Analysis of Atlantic and Northern Gulf Coast Wetland Bacterial Extracellular Enzyme Activity

Sea-level rise is projected to cause saltwater marshes to migrate landward replacing brackish and freshwater marshes. Coastal wetlands are important sinks of carbon, phosphorous, and nitrogen, so it is important to understand the function of their microbial communities. This study aims to categorize the difference in function between different spatially distinct wetland marsh types in advance of the expected alteration of the wetland ecosystems. Extracellular microbial enzymatic activity was measured to understand organic matter decomposition and nutrient mineralization in different marsh types. We measured the activities of the extracellular enzymes β-glucosidase, NAGase, peroxidase, phenol oxidase, and phosphatase across sites along the Northern Gulf of Mexico and Atlantic coast. Both tidal salt and tidal fresh marsh sediment were sampled at each location. Higher salinity depressed the activity of NAGase. Salinity did not have a significant effect on phosphatase activity. High salinity slightly repressed carbon-degrading enzyme β-glucosidase activity but increased peroxidase and phenol oxidase activities. Sediments with high organic matter content had lower enzyme activities. Warmer water temperature sites tended to exhibit higher overall enzyme activity. This study finds that increasingly saline wetlands will cause a change in nutrient cycling functionality. Saltwater intrusion into fresh marsh will reduce the capacity for nitrate removal leading to potential coastal eutrophication, and saltwater intrusion will increase carbon metabolism leading to less accretion than in freshwater marshes further amplifying the effect of sea-level rise

Use of a geometric rule or absolute vectors: Landmark use by Clark’s nutcrackers (\u3ci\u3eNucifraga columbiana\u3c/i\u3e)

Clark’s nutcrackers (Nucifraga columbiana) were trained to search for a hidden goal located in the center of a four-landmark array. Upon completion of training, the nutcrackers were presented with tests that expanded the landmark array in the east-west direction, north-south direction and in both directions simultaneously. Although the birds learned to search accurately at the center of the landmark array during training, this search pattern did not transfer to the expansion tests. The nutcrackers searched at locations defined by absolute distance and/or direction relationships with landmarks in the training array. These results contrast with those from experiments with nutcrackers in which an abstract geometric rule was learned. This difference appears due to differences in the experimental paradigms used during training

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN.

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (-1.0_{-1.1}^{+0.9})  eV^{2}. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of 2 and provides model-independent input to cosmological studies of structure formation

Commissioning of the vacuum system of the KATRIN Main Spectrometer

The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. The strong magnetic field that guides the beta-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300{\deg}C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure

Commissioning of the vacuum system of the KATRIN Main Spectrometer

The KATRIN experiment will probe the neutrino mass by measuring the beta-electron energy spectrum near the endpoint of tritium beta-decay. An integral energy analysis will be performed by an electro-static spectrometer (Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m^3, and a complex inner electrode system with about 120000 individual parts. The strong magnetic field that guides the beta-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300{\deg}C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016

Analysis methods for the first KATRIN neutrino-mass measurement

We report on the dataset, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the β-decay kinematics of molecular tritium. The source is highly pure, cryogenic T2 gas. The β electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts β electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise measurement of the high-energy spectral tail. After detailed theoretical studies, simulations, and commissioning measurements, extending from the molecular final-state distribution to inelastic scattering in the source to subtleties of the electromagnetic fields, our independent, blind analyses allow us to set an upper limit of 1.1 eV on the neutrino-mass scale at a 90% confidence level. This first result, based on a few weeks of running at a reduced source intensity and dominated by statistical uncertainty, improves on prior limits by nearly a factor of two. This result establishes an analysis framework for future KATRIN measurements, and provides important input to both particle theory and cosmology