616 research outputs found
Electromechanical wavelength tuning of double-membrane photonic crystal cavities
We present a method for tuning the resonant wavelength of photonic crystal
cavities (PCCs) around 1.55 um. Large tuning of the PCC mode is enabled by
electromechanically controlling the separation between two parallel InGaAsP
membranes. A fabrication method to avoid sticking between the membranes is
discussed. Reversible red/blue shifting of the symmetric/anti-symmetric modes
has been observed, which provides clear evidence of the electromechanical
tuning, and a maximum shift of 10 nm with < 6 V applied bias has been obtained.Comment: 9 pages, 3 figure
Bayesian Non-Exhaustive Classification A Case Study: Online Name Disambiguation using Temporal Record Streams
The name entity disambiguation task aims to partition the records of multiple
real-life persons so that each partition contains records pertaining to a
unique person. Most of the existing solutions for this task operate in a batch
mode, where all records to be disambiguated are initially available to the
algorithm. However, more realistic settings require that the name
disambiguation task be performed in an online fashion, in addition to, being
able to identify records of new ambiguous entities having no preexisting
records. In this work, we propose a Bayesian non-exhaustive classification
framework for solving online name disambiguation task. Our proposed method uses
a Dirichlet process prior with a Normal * Normal * Inverse Wishart data model
which enables identification of new ambiguous entities who have no records in
the training data. For online classification, we use one sweep Gibbs sampler
which is very efficient and effective. As a case study we consider
bibliographic data in a temporal stream format and disambiguate authors by
partitioning their papers into homogeneous groups. Our experimental results
demonstrate that the proposed method is better than existing methods for
performing online name disambiguation task.Comment: to appear in CIKM 201
Challenges in the Search for Perchlorate and Other Hydrated Minerals With 2.1-μm Absorptions on Mars
A previously unidentified artifact has been found in Compact Reconnaissance Imaging Spectrometer for Mars targeted I/F data. It exists in a small fraction (<0.05%) of pixels within 90% of images investigated and occurs in regions of high spectral/spatial variance. This artifact mimics real mineral absorptions in width and depth and occurs most often at 1.9 and 2.1 μm, thus interfering in the search for some mineral phases, including alunite, kieserite, serpentine, and perchlorate. A filtering step in the data processing pipeline, between radiance and I/F versions of the data, convolves narrow artifacts (“spikes”) with real atmospheric absorptions in these wavelength regions to create spurious absorption-like features. The majority of previous orbital detections of alunite, kieserite, and serpentine we investigated can be confirmed using radiance and raw data, but few to none of the perchlorate detections reported in published literature remain robust over the 1.0- to 2.65-μm wavelength range
Moderators of the effect of psychological interventions on depression and anxiety in cardiac surgery patients: A systematic review and meta-analysis
Cardiac surgery patients may be provided with psychological interventions to counteract depression and anxiety associated with surgical procedures. This systematic review and meta-analysis investigated whether intervention efficacy was impacted by type of cardiac procedure/cardiac event; control condition content; intervention duration; intervention timing; facilitator type; and risk of bias. MEDLINE, EMBASE, and PsycINFO were searched for randomized controlled trials comparing anxiety and depression outcomes, pre and post psychological and cardiac interventions. Twenty-four studies met the inclusion criteria for the systematic review (N = 2718) and 16 of those were meta-analysed (N = 1928). Depression and anxiety outcomes were reduced more in interventions that lasted longer, were delivered post-surgery, and by trained health professionals. Depression (but not anxiety) was reduced more when the experimental intervention was compared to an ‘alternative’ intervention, and when the intervention was delivered to coronary artery bypass graft patients. Anxiety (but not depression) was decreased more when interventions were delivered to implantable cardioverter defibrillator patients, and were of ‘high’ or ‘unclear’ risk of bias. In addition to estimating efficacy, future work in this domain needs to take into account the moderating effects of intervention, sample, and study characteristics
The interaction between ectomycorrhizal fungi and growth promoting bacteria in plant development from in-vitro to the field
There is currently an array of biotechnological tools which may positively influence plant development and establishment. Symbiosis with ectomycorrhizal fungi is known to improve plant health by increasing nutrient and water uptake and alleviating environmental stresses. Some rhizosphere bacteria are also proven to act as plant stimulating agents, health managers and growth promoters. The use of a combined inoculum using both microorganisms has great potential in forestry. Nevertheless, the interaction between fungi and bacteria is highly specific and bacteria are known not only to enhance fungal growth (mycorrhiza promoting bacteria), but also to strongly inhibit it. It is therefore important to evaluate the compatibility between ectomycorrhizal fungi and bacteria and to determine the impact of such combination in plant development when aiming at the use of optimized microbial inoculum for enhancing plant growth. In the present work we investigated the use of a dual inoculation system, consisting of a bacterial strain from the genus Mesorhizobium in combination with ectomycorrhizal fungi, from in-vitro tests to a nursery stage followed by transplantation to the field. Approximately 5000 seedlings were used in these experiments comprising Quercus suber, Quercus robur, Quercus rubra, Pinus pinaster and Pinus pinea. Seedlings were grown for 9 months in a commercial forest greenhouse and then transplanted to 4 locations in Portugal. The first sampling was made before field transplantation. Results showed that the combined use of fungi-bacteria inoculum significantly influenced plant growth and its effect was different from that of each individual microbial partner, emphasizing the strong interaction between microorganisms
Combining ectomycorrhizal fungi and bacteria: a powerful tool to improve tree performance
Ectomycorrhizal fungi are ubiquitous to forest soils and the symbiosis between these microorganisms and plants roots is known to be essential for tree establishment and development, especially in areas of poor soil. Studies have also shown that some rhizosphere bacteria may act as plant stimulating agents and growth promoters. Additionally, bacteria and fungi strongly interact and therefore the analysis of the triangle plant-fungi-bacteria is a vital approach when aiming at the use of microbial inocula to enhance plant performance. To obtain a synergistic combination between microorganisms, a thorough selection is required since bacteria may strongly inhibit fungal growth, and vice versa, incurring in the risk of failed inoculum. In the present work we investigated the use of a dual inoculation system, consisting of a bacterial strain from the genus Mesorhizobium in combination with selected ectomycorrhizal fungi. In vitro tests were performed to assess the dynamic of co-culturing both microorganisms. The inoculum was applied at nursery stage and saplings were then transplanted into the field. Approximately 5000 seedlings were used in this experiment comprising the following species: Quercus suber, Quercus robur, Quercus rubra, Pinus pinaster and Pinus pinea. Seedlings were grown for 9 months in a commercial forest greenhouse and then transplanted to 4 locations in Portugal: Mindelo, Santo Tirso, Vila do Conde and Proença-a-Nova. Samples were taken at the end of nursery phase and 8 months after transplantation. Biometric and mycorrhizal parameters were analyzed and the persistence of the inoculated strains was evaluated. The presence of selected phytohormones was also determined. Results showed that the combined use of fungi-bacteria inoculum can be more effective than the use of each individual microbial partner. The use of ectomycorrhizal fungi and bacteria has great potential in forestry as a biotechnological tool to produce high performance plants at nursery stage and in the field
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