Rice Plant Height Monitoring from Space with Bistatic Interferometry

This chapter provides an overview of the possibility to derive paddy rice plant heights with spaceborne bistatic SAR interferometry (InSAR). By using the only available interferometer in space, TanDEM-X, an investigation of rice crops located in Turkey is performed. Before analyzing the main outcomes, an introduction to the generation of elevation models with InSAR is provided, with a special focus on the agricultural land cover. The processing chain and the modifications foreseen to properly produce plant elevations and a roadmap for the quality assessment are described. The results obtained, with a very high interferometric coherence supporting an accurate estimation due to a limited electromagnetic wave penetration into the canopy, support a temporal change analysis on a field-by-field basis. For the purpose, an automatic approach to segment the fields without external auxiliary data is also provided. The study is concluded with an analysis of the impact of the wave polarization in the results

Polarization Impact in TanDEM-X Data Over Vertical-Oriented Vegetation: The Paddy-Rice Case Study

It has been recently shown that the TanDEM-X mission is capable of tracking the plant growth of rice paddies. The precision of the elevation measure depends on the physical interaction between the synthetic aperture radar (SAR) signal and the canopy. In this letter, this interaction is studied by considering the signal polarization. In particular, the vertical and horizontal wave polarizations are compared, and their performance in the temporal mapping of the crop height is analyzed. The temporal elevation difference analysis shows a monotonically increasing trend within the reproductive stage of the canopy, with maximum height discrepancies between polarizations of about 9 cm. From an operational point of view of InSAR-based vegetation height measurements, this letter demonstrates that the oriented structure of the canopy shall be considered not only in polarimetric InSAR studies but also in the interpretation of bistatic spaceborne interferometric elevation models

Detecting Building Layovers in a SAR Interferometric Processor Without External References

A novel technique for the derivation of building layovers is presented. It makes use of the behaviour of the geocoding processing stage embedded in an interferometric SAR processor for this particular case. It is shown how layover pixels create a regular pattern in the range mapping matrices, with a multiple mapping of a single SAR pixel for different DEM cells. The exploitation of these patterns yields a generation of a layover map without the use of external supports. The integration in an interferometric processor with a limited additional computational load and the capability to isolate building signatures are additional benefits. The algorithm is tested on a TanDEM-X spotlight acquisition over Berlin (Germany)

Structural Features of Antitumor Titanium Agents and Related Compounds

Previous studies established some Ti compounds as having marked activity against tumors of the gastrointestinal tract and lack of side effects common to widely used cytostatic agents. We describe pertinent structural features of known antitumor Ti agents and other potentially active compounds. Particularly noteworthy features are that Ti-O bonds are short and Ti-O-Ti bond angles are large, demonstrating that in these compounds the O binding has high s-character approaching sp hybridization

In vivo functional and molecular characterization of the Penicillin-Binding Protein 4 (DacB) of Pseudomonas aeruginosa

Background: Community and nosocomial infections by Pseudomonas aeruginosa still create a major therapeutic challenge. The resistance of this opportunist pathogen to β-lactam antibiotics is determined mainly by production of the inactivating enzyme AmpC, a class C cephalosporinase with a regulation system more complex than those found in members of the Enterobacteriaceae family. This regulatory system also participates directly in peptidoglycan turnover and recycling. One of the regulatory mechanisms for AmpC expression, recently identified in clinical isolates, is the inactivation of LMM-PBP4 (Low-Molecular-Mass Penicillin-Binding Protein 4), a protein whose catalytic activity on natural substrates has remained uncharacterized until now. Results: We carried out in vivo activity trials for LMM-PBP4 of Pseudomonas aeruginosa on macromolecular peptidoglycan of Escherichia coli and Pseudomonas aeruginosa. The results showed a decrease in the relative quantity of dimeric, trimeric and anhydrous units, and a smaller reduction in monomer disaccharide pentapeptide (M5) levels, validating the occurrence of D,D-carboxypeptidase and D,D-endopeptidase activities. Under conditions of induction for this protein and cefoxitin treatment, the reduction in M5 is not fully efficient, implying that LMM-PBP4 of Pseudomonas aeruginosa presents better behaviour as a D,D-endopeptidase. Kinetic evaluation of the direct D,D-peptidase activity of this protein on natural muropeptides M5 and D45 confirmed this bifunctionality and the greater affinity of LMM-PBP4 for its dimeric substrate. A three-dimensional model for the monomeric unit of LMM-PBP4 provided structural information which supports its catalytic performance. Conclusions: LMM-PBP4 of Pseudomonas aeruginosa is a bifunctional enzyme presenting both D,D-carboxypeptidase and D,D-endopeptidase activities; the D,D-endopeptidase function is predominant. Our study provides unprecedented functional and structural information which supports the proposal of this protein as a potential hydrolase-autolysin associated with peptidoglycan maturation and recycling. The fact that mutant PBP4 induces AmpC, may indicate that a putative muropeptide-subunit product of the DD-EPase activity of PBP4 could be a negative regulator of the pathway. This data contributes to understanding of the regulatory aspects of resistance to β-lactam antibiotics in this bacterial model.Spanish Ministerio de Ciencia e Innovación, DIVINOCELL FP7 HEALTH-F3-2009-223431 from the European Commission and DIUFRO08-0060 from the Dirección de Investigación of the Universidad de La Frontera of ChilePeer Reviewe

Remote monitoring to predict bridge scour failure using Interferometric Synthetic Aperture Radar (InSAR) stacking techniques

Scour is the removal of ground material in water bodies due to environmental changes in water flow. It particularly occurs at bridge piers and the holes formed can make bridges susceptible to collapse. The most common cause of bridge collapse is due to scour occurring during flooding, some failures causing loss of life and most resulting in significant transport disruption and economic loss. Consequently, failure of bridges due to scour is of great concern to bridge asset owners, and is currently very difficult to predict since conventional assessment methods foresee very resource-demanding monitoring efforts in situ. This paper presents evidence of how InSAR techniques can be used to monitor bridges at risk of scour, using Tadcaster Bridge, England, as a case study. Tadcaster Bridge suffered a partial collapse due to river scour on the evening of December 29th, 2015 following a period of severe rainfall and flooding. 48 TerraSAR-X scenes over the bridge from the two-year period prior to the collapse are analysed using the small baseline subset (SBAS) interferometric synthetic aperture radar (InSAR) approach. The study highlights a distinct movement in the region of the bridge where the collapse occurred prior to the actual event. This precursor to failure observed in the data over a month before actual collapse suggests the possible use of InSAR as a means of an early warning system in structural health monitoring of bridges at risk of scour.This work was made possible by EPSRC (UK) Award 1636878, with iCase sponsorship from the National Physical Laboratory and additional funding from Laing O’Rourke

Caracterización funcional y estructural de LMM-PBP4 y análisis de su papel moderador en la integridad molecular del peptidoglicano para el modelo bacteriano "Pseudomonas aeroginosa"

Tesis doctoral inédita leída en la Universidad Aautónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 23-05-2015Nosocomial and community-acquired infections by Pseudomonas aeruginosa continue to represent a major therapeutic challenge where the choice of an appropriate antibiotic is essential. Resistance of this pathogen against β-lactam antibiotics is mainly determined by the production of inactivating enzymes (β-lactamases) AmpC type whose regulatory mechanism is much more complex than the existing in members of the Enterobacteriaceae family, by including the protein AmpR responsible for regulation of additional genes in regards to ampC, such as ampE and creD as well as dacB, involved in the overproduction of this cephalosporinase. The connection between the replacement and recycling processes of peptidoglycan and its regulatory pathways for constitutive overproduction of chromosomal AmpC β-lactamase, particularly the mechanism associated with inactivation of PBP4, raises a need for detailed structural and functional research of this LMM-PBP class C subclass C1 in Pseudomonas aeruginosa that allows to establish similarities and differences with other low molecular mass penicillin-binding proteins in this bacterial model and between functional orthologs from related species, also evaluating its participation in the metabolism of cell wall and the biology of resistance to β-lactam antibiotics. The methodological approach designed and implemented to address this Thesis demonstrated the lack of β-lactamase activity for the LMM-PBP4 native form, the presence of DD-carboxypeptidase and DD-endopeptidase activities in this protein (this last was defined as the predominant activity) and its absence at the site of cell division discarding its association with septal and bacterial divisome proteins. Its subcellular localization in the inner membrane and periplasmic space strengthens its proposal as a potential hydrolase-autolysin associated with the maturationrecycling of the peptidoglycan. The high affinity demonstrated between the β-lactam antibiotics cefoxitin and imipenem with LMM-PBP4 (purified and bound to membrane) correlates with the binding activity for these proteins and their probable inactivation and its role on constitutive overproduction of AmpC β-lactamase. The structural model for the monomeric unit of LMM-PBP4 confirms the presence of domains II and III which define it as a LMM-PBP class C subclass C1 allowing to estimate the dimension of the cavity in the active site that favors the access of large substrates and recognizes the existence of a threonine amino acid at position 386 (T386) which would accommodate the peptide chain of a second strand of peptidoglycan. These structural precedents support the development of a DD-endopeptidase activity in this protein. Analysis of the cell wall in relation to its muropeptides composition from the reference strain and mutants in regulatory proteins for AmpC production (DacB, AmpE, AmpDh2) under natural conditions, supplementationoverexpression and antibiotic inactivation of LMM-PBP4, exhibits no changes to propose an activation system for ampC via an effector of pentapeptide nature but confirms in vivo the DD-peptidase bifunctionality mentioned above. Moreover, it was achieved the identification of new muropeptides related to structure and functionality still not described in Pseudomonas aeruginos

Quality of Imported Argentine Beef

A total of 8 lots of vacuum-packed bovine rump hearts (Gluteus medius muscle) imported in Italy from Argentina were submitted to microbiological (total bacterial count, Enterobacteriaceae, Pseudomonas spp., Lactobacilli, sulfite-reducing Clostridia, Listeria monocytogenes) and physicochemical analyses (pH, total volatile basic nitrogen, color measurement and shear force) after different storage times (35, 75 and 100 days). Lactobacilli were the predominant microbial population (about 6 log cfu/cm2), causing a microbial stabilization and acidification of meat. Seventy-three Lactobacilli isolates were submitted to random amplified polymorphic DNA-polymerase chain reaction and identified, showing a high prevalence of Lactobacillus sakei (in all the samples) and Lactobacillus curvatus (in samples stored for 75 or 100 days). We observed high total volatile basic nitrogen levels (>27 mgN/100 g) in all the samples and a discoloration of beef after the opening of the packs. Our results suggest the need for a higher standardization of production conditions. Practical Applications Vacuum-packed raw beef from Argentina is globally commercialized, and it is frequently shipped to European markets. Considering the perishability of this product and the very long shelf life assigned, the availability of microbiological and physicochemical data could be useful for quality evaluations purposes. Our data indicate that a long shelf life (3–4 months) is potentially achievable, but the application of the best hygienic practices during meat production and an optimal stabilization of microflora by the selection (or addition) of lactic acid bacteria must be assured. As protein degradation and microbial population showed to be stable during the shelf life, quality characteristics that are perceived by the consumer (such as color indexes) become important parameters for a proper evaluation of meat quality

Nonnegative solutions to an elliptic problem with nonlinear absorption and a nonlinear incoming flux on the boundary

In this paper we perform an extensive study of the existence, uniqueness (or multiplicity) and stability of nonnegative solutions to the semilinear elliptic equation −∆u = λu − u p in Ω, with the nonlinear boundary condition ∂u/∂ν = u r on ∂Ω. Here Ω is a smooth bounded domain of IRd with outward unit normal ν, λ is a real parameter and p, r > 0. We also give the precise behavior of solutions for large |λ| in the cases where they exist. The proofs are mainly based on bifurcation techniques, sub-supersolutions and variational methods.Ministerio de Ciencia y TecnologíaFondo Europeo de Desarrollo Regiona