Simulation des Ausbreitungsverhaltens von Gasen und Salzwasserin oberflächennahen Aquiferen nach einer Leckage aus einem geologischen Speicher

Werden Fluide im geologischen Untergrund gespeichert besteht ein Restrisiko, dass Gase und verdrängtes Salzwasser entweichen und über hydraulische Wegsamkeiten in oberflachennahe Schutzgutformationen gelangen. Entsprechende Grundwasserleiter müssen einem Monitoring zur frühzeitigen Detektion einer potentiellen Leckage unterzogen werden. Die laterale Ausbreitung von CO2 kann in einer Speicherformation eine im 100er km2 Bereich große Fläche einnehmen. Da eine Migration von Gasen und/oder Salzwasser nicht notwendigerweise senkrecht bis an die Oberfläche stattfindet, vergrößert sich der potentiell gefährdete Bereich. Allerdings kann, abhängig von der Leckagerate, der durch die Leckage beeinflusste Bereich im Vergleich zu der gesamt gefährdeten Fläche klein sein. Daher muss in einem großen Bereich eine unter Umständen kleine Leckage entdeckt werden. Hier müssen geeignete Monitoringmethoden angewendet werden, die sensitiv genug sind, um eine Leckage innerhalb kurzer Zeiträume zu detektieren. Um solche Methoden evaluieren zu können, braucht man allerdings eine gute Vorstellung davon, wie ein betroffenes Areal aussehen könnte. Dieser Aspekt wird in der vorliegenden Arbeit mit numerischen Modellen untersucht werden. Zunächst wird die Frage erörtert, welche Aquiferparameter die Ausbreitung der Gase CO2, H2, CH4 und Luft – wobei der Schwerpunkt der Arbeit auf der Ausbreitung von CO2 liegt – sowie von Salzwasser beeinflussen und wie sich ein durch diese Substanzen entstehender Impakt räumlich und zeitlich ausbreitet.To counter the anthropogenically influenced climate change, the use of renewable energies and methods to reduce the global CO2 output are required. Underground geological storage of gases can contribute to these aims. CO2 can be stored permanently and other gases like hydro-gen, methane or compressed air can be used to buffer energy. But there is a risk remaining that gases leak from the reservoir into protected goods such as shallow potable aquifers or that saline water is pressed upwards. Therefore these aquifers have to be monitored for an early detection of leakages, as laws dealing with underground geological storage of CO2 are already insisting. The lateral expansion of gases in a storage formation can cover an area up to 100 km2. Since CO2 and/or saltwater will not necessarily migrate vertically on a direct path to the surface, one can assume that the potentially affected area is even larger. On the other hand, the impact of a leakage can be rather small, depending on the leakage rate. Hence, a probably small leakage has to be discovered on a large area. Suited monitoring methods which are sensitive enough to detect leakages in a timely manner have to be used. To evaluate such methods, an understand-ing of the impact of such leakages is necessary. The present study aims to investigate this aspect using numerical models. It is discussed, which parameters influence the spreading of gases – main focus of this work is on CO2 – and salt water and how such an impact develops over time and space

Letter to the Editor regarding the article: "identifying pre-hospital factors associated with outcome for major trauma patients in a regional trauma network: An exploratory study"

The aim of this Letter to the Editor was to report some methodological shortcomings in a recently published article. Issues regarding missing values and overfitting are mentioned. First, Complete Case (CC) analysis was used instead of an imputation method. Second, there was a high chance of overfitting and lack of model validation. In conclusion, the results of this study should be interpret with caution and further research is necessary

The volume-outcome relationship among severely injured patients admitted to English major trauma centres : a registry study

Background Many countries have centralized and dedicated trauma centres with high volumes of trauma patients. However, the volume-outcome relationship in severely injured patients (Injury Severity Score (ISS) > 15) remains unclear. The aim of this study was to determine the association between hospital volume and outcomes in Major Trauma Centres (MTCs). Methods A retrospective observational cohort study was conducted using the Trauma Audit and Research Network (TARN) consisting of all English Major Trauma Centres (MTCs). Severely injured patients (ISS > 15) admitted to a MTC between 2013 and 2016 were included. The effect of hospital volume on outcome was analysed with random effects logistic regression models with a random intercept for centre and was tested for nonlinearity. Primary outcome was in-hospital mortality. Results A total of 47,157 severely injured patients from 28 MTCs were included in this study. Hospital volume varied from 69 to 781 severely injured patients per year. There were small between-centre differences in mortality after adjusting for important demographic and injury severity characteristics (adjusted 95% odds ratio range: 0.99–1.01). Hospital volume was found to be linear and not associated with in-hospital mortality (adjusted odds ratio (aOR) 1.02 per 10 patients, 95% confidence interval (CI) 0.68–1.54, p = 0.92). Conclusions Despite the large variation in volume of the included MTCs, no relationship between hospital volume and outcome of severely injured patients was found. These results suggest that centres with similar structure and processes of care can achieve comparable outcomes in severely injured patients despite the number of severely injured patients they treat

Magnetic field effect on the dielectric constant of glasses: Evidence of disorder within tunneling barriers

The magnetic field dependence of the low frequency dielectric constant $e_r$(H) of a structural glass a - SiO2 + xCyHz was studied from 400 mK to 50 mK and for H up to 3T. Measurement of both the real and the imaginary parts of $e_r$ is used to eliminate the difficult question of keeping constant the temperature of the sample while increasing H: a non-zero $e_r$(H) dependence is reported in the same range as that one very recently reported on multicomponent glasses. In addition to the recently proposed explanation based on interactions, the reported $e_r$(H) is interpreted quantitatively as a consequence of the disorder lying within the nanometric barriers of the elementary tunneling systems of the glass.Comment: latex Bcorrige1.tex, 5 files, 4 figures, 7 pages [SPEC-S02/009

Quantization of the Hall conductivity well beyond the adiabatic limit in pulsed magnetic fields

We measure the Hall conductivity, $\sigma_{xy}$, on a Corbino geometry sample of a high-mobility AlGaAs/GaAs heterostructure in a pulsed magnetic field. At a bath temperature about 80 mK, we observe well expressed plateaux in $\sigma_{xy}$ at integer filling factors. In the pulsed magnetic field, the Laughlin condition of the phase coherence of the electron wave functions is strongly violated and, hence, is not crucial for $\sigma_{xy}$ quantization.Comment: 4 pages, 4 figures, submitted to PR

Disease model curation improvements at Mouse Genome Informatics

Optimal curation of human diseases requires an ontology or structured vocabulary that contains terms familiar to end users, is robust enough to support multiple levels of annotation granularity, is limited to disease terms and is stable enough to avoid extensive reannotation following updates. At Mouse Genome Informatics (MGI), we currently use disease terms from Online Mendelian Inheritance in Man (OMIM) to curate mouse models of human disease. While OMIM provides highly detailed disease records that are familiar to many in the medical community, it lacks structure to support multilevel annotation. To improve disease annotation at MGI, we evaluated the merged Medical Subject Headings (MeSH) and OMIM disease vocabulary created by the Comparative Toxicogenomics Database (CTD) project. Overlaying MeSH onto OMIM provides hierarchical access to broad disease terms, a feature missing from the OMIM. We created an extended version of the vocabulary to meet the genetic disease-specific curation needs at MGI. Here we describe our evaluation of the CTD application, the extensions made by MGI and discuss the strengths and weaknesses of this approach

Does a referral from home to hospital affect satisfaction with childbirth? A cross-national comparison

<p>Abstract</p> <p>Background</p> <p>The Belgian and Dutch societies present many similarities but differ with regard to the organisation of maternity care. The Dutch way of giving birth is well known for its high percentage of home births and its low medical intervention rate. In contrast, home births in Belgium are uncommon and the medical model is taken for granted. Dutch and Belgian maternity care systems are compared with regard to the influence of being referred to specialist care during pregnancy or intrapartum while planning for a home birth. We expect that a referral will result in lower satisfaction with childbirth, especially in Belgium.</p> <p>Methods</p> <p>Two questionnaires were filled out by 605 women, one at 30 weeks of pregnancy and one within the first two weeks after childbirth, either at home or in a hospital. Of these, 563 questionnaires were usable for analysis. Women were invited to participate in the study by independent midwives and obstetricians during antenatal visits in 2004–2005. Satisfaction with childbirth was measured by the Mackey Satisfaction with Childbirth Rating Scale, which takes into account the multidimensional nature of the concept.</p> <p>Results</p> <p>Belgian women are more satisfied than Dutch women and home births are more satisfying than hospital births. Women who are referred to the hospital while planning for a home birth are less satisfied than women who planned to give birth in hospital and did. A referral has a greater negative impact on satisfaction for Dutch women.</p> <p>Conclusion</p> <p>There is no reason to believe Dutch women receive hospital care of lesser quality than Belgian women in case of a referral. Belgian and Dutch attach different meaning to being referred, resulting in a different evaluation of childbirth. In the Dutch maternity care system home births lead to higher satisfaction, but once a referral to the hospital is necessary satisfaction drops and ends up lower than satisfaction with hospital births that were planned in advance. We need to understand more about referral processes and how women experience them.</p

Evidence for the positive-strangeness pentaquark Θ+\Theta^+ in photoproduction with the SAPHIR detector at ELSA

The positive--strangeness baryon resonance $\Theta^+$ is observed in photoproduction of the $\rm nK^+K^0_s$ final state with the SAPHIR detector at the Bonn ELectron Stretcher Accelerator ELSA. It is seen as a peak in the $\rm nK^+$ invariant mass distribution with a $4.8\sigma$ confidence level. We find a mass $\rm M_{\Theta^+} = 1540\pm 4\pm 2$ MeV and an upper limit of the width $\rm \Gamma_{\Theta^+} < 25$ MeV at 90% c.l. From the absence of a signal in the $\rm pK^+$ invariant mass distribution in $\rm\gamma p\to pK^+K^-$ at the expected strength we conclude that the $\Theta^+$ must be isoscalar.Comment: 9 pages, 4 figure