Extragalactic line surveys

40 years have passed since the first molecular detection outside our Galaxy. Since then, our knowledge on the distribution, kinematics and composition of the molecular material in the extragalactic ISM has built up significantly based not only on the carbon monoxide observations but also in the more than 50 molecular species detected. In particular, line surveys have been proven to be excellent tools to study the chemical composition in the nuclei of galaxies. Such studies have been favored by the increasing instantaneous bandwidth of current mm and sub-mm facilities. Here I will summarize the highlights of extragalactic molecular spectroscopy, mostly focusing in the results from molecular line surveys published in the last few years as well as the aims of still ongoing projects.Comment: 9 pages, 2 figures, in Proceedings of the 280th Symposium of the International Astronomical Unio

Dynamics of particle clouds in ambient currents with application to open-water sediment disposal

CIVINS (Civilian Institutions) Thesis documentOpen-water sediment disposal is used in many applications around the world, including land reclamation, dredging, and contaminated sediment isolation. Timely examples include the land reclamation campaign currently underway in Singapore and the Boston Harbor Navigation Improvement Project. Both of these projects required the precise dumping of millions of cubic meters of purchased sediment, in the former example, and dredged material (both clean and contaminated), in the latter example. This shows the significant economic and environmental interests in the accurate placement of sediment, which requires knowledge of how particle clouds behave in ambient currents. Flow visualization experiments were performed in a glass-walled recirculating water channel to model open-water sediment disposal by releasing particles quasi-instantaneously into the channel with ambient currents. For releases at the surface, criteria were developed to characterize ambient currents as weak, transitional, or strong as a function of particle size. In weak ambient currents, particle clouds advected downstream with a velocity equal to the ambient current, but otherwise the behavior and structure was similar to that in quiescent conditions. The parent cloud's entrainment coefficient (alpha) increased with decreasing particle size and elevation above the water surface, between values of 0.10 and 0.72, but for most experiments, the range was less significant (0.11 to 0.24). A substantial portion of the mass initially released, up to 30%, was not incorporated into the parent cloud and formed the trailing stem. This was also heavily dependent on the initial release variables, with the greatest sensitivity on particle size. The loss of sediment during descent, defined as the fraction of mass missing a designated target with a radius equal to the water depth, was quantified and found to increase sharply with current speed.http://archive.org/details/dynamicsofpartic109454945CIVINSApproved for public release; distribution is unlimited

Immobilisierung lebender Bakterien in wasserbeständigen Polymerfasern zur Herstellung einer aktiven Membran

Ein Ziel dieser Arbeit war die Immobilisierung lebender Bakterien in Fasern aus polymeren Materialien durch die Technik des Elektrospinnens. Neben der Verwendung von wasserlöslichen Polymeren, wurde besonderes Augenmerk auf eine Einlagerung der Bakterien in Fasern aus wasserbeständigen Polymeren, wie Polystyrol und Polyvinylbutyral gerichtet. Es wurde ein System auf der Basis von Hydrogelen entwickelt, das es ermöglichte, Bakterien zusammen mit den Polymeren aus organischen Lösungsmitteln zu verarbeiten. Es konnten wasserfeste Membranen, bestehend aus elektrogesponnenen Faservliesen erhalten werden, worin die immobilisierten Bakterien in der Lage waren, Stoffe aus einem wässrigen Medium aufzunehmen und umzuwandeln. Ein weiterer Teil dieser Arbeit befasste sich mit dem Aufbringen dünner Schichten elektrogesponnener Vliese aus Polyamid auf Trägermaterialien zur Herstellung von Filtern für Anwendungen in der Wasseraufbereitung. Die Filter wurden auf ihre Eignung zur Entfernung von Bakterien aus wässrigen Medien getestet, wobei sich zeigte, dass eine vollständige Entfernung der Bakterien realisiert werden konnte

HisB as novel selection marker for gene targeting approaches in Aspergillus niger

Background For Aspergillus niger, a broad set of auxotrophic and dominant resistance markers is available. However, only few offer targeted modification of a gene of interest into or at a genomic locus of choice, which hampers functional genomics studies. We thus aimed to extend the available set by generating a histidine auxotrophic strain with a characterized hisB locus for targeted gene integration and deletion in A. niger. Results A histidine-auxotrophic strain was established via disruption of the A. niger hisB gene by using the counterselectable pyrG marker. After curing, a hisB - , pyrG - strain was obtained, which served as recipient strain for further studies. We show here that both hisB orthologs from A. nidulans and A. niger can be used to reestablish histidine prototrophy in this recipient strain. Whereas the hisB gene from A. nidulans was suitable for efficient gene targeting at different loci in A. niger, the hisB gene from A. niger allowed efficient integration of a Tet-on driven luciferase reporter construct at the endogenous non-functional hisB locus. Subsequent analysis of the luciferase activity revealed that the hisB locus is tight under non-inducing conditions and allows even higher luciferase expression levels compared to the pyrG integration locus. Conclusion Taken together, we provide here an alternative selection marker for A. niger, hisB, which allows efficient homologous integration rates as well as high expression levels which compare favorably to the well-established pyrG selection marker.EC/FP7/303864/EU/Bridging the world of fungi and dementia/PROFITSTU Berlin, Open-Access-Mittel - 201

A convolutional neural network for spatial downscaling of satellite-based solar-induced chlorophyll fluorescence (SIFnet)

Gross primary productivity (GPP) is the sum of leaf photosynthesis and represents a crucial component of the global carbon cycle. Space-borne estimates of GPP typically rely on observable quantities that co-vary with GPP such as vegetation indices using reflectance measurements (e.g., NDVI, NIRv, and kNDVI). Recent work has also utilized measurements of solar-induced chlorophyll fluorescence (SIF) as a proxy for GPP. However, these SIF measurements are typically coarse resolution while many processes influencing GPP occur at fine spatial scales. Here, we develop a Convolutional Neural Network (CNN), named SIFnet, that increases the resolution of SIF from the TROPOspheric Monitoring Instrument (TROPOMI) on board of the satellite Sentinel-5P by a factor of 10 to a spatial resolution of 500 m. SIFnet utilizes coarse SIF observations together with high resolution auxiliary data. The auxiliary data used here may carry information related to GPP and SIF. We use training data from non-US regions between April 2018 until March 2021 and evaluate our CNN over the conterminous United States (CONUS). We show that SIFnet is able to increase the resolution of TROPOMI SIF by a factor of 10 with a r2 and RMSE metrics of 0.92 and 0.17 mW m&minus;2 sr&minus;1 nm&minus;1, respectively. We further compare SIFnet against a recently developed downscaling approach and evaluate both methods against independent SIF measurements from Orbiting Carbon Observatory 2 and 3 (OCO-2/3). SIFnet performs systematically better than the downscaling approach (r = 0.78 for SIFnet, r = 0.72 for downscaling), indicating that it is picking up on key features related to SIF and GPP. Examination of the feature importance in the neural network indicates a few key parameters and the spatial regions these parameters matter. Namely, the CNN finds low resolution SIF data to be the most significant parameter with the NIRv vegetation index as the second most important parameter. NIRv consistently outperforms the recently proposed kNDVI vegetation index. Advantages and limitations of SIFnet are investigated and presented through a series of case studies across the United States. SIFnet represents a robust method to infer continuous, high spatial resolution SIF data.</p

AFM tip-based nanomachining with increased cutting speed at the tool-workpiece interface

This paper reports a study towards enhancing the throughput of the Atomic Force Microscope (AFM) tip-based nanomachining process by increasing the cutting speed at the interface between the tool and the workpiece. A modified AFM set-up was implemented, which combined the fast reciprocating motions of a piezoelectric actuator, on which the workpiece was mounted, and the linear displacement of the AFM stage, which defined the length of produced grooves. The influence of the feed, the feed direction and the cutting speed on the machined depth and on the chip formation was studied in detail when machining poly(methyl methacrylate). A theoretical cutting speed over 5 m/min could be achieved with this set-up when the frequency of the piezoelectric actuator reciprocating motions was 40 kHz. This is significantly better than the state of the art for AFM-based nanomachining, which is currently less than 1 m/min.</p

Dynamics of particle clouds in ambient currents with application to open-water sediment disposal

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 255-259).Open-water sediment disposal is used in many applications around the world, including land reclamation, dredging, and contaminated sediment isolation. Timely examples include the land reclamation campaign currently underway in Singapore and the Boston Harbor Navigation Improvement Project. Both of these projects required the precise dumping of millions of cubic meters of purchased sediment, in the former example, and dredged material (both clean and contaminated), in the latter example. This shows the significant economic and environmental interests in the accurate placement of sediment, which requires knowledge of how particle clouds behave in ambient currents. Flow visualization experiments were performed in a glass-walled recirculating water channel to model open-water sediment disposal by releasing particles quasi-instantaneously into the channel with ambient currents. For releases at the surface, criteria were developed to characterize ambient currents as "weak," "transitional," or "strong" as a function of particle size. In "weak" ambient currents, particle clouds advected downstream with a velocity equal to the ambient current, but otherwise the behavior and structure was similar to that in quiescent conditions. The parent cloud's entrainment coefficient (??) increased with decreasing particle size and elevation above the water surface, between values of 0.10 and 0.72, but for most experiments, the range was less significant (0.11 to 0.24). A substantial portion of the mass initially released, up to 30 %, was not incorporated into the parent cloud and formed the trailing stem. This was also heavily dependent on the initial release variables, with the greatest sensitivity on particle size. The "loss" of sediment during descent, defined as the fraction of mass missing a designated target with a radius equal to the water depth, was quantified and found to increase sharply with current speed. The cloud number (Nc), which relates the particle settling velocity to a characteristic thermal descent velocity, provides a basis for scaling laboratory results to the real world and formulating guidelines to reduce the losses that could result from open-water sediment disposal.by Robert James Gensheimer, III.S.M