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

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

Den ändliga vilan

Kyrkogården får en allt mer betydande roll i storstaden. Från att ha gått från enbart en plats för de döda hyser kyrkogården idag flera betydande funktioner. En av dessa är som grönt rum i staden dit människor söker sig för att ta del av lugnet och grönskan. Denna plats definieras av kulturella och sociala yttringar som styr vilka aktiviteter som här sker, vilket skapar förutsättningar för rekreation som inte är aktivitetsbaserad. Denna uppsatsens syfte är att undersöka vilka kvalitéer som finns på kyrkogården som främjar psykisk hälsa. Uppsatsen utgår från en litteraturstudie och fallstudie med platsbesök på S:t Pauli kyrkogårdar i Malmö. I litteraturstudien redogörs dels för den skandinaviska kyrkogårdens historia och nutida funktion, dels för miljöpsykologiska teorier på hur människan påverkas av gröna miljöer. För fallstudien har Patrick Grahns teori om de 8 parkkaraktärerna använts som underlag, dessa är Rofylldhet, Vildhet, Artrikedom, Rymd, Vidd/Allmänning, Refug/Viste, Samvaro/Möte och Kultur. Karaktärerna används som måttstockar på de kvalitéer som S:t Pauli kyrkogårdar har och används här för att dra generella slutsatser om den urbana kyrkogårdens hälsofrämjande kvalitéer. Studien visar att kyrkogårdar i större städer kan vara miljöer där karaktärerna rofylldhet, artrikedom och kultur får stor plats. Litteratur och fallstudie antyder att kyrkogården som plats har goda förutsättningar för att hysa kvalitéer som verkar för hälsofrämjande effekter. Fler undersökningar på ämnet behövs dock göras för att kunna dra generella slutsatser.The cemetery is given an increasingly important role in the urban environment. From being a place for the deceased, the cemetery now houses several significant functions. One of these is being an urban greenspace where people can find a calm and green environment. This place is defined by cultural and social norms that limits the activities performed here, which creates conditions for non-activity-based recreation. The purpose of this thesis is to investigate which qualities exists in the cemetery that promote mental health. This is done via a literature-study and a case study from S:t Pauli cemeteries in Malmö. In the literature study, both the history and present function of the Scandinavian cemetery are reported as well as environmental psychological studies of how man is affected by green environments. For the case study, I have used professor Patrik Grahns’s theory of the 8 park characters as a basis, these are Serene, Nature, Rich in Species, Space, Prospect, Refuge, Social and Culture. These characters are used as measurements for the qualities on S:t Pauli cemeteries and are used as a basis for general conclusions about qualities for mental health promotion of the urban cemetery. The study suggests that cemeteries in urban environments have an affinity for the characteristics Serene, Rich in Species and Culture. The case study and literature suggest that the urban Cemetery accommodates qualities that is beneficial for health promoting effects. However, more research on the subject is needed to draw more general conclusions

Electrophysiology-based investigations of G protein-coupled receptor pharmacology

G protein-coupled receptors (GPCRs) constitute targets for ~34% of approved drugs. The muscarinic acetylcholine M2 receptor (M2R) activates G protein-coupled receptor inward rectifying potassium (GIRK) channels in the central nervous system and heart. Membrane potential modulates agonist potency at several GPCRs. However, the mechanism underlying the voltage sensitivity remains debated. A highly conserved aspartate residue (D2.5069) has been proposed to mediate the voltage-sensitivity of the M2R, although the low expression of D69 mutants has complicated further functional investigations. Dopamine D2 and D3 receptors (D2R and D3R) are pre- and postsynaptic inhibitory receptors in the central nervous system, involved in locomotion, cognition and endocrine functions. D2R antagonists and weak partial agonists are used clinically as antipsychotics but are associated with several side effects. Various strategies have been suggested to reduce the side-effect profile of novel antipsychotic drugs. One such strategy includes the selective targeting of non-canonical signaling pathways, e.g., the β-arrestin pathway, while leaving the classical, G protein pathway, undisturbed. Additionally, binding affinity and kinetics at the D2R, as well as ligand lipophilicity, have been suggested to be of significance in determining the side-effect liability of antipsychotics. In the thesis, M2R, D2R and D3R were investigated using two-electrode voltage-clamp in Xenopus laevis oocytes co-expressing the respective receptor and GIRK channels. M2R carrying a charge-neutralizing D69N mutation demonstrated a voltage-dependent shift of agonist-potency, similar to the wild type M2R. This finding is in line with a recent alternative hypothesis, which implicates three tyrosine residues in the M2R voltage sensor. The proposed β-arrestin-selective partial D2R agonist, UNC9994, was found to be a weak partial- and almost full agonist at D2R and D3R mediated GIRK activation, respectively. These findings are incongruent with β-arrestin-selectivity and suggest that the promising effects of UNC9994 in animal models of psychosis may be related, at least in part, to involvement of the D3R. Finally, the partial D2R agonist positron emission tomography ligand, SV-III-130, demonstrated an insurmountable, yet competitive, binding mechanism at the D2R. Mutations of residues in a secondary binding pocket, engaging the secondary pharmacophore, abolished the insurmountable binding. Kinetic models incorporating an irreversible, SV-III-130-bound state captured the experimentally observed data. Molecular dynamics simulations suggested that D2R extracellular linkers participate in an induced-fit binding mechanism. In summary, the thesis addresses the mechanism of voltage-dependent agonist-potency at GPCRs and contradicts earlier reports of a β-arrestin-selective action of the experimental antipsychotic, UNC9994, at the D2R. Finally, a two-step induced-fit binding mechanism was demonstrated for the aripiprazole analogue, SV-III-130, at the D2R. The findings may guide further mechanistic investigations and provide insights for the development of novel diagnostic and therapeutic GPCR ligands

Review: Attachment Devices of Insect Cuticle

Gorb, S. 2001: Attachment Devices of Insect Cuticle. Kluwer Academic Publishers, Dordrecht/Boston/ London. 305 pages. ISBN 0-7923-7153-4

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

Tree origin or traits?

A global decline in diversity of plants and animals, has led to an increased focus on the topic of biodiversity. The trend of urbanisation can be a facilitator for biodiversity loss, and cities generally have lower densities of species compared to non-urban areas. This has made biodiversity in cities an important concept. Cities can support both people and biodiversity, but knowledge is required by the professions working with planning and managing urban parks and green spaces. Trees are a vital component of urban parks and green spaces and have great importance for biodiversity in cities. Knowledge of how plants and trees interact with other species is thus important when aiming to improve biodiversity, and some research on the subject suggests that native plants are better for biodiversity while other research claims the benefits of non-native plants in urban areas for both biodiversity and other ecosystem-services. Most trees, regardless of species, share similar characteristics such as bark, branches, flowers, and leaves that could be important habitats for insects, an invertebrate group that is a prerequisite for biodiversity on higher trophic levels. This thesis is a part of a longer research project from SLU regarding biodiversity in urban environments. The data collected is intended for further studies regarding biodiversity in urban trees and greenspaces. The research question for this thesis is: Does geographical origin or tree morphological traits affect a tree’s suitability to act as a host for local insect fauna? The aim is to gain an understanding of the complex interplay between species interactions regarding trees and insects. Such understanding could be used in different fields and disciplines for planning and maintaining a biodiversity-friendly urban forest. The main method has been a field collection of insects from trees in the central Malmö area with a supporting literature study of trees as insect habitats. The criteria for trees inventoried was: old age, geographical origin and presence in both park and street environments. This resulted in 42 trees evenly divided on 6 species, Acer platanoides, Acer pseudoplatanus, Acer tataricum subsp. ginnala, Crataegus monogyna, Crataegus intricata and Crataegus orientalis. The result from literature and field method indicated that insect abundance varies between native and non-native trees without any correlation regarding geographical origin or morphology. Crataegus monogyna had a significantly higher number of larvae than other Crataegus species and Acer pseudoplatanus had a higher number of aphids than other Acer species. According to literature and field observations, non-native trees have the same morphological prerequisites as native trees to act as habitat, which indicates that more factors than geographical origin or morphological components affects the insect abundance in a tree. These findings may give an insight into the understanding of trees as urban habitats. The information might prove useful to greenspace planners, managers, urban ecologists, and urban foresters working to improve biodiversity in cities

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