Brane/flux annihilation transitions and nonperturbative moduli stabilization

By extending the calculation of Kahler moduli stabilization to account for an embiggened antibrane, we reevaluate brane/flux annihilation in a warped throat with one stabilized Kahler modulus. We find that depending on the relative size of various fluxes three things can occur: the decay process proceeds unhindered, the anti-D3-branes are forbidden to decay classically, or the entire space decompactifies. Additionally, we show that the Kahler modulus receives a contribution from the collective 3-brane tension. This allows for a significant change in compactified volume during the transition and possibly mitigates some fine tuning otherwise required to achieve large volume.Comment: 25 pages, 6 figures, LaTeX. v2: references adde

Characterisation and application of portable solar absorption spectrometers for the detection of greenhouse gas emissions from regional anthropogenic sources

In der vorliegenden Arbeit wurde im Rahmen des kürzlich vom Karlsruher Institut für Technologie (KIT) etablierten Collaborative Carbon Column Observing Network (COCCON) eine umfassende Kalibrierungsprozedur für ein mobiles Fourier-Transformations-Infrarotspektrometer (EM27/SUN) entwickelt. Zusätzlich wurde die Langzeitstabilität des EM27/SUN untersucht. Zudem wurde ein Ensemble dieser Spektrometer genutzt, um lokale Emissionen starker Emitter der wichtigsten Treibhausgase Kohlenstoffdioxid (CO2) und Methan (CH4) zu quantifizieren. Die Sicherstellung hochgenauer und präziser CO2 und CH4 Messungen ist äußerst wichtig für die Detektion lokaler Quellen dieser Gase. Selbst eine Großstadt bewirkt nur eine Erhöhung der entlang des Sehstrahles gemittelten CO2-Konzentration im Promillebereich über dem atmosphärischen Hintergrund. Verglichen mit der nationalen Skala sind Unsicherheiten von lokalen CO2- und CH4-Emissionen größer. Genaue Messungen von lokalen Quellen, speziell Städten, sind daher wichtig für die Verifizierung von weltweiten Zielen zur Reduktion von Treibhausgasen. Im ersten Teil der Arbeit wurde eine standardisierte Kalibrierungsroutine für EM27/SUN Spektrometer entwickelt. Diese beinhaltet eine Optimierung der optischen Ausrichtung des Spektrometers, Labormessungen für die Charakterisierung der instrumentellen Linienform und atmosphärische Vergleichsmessungen mit einem Referenz-EM27/SUN. Mittels dieser Kalibrierungsprozedur wurden zwischen 2014 und 2018 30 EM27/SUN Spektrometer am KIT justiert und überprüft, was zu sehr einheitlichen Charakteristika der Spektrometer führte. Aufgrund einer engen Zusammenarbeit mit dem Hersteller der EM27/SUN werden neue Spektrometer seit kurzem routinemäßig am KIT überprüft, bevor sie zu Arbeitsgruppen weltweit ausgeliefert werden. In einer dreieinhalbjährigen Studie wurde außerdem die Langzeitstabilität des EM27/SUN gegenüber einem Referenzspektrometer untersucht. Es konnte gezeigt werden, dass das EM27/SUN auf einer Zeitskala von mehreren Jahren stabil ist. Im zweiten Teil dieser Arbeit wurden mehrere EM27/SUN verwendet, um CO2- und CH4-Emissionsstärken von Großstädten zu quantifizieren. In einer ersten Kampagne, durchgeführt in Berlin im Juni und Juli 2014, wurden die Messungen mit einem Dispersionsmodell verglichen. Die beobachteten CO2-Signale sind mit einer Gesamtemissionsstärke der Stadt Berlin von 800 kg CO2 / s verträglich. In einer zweiten Kampagne in Paris im April und Mai 2015 wurde mithilfe der Messungen ein bestehendes Emissionsinventar für den Großraum Paris zusammen mit dem Chemie-Transport-Modell CHIMERE verifiziert. Dabei wurde herausgefunden, dass die Emissionen im Ostteil der Stadt vom Modell unterschätzt werden. Im Gegensatz zu Berlin wurden für Paris außerdem signifikante CH4-Konzentrationsgradienten detektiert. In einer dritten Kampagne, durchgeführt im Großraum Tokyo von Februar bis April 2016, wurden CO2- und CH4-Konzentrationsgradienten gemessen, die deutlich über den für Paris und Berlin ermittelten Werten liegen. Die berechnete CO2-Emissionsstärke zwischen Tokyo und Paris skaliert mit der Einwohnerzahl. Die Ergebnisse dieser Arbeit werden helfen, die Reduktionsziele für Treibhausgase zu überprüfen, wie sie von internationalen Klimakonferenzen, speziell des Pariser COP21 Abkommens, gefordert werden

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

Influence of Novel Space Filling PBF-LB Scanning Strategies on Part Distortion and Density

Additive Manufacturing, especially Powder Bed Fusion – Laser Beam (PBF-LB), is known for its ability to create intricate designs with high precision. Yet, residual stresses remain a challenge, causing distortion. Novel laser paths, including various spiral and space-filling curves such as Hilbert, Gosper, and Peano, have been investigated. They were compared with standard stripe strategies. Parameters such as scan length and hatch distance are varied while maintaining energy density constant. Cantilever beams were used to measure distortion and density. Fractal strategies show minimal distortion with slight density loss. Spiral paths lead to a minimized porosity but show an increased distortion. Segmenting paths reduce distortion across all strategies. The orientation of the cantilever relative to the gas flow affects the distortion extent. Gosper and Hilbert curves reduce distortion with slight density reduction, while spiral paths minimize porosity but increase distortion. Segmenting paths effectively reduce distortion without density loss in all strategies.Mechanical Engineerin

Validation and assessment of satellite-based columnar CO2_2 and CH4_4 mixing ratios from GOSAT and OCO-2 satellites over India

Satellite observations of column-averaged carbon dioxide (XCO$_2$) and methane (XCH$_4$) mixing ratios provide essential data for monitoring greenhouse gas (GHG) emissions. However, the accuracy of emission estimates depends on the precision and bias of satellite retrievals, which require validation against ground-based reference measurements. This study presents a systematic validation of XCO$_2$ and XCH$_4$ data from GOSAT (Greenhouse gases Observing SATellite) and OCO-2 (Oribiting Carbon Observatory-2) satellites over South India using ground-based Fourier transform spectrometer (FTS) observations at Gadanki (13.5 degrees N, 79.2 degrees E) collected from October 2015 to July 2016. Satellite products from National Institute for Environmental Studies, Japan (NIES), NASA\u27s Atmospheric CO$_2$ Observations from Space (ACOS) project, USA (ACOS), and the University of Leicester, UK (UoL) were evaluated using a three-step spatial-temporal pairing method. Results show that the UoL\u27s proxy XCH$_4$ product meets the European Space Agency\u27s Climate Change Initiative (ESA CCI) bias requirement (<10 ppb) across all spatial windows, while the NIES XCH$_4$ product meets the requirement only for intermediate spatial scales. For XCO$_2$, NASA ACOS and OCO-2 products meet the CCI bias requirement (<0.5 ppm), while NIES XCO2 exceeds this threshold. All products satisfy the precision requirement (<8 ppm for XCO$_2$ and <34 ppb for XCH$_4$) with substantial margins. In addition, FLEXPART model simulations using regional emission inventories revealed that agricultural activities dominate seasonal methane enhancements, contributing approximately 55 %, followed by waste and wetland emissions. The model captured seasonal trends but underestimated the amplitude of observed variations, highlighting the influence of changing background methane levels. These findings demonstrate the suitability of recent satellite products for regional GHG monitoring and emphasise the need for expanding ground-based FTS networks across South Asia to support improved emission assessments

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Composite cardiac computed tomography angiography score for improved risk assessment in chronic coronary syndromes

Agatston score, the degree of lumen narrowing categorized by CAD-RADS, high-risk atherosclerotic plaque features and pericoronary adipose tissue attenuation (PCAT) are parameters, which can be assessed non-invasively by coronary computed tomography angiography (CCTA) and aid risk stratification in patients with chronic coronary syndromes (CCS). However, few studies have so far compared the prognostic value of all those parameters together. To develop and test the prognostic value of a composite CCTA score, derived from Agatston score, CAD-RADS, high-risk plaques and PCAT in patients undergoing CCTA due to CCS. Consecutive patients with clinical indication for CCTA and available clinical follow-up of ≥ 6 months after the CCTA examination were included. (i) Agatston score, (ii) CAD-RADS, (iii) the number of plaques with at least one high-risk feature and (iv) PCAT in the proximal 4 cm of the right coronary artery (RCA) were measured, and a composite CCTA score was generated considering all four parameters. The primary endpoint encompassed all-cause mortality, myocardial infarction, and coronary revascularization (> 60 days after the CCTA scan) during follow-up. In total, 759 patients (median age 68.0 (IQR 59.0-76.0) years, 352 (46.4%) female) were included. During a median follow-up of 591.5 (IQR 505.5-686.8) days, 39 (5.1%) patients reached the primary endpoint. Cox-proportional regression demonstrated that the Agatston score, the number of high-risk plaques and CAD-RADS predicted the primary endpoint, independent of age and conventional cardiovascular risk factors. The number of high-risk plaques per patient provided the most robust prediction of the primary endpoint (HR = 2.74, 95%CI = 1.56-4.80, p < 0.001), whereas the composite CCTA score outperformed all other parameters (HR = 1.54, 95%CI = 1.19-1.98, p < 0.001). The Agatston score, CAD-RADS and high-risk plaque features may provide complementary prognostic information in patients with CCS. A composite CCTA score, derived by these imaging markers may identify high-risk individuals, who may benefit from more intensified treatment and clinical follow-up in future studies

Serum concentrations of levosimendan and its metabolites OR-1855 and OR-1896 in cardiac surgery patients with cardiopulmonary bypass

Background: The inotropic drug levosimendan is often used off-label perioperatively in cardiac surgery patients with cardiopulmonary bypass (CPB). Data regarding serum concentrations of levosimendan and its metabolites within this context is lacking. Methods: Total serum concentrations (TSC) and unbound fractions (UF) of levosimendan and its metabolites OR-1896 and OR-1855 in cardiac surgery patients with CPB were retrospectively measured using LC-ESI-MS/MS. Simulation of expected levosimendan TSC was performed using Pharkin 4.0. Serum NT-proBNP was assessed with ELISA. Results: After prolonged levosimendan infusion (1.25 mg or 2.5 mg, respectively) after induction of anaesthesia, a median TSC of 1.9 ng/ml and 10.4 ng/ml was determined in samples taken directly after surgery (T1). Median TSC of 7.6 ng/ml and 22.0 ng/ml, respectively, were simulated at T1. Whereas 1.1 ng/ml and 1.6 ng/ml TSC of OR-1896, respectively, was quantified the day after surgery (T2), TSC of the intermediate metabolite OR-1855 was mostly below the lower limit of quantification (LLOQ). The UF was 0.5% and 1.1% for levosimendan and 64.1% and 52.1% for OR-1896, respectively, with over half the samples being below LLOQ. No difference in NT-proBNP concentrations before surgery and T2 was detected. Discussion: The low TSC, UF and unchanged NT-proBNP levels suggest a need for dose adjustments of levosimendan in this off-label range. In addition, the differences between the measured and estimated concentrations may suggest a possible influence of a CPB on levosimendan serum concentrations. Due to high variation of serum levels between patients, an optimized dosing regimen combined with therapeutic drug monitoring may be advisable