Locking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010

Located at the northern shore of Iceland, the Tjörnes Fracture Zone (TFZ) is a 120 km offset in the mid-Atlantic Ridge that connects the offshore Kolbeinsey Ridge to the on-land Northern Volcanic Zone. This transform zone is seismically one of the most active areas in Iceland, exposing the population to a significant risk. However, the kinematics of the mostly offshore area with its complex tectonics have not been adequately resolved and the seismic potential of the two main transform structures within the TFZ, the Grímsey Oblique Rift (GOR) and the Húsavík Flatey Fault (HFF) in particular, is not well known. In summer 2006, we expanded the number of continuous GPS (CGPS) stations in the area from 4 to 14. The resulting GPS velocities after four years of data collection show that the TFZ accommodates the full plate motion as it is predicted by the MORVEL plate motion model. In addition, ENVISAT interferograms reveal a transient uplift signal at the nearby Theistareykir central volcano with a maximum line-of-sight uplift of 3 cm between summers of 2007 and 2008. We use a combination of an interseismic backslip and a Mogi model in a homogeneous, elastic half-space to describe the kinematics within the TFZ. With a non-linear optimization approach we fit the GPS observations and estimate the key model parameters and their uncertainties, which are (among others) the locking depth, the partition of the transform motion between the two transform structures within the TFZ and the slip rate on the HFF. We find a shallow locking depth of 6.3+1.7- 1.2 km and transform motion that is accommodated 34 ± 3 per cent by the HFF and 66 ± 3 per cent by the GOR, resulting in a slip velocity of 6.6 ± 0.6 mm yr-1 for the HFF. Assuming steady accumulation since the last two large M6.5 earthquakes in 1872 the seismic potential of the fault is equivalent to a Mw6.8 ± 0.1 even

CT and MRI assessment and characterization using segmentation and 3D modeling techniques: applications to muscle, bone and brain

This paper reviews the novel use of CT and MRI data and image processing tools to segment and reconstruct tissue images in 3D to determine characteristics of muscle, bone and brain.This to study and simulate the structural changes occurring in healthy and pathological conditions as well as in response to clinical treatments. Here we report the application of this methodology to evaluate and quantify: 1. progression of atrophy in human muscle subsequent to permanent lower motor neuron (LMN) denervation, 2. muscle recovery as induced by functional electrical stimulation (FES), 3. bone quality in patients undergoing total hip replacement and 4. to model the electrical activity of the brain. Study 1: CT data and segmentation techniques were used to quantify changes in muscle density and composition by associating the Hounsfield unit values of muscle, adipose and fibrous connective tissue with different colors. This method was employed to monitor patients who have permanent muscle LMN denervation in the lower extremities under two different conditions: permanent LMN denervated not electrically stimulated and stimulated. Study 2: CT data and segmentation techniques were employed, however, in this work we assessed bone and muscle conditions in the pre-operative CT scans of patients scheduled to undergo total hip replacement. In this work, the overall anatomical structure, the bone mineral density (BMD) and compactness of quadriceps muscles and proximal femoral was computed to provide a more complete view for surgeons when deciding which implant technology to use. Further, a Finite element analysis provided a map of the strains around the proximal femur socket when solicited by typical stresses caused by an implant press fitting. Study 3 describes a method to model the electrical behavior of human brain using segmented MR images. The aim of the work is to use these models to predict the electrical activity of the human brain under normal and pathological conditions by developing detailed 3D representations of major tissue surfaces within the head, with over 12 different tissues segmented. In addition, computational tools in Matlab were developed for calculating normal vectors on the brain surface and for associating this information with the equivalent electrical dipole sources as an input into the model

Immunization coverage in the Monkey Bay Head zone Malawi

Hægt er að lesa greinina í heild sinni með því að smella á hlekkinn View/OpenOBJECTIVE: To assess the immunization coverage of children in the Monkey Bay head zone, Malawi where the Icelandic International Development Agency (ICEIDA) has been working to improve health care services in the recent years. MATERIALS AND METHODS: A 30 by 7 cluster sample survey, as defined by WHO's Expanded Programme on Immunization (EPI) was conducted to estimate immunization coverage of children aged 12-23 months for tuberculosis (BCG), diphtheria, tetanus and pertussis (DTP), polio (OPV) and measles immunizations. The Head Zone consists of 97 villages with a population of around 105,000 inhabitants. Five health centres provide immunization services in the area. In total were 217 children in 30 clusters randomly selected and their immunization status by card or history registered. RESULTS: Immunization coverage by card or history was 97% for BCG, and 99%, 95% and 85% for DTP1, DTP2 and DTP3 respectively. Coverage of OPV1, OPV2 and OPV3 by card or history was 99%, 93% and 85% respectively. Coverage for measles by card or history was 78%. Fully immunized children by card or history were 152 or 70%. Two children had not received any immunizations. Drop-out rate from DTP1 to DTP3 vaccination by immunization card or history was 14.5%, and drop-out from DTP1 to Measles by card or history was 21%. CONCLUSION: These results indicate that access to childhood immunization in the Monkey Bay head zone is good while drop-out rate is high. This indicates that access to health services is adequate. However, the coverage of measles appears to be insufficient to prevent outbreaks, and must be improved. The efficacy in delivering immunization can be improved and enhanced utilization of the services offered should be sought.Tilgangur: Að leggja mat á þekjun bólusetningar barna í Monkey Bay héraði í Malaví þar sem að Þróunarsamvinnustofnun Íslands (ÞSSÍ) hefur unnið að uppbyggingu heilsugæslu undanfarin ár. Efniviður og aðferðir: Notast var við aðferðir alþjóðaheilbrigðismálastofnunarinnar (WHO) til þess að meta þekjun bólusetningar barna á aldrinum 12-23 mánaða í Monkey Bay héraði. Í héraðinu búa um það bil 105.000 íbúar í 97 þorpum. Fimm heilsugæslustöðvar veita þjónustu á svæðinu. Börn á svæðinu voru bólusett fyrir berklum (BCG), barnaveiki, stífkrampa og kíghósta (DTP), mænu­veiki (OPV) og mislingum. Ef börn voru ekki bólusett voru ástæður þess skráðar. Valin voru 217 börn af handahófi í 30 þorpum/klösum (clusters) og þekjun metin með skoðun bólusetningarkorta eða samkvæmt heilsufarssögu. Niðurstöður: Þekjun bólusetningar miðað við kort eða sögu var 97% fyrir BCG, og 99%, 95% og 85% fyrir DTP1, DTP2 og DTP3. Þekjun OPV1, OPV2 og OPV3 miðað við kort eða sögu var 99%, 93% og 85%. Þekjun mislinga miðað við kort eða sögu var 78%. Fullbólusett börn miðað við kort eða sögu voru 152, eða 70%. Tvö börn höfðu ekki fengið neinar bólu­setningar. Brottfall milli DTP1 og DTP3 miðað við kort eða sögu var 14,5 prósentustig, og brottfall milli DTP1 og mislinga var 21 prósentustig. Ályktun: Aðgengi að bólusetningu á svæðinu virðist gott. Brottfall frá fyrstu bólusetningu til síðustu er áhyggjuefni, sérstaklega hvað varðar mislinga en sú bólusetning er einnig oft gefin of seint. Því verður að huga að leiðum til þess að auka skilvirkni þeirrar þjónustu sem er í boði

Epidemiology of Spinal Cord Injury in Iceland from 1975 to 2014

Efst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinnInngangur: Mænuskaði er meðal alvarlegustu afleiðinga slysa og þar sem ekki hefur tekist að finna lækningu við mænuskaða hefur áhersla verið lögð á forvarnarstarf. Nýgengi mænuskaða er breytilegt milli landa og ýmsar breytingar hafa orðið á faraldsfræði mænuskaða í áranna rás. Markmið þessarar rannsóknar var að kanna faraldsfræði mænuskaða af völdum slysa á Íslandi og leita áhættuþátta sem nýta mætti í forvarnarskyni. Efniviður og aðferðir: Farið var afturskyggnt yfir sjúkraskrár allra sem greindust með mænuskaða samkvæmt ICD-9/ICD-10 á Landspítala á árunum 1975-2014. Upplýsinga var aflað um nýgengi, aldur, kynjaskiptingu og orsakir. Notaður var skalinn American Spinal Injury Association Impairment Scale (AIS) við mat á alvarleika mænuskaða. Niðurstöður: Á rannsóknartímabilinu hlutu 233 einstaklingar mænuskaða af völdum áverka, eða 26 á hverja milljón íbúa á ári að meðaltali. Karlmenn voru 73% og meðalaldurinn 39 ár. Umferðarslys voru algengasta orsök mænuskaða. Oftast var um að ræða bílveltur í dreifbýli og í að minnsta kosti helmingi tilfella voru bílbelti ekki notuð. Fall var næstalgengasta orsök mænuskaða en í þeim orsakaflokki var meðalaldurinn hæstur. Reiðmennsku- og vetraríþróttaslys voru algengust íþrótta- og tómstundaslysa. Í um þriðjungi mænuskaðatilfella var um að ræða alskaða á mænu. Við útskrift höfðu 9% náð fullum bata. Ályktun: Mikilvægt er að efla enn frekar forvarnir og áróður í tengslum við bílbeltanotkun og öryggi á vegum landsins. Einnig þarf að leita leiða til að fækka mænuskaðatilfellum vegna falls, svo sem með því að kanna nánar ástæður falla hjá eldra fólki og bæta öryggisreglur á vinnustöðum. Hugsanlega mætti fækka íþrótta- og tómstundaslysum með forvarnaraðgerðum og bættum öryggisbúnaði.Introduction: Traumatic spinal cord injury (TSCI) is serious and often has long-term consequences. Since no cure has been found the emphasis has been on preventive measures. The incidence of TSCI varies between countries and the epidemiology has been changing. The aim of this study was to gather epidemiological data on patients with TSCI in Iceland and search for risk factors. Material and methods: Hospital records of everyone diagnosed with TSCI in 1975-2014 admitted to Landspitali University Hospital were reviewed and information gathered on incidence, age, gender and causes of injury. The American Spinal Injury Association Impairment Scale (AIS) was used to assess the extent of TSCI. Results: A total of 233 patients were diagnosed with TSCI during the study period or 26 per million annually on average. Males were 73% and the mean age was 39 years. Traffic accidents were the most common cause of TSCI. The majority were car rollovers in rural areas. Around 50% did not use a seatbelt. The second most common cause of TSCI were falls. The most common sport/leisure accidents were those related to horseback-riding and winter sports. A third of patients had a complete SCI. At discharge 9% had gained full recovery. Conclusions: Safe roads and good traffic culture are essential factors in the prevention of serious traffic accidents. Strict safety regulations in the work place and an investigation of causes of falls amongst the elderly could decrease SCIs due to falls. Further preventive measures and protective equipment could possibly be of use in sport- or leisure-related activities

A large rock avalanche onto Morsarjökull glacier, south-east Iceland. Its implications for ice-surface evolution and glacier dynamics

In spring 2007, a large rock avalanche descended onto the Morsárjökull valley glacier in southeast Iceland, leaving one fifth of the glacier buried. The insulating effect of the deposit on the ice was quickly observed as a difference in the ablation between the exposed ice and that under the deposit. After three melt seasons, the ice surface under the deposit was 29 m above the surrounding glacier surface. A reduced rate of ice melting beneath the area of the deposit would likely alter the longitudinal profile of the glacier

Improving Planning and Post-Operative Assessment for Total Hip Arthroplasty.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Total Hip Arthroplasty (THA) remains the gold standard of treatment for patients who suffer with a variety of hip-related pathological degeneration or trauma. These patients often exhibit significantly less post-operative pain and an increase in the range of motion of the joint, but there are still relatively common instances of debilitating periprosthetic complications that call into question the method for pre-surgical implant choice. Currently, there are two principal options for THA prostheses: cemented or non cemented. Utilizing the cemented procedure ensures a faster acquisition of adequate implant stability than with the non cemented procedure, but can eventually lead to an increased periprosthetic fracture risk. Non cemented prosthetic stems are more frequently revised within the first few years following THA due to periprosthetic fracture, but non cemented revision surgeries generally result in fewer complications than those of cemented implants. Surgeons typically rely on experience or simple patient metrics such as age and sex to prescribe which implant procedure is optimal, and while this may work for most patients, there is a clear need to analyze more rigoriously patient conditions that correlate to optimal post-THA outcomes. The results from the investigation reported herein indicate that an understanding of how the percent composition and quality of a patient's quadriceps muscle in both healthy and operated legs may be a better indicator for prosthetic choice. Additionally, these data emphasize that the traditional metrics of age and sex inadequately predict changes in quadriceps composition and quality and thereby have comparatively minor utility in determining the patient-appropriate prosthetic type.Total Hip Arthroplasty, Prosthetic selection, Muscle size and quality, Anatomical modeling, Surgical planning.University Hospital Landspitali Scientific fun

Structural Analysis of Casings in High Temperature Geothermal Wells in Iceland

ABSTRACT Large temperature changes are a central design concern in a diverse range of structures. Large and quick wellbore temperature changes in high temperature geothermal wells, e.g. during discharge and quenching of wells, produce large thermal stresses in the production casing which can cause casing failures. The wellbore temperature change during discharge causes the wellhead to rise due to thermal expansion of the casings, since the wells are constructed of several concentric steel casings which are fully cemented to the top. The structural integrity of such casings is essential for the utilization of high temperature geothermal wells. The casings in connection to the wellhead form a structural system which involves nonlinear interaction of the contacting surfaces. Therefore, the structural system is analyzed numerically with the use of the nonlinear finite element method (FEM). Three FEM models are presented here with the purpose of evaluating the structural integrity of high temperature geothermal well casings. A load history is used in the analysis, consisting of transient wellbore temperature and pressure changes

Health-related quality of life of patients before and after treatment

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenObjective: Health-related quality of life (HRQL) is increasingly used to estimate needs for medical treatment, to evaluate its outcome and quality of care. The aim of this study was to compare the HRQL of several diagnostic groups before and after treatment with the HL-test (HL = IQL, Icelandic Quality of Life test) and to study its validity for measuring changes in quality of life. Material and methods: Patients on waiting lists for coronary catheterization, orthopedic or urologic operations, patients in psychiatric out-patient treatment and patients entering treatment for alcohol dependence were asked to fill in the HL-test, a total of 1195 patients. Three months after treatment they were retested. The results of tests were standarized with population norms available to make them directly comparable with those of the general population. Results: The response rate was 75% in each round. The HRQL of all patients was reduced in all aspects compared to that of the general population, that of the heart and urology patients less so than that of the orthopedic and psychiatric patients. Each group had a specific profile, especially marked for the orthopedic and psychiatric patients. Following treatment the HRQL or some aspects of it improved in all groups, especially for those which it had been most impaired. Conclusions: Studies of HRQL provide information useful for planning and delivery of health services. The HL-test is an instrument with good validity and reliability which is easy to use for such studies.Tilgangur: Heilsutengd lífsgæði (HL) hafa í vaxandi mæli verið notuð til að meta þörf fyrir læknismeðferð, árangur hennar og gæði umönnunar. Tilgangur rannsóknarinnar var að bera saman heilsutengd lífsgæði nokkurra sjúklingahópa fyrir og eftir meðferð með HL-prófinu og athuga frekar réttmæti þess og getu til að mæla breytingar á líðan fólks. Efniviður og aðferðir: Sjúklingar sem biðu hjartaþræðingar, aðgerða á bæklunar- eða þvagfæraskurðdeild, voru í meðferð á göngudeild geðdeildar eða voru að byrja í meðferð vegna áfengissýki, samtals 1195 sjúklingar, voru beðnir að svara HL-prófinu. Þremur mánuðum eftir meðferð voru þeir beðnir að svara prófinu aftur. Niðurstöður prófanna voru staðlaðar samkvæmt viðmiðum eftir kyni og aldri svo að hægt væri að sjá beint hvernig þær viku frá því sem almennt gerist. Niðurstöður: Heildarsvörun var 75% í hvorri umferð. Allir sjúklingarnir voru með skert lífsgæði á öllum þáttum prófsins miðað við jafnaldra þeirra, hjarta- og þvagfærasjúklingar minna en bæklunar- og geðsjúklingar. Skerðingin var sérkennandi fyrir hvern hóp, sérstaklega aðgreindust bæklunar- og geðsjúklingarnir greinilega hvor frá öðrum og frá hinum. Eftir meðferð bötnuðu lífsgæðin eða einhverjir þættir þeirra hjá öllum hópunum, mest þeir sem höfðu verið lakastir fyrir. Ályktanir: Með rannsóknum á heilsutengdum lífsgæðum er unnt að afla frekari þekkingar sem nýtist við skipulagningu og framkvæmd heilbrigðisþjónustu. HL-prófið er einfalt tæki til slíkra rannsókna, réttmætt og áreiðanlegt