulation of reduced solutes (e.g., Mn(II), Fe(II), ammonia) in the lake bottom waters. Extremely elevated conductivity, chloride, sodium, and potassium levels are observed in the urban Asylum and Woods Lakes compared to the rural Brewster Lake, presumably due to runoff of road salt deicers applied in the surrounding watershed. These significant changes in water quality are of concern because they may detrimentally impact lake mixing, biodiversity, and ecosystem function in the urban lakes.     

A dielectric omnidirectional reflector

A design criterion that permits truly omnidirectional reflectivity for all polarizations of incident light over a wide selectable range of frequencies was used in fabricating an all-dielectric omnidirectional reflector consisting of multilayer films. The reflector was simply constructed as a stack of nine alternating micrometer-thick layers of polystyrene and tellurium and demonstrates omnidirectional reflection over the wavelength range from 10 to 15 micrometers. Because the omnidirectionality criterion is general, it can be used to design omnidirectional reflectors in many frequency ranges of interest. Potential uses depend on the geometry of the system. For example, coating of an enclosure will result in an optical cavity. A hollow tube will produce a low-loss, broadband waveguide, whereas a planar film could be used as an efficient radiative heat barrier or collector in thermoelectric devices.     

闽北红壤区牧草引种与筛选研究Ⅱ.热带种

为在闽北红壤构推广种植优质牧草,１９９０年引进４０个国内外热带品种,在福建省建阳市试种。按《印尼植物基因资源田间评价》方法进行观察记载,并进行综合评价。筛选出圆叶决明,南非马唐,平托花生等３个优良多年生热带牧草品种。３个品种均表现高产,优质,圆叶决明耐瘠,抗旱力强,适宜有瘠薄的红黄壤旱地种植;     

Photoemission evidence for a remnant fermi surface and a d-wave-like dispersion in insulating Ca2CuO2Cl2

An angle-resolved photoemission study is reported on Ca2CuO2Cl2, a parent compound of high-Tc superconductors. Analysis of the electron occupation probability, n(k), from the spectra shows a steep drop in spectral intensity across a contour that is close to the Fermi surface predicted by the band calculation. This analysis reveals a Fermi surface remnant, even though Ca2CuO2Cl2 is a Mott insulator. The lowest energy peak exhibits a dispersion with approximately the &cjs3539;coskxa - coskya&cjs3539; form along this remnant Fermi surface. Together with the data from Dy-doped Bi2Sr2CaCu2O8+delta, these results suggest that this d-wave-like dispersion of the insulator is the underlying reason for the pseudo gap in the underdoped regime.     

A comprehensive approach for assessing the economic contribution of forage and livestock improvement options to smallholder farming enterprises

The importance of livestock production activities to improving the livelihoods of smallholder farming households and the efficiency of their underlying farming systems is increasingly recognized.A rapid increase in livestock numbers, especially beef cattle, and special purpose forages is being promoted for smallholder farms which have traditionally undertaken subsistence cropping activities or simple livestock rearing activities using low quality feedstuffs.Because limited plantings of specialized forages combined with a poor knowledge of animal nutrition are a challenge to establishing sustainable livestock enterprises, much public policy and research is now being focused on the use of new forages and improved feeding practices.A number of economic studies have suggested that specialized forage growing and livestock feeding activities can make a positive contribution to smallholder welfare.The studies have typically compared the total level of farm or household income with and without livestock activities.Little attention is given to how much the new forage or livestock activities actually contribute to or draw resources from other farm activities to assess their real economic contribution to the enterprise, and the availability of simple tools to assist in making such assessments are limited.This paper describes a simple modelling approach that was developed for an Australian Centre for International Agricultural Research(ACIAR)-supported project to explore the real as opposed to apparent economic impact of integrating improved forages and livestock within smallholder farming systems in the Red Soils region of south-central China.Application of the model is demonstrated using a simple case study of a smallholder enterprise that plans to introduce a new beef cattle rearing activity to its existing farm activity mix.The case study highlights the importance of explicitly valuing transfers of resources between different farm activities to gauge the real contribution of those activities to economic returns.     

Heat production by the mature male turkey (Meleagris gallopavo): preliminary measurements in an automated, indirect, open-circuit multi-calorimeter system

The energy metabolism of mature male turkeys (Meleagris gallopavo) was determined in a computer-controlled indirect multi-calorimeter system of which the design and operation are described. Daily heat production did not change significantly during an initial 6-d period in the calorimeter chambers. Food intake was at first sufficient to promote a rate of energy retention significantly greater than zero, but decreased to give negative energy retention on day 6; mean energy retention for the whole 6-day period was significantly greater than zero. Heat production was affected little by fasting for 72 h, although the respiratory quotient decreased to 0.72 within 48 h; the heat increment of feeding was therefore small (about 5% of metabolisable energy). Fasting heat production, scaled on metabolic body size (bodyweight in kg)0.75, was similar to that of mature male domestic fowl (Gallus domesticus). Heat production after refeeding was similar to that recorded during the 6 d before fasting. There was a pronounced circadian rhythmicity of heat production in both fed and fasted birds.     

Rapid monitoring of species abundance for biodiversity conservation: Consistency and reliability of the MacKinnon lists technique

Effective monitoring of biodiversity for conservation requires information on spatial and temporal variation in species’ abundances. As conservation resources are limited, monitoring methods are required that enable rapid and cost effective data collection. There are many traditional methods of estimating absolute abundance, such as territory mapping and distance sampling. However, these typically require more time, expertise and finances than are available across much of the globe. This is especially so in the tropics, where high species richness, low densities of many species and structurally complex environments also make monitoring particularly challenging. The MacKinnon lists technique is a rapid assessment methodology designed for use in species rich environments. This method is typically used to estimate species richness, but it has also been suggested that it can generate consistent abundance indices, even when observer experience and environmental conditions vary. If this suggestion is correct, the MacKinnon lists method could be used to assess spatial or temporal changes in abundance using diverse survey data. Here, we provide the first detailed assessment of intra- and inter-observer consistency of the Mackinnon List method in generating species abundance indices that could be useful for conservation monitoring purposes. As a case study, we use one of the world’s most diverse avifaunas, that of the forested Bolivian Andes. We show that MacKinnon lists can provide species abundance indices that are consistent between observers of markedly different experience of the focal avifauna (zero to six years), and between assessments carried out in different stages of the breeding season, between which detectability of individuals differed significantly. We believe this is the first time that a biodiversity monitoring method has been demonstrated to produce consistent abundance indices for a highly diverse avian tropical assemblage. We also suggest that the MacKinnon lists methodology has the potential to be a very useful conservation monitoring tool for many taxa in species rich environments, such as the tropics.     

A participatory, farming systems approach to improving Bali cattle production in the smallholder crop-livestock systems of Eastern Indonesia

Bali cattle (Bos javanicus) account for about one quarter of the total cattle population in Indonesia and are particularly important in the smallholder farming enterprises of the eastern islands. The population of Bali cattle is declining in most areas of Eastern Indonesia because demand for beef cattle exceeds the local capacity to supply these animals. Indonesian agencies recognise that new strategies are required to improve the productivity of Bali cattle and to address major constraints relating to animal husbandry and nutrition. To date, the adoption of cattle improvement technologies has been historically slow in Indonesia, as is the case elsewhere.This paper reports on key findings from a long-term study conducted between 2001 and 2009 with smallholder households from six villages in South Sulawesi and Central Lombok, to develop and test an approach for evaluating and increasing the adoption of cattle and forage improvement technologies. The approach is based on the principles of farming systems and participatory research and involved four main steps; (1) benchmarking the current farming system; (2) identifying constraints to cattle production and strategies to address them; (3) desktop modelling of the production and economic impacts of selected strategies; and (4) on-farm testing of the most promising strategies with 30 participant smallholder households.The approach was found to be successful based on: (1) sustained adoption of a package of best-bet technologies by the 30 participating households; (2) evidence of positive production, social and economic impacts; and (3) significant diffusion of the cattle improvement technologies to other households in the project regions.     

Rod origin of prolonged afterimages

Afterimages fade against any unchanging background but generally reappear if the background changes suddenly. Under some conditions, however, a change of background color fails to revive a faded afterimage. This happens only if the interchanged backgrounds equally stimulate the rod receptors. It follows that afterimages seen under these conditions are generated by rods.     

Qualitative and quantitative strategies of thermal adaptation of grass carp (Ctenopharyngodon idella) cytoplasmic malate dehydrogenases

Malate dehydrogenase isozymes of grass carp,Ctenopharyngodon idella, were identified by mitochondrial preparation and thermal denaturation. The structural and kinetic characteristics of chromatographically separated thermostable and thermolabile cMDHs were different in (1) half-life at 42°C, 10 min and 24 h, respectively, (2) optimal substrate, oxaloacetate and malate, concentrations, and (3) the apparent Michaelis-Menten constants of NADH and oxaloacetate.Total MDH activity in white muscle of 11°C-acclimated fish was about twice that of the 30°C-acclimated group. In addition, the ratio of the thermostable to thermolabile cMDH activity in white muscle of 30°C-acclimated fish was significantly higher than that of 11°C-acclimated fish. These results suggest that temperature acclimation can induce temperature compensation in MDH activity and differential expression of thermostable and thermolabile cMDH isozymes in freshwater fish.