3,055 research outputs found
Integrated Pest Management Manual for Greenhouses
The original definition of Integrated Pest Management (IPM) was introduced by Stern et al. in 1959 as Integrated Control. It was defined as applied pest control which combines and integrates biological and chemical control (Stern et al. 1959). Entomologists began exploring insect management alternatives to reduce reliance on insecticides in the 1950’s after resistance and pest resurgence in agriculture was first noted. Today, the European Union follows a definition of IPM largely inspired from the definition given by the Food and Agriculture Organization of the United Nations (FAO) (Barzman et al. 2015). Integrated Pest Management means the careful consideration of all available pest control techniques and subsequent integration of appropriate measures that discourage the development of pest populations and keep pesticides and other interventions to levels that are economically justified and reduce or minimize risks to human health and the environment. IPM emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms (FAO.org, 2019). The goal of IPM is a holistic and synergistic approach. It integrates preventive methods using different approaches. It focuses on biological, agronomic, mechanical, and physical principles, only resorting to selective pesticide usage when other tools are not successful (Barzman et al. 2015).
Greenhouses growing plants for research and development efforts have high plant densities with non-stop single crop production systems. This characteristic alone encourages the spread of pests. Furthermore, well fertilized and irrigated crops are often more sensitive to outbreaks of pests than outdoor crops (Gullino et al., 2002). While agronomic crops are the target of many pests, the main pests in a greenhouse environment are sucking pests such as whiteflies, aphids, thrips and mites. These are typically polyphagous insects, and are generally more problematic in greenhouses than in the field because of the ideal warm and moist protected environment, as well as the isolation from their natural enemies (Tian, 2000). These arthropods can develop and reproduce successfully throughout the year without hibernation under controlled conditions, producing more generations per year and causing more serious damage than under open field conditions (Tian, 2000). The greenhouse “acceptance threshold” is very low on agronomic crops with a R&D status. Nevertheless, integrated pest management within a controlled environment follows the same principles and management strategies to crops grown on fields. The following will be discussed: pest biology and identification, scouting and monitoring, cultural practices, biological control and chemical control
Thermodynamics of Ion Separation by Electrosorption
We present a simple, top-down approach for the calculation of minimum energy
consumption of electrosorptive ion separation using variational form of the
(Gibbs) free energy. We focus and expand on the case of electrostatic
capacitive deionization (CDI), and the theoretical framework is independent of
details of the double-layer charge distribution and is applicable to any
thermodynamically consistent model, such as the Gouy-Chapman-Stern (GCS) and
modified Donnan (mD) models. We demonstrate that, under certain assumptions,
the minimum required electric work energy is indeed equivalent to the free
energy of separation. Using the theory, we define the thermodynamic efficiency
of CDI. We explore the thermodynamic efficiency of current experimental CDI
systems and show that these are currently very low, less than 1% for most
existing systems. We applied this knowledge and constructed and operated a CDI
cell to show that judicious selection of the materials, geometry, and process
parameters can be used to achieve a 9% thermodynamic efficiency (4.6 kT energy
per removed ion). This relatively high value is, to our knowledge, by far the
highest thermodynamic efficiency ever demonstrated for CDI. We hypothesize that
efficiency can be further improved by further reduction of CDI cell series
resistances and optimization of operational parameters
Gene expression of endangered coral (Orbicella spp.) in flower garden banks National Marine Sanctuary after Hurricane Harvey
About 190 km south of the Texas–Louisiana border, the East and West Flower Garden Banks (FGB) have maintained > 50% coral cover with infrequent and minor incidents of disease or bleaching since monitoring began in the 1970s. However, a mortality event, affecting 5.6 ha (2.6% of the area) of the East FGB, occurred in late July 2016 and coincided with storm-generated freshwater runoff extending offshore and over the reef system. To capture the immediate effects of storm-driven freshwater runoff on coral and symbiont physiology, we leveraged the heavy rainfall associated with Hurricane Harvey in late August 2017 by sampling FGB corals at two time points: September 2017, when surface water salinity was reduced (∼34 ppt); and 1 month later when salinity had returned to typical levels (∼36 ppt in October 2017). Tissue samples (N = 47) collected midday were immediately preserved for gene expression profiling from two congeneric coral species (Orbicella faveolata and Orbicella franksi) from the East and West FGB to determine the physiological consequences of storm-derived runoff. In the coral, differences between host species and sampling time points accounted for the majority of differentially expressed genes. Gene ontology enrichment for genes differentially expressed immediately after Hurricane Harvey indicated increases in cellular oxidative stress responses. Although tissue loss was not observed on FGB reefs following Hurricane Harvey, our results suggest that poor water quality following this storm caused FGB corals to experience sub-lethal stress. We also found dramatic expression differences across sampling time points in the coral’s algal symbiont, Breviolum minutum. Some of these differentially expressed genes may be involved in the symbionts’ response to changing environments, including a group of differentially expressed post-transcriptional RNA modification genes. In this study, we cannot disentangle the effects of reduced salinity from the collection time point, so these expression patterns could also be related to seasonality. These findings highlight the urgent need for continued monitoring of these reef systems to establish a baseline for gene expression of healthy corals in the FGB system across seasons, as well as the need for integrated solutions to manage stormwater runoff in the Gulf of Mexico.https://www.frontiersin.org/articles/10.3389/fmars.2019.00672/fullPublished versionPublished versio
Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions
We have created a quantum degenerate Bose-Fermi mixture of 23Na and 40K with
widely tunable interactions via broad interspecies Feshbach resonances. Twenty
Feshbach resonances between 23Na and 40K were identified. The large and
negative triplet background scattering length between 23Na and 40K causes a
sharp enhancement of the fermion density in the presence of a Bose condensate.
As explained via the asymptotic bound-state model (ABM), this strong background
scattering leads to a series of wide Feshbach resonances observed at low
magnetic fields. Our work opens up the prospect to create chemically stable,
fermionic ground state molecules of 23Na-40K where strong, long-range dipolar
interactions will set the dominant energy scale
On the Performance Limits of Map-Aware Localization
Establishing bounds on the accuracy achievable by localization techniques represents a fundamental technical issue. Bounds on localization accuracy have been derived for cases in which the position of an agent is estimated on the basis of a set of observations and, possibly, of some a priori information related to them (e.g., information about anchor positions and properties of the communication channel). In this paper, new bounds are derived under the assumption that the localization system is map-aware, i.e., it can benefit not only from the availability of observations, but also from the a priori knowledge provided by the map of the environment where it operates. Our results show that: a) map-aware estimation accuracy can be related to some features of the map (e.g., its shape and area) even though, in general, the relation is complicated; b) maps are really useful in the presence of some combination of low SNRs and specific geometrical features of the map (e.g., the size of obstructions); c) in most cases, there is no need of refined maps since additional details do not improve estimation accuracy.United States. Air Force Office of Scientific Research (Grant FA9550-12-0287)United States. Office of Naval Research (Grant N00014-11-1-0397)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologie
ATPase activity in glial cells and in neuronal perikarya of rat cerebral cortex during early postnatal development 1
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65822/1/j.1471-4159.1972.tb01365.x.pd
Structural and functional, empirical and modeled connectivity in the cerebral cortex of the rat
[EN] Connectomics data from animal models provide an invaluable opportunity to reveal the complex interplay between structure and function in the mammalian brain. In this work, we investigate the relationship between structural and functional connectivity in the rat brain cortex using a directed anatomical network generated from a carefully curated meta-analysis of published tracing data, along with resting-state functional MRI data obtained from a group of 14 anesthetized Wistar rats. We found a high correspondence between the strength of functional connections, measured as blood oxygen level dependent (BOLD) signal correlations between cortical regions, and the weight of the corresponding anatomical links in the connectome graph (maximum Spearman rank-order correlation rho = 0.48). At the network-level, regions belonging to the same functionally defined community tend to form more mutual weighted connections between each other compared to regions located in different communities. We further found that functional communities in resting-state networks are enriched in densely connected anatomical motifs. Importantly, these higher-order structural subgraphs cannot be explained by lower-order topological properties, suggesting that dense structural patterns support functional associations in the resting brain. Simulations of brain-wide resting-state activity based on neural mass models implemented on the empirical rat anatomical connectome demonstrated high correlation between the simulated and the measured functional connectivity (maximum Pearson correlation rho = 0: 53), further suggesting that the topology of structural connections plays an important role in shaping functional cortical networks.This work was supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds under grants BFU2015-64380-C2-1-R (S.C) and BFU2015-64380-C2-2-R (D.M.) and EU Horizon 2020 Program 668863-SyBil-AA grant (S.C.). S.C. acknowledges financial support from the Spanish State Research Agency, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (ref. SEV-2013-0317). A. D.-P., was supported by grant FPU13/01475 from the Spanish Ministerio de Educacion, Cultura y Deporte (MECD). O.S. acknowledges support by the J.S. McDonnell Foundation (#220020387) and the National Institutes of Health (NIH R01 AT009036-01). We are also grateful to Andrea Avena-Koenigsberger and Begona Fernandez for their technical support.Díaz-Parra, A.; Osborn, Z.; Canals Gamoneda, S.; Moratal, D.; Sporns, O. (2017). Structural and functional, empirical and modeled connectivity in the cerebral cortex of the rat. NeuroImage. 159:170-184. https://doi.org/10.1016/j.neuroimage.2017.07.046S17018415
THE EARLY POST-NATAL DEVELOPMENT OF THE NEURONAL LYSOSOME 1
The hydrolysis of p -nitrophenyl-2-acetamido-2-deoxy-Β-d-gluco-(I) and Β-d-galacto-pyranoside (II) and of p -nitrophenyl-Α-d-mannopyranoside (III) by neuronal cell bodies and glial cells isolated from the cerebral cortex of 18-day-old or adult rats was found to be equally efficient, with relative ratios of hydrolysis for I, II and III of approximately 10:1:0.5 in both cell types and at both ages. Homogenates of the neuronal cell bodies obtained from cerebral cortices of 3-, 8-, 12-, 18- and 32-day-old rats were subjected to differential centrifugation and the subcellular localization of N -acetyl-Β-d-glucosaminidase (EC 3.2.1.30) hydrolysing (I)] was compared to that of the mitochondrial marker, succinate-INT- oxidoreductase (EC 1.3.99.1). A fraction in which N -acetyl-Β-d-glucosaminidase exhibited maximal specific activity could be isolated at all ages, an observation indicating that the potential for active hydrolytic performance is incorporated into the neuronal lysosome very early post-natally. The specific activities of N -acetyl-Β-d-glucosaminidase and succinate- INT-oxidoreductase reached their respective maxima at widely different times postnatally: at 10–12 days for the mitochondrial enzyme and at about 18 days for the glycosidase, a difference suggesting that in the cortical neuron lysosomes and mitochondria develop out of step. The mitochondrial, lysosomal and microsomal fractions obtained by differential centrifugation were subjected to equilibrium density centrifugation and the presence of two populations of N -acetyl-Β-d-glucosaminidase-bearing particles was demonstrated. Although their presence was readily apparent in the neurons from 8- and 12-day old brains, it was difficult to discern their presence in the neurons from the 3- and the 18-day-old brains. In 8-day-old brains gradient fractions obtained from neurons containing N -acetyl-Β-d-glucosaminidase of a specific activity up to 8-fold higher than that of the enzyme in the original neuronal homogenate were examined by electron microscopy and the concentration of numerous lysosomes and derivative bodies in these fractions was verified. Our present study demonstrates the capability of the immature and developing neuron to tightly couple the pace of its degradative processes to that of its highly efficient and highly selective synthetic activities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66318/1/j.1471-4159.1972.tb01312.x.pd
Advances in Plant Virus Evolution: Translating Evolutionary Insights into Better Disease Management
Recent studies in plant virus evolution are revealing that genetic
structure and behavior of virus and viroid populations can explain
important pathogenic properties of these agents, such as host resistance
breakdown, disease severity, and host shifting, among others.
Genetic variation is essential for the survival of organisms. The
exploration of how these subcellular parasites generate and maintain
a certain frequency of mutations at the intra- and inter-host
levels is revealing novel molecular virus–plant interactions. They
emphasize the role of host environment in the dynamic genetic
composition of virus populations. Functional genomics has identified
host factors that are transcriptionally altered after virus infections.
The analyses of these data by means of systems biology
approaches are uncovering critical plant genes specifically targeted
by viruses during host adaptation. Also, a next-generation resequencing
approach of a whole virus genome is opening new
avenues to study virus recombination and the relationships between
intra-host virus composition and pathogenesis. Altogether, the
analyzed data indicate that systematic disruption of some specific
parameters of evolving virus populations could lead to more efficient
ways of disease prevention, eradication, or tolerable virus–plant
coexistence.SD was supported by the NJ Agricultural Experiment Station. SFE was supported by grants from the Spanish Ministerio de Ciencia e Innovación (BFU2009-06993) and Generalitat Valenciana (PROMETEO2010/019). Work on CTV was supported by funding from USDA grants 2003-34399-13764 and 2005-34399-16070 to ZX. Work on BNYVV was funded by The Minnesota-North Dakota Research and Education Board, and The Beet Sugar Development Foundation. RAL thanks Ramon L. Jordan (USDA-ARS, MPPL), Rayapati A. Naidu(Washington State University), and Scott Adkins (USDA ARS USHRL) for their logistic support in the realization of the originating symposium.Peer reviewe
- …