In-hospital Delay Increases the Risk of Perforation in Adults with Appendicitis

Background: The influence of in-hospital delay (time between admission and operation) on outcome after appendectomy is controversial. Methods: A total of 1,827 adult patients underwent open or laparoscopic appendectomy for suspected appendicitis in eleven Swiss hospitals between 2003 and 2006. Of these, 1,675 patients with confirmed appendicitis were included in the study. Groups were defined according in-hospital delay (≤12 vs. >12h). Results: Delay>12h was associated with a significantly higher frequency of perforated appendicitis (29.7 vs. 22.7%; P=0.010) whereas a delay of 6 or 9h was not. Size of institution, time of admission, and surgical technique (laparoscopic vs. open) were independent factors influencing in-hospital delay. Admission during regular hours was associated with higher age, higher frequency of co-morbidity, and higher perforation rate compared to admission after hours. The logistic regression identified four independent factors associated with an increased perforation rate: age (≤65years vs. >65years, odds ratio (OR) 4.5, P0 vs. Charlson index=0, OR 2.3, P12 vs. ≤12h, OR 1.5, P=0.005). Perforation was associated with an increased reintervention rate (13.4 vs. 1.6%; P<0.001) and longer length of hospital stay (9.5 vs. 4.4days; P<0.001). Conclusions: In-hospital delay negatively influences outcome after appendectomy. In-hospital delay of more than 12h, age over 65years, time of admission during regular hours, and the presence of co-morbidity are all independent risk factors for perforation. Perforation was associated with a higher reintervention rate and increased length of hospital sta

Understanding low-level clouds in western Equatorial Africa during the long dry season

Die Dissertation zeigt anhand von verschiedenen Beobachtungsdaten und numerischen Wettervorhersagemodellen die Ursachen für die Entstehung und Auflösung niedriger Wolken im westlichen Äquatorialafrika während der langen Trockenzeit von Juni bis September. Tiefe Wolken spielen eine wichtige Rolle bei der Erhaltung des Regenwaldes und im Strahlungshaushalt der Erde. Sie werden jedoch in Wetter- und Klimamodellen nicht korrekt repräsentiert, was zu Ungenauigkeiten in Berechnungen führt, die auf korrekteren Strahlungsbudgets basieren, wie z.B. Projektionen des Klimawandels. Niedrige Wolken haben je nach Perspektive unterschiedliche phänotypische Eigenschaften, die in dieser Dissertation untersucht werden. Mit Hilfe von Stationsdaten und Satellitendaten konnte der unterschiedliche Tagesgang der Wolken zwischen der küstennahen Region, in der die tiefen Wolken ein morgendliches Aufbrechen zeigen, der windzugewandten Seite der Chaillu Berge, wo sich eine Staulage ohne Aufklarung bildet, und dem östlichen Teil Gabuns, der durch eine große Amplitude der tiefen Wolken im Tagesgang gekennzeichnet ist, gebildet werden. Die Stationsdaten zeigen zudem einen Übergang von Cumulus zu Stratocumulus im Tagesverlauf, was auf eine durch Konvektion aufgebrochene Wolkendecke hindeutet. Über dem Nordosten der Republik Kongo sind ebenfalls mesoskalige konvektive Systeme zu erkennen, die sich in Richtung Nordwesten bewegen und dementsprechend im Nordosten von Gabun Regenschauer bringen können. Darüber hinaus verringern diese Wolken und die Wolkenausläufer die Genauigkeit der Erkennung niedriger Wolken aus dem Weltraum, da sie die Wolken verdecken. Das Produkt 2B-Geoprof-LiDAR, das auf den sonnensynchronen, erdumfliegenden Satelliten CALIPSO und CloudSat basiert, lieferte außerdem Informationen über die vertikale Verteilung von Wolken in verschiedenen Regionen im westlichen Äquatorialafrika. Ein Hauptunterschied zwischen Ozean und Land ist die sehr stratiforme Wolkenschicht über dem Wasser, die über Land vertikal viel stärker perturbiert wird, einerseits durch die rauere Oberfläche und andererseits durch die stärkere Konvektion tagsüber über Land. Bei der Verwendung des numerischen Wettervorhersagemodells ICON gibt es auffällige Unterschiede in Temperatur, Feuchte, Wind und Stabilität zwischen expliziter und parametrisierter Konvektion. Die Parametrisierung der hochreichenden Konvektion führt zu einer Austrocknung der Atmosphäre an den Grenzen der innersten Domain durch konvektiven Niederschlag. In der parameterisierten Version wird ein entsprechend niedriger Feuchtegehalt in die Modelldomain transportiert, wie anhand von des Feuchtebudgets an den Domaingrenzen gezeigt wird. Dies ist erkennbar an der geringeren Anzahl von tiefen Wolken und dem reduzierten Niederschlag im westlichen Äquatorial Afrika. Die Parameterisierung der flachen Konvektion führt zu einer Austrocknung der unteren Troposphäre und einer Feuchtigkeitsanhäufung im Übergang von der unteren zur mittleren Troposphäre im Vergleich zur Simulation ohne parametrisierte Konvektion. Das Parameterisierungsschema hebt die Grenzschicht an, was zu einer niedrigeren spezifischen Feuchte in der feuchten Mischungsschicht führt, die im expliziten Lauf weiter in die trockenere mittlere Troposphäre reicht. Mithilfe der Froude-Zahl, die einen Stabilisierungsindikator darstellt, kann gezeigt werden, dass die Chaillu Berge in der Nacht umströmt werden, was bereits in historischen Beobachtungen aufgezeichnet wurde

Isotopic Composition of Solar Wind Calcium: First in Situ Measurement by CELIAS/MTOF on Board SOHO

We present first results on the Ca isotopic abundances derived from the high resolution Mass Time-of-Flight (MTOF) spectrometer of the charge, element, and isotope analysis system (CELIAS) experiment on board the Solar and Heliospheric Observatory (SOHO). We obtain isotopic ratios 40Ca/42Ca = (128+-47) and 40Ca/44Ca = (50+-8), consistent with terrestrial values. This is the first in situ determination of the solar wind calcium isotopic composition and is important for studies of stellar modeling and solar system formation since the present-day solar Ca isotopic abundances are unchanged from their original isotopic composition in the solar nebula.Comment: 14 pages, 3 figure

A Simple, Automatic Means of Designing a Conversion Table for Expressing Laboratory Results in the International System of Units (SI)

Peer Reviewe

Understanding Selective Oxidations

Functionalizing organic molecules is an important value-creating step throughout the entire chemical value-chain. Oxyfunctionalization of value-chain. Oxyfunctionalization of e.g. C–H or C=C bonds is one of the most important functionalization technologies used industrially. The major challenge in this field is the prevention of side reactions and/or the consecutive over-oxidation of the desired products. Despite its importance, a fundamental understanding of the intrinsic chemistry, and the subsequent design of a tailored engineering environment, is often missing. Industrial oxidation processes are indeed to a large extent based on empirical know-how. In this mini-review, we summarize some of our previous work to help to bridge this knowledge gap and elaborate on our ongoing research

Tracing attacks and restoring integrity with LASCAR

We present a novel method to trace the propagation of intrusions or malicious code in networked systems. Our solution is aimed at large numbers of loosely managed workstations typical of a research environment as found in CERN. The system tags events which have a potential to become harmful. On a given machine all processes that results from the tagged event are marked with the same tag and the tag is carried on to others machines if a tagged process establishes a connection. Tag creation logs are stored in a central database. When an intrusion is detected at a later time, all machines and processes that may have lost their integrity due to this incident can easily be found. This leads to a quick and effective restoration of the system. Our implementation of the system is designed to incur very little overhead on the machines and integrates easily with many flavors of the Linux operating system on any type of hardware

Diurnal to interannual variability of low‐level cloud cover over western equatorial Africa in May–October

This study examines the diurnal to interannual variations of the stratiform cloud cover in May–October (1971–2019) from a 3-hourly station database and from ERA5 reanalyses over western equatorial Africa (WEA). The main diurnal variations of the local-scale fraction and genus of stratiform clouds are synthesized into three canonical diurnal types (i.e., “clear,” “clear afternoon,” “cloudy” days). The interannual variations of frequencies of the three diurnal types during the cloudiest months (JJAS) are mostly associated with two main mechanisms: a meridional shallow overturning cell associating more “cloudy” and less “clear” and “clear afternoon” days to anomalous southerlies below 900 hPa over and around WEA, anomalous ascent around 5°–7°N, anomalous northerlies between 875 and 700 hPa, and anomalous subsidence over the equatorial Atlantic. This circulation is strongly related to interannual variations of the equatorial Atlantic upwelling (i.e., more clouds when the upwelling is strong) associated with a meridional shift of the Intertropical Convergence Zone over the Tropical Atlantic and adjacent continents. The second mechanism operates mostly in the zonal direction and involves again the coupled ocean–atmosphere system over the equatorial Atlantic, but also the remote El Niño–Southern Oscillation (ENSO). An anomalously cold equatorial Atlantic drives increased low-level westerlies toward the Congo Basin. Warm ENSO events promote broad warm and easterly anomalies in the middle and upper troposphere, which increase the local static stability, and thus the local stratiform cloud cover over WEA. The present study suggests new mechanisms responsible for interannual variations of stratiform clouds in WEA, thus providing avenues of future research regarding the stability of the stratiform cloud deck under the ongoing differential warming of tropical ocean and land masses

Exploring hail and lightning diagnostics over the Alpine-Adriatic region in a km-scale climate model

The north and south of the Alps, as well as the eastern shores of the Adriatic Sea, are hot spots of severe convective storms, including hail and lightning associated with deep convection. With advancements in computing power, it has become feasible to simulate deep convection explicitly in climate models by decreasing the horizontal grid spacing to less than 4 km. These kilometer-scale models improve the representation of orography and reduce uncertainties associated with the use of deep convection parameterizations. In this study, we perform km-scale simulations for eight observed cases of severe convective storms (seven with and one without observed hail) over the Alpine-Adriatic region. The simulations are performed with the climate version of the regional model Consortium for Small-scale Modeling (COSMO) that runs on graphics processing units (GPUs) at a horizontal grid spacing of 2.2 km. To analyze hail and lightning we have explored the hail growth model (HAILCAST) and lightning potential index (LPI) diagnostics integrated with the COSMO-crCLIM model. Comparison with available high-resolution observations reveals good performance of the model in simulating total precipitation, hail, and lightning. By performing a detailed analysis of three of the case studies, we identified the importance of significant meteorological factors for heavy thunderstorms that were reproduced by the model. Among these are the moist unstable boundary layer and dry mid-level air, the topographic barrier, as well as an approaching upper-level trough and cold front. Although COSMO HAILCAST tends to underestimate the hail size on the ground, the results indicate that both HAILCAST and LPI are promising candidates for future climate research.</p

Halogen activation and radical cycling initiated by imidazole-2-carboxaldehyde photochemistry

Atmospheric aerosol particles can contain light-absorbing organic compounds, also referred to as brown carbon (BrC). The ocean surface and sea spray aerosol particles can also contain light-absorbing organic species referred to as chromophoric dissolved organic matter (CDOM). Many BrC and CDOM species can contain carbonyls, dicarbonyls or aromatic carbonyls such as imidazole-2-carboxaldehyde (IC), which may act as photosensitizers because they form triplet excited states upon UV&ndash;VIS light absorption. These triplet excited states are strong oxidants and may initiate catalytic radical reaction cycles within and at the surface of atmospheric aerosol particles, thereby increasing the production of condensed-phase reactive oxygen species (ROS). Triplet states or ROS can also react with halides, generating halogen radicals and molecular halogen compounds. In particular, molecular halogens can be released into the gas phase, which is one halogen activation pathway. In this work, we studied the influence of bromide and iodide on the photosensitized production and release of hydroperoxy radicals (HO2) upon UV irradiation of films in a coated wall flow tube (CWFT) containing IC in a matrix of citric acid (CA) irradiated with UV light. In addition, we measured the iodine release upon irradiation of IC ∕ CA films in the CWFT. We developed a kinetic model coupling photosensitized CA oxidation with condensed-phase halogen chemistry to support data analysis and assessment of atmospheric implications in terms of HO2 production and halogen release in sea spray particles. As indicated by the experimental results and confirmed by the model, significant recycling of halogen species occurred via scavenging reactions with HO2. These prevented the full and immediate release of the molecular halogen (bromine and iodine) produced. Recycling was stronger at low relative humidity, attributed to diffusion limitations. Our findings also show that the HO2 production from BrC or CDOM photosensitized reactions can increase due to the presence of halides, leading to high HO2 turnover, in spite of low release due to the scavenging reactions. We estimated the iodine production within sea salt aerosol particles due to iodide oxidation by ozone (O3) at 5.0&times;10-6 M s&minus;1 assuming O3 was in Henry's law equilibrium with the particle. However, using an O3 diffusion coefficient of 1&times;10-12 cm2 s&minus;1, iodine activation in an aged, organic-rich sea spray is estimated to be 5.5&times;10-8 M s&minus;1. The estimated iodine production from BrC photochemistry based on the results reported here amounts to 4.1&times;10-7 M s&minus;1 and indicates that BrC photochemistry can exceed O3 reactive uptake in controlling the rates of iodine activation from sea spray particles under dry or cold conditions where diffusion is slow within particles.</p