4,182 research outputs found
Comparison of regulatory regions in the mitochondrial genomes of grasses
Abstract only availableRegulation of transcription in plant mitochondria is not well understood. The recent sequencing of the mitochondrial genomes of 10 closely related grasses allowed a comparative analysis of regulatory regions. To look for conserved regions and potential âswappedâ regulatory regions, we have performed a comparative analysis of the upstream and downstream regions of all of the protein-coding genes in the mitochondrial genomes of eleven grasses: five mitochondrial types of maize (two fertile and three cytoplasmic male sterile), three other taxa within the genus (Zea mays ssp. parviglumis, Z. luxurians, Z. perennis), two close relatives (Tripsacum dactyloides, Sorghum bicolor), and an outgroup, rice. These genomes contain an average of 35 protein-coding genes, composed of 40 transcriptional units. Our analyses examined 1000 base pairs (bp) upstream of the first exon of each transcriptional unit and 1000 bp downstream of its last exon. The reference genome was NB, the most common fertile maize mitochondrial genotype. Compared with the genes from NB, more than half of the mitochondrial genes in the other genomes contain sequences that flank different genes in NB; we refer to these as âswappedâ regions. More than 25% of the translocated sequences are longer than 100 bp, and 21 are greater than 500 bp. The longer sequences are more likely to have a regulatory function. In addition, some of these regions were found multiple times: 12 of the translocated gene-flanking regions were found flanking five or more other genes; four had sequences that were flanking ten or more. Furthermore, in Z. luxurians, Z. perennis and T. dactyloides, the co-transcribed 18S and 5S ribosomal RNA genes have been translocated immediately upstream of the start of cox1, with the 5S rRNA 3' end only 80 bp from the start of cox1 exon 1. This is a position that is difficult to rectify with the divergent transcriptional needs of the two types of genes.Plant Genomics Internship @ M
Ecological Studies of the wolf on Isle Royale, 1970-1971
First Annual Report 1970-1971(Covering the thirteenth year in the Isle Royale Studies)https://digitalcommons.mtu.edu/wolf-annualreports/1050/thumbnail.jp
An Evaluation of Relationships Between Streamflow Patterns and Watershed Characteristics Through the Use of OPSET
Selection among alternative flood control measures would be better informed if better information could be obtained on the marginal change in flood hazard associated with land use and other changes in the tributary watershed. Hydrologic modeling is the most promising approach to answering this question; however, the use of existing models is hampered by the absence of information correlating model parameters with physical characteristics of the watershed.
To deal with this situation, a method was developed for estimating the parameter values for the Stanford Watershed Model which best match recorded with simulated streamflows. Physical characteristics were measured for 17 rural watersheds. Correlations between the characteristics and the parameters were examined. Changes in parameter values with urbanization were also examined. The results were used to study variations in downstream flood peaks and in average annual flood damages associated with various tributary watershed characteristics. The end product is better information on the kinds of areas where urban development is least likely to experience large flood damage and drainage costs
Telepsychiatric assessment of a mariner expressing suicidal ideation.
This case report highlights the successful use of telepsychiatric consultation by secure video chat to remotely assess a mariner expressing suicidal ideation. As a result of this intervention, telemedicine providers initiated psychiatric stabilisation while the mariner was still aboard the vessel, determined that he was safe for repatriation under the care of qualified medical escorts, and facilitated admission to a psychiatric facility near his home in the United States. Mental health emergencies are a significant cause of morbidity and mortality among mariners. Telepsychiatry is a validated method of establishing a psychiatric diagnosis and disposition as well as assessing risk of suicidality and the potential for violent decompensation. It has the potential to be a valuable adjunct to any traditional maritime telemedicine service
Estimation of viral richness from shotgun metagenomes using a frequency count approach
BACKGROUND: Viruses are important drivers of ecosystem functions, yet little is known about the vast majority of viruses. Viral shotgun metagenomics enables the investigation of broad ecological questions in phage communities. One ecological characteristic is species richness, which is the number of different species in a community. Viruses do not have a phylogenetic marker analogous to the bacterial 16S rRNA gene with which to estimate richness, and so contig spectra are employed to measure the number of virus taxa in a given community. A contig spectrum is generated from a viral shotgun metagenome by assembling the random sequence reads into groups of sequences that overlap (contigs) and counting the number of sequences that group within each contig. Current tools available to analyze contig spectra to estimate phage richness are limited by relying on rank-abundance data. RESULTS: We present statistical estimates of virus richness from contig spectra. The program CatchAll (http://www.northeastern.edu/catchall/) was used to analyze contig spectra in terms of frequency count data rather than rank-abundance, thus enabling formal statistical analyses. Also, the influence of potentially spurious low-frequency counts on richness estimates was minimized by two methods, empirical and statistical. The results show greater estimates of viral richness than previous calculations in nearly all environments analyzed, including swine feces and reclaimed fresh water. CONCLUSIONS: CatchAll yielded consistent estimates of richness across viral metagenomes from the same or similar environments. Additionally, analysis of pooled viral metagenomes from different environments via mixed contig spectra resulted in greater richness estimates than those of the component metagenomes. Using CatchAll to analyze contig spectra will improve estimations of richness from viral shotgun metagenomes, particularly from large datasets, by providing statistical measures of richness
The TIGRE gamma-ray telescope
TIGRE is an advanced telescope for gamma-ray astronomy with a few arcmin resolution. From 0.3 to 10 MeV it is a Compton telescope. Above 1 MeV, its multi-layers of double sided silicon strip detectors allow for Compton recoil electron tracking and the unique determination for incident photon direction. From 10 to 100 MeV the tracking feature is utilized for gamma-ray pair event reconstruction. Here we present TIGRE energy resolutions, background simulations and the development of the electronics readout system
Experiential Learning in Soil Science: Evaluating Soil Quality in South Wollo, Ethiopia
This study abroad program provided an opportunity to enhance the international experience and research skills of University of Nebraska-Lincoln (UNL) students within a multidisciplinary teamâs research-education goal on improving food security in Ethiopia. The experiential study component of the project included preparatory sessions during the Fall 2015 Semester at the UNL followed by a four- to five-week fieldwork experience in Ethiopia. Teams from the UNL and an Ethiopian university participated in survey data collection and field soil evaluations from farms in the Gerado area of South Wollo, Ethiopia. Having students interact with farmers increased student self-confidence and enhanced their leadership skills. Soil fertility evaluation provided the opportunity for students to apply soil health concepts in a practical setting, thus giving them a fuller understanding of these commonly challenging concepts. Throughout the study experience in Ethiopia, two UNL students wrote reflective journal entries each day and participated in daily wrap-ups. Students also gave permission to staff at Wollo University and to fellow students and faculty at the UNL. In addition they completed a final paper integrating the journal material and the experiential research work in Ethiopia. Students experienced cultural immersion while participating in this ongoing research project
Tracking and imaging gamma ray experiment (TIGRE) for 1 to 100 MEV gamma ray astronomy
A large international collaboration from the high energy astrophysics community has proposed the Tracking and Imaging Gamma Ray Experiment (TIGRE) for future space observations. TIGRE will image and perform energy spectroscopy measurements on celestial sources of gamma rays in the energy range from 1 to 100 MeV. This has been a difficult energy range experimentally for gamma ray astronomy but is vital for the future considering the recent exciting measurements below 1 and above 100 MeV. TIGRE is both a double scatter Compton and gamma ray pair telescope with direct imaging of individual gamma ray events.
Multiâlayers of Si strip detectors are used as Compton and pair converters CsI(Tl) scintillation detectors are used as a position sensitive calorimeter. Alternatively, thick GE strip detectors may be used for the calorimeter. The Si detectors are able to track electrons and positrons through successive Si layers and measure their directions and energy losses. Compton and pair events are completely reconstructed allowing each event to be imaged on the sky. TIGRE will provide an orderâofâmagnitude improvement in discrete source sensitivity in the 1 to 100 MeV energy range and determine spectra with excellent energy and excellent angular resolutions. Itâs wide fieldâofâview of Ï sr permits observations of the entire sky for extended periods of time over the life of the mission
- âŠ