Vole spatial distribution and dispersal in European organic and conventional farming systems

North European landscapes are highly dominated by agriculture, where small biotopes, e.g. meadows, uncultivated grassland, hedge rows, field boundaries, surroundings of water ponds, only comprise a low percentage. In recent years organic farming has expanded in acreage due to customers increased awareness regarding pesticide and fertilizer use and biodiversity conservation. However, organic farming has changed from an extensive production with small fields, low mechanical impact and high crop diversity towards larger fields, intensive mechanical treatment, lower weed densities and lower field diversity. Still, organic farms could play an important, role in the agricultural landscape as refuges for some small mammal species. We studied the responses of populations to habitat patches of different size and different surrounding management strategies (ecological and conventional farming). Studies were performed at two localities in Denmark, Kalø Estate in Eastern Jutland and the Bjerringbro area in Central Jutland. The sampling sites were represented by cultivated grassland habitat, small biotopes within cultivated fields and hedgerows between fields in rotation. Small mammal species assemblages were low in numbers in cultural farmland, and, on a property basis, not significantly different between organic and conventional farms. Very few species and individuals were present in the field matrix, and the small biotopes were by far the most important source of species richness. Species density was positively correlated with the size of the habitat, and, generally, more voles were found in organic habitat patches than in conventional ones. More field voles were found in organic grassland and more bank voles (Myodes glareolus) in organic hedge rows than in conventional ones. Telemetry studies of field voles showed low rates of dispersal and low colonization rates of the more or less isolated small biotopes at the time of year with no vegetation cover in the surrounding fields. We found no significant correlations between distance to nearest stepping stones/dispersal corridors and small mammal densities or species composition. In agricultural areas landscape structure influences the small mammal species living in this fragmented habitat matrix. The value of organic farms in respect to small mammal biodiversity depends mainly upon the number and area of small biotopes, and only to a minor degree upon the management of the fields. This is presumably related to a more dense and diverse vegetation cover, due to a lack of pesticide and fertilizer treatment in the organically managed small biotopes

Identification Theory for Time Varying Models

The identification of time-varying coefficient regression models is investigated using an analysis of the classical information matrix. The variable coefficients are characterized by autoregressive stochastic processes, allowing the entire model to be case in state space form. Thus the unknown stochastic specification parameters and priors can be interpreted in terms of the coefficient matrices and initial state vector. Concentration of the likelihood function on these quantities allows the identification of each to be considered separately. Suitable restriction of the form of the state space model, coupled with the concept of controllability, lead to sufficient conditions for the identification of the coefficient transition parameters. Partial identification of the variance-covariance matrix for the random disturbances on the coefficients is established in a like manner. Introducing the additional concept of observability then provides for necessary and sufficient conditions for identification of the unknown priors. The results so obtained are completely analogous to those already established in the econometric literature, namely, that the coefficients of the reduced form are always identified subject to the absence of multicollinearity. Some consistency results are also presented which derive from the above approach.

On the Identification of Time Varying Structures

The identifiability of reduced form econometric models with variable coefficients is investigated using the control theoretic concepts of uniform complete observability and uniform complete controllability. First, a variant of the state space representation of the traditional reduced form is introduced which transcribes the underlying non-stationary estimation problem into one particularly suited to a Kalman filtering solution. Using such a formulation, observability and controllability can be called upon to obtain a necessary and sufficient condition for identification of the specific parameterization. The results so obtained are completely analogous to those already established in the econometric literature, namely, that the parameters of the reduced form are always identified subject to the absence of multicollinearity(referred to as "persistent excitation" in the control literature). How-ever, now the multicollinearity condition is seen to depend on the structure of the parameter variations as well as the statistical nature of the explanatory variables. The verification of identifiability thus reduces to a check for uniform complete observability which can always be affected in econometric applications. Some consistency results are also presented which derive from the above approach.

ORGANIC FARMS AS REFUGES FOR SMALL MAMMAL BIODIVERSITY

Habitat fragmentation, the process by which relatively continuous habitats is broken into smaller pieces, occurs in natural systems but is to a high degree also human- induced through landscape use. Fragmentation of the landscape produces a series of habitat patches surrounded by a matrix of different habitats and/or land use regimes. The major landscape consequences of fragmentation are loss of habitat, reduction in habitat patch size, and increasing isolation of habitat patches. In general, population performance declines in response to habitat loss but size of remaining area and isolation effects is known also to influence the population trend. Small mammals are well suited for examination of population responses to habitat fragmentation as they have modest spatial requirements and short generation times. In theory, organic farms could play an important role in the agricultural landscape as refuges for some small mammal species, as the lack of pesticide and fertiliser treatment, less weed control, more diversified crop structure and a general environmentalfriendly attitude, form a basis for habitats that provide cover and food for small mammals, and thus for larger predators of these species. Furthermore, density and area of small biotopes could be expected to be higher in the organic farms, thus leading to a decreased distance between optimal habitats

Organic farms as refuges for small mammal biodiversity in agro ecosystems

Habitat fragmentation, the process by which relatively continuous habitats is broken into smaller pieces, occurs in natural systems but is to a high degree also human-induced through landscape use. Fragmentation of the landscape produces a series of habitat patches surrounded by a matrix of different habitats and land use regimes. The major landscape consequences of fragmentation are loss of habitat, reduction in habitat patch size, and increasing isolation of habitat patches. In general, population performance declines in response to habitat loss but size of remaining area and isolation effects is known also to influence the population trend. Small mammals are well suited for examination of population responses to habitat fragmentation as they have modest spatial requirements and short generation times. In theory, organic farms could play an important role in the agricultural landscape as refuges for some small mammal species, as the lack of pesticide and fertiliser treatment, less weed control, more diversified crop structure and a general environmental friendly attitude, form a basis for habitats that provide cover and food for small mammals, and thus for larger predators of these species. Furthermore, density and area of small biotopes could be expected to be higher in the organic farms, thus leading to a decreased distance between optimal habitats. This study compares species diversity and abundance of small mammals in conventional farms and intensively and extensively grown organic farms. In a wide range of different fields in conventional and organic farms, the diversity and density of small mammals were investigated by live-trapping sessions, comprising trap lines with 15 meters between each trap. We studied the responses of populations (belonging to 11 species of small mammals) to habitat patches of different size and different surrounding management strategies (ecological and conventional farming). We found a general correlation between the number of small mammal individuals and small biotope size. This correlation applies in autumn as well as in spring. There is only a weak tendency for more small mammals in small biotopes within organic farms compared within conventional farms. The number of small mammal species stabilises at small biotope sizes around 1000 square meters. The value of organic farms in respect to small mammal biodiversity depends mainly upon the number and area of small biotopes, and only to a minor degree upon the treatments of the fields

A Note on Optimal Smoothing for Time Varying Coefficient Problems

An algorithm is presented which provides a complete solution to the optimal estimation problem for time-varying parameters when no proper prior distribution is specified. The key ideas involve a combination of the information-form Kalman filter with the two-filter interpretation of the optimal smoother. The algorithm produces efficient estimates of the parameter trajectories over the entire sample, arid is equally applicable when a proper prior distribution has been specified.

XSIL: Extensible Scientific Interchange Language

We motivate and define the XSIL language as a flexible, hierarchical, extensible transport language for scientific data objects. The entire object may be represented in the file, or there may be metadata in the XSIL file, with a powerful, fault-tolerant linking mechanism to external data. The language is based on XML, and is designed not only for parsing and processing by machines, but also for presentation to humans through web browsers and web-database technology. There is a natural mapping between the elements of the XSIL language and the object model into which they are translated by the parser. As well as common objects (Parameter, Array, Time, Table), we have extended XSIL to include the IGWDFrame, used by gravitational-wave observatories

New investigations into golden shiner culture

Survival of golden shiner Notemigonous crysoleucas larvae fed nine different formulated diets was evaluated in 2007 and 2008. Fry (1-d post hatch) were stocked equally into indoor tanks and then pair-wise comparisons were ran to evaluate differences in survival among different prepared foods in 14-d culture trials. In 2007 six diets were evaluated and in 2008 three more diets were evaluated against the best performing diet from the 2007 trials. Stocking rates ranged from 8-40 fry/L. In 2007, only the ZeiglerTM AP100 trial resulted in any survival of fry. That diet was then used in 2008 as the control for additional pair-wise comparisons. Results from the 2008 culture season showed ZeiglerTM AP100 again yielded the best survival; mean survival ranged from 1-28%, while the other three diets had mean survival that ranged from 4-6%. Results from this study show that more effort needs to be directed toward developing a more nutritionally complete diet for golden shiners. In addition, there is need to refine better culture techniques for growth and survival in indoor tank systems. Better feeds and improved culture methods are also needed to support the growth of the golden shiner industry in indoor systems. Organic fertilizer was compared to a mix of organic and inorganic fertilizers for the culture of golden shiners (Notemigonus crysoleucas) in 0.08-ha earthen culture ponds in 2007. Age-1 broodstock were stocked (51.6 kg/ha) on May 1, 2007 and all ponds were harvested October 29-November 1, 2007. Organic fertilization consisted of one application of soybean meal at a rate of 9.1 kg/pond/week followed by weekly applications at a rate of 4.5 kg/pond/week for 5 weeks. Nitrogen (36-0-0) fertilizer was used for 4 weeks to adjust nitrate-nitrogen to total phosphorus ratios (NO3-N:TP) to 7:1 on the mixed fertilizer treatment. Water temperature, DO, and pH were all within acceptable ranges for golden shiner pond culture. Nitrite levels were low in both treatments throughout the culture period. Ammonia-nitrogen (TAN) had the largest difference between treatments with the mixed fertilization treatment having elevated TAN levels compared to the organic fertilizer only treatment. Golden shiner fry collected at harvest in the organic only fertilization treatment averaged 71.2 mm + 8.8 in length while those harvested in the mixed fertilization treatment averaged 82.2 mm + 4.0. Golden shiner fry in the organic only treatment averaged 4.6 g + 2.6 in weight while the fry in the mixed fertilization treatment averaged 4.9 g + 0.8. Total production from this experiment was 537 kg/ha + 148.7 in the organic only treatment and 548 kg/ha + 63.5 in the mixed fertilization treatment; total age-0 golden shiner fry numbers harvested averaged 326,215/ha + 186192 in the organic only treatment and 115,972/ha + 20764 in the mixed fertilization treatment. The average length, weight, and production (weight and numbers/ha) were all found to be not significant (P\u3c0.1). Diet selection was evaluated by examination of contents of fish stomachs and Chydorus and cyclopoids were the preferred prey species in both treatments

Adult Scoliosis And Chronic Low Back Pain With Land And Aquatic Based Physical Therapy: A Case Report

Background and Purpose: Scoliosis is commonly an idiopathic condition that occurs in approximately 2-3% of the population and is defined by a lateral spinal curvature of greater than 10 degrees. Common symptoms associated with scoliosis include decreased pulmonary function and chronic spinal pain. Depending on the degree of curvature bracing or surgery may be required. The purpose of this case study is to evaluate the effects of an aquatic and land based exercise program on an adult with severe, untreated, early onset scoliosis. Case Description: The patient was a 55-year-old female with a history of scoliosis and recent onset of low back pain. The chief complaint was severe back pain, which limited her ability to function at her job and impaired her ability to sleep. X-ray results showed severe scoliosis in the lumbar spine with lateral subluxations at L3 on L4. The plan of care consisted of aquatic based therapy for lumbar stabilization and decompression and land based therapy for soft tissue manipulation and lumbar stabilization. Outcomes: Throughout this plan of care, the patient’s pain decreased from 4/10 to 0/10 at rest, 10/10 to 4/10 with prolonged activity, and 6/10 to 1-2/10 on average. The patient also demonstrated a significant change in Oswestry Disability Index score from 28% to 10%. Discussion: This case report suggested that aquatic and land based therapy that was focused on transverse abdominis activation for lumbar stabilization, spinal decompression, and soft tissue manipulation decreased our patient’s low back pain and improved her functional mobility as evident by improved pain scores and Oswestry Disability Index scores. Further research is suggested to assess the long-term effects of aquatic and land based intervention