Where communities intermingle, diversity grows - The evolution of topics in ecosystem service research

We analyze how the content of ecosystem service research has evolved since the early 1990s. Conducting a computational bibliometric content analysis we process a corpus of 14,118 peer-reviewed scientific article abstracts on ecosystem services (ES) from Web of Science records. To provide a comprehensive content analysis of ES research literature, we employ a latent Dirichlet allocation algorithm. For three different time periods (1990-2000, 2001-2010, 2011-2016), we derive nine main ES topics arising from content analysis and elaborate on how they are related over time. The results show that natural science-based ES research analyzes oceanic, freshwater, agricultural, forest, and soil ecosystems. Pollination and land cover emerge as traceable standalone topics around 2001. Social science ES literature demonstrates a reflexive and critical lens on the role of ES research and includes critiques of market-oriented perspectives. The area where social and natural science converge most is about land use systems such as agriculture. Overall, we provide evidence of the strong natural science foundation, the highly interdisciplinary nature of ES research, and a shift in social ES research towards integrated assessments and governance approaches. Furthermore, we discuss potential reasons for observable topic developments.Peer reviewe

Regeneration and recovery in the fetal nervous system after radiation injury

Previous studies showed that recovery from destructive injury in 12-day fetal rats (23 to 34 somite pairs) exposed to 150 R appeared to be remarkably good except for minor abnormalities of the brain and spinal cord in some animals and occasionally microphthalmia. Nothing more was known of the morphogenesis of this restitution. A series of rats irradiated on the 12th fetal day was studied histologically and in other ways from a few hours after exposure to adulthood. Five to eight hours after 150 R there was widespread necrosis of certain classes of primitive proliferative cells in the nervous system and other tissues, but residual cells had resumed proliferative activity. By 24 h regeneration of the proliferative cells was advanced and most necrotic cells had disappeared, and at 48 h the irradiated fetus closely resembled the normal. There were very few residual dead cells, and minute foci of proliferative cell rosettes were present in the midline of the ventral spinal cord and brain stem. Seventy-two and ninety-six hours after irradiation the fetuses looked like their normal counterparts except for persistent or resolving minute rosettes. At later stages to adulthood, effects of the rosette formation were not visible. In some individuals the spinal cords were reduced slightly in overall cross-sectional area and the pallium was shorter than normal. Other irradiated animals could not be distinguished from normals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23969/1/0000218.pd

Identification of genes required for glucan exopolysaccharide production in Lactobacillus johnsonii suggests a novel mechanism of biosynthesis

Lactobacillus johnsonii FI9785 makes two capsular exopolysaccharides-a heteropolysaccharide (EPS2) encoded by the eps operon and a branched glucan homopolysaccharide (EPS1). The homopolysaccharide is synthesized in the absence of sucrose, and there are no typical glucansucrase genes in the genome. Quantitative proteomics was used to compare the wild type to a mutant where EPS production was reduced to attempt to identify proteins associated with EPS1 biosynthesis. A putative bactoprenol glycosyltransferase, FI9785_242 (242), was less abundant in the Δ eps_cluster mutant strain than in the wild type. Nuclear magnetic resonance (NMR) analysis of isolated EPS showed that deletion of the FI9785_242 gene ( 242) prevented the accumulation of EPS1, without affecting EPS2 synthesis, while plasmid complementation restored EPS1 production. The deletion of 242 also produced a slow-growth phenotype, which could be rescued by complementation. 242 shows amino acid homology to bactoprenol glycosyltransferase GtrB, involved in O-antigen glycosylation, while in silico analysis of the neighboring gene 241 suggested that it encodes a putative flippase with homology to the GtrA superfamily. Deletion of 241 also prevented production of EPS1 and again caused a slow-growth phenotype, while plasmid complementation reinstated EPS1 synthesis. Both genes are highly conserved in L. johnsonii strains isolated from different environments. These results suggest that there may be a novel mechanism for homopolysaccharide synthesis in the Gram-positive L. johnsonii IMPORTANCE Exopolysaccharides are key components of the surfaces of their bacterial producers, contributing to protection, microbial and host interactions, and even virulence. They also have significant applications in industry, and understanding their biosynthetic mechanisms may allow improved production of novel and valuable polymers. Four categories of bacterial exopolysaccharide biosynthesis have been described in detail, but novel enzymes and glycosylation mechanisms are still being described. Our findings that a putative bactoprenol glycosyltransferase and flippase are essential to homopolysaccharide biosynthesis in Lactobacillus johnsonii FI9785 indicate that there may be an alternative mechanism of glucan biosynthesis to the glucansucrase pathway. Disturbance of this synthesis leads to a slow-growth phenotype. Further elucidation of this biosynthesis may give insight into exopolysaccharide production and its impact on the bacterial cell

Control of quantum interference in molecular junctions: Understanding the origin of Fano and anti- resonances

We investigate within a coarse-grained model the conditions leading to the appearance of Fano resonances or anti-resonances in the conductance spectrum of a generic molecular junction with a side group (T-junction). By introducing a simple graphical representation (parabolic diagram), we can easily visualize the relation between the different electronic parameters determining the regimes where Fano resonances or anti-resonances in the low-energy conductance spectrum can be expected. The results obtained within the coarse-grained model are validated using density-functional based quantum transport calculations in realistic T-shaped molecular junctions.Comment: 5 pages, 5 figure

Herramientas para la detección y seguimiento de personas a partir de cámaras de seguridad

La inseguridad es un problema que afecta en mayor o menor medida a todas las ciudades del mundo. Las ciudades más informatizadas hacen uso de la video-vigilancia para combatirla, montando en muchos de los casos centros de monitoreo con cientos de cámaras. En su mayoría, estos centros cuentan con grupos de personas para realizar la tarea de observación, sin embargo, la velocidad de cómputo actual nos da la posibilidad de automatizar muchas de sus tareas diarias. En este trabajo, se presenta una plataforma de análisis de video que se está desarrollando en la UNCPBA para facilitar el seguimiento de una persona a través de diferentes cámaras, utilizando técnicas de proyección que convierten los puntos detectados desde las diferentes cámaras a un único espacio georeferenciado. Se presenta una discusión de los algoritmos utilizados para el seguimiento, algunos problemas propios que se suceden en este tipo de sistemas y los resultados preliminares obtenidos.XIV Workshop Computación Gráfica, Imágenes y Visualización (WCGIV)

Adaptive State Estimation for Nonminimum-Phase Systems with Uncertain Harmonic Inputs

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90727/1/AIAA-2011-6315-484.pd