ALBERT

Description: Shavenbaby and Yorkie mediate Hippo signaling to protect adult stem cells from apoptosis Shavenbaby and Yorkie mediate Hippo signaling to protect adult stem cells from apoptosis, Published online: 30 November 2018; doi:10.1038/s41467-018-07569-0 Organ regeneration by stem cells is required to compensate for tissue damage during aging, although how stem cells are maintained in adulthood is poorly understood. Here, the authors show in Drosophila that Shavenbaby interacts with Yorkie, a mediator of Hippo signalling, to ensure adult stem cell survival.

Description: A general analytical model for one-dimensional transient vertical infiltration is presented. The model is based on a combination of the Brooks and Corey soil water retention function and a generalized hydraulic conductivity function. This leads to power law diffusivity and convective term for which the exponents are functions of the inverse of the pore size distribution index. Accordingly, the proposed analytical solution covers many existing realistic models in the literature. The general form of the analytical solution is simple and it expresses implicitly the depth as function of water content and time. It can be used to model infiltration through semi-infinite dry soils with prescribed water content or flux boundary conditions. Some mathematical expressions of practical importance are also derived. The general form solution is useful for comparison between models, validation of numerical solutions and for better understanding the effect of some hydraulic parameters. Based on the analytical expression, a complete inverse procedure which allows the estimation of the hydraulic parameters from water content measurements is presented. This article is protected by copyright. All rights reserved.

Description: In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amazonia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, Jin -- Albert, Loren P -- Lopes, Aline P -- Restrepo-Coupe, Natalia -- Hayek, Matthew -- Wiedemann, Kenia T -- Guan, Kaiyu -- Stark, Scott C -- Christoffersen, Bradley -- Prohaska, Neill -- Tavares, Julia V -- Marostica, Suelen -- Kobayashi, Hideki -- Ferreira, Mauricio L -- Campos, Kleber Silva -- da Silva, Rodrigo -- Brando, Paulo M -- Dye, Dennis G -- Huxman, Travis E -- Huete, Alfredo R -- Nelson, Bruce W -- Saleska, Scott R -- New York, N.Y. -- Science. 2016 Feb 26;351(6276):972-6. doi: 10.1126/science.aad5068.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. jinwu@email.arizona.edu saleska@email.arizona.edu. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. ; Brazil's National Institute for Amazon Research (INPA), Manaus, Amazonas, Brazil. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia. ; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. ; Department of Natural Resources and Environmental Science, University of Illinois at Urbana Champaign, Urbana, IL 61081, USA. Department of Earth System Science, Stanford University, Stanford, CA 94025, USA. ; Department of Forestry, Michigan State University, East Lansing, MI 48824, USA. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. Earth and Environmental Sciences Division, Los Alamos National Lab, Los Alamos, NM 87545, USA. ; Department of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan. ; Centro de Energia Nuclear na Agricultura, University of Sao Paulo, Piracicaba, SP, Brazil. Smart and Intelligent Cities Programme, University Nove de Julho, Sao Paulo, SP, Brazil. ; Department of Environmental Physics, University of Western Para (UFOPA), Santarem, Para, Brazil. ; Instituto de Pesquisa Ambiental da Amazonia (IPAM), Belem, Para, Brazil. Woods Hole Research Center, Falmouth, MA 02450, USA. ; Western Geographic Science Center, U.S. Geological Survey, Flagstaff, AZ 86001, USA. ; Ecology and Evolutionary Biology and Center for Environmental Biology, University of California, Irvine, CA 92629, USA. ; Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26917771" target="_blank"〉PubMed〈/a〉

Description: The lock-in amplifier is often used to study the enhancement of the magneto-optical Kerr effect (MOKE) in the presence of plasmon resonances. In the present work we show that it is possible to investigate such effect replacing the lock-in amplifier by a compensator, filter, and differential amplifier. This allows us to extract the full hysteresis loop in and out of the resonance without the need of a lock-in amplifier. Our results demonstrate these two setups are equivalent to study the enhancement of the transversal MOKE (T-MOKE) in magnetoplasmonic systems.

Description: In the US, there is growing interest in producing more beef from cattle raised in exclusively pasture-based systems, rather than grain-finishing feedlot systems, due to the perception that it is more environmentally sustainable. Yet existing understanding of the environmental impacts of exclusively pasture-based systems is limited by a lack of clarity about cattle herd dynamics. We model a nationwide transition from grain- to grass-finishing systems using demographics of present-day beef cattle. In order to produce the same quantity of beef as the present-day system, we find that a nationwide shift to exclusively grass-fed beef would require increasing the national cattle herd from 77 to 100 million cattle, an increase of 30%. We also find that the current pastureland grass resource can support only 27% of the current beef supply (27 million cattle), an amount 30% smaller than prior estimates. If grass-fed systems include cropland-raised forage, a definition that conforms to typ...

Description: The mixed siliciclastic/carbonate sediments of Baffin Bay, Texas, provide a record of the evolution of the Bay for the last 10 ka. Flooding surfaces at 8 ka and 5.5 ka provided an a priori separation of sediments in a core into three groups. Discriminant analysis and interpretation of species composition of the foraminifera from these groups indicated a progression from deltaic to open-bay to hypersaline environments. This traditional paleoecological analysis, however, does not utilize the information available in the relative abundance distribution (RAD) within each community. An approach capable of assessing within community change is provided by S (species richness), H (Shannon information function) and E (evenness) analysis. Using this approach not only can communities be designated without a priori assumptions and environments identified easily, but also the RAD within each community can be evaluated, providing a record of community growth, decline or stasis with time. Stasis, or the ecological balance of nature, is mathematically defined as an equilibrium between S and E such that diversity (H) remains constant with time. This stasis requires that, as the number of individuals (N) gets larger with time, the value of H remains constant. Thus, at stasis a regression between H versus lnN will have a 0 value for the regression coefficient (β 1H ), here termed the Relative Abundance Distribution Index, RADI. A positive value of RADI indicates community growth, a negative value indicates community decline. In the Baffin Bay core 6, communities were identified from 46 samples using SHE analysis. At ~9 ka the RADI was positive, indicating the growth of a normal marine community with a high S. A second community, still largely normal marine but with a slightly negative RADI, formed at ~8 ka. Beginning at ~6.4 ka, the 3 rd and 4 th marginal marine communities with highly negative RADIs formed, indicating a sharp decline for ~1 ka during the formation of Padre Island, which may have taken ~1000 years. At ~5 ka the 5 th and 6 th marginal marine communities were established with RADIs indicating a prolonged period of stasis. The 5 th community was dominated by Elphidium with a high percentage of miliolids. The 6 th community, established at ~2 ka, was dominated by Ammonia and a moderate percentage of miliolids. These last two communities, both at stasis, were apparently responding to changes in salinity brought on by changes in rainfall.

Description: Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis, and biotic variation in canopy photosynthetic light-use efficiency associated with changes in the parameters themselves. Our fitted model was able to explain most of the variability in GEP at hourly (R 2 =0.77) to inter-annual (R 2 =0.80) timescales. At hourly timescales, we found that 75% of observed GEP variability could be attributed to environmental variability. When aggregating GEP to the longer timescales (daily, monthly, and yearly), however, environmental variation explained progressively less GEP variability: at monthly timescales, it explained only 3%, much less than biotic variation in canopy photosynthetic light-use efficiency, which accounted for 63%. These results challenge modeling approaches that assume GEP is primarily controlled by the environment at both short and long timescales. Our approach distinguishing biotic from environmental variability can help to resolve debates about environmental limitations to tropical forest photosynthesis. For example, we found that biotically regulated canopy photosynthetic light-use efficiency (associated with leaf phenology) increased with sunlight during dry seasons (consistent with light but not water limitation of canopy development), but that realized GEP was nonetheless lower relative to its potential efficiency during dry than wet seasons (consistent with water limitation of photosynthesis in given assemblages of leaves). This work highlights the importance of accounting for differential regulation of GEP at different timescales, and of identifying the underlying feedbacks and adaptive mechanisms.