Teori møter praksis – er miljøriktige bygg økonomisk gjennomførbare? Scenarioanalyse av konstruksjonsvalg på Ydalir

Teori møter praksis – er miljøriktige bygg økonomisk gjennomførbare? Hovedutfordringen for ZEN pilotområdet Ydalir er å sikre en riktig tilnærming til målet om reduksjon av klimagassutslipp slik at de totalt sett oppnår en balanse mellom samfunnshensyn, miljø og økonomi, for både utbygger og bruker. Denne rapporten ser nærmere på disse parameterne og ser på hvor mye f.eks. isolasjonstykkelse kan reduseres for å optimere samspillet mellom kostnader og klimagassutslipp fra energibruk og materialer. Dette gjøres ved å beregne energibehov, klimagassberegninger og livssykluskostnader for bygg 7 og 8 på Ydalir Torg i to scenarioer; et scenario som oppfyller byggteknisk forskrift (TEK17) og et scenario som oppfyller passivhus standarden. Energiresultater viser ca. 23% reduksjon i spesifikt energibehov og 30 -32% reduksjon i spesifikk levert energi mellom TEK17- og passivhus-scenarioene. Klimagassresultater viser at bygg 7 har lavere totale klimagassutslipp enn bygg 8 i begge scenarioene, på grunn av solcellene på taket til bygg 8. Selv om TEK17-scenarioet har høyere totale klimagassutslipp sammenlignet med passivhus-scenarioet er de totale klimagassutslippene fortsatt lavere enn grenseverdiene i de ulike programmene. Kostnads-resultater viser at passivhus-scenarioet er ca. 300 000 – 367 000 kr eller 3 – 5% dyrere enn TEK17-scenarioet for utbyggeren, mens energikostnadene viser en sparing på mellom ca. 5 700 – 6 000 kr hvert år i passivhus-scenarioet. Resultatene er nyttige fordi det viser at entreprenøren kan oppnå klimagasskravene sett i Ydalirs Masterplan ved å bygge TEK17-scenarioet og samtidig sparer på investeringskostnadene. Dette vil føre til rimelige boenheter på markedet som gjøre det lettere for kjøpere å skaffe seg bolig i et ZEN pilotområde. Resultatene kan anvendes til videreutvikling av ZEN definisjon og nøkkelindikatorer (KPI) samt i implementering av Ydalirs Masterplan. Studien har involvert Elverum Vekst, Nordbolig, Norlys Arkitektur, Multiconsult, SINTEF og NTNU. Resultatene har en praktisk tilnærming og viser at Nordboligs standardløsning (TEK17-scenarioet) kan iverksettes for å oppnå klimagasskravene i Ydalirs Masterplan. I konklusjon bidrar denne rapporten til videreutvikling og uttesting av ZEN definisjon og KPI på energi, klimagasser og økonomi og gir viktige innspill på metodiske valg, systemgrenser, og datagrunnlag for utvikling av referanseverdier.publishedVersio

Modeling venous bias in resting state functional MRI metrics

Resting-state (rs) functional magnetic resonance imaging (fMRI) is used to detect low-frequency fluctuations in the blood oxygen-level dependent (BOLD) signal across brain regions. Correlations between temporal BOLD signal fluctuations are commonly used to infer functional connectivity. However, because BOLD is based on the dilution of deoxyhemoglobin, it is sensitive to veins of all sizes, and its amplitude is biased by draining veins. These biases affect local BOLD signal location and amplitude, and may also influence BOLD-derived connectivity measures, but the magnitude of this venous bias and its relation to vein size and proximity is unknown. Here, veins were identified using high-resolution quantitative susceptibility maps and utilized in a biophysical model to investigate systematic venous biases on common local rsfMRI-derived measures. Specifically, we studied the impact of vein diameter and distance to veins on the amplitude of low-frequency fluctuations (ALFF), fractional ALFF (fALFF), Hurst exponent (HE), regional homogeneity (ReHo), and eigenvector centrality values in the grey matter. Values were higher across all distances in smaller veins, and decreased with increasing vein diameter. Additionally, rsfMRI values associated with larger veins decrease with increasing distance from the veins. ALFF and ReHo were the most biased by veins, while HE and fALFF exhibited the smallest bias. Across all metrics, the amplitude of the bias was limited in voxel-wise data, confirming that venous structure is not the dominant source of contrast in these rsfMRI metrics. Finally, the models presented can be used to correct this venous bias in rsfMRI metrics

Disruption of the sodium-dependent citrate transporter SLC13A5 in mice causes alterations in brain citrate levels and neuronal network excitability in the hippocampus

In addition to tissues such as liver, the plasma membrane sodium-dependent citrate transporter, NaCT (SLC13A5), is highly expressed in brain neurons, but its function is not understood. Loss-of-function mutations in the human SLC13A5 gene have been associated with severe neonatal encephalopathy and pharmacoresistant seizures. The molecular mechanisms of these neurological alterations are not clear. We performed a detailed examination of a Slc13a5 deletion mouse model including video-EEG monitoring, behavioral tests, and electrophysiologic, proteomic, and metabolomic analyses of brain and cerebrospinal fluid. The experiments revealed an increased propensity for epileptic seizures, proepileptogenic neuronal excitability changes in the hippocampus, and significant citrate alterations in the CSF and brain tissue of Slc13a5 deficient mice, which may underlie the neurological abnormalities. These data demonstrate that SLC13A5 is involved in brain citrate regulation and suggest that abnormalities in this regulation can induce seizures. The present study is the first to (i) establish the Slc13a5-knockout mouse model as a helpful tool to study the neuronal functions of NaCT and characterize the molecular mechanisms by which functional deficiency of this citrate transporter causes epilepsy and impairs neuronal function; (ii) evaluate all hypotheses that have previously been suggested on theoretical grounds to explain the neurological phenotype of SLC13A5 mutations; and (iii) indicate that alterations in brain citrate levels result in neuronal network excitability and increased seizure propensity

Motor sequences; separating the sequence from the motor. A longitudinal rsfMRI study

In motor learning, sequence specificity, i.e. the learning of specific sequential associations, has predominantly been studied using task-based fMRI paradigms. However, offline changes in resting state functional connectivity after sequence-specific motor learning are less well understood. Previous research has established that plastic changes following motor learning can be divided into stages including fast learning, slow learning and retention. A description of how resting state functional connectivity after sequence-specific motor sequence learning (MSL) develops across these stages is missing. This study aimed to identify plastic alterations in whole-brain functional connectivity after learning a complex motor sequence by contrasting an active group who learned a complex sequence with a control group who performed a control task matched for motor execution. Resting state fMRI and behavioural performance were collected in both groups over the course of 5 consecutive training days and at follow-up after 12 days to encompass fast learning, slow learning, overall learning and retention. Between-group interaction analyses showed sequence-specific decreases in functional connectivity during overall learning in the right supplementary motor area (SMA). We found that connectivity changes in a key region of the motor network, the superior parietal cortex (SPC) were not a result of sequence-specific learning but were instead linked to motor execution. Our study confirms the sequence-specific role of SMA that has previously been identified in online task-based learning studies, and extends it to resting state network changes after sequence-specific MSL