Where are the tropical plants? A call for better inclusion of tropical plants in studies investigating and predicting the effects of climate change

Tropical plant species are systematically underrepresented in large-scale analyses or synthesis looking at the potential effects of global climate change.  The reason being that we simply don’t know enough about the distributions and ecologies of most tropical plant species to predict their fate under climate change. This gaping hole in our knowledge is extremely worrisome given the high diversity of tropical plants, the crucial roles that they play in supporting global diversity and ecosystem function, and the elevated threats that climate change may pose to tropical species in general.  </p

Seismic Response of Shallow Underground Structures in Dense Urban Environments

Shallow underground structures used for public transportation are a key component of sustainable cities. In dense urban environments, underground structures are often built near tall buildings. Although such buildings have the potential to alter ground motions in their vicinity and transmit significant forces to adjacent underground structures during earthquakes, these impacts are not well understood. Centrifuge tests were performed to evaluate seismic interactions between an underground structure, soil, and an adjacent mid- to high-rise building. The seismic response of a braced, temporary excavation and a permanent, cut-and-cover box structure in medium dense, dry sand is measured independently first and then when adjacent to mid and highrise buildings. The data from these tests serve two purposes: first, to better understand seismic soil-structure-underground structure-interaction (SSUSI), and second, to calibrate and improve numerical models. In each centrifuge experiment, the seismic performance of the underground structure was investigated in terms of key design parameters, such as seismic lateral earth pressures, racking displacements, and bending moments using tactile pressure sensors, linear potentiometers, accelerometers, and strain gauges. Centrifuge measurements indicate that both tunnel and excavation racking versus flexibility ratios followed the expected patterns when compared to the available design procedures for an isolated underground structure (e.g., NCHRP 611). The experimental results also indicate that the presence of an adjacent mid to highrise building slightly reduces racking displacements of the underground structure, but increases seismic lateral earth pressures. Bending moments along the excavation walls and axial forces on the struts are also shown to notably increase with the presence of an adjacent tall building. The dynamic lateral thrust acting on the sides of the underground structures is shown to roughly follow the adjacent building’s base shear in amplitude and frequency content. Based on the observed results, mechanisms of interaction among the tall building, soil, and an adjacent permanent or temporary underground structure are explored in terms of: 1) the tall building’s inertial forces, 2) the foundation’s kinematic constraints, and 3) the building’s added confinement

Tactile Pressure Sensor Calibration Methods and Data Analysis for Geotechnical Centrifuge Modeling

When investigating the seismic response of buried structures in geotechnical experiments, a reliable measure of dynamic earth pressure is necessary. Tactile pressure sensors are flexible, thin sheets containing a matrix of sensels (sensors), allowing them to measure pressure distributions with minimal intrusion and avoid soil arching effects. Each of the sensor's sensels can record pressure at high sampling rates (e.g., up to 20,000 samples/second).Calibrating tactile pressure sensors for use in dynamic centrifuge modeling with granular materials has been challenging in the past. In particular, they have been unable to capture the full amplitude content of a dynamic signal at high frequencies. This is due to the low sampling rate of older sensor models (leading to signal aliasing) and the sensor's own frequency response. In this thesis, a dynamic calibration procedure is proposed and evaluated to correct for the tactile sensor's frequency response. Further, different static calibration procedures are compared and evaluated in this study.The dynamic response of tactile pressure sensors was characterized by loading them with sine-waves of different frequencies using a controlled loading machine at the University of Colorado, Boulder. A transfer function was calculated to relate the pressure sensor's signal to the reference load cell recording as a function of frequency. A digital filter was developed based on this transfer function and applied to pressure sensor recordings to recover the original, high frequency signal. The reliability of the proposed dynamic calibration procedure was then tested through a series of blind dynamic tests with the loading machine and dynamic centrifuge tests with water.Two methods of static calibration were explored and compared in this study: (1) loading of the sensor with a controlled loading machine; and (2) placing the sensor at the bottom of a centrifuge container covered with the test sand and spun to different g-levels. Calibration results from each method were applied to sensor recordings of static lateral earth pressure on a tunnel wall during a centrifuge model test. For the particular tactile sensor tested here, static calibration with the loading machine yielded better comparisons with theoretical estimates of lateral earth pressure

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Idiopathic Radiation Recall Dermatitis Developing Nine Months after Cessation of Cisplatin Therapy in Treatment of Squamous Cell Carcinoma of the Tonsil

To report on a suspected case of idiopathic radiation recall dermatitis in an individual nine months after radiation and chemotherapy treatment of squamous cell carcinoma of the right tonsil. Radiation recall dermatitis is the development of a reaction in a previously irradiated area of skin after the administration of an aggravating medication. A review of the literature revealed several cases of radiation recall dermatitis that occur following radiation therapy and the institution of chemotherapy. Other medications have also been implicated in radiation recall dermatitis; however, this patient has not started any new medications since completion of his combined therapy. The patient developed this skin reaction in a distribution pattern identical to the area that received the highest radiation dose suggesting a possible link between radiation recall dermatitis and radiation dose. Radiation recall dermatitis is a reaction that is typically seen shortly after the reinstitution of chemotherapy during radiation therapy. This case illustrates that other medical etiologies are possible and suggests a relationship between radiation recall dermatitis and the total radiation dose an area receives

Ecosystem Services and U.S. Stormwater Planning: An Approach for Improving Urban Stormwater Decisions

Green stormwater infrastructure (GI) is gaining traction as a viable complement to traditional “gray” infrastructure in cities across the United States. As cities struggle with decisions to replace deteriorating stormwater infrastructure in the face of looming issues such as population growth and climate change, GI may offer a costeffective, efficient, and sustainable approach. However, decision makers confront challenges when integrating GI within city plans, including uncertainties around GI capacity and maintenance, resistance to collaboration across city governance, increasingly inflexible financing, accounting practices that do not incorporate the multiple values of GI, and difficulties in incorporating ecological infrastructure into stormwater management. This paper presents an ecosystem services framework for assessing the context-specific needs of decision makers, while considering the strengths and limitations of GI use in urban stormwater management. We describe multiple dimensions of the planning system, identify points of intervention, and illustrate two applications of our framework – Durham, North Carolina and Portland, Oregon (USA). In these case studies, we apply our ecosystem services framework to explicitly consider tradeoffs to assist planning professionals who are considering implementation of GI. We conclude by offering a research agenda that explores opportunities for further evaluations of GI design, implementation, and maintenance in cities

Mouse frontal cortex mediates additive multisensory decisions

The brain can combine auditory and visual information to localize objects. However, the cortical substrates underlying audiovisual integration remain uncertain. Here, we show that mouse frontal cortex combines auditory and visual evidence; that this combination is additive, mirroring behavior; and that it evolves with learning. We trained mice in an audiovisual localization task. Inactivating frontal cortex impaired responses to either sensory modality, while inactivating visual or parietal cortex affected only visual stimuli. Recordings from >14,000 neurons indicated that after task learning, activity in the anterior part of frontal area MOs (secondary motor cortex) additively encodes visual and auditory signals, consistent with the mice's behavioral strategy. An accumulator model applied to these sensory representations reproduced the observed choices and reaction times. These results suggest that frontal cortex adapts through learning to combine evidence across sensory cortices, providing a signal that is transformed into a binary decision by a downstream accumulator

Network design for mesoscale inversions of CO2 sources and sinks

International audienceRecent instrumental deployments of regional observation networks of atmospheric CO2 mixing ratios have been used to constrain carbon sources and sinks using inversion methodologies. In this study, we performed sensitivity experiments using observation sites from the Mid Continent Intensive experiment to evaluate the required spatial density and locations of CO2 concentration towers based on flux corrections and error reduction analysis. In addition, we investigated the impact of prior flux error structures with different correlation lengths and biome information. We show here that, while the regional carbon balance converged to similar annual estimates using only two concentration towers over the region, additional sites were necessary to retrieve the spatial flux distribution of our reference case (using the entire network of eight towers). Local flux corrections required the presence of observation sites in their vicinity, suggesting that each tower was only able to retrieve major corrections within a hundred of kilometres around, despite the introduction of spatial correlation lengths (~100 to 300 km) in the prior flux errors. We then quantified and evaluated the impact of the spatial correlations in the prior flux errors by estimating the improvement in the CO2 model-data mismatch of the towers not included in the inversion. The overall gain across the domain increased with the correlation length, up to 300 km, including both biome-related and non-biome-related structures. However, the spatial variability at smaller scales was not improved. We conclude that the placement of observation towers around major sources and sinks is critical for regional-scale inversions in order to obtain reliable flux distributions in space. Sparser networks seem sufficient to assess the overall regional carbon budget with the support of flux error correlations, indicating that regional signals can be recovered using hourly mixing ratios. However, the smaller spatial structures in the posterior fluxes are highly constrained by assumed prior flux error correlation lengths, with no significant improvement at only a few hundreds of kilometres away from the observation sites