Aggregation of Fine Particles at the Sediment-Water Interface

The presence of a bottom sediment layer agitated by mechanical stirring or by resident organisma (tubificid oligochaetes) significantly increases the rate at which fine (1 µm) cohesive particles are removed from suspension in laboratory columns. Measured rates of particle removal are equivalent to deposition velocities ranging from 0.23 m per day to 0.41 m per day. These rates are an order of magnitude faster than deposition by gravitational settling or coagulation with larger particles in the water column as observed in experimental controls. It is hypothesized that the increased removal rate is the result of aggregation in a sediment layer at the bed-water interface characterized by loosely bound (fluffy), porous material hydrodynamically coupled to the water column. According to this hypothesis particle removal occurs when motion of the overlying water or organism activity causes suspended fine particles to collide with and stick to the interfacial sediment. This new hypothesis is supported by the mass and size distribution of tracer particles recovered in cores and sediment traps at a coastal site and by theoretical estimates of interfacial aggregation rates.This work was supported by EPA grant CR-81181-01-01, by the MIT Sea Grant College Program, under NOAA Grant NA86AA-D-SG089, and by a postgraduate scholarship awarded to the second author by the Natural Sciences and Engineering Research Council of Canada.https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/92JC0182

Leren van de mineralenbalans

This study is part of a series of exploratory studies under the banner of the ODI project. ODI stands for 'Objectives, Decision-making and Information needs of agrarian entrepreneurs'. The project's aims are threefold: (a) to gain insight in the information needs of agrarian entrepreneurs; (b) to investigate the potential of new information and communication technologies in catering for these needs; and (c) to develop appropriate research strategies for identifying information needs. In view of the current interest in environmental issues in general, and manure and mineral problems in particular, ODI has chosen to explore these questions in relation to mineral management on dairy farms in the Netherland

Renal cell carcinoma incidence rates and trends in young adults aged 20-39 years

Background: The burden of renal cell carcinoma (RCC) in young adults received marginal attention. We assessed contemporary gender, race and stage-specific incidence and trends of RCC among young adults (20-39 years-old) in the United States.Methods: Within Surveillance, Epidemiology, and End Results database (2000-2016), patients aged 20-39 years with histologically confirmed RCC were included. Age-standardized incidence rates (ASR per 100,000 person-years) were estimated. Temporal trends were calculated through joinpoint regression analyses to describe the average annual percent change (AAPC).Results: From 2000-2016, 7767 new RCC cases were recorded (ASR 0.6, AAPC + 5.0 %, p < 0.001). ASRs were higher in males than in females (0.7 and 0.5, respectively) and increased significantly in both genders (AAPC + 5.0 % and + 4.7 % both p < 0.001, respectively). Non-Hispanic American Indian/Alaska Native had the highest incidence (ASR 1.0) vs. non-Hispanic Asian or Pacific Islander the lowest (ASR 0.3). ASRs significantly increased in all ethnic groups. T1aNOMO and T1bNOMO stages showed the highest incidence and increase (ASR 0.3, AAPC + 5.9 %, p < 0.001 and ASR 0.1, AAPC + 5.7 %, p < 0.001, respectively). Also regional and distant stages increased (AAPC + 3.7 %, p = 0.001 and AAPC + 1.5 %, p = 0.06). The most frequent tumor characteristics were G2 (44.4 %, ASR 0.3, AAPC + 6.3 %, p < 0.001) and G1 (13.1 %, ASR 0.1, AAPC + 1.1 %, p = 0.2), as well as clear cell histology (54.8 %, ASR 0.3, AAPC + 7.6 %, p < 0.001).Conclusions: RCC in young adults is rare, but increasing. This is mainly due to T1aN0M0 tumors. Nonetheless, also regional diseases are significantly increasing. Differences between ethnic groups exist and may warrant further research

Metabolic syndrome predicts worse perioperative outcomes in patients treated with partial nephrectomy for renal cell carcinoma

OBJECTIVE: To test the association between metabolic syndrome (MetS) and its components (high blood pressure, body mass index [BMI] 65 30, altered fasting glucose, low high-density lipoprotein cholesterol and high triglycerides) on perioperative outcomes after partial nephrectomy (PN). METHODS: Within the National Inpatient Sample database (2000-2015) we identified all PN patients. First, temporal trends of MetS were reported. Second, the effect of MetS components was tested in multivariable logistic regression models predicting overall and specific perioperative complications. Third, we tested for dose-response from the concomitant effect of multiple MetS components. All models were weighted and adjusted for clustering, as well as all available patient and hospital characteristics. RESULTS: Of 25,875 patients: (1) 59.3% had high blood pressure, (2) 14.7% had BMI 65 30, (3) 21.7% had altered fasting glucose, (4) 20.2% had high triglycerides, and (5) <0.01% had low high-density lipoprotein cholesterol. One vs 2 vs 3 vs 4 MetS components were recorded in 34.9% vs 22.9% vs 8.9% vs 2.2% patients. Of all, 11.1% exhibited 65 3 components and qualified for MetS. The rates of MetS increased over time (estimated annual percentage changes: +12.0%;P <.001). The 4 tested MetS components (high blood pressure, BMI 65 30, altered fasting glucose, and high triglycerides) achieved independent predictor status in multivariable models predicting overall, cardiac, miscellaneous medical, vascular, and respiratory complications, as well as transfusions. Moreover, a statistically significant dose-response was confirmed for the same endpoints. CONCLUSION: MetS and its components consistently and strongly predict perioperative complications after PN. Moreover, the strength of the effect was directly proportional to the number of MetS components exhibited by each individual patient, even if formal MetS diagnosis of 65 3 components has not been m

Martian Atmospheric Temperature and Density Profiles During the First Year of NOMAD/TGO Solar Occultation Measurements

We present vertical profiles of temperature and density from solar occultation (SO) observations by the “Nadir and Occultation for Mars Discovery” (NOMAD) spectrometer on board the Trace Gas Orbiter during its first operational year, which covered the second half of Mars Year 34. We used calibrated transmittance spectra in 380 scans, and apply an in-house pre-processing to clean data systematics. Temperature and CO2 profiles up to about 90 km, with consistent hydrostatic adjustment, are obtained, after adapting an Earth-tested retrieval scheme to Mars conditions. Both pre-processing and retrieval are discussed to illustrate their performance and robustness. Our results reveal the large impact of the MY34 Global Dust Storm (GDS), which warmed the atmosphere at all altitudes. The large GDS aerosols opacity limited the sounding of tropospheric layers. The retrieved temperatures agree well with global climate models (GCM) at tropospheric altitudes, but NOMAD mesospheric temperatures are wavier and globally colder by 10 K in the perihelion season, particularly during the GDS and its decay phase. We observe a warm layer around 80 km during the Southern Spring, especially in the Northern Hemisphere morning terminator, associated to large thermal tides, significantly stronger than in the GCM. Cold mesospheric pockets, close to CO2 condensation temperatures, are more frequently observed than in the GCM. NOMAD CO2 densities show oscillations upon a seasonal trend that track well the latitudinal variations expected. Results uncertainties and suggestions to improve future data re-analysis are briefly discussed

Diversity of experimentation by farmers engaged in agroecology

International audienceAbstractAgroecology questions the production of generic knowledge. Rather than searching for the best practices for large-scale transfer, it would be more efficient to help farmers find their own solutions. A promising activity for farmers is experimentation because it answers their needs and helps them learn. However, how agroecological practices are tested by farmers in their own experiments is still poorly known. In this study, we examined the short-term experimental activity, i.e., experiments carried out at a yearly scale in pre-defined fields. Seventeen farmers in south eastern France were surveyed. The farmers practiced conventional or organic farming and cultivated either arable or market garden crops. Experiments on agroecological practices were characterized, located along a timeline, and discussed with them. To conduct the interviews with the farmers, each experiment was described in three stages: (1) designing the experiment, (2) managing it in real time, and (3) evaluating the results of the experiment. The data collected in the interviews were first analyzed to build a descriptive framework of farmers’ experiments, after which hierarchical cluster analysis was used to analyze the diversity of the farmers’ experiments. Here, we propose for the first time a generic framework to describe farmers’ experiments at a short time scale based on the consistency between the Design, Management, and Evaluation stages. We used the framework to characterize the diversity of farmers’ experiments and identified four clusters. The originality of this work is both building a descriptive framework resulting from in-depth analyses of farmers’ discourse and using statistical tools to identify and interpret the groups of experiments. Our results provide a better understanding of farmers’ experiments and suggest tools and methods to help them experiment, a major challenge in the promotion of a large-scale agroecological transition

Water vapor vertical distribution on Mars during perihelion season of MY 34 and MY 35 with ExoMars‐TGO/NOMAD observations

The water vapor in the Martian atmosphere plays a significant role in the planet’s climate, being crucial in most of the chemical and radiative transfer processes. Despite its importance, the vertical distribution of H2O in the atmosphere has not still been characterized precisely enough. The recent ExoMars Trace Gas Orbiter (TGO) mission, with its Nadir and Occultation for MArs Discovery (NOMAD) instrument, has allowed us to measure the H2O vertical distribution with unprecedented resolution. Recent studies of vertical profiles have shown that high dust concentration in the atmosphere, in particular during dust storms, induces an efficient transport of the H2O to higher altitudes, from 40 km up to 80 km. We study the H2O vertical distribution in a subset of solar occultations during the perihelion of two Martian years (MYs), including the 2018 Global Dust Storm (GDS), in order to compare the same Martian season under GDS and non-GDS conditions. We present our state-of-the-art retrieval scheme, and we apply it to a combination of two diffraction orders, which permits sounding up to about 100 km. We confirm recent findings of H2O increasing at high altitudes during Ls = 190-205° in MY 34, reaching abundances of about 150 ppmv at 80 km in both hemispheres not found during the same period of MY 35. We found a hygropause’s steep rising during the GDS from 30 up to 80 km. Furthermore, strong supersaturation events have been identified at mesospheric altitudes even in presence of water ice layers retrieved by the IAA team

Kvalitet og integritet i økologiske æg, kyllinge- og svinekødsprodukter (QEMP)

Gode muligheder for at påvirke kvalitet og øge diversiteten ved at ’skrue på’ race, fodring og slagtealder Fortsat fokus på kvalitet nødvendig (især samspil mellem frilandsproduktion og kvalitet)

Martian atmospheric temperature and density profiles during the 1st year of NOMAD/TGO solar occultation measurements

We present vertical profiles of temperature and density from solar occultation (SO) observations by the “Nadir and Occultation for Mars Discovery” (NOMAD) spectrometer on board the Trace Gas Orbiter (TGO) during its first operational year, which covered the second half of Mars Year 34. We used calibrated transmittance spectra in 380 scans, and apply an in-house pre-processing to clean data systematics. Temperature and CO2 profiles up to about 90 km, with consistent hydrostatic adjustment, are obtained, after adapting an Earth-tested retrieval scheme to Mars conditions. Both pre-processing and retrieval are discussed to illustrate their performance and robustness. Our results reveal the large impact of the MY34 Global Dust Storm (GDS), which warmed the atmosphere at all altitudes. The large GDS aerosols opacity limited the sounding of tropospheric layers. The retrieved temperatures agree well with global climate models (GCM) at tropospheric altitudes, but NOMAD mesospheric temperatures are wavier and globally colder by 10 K in the perihelion season, particularly during the GDS and its decay phase. We observe a warm layer around 80 km during the Southern Spring, especially in the Northern Hemisphere morning terminator, associated to large thermal tides, significantly stronger than in the GCM. Cold mesospheric pockets, close to CO2 condensation temperatures, are more frequently observed than in the GCM. NOMAD CO2 densities show oscillations upon a seasonal trend that track well the latitudinal variations expected. Results uncertainties and suggestions to improve future data re-analysis are briefly discussed