The Pressure Is On – Epiphyte Water-Relations Altered Under Elevated CO2

Vascular epiphytes are a major biomass component of forests across the globe and they contribute to 9% of global vascular plant diversity. To improve our understanding of the whole-plant response of epiphytes to future climate change, we investigated for the first time both individual and combined effects of elevated CO2 (560 ppm) and light on the physiology and growth of two epiphyte species [Tillandsia brachycaulos (CAM) and Phlebodium aureum (C3)] grown for 272 days under controlled conditions. We found that under elevated CO2 the difference in water loss between the light (650 μmol m-2s-1) and shade (130 μmol m-2s-1) treatment was strongly reduced. Stomatal conductance (gs) decreased under elevated CO2, resulting in an approximate 40–45% reduction in water loss over a 24 h day/night period under high light and high CO2 conditions. Under lower light conditions water loss was reduced by approximately 20% for the CAM bromeliad under elevated CO2 and increased by approximately 126% for the C3 fern. Diurnal changes in leaf turgor and water loss rates correlated strong positively under ambient CO2 (400 ppm) and high light conditions. Future predicted increases in atmospheric CO2 are likely to alter plant water-relations in epiphytes, thus reducing the canopy cooling potential of epiphytes to future increases in temperature

Oil Burst

Oil Burst is a photo painting from Maggie Cardelus's most recent body of work called Split Sun, which revisits American landscape photography using crude oil as a painting medium in order to create evocative works that suggest a new more problematic American Identity brought by the burning and spilling of fossil fuels

Oil Storm

Oil Storm is part of a larger body of work by Maggie Cardelus called Split Sun. It consists of 16 photo paintings. Split Sun revisits American landscape photography using crude oil as a painting medium in order to create evocative works that suggest a new more problematic American Identity brought on by the burning and spilling of fossil fuels

Ocean Oil Pour

Ocean Oil Pour is part of Maggie Cardeuls' 2019 body of work called Split sun which revisits American Landscape Photography using crude oil as a painting medium in order to create evocative works that suggest a new more problematic American Identity brought by the burning and spilling of fossil fuels

Refining Reputation Systems applying Subjective Logic

A reputation system computes and publishes reputation scores regarding any kind of entity (e.g. services or goods) within a community. Since the explosion of Internet the quantity of opinions regarding a particular item has increased dramatically, so the relevance of reputation systems is greater than ever. Nevertheless, experience shows that information held in a reputation centre is not fully reliable. The first challenge is to evaluate the trustfulness of the information. Secondly, a user who is looking for advice would prefer to give more importance to the opinions from people with a similar profile (age, gender, etc.) in order to get a customized advice. This work describes a framework that combines these two challenges in a single model. A user who is looking for advice will get a customized score for an entity based on how other users have reviewed this particular entity. In addition, the system considers the reputation of the reviewers and matches the similarity of each reviewer with the user looking for advice. The tool used to develop this model is subjective logic, a kind of probabilistic logic that allows expressing uncertainty in absence of explicit belief. Finally, we test the model with some invented scenarios to validate it.Outgoin

Refining Reputation Systems applying Subjective Logic

A reputation system computes and publishes reputation scores regarding any kind of entity (e.g. services or goods) within a community. Since the explosion of Internet the quantity of opinions regarding a particular item has increased dramatically, so the relevance of reputation systems is greater than ever. Nevertheless, experience shows that information held in a reputation centre is not fully reliable. The first challenge is to evaluate the trustfulness of the information. Secondly, a user who is looking for advice would prefer to give more importance to the opinions from people with a similar profile (age, gender, etc.) in order to get a customized advice. This work describes a framework that combines these two challenges in a single model. A user who is looking for advice will get a customized score for an entity based on how other users have reviewed this particular entity. In addition, the system considers the reputation of the reviewers and matches the similarity of each reviewer with the user looking for advice. The tool used to develop this model is subjective logic, a kind of probabilistic logic that allows expressing uncertainty in absence of explicit belief. Finally, we test the model with some invented scenarios to validate it.Outgoin

Distribution and abundance of vascular epiphytes in tropical wet forests: A multi-scale approach

I examined the distribution, abundance and diversity of vascular epiphytes at three scales: within individual tree crowns, between tree species and along an altitudinal gradient. Within individual tree crowns and between species, I examined the effects of microclimate, tree characteristics, tree species, season and leaf phenology on the distribution, abundance and diversity of epiphytes in two tree species, Hyeronima alchomeoides and Lecythis ampla, at La Selva Biological Station in Costa Rica. The microenvironmental conditions within Hyeronima crowns were more homogeneous than Lecythis, which had a significantly greater PFD reaching the canopy during the dry season than Hyeronima and a doubling of PFD levels when it was deciduous. There was little overlap of epiphyte species among individuals within and between tree species and Hyeronima had significantly greater abundance of epiphytes than Lecythis. I ran a Canonical Correspondence Analysis on the epiphyte species richness and abundance with the microenvironmental and tree characteristics which explained only 12.4% of epiphyte distributions. High diversity, combined with the lack of community structure, suggest that tropical rainforest canopy communities are not in equilibrium and that this high diversity is maintained by a non-equilibrium mechanism such as intermediate disturbance or dispersal limitation, or perhaps by an equilibrium mechanism such as resource partitioning. ^ To assess diversity, distribution and abundance of vascular epiphytes along a contiguous old-growth elevational gradient in Costa Rica, I collected vascular epiphytes at five elevations, 2600m, 2000m, 1500m, 1000m, and 500m. All epiphytes were sampled in eight contiguous 0.5m x 0.5m quadrats along two lower branches in ten canopy trees at 2000m, 1600m and 1000m, nine at 500m and five at 2500m. I identified a total of 527 species of epiphytes in 121 genera in 49 families. The Pteridophytes were the most diverse group, 129 species, followed by Orchidaceae, 118 species. Cloud forest at 1000m was the most species rich site. ^ I recommend a rapid, standardized protocol to assess epiphyte diversity in situ. Two branches at differing heights in the canopy should be assessed to maximize microclimatic variation. The transects should be subdivided into quadrats which allows reference for distribution such as distance from the trunk, branch height, diameter, azimuth and angle.