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Personality and motivational incongruence as determinants of the effect of a 6-week high-frequency, standardized sports program (SIWAS study)
No full textThe therapeutic effect of exercise on mental illness has already been shown many times and for patients with various mental illnesses, especially depression (Knapen et al. 2014, Dauwan et al. 2015). However, little research has been conducted into the individual factors that influence the effect or adherence to an exercise program. The aim of this study was to determine whether the personality structure according to the NEO-FFI (Costa & McCrae 1992) or the motivational incongruence with the K-INK (Grawe 2004) influence the effect of a high-frequency 3- to 6-week exercise program, in addition to treatment as usual, in patients with depression (and over 65 years of age), schizophrenia or an addiction disorder. A total of 61 patients were included between November 2021 and July 2022, 26 in the depression group, 22 in the dependence group and 12 in the schizophrenia group.
The statistical analysis showed that there was a significant decrease in motivational incongruence between the examination times, but there were no differences between the groups. There were higher decreases in the patients who showed a more pronounced incongruence at the entry examination. There was also a high correlation between the change in the K-INK and the change in the BDI (r=0.6) and the GAF. However, there was no evidence of a correlation between the extent of motivational incongruence at baseline and the change in the effect parameters. The incongruence at the beginning was not related to a later drop-out, but a higher incongruence was associated with a lower attendance rate of the graduates.
The correlations between the personality dimensions and the change in the effect parameters did not yield any significant results, except that a high level of extraversion and conscientiousness tended to be advantageous. There were also no significant differences between the personality dimensions in the drop-out rate; only the attendance rate of graduates showed medium-strong correlations, with patients with a high openness and low emotional instability showing a higher attendance rate.
Thus, there are indications that motivational incongruence may be suitable as an effect parameter but not as a predictor of the success of a sports therapy program. Although not significant, extraversion and conscientiousness appear to be beneficial for the effect of a sports program. Future studies should re-examine these hypotheses in a randomized, controlled study design and include other effect parameters.2025-02-2
Influence of the hemodynamic subtype of aortic valve stenosis on long-term survival after TAVI
No full textDie kathetergestützte Aortenklappenimplantation (TAVI) ist neben dem chirurgischen Aortenklappenersatz eine etablierte Therapieoption bei hochgradiger symptomatischer Aortenklappenstenose. In dieser Arbeit wurde der Einfluss der hämodynamischen Subtypen der Aortenklappenstenose auf das Langzeitüberleben nach TAVI sowie unabhängige Risikofaktoren für einen ungünstigen Verlauf untersucht.
Methoden: In dieser Studie untersuchten wir die ersten 400 Patienten, die zwischen 08/2008 und 03/2013 in unserer Klinik eine TAVI erhalten haben (203 transapikale und 197 transfemorale Eingriffe, 368 Edwards Sapien- und 32 Medtronic CoreValve-Implantationen). Es erfolgte eine Einteilung in vier Gruppen, entsprechend einer Kombination aus LV-EF, transvalvulärem Flow (P mean) sowie dem Stroke Volume Index (SVI). In 2015/2016 (im Mittel 3 Jahre nach TAVI) wurden alle Patienten telefonisch kontaktiert, um Inzidenz und Ursache der Todesfälle zu erfassen. Die Überlebenszeiten der verschiedenen Subgruppen wurden miteinander verglichen und mittels Kaplan-Meier-Methode analysiert. Des Weiteren wurden Prädiktoren der Langzeitmortalität mittels uni- und multivariater Analyse identifiziert.
Ergebnisse: Das gesamte Kollektiv umfasste 256 Frauen und 144 Männer mit einem Durchschnittsalter von 82 ± 5 Jahren und einem hohen operativen Risiko (mittlerer log. EuroSCORE I 26 ± 15 %). In den vier Subgruppen befanden sich 147 Patienten mit einer NEF - HG AS (LV - EF ≥ 50 %, P mean ≥ 40 mmHg), 63 mit LEF - HG AS (LV - EF < 50 %, P mean ≥ 40 mmHg), 77 mit PLF - LG AS (LV - EF < 50 %, P mean < 40 mmHg, SVI < 35 ml/m²) und 81 mit LEF - LG AS (LV - EF < 50 %, P mean < 40 mmHg).
Im Verlauf einer langen Follow-up Periode von im Mittel drei Jahren (Minimum: bis zum Tode; Maximum: 7,1 Jahre) zeigte die klassische LEF - LG AS ein bemerkenswert schlechtes Langzeitüberleben (LF - LG 1,3 Jahre vs. NEF - NG 5,1 Jahre; P < 0,0001). Das beste Langzeitüberleben von 5,1 Jahren bot die NEF - HG AS. Das Überleben der Patienten mit PLF - LG AS war mit durchschnittlich 3,3 Jahren signifikant schlechter als das derjenigen mit NEF - HG (P = 0,01). In der Gruppe der LEF - HG war das Überleben trotz reduzierter EF nicht signifikant vermindert im Vergleich zur NEF - HG AS (medianes Überleben 4,6 Jahre; P = 0,38).
Das Vorliegen einer LEF - LG Aortenstenose konnte außerdem in der multivariaten Analyse als stärkster Prädiktor bezüglich der Gesamtmortalität (HR 2,86; P = 0,003), der kardiovaskulären Mortalität (HR 6,53; P < 0,0001) und für MACCE (HR 2,44; P = 0,007) bestätigt werden. Bezüglich der echokardiographischen Parameter erwies sich weder der SVI < 35 ml/m² noch die reduzierte EF (letztere mit Ausnahme der Vorhersage Herzinsuffizienz-bedingter Rehospitalisierungen) als unabhängig prädiktiv.
Schlussfolgerungen: Die Langzeitergebnisse, der in den Leitlinien definierten hämodynamischen Subtypen der hochgradigen Aortenklappenstenose, unterscheiden sich signifikant. Das Vorliegen einer schweren Aortenstenose mit niedrigem Gradienten bei beiden Typen (unabhängig von der LV - EF) ist ein Indikator für eine erhöhte Mortalität, während dies bei einer beeinträchtigten LV - EF in Kombination mit hohen Gradienten nicht der Fall ist.Transcatheter aortic valve implantation (TAVI) is an established treatment option alongside surgical aortic valve replacement for severe symptomatic aortic valve stenosis. This study investigated the influence of hemodynamic subtypes of aortic valve stenosis on long - term survival after TAVI and independent risk factors for adverse outcome.
Methods: In this study, we analysed the first 400 patients who underwent TAVI in our clinic between 08/2008 and 03/2013 (203 transapical and 197 transfemoral procedures, 368 Edwards Sapien and 32 Medtronic CoreValve implantations). Patients were divided into four groups according to a combination of LV - EF, transvalvular flow (P mean) and Stroke Volume Index (SVI). In 2015/2016 (an average of 3 years after TAVI), all patients were contacted by telephone to record the incidence and cause of death. Survival was compared between subgroups using the Kaplan - Meier method. Univariate and multivariate analyses were performed to identify predictors of long - term mortality.
Results: The total population included 256 women and 144 men with a mean age of 82 ± 5 years and high surgical risk (mean log EuroSCORE I 26 ± 15 %). The four subgroups included 147 patients with NEF-HG AS (LV - EF ≥ 50 %, P mean ≥ 40 mmHg), 63 with LF-HG AS (LV - EF < 50 %, P mean ≥ 40 mmHg), 77 with PLF-LG AS (LV - EF < 50 %, P mean < 40 mmHg, SVI < 35 ml/m²) and 81 with LEF - LG AS (LV - EF < 50 %, P mean < 40 mmHg).
Over a long follow-up period of three years on average (minimum: until death; maximum: 7.1 years), classic LF - LG AS showed remarkably poor long - term survival (LF - LG 1.3 years vs. NEF - NG 5.1 years; P < 0.0001). NEF - HG AS showed the best long-term survival at 5.1 years. At an average of 3.3 years, the survival of patients with PLF - LG AS was significantly worse than that of patients with NEF - HG (P = 0.01). In the LF - HG group, despite lower EF, survival was not significantly reduced compared to NEF - HG AS (median survival 4.6 years; P = 0.38).
The presence of LF - LG aortic stenosis was also confirmed in multivariate analysis as the strongest predictor of all - cause mortality (HR 2.86; P = 0.003), cardiovascular mortality (HR 6.53; P < 0.0001) and MACCE (HR 2.44; P = 0.007). With regard to echocardiographic parameters, neither SVI < 35 ml/m² nor reduced EF (the latter with the exception of predicting heart failure - related rehospitalizations) proved to be significant.
Conclusions: The long - term outcomes of the guideline - defined hemodynamic subtypes of severe aortic valve stenosis differ significantly. The presence of severe low-gradient aortic stenosis in both types (independent of LV EF) is an indicator of increased mortality, whereas this is not the case for impaired LV - EF in combination with high gradients.2025-03-0
Patienten mit fortgeschrittenen hämatologischen Grunderkrankungen in der Spezialisierten Ambulanten Palliativversorgung (SAPV)
No full textPatients with advanced haematological malignancies in non-curative settings suffer from complex physical symptoms and psychosocial distress, comparable to patients with solid tumour entities. Nevertheless, numerous problems at the interface between haematology and palliative home care have been described. From January 2011 until October 2014, we performed a retrospective, multicenter analysis of all patients with haematological malignancies (ICD 10: C81-C95)
being treated by the respective specialized palliative home care (SAPV) team. Three SAPV teams were surveyed.
Disease entity, physical symptoms, psychosocial distress, number of hospital admissions, therapeutic interventions and
other items were analysed descriptively. Of 3,955 SAPV patients, 1.8% (n = 73) suffered from haematological malignancies.
Main problems were deterioration of general condition, pain or psychological problems. Thirty-seven percent developed
new symptoms during SAPV, mainly pain, psychological distress or deterioration of general status. In 33%, patients
were referred to hospital, mainly due to deterioration of general condition or pain. Seventy percent died within 3 months
after beginning SAPV care; 83% died at home or in a nursing home. Patients suffering from advanced haematological malignancies were statistically underrepresented in SAPV, and SAPV was installed rather at the very last days of life. By
far, more patients were able to die outside a hospital as compared to reference cohorts of haematological patients not being treated in SAPV. The spectrum of documented problems is comparable to other patient cohorts being treated in SAPV; therefore, the options and benefits of palliative home care should be incorporated in palliative haematological treatment concepts more vigorously and consequently.2025-04-2
Functional outcomes after laser microsurgical excision of benign vocal fold lesions
No full textZiel der vorliegenden Studie war es, zu evaluieren, ob die Stimmqualität der Patienten mit benignen Stimmlippenbefunden von einer lasermikrochirurgischen Abtragung profitiert und ob der Laser als sicheres Instrument in der Phonochirurgie angewendet werden kann.
Hierfür wurden in die Untersuchung insgesamt 104 Patienten (33 Männern und 71 Frauen im Alter von 20 bis 82 Jahren) einbezogen. Bei den Patienten wurden insgesamt elf verschiedene, gutartige Befunde der Stimmlippen diagnostiziert. Die Mehrheit der Patienten war Raucher (58 Personen), oder hatten das Rauchen kurz vor Diagnosestellung aufgegeben (7 Personen).
Die operative Abtragung der benignen Stimmlippenveränderungen erfolgte mit Hilfe des CO2-Lasers in Intubationsnarkose.
Die Patientendaten wurden, wie von der European Laryngological Society (ELS) empfohlen, durch verschiedene subjektive und objektive Methoden untersucht:
Die Probanden bewerteten selbstständig ihre Stimmqualität anhand eines Fragebogens, des Voice Handicap Index. Hier konnten sich die Ergebnisse von 37,8 auf 15,9 Punkte verbessern.
Die Stimmqualität wurde mithilfe des Göttinger Heiserkeitsdiagramms, sowie der Stimmfelduntersuchung beurteilt. Hier ergab sich in der Rausch- und Irregularitätskomponente jeweils eine signifikante Steigerung. Außerdem konnten sich die Patienten in den Messungen bezüglich des Intensitätsumfanges, Jitter, DSI und mittlerer Sprechstimmlage steigern.
Außerdem erfolgten eine videolaryngoskopische und -stroboskopische Untersuchung. Diese wurden anhand eines hierfür erstellten Auswertungsbogens bewertet. Es ergab sich eine Verbesserung der Stimmlippenamplitude, sowie eine verbesserte Randkantenverschiebung. Postoperativ zeigte sich weniger Taschenfaltenaktivität und eine weitestgehend glottische Phonation.
Komplikationen waren bei 5 der 104 Patienten nachweisbar, diese ergaben sich ausnahmslos durch Verletzungen bei der Intubation. Rezidive ließen sich bei 9 von 104 Patienten verzeichnen, wobei hier die Mehrzahl Papillome und Reinke-Ödeme vorlagen.
In der Zusammenschau der Ergebnisse konnte in unserer Studie neben der Befundsicherung und –entfernung im Mittel eine Verbesserung der Stimmqualität erreicht werden. Es konnte hiermit gezeigt werden, dass der CO2-Laser als sicheres Instrument in der Phonochirurgie anwendbar ist.The aim of this study was to evaluate whether patients with benign vocal fold lesions benefit from laser micro-surgical excision in terms of voice quality and whether the laser can be used as a safe instrument in phonosurgery.
For this purpose, a total of 104 patients (33 men and 71 women aged between 20 and 82 years) were included in the study. Eleven different benign vocal fold lesions were diagnosed among the patients. The majority of patients were smokers (58 individuals) or had recently quit smoking prior to diagnosis (7 individuals).
The surgical excision of benign vocal fold lesions was performed using a CO2 laser under general anesthesia with intubation.
Patient data were assessed through various subjective and objective methods, as recommended by the European Laryngological Society (ELS):
The participants independently evaluated their voice quality using the Voice Handicap Index questionnaire. The results improved from an average of 37.8 points to 15.9 points.
Voice quality was assessed using the Göttingen Hoarseness Diagram and voice range profile analysis. Both noise and irregularity components showed significant improvements. Additionally, patients demonstrated improvements in measurements such as dynamic range, jitter, DSI, and average speaking pitch.
Video laryngoscopic and stroboscopic examinations were also conducted and assessed using a dedicated evaluation form. Improvements were observed in vocal fold amplitude and mucosal wave propagation. Postoperatively, there was reduced ventricular fold activity and predominantly glottal phonation.
Complications were observed in 5 out of 104 patients, all of which were exclusively due to injuries during intubation. Recurrences were noted in 9 out of 104 patients, with the majority being papillomas and Reinke’s edema.
In summary, our study demonstrated that, in addition to securing and removing the lesions, an overall improvement in voice quality was achieved. Furthermore, it was shown that the CO2 laser is a safe instrument for use in phonosurgery.2025-04-1
From a First Seizure to Chronic Epilepsy – A Structural and Functional Study
No full textCONAHCYTDAADDiagnosing epilepsy after a first unprovoked seizure is challenging, especially in patients
without detectable lesions on standard magnetic resonance imaging (MRI) and without
interictal epileptiform discharges (IEDs) in the electroencephalogram (EEG). In such cases,
more expensive and time-consuming evaluations like sleep-deprived EEG or prolonged
EEG/video-EEG monitoring may be necessary. However, misdiagnosis rates in adults still
range from 5% to 26%, often leading to delayed or inappropriate pharmacological treatment.
This highlights the need for new tools and methods to improve the accuracy and promptness
of epilepsy diagnosis. While functional connectivity (FC) and diffusion tensor imaging (DTI)
have shown promise in identifying patterns across various epilepsy syndromes, research has
predominantly focused on chronic cases. There is a significant lack of studies examining brain
changes associated to a first unprovoked seizure, which is crucial for understanding
epileptogenesis and improving diagnosis and treatment.
This dissertation presents three studies addressing the structural and functional brain
changes that occur in association to a first unprovoked seizure, prior to an epilepsy diagnosis.
Study I retrospectively evaluated source-space low-density EEG-derived metrics—power and
the imaginary part of coherency (ImCoh)—from non-lesional, IED-free, unmedicated patients
after a first unprovoked seizure, comparing them with healthy controls. We further
investigated whether specific differences in these metrics existed between patients who
developed epilepsy and those who remained seizure-free for at least six months.
Study II was a prospective analysis where we employed DTI to determine if patients who
developed epilepsy within a one-year follow-up exhibited distinct patterns of white matter
alterations compared to those who did not. We also evaluated patients with chronic epilepsy.
In Study III, utilizing the same cohort as in Study II, we used source-reconstructed high-density
EEG power and ImCoh to evaluate untreated, non-lesional patients after a first unprovoked
seizure without visible IEDs. We compared those who developed epilepsy to those who did
not and assessed network differences among first-seizure patients, chronic idiopathic
generalized epilepsy (IGE) patients, chronic non-lesional focal epilepsy patients, and healthy
controls.
Overall, this dissertation fills a critical knowledge gap regarding brain changes associated with
a first unprovoked seizure. It provides insights into the early stages of epileptogenesis and
highlights how structural and functional connectivity patterns differ among patients at
various stages of epilepsy, both among themselves and compared to healthy controls. These
findings pave the way for further research into the potential use of brain functional
connectivity and diffusion changes as biomarkers for epilepsy development.2026-01-1
Finite element analysis investigation of positive reduction in the femoral neck fracture
No full textThis work was supported by a scholarship from the China Scholarship Council (No. 202308080019)Aim
Gotfried positive reduction offers an alternative strategy for femoral neck fracture (FNF) when achieving anatomical reduction is challenging. However, quantifying positive reduction and assessing the potential issues from excessive positive reduction remain unclear. The purpose of this study was to investigate the biomechanical behavior of positive reduction across different Pauwels classification, providing a reference for quantifying positive reduction in clinical practice.
Methods
Three-dimensional (3D) models representing negative, anatomical, and positive FNF reductions, each associated with distinct Pauwels groups (Type I, II, and III), were generated based on computed tomography (CT) dataset. These models were stabilized using dynamic hip screws (DHS) and cannulated screws (CS). A 2100 N load was systematically applied to the femoral head, precisely aligned with the mechanical axis of the femur. Our investigation encompassed five parameters, namely the maximum von-Mises stress of internal fixators and the proximal femur, displacement of the proximal femoral head fragment, and displacement of the femur fixed with DHS and CS. Furthermore, we considered the maximum von-Mises strain at the fracture site of the proximal fragment. When evaluating the stability of FNF reduction post-internal fixation, the efficacy of the internal fixation device predominantly influences the stability of the fractured site. In this study, we prioritized the maximum von-Mises stress of the internal fixation as pivotal indicators for assessing the stability across different reduction models.
Results
Within each Pauwels group, the anatomical reduction model exhibited the lowest maximum von-Mises stress on both the internal fixator and proximal femur, and the maximum von-Mises strain at the fracture site of the proximal femur fragment was also lowest in the anatomical reduction model. In the Pauwels I group, positive reduction exceeding 3mm resulted in the maximum von-Mises stress on the internal fixators surpassing that of the negative reduction model. For the Pauwels II group, positive reduction beyond 2mm led to the maximum von-Mises stress on the internal fixators exceeding that of the negative reduction model. In the Pauwels III group, positive reduction beyond 1mm caused the maximum von-Mises stress on the internal fixators to be higher than that of the negative reduction model. The maximum von-Mises stress on the proximal femur increased with positive reduction in Pauwels II and III but decreased in Pauwels I group. The maximum von-Mises strain at the fracture site of proximal femur fragment increased with positive reduction, focusing on the cancellous bone of the CS. Femoral displacement decreased with positive reduction across all Pauwels groups. However, varus displacement increased in positive reduction models as the Pauwels angle rose, potentially exacerbating rotation deformity in Pauwels III.
Conclusions
Excessive positive reduction may increase the risk of FNF failure after internal fixation. From a biomechanical stability perspective, positive reduction should be limited to 3mm or below in the Pauwels I group, restricted to not exceed 2mm in the Pauwels II group, and should not exceed 1mm in the Pauwels III group. Negative reduction should be avoided in all Pauwels groups.2025-03-1
A retrospective analysis of Clostridioides difficile infections from 2016 to the first tertial of 2017 at the geriatric centre of the Evangelisches Krankenhaus Göttingen-Weende
No full textHintergrund: Clostridioides (C.) difficile ist ein häufiger Erreger nosokomialer Infektionen. Ältere Patienten, die eine Antibiotikatherapie erhielten, sind besonders betroffen. Die Inzidenz und der Schweregrad der Infektionen mit C. difficile haben weltweit zugenommen. Ziel dieser Studie war es, patienten- und krankenhausbezogene Faktoren für eine C. difficile-Infektion (CDI) zu identifizieren.
Methoden: Bei CDI-Patienten, die vom 1. Januar 2016 bis zum 30. April 2017 auf den vier geriatrischen Stationen des Evangelischen Krankenhauses Göttingen-Weende (EKW) stationär behandelt wurden, führten wir eine retrospektive Fall-Kontroll-Studie durch. Die Kontrollgruppe bestand aus geriatrischen Patienten desselben Alters und Geschlechts, die im selben Zeitraum stationär aufgenommen wurden. Es gab 62 CDI-Fälle, von denen 6 außerhalb der Geriatrie des EKW erworben wurden. Die Rezidivfälle wurden aus der Analyse ausgeschlossen. Ergebnisse: Die CDI trat häufiger bei Frauen, bei Patienten über 80 Jahren sowie bei Patienten mit Frakturen oder mit Herz/Kreislauf- und Atemwegserkrankungen auf. Zudem zeigte sich, dass Immobilität und eine verminderte Selbstständigkeit bei Alltagsfunktionen (Timed-up-and-Go-Test und Barthel-Index: p=0,01), eine Anämie (p= 0,03) sowie reduzierte Leber- und Nierenfunktionwerte bei der Aufnahme, ein langer Krankenhausaufenthalt (p<0,0001) und die gleichzeitige Einnahme mehrerer Medikamente (p<0,0001) das Risiko erhöhten, eine CDI zu erwerben. Eine vorausgegangene Antibiotikatherapie ( p<0,0001) insbesondere mit (Acyl-) Aminopenicillinen, Cephalosporinen und Makroliden ebenfalls einen Risikofaktor für CDI darstellte. Darüber hinaus wurde die Verteilung der CDI-Fälle auf den vier Stationen des geriatrischen Zentrums des EKW untersucht. Am häufigsten von CDI betroffen waren Patienten, die in der Nähe von Schwesternzimmern untergebracht waren. Infektionen mit C. difficile traten bei Patienten, deren Bettplatz an der Tür oder am Fenster war, gleich häufig auf. Schlussfolgerung: Wir fanden mehrere patienten- und krankenhausbezogene Faktoren, die signifikant mit einer CDI assoziiert waren. Patienten mit einem hohen Risiko, hatten eine hohe Komorbidität und wiesen bereits bei der Aufnahme einen schlechten klinischen Zustand und laborchemischen Veränderungen auf. Insbesondere die Häufung von CDI-Fällen in bestimmten Zimmern und die Polypharmazie als ein Risikofaktor der CDI gaben Anlass, die Hygienemaßnahmen zu intensivieren und die medikamentöse Therapie zu überprüfen, um das Infektionsrisiko zu senken.Background: Clostridioides (C.) difficile is a common pathogen of nosocomial infections. Elderly patients who have received antibiotic therapy are particularly affected. The incidence and severity of C. difficile infections have increased worldwide. The aim of this study was to identify patient- and hospital-related factors for C. difficile infection (CDI).
Methods: We conducted a retrospective case-control study on CDI patients who were hospitalized on the four geriatric wards of the Evangelisches Krankenhaus Göttingen-Weende (EKW) between 1 January 2016 and 30 April 2017. The control group comprised geriatric patients of the same age and gender who were admitted to the EKW during the same period. There were 62 CDI cases, 6 were acquired outside the geriatric department of the EKW. Recurrent cases were excluded from the analysis. Results: CDI occurred more frequently in women, in patients over 80 years old and in those with fractures and with cardiovascular and respiratory diseases. Immobility and reduced independence in daily activities (timed-up-and-go test and Barthel index: p=0.01), anaemia (p=0.03) as well as impaired liver and kidney function values on admission, prolonged hospital stay (p<0.0001) and the simultaneous use of several medications (p<0.0001) also increased the risk of acquiring CDI. Previous antibiotic therapy ( p<0.0001), especially with (acyl-) aminopenicillins, cephalosporins and macrolides, was also a risk factor for CDI.
In this study, the distribution of CDI cases on the four wards of the EKW geriatric centre was also examined. Patients accommodated near nurses' rooms were most frequently affected by CDI. Infections with C. difficile occurred with the same frequency in patients whose bed location was at the door or at the window. Conclusion: Several patient- and hospital-related factors were found to be significantly associated with CDI. High-risk patients were characterised by severe comorbidity, poor clinical condition and laboratory abnormalities upon admission. Specifically, the clustering of CDI cases in some rooms and polypharmacy as a risk factor for CDI were reasons to intensify hygiene measures and to review drug therapy in order to reduce the risk of infection.2025-03-1
Evaluations based on long-term simulations
No full textFederal Ministry of Food and Agriculture (BMEL) [grant number 2818300916]Der künftige Klimawandel wird landwirtschaftliche Bewirtschaftungsstrategien erfordern, die sich an die steigenden Lufttemperaturen und die sich ändernden Niederschlagsmuster anpassen und gleichzeitig Nahrungsmittel, Futtermittel und Biomasse bereitstellt sowie eine Vielzahl von Ökosystemleistungen erhalten. Die Speicherung von atmosphärischem Kohlendioxid in die Atmosphäre als organischer Kohlenstoff (Corg) im Boden ist dabei eine wichtige Maßnahme, um nicht nur die Bodenqualität zu verbessern, sondern auch die mit der landwirtschaftlichen Produktion einhergehenden Emissionen durch beispielsweise Methan oder Lachgas auszugleichen und so die globalen und nationalen klimapolitischen Ziele einzuhalten.
In dieser Dissertation wurden Strategien für eine nachhaltige, klimaangepasste Landnutzung für politische Entscheidungsträger und Landwirte erstellt. Dabei wurden die Auswirkungen einer langfristigen Acker- und Grünlandnutzung auf die chemischen Bodeneigenschaften verglichen, welche die Fähigkeit des Bodens bestimmen, Nährstoffe zu speichern und bereitzustellen, Emissionen von Treibhausgasen (THG) und die Auswaschung von Nährstoffen zu reduzieren, sowie seine Fruchtbarkeit zu verbessern. Im Rahmen einer Literaturrecherche wurden mehrere Bewirtschaftungspraktiken zur Verbesserung dieser Eigenschaften identifiziert, wie die Einführung einer artenreichen Dauervegetation, der Anbau von Leguminosen und Zwischenfrüchten, die Einführung von Grünlandphasen in einer Ackerfruchtfolge, die Verringerung der Bodenbearbeitung auf Ackerland, die Bevorzugung der Beweidung gegenüber dem Mähen von Grünland, und die Erhöhung des Eintrags organischer Stoffe, z. B. durch die Rückhaltung von Ernterückständen oder den verstärkten Einsatz organischer Düngemittel.
Um das Potenzial der Corg-Speicherung sowohl auf nationaler als auch auf regionaler Ebene zu prüfen, wurden Simulationen mit dem CANDY-Modell durchgeführt, bei denen insgesamt 18 Szenarien des künftigen Klimawandels bis zum Jahr 2100 sowie unterschiedliche Bewirtschaftungssysteme an mehreren repräsentativen Standorten angewendet wurden. Bei den Simulationen auf nationaler Ebene wurden Regionen mit hoher Priorität identifiziert, die entweder ein hohes Risiko für Corg-Verluste bei suboptimaler Bewirtschaftung oder ein Potenzial für hohe Corg-Gewinne aufweisen, was als Leitfaden für künftige Entscheidungen in der Umweltpolitik dienen kann. Besonders sandige oder schluffige Standorte mit geringen Sommerniederschlägen sind einem hohen Risiko von Corg-Verlusten ausgesetzt. Im Gegensatz dazu werden vor allem Standorte in Mittelgebirgs- bis Alpenregionen vom zukünftigen Klimawandel und den damit zu erwartenden steigenden Lufttemperaturen profitieren, da erwartungsgemäß in solchen Regionen selbst unter den extremsten Klimaszenarien kein Trockenstress auftreten wird. Die dadurch verlängerte Dauer der Vegetationsperiode wird das Pflanzenwachstum und die Rhizodepisition fördern. Das Corg-Bindungspotenzial ist auf tonreichen Böden, sowohl auf regionaler als auch nationaler Betrachtung, bei intensiver Bewirtschaftung, insbesondere bei Beweidung, am höchsten. Intensives Grünland auf tonreichen Böden birgt den Simulationen zufolge jedoch auch das höchste Risiko von Corg-Verlusten durch Bodenverdichtung und ist damit ein Standort mit hoher Priorität. Ferner kann unter steigender Intensivierung ein Rückgang des Artenreichtums einhergehen, welches wiederum in vielen Regionen eine hohe Priorität genießt und darüber hinaus sowohl zur Verbesserung der Bodenqualität als auch Corg-Speicherung beiträgt. Daher stellen die hier gewonnenen Erkenntnisse einen groben Leitfaden dar, wobei konkrete Empfehlungen der Bewirtschaftungsintensität stets unter Berücksichtigung potenzieller Kompromisse auf standortebene auszusprechen sind.Future climate change will require agricultural management to adapt to increasing air temperatures and changing precipitation patterns while simultaneously providing food, fodder and biomass, and maintaining a variety of ecosystem services. The sequestration of atmospheric carbon dioxide into the atmosphere as soil organic carbon (SOC) is thereby a key measure not only in improving the soil quality but also to counterbalance emissions of e.g. methane or nitrous oxide associated with agricultural production, thereby adhering to global and national climate policy goals.
This thesis provides a guideline for sustainable land use for policy-makers and farmers by comparing the impact of long-term arable and grassland use on the chemical soil properties, which determine the soil’s ability to store and provide nutriens, limit emissions of greenhouse gases (GHG) and leaching of nutrients, as well as its overall fertility. As part of a review, several management practices aimed at improving these properties were identified, e.g. introduction of a biodiverse, permanent vegetation, growing legumes and catch crops, implementing grassland phases in an arable rotation, reduction of tillage on arable land, prefering grazing over mowing on grassland, and increasing inputs of organic matter by e.g. retaining harvest residues or increasing inputs of organic fertilisers.
In order to explore the SOC sequestration potential on a national and regional scale, simulations using the CANDY model were performed by applying 18 future climate change scenarios until the year 2100 and contrasting management regimes on several representative sites. The simulations identified regions of high priority due to either high risks for SOC losses under suboptimal management or a potential for high SOC gains, which may guide future decision-making in environmental policies. Particularly sandy or silty sites with low summer precipitation are at high risk of SOC losses. In contrast, particularly sites in low-mountainous to alpine regions will benefit from future climate change and therewith expected increasing air temperatures due to no dryness stress occuring in such regions even under the most extreme climate scenarios. The therereby extended duration of the vegetation period will promote plant growth and rhizodepisition. The SOC sequestration potential on both the national and regional scale is highest on clay-rich soils under intensive, particularly grazing, management. However, intensive grasslands on clay-rich soils also have the highest risk of SOC losses as a result of soil compaction according to the simulations, rendering them sites of high priority. Furthermore, high intensification can be accompanied by a decline in biodiversity, which in turn is a high priority in many regions and also contributes to improving both soil quality and SOC storage. The findings of this thesis therefore represent a rough guideline, whereby specific recommendations for management intensity must always be made taking into account potential trade offs at site level.2025-07-0
Landscape Moderation of Ecological Patterns and Processes
Get PDFThis dissertation studies landscape moderation of ecological patterns and processes by employing different modeling approaches to investigate how landscape patterns influence ecological processes and, reversely, how ecological processes form landscape patterns.
The research presented in this dissertation combines two powerful modeling frameworks: pattern-oriented modeling and individual-based modeling. Pattern-oriented modeling integrates empirical data with theory to enhance predictive accuracy, while individual-based modeling simulates patterns emerging from the behavior and interactions of individual organisms within their ecosystems.
The dissertation is structured into three main chapters, each targeting a distinct question on the relationship between landscape patterns and ecological processes:
In the first study, we investigated the relative effects of habitat amount and fragmentation on species population sizes using the MOBILE simulation model. We model the species’ population sizes because the population dynamics allow us to infer possible threats to biodiversity over time, such as an extinction debt due to small population sizes. We simulated 17 modeled ground beetle species on 600 artificial landscapes to disentangle the independent effects of fragmentation and habitat amount. Our results showed an independent negative effect of fragmentation on the simulated populations, but the effect was smaller than that of habitat loss. The relative effect of fragmentation on the population size was stronger for smaller amounts of habitat and species-specific. We also found that species with higher dispersal abilities were less affected by fragmentation in our model. Our study demonstrates the utility of simulation models for analyzing the complex relationships between species and their landscape context.
The second study introduced the FACIA model, which we used to simulate spatial vegetation self-organization and showed how can lead to fairy circles, i.e. to circular barren patches that are regularly distributed in space in a hexagonal pattern. FACIA models only two mechanisms, local facilitation and non-local competition, which generate the emergent patterns of fairy circles. The FACIA model successfully replicated the characteristic spatial patterns of fairy circles. Further simulation experiments showed that self-organization can reproduce the deformed fairy circle patterns found under local disturbance by car tracks. With a combination of simplicity and structural realism, we demonstrated with FACIA how combining individual-based and pattern-oriented modeling leads to a deeper understanding of how small-scale processes can lead to landscape-scale patterns.
In the third study, we developed the R package spectre, which uses minimal biological data to estimate regional community compositions at fine spatial resolutions. Based on an optimization algorithm and α-, β-, and γ-diversity estimates from scarcely sampled field data, spectre can predict realistic species presences and absences at hundreds of unsampled sites in a landscape. In ecological modeling, spectre may become especially useful to realistically initialize simulation models when field data with α-, β- and γ-diversity is available. In this application, spectre would be used to apply the same diversity functions on different artificial landscapes, and the resulting spatially explicit biodiversity patterns could then be used as an input to simulation experiments.
All three studies emphasize the advantages of integrating models with empirical data, thereby facilitating a more comprehensive understanding of ecological dynamics and ultimately informing and even enabling effective conservation strategies. Our findings advance ecological theory while at the same time providing practical insights for managing and preserving biodiversity in a changing world.
The dissertation concludes with a general discussion integrating findings from all three studies. It emphasizes the necessity of combining theoretical approaches with computational tools for investigating complex ecological phenomena. In modeling beetle populations, simulating the formation of fairy circles, and developing the spectre R package, we demonstrated the significance of addressing species-specific responses to habitat fragmentation, understanding the mechanisms of landscape pattern formation, and developing computational tools to enhance biodiversity research in order to ultimately support the sustainable management of biodiversity in changing landscapes.2025-03-0
Effects of iliosacral joint immobilization on walking after iliosacral screw fixation in humans
No full textBeckenringfrakturen stellen aufgrund der Verletzungsschwere einen hohen Anspruch an die Versorgung. Besondere Bedeutung kommt den Typ-B- und Typ-C-Verletzungen zu, die häufig durch ein Hochrasanztrauma entstehen und zu einer Instabilität des Beckenrings führen. Üblicherweise wird diese Instabilität operativ mittels der perkutanen Schraubenosteosynthese stabilisiert. Hierbei führt die implantierte Schraube zwischen Sakrum und Ilium zu einer Fixierung des ISG.
Ziel dieser Arbeit war es, die Auswirkungen einer iliosakralen Fixierung auf den Gang zu untersuchen. Dazu wurden in einem Ganglabor mittels einer dreidimensionalen Ganganalyse die allgemeinen Gangparameter sowie kinematischen und kinetischen Daten einer Patienten- und Kontrollgruppe gemessen. Mittels der Simulationssoftware OpenSim wurde ein muskuloskelettales Modell skaliert und die gemessenen Daten weiterverarbeitet, um die Kinematik und Kinetik der Gelenke zu berechnen.
Insgesamt ähnelte das Gangbild der Patientengruppe, dem der Kontrollgruppe. Für den Großteil der Gelenkparameter zeigte sich keine Signifikanz zwischen den Probandengruppen. Es konnten jedoch signifikante Gruppenunterschiede für das Moment und die Leistung der Plantarflexoren beim „Überqueren einer Stufe“ festgestellt werden. Die Patientengruppe wies ein geringeres Plantarflexormoment und eine geringere Plantarflexorleistung als die Kontrollgruppe auf. Diese Gruppenunterschiede waren bei der Versuchsaufgabe „Ebenerdiges Gehen“ bereits sichtbar, wurden durch die anspruchsvollere Versuchsaufgabe „Überqueren einer Stufe“ jedoch deutlicher hervorgehoben. Patienten zeigen nach iliosakraler Fixierung eine signifikante Einschränkung der Bewegung auf.Pelvic ring fractures place high demands on treatment due to the severity of the injury. Type B and type C injuries, which are often caused by high-impact trauma and lead to instability of the pelvic ring, are particularly important. This instability is usually stabilized by surgical implants. However, such implants immobilize the iliosacral joint. The aim of this study was to investigate the effects of iliosacral fixation on gait. For this purpose, the general gait parameters as well as kinematic and kinetic data of a patient and control group were measured in a gait laboratory using a three-dimensional gait analysis. Using the OpenSim simulation software, a musculoskeletal model was scaled and the measured data further processed in order to calculate the kinematics and kinetics of the joints.
Overall, the gait pattern of the patient group was similar to that of the control group. There was no significance between the subject groups for the majority of joint parameters. However, significant group differences were found for the moment and power of the plantar flexors when “crossing a step”. The patient group showed a lower plantar flexor moment and a lower plantar flexor power than the control group. These group differences were already visible in the “walking on level ground” test task, but were more clearly emphasized by the more demanding “crossing a step” test task. Patients show a significant restriction of movement after iliosacral fixation.2025-04-2