Vätterns pelagiska fiskbestånd

För 2010 noterades i stort sett samma fisktätheter i Vättern som för 2009, vilket var en nedgång jämfört med 2008. Skillnaden var framför allt en stark rekrytering av nors under 2008. Fisktätheten var fortfarande relativt hög och över medelvärdet för undersökningsperioden (1992-2010). Nors har haft en regelbunden och god årlig rekrytering under lång tid och utgjorde 2010 80 % av det totala antalet fiskar i pelagialen (den fria vattenmassan). Efter uppgången i norsbeståndet 2007 och den starka rekryteringen 2008 minskade mängden nors under 2009-2010, men tätheten av nors var fortfarande över medel för undersökningsperioden. Siklöjebeståndet gick i motsatt riktning. Åren 2008 och 2010 noterades det lägsta antalet siklöjor sedan undersökningarna startade 1988. Dessa två år fångades endast vuxna individer. År 2009 noterades något fler individer och då i stort sett bara från den norra delen av Vättern. Av siklöjorna från 2009 var ca 80 % ensomriga vilket visade att det fortfarande sker rekrytering till det svaga beståndet. Åldersläsning av siklöjor från Vättern 1992-2010 har visat att tillväxten är svag i flera år efter en stark årsklass och att återhämtningen efter lek hos de vuxna individerna tar flera år. Fiskbiomassan i pelagialen för hela Vättern beräknades 2010 till i genomsnitt 6,3 kg/ha (1 hektar = 100 x 100 m) vilket var något mindre än tidigare år. Fördelningen över sjön var jämnare 2010. Situationen för siklöjebeståndet i Vättern fortsätter att oroa. Olika orsaker kan enskilt eller i kombination förklara minskande bestånd och utebliven stark rekrytering. I Fiskeriverkets Resurs- och miljööversikt 2011 ges som biologiskt råd att fiske efter siklöja bör upphöra helt till dess beståndet återhämtar sig och att nuvarande tidsbegränsning av fisket borde omfatta hela Vättern istället för att vara geografiskt begränsad till den södra delen av sjön

Elevers behov av stöd i matematik : Några lärares upplevelser

Syftet med denna studie var att undersöka och analysera några lärares uppfattningar av hur de hanterar elevers behov av stöd i sin matematikundervisning. Det som denna kvalitativa fallstudie strävade efter att synliggöra, var dels lärarnas perspektiv på matematiksvårigheter, dels lärarnas hantering av elevernas behov av stöd i sin undervisning och deras beskrivning av orsakerna till de uppkomna behoven. Undersökningsgruppen bestod av matematiklärare åk 1-6 från tre olika kommuner. Studiens datainsamlingsmetoder utgjordes av dels fokusgruppssamtal dels samtal kring kritiska händelser. Insamlade data tolkades utifrån en hermeneutisk metodansats. Studien utgår från flera olika teoribildningar så som sociokulturell teori, Bronfenbrenners ekologiska systemteori samt Piagets kognitiva teori, då samtliga teorier synliggör den didaktiska aspekten av lärares handlingar. Resultatet visade att matematiksvårigheter upplevdes vara svårdefinierbart samt att kunskap inom området saknades bland flera av lärarna i studien. Förklaringar till svårigheter förlades främst på individnivå där språkliga svårigheter, elevers självbild samt svårigheter ej kopplade till matematiksvårigheter poängterades. Även undervisningsmiljö samt faktorer på samhällsnivå betraktades som hinder i lärandet. Stödet beskrevs i termer av kommunikativa stöttor, konkret material, men beskrevs också utifrån organisatoriska lösningar. I diskussionen diskuterades även kategoriska och relationella perspektiv samt dilemmaperspektiv som framträdde i lärarnas beskrivningar

Calibration of alanine dosimeters

In all kinds of radiation therapy it is of crucial importance to thoroughly determine the absorbed dose in the tumour, in surrounding normal tissue and in risk organs. This is done using various types of dosimeters, all with their advantages and disadvantages for different situations. Measurements of the dose distribution in a volume in terms of absolute absorbed dose are needed, for example to verify Monte Carlo calculations or clinical dose plans experimentally. To make such absolute dose measurements possible, the dosimeter requires calibration towards a dosimeter with a calibration factor that is traceable to a primary standard dosimetry laboratory. To not put the outcome of a radiation treatment at risk, the uncertainty in the absorbed dose determination at points of interest must not be higher than 5% (1 standard deviation) according to the ICRU (1976). The aim of this report is to indicate a way of calibrating two types of L-a-alanine dosimeters, an alanine/agarose gel and thin alanine films. The influence of some factors on the ESR signal from the alanine dosimeters is investigated, and suggestions are made on how to take these factors into account

Calibration of alanine dosimeters

In all kinds of radiation therapy it is of crucial importance to thoroughly determine the absorbed dose in the tumour, in surrounding normal tissue and in risk organs. This is done using various types of dosimeters, all with their advantages and disadvantages for different situations. Measurements of the dose distribution in a volume in terms of absolute absorbed dose are needed, for example to verify Monte Carlo calculations or clinical dose plans experimentally. To make such absolute dose measurements possible, the dosimeter requires calibration towards a dosimeter with a calibration factor that is traceable to a primary standard dosimetry laboratory. To not put the outcome of a radiation treatment at risk, the uncertainty in the absorbed dose determination at points of interest must not be higher than 5% (1 standard deviation) according to the ICRU (1976). The aim of this report is to indicate a way of calibrating two types of L-a-alanine dosimeters, an alanine/agarose gel and thin alanine films. The influence of some factors on the ESR signal from the alanine dosimeters is investigated, and suggestions are made on how to take these factors into account

Survival at 19 years of age in a total population of children and young people with cerebral palsy. Developmental Medicine and Child Neurology 2011; 53:808–814 doi: 10.1111/j.1469-8749.2011.04027.x PMID: 21745199

AIM The aims were to investigate survival of children with cerebral palsy (CP) and to search for modifiable factors that influence survival in CP. METHOD The total population of children with CP in southern Sweden born between 1990 and 2005, and followed from 1994 to 2010 comprised 718 children. The study included 708 of these children (297 females, 411 males) participating in a secondary prevention programme. CP subtype, Gross Motor Function Classification System (GMFCS) levels, and comorbidities were described. Kaplan-Meier survival curves were plotted. The following factors were investigated using Cox regression analysis: GMFCS level (co-varies with overall health), size of health care catchment area, gastrostomy feeding, and sex. RESULTS The estimated survival at 19 years of age was 60% in children with the most severe gross motor limitations (GMFCS level V). Death occurred throughout childhood. All children at GMFCS level I or II, and 96% of the whole CP population, survived. The mortality risk in childhood CP was three times higher in catchment areas that covered small populations than in areas with a large population. Gastrostomy feeding was associated with a ninefold increased risk of dying, regardless of GMFCS level and catchment area. INTERPRETATION Fragile children with CP, as indicated by GMFCS level V and gastrostomy feeding, had the lowest chance of surviving childhood. Health care catchment area seemed to influence survival rate

Fish density and target strength distribution of single fish echoes in varying light conditions with single and split beam echosounding and trawling

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Synthesis of theoretical and empirical experineces from nutrient and cyprinid reductions in Lake Ringsjön

The reduction in external phosphorus load to Lake Ringsjön during the 1980s, did not result in improved water transparency during the following ten-year period. Furthermore, a fish-kill in the Eastern Basin of the lake, in addition to a cyprinid reduction programme (biomanipulation; 1988–1992), in contrast to theory, did not lead to any increase in zooplankton biomass or size. This absence of response in the pelagic food chain may have been attributed to the increase in abundance of YOY (0+) fish, following the fish reduction programme. Despite the lack of effect on zooplankton, there was a decrease in phytoplankton biomass, a change in species composition and an increase in water transparency following biomanipulation. In 1989, one year after the fish-kill in Eastern Basin, the Secchi depth (summer mean) increased from 60 cm to 110 cm. In the following years, water transparency increased further, despite an increase in phosphorus loading. An unexpected effect of the biomanipulation was an increase in benthic invertebrate and staging waterfowl abundances, which occurred 2–4 years after fish reduction. Hence, the response in the benthic community following biomanipulation was considerably stronger than in the pelagic community. A likely explanation is that reduction in abundance of the benthic feeding fish species bream (Abramis brama), strongly affected the benthic invertebrate fauna. In this paper, we present what we believe happened in Lake Ringsjön, and which processes are likely to have been important at various stages of the restoration process

Expression of genes involved in oxidative stress responses in airway epithelial cells of smokers with chronic obstructive pulmonary disease

RATIONALE: The molecular mechanisms involved in airway oxidative stress responses reported in healthy smokers and in those with chronic obstructive pulmonary disease (COPD) are poorly understood. OBJECTIVES: To assess the expression of genes involved in oxidative stress responses in the bronchial epithelium of smokers with or without COPD and in relation to disease severity. METHODS: Global gene expression was assessed in bronchial brushings in 38 subjects with COPD, 14 healthy nonsmokers, and 18 healthy smokers. RESULTS: Gene expression analysis using Affymetrix arrays revealed mRNAs representing 341 out of 642 oxidative stress genes from two predefined gene sets to be differentially expressed in healthy nonsmokers when compared with healthy smokers, and 200 differentially expressed oxidative genes in subjects with COPD when compared with healthy smokers. Gene set enrichment analysis showed that pathways involved in oxidant/antioxidant responses were among the most differentially expressed gene pathways in smoking individuals, with further differences seen in COPD. Distinct, nonlinear gene expression patterns were identified across the severity spectrum of COPD, which correlated with the presence of certain transcription factor binding sites in their promoters. Significant changes in oxidant response genes observed in vivo were reproduced in vitro using primary bronchial epithelial cells from the same donors cultured at an air-liquid interface and exposed to cigarette smoke extract. CONCLUSIONS: Cigarette smoke induces significant changes in oxidant defense responses; some of these are further amplified, but not in a linear fashion, in individuals who develop COPD