Resource Mediated Competition of two South Texas Natives: _Acacia berlandieri_ and _Trichloris pluriflora_

*Background/Question/Methods* 
_Acacia berlandieri_, an early-successional C~3~ woody shrub legume, and _Trichloris pluriflora_, a late-successional/climax C~4~ mid-tall grass, reside in similar habitats and have both been documented in Texas for over 150 years. This study examines the resource mediated above and below ground competition within and between these species, which may illuminate some of the dynamics involved in the encroachment of woody shrub species into the former grasslands. These species, started from seed, were grown outdoors (5 replicates/treatment) using sandy clay loam soil in plastic lined 15×15 cm pots for 155 days and watered daily. Half of these pots received 12.5% Hoagland’s solution as a nutrient source. Growth measurements were taken 3 times, after a 72 day establishment period and prior to harvest. The plants were then harvested intact, dried at 60°C, and above and below ground dry mass for each individual plant was separated. The roots were ashed at 650°C and measurements were taken for the above and below ground biomass. 

*Results/Conclusions* 
The growth parameters of _Acacia berlandieri_, basal diameter, height, and number of leaves increased with density (P = 0.0024, P < 0.0001, and P < 0.0001), when grown in competition with _Trichloris pluriflora_, using the densities of 1/3, 2/2. 3/1, and 4/0 _Acacia/Trichloris_ plants/pot. None of these growth parameters for _A. berlandieri_ had an effect on the variables of density, nutrients or and their interaction (P > 0.0500), when grown alone with densities of 1, 2, and 4 plants/pot. The growth parameters of _T. pluriflora_, culms and height decreased with density (P = 0.0077 and P = 0.0006), when grown in competition with _A. berlandieri_, using densities of 1/3, 2/2. 3/1, and 4/0 _Trichloris/Acacia_ plants/pot. The culms, tillers, and height of _T. pluriflora_, when grown alone with densities of 1, 2, 4, and 8 plants/pot, decreased with density (P < 0.0001, P = 0.0312, and P < 0.0001). The measurement parameters of harvested _A. berlandieri_, above ground biomass and ash-free root biomass increased with density (P = 0.0463 and P = 0.0389), when grown in competition with _T. pluriflora_. The root biomass of harvested _A. berlandieri_, grown alone, decreased with the interaction of density and nutrients (P = 0.0068). The total plant dry mass, above ground biomass, root dry mass, and root dry mass of harvested _T. pluriflora_, grown in competition with _A. berlandieri_, decreased with density (P < 0.0001, P < 0.0001, P = 0.0235, and P = 0.0145). These same measurement parameters of harvested _T. pluriflora_, grown alone, increased with density (P < 0.0001 for all four). The addition of nutrients had no effect on the growth or harvest of _A. berlandieri_ and _T. pluriflora_ for either intra- or interspecific competition. Instead, density appeared to be the driving force for the competition between and among these two species for both growth and harvest. Although woody shrub and grassland interactions should be mediated by resource availability, that was not the case in this study. Clearly, density is an important variable involved in the disappearance of the grasslands

Care Planning and Review for Looked After Children: Fifteen Years of Slow Progress?

This Critical Commentary reviews progress in research into planning and reviewing for children in care in England and Wales since the publication of two major studies in the late 1990s (roughly coinciding with the New Labour period). It briefly considers the changing context of law, regulation and guidance and the aims and objectives of the care planning and review system. It then reviews the limited research literature available, in relation to a series of key topics. Consideration is also given to guides for children and practitioners on the subject. The commentary concludes by suggesting that this is an area in which research has failed to keep pace with changes in policy and practice, and recommends a more systematic approach

Nano-scale superhydrophobicity: suppression of protein adsorption and promotion of flow-induced detachment

Wall adsorption is a common problem in microfluidic devices, particularly when proteins are used. Here we show how superhydrophobic surfaces can be used to reduce protein adsorption and to promote desorption. Hydrophobic surfaces, both smooth and having high surface roughness of varying length scales (to generate superhydrophobicity), were incubated in protein solution. The samples were then exposed to flow shear in a device designed to simulate a microfluidic environment. Results show that a similar amount of protein adsorbed onto smooth and nanometer-scale rough surfaces, although a greater amount was found to adsorb onto superhydrophobic surfaces with micrometer scale roughness. Exposure to flow shear removed a considerably larger proportion of adsorbed protein from the superhydrophobic surfaces than from the smooth ones, with almost all of the protein being removed from some nanoscale surfaces. This type of surface may therefore be useful in environments, such as microfluidics, where protein sticking is a problem and fluid flow is present. Possible mechanisms that explain the behaviour are discussed, including decreased contact between protein and surface and greater shear stress due to interfacial slip between the superhydrophobic surface and the liquid

Surgery Versus Radiation for High-risk Prostate Cancer: The Fight Continues. But Is It Time To Call a Draw and Reach Consensus?

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Collimated, single-pass atom source from a pulsed alkali metal dispenser for laser-cooling experiments

We have developed an improved scheme for loading atoms into a magneto-optical trap (MOT) from a directed alkali metal dispenser in < 10^-10 torr ultra-high vacuum conditions. A current-driven dispenser was surrounded with a cold absorbing "shroud" held at < 0 C, pumping rubidium atoms not directed into the MOT. This nearly eliminates background alkali atoms and reduces the detrimental rise in pressure normally associated with these devices. The system can be well-described as a current-controlled, rapidly-switched, two-temperature thermal beam, and was used to load a MOT with 3 x 10^8 atoms.Comment: 5 pages, 4 figure

Perceptual learning shapes multisensory causal inference via two distinct mechanisms

To accurately represent the environment, our brains must integrate sensory signals from a common source while segregating those from independent sources. A reasonable strategy for performing this task is to restrict integration to cues that coincide in space and time. However, because multisensory signals are subject to differential transmission and processing delays, the brain must retain a degree of tolerance for temporal discrepancies. Recent research suggests that the width of this 'temporal binding window' can be reduced through perceptual learning, however, little is known about the mechanisms underlying these experience-dependent effects. Here, in separate experiments, we measure the temporal and spatial binding windows of human participants before and after training on an audiovisual temporal discrimination task. We show that training leads to two distinct effects on multisensory integration in the form of (i) a specific narrowing of the temporal binding window that does not transfer to spatial binding and (ii) a general reduction in the magnitude of crossmodal interactions across all spatiotemporal disparities. These effects arise naturally from a Bayesian model of causal inference in which learning improves the precision of audiovisual timing estimation, whilst concomitantly decreasing the prior expectation that stimuli emanate from a common source