Use of severity classification systems in the surgical decision-making process in emergency laparotomy for perforated diverticulitis

Purpose: Hartman's procedure (HP) or primary anastomosis (PA) are the two surgical techniques used in patients undergoing emergency colectomy for perforated diverticulitis. There are no objective criteria to guide the surgeon's choice of procedure. This study assesses whether classification and scoring systems can be used in the decision-making process. Methods: One hundred eleven patients undergoing emergency laparotomy for perforated diverticulitis were analyzed. Logistic regression and interaction models were used to determine the predictive value in the two settings. Results: Sixty five patients underwent HP and 46 patients underwent PA. Patients with HP had significantly higher scores, median age, and were more often on immunosuppressive medication. Mortality and surgical morbidity did not differ between the groups. The clinical anastomotic leak rate was 28.3% in the PA group. In the univariate logistic regression for in-hospital death, all scores showed a significant influence. The multivariate logistic regression analysis showed that only Charlson comorbidity index (CCI) and American Society of Anesthesiologists score had a significant influence on mortality. Each score was analyzed for its predictive value regarding mortality and morbidity with respect to type of operative procedure. Only CCI revealed a trend towards statistical significance. The risk of death increases with increasing CCI when PA is performed compared to HP. Conclusion: None of the tested scores can be used to help the surgeon decide whether a PA or HP is appropriate in a specific patient. Comorbidity, represented as CCI in this study, might be more important than the locoregional situatio

Environmental heterogeneity affects input, storage, and transformation of coarse particulate organic matter in a floodplain mosaic

Quantifying spatial and temporal dynamics of organic matter (OM) is critical both for understanding ecosystem functioning and for predicting impacts of landscape change. To determine the influence of different habitats and coarse particulate OM (CPOM) types upon floodplain OM dynamics, we quantified aerial input, lateral surface transfer, and surface storage of CPOM over an annual cycle on the near-natural floodplain of the River Tagliamento in NE-Italy. Using these data, we modelled floodplain leaf dynamics, taking account of the spatial distribution and hydrologic connectivity of habitats, and using leaf storage as a response variable. Mean aerial CPOM input to the floodplain was similar from riparian forest and islands, but surface transfer was greater from islands, supporting the suggestion that these habitats act as "islands of fertility” along braided rivers. Leaves were the lateral conveyor of energy to more open parts of the floodplain, whereas CPOM was mainly stored as small wood in vegetated islands and riparian forest. Simulating the loss of habitat diversity (islands, ponds) decreased leaf storage on the whole floodplain, on exposed gravel and in large wood accumulations. In contrast, damming (loss of islands, ponds and floods plus floodplain overgrowth) greatly increased storage on exposed gravel. A random shuffle of habitats led to a storage increase on exposed gravel, while that in large wood accumulations and ponds declined. These results disentangle some of the complexities of CPOM dynamics in floodplain ecosystems, illustrate the value of models in understanding ecosystem functioning at a landscape level, and directly inform river management practic

Supercell thunderstorms in complex topography - how lakes in mountain valleys can increase occurrence frequency

While supercell thunderstorms are one of the most severe convective phenomena, their behavior in complex terrain is still poorly understood. Observational studies in the Southern Alps have revealed local supercell "hotspots" associated with valleys with large lakes. With a newly developed radar-based, mesocyclone-detection algorithm, the occurrence and evolution of supercell thunderstorms in the Alpine region were characterized. That study highlights the influence of orography on both storm intensity and occurrence frequency. To disentangle the different influential factors, an idealized modeling framework is established using the mesoscale model CM1. In different modeling experiments the key characteristics of this region have been generalized. The modeling scenarios are based on a high-CAPE environment with unidirectional shear, where a warm bubble serves to initiate the convection. Mimicking the environment of the southern Prealps in central Europe, scenarios with a high mountain ridge, valleys and lakes are explored. Varying both the topographic features and the initial conditions permits the investigation of the individual impact of slopes, valleys and moisture sources. The dynamic and thermodynamic impact of mountain valleys with lakes increases the range of atmospheric conditions that supports supercellular development through horizontal vorticity production and maintenance of high equivalent potential temperature. This influence results in a systematic location dependence of the frequency, intensity and lifetime of supercells, as also found in observations

Understanding Producers’ Perspectives on Rotational Grazing Benefits Across US Great Plains

Experimental findings on rotational grazing (RG) trials have generally differed from producer observations of RG outcomes on commercial scale ranches. Factors such as small plot size, short duration trials and relatively rigid grazing management that lacks responsiveness to the dynamic and complex social-ecological systems in grazing trials could all contribute to this disparity in outcomes. These differences call for a better understanding of producer perceptions of RG benefits. To fill this knowledge gap, we surveyed 4500 producers from the Northern and Southern Great Plains of the USA. Among the 875 respondents, 40.5% reported that they used continuous grazing (CG), 52.7% implemented RG management in an extensive manner, while 6.8% adopted management intensive grazing. Compared with CG users, adopters of RG in its extensive and intensive form reported an average annual increase of grazing season by 7.6 and 39.3 days, respectively. When controlling for producer demographics, ranch management goals and other rancher characteristics, we found soil and climate heterogeneity significantly affected the perceived relative benefits of RG vs CG strategies. Therefore, instead of focusing on whether RG outperforms CG per se, future research could focus on comparison of RG benefits under different management intensity levels and identifying soil and climate conditions where RG benefits are more noticeable

A robust digital method for film contrast correction in subtraction radiography

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66366/1/j.1600-0765.1986.tb01484.x.pd

CCM – IAG Strategy for Metrology in Absolute Gravimetry: Role of CCM and IAG

The President of the Consultative Committee for Mass and related quantities (CCM) and the President of the International Association of Geodesy (IAG) Commission 2 «Gravity Field» met on March 21, 2013 with the objective to better coordinate the work at the level of both organizations. It was decided to prepare a common strategic document to be used by their respective Working Groups (WG), Sub-commission (SC) and Joint Working Groups (JWG) to clarify future activities and to develop an action plan.The main objective is to define and to harmonize the activities in order to ensure traceability to the SI for gravity measurements at the highest level for metrology and geodesy with-in the framework of the CIPM Mutual Recognition Arrangement (CIPM MRA

Pathways of Understanding: the Interactions of Humanity and Global Environmental Change

How humans, interacting within social systems, affect and are affected by global change is explored. Recognizing the impact human activities have on the environment and responding to the need to document the interactions among human activities, the Consortium for International Earth Science Information Network (CIESIN) commissioned a group of 12 scientists to develop a framework illustrating the key human systems that contribute to global change. This framework, called the Social Process Diagram, will help natural and social scientists, educators, resource managers and policy makers envision and analyze how human systems interact among themselves and with the natural system. The Social Process Diagram consists of the following blocks that constitute the Diagram's structural framework: (1) fund of knowledge and experience; (2) preferences and expectations; (3) factors of production and technology; (4) population and social structure; (5) economic systems; (6) political systems and institutions; and (7) global scale environmental processes. To demonstrate potential ways the Diagram can be used, this document includes 3 hypothetical scenarios of global change issues: global warming and sea level rise; the environmental impact of human population migration; and energy and the environment. These scenarios demonstrate the Diagram's usefulness for visualizing specific processes that might be studied to evaluate a particular global change issues. The scenario also shows that interesting and unanticipated questions may emerge as links are explored between categories on the Diagram

Grand challenges for aerosol science and technology

The Grand Challenges Workshop for Aerosol Science and Technology was organized for the International Aerosol Conference (IAC), in St Louis, September 2–7, 2018. The purpose of the workshop was to identify “Grand Challenges” for aerosol science and technology in the next decade and thereby indicate a viable research road map for the aerosol community

The temporal evolution of the Mitu group, south-east Peru – first U-Pb age data

The Eastern Cordillera of southern Peru formed along a crustal zone that has been active as part of the western Gondwana margin since the middle Paleozoic. The present study investigates the Mitu Group of south-east Peru in the area of Abancay-Cusco-Sicuani-Titicaca. This unit comprises continental clastic sediments deposited in syn-sedimentary basins during an extensional period in Permo-Triassic times and has not benefitted from a thorough geochemical-geochronological investigation so far. One of the main reasons for this lack of data is a complex structure of the graben system, tectonically complicated by compressional inversion of the extensional basins during Andean orogeny. Due to dominating coarse-grained clastics, the Mitu Group is devoid of fossils and its age is only poorly bracketed to be Permo -Triassic based on its stratigraphic relation to the underlying Copacabana and overlying Pucara groups. The upper levels of the Copacabana have been constrained by palynology to the Artinskian (Doubinger and Marocco, 1981). However, a hiatus may be observed between the Copacabana and the Mitu groups in most places, rendering the age estimate of the basal Mitu imprecise. The Pucara Group, regarded by Rosas et al. (2007) as thermal sag after Mitu extension, is attributed to the late Triassic - early Jurassic on the basis of ammonite fossils and U-Pb zircon ages from ash beds (Schaltegger et al., 2008). The aim of this study is to provide more accurate and precise age constraints for the age and duration of the Mitu Group by using U-Pb geochronology of volcanic zircon in rhyolitic lavas, and of detrital zircon in clastic sediments. For andesitic volcanic lithologies, age approximations will be obtained by Ar-Ar techniques applied to amphibole and groundmass samples. Field data were obtained from a long and apparently complete section through the Mitu, situated 120km SE of Cusco near the city of Sicuani. This section consists of typical Mitu deposits; continental red beds, breccias and andesitic lavas. However, a zircon-bearing rhyolitic lava at the bottom gives us the opportunity to date the start of Mitu sedimentation by U-Pb ID-TIMS; this analysis will provide a precise age for the base of the Mitu group for the first time. In the Sicuani area the Mitu unconformably overlies the Ambo group, suggesting that the entire Copacabana is missing. Laser-ablation ICP-MS U-Pb data of detrial zircons from a sandstone just below the unconformity indicate a maximum age of latest Carboniferous (303Ma) for the underlying Ambo group. This maximum age overlaps with the palynological age of the lower Copacabana (Azcuy et al., 2002), raising the question whether the Ambo and Copacabana are truly diachronous or just coeval units of different sedimentary facies associations. In another section, 100km W of Cusco, near the city of Abancay, we found Mitu sediments overlying the Copacabana Group. Here the Copacabana contains well preserved plant fossils of the lycopsids family also found elsewhere in Peru and Bolivia. Lack of acidic volcanism during Mitu extension in this region prevents from dating of lavas using the U-Pb method. The detrital zircon population in a sandstone in the lowermost part of the Mitu was analysed for U-Pb ages, using LA-ICP-MS techniques. The youngest zircons in the population are around 235 Ma hence providing a maximum age for the onset of Mitu group sedimentation. The Artinskian age for the upper Copacabana from Doubinger and Marocco (1981) has also been obtained from the Abancay region, establishing a hiatus of some 50 Myrs between the two units. The Mitu Group is intruded by a 220 Ma granite body (Lipa and Saraiva, 2008) indicating significant burial of the sediments at this time. 500km SE of Cusco, on the Bolivian shores of lake Titicaca, the Ambo Group features plant fossils of the Lycopsids family like those found in the Copacabana near Abancay. Our detrital zircon LA-ICPMS study on a quartz arenite just below the fossils indicates a maximum U-Pb age of 343Ma. However a zircon-bearing ash bed will allow for more precise calibration of the fossil age by ID-TIMS techniques. The zircon U-Pb data will provide a test whether the Copacabana and the Ambo group are indeed diachronous or just lateral variations of a sedimentary system