Roles of seed dispersal and environmental filters in establishment of the dominant shrubs: Morella cerifera and M. pensylvanica, on an Atlantic barrier island

Patterns of the expansion of woody cover into grasslands on barrier islands of the Virginia coast were investigated. Seed dispersal of the dominant shrub Morella spp., was sampled deploying seed traps (n = 82) throughout a landscape under shrub encroachment pressure on Hog Island, VA. Traps were placed underneath: fruiting Morella, non-fruiting Morella, co-occurring species (Iva frutescens and Baccharis halimifolia) and in grass land, (no shrub cover). Environmental filters that act upon dispersed seeds and subsequently determine establishment patterns were also investigated. Dispersal distribution throughout the encroachment zone was leptokurtic and dispersal among cover types suggest co-occurring shrub species facilitate dispersal by functioning as bird perches. Interaction of biotic and abiotic factors mediate a complex process of establishment by influencing dispersal, germination and seedling survival to ultimately determine distribution patterns of woody plants in coastal environments

Lokomotive

Set in 1943, 'LOKOMOTIVE' is a World War Two adventure located partially in England but mostly in the Pas de Calais region of France. The action takes place in and around 'La Coupole', the enormous V-2 rocket complex situated near Wizernes-Helfaut which was constructed by the Germans as part of a series of bases intended to launch devastating missile attacks on the United Kingdom. While the story is a work of fiction, it includes many real events and people whose efforts changed the direction of the war in favour of the allies

Interaction of Seed Dispersal and Environmental Filtering Affects Woody Encroachment Patterns in Coastal Grassland

Encroachment of woody plants into grasslands has occurred worldwide and includes coastal ecosystems. This conversion process is mediated by seed dispersal patterns, environmental filtering, and biotic interactions. As spatiotemporally heterogeneous, harsh environments, barrier islands present a unique set of challenges for dispersal and establishment. Environmental conditions act as filters on dispersed seeds, thereby influencing encroachment and distribution patterns. Seldom have patterns of propagule dispersal been considered in the context of woody encroachment. We quantified dispersal and post‐dispersal processes of an encroaching woody population of Morella cerifera relative to directional rate of encroachment and observed distribution patterns on an Atlantic coastal barrier island with strong environmental filtering. We analyzed historic foredune elevation as a proxy for reduced interior environmental stress. The dispersal kernel was leptokurtic, a common characteristic of expanding populations, but rate of encroachment has slowed since 2005. Expansion pattern was related to foredune elevation, which limits encroachment below a threshold elevation. This difference between dispersal kernel behavior and encroachment rate is due to limited availability of suitable habitat for Morella and temporal variability in chlorides during the time of germination. Our results demonstrate that processes mediating seeds and seedling success must be accounted for to better understand establishment patterns of encroaching woody plants

Propuesta de uso de agua de lluvia en el sector, Loma - Shingle Hill de la Isla de San Andrés

El agua lluvia es un recurso que está disponible en cantidad y calidad para el aprovechamiento humano. Este trabajo propone el uso del agua lluvia en el Sector Loma Shingle Hill, San Andrés Isla, Colombia, como alternativa de abastecimiento en las viviendas del sector con la debida participación de la comunidad. De acuerdo con los resultados de la investigación, solo 19 de las 64 viviendas visitadas cuentan con cisternas para la recolección de agua de lluvia como fuente de suministro en combinación con otras fuentes. Las precipitaciones de la zona son suficientes en cantidad y calidad, pero existen limitaciones en el aprovechamiento por la baja capacidad de almacenamiento de las cisternas. El reducido tamaño de muchas viviendas y el elevado costo de inversión inicial imposibilitan la construcción de cisternas grandes. De acuerdo con el IDEAM, entre 1974 y 1998, cayeron 1.894 mm de lluvia anual, cantidad suficiente para abastecer a una población de 934.000 habitantes; pero el aprovechamiento de esta se ha calculado como en un 5%, (94,7 mm). Durante los últimos años, el promedio anual se ha ubicado en 1.900 mm. La condición estacional seca puede llegar a 5 meses. Los meses de Febrero, marzo y abril son tradicionalmente secos; mayo es un mes de transición y desde junio hasta octubre son meses húmedos. Noviembre y diciembre son meses de precipitaciones más moderadas mientras que enero es el mes de transición entre la época húmeda y la seca (Escalona et. al, 2002). No se encontró presencia de Coliformes fecales en el agua que precipita, aunque un estudio reciente elaborado por Coralina en el 2002 indica que el agua de 24 cisternas de todos los estratos, fueron positivas en 21. A esto se suma el taponamiento de los canales de captación, ocasionada por la acumulación de hojas, piedras y otros materiales (Coralina, 2002). En San Andrés Isla de las 19 cisternas con que cuenta el sector Loma – Shingle Hill, a 13 de estas se les hace limpieza y mantenimiento una vez al año y a 4 de ellas dos veces al año. Finalmente este trabajo propone el uso de agua lluvia como una alternativa de abastecimiento en las viviendas del Sector Loma Shingle Hill de la isla de San Andrés, mediante la socialización y posterior entrega de folletos que buscan de alguna manera sensibilizar a los habitantes del sector sobre el uso o aprovechamiento del agua de lluviaTrabajo de grado ( Administrador del Medio Ambiente y de los Recursos Naturales)--Universidad Autónoma de Occidente, 2016PregradoAdministrador(a) Ambienta

Relaxation of Vibrational Excitons in Molecular-Ionic Crystal s Measured by Picosecond Time-Resolved CARS

The decay times of the internal vibrations in K2S04, KCl04, NaN03 and CaC03 single crystals have been measured at different temperature s by picosecond time-resolved CARS. The low temperature experimental data and their temperature dependence are interpreted on the basis of an energy relaxation mechanism, involving two-phonon and higher order decay processes

A systems biology approach to invasive behavior: comparing cancer metastasis and suburban sprawl development

Background Despite constant progress, cancer remains the second leading cause of death in the United States. The ability of tumors to metastasize is central to this dilemma, as many studies demonstrate successful treatment correlating to diagnosis prior to cancer spread. Hence a better understanding of cancer invasiveness and metastasis could provide critical insight. Presentation of the hypothesis We hypothesize that a systems biology-based comparison of cancer invasiveness and suburban sprawl will reveal similarities that are instructive. Testing the hypothesis We compare the structure and behavior of invasive cancer to suburban sprawl development. While these two systems differ vastly in dimension, they appear to adhere to scale-invariant laws consistent with invasive behavior in general. We demonstrate that cancer and sprawl have striking similarities in their natural history, initiating factors, patterns of invasion, vessel distribution and even methods of causing death. Implications of the hypothesis We propose that metastatic cancer and suburban sprawl provide striking analogs in invasive behavior, to the extent that conclusions from one system could be predictive of behavior in the other. We suggest ways in which this model could be used to advance our understanding of cancer biology and treatment