Enumerating Atlantic salmon smolt production in River Vindelälven based on habitat availability and parr densities : consequences of using different density estimation methods

Habitat mapping was conducted in the main stem of River Vindelälven in the autumn of 2009 along the salmon distribution area. The aim was to estimate the quantity of potential reproduction areas, including spawning and juvenile rearing habitats. The mapping included 61 km of various stream sections along the river length of 269 km. The total area of stream habitats was estimated to 647 ha of which 396 ha (61%) were considered as either potential or optimal juvenile nursery habitats. The area of these two habitat classes were used to estimate the smolt production in the river by using electro fishing densities of juveniles (0+ per 100 m2). Data from the years 2001-2005 was used in four methods to estimate smolt production for the years 2005-2006. Method 1 was based on average 0+ density multiplied with the area of juvenile habitats. Method 2 was based on reach specific 0+ densities multiplied with reach specific juvenile areas. Method 3 was based on reach specific 0+ densities adjusted for flow conditions multiplied with specific juvenile areas and Method 4 was based on Method 1 using various hypothetical juvenile densities. All methods estimated the total no of 0+ salmons on the available habitats and these were used in an age structured Leslie matrix model to estimate the smolt production. Method 1 differed significant from both Method 2 and Method 3 however; there was no significant difference between Method 2 and Method 3. The smolt production was estimated to c. 30 000-60 000 where Method 1 estimated the highest smolt run. By using ArcGIS analyses of field based habitat mapping results (c. 600 ha) Method 1 estimated c. 91 000-94 000 smolt.En biotopkartering av Vindelälvens huvudsakliga utbredningsområde för lax utfördes under hösten 2009. Syftet var att bestämma kvalitet och arealer på uppväxtområden för juvenila lax. Resultaten visade att Vindelälven har ca 61 km varierande strömsektioner (total längd ca 269 km). Den totala arealen av strömhabitat estimerades till 647 ha av vilka 396 ha gavs antingen goda, men inte optimala samt optimala uppväxtområden för lax. Dessa två klasser användes för att kunna estimera smoltproduktionen i älven. Elfisketätheter för 0+ lax (0+ per 100 m2) åren 2001-2005 användes i fyra olika metoder för att estimera smoltproduktionen 2005-2006. Metod 1 baserades på älvens medeltätheter av 0+ multiplicerat med arean av uppväxtområden. Metod 2 baserades på viktade tätheter av 0+ multiplicerat med platsspecifika arealer av uppväxtområden. Metod 3 baserades på viktade tätheter av 0+ korrelerat mot flödesvariationer multiplicerat med platsspecifika arealer av uppväxtområden och Metod 4 baserades på hypotetiska tätheter av 0+ med samma tillvägagångssätt som i Metod 1. Samtliga metoder användes för att estimera totala antalet 0+ lax på uppväxtområdena och dessa data användes i en åldersspecifik Leslie matrix modell för att skatta smoltproduktionen. Metod 1 skiljde sig signifikant mot både Metod 2 och Metod 3 men det var ingen signifikant skillnad mellan Metod 2 och Metod 3. Smoltproduktionen estimerades till ca 30.000-60.000 där Metod 1 skattade flest smolt. Vid skattningar med ArcGIS med grund från fältkarteringen (ca 600 ha) i kombination med Metod 1 estimerades smoltproduktionen till ca 91 000-94 000 smolt

An Effective Method to Estimate Composition Amplitude of Spinodal Decomposition for Atom Probe Tomography Validated by Phase Field Simulations

Reasonable evaluation of composition amplitude in spinodal decomposition is a challenge to microanalysis of atom probe tomography, especially at early stages when phase separation is not prominent. This impedes quantitative analysis of spinodal structure in atom probe tomography as well as comparison with simulated results from phase field simulations. We hereby report an effective method to estimate the composition amplitude by constructing an amplitude density spectrum. This method can sensitively determine the composition amplitude at early stages. In particular, it substantially bridges experimental and simulation techniques comprising both discrete and continuum data in the study of spinodal decomposition. Moreover, it was found that the commonly adopted Langer-Bar-on-Miller method for atom probe analysis underestimates the composition amplitude of spinodal decomposition. Case studies have been performed on the Fe-Cr binary alloys.Comment: 5 pages, 4 figure

Relationships between tree and soil properties in Picea abies and Pinus sylvestris forests in Sweden

The exchange of elements between plants and the soil in which they are growing creates reciprocal control of their element composition. Within plants, the growth rate hypothesis from ecological stoichiometry implies a strong coupling between C, N, and P. No similar theory exists for predicting relationships between elements in the soil or relationships between plants and the soil. We used a data set of element concentrations in needles and humus of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) forests in Sweden to investigate the extent to which relationships between elements (C, N, P, S, K, Ca, Mg, Fe, Mn, Al) can be observed within and between plants and soils. We found element composition to be more strongly controlled in needles than in humus. Elements that are covalently bound were also more strongly controlled, with no apparent differences between macro- and micronutrients. With the exception of N/C, there were surprisingly few relationships between elements in needles and humus. We found no major differences between the two tree species studied, but investigations of additional forest types are needed for firm conclusions. More control over element composition was exercised with respect to N than C, particularly in needles, so it might be advantageous to express nutrient concentrations relative to N rather than on a dry weight or carbon basis. Variations in many ecosystem variables appeared to lack ecological significance and thus an important task is to identify the meaningful predictors

Landau-like states in neutral particles

We show the emergence of a new type of dispersion relation for neutral atoms with an interesting similarity with the spectrum of 2-dimensional electrons in an applied perpendicular constant magnetic field. These neutral atoms can be confined in toroidal optical traps and give quasi Landau spectra. In strong contrast to the equi-distant infinitely degenerate Landau levels for charged particles, the spectral gap for such 2-dimensional neutral particles increases in particular electric field configurations. The idea in the paper is motivated by the development in cold atom experiments and builds on the seminal paper of Aharonov and Casher.Comment: 4 pages, 2 figure

Using a Discontinuous Grant to Identify the Effect of Grants on Local Taxes and Spending

When investigating the effects of federal grants on the behavior of lower-level governments, it is hard to defend the handling of grants as an exogenous factor affecting local governments; federal governments often set grants based on characteristics and performance of local governments. In this paper we make use of a discontinuity in the Swedish grant system in order to estimate the causal effects of general intergovernmental grants on local spending and local tax rates. The formula for the distribution of funds is used as an exclusion restriction in an IV-estimation. We find evidence of crowding-in, where federal grants are shifted to more local spending, but not to reduced local tax rates. Our results thus confirm a flypaper effect for Sweden.fiscal federalism, grants, flypaper effect, local taxation, local government expenditure, causal effects

Using a discontinuous grant rule to identify the effect of grants on local taxes and spending

When investigating the effects of federal grants on the behavior of lower-level governments, it is hard to defend the handling of grants as an exogenous factor affecting local governments; federal governments often set grants based on characteristics and performance of local governments. In this paper we make use of a discontinuity in the Swedish grant system in order to estimate the causal effects of general intergovernmental grants on local spending and local tax rates. The formula for the distribution of funds is used as an exclusion restriction in an IV-estimation. We find evidence of crowding-in, where federal grants are shifted to more local spending, but not to reduced local tax rates. Our results thus confirm a flypaper effect for Sweden.Fiscal federalism, grants, flypaper effect, local taxation, local government expenditure, causal effects

The Hamiltonian view of social evolution

Hamilton’s Rule, named after the evolutionary biologist Bill Hamilton, and the related concepts of inclusive fitness and kin selection, have been the bedrock of the study of social evolution for the past half century. In ’The Philosophy of Social Evolution’ (Oxford University Press, 2017), Jonathan Birch provides a comprehensive introduction to the conceptual foundations of the Hamiltonian view of social evolution, and a passionate defence of its enduring value in face of the recent high profile criticism. In this review essay, I first outline the version of Hamilton’s Rule defended by Birch, dubbed Hamilton’s Rule General, and its derivation. With this in place, I then navigate through the fierce disagreements that Hamilton’s Rule generates among social evolution researchers and evaluate Birch’s central argument of the book that HRG serves as an organizing framework for social evolution research under which we can compare and interpret more detailed causal models. I then spend the remainder of the review discussing what I take to be three of the most exciting implications of Hamilton’s thinking raised by Birch: (1) the extension of Hamilton’s Rule to mobile genetic elements, (2) maximization of inclusive fitness models and the idea of adaptation as organism design, and (3) the relationship between Hamilton’s approaches to social behaviour and the gene’s-eye view of evolution

The Case Against Commodity Agreements

Depth sensing nano-indentation investigations have been performed to determine the radial dependence of the hardness through the cross section of a Fe-based bulk glassy rod. We have found the hardness of the material decreases along radius from the center to the outermost surface. This phenomenon is attributed to the ‘cooling rate induced surface softening’.  Furthermore, a significant change (~15 %) in elastic modulus is noticed along the radius as well. QC 20120906Hero-

Surface polaritons in two-dimensional left-handed photonic crystals

Using an extended plane-wave-based transfer-matrix method, the photonic band structures and the corresponding transmission spectrum of a two-dimensional left-handed photonic crystal are calculated. Comparisons between the periodic structure with a single left-handed cylindric rod are made, and many interesting similarities are found. It is shown that, due to the localized surface polaritons presented by an isolated left-handed rod, there exist many exciting physical phenomena in high-dimensional left-handed photonic crystals. As direct results of coupling of the localized surface polaritons of neighboring left-handed rod, a lot of almost dispersionless bands, anti-crossing behavior, and a zero $\bar{n}$ gap are exhibited in the left-handed periodic structure. Moreover, in a certain frequency region, except distorted by a lot of anti-crossing behavior, there exists a continual dispersion relation, which can be explained by the long-wavelength approximation. It is also pointed out that high-dimensional left-handed photonic crystals can be used to design narrow-band filter.Comment: sign errors in equation

Efficient structural symmetry breaking for constraint satisfaction problems

Symmetry breaking for constraint satisfaction problems (CSPs) has attracted considerable attention in recent years. Various general schemes have been proposed to eliminate symmetries. In general, these schemes may take exponential space or time to eliminate all the symmetries. We identify several classes of CSPs that encompass many practical problems and for which symmetry breaking for various forms of value and variable interchangeability is tractable using dedicated search procedures or symmetry-breaking constraints that allow nogoods and their symmetrically equivalent solutions to be stored and checked efficiently