Dimensionless invariants for the optimal size (age) of sex change

Optimization models have been widely and successfully used in evolutionary ecology to predict the attributes of organisms; perhaps the greatest quantitative success is in the area of sex allocation (sex ratio, sperm versus eggs for hermaphrodites, time as a male [female] for a sex changer), where the fact of having only one mother and one father makes Darwinian fitness a simple product of gain-via-male times gain-via-female. Previous work on sex change used the maximization of this male—female product to successfully predict the direction and age (size) for sex change, and that age has been shown to imply a breeding sex ratio biased towards the first sex. This paper unites recent advances in the comparative demography of organisms with indeterminant growth with the theory of optimal sex change to predict some new invariance rules for the relative age (size) of sex change. One of these rules is strikingly confirmed in a long term study of the size-at-sex-change in the northern shrimp, Pandalus borealis, off Iceland

MAP1B mutations cause intellectual disability and extensive white matter deficit

Publisher's version (útgefin grein). Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Discovery of coding variants in genes that confer risk of neurodevelopmental disorders is an important step towards understanding the pathophysiology of these disorders. Wholegenome sequencing of 31,463 Icelanders uncovers a frameshift variant (E712KfsTer10) in microtubule-associated protein 1B (MAP1B) that associates with ID/low IQ in a large pedigree (genome-wide corrected P = 0.022). Additional stop-gain variants in MAP1B (E1032Ter and R1664Ter) validate the association with ID and IQ. Carriers have 24% less white matter (WM) volume (β = −2.1SD, P = 5.1 × 10−8), 47% less corpus callosum (CC) volume (β = −2.4SD, P = 5.5 × 10−10) and lower brain-wide fractional anisotropy (P = 6.7 × 10−4). In summary, we show that loss of MAP1B function affects general cognitive ability through a profound, brain-wide WM deficit with likely disordered or compromised axons.We are grateful to the participants and we thank the psychologists, nurses and staff, in particular Berglind Eiriksdottir, at the Research Recruitment Center and technicians and staff at Röntgen Domus. We also thank the staff at deCODE genetics core facilities and all our colleagues for their important contribution to this work. L.J. received support from the Swedish Society of Medicine, the Swedish Brain Foundation and Swedish Society for Medical Research. The research leading to these results has received support from the Innovative Medicines Initiative Joint Undertaking under grant agreements’ no. 115008 (NEWMEDS) and no. 115300 (EUAIMS) of which resources are composed of EFPIA in-kind contribution and financial contribution from the European Union’s Seventh Framework Programme (EU-FP7/2007-2013), EU-FP7 funded grant no. 602450 (IMAGEMEND) and EU funded FP7-People-2011-IAPP grant agreement no. 286213 (PsychDPC).Peer Reviewe

Kostir útikennslu á yngsta stigi grunnskólans

Þessi ritgerð er lögð fram til B.Ed.-gráðu í grunnskólakennarafræði við Háskóla Íslands. Viðfangsefni hennar er útikennsla og markmiðið er að varpa ljósi á þá kosti sem hún hefur á yngsta stigi grunnskólans. Með útikennslu er átt við það þegar kennsla er færð út fyrir veggi skólans með nám að leiðarljósi og stuðlað er að því að nemendur læri með því að framkvæma og upplifa. Í ritgerðinni er fjallað um helstu kosti útikennslu og hvernig hún getur komið að gagni við nám en hún getur farið fram víða og þarf ekki að taka langan tíma. Fjallað er um mikilvægi hreyfingar og hvernig útikennsla stuðlar að aukinni hreyfingu og útivist. Komið er inn á áhrif útikennslu á Íslandi og sérstaklega hvernig náttúrufræði hefur verið nýtt sem grunnur að útikennslu. Gerð eru skil á kenningum fræðimannanna Jean Piaget, John Dewey, Lev Vygotsky og Howard Gardner og hvernig þær styðja útikennslu. Einnig verður vikið að hlutverki kennara sem er mjög mikilvægt enda að mörgu að huga. Að lokum er fjallað um námsmat sem er nauðsynlegur hluti af útikennslu og nokkur dæmi nefnd um æskilegt námsmat

Bottom Trawling and Scallop Dredging in the Arctic : Impacts of fishing on non-target species, vulnerable habitats and cultural heritage

This project has been developed within the frame of the Nordic Action Plan 2000-2004 (Nord 1999:29) to review the status and threats of the natural and cultural heritage in Arctic waters. Two of the most commonly used demersal fishing gears in the Arctic are the otter trawl and the scallop dredge. Detrimental effects of bottom gear towed over the seabed include incidental catch and direct mortality of a wide range of organisms and habitat alteration. Any three-dimensional fragile structures rising above the seabed, such as cold-water corals, sponges, geological formations and archaeological remains are easily destroyed. This report reviews the scallop and shrimp fisheries, the distribution and conservation of vulnerable habitats (coral reefs, sponge communities), the status of archaeological remains on the seabed and relevant legislation and the conservation measures and role of protected areas. In addition there are two case studies based on fisheries and survey data from Iceland and recommendations to improve the current situation

A PRPH splice-donor variant associates with reduced sural nerve amplitude and risk of peripheral neuropathy

Publisher's version (útgefin grein).Nerve conduction (NC) studies generate measures of peripheral nerve function that can reveal underlying pathology due to axonal loss, demyelination or both. We perform a genome-wide association study of sural NC amplitude and velocity in 7045 Icelanders and find a low-frequency splice-donor variant in PRPH (c.996+1G>A; MAF = 1.32%) associating with decreased NC amplitude but not velocity. PRPH encodes peripherin, an intermediate filament (IF) protein involved in cytoskeletal development and maintenance of neurons. Through RNA and protein studies, we show that the variant leads to loss-of-function (LoF), as when over-expressed in a cell line devoid of other IFs, it does not allow formation of the normal filamentous structure of peripherin, yielding instead punctate protein inclusions. Recall of carriers for neurological assessment confirms that from an early age, homozygotes have significantly lower sural NC amplitude than non-carriers and are at risk of a mild, early-onset, sensory-negative, axonal polyneuropathy.We thank all participants in deCODE studies for their valuable contribution to research, especially the participants of the deCODE Health Study and the deCODE Study on Genetics of Chronic and Neuropathic Pain. We also thank the research staff at the Patient Recruitment Center, and all colleagues who contributed to phenotype ascertainment, recruitment, collection of data, sample handling, and genotyping. The financial support from the European Commission to the NeuroPain project (FP7#HEALTH-2013-602891-2) and the National Institutes of Health (R01DE022905) is acknowledged.Peer Reviewe