1,566 research outputs found
Climate change adaptation in agriculture; the use of multi-scale modelling and stakeholder participation in the Netherlands
Abstract about a research project to develop a methodology to assess adaptation of agriculture to climatic and socio-economic changes at multiple scales, with a first application in the Province of Flevoland, the Netherlands
Geochemical comparison of K-T boundaries from the Northern and Southern Hemispheres
Closely spaced (cm-scale) traverses through the K-T boundary at Stevns Klint (Denmark), Woodside Creek (New Zealand) and a new Southern Hemisphere site at Richards Bay (South Africa) were subjected to trace element and isotopic (C, O, Sr) investigation. Intercomparison between these data-sets, and correlation with the broad K-T database available in the literature, indicate that the chemistry of the boundary clays is not globally constant. Variations are more common than similarities, both of absolute concentrations, and interelement ratios. For example, the chondrite normalized platinum-group elements (PGE) patterns of Stevns Klint are not like those of Woodside Creek, with the Pt/Os ratios showing the biggest variation. These differences in PGE patterns are difficult to explain by secondary alteration of a layer that was originally chemically homogeneous, especially for elements of such dubious crustal mobility as Os and Ir. The data also show that enhanced PGE concentrations, with similar trends to those of the boundary layers, occur in the Cretaceous sediments below the actual boundary at Stevns Klint and all three the New Zealand localities. This confirms the observations of others that the geochemistry of the boundary layers apparently does not record a unique component. It is suggested that terrestrial processes, eg. an extended period of Late Cretaceous volcanism can offer a satisfactory explanation for the features of the K-T geochemical anomaly. Such models would probably be more consistent with the observed stepwise, or gradual, palaeontological changes across this boundary, than the instant catastrophe predicated by the impact theory
Severe fatigue and related factors in cancer patients before the initiation of treatment
It is generally known that fatigue is a common symptom during cancer treatment, and in cancer survivors. However, fatigue was never studied after diagnosis, before cancer treatment was initiated. This study investigated the prevalence of severe fatigue, and related factors, in cancer patients before the initiation of treatment. One hundred and seventy-nine patients with various malignancies were assessed before start of treatment with curative intention, including the Checklist Individual Strength, Sickness Impact Profile, Beck Depression Inventory Primary Care, Symptom Checklist-90, and six Numeric Rating Scales to measure fatigue, pain and physical activity. To test which factors contributed to severe fatigue a logistic regression analysis was performed. In total 23.5% patients were severely fatigued, varying between diagnoses; prostate cancer (14.3%), breast cancer (20.3%), and gastrointestinal cancer (28.1%). Currently lower physical activity (P=0.013), more depressive mood (P=0.014), impaired sleep and rest during the day and night (P=0.045), and fatigue 1 year before diagnosis (P=0.005) contributed to severe fatigue. Relatively large numbers of cancer patients already experience severe fatigue before initiation of treatment, varying between 14–28%. The factors that contributed to severe fatigue at this stage were physical activity, depressive mood, impaired sleep and rest, and fatigue 1 year before diagnosis
Clinical Outcome and Morphologic Analysis after Endovascular Aneurysm Repair Using the Excluder Endograft
OBJECTIVE: Long-term follow-up after endovascular aneurysm repair (EVAR) is very scarce, and doubt remains regarding the durability of these procedures. We designed a retrospective cohort study to assess long-term clinical outcome and morphologic changes in patients with abdominal aortic aneurysms (AAAs) treated by EVAR using the Excluder endoprosthesis (W. L. Gore and Associates, Flagstaff, Ariz).
METHODS: From 2000 to 2007, 179 patients underwent EVAR in a tertiary institution. Clinical data were retrieved from a prospective database. All patients treated with the Excluder endoprosthesis were included. Computed tomography angiography (CTA) scans were retrospectively analyzed preoperatively, at 30 days, and at the last follow-up using dedicated tridimensional reconstruction software. For patients with complications, all remaining CTAs were also analyzed. The primary end point was clinical success. Secondary end points were freedom from reintervention, sac growth, types I and III endoleak, migration, conversion to open repair, and AAA-related death or rupture. Neck dilatation, renal function, and overall survival were also analyzed.
RESULTS: Included were 144 patients (88.2% men; mean age, 71.6 years). Aneurysms were ruptured in 4.9%. American Society of Anesthesiologists classification was III/IV in 61.8%. No patients were lost during a median follow-up of 5.0 years (interquartile range, 3.1-6.4; maximum, 11.2 years). Two patients died of medical complications ≤ 30 days after EVAR. The estimated primary clinical success rates at 5 and 10 years were 63.5% and 41.1%, and secondary clinical success rates were 78.3% and 58.3%, respectively. Sac growth was observed in 37 of 142 patients (26.1%). Cox regression showed type I endoleak during follow-up (hazard ratio, 3.74; P = .008), original design model (hazard ratio, 3.85; P = .001), and preoperative neck diameter (1.27 per mm increase, P = .006) were determinants of sac growth. Secondary interventions were required in 32 patients (22.5%). The estimated 10-year rate of AAA-related death or rupture was 2.1%. Overall life expectancy after AAA repair was 6.8 years.
CONCLUSIONS: EVAR using the Excluder endoprosthesis provides a safe and lasting treatment for AAA, despite the need for maintained surveillance and secondary interventions. At up to 11 years, the risk of AAA-related death or postimplantation rupture is remarkably low. The incidences of postimplantation sac growth and secondary intervention were greatly reduced after the introduction of the low-permeability design in 2004
Education on organ donation and transplantation in primary school; teachers' support and the first results of a teaching module
Organ and tissue donation can also involve children. Because of its sensitivity, this topic requires careful decision making. Children have the ability to carefully reflect on this subject and enjoy participating in family discussions about it. Therefore, what children need is proper information. When schools are used to educate children about this subject, information about teacher support for this type of lesson along with its effects on the depth of family discussions is important.A questionnaire was sent to all 7,542 primary schools in the Netherlands. The goal was to gather information on teachers' perspectives about a neutral lesson devoted to organ and tissue donation, and also on the best age to start giving such a lesson. The second part of our study examined the effects of a newly developed lesson among 269 primary school pupils. The school response was 23%. Of these, 70% were positive towards a lesson; best age to start was 10-11 years. Pupils reported 20% more family discussions after school education and enjoyed learning more about this topic. There is significant support in primary schools for a school lesson on organ and tissue donation. Educational programs in schools support family discussions
The Effect of Osteoarthritis of the Hip or Knee on Work Participation
In our systematic literature search, we included studies involving patients with hip or knee osteoarthritis (OA) and outcome measures of work participation. Methodological quality was assessed using 11 criteria; a qualitative data analysis was performed. Fifty-three full-text articles were selected out of 1861 abstracts; finally, data were extracted from 14 articles. Design, populations, definitions, and measurements in the studies showed large variations; work outcomes were often only secondary objectives. The outcomes were summarized as showing a mild negative effect of OA on work participation. Many patients had paid work and managed to stay at work despite limitations. However, research on the effect of OA on work participation is scarce and the methodological quality is often insufficient. The longitudinal course of work participation in individuals with OA has not been described completely. (First Release June 15 2011; J Rheumatol 2011;38:1835-43; doi:10.3899/jrheum.101210
Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair
Objective: Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs.
Methods: All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images.
Results: A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value = 7.9, p 5 mm (HR 3.1, 95% CI 1.4 - 6.9).
Conclusion: AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.info:eu-repo/semantics/publishedVersio
Neonatal Hemoglobin Levels in Preterm Infants Are Associated with Early Neurological Functioning
Background: Neonatal anemia may compromise oxygen transport to the brain. The effects of anemia and cerebral oxygenation on neurological functioning in the early neonatal period are largely unknown. Objective: This study aimed to determine the association between initial hemoglobin levels (Hb) and early neurological functioning in preterm infants by assessing their general movements (GMs). Methods: A retrospective analysis of prospectively collected data on preterm infants born before 32 weeks of gestation was conducted. We excluded infants with intraventricular hemorrhage > grade II. On day 8, we assessed infants' GMs, both generally as normal/abnormal and in detail using the general movement optimality score (GMOS). We measured cerebral tissue oxygen saturation (r(c)SO(2)) on day 1 using near-infrared spectroscopy. Results: We included 65 infants (median gestational age 29.9 weeks [IQR 28.2-31.0]; median birth weight 1,180 g [IQR 930-1,400]). Median Hb on day 1 was 10.3 mmol/L (range 4.2-13.7). Lower Hb on day 1 was associated with a higher risk of abnormal GMs (OR = 2.3, 95% CI: 1.3-4.1) and poorer GMOSs (B = 0.9, 95% CI: 0.2-1.7). Hemoglobin strongly correlated with r(c)SO(2) (rho = 0.62, p < 0.01). Infants with lower r(c)SO(2) values tended to have a higher risk of abnormal GMs (p = 0.06). After adjusting for confounders, Hb on day 1 explained 44% of the variance of normal/abnormal GMs and r(c)SO(2) explained 17%. Regarding the explained variance of the GMOS, this was 25% and 16%, respectively. Conclusions: In preterm infants, low Hb on day 1 is associated with impaired neurological functioning on day 8, which is partly explained by low cerebral oxygenation
Intestinal Oxygenation and Survival After Surgery for Necrotizing Enterocolitis:An Observational Cohort Study
OBJECTIVE: To assess whether regional intestinal oxygen saturation (rintSO2) and regional cerebral oxygen saturation (rcSO2) measurements aid in estimating survival of preterm infants after surgery for NEC. SUMMARY OF BACKGROUND DATA: Predicting survival after surgery for NEC is difficult yet of the utmost importance for counseling parents. METHODS: We retrospectively studied prospectively collected data of preterm infants with surgical NEC who had available rintSO2 and rcSO2 values measured via near-infrared spectroscopy 0-24 hours preoperatively. We calculated mean rintSO2 and rcSO2 for 60-120 minutes for each infant. We analyzed whether preoperative rintSO2 and rcSO2 differed between survivors and non-survivors, determined cut-off points, and assessed the added value to clinical variables. RESULTS: We included 22 infants, median gestational age 26.9 weeks [interquartile range (IQR): 26.3-28.4], median birth weight 1088 g [IQR: 730-1178]. Eleven infants died postoperatively. Preoperative rintSO2, but not rcSO2, was higher in survivors than in non-survivors [median: 63% (IQR: 42-68) vs 29% (IQR: 21-43), P 53% survived, whereas all infants with rintSO2 <35% died. Median C-reactive protein [138 mg/L (IQR: 83-179) vs 73 mg/L (IQR: 12-98), P < 0.01), lactate [1.1 mmol/L (IQR: 1.0-1.6) vs 4.6 mmol/L (IQR: 2.8-8.0), P < 0.01], and fraction of inspired oxygen [25% (IQR: 21-31) vs 42% (IQR: 30-80), P < 0.01] differed between survivors and non-survivors. Only rintSO2 remained significant in the multiple regression model. CONCLUSIONS: Measuring rintSO2, but not rcSO2, seems of added value to clinical variables in estimating survival of preterm infants after surgery for NEC. This may help clinicians in deciding whether surgery is feasible and to better counsel parents about their infants' chances of survival
Comparative study of an Eden model for the irreversible growth of spins and the equilibrium Ising model
The Magnetic Eden Model (MEM) with ferromagnetic interactions between
nearest-neighbor spins is studied in dimensional rectangular geometries
for . In the MEM, magnetic clusters are grown by adding spins at the
boundaries of the clusters. The orientation of the added spins depends on both
the energetic interaction with already deposited spins and the temperature,
through a Boltzmann factor. A numerical Monte Carlo investigation of the MEM
has been performed and the results of the simulations have been analyzed using
finite-size scaling arguments. As in the case of the Ising model, the MEM in is non-critical (only exhibits an ordered phase at ). In
the MEM exhibits an order-disorder transition of second-order at a finite
temperature. Such transition has been characterized in detail and the relevant
critical exponents have been determined. These exponents are in agreement
(within error bars) with those of the Ising model in 2 dimensions. Further
similarities between both models have been found by evaluating the probability
distribution of the order parameter, the magnetization and the susceptibility.
Results obtained by means of extensive computer simulations allow us to put
forward a conjecture which establishes a nontrivial correspondence between the
MEM for the irreversible growth of spins and the equilibrium Ising model. This
conjecture is certainly a theoretical challenge and its confirmation will
contribute to the development of a framework for the study of irreversible
growth processes.Comment: 21 pages, 11 figure
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