Susceptibility indexing method for irrigation water management planning: applications to K. Menderes river basin, Turkey

A susceptibility indexing method was developed based on vulnerability and quality indices. The contamination susceptibility index (SI) at a given location was calculated by taking the product of the vulnerability index (VI) and the quality index (QI): SI = VI × QI. This method incorporates both hydrogeological and hydrochemical data for a comprehensive index mapping. The DRASTIC index methodology was used for the hydrogeological data evaluations. The quality index calculation procedure based on a water quality classification scheme was introduced to evaluate hydrochemical data. The suggested susceptibility indexing method was applied to the Küçük Menderes river basin located in western Turkey. The susceptibility index map shows both hydrogeological and hydrochemical data related to the contamination problem including areas that should be taken into consideration during water management planning. The index map indicates that the most susceptible groundwater is located along the river channel between Kiraz and Tire towns, in the Selçuk area and along the Fertek stream channel to the north of Torbal? town. The results indicate that the incorporation of both hydrogeological and hydrochemical datasets enables more realistic evaluations than those of an individual dataset to estimate the groundwater contamination susceptibility of an aquifer. The numerical procedure applied could be extended further by including other parameters such as retardation, potential contaminant sources, etc. that affect the water quality in a given basin.     

Methane oxidation in slurry storage surface crusts

Livestock manure is a significant source of atmospheric methane (CH4), especially during liquid storage. In liquid manure (slurry) storages a surface crust may form naturally, or an artificial surface crust can be established. We investigated whether there is a potential for CH4 oxidation in this environment. Surface crust materials were sampled from experimental storages with cattle slurry (with natural crust) or anaerobically digested cattle slurry (with straw layer) that had been stored with or without a wooden cover. Extracts of surface crust material were incubated with 5.6% CH4 in the headspace, and methanotrophic activity was demonstrated in all four treatments following a 4- to 10-d lag phase. Subsequent incubation of field-moist surface crust material with 350 microL L(-1) CH4 also showed CH4 oxidation, indicating a potential for CH4 removal under practical storage conditions. There was no CH4 oxidation activity during incubation of autoclaved samples. Methane oxidation rates were 0.1 to 0.5 mg kg(-1) organic matter (OM) h(-1), which is comparable with the activity in wetlands and rice paddies. Partial drying increased CH4 oxidation to 0.2 to 1.4 mg kg(-1) OM h(-1), probably as a result of improved diffusivity within the surface crust. Rewetting reversed the stimulation of methanotrophic activity in some treatments, but not in others, possibly due to a decline in CH4 production in anaerobic volumes, or to growth of methanotrophs during incubation. This study presents direct evidence for methanotrophic activity in slurry storages. Measures to ensure crust formation with or without a solid cover appear to be a cost-effective greenhouse gas mitigation option.     

Characterization of As and trace metals embedded in PM10 particles in Puebla City, México

Forty-eight air-filter samples (PM₁₀) were analysed to identify the concentration level of partially leached metals (PLMs; As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and V) from Puebla City, México. Samples were collected during 2008 from four monitoring sites: (1) Tecnológico (TEC), (2) Ninfas (NIN), (3) Hermanos Serdán (HS) and (4) Agua Santa (AS). The results indicate that in TEC, As (avg. 424 ng m^?3), V (avg. 19.2 ng m^?3), Fe (avg. 1,202 ng m^?3), Cu (avg. 86.6 ng m^?3), Cr (41.9 ng m^?3) and Ni (18.6 ng m^?3) are on the higher side than other populated regions around the world. The enrichment of PLMs is due to the industrial complexes generating huge dust particles involving various operations. The results are supported by the correlation of metals (Mn, Cd and Co) with Fe indicating its anthropogenic origin and likewise, As with Cd, Co, Fe, Mn, Pb and V. The separate cluster of As, Fe and Mn clearly signifies that it is due to continuous eruption of fumaroles from the active volcano Popocatépetl in the region.     

Representation of complex visual stimuli in the brain

A method was developed to investigate transfer properties of neurons in the visual system using pictures of complex visual stimuli. The picture is moved over the receptive field of a neuron so that it can scan it along programmed lines. The activity of the neuron during the scanning procedure is presented in a two-dimensional dot display on scale with the original picture. By superposition of the stimulus and the transfer pattern, one can find out to which detail of a stimulus the neuron responds. Neurons in the first intracerebral relay of the visual system, the lateral geniculate body, reduce a complex stimulus, such as a photograph of a natural environment, to its contours. Cortical cells only respond to contours either of a limited or of a wider range of orientations (simple and complex cells, respectively). But the course of contours is only described by a continuous representation of these contours in the cortical map of the visual field. This is done by the simple cells, which have small receptive fields and thus a higher resolving power, whereas complex cells with their large receptive fields monitor the approximate location of a moving stimulus. The function of these two classes of neurons is discussed in terms of visual behavior, i.e., for fixation, hold, and binocular vergence movements (simple cells), and for detection of moving objects and motor command signals towards these objects (complex cells). These functions are an important condition for foveal vision which is the basis of perception in primates. An important function of orientation sensitivity of simple cells may be the binocular alignment of contours in binocular fusion and stereoscopic vision.     

Reinforcement of Yeast Biomass Films with Bacterial Cellulose and Rice Husk Cellulose Nanofibres

Journal of Polymers and the Environment - In the last decades, cellulose nanoparticles have been widely used to reinforce polymeric materials due to their strength and their wide availability in...     

Validating an evidence-based, self-rated fall risk questionnaire (FRQ) for older adults

Background

Falls are a common, serious, and often unrecognized problem facing older adults. The objective of this study was to provide an initial clinical and statistical validation for a public health strategy of fall risk self-assessment by older adults using a Fall Risk Questionnaire (FRQ).

Methods

Adults age 65 + (n = 40) were recruited at a Los Angeles Veterans Affairs (VA) medical facility and at a local assisted living facility. Participants completed the FRQ self-assessment and results were compared to a “gold standard” of a clinical evaluation of risks using the American/British Geriatrics Society guidelines to assess independent predictors of falls: history of previous falls, fear of falling, gait/balance, muscle weakness, incontinence, sensation and proprioception, depression, vision, and medications. For the comparison, we used an iterative statistical approach, weighing items based on relative risk.

Results

There was strong agreement between the FRQ and clinical evaluation (kappa = .875, p < .0001). Individual item kappa values ranged from .305-.832. After dropping one FRQ item (vision risk) because of inadequate agreement with the clinical evaluation (kappa = .139, p = .321), the final FRQ had good concurrent validity.

Conclusions

The FRQ goes beyond existing screening tools in that it is based on both evidence and clinical acceptability and has been initially validated with clinical examination data. A larger validation with longitudinal follow-up should determine the actual strength of the FRQ in predicting future falls.     

Persistent organic pollutant patterns in grey seals (Halichoerus grypus)

The aim of this paper is to examine the patterns of polychlorinated biphenyls (PCB) in the grey seals (Halichoerus grypus) from the Baltic, Northeast and Eastern England, and the St. Lawrence Estuary (Canada). In fact, the feeding habits of the ringed seal (Phoca hispida) include ingestion of major quantities of benthic crustaceans that might cause observed differences obtained in PCBs, whereas the grey seal feed mainly on fish. The profile (percent in mixture) of polychlorinated biphenyls (PCB) 101, 118, 138, 153, and 180, and the total of their concentrations in mg/kg lipid in grey seals from the Baltic, from Northeast and Eastern England, and from the St. Lawrence estuary (Canada), were examined by principal component analysis (PCA). When considering the possible effects of consuming seafood by the grey seal, it is necessary to characterize populations and individuals according to the amounts they consume, since populations in different parts of the world are likely to show big differences in their consumption of seafood. The patterns differ between juveniles and adult animals, but the gender of adults and geography do not appear to play a role.     

Temporal variation in size-assortative mating and male mate choice in a spider with amphisexual care

Males should be more selective when they have a high investment in reproduction, especially in species with biparental or paternal care. In this context, male mate choice can promote size-assortative mating (SAM) when (1) large males win intrasexual disputes, (2) large females are more fecund, and (3) males prefer larger females to smaller ones. In the spider Manogea porracea, males exhibit high reproductive investment by building their webs above those of females and exhibiting extended care of offspring in the absence of females. Under these circumstances, we expect the occurrence of SAM and male preference for large females. Herein, we performed observations and experiments in the field to evaluate the hypotheses that (1) M. porracea mates assortatively by size and (2) SAM is influenced by male mate choice. Furthermore, we measured variables that could affect mating patterns, the sex ratios, and densities of both sexes. Pairing in M. porracea was positively size-assortative in 2012, but not in 2013. Large males won most disputes for mates and preferred larger females, which produced more eggs. The inconsistency in detection of SAM was due to population dynamics, namely variations in sex ratio and population density across the breeding season. Furthermore, we found that the significance of male mate choice on sexual selection of body size in M. porracea strongly depends on the competition intensity for mating opportunities. The traditional sexual selection hypothesis of SAM needs to be reviewed and must include measures of competition intensity.