709 research outputs found
A linear auroral current-voltage relation in fluid theory
Progress in our understanding of auroral currents and auroral electron acceleration has for decades been hampered by an apparent incompatibility between kinetic and fluid models of the physics involved. A well established kinetic model predicts that steady upward field-aligned currents should be linearly related to the potential drop along the field line, but collisionless fluid models that reproduce this linear current-voltage relation have not been found. Using temperatures calculated from the kinetic model in the presence of an upward auroral current, we construct here approximants for the parallel and perpendicular temperatures. Although our model is rather simplified, we find that the fluid equations predict a realistic large-scale parallel electric field and a linear current-voltage relation when these approximants are employed as nonlocal equations of state. This suggests that the concepts we introduce can be applied to the development of accurate equations of state for fluid simulations of auroral flux tubes.<br><br><b>Key words.</b> Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions) â Space plasma physics (kinetic and MHD theory
Clinical and Biochemical Aspects of the Emergency Management of Traumatic Brain Injury
PopulĂ€rvetenskaplig sammanfattning(Summary in Swedish)HjĂ€rnskada som orsakas av olyckor Ă€r en vanlig orsak till bĂ„de handikapp och död bland vuxna. För 30 Ă„r sedan var majoriteten av de som drabbades yngre eller vĂ€ldigt gamla. Ă
lderssammansĂ€ttningen av de som drabbas har skiftat under de senaste 20 Ă„ren och nu Ă€r det ungefĂ€r lika vanligt i alla Ă„ldrar. Dessutom Ă€r den vanligaste olycksorsaken inte lĂ€ngre fordonsolyckor utan fall i samma plan.För lĂ€kare som handlĂ€gger skallskadade patienter pĂ„ akutmottagningar finns det flera olika riktlinjer. Dessa skiftar i olika lĂ€nder och kan vara utfĂ€rdade av enskilda forskargrupper eller nationella organ. De Ă€r ofta baserade pĂ„ forskning som Ă€r Ă€ldre Ă€n 15 Ă„r vilket kan medföra att de inte Ă€r helt aktuella.En riktlinje som ofta anvĂ€nds i Skandinavien rekommenderar att man mĂ€ter nivĂ„n av S100B i blodet pĂ„ vissa grupper av skallskadade patienter. Detta Ă€r en sĂ„ kallad biomarkör som kan hjĂ€lpa till att utesluta att patienten som drabbats av skallskadan har hjĂ€rnblödning. Det finns ett antal sĂ„dana biomarkörer men S100B Ă€r den enda som anvĂ€nds i klinisk praxis. Flera andra biomarkörer hĂ„ller pĂ„ att testas och nyligen har anvĂ€ndning av tvĂ„ andra biomarkörer godkĂ€nts för kliniskt bruk i USA.Det finns tvĂ„ sĂ€kra sĂ€tt att utesluta allvarlig hjĂ€rnblödning efter skallskada: observation pĂ„ sjukhus eller skiktröntgen av skallen. Fördelen med observation Ă€r att det inte innebĂ€r att patienten utsĂ€tts för strĂ„lning som kan vara skadlig och nackdelen Ă€r att man tar vĂ„rdresurser i ansprĂ„k. Skiktröntgen kan bĂ„de utesluta och pĂ„visa hjĂ€rnblödning med i det nĂ€rmaste fullstĂ€ndig sĂ€kerhet men krĂ€ver att man utsĂ€tter patienten för strĂ„lning.Riktlinjerna för handlĂ€ggning av skallskada har testats i flera vetenskapliga studier och det rĂ„der inga tvivel om att nĂ€r de följs förbĂ€ttrar de kvaliteten pĂ„ handlĂ€ggningen, dels genom att göra den mer konsekvent men ocksĂ„ genom att minska antalet skiktröntgenundersökningar och dĂ€rmed ocksĂ„ kostnaderna. Dock efterföljs inte alltid riktlinjer och trots omfattande forskning pĂ„ omrĂ„det har vi inget bra recept för att utveckla och införa en riktlinje sĂ„ att den efterlevs av majoriteten av de som den riktar sig till.För att kunna mĂ€ta S100B mĂ„ste man ta ett blodprov frĂ„n en ven och detta sker vanligtvis i armvecket. Att mĂ€ta det i ett blodprov som tas frĂ„n kapillĂ€ra blodkĂ€rl (genom ett stick i fingret) eller i urin som insamlas genom att patienten kissar i en11provburk skulle ha uppenbara fördelar men det finns inte tillrĂ€ckligt med kunskap om S100B i dessa kroppsvĂ€tskor för att det ska kunna rekommenderas.Denna avhandling baserar sig pĂ„ fem olika delarbeten som utforskar olika aspekter av handlĂ€ggning av patienter med skallskada och det övergripande syftet Ă€r att bidra med kunskap som ska kunna förbĂ€ttra omhĂ€ndertagande av skallskadade patienter pĂ„ akutmottagningar.Delarbete 1 genomfördes med frĂ„geformulĂ€r som delades ut till lĂ€kare pĂ„ en akutmottagning efter att de handlagt en patient med skallskada. Syftet var att kartlĂ€gga lĂ€karnas attityder till skiktröntgen av huvudet, att se hur vĂ€l de efterlevde riktlinjerna och hur införandet av nya riktlinjer pĂ„verkade anvĂ€ndning av riktlinjer. Det visade sig att lĂ€karna litade mer pĂ„ sitt eget omdöme Ă€n riktlinjerna men att de ofta bestĂ€llde skiktröntgen trots att de vĂ€rderade risken för hjĂ€rnblödning som lĂ„g. Införandet av en ny riktlinje resulterade i en sĂ€nkning av anvĂ€ndning frĂ„n 60%-40%, trots en informationskampanj som bedrevs för att befrĂ€mja anvĂ€ndandet av den nya riktlinjen.Delarbete 2 genomfördes som en journalgenomgĂ„ng, Vi granskade journalerna för alla patienter som sökt med skallskada pĂ„ en akutmottagning under ungefĂ€r 1 Ă„r. Det framgick att den vanligaste Ă„ldern var 56 Ă„r och att den vanligaste orsaken till huvudskada var fall i samma plan, precis som modern forskning pĂ„ skallskada visar. En grupp som motsvarande ungefĂ€r hĂ€lften av patienterna, som alla hade fallit i samma plan och var under 59 Ă„r, befanns vara fria frĂ„n hjĂ€rnblödning oavsett hur de mĂ„dde nĂ€r de undersöktes pĂ„ akutmottagningen. Konsekvensen av detta skulle kunna vara att man kan skriva hem betydligt fler patienter frĂ„n akuten Ă€n man gör idag utan mer omfattande medicinsk undersökning och utan risk för allvarliga konsekvenser. Det fanns ocksĂ„ indikationer pĂ„ att risken för hjĂ€rnblödning om man behandlas med Trombyl 75mg var högre Ă€n om man behandlas med starkare blodförtunnande medel sĂ„som Waran, nĂ„got som traditionellt anses medföra högre risk för hjĂ€rnblödning i dessa sammanhang.Delarbete 3 gjordes pĂ„ samma sĂ€tt som delarbete 2 med en journalgenomgĂ„ng av alla patienter som sökt akutmottagningen för skallskada under 1 Ă„r för att testa den hypotes som framlades i delarbete 2 om att en stor grupp patienter med fall i samma plan som var under 59 Ă„r och inte tog blodförtunnande mediciner skulle kunna skickas hem utan mer omfattande medicinsk undersökning. Om dagens skandinaviska riktlinje för skallskada utökades med dessa villkor och skulle anvĂ€ndningen av skiktröntgen minskas med 13%. ĂndĂ„ skulle alla hjĂ€rnblödningar som krĂ€vde nĂ„gon form av kirurgisk Ă„tgĂ€rd upptĂ€ckas, det vill sĂ€ga alla allvarliga hjĂ€rnblödningar.12Delarbete 4 och 5 genomfördes med syfte att utreda om S100B som mĂ€ttes i kapillĂ€rt blod samt urin kunde anvĂ€ndas för att utesluta hjĂ€rnblödning efter skallskada. KapillĂ€ra prover tagna pĂ„ samma patient vid samma tillfĂ€lle hade mycket stor spridning och lĂ€mpade sig dĂ€rför inte att anvĂ€nda till detta syfte. Analysmetoden för S100B i urin visade sig vara mycket pĂ„litlig men S100B i urin hade sĂ€mre förmĂ„ga Ă€n det blodprov för S100B, som idag Ă€r standard, att utesluta hjĂ€rnblödning. DĂ€remot visade det sig att en differens mellan standardblodprovet och urinprovet verkade ha bĂ€ttre förmĂ„ga Ă€n dagens blodprov att pĂ„visa hjĂ€rnblödning och att pH i urin förefaller pĂ„verka koncentrationen av S100B i urin.Avhandlingens slutsatser kan sammanfattas i följande punkter: Utvecklande och införande av riktlinjer mĂ„ste ske pĂ„ andra sĂ€tt Ă€n de traditionella om man ska fĂ„ fler att efterleva dem. De riktlinjer som finns bör uppdateras med bakgrund i modernare forskning. KapillĂ€rt S100B bör inte anvĂ€ndas för att utesluta hjĂ€rnblödning men differensen mellan S100B mĂ€tt i blodprov frĂ„n armen och i urin bör testas för att se om det kan ha bĂ€ttre trĂ€ffsĂ€kerhet Ă€n nĂ„got de enskilda proven har
Safety in Road Tunnels â Safety Target Proposal
The purpose of this paper is to propose a quantitative target for assessment of life safety in road tunnels and describe how such a target can be utilized and developed further. The target is developed from an analysis of initiating events, accident statistics and analytical approaches and it makes it possible to tailor the safety concept in individual tunnels to meet the target by means of quantitative risk analyses. The results indicate that the practice proposed is beneficial for both quality and transparency in the decision-making, as well as it can be judged to have the potential to improve cost-efficiency in the safety related work. It is concluded that the target should be calibrated and evaluated with data from real tunnels before implementation and that the resulting safety level from present ruling is assessed. Also, it is concluded that the total cost to realize the safety target is assessed. It is recommended to put more effort on general accident prevention in tunnels compared to surface roads in order to reduce the number of events that may escalate beyond control. It is also recommended that the road tunnel safety learning processes are improved by routine collection, compilation and evaluation of data on road tunnel accidents as well as vehicle-fires and dangerous goods accidents in road traffic as a whole
Högt betestryck ökar albedot pÄ afrikanska savanner
Earlier studies done in the north have shown that grazing increases surface albedo by
reducing shrub height and abundance, and thus have the potential to cool down the local
climate. But what about effect of grazing in other systems? In African savanna grasslands
some grazers are able to transform grass swards into a lawn-like state by regular grazing.
The grazing excludes tall-grass colonizers and the spread of lawn grasses is thus promoted
by grazing. A characteristic of savanna ecosystems is the tree-grass coexistence. Field
experiments have indicated that in the absence of herbivory and fire, woody plant
encroachment in savannas can be high, but grazing lawns seem to be resistant to shrub
invasion. I investigate how the creation of grazing lawns affects the albedo of savanna
grasslands. By comparing albedo between grazing lawns, bunch grass and woody shrubs. I
also quantify the extent of grazing lawns across the. I show that grazing lawns have a
significantly higher albedo than both bunch grass and grass encroached by woody plants
and that albedo increased during the growing season. Albedo decreased when the amount of
bare soil increased, and albedo increased with more grass. The assessment of grazing lawn
distribution in the park showed that lawns in some parts cover 20% of the transect area.
This study shows that grazing lawns, and by extension grazers, could affect the local
climate on African savannas, through a higher albedo
The antiproliferative role of the liver X receptors in breast and colorectal cancer
The liver X receptors (LXR
α
and LXR
ÎČ
) are members of the nuclear receptor superfamily of
ligand activated transcription factors and have
functions as regulators of lipid and glucose
metabolism, as well as inflammatory response. In recent years, several reports have
demonstrated an important role of LXRs
in the control of cell proliferation.
In
Paper I
we demonstrate that LXR activation with synthetic agonist GW3965 leads to a
strong antiproliferative effect in four different
human breast cancer cell
lines. We show that
LXR activation induces an arrest at the G
1
/S check point of the cell cycle with a
hypophosphorylation of retinoblasto
ma protein and a downregulation of cell cycle modulators
such as Skp2, cyclin A2 and cy
clin D1. We further show that
the antiproliferative function of
LXRs is independent of lipid biosynthesis.
In
Paper II
we follow up the results in Paper I to
elucidate more mechanisms of LXR
activation in human breast cancer cell lines. Us
ing microarray analysis, we find both cell line
specific and common LXR target
genes. The common responsive genes that were upregulated
upon LXR activation are annotated
to known metabolic functions of LXR, while the common
downregulated genes mostly include those
with function in cell cycle regulation and
proliferation. Comparing the common downregulat
ed gene set, with br
east cancer tumour
samples and patient data we find
that patients with tumours expr
essing lower levels of these
LXR target genes had better survival compared
to patients with a higher expression of these
genes. In addition, we identify the E2F family
of transcription factor
s as mediators of the
antiproliferative effect of LXR activation.
In
Paper III
we demonstrate that activa
tion of LXRs with
GW3965 decreases proliferation in
human colorectal cell lines with a cell cycle arrest in the G
1
to S phase transition. We
demonstrate a decreased expression of cell
cycle promoters such
as Skp2, CDK1, CDK2,
CDK4, cyclin E, cyclin B1 and c-myc, as
well as hypophosphorylation of retinoblastoma
protein. Moreover, we show that LXR deficient
mice have an increased proliferation in the
colonic crypt compared to wild
type mice. Also, activation of
LXRs with GW3965 reduces
proliferation in the colonic
crypt of wild type mice.
In
Paper IV
we demonstrate that activation of LXRs
dampens the inflammatory response by
downregulating pro-inflammatory
mediators in two different
mouse models of colitis. In
addition, LXR deficient mice have
a faster and more severe di
sease progression. We further
demonstrate that expression of LXR regulated
genes is suppressed in colon samples from
patients with either Crohnâs disease or ulcer
ative colitis compared
to healthy controls.
Inflammatory bowel disease (IBD), including Crohnâs disease and ulcerative colitis, is
associated to increased risk of developing colore
ctal cancer. The data in Paper IV suggests the
potential for LXR mediated inhib
ition of inflammation during IBD,
thus reducing the risk for
developing colorectal cancer
Electrostatic potentials in the downward auroral current region
[1] Assuming a fixed ion density, adiabatic electron motion, and quasi-neutrality, we use the stationary Vlasov equation to derive the self-consistent potential in an auroral flux tube that carries downward current. Our model predicts downward electric fields 2.5 kV. A weak upward electric field at high altitudes reduces the potential, and the potential difference between the ionosphere and magnetosphere is much smaller. Citation: Vedin, J., and K
Omega-3 long-chain polyunsaturated fatty acids supplementation on inflammatory biomakers: a systematic review of randomised clinical trials
Inflammation is part of the normal host response to infection and injury. Eicosanoids, cytokines, chemokines, adhesion molecules and
other inflammatory molecules are frequently produced during this process. Numerous studies in humans have documented the inflammation-limiting properties of omega-3 fatty acids, but only a few have been randomised clinical trials. The aim of this study was to perform
a systematic search of randomised clinical trials on omega-3 fatty acids and inflammatory biomarkers in all subjects including healthy and ill
persons up to February 2011 using PubMed and LILACS databases, defined by a specific equation using MeSH terms and limited to randomised clinical trials; there was no any a priori decision to include some diseases and not others. The quality of each publication was
validated by using the JADAD scale and the CONSORT checklist. Inflammatory biomarkers were considered as primary outcomes.
Twenty-six publications of the last 10 years were selected. Studies included healthy subjects and patients with cardiovascular disease
and other chronic and acute diseases; all reported the number of subjects, type of study, type and doses of omega-3 fatty acids, main outcomes and major inflammatory biomarkers. Dietary omega-3 fatty acids are associated with plasma biomarker levels, reflecting lower levels
of inflammation and endothelial activation in cardiovascular disease and other chronic and acute diseases, including chronic renal disease,
sepsis and acute pancreatitis. However, further research is required before definitive recommendations can be made about the routine use
of omega-3 fatty acids in critically ill patients or with neurodegenerative or chronic renal disease.Instituto de Salud Carlos III del Ministerio de Ciencia e Innovacion Red SAMID, RETIC
RD08/007
Utdelning av naloxon för att förebygga död i heroinöverdos. Studie av opiatberoende patienters attityder till att ingÄ i antidotprogram.
Methods of economic reliability assessment for industrial enterprise in the market economy conditions
The paper dwells upon prospects, topicality and scholarly importance of research into formation and assessment of economic reliability in industrial enterprises as socio-economic systems. The main notions and interconnection of the categories of âstabilityâ and âreliabilityâ of socio-economic systems are presented, based on which the conclusion that these notions are not identical is made. From the standpoint of system-synergetic approach, economic reliability comprises reliability of management system, technical development, conservation activities, human resources management, financial and economic development, marketing activities, and production management. The paper presents main methodological principles of integral estimation of economic reliability of an enterprise in modern conditions. It is suggested to apply E. Harringtonâs desirability function in order to give a quantitative estimate of economic reliability. In conclusion it is pointed out that assessment of industrial enterpriseâs economic reliability can become an effective mechanism of assessing the efficiency of harnessing the manufacturerâs potential and identifying the reserves and inefficient usage of enterprise resources
Empagliflozin in Heart Failure With Predicted Preserved Versus Reduced Ejection Fraction: Data From the EMPA-REG OUTCOME Trial
Background: In the EMPA-REG OUTCOME trial, ejection fraction (EF) data were not collected. In the subpopulation with heart failure (HF), we applied a new predictive model for EF to determine the effects of empagliflozin in HF with predicted reduced (HFrEF) vs preserved (HFpEF) EF vs no HF. /
Methods and Results: We applied a validated EF predictive model based on patient baseline characteristics and treatments to categorize patients with HF as being likely to have HF with mid-range EF (HFmrEF)/HFrEF (EF <50%) or HFpEF (EF â„50%). Cox regression was used to assess the effect of empagliflozin vs placebo on cardiovascular death/HF hospitalization (HHF), cardiovascular and all-cause mortality, and HHF in patients with predicted HFpEF, HFmrEF/HFrEF and no HF. Of 7001 EMPA-REG OUTCOME patients with data available for this analysis, 6314 (90%) had no history of HF. Of the 687 with history of HF, 479 (69.7%) were predicted to have HFmrEF/HFrEF and 208 (30.3%) to have HFpEF. Empagliflozin's treatment effect was consistent in predicted HFpEF, HFmrEF/HFrEF and no-HF for each outcome (HR [95% CI] for the primary outcome 0.60 [0.31â1.17], 0.79 [0.51â1.23], and 0.63 [0.50â0.78], respectively; P interaction = 0.62). /
Conclusions: In EMPA-REG OUTCOME, one-third of the patients with HF had predicted HFpEF. The benefits of empagliflozin on HF and mortality outcomes were consistent in nonHF, predicted HFpEF and HFmrEF/HFrEF
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