Solar Advisor Model User Guide for Version 2.0 (open access)

Solar Advisor Model User Guide for Version 2.0

The Solar Advisor Model (SAM) provides a consistent framework for analyzing and comparing power system costs and performance across the range of solar technologies and markets, from photovoltaic systems for residential and commercial markets to concentrating solar power and large photovoltaic systems for utility markets. This manual describes Version 2.0 of the software, which can model photovoltaic and concentrating solar power technologies for electric applications for several markets. The current version of the Solar Advisor Model does not model solar heating and lighting technologies.
Date: August 1, 2008
Creator: Gilman, P.; Blair, N.; Mehos, M.; Christensen, C.; Janzou, S. & Cameron, C.
Object Type: Report
System: The UNT Digital Library
State-of-the-Art Beta Detection and Dosimetry (open access)

State-of-the-Art Beta Detection and Dosimetry

The research funded by this NEER grant establishes the framework for a detailed understanding of the challenges in beta dosimetry, especially in the presence of a mixed radiation field. The work also stimulated the thinking of the research group which will lead to new concepts in digital signal processing to allow collection of detection signals and real-time analysis such that simultaneous beta and gamma spectroscopy can take place. The work described herein (with detail in the many publications that came out of this research) was conducted in a manner that provided dissertation and thesis topics for three students, one of whom was completely funded by this grant. The overall benefit of the work came in the form of a dramatic shift in signal processing that is normally conducted in analog pulse shape analysis. Analog signal processing was shown not to be feasible for this type of work; digital signal processing was a must. This, in turn, led the research team to a new understanding of pulse analysis, one in which expands the state-of-the-art in simultaneous beta and gamma spectroscopy with a single detector.
Date: August 15, 2008
Creator: Hamby, David M.
Object Type: Report
System: The UNT Digital Library
Approaching 10% Conversion Efficiency Using Tandem Organic Photovoltaic Cells with Enhanced Optical Coupling: Final Report, October 2004 - December 2007 (open access)

Approaching 10% Conversion Efficiency Using Tandem Organic Photovoltaic Cells with Enhanced Optical Coupling: Final Report, October 2004 - December 2007

To find routes to achieving nearly 10% power conversion efficiency based on a new generation of organic photovoltaic cells using vapor-deposited, small-molecular-weight organic materials.
Date: August 1, 2008
Creator: Forrest, S.
Object Type: Report
System: The UNT Digital Library
Save Energy Now Reveals New Opportunities for Steel Manufacturers to Reduce Costs and Energy Use (open access)

Save Energy Now Reveals New Opportunities for Steel Manufacturers to Reduce Costs and Energy Use

This case study describes how the Industrial Technologies Program helps steel companies find ways to improve the efficiency of energy-intensive process heating and steam systems by performing Save Energy Now energy assessments.
Date: August 1, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Washington International Renewable Energy Conference 2008 Pledges: Methodology and Assumptions Summary (open access)

Washington International Renewable Energy Conference 2008 Pledges: Methodology and Assumptions Summary

The 2008 Washington International Renewable Energy Conference (WIREC) was held in Washington, D.C., from March 4-6, 2008, and involved nearly 9,000 people from 125 countries. The event brought together worldwide leaders in renewable energy (RE) from governments, international organizations, nongovernmental organizations, and the private sector to discuss the role that renewables can play in alleviating poverty, growing economies, and passing on a healthy planet to future generations. The conference concluded with more than 140 governments, international organizations, and private-sector representatives pledging to advance the uptake of renewable energy. The U.S. government authorized the National Renewable Energy Laboratory (NREL) to estimate the carbon dioxide (CO2) savings that would result from the pledges made at the 2008 conference. This report describes the methodology and assumptions used by NREL in quantifying the potential CO2 reductions derived from those pledges.
Date: August 1, 2008
Creator: Babiuch, B.; Bilello, D. E.; Cowlin, S. C.; Mann, M. & Wise, A.
Object Type: Report
System: The UNT Digital Library
Development of Next Generation Multiphase Pipe Flow Prediction Tools (open access)

Development of Next Generation Multiphase Pipe Flow Prediction Tools

The developments of fields in deep waters (5000 ft and more) is a common occurrence. It is inevitable that production systems will operate under multiphase flow conditions (simultaneous flow of gas-oil-and water possibly along with sand, hydrates, and waxes). Multiphase flow prediction tools are essential for every phase of the hydrocarbon recovery from design to operation. The recovery from deep-waters poses special challenges and requires accurate multiphase flow predictive tools for several applications including the design and diagnostics of the production systems, separation of phases in horizontal wells, and multiphase separation (topside, seabed or bottom-hole). It is very crucial to any multiphase separation technique that is employed either at topside, seabed or bottom-hole to know inlet conditions such as the flow rates, flow patterns, and volume fractions of gas, oil and water coming into the separation devices. The overall objective was to develop a unified model for gas-oil-water three-phase flow in wells, flow lines, and pipelines to predict the flow characteristics such as flow patterns, phase distributions, and pressure gradient encountered during petroleum production at different flow conditions (pipe diameter and inclination, fluid properties and flow rates). The project was conducted in two periods. In Period 1 (four years), gas-oil-water …
Date: August 31, 2008
Creator: Flow, Tulsa Fluid
Object Type: Report
System: The UNT Digital Library
Investigation of the amorphous to crystalline phase transition of chemical solution deposited Pb(Zr30Ti70)O3 thin films by soft x-ray absorption and soft x-ray emission spectroscopy (open access)

Investigation of the amorphous to crystalline phase transition of chemical solution deposited Pb(Zr30Ti70)O3 thin films by soft x-ray absorption and soft x-ray emission spectroscopy

Chemical solution deposited (CSD) complex oxide thin films attract considerable interest in various emerging fields as for example, fuel cells, ferroelectric random access memories or coated conductors. In the present paper the results of soft-x-ray spectroscopy between 100 eV and 500 eV on the amorphous to crystalline phase transition of ferroelectric PbZr{sub 0.3}Ti{sub 0.7}O{sub 3} (PZT) thin films are presented. Five CSD samples derived from the same wafer coated with a PZT film pyrolyzed at 350 C were heat treated at different temperatures between 400 C and 700 C. At first the sample were morphologically and electrically characterized. Subsequently the soft-x-ray absorption and emission experiments were performed at the undulator beamline 8.0 of the Advanced Light Source of the Lawrence Berkeley National Laboratory. Soft-x-ray absorption spectra were acquired for the Ti L{sub 2,3-}, O K-, and C K-edge thresholds by using simultaneously the total electron yield (TEY) and total fluorescence yield (TFY) detection methods. For two samples, annealed at 400 C and 700 C, respectively, the resonant inelastic soft-x-ray spectroscopy (RIXS) was applied for various excitation energies near the Ti L-, O K-edges. We observed clear evidence of a rutile phase at untypically low temperatures. This rutile phase transforms into …
Date: August 1, 2008
Creator: Schneller, T.; Schneller, T.; Kohlstedt, H.; Petraru, A.; Waser, R.; Guo, J. et al.
Object Type: Article
System: The UNT Digital Library
Hyperon Polarization in Unpolarized Scattering Processes (open access)

Hyperon Polarization in Unpolarized Scattering Processes

Transverse polarization in the Hyperon (\Lambda) production in the unpolarizeddeep inelastic scattering and pp collisions is studied in the twist-three approach, considering the contribution from the quark-gluon-antiquark correlation distribution in nucleon. We further compare our results for deep inelastic scattering to a transverse momentum dependent factorization approach, and find consistency between the two approaches in the intermediate transverse momentum region. We also find that in pp collisions, there are only derivative terms contributions, and the non-derivative terms vanish.
Date: August 27, 2008
Creator: Zhou, Jian; Yuan, Feng & Liang, Zuo-Tang
Object Type: Article
System: The UNT Digital Library
CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS (open access)

CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS

Recent reports have shown that, despite efforts to the contrary, chemical accidents continue to occur at an unacceptable rate and there is no evidence that this rate is decreasing. Based on this observation, one can conclude that previous analyses have not accurately identified and implemented appropriate fixes to eliminate identified root causes for chemical events. Based on this, it is time to reevaluate chemical accident data with a fresh eye and determine (a) what corrective actions have already been identified but have not been implemented, (b) what other root causes may be involved, and (c) what new corrective actions should be taken to eliminate these newly identified root causes.
Date: August 5, 2008
Creator: Simmons, F
Object Type: Article
System: The UNT Digital Library
Mixing and CP Violation at the Tevatron (open access)

Mixing and CP Violation at the Tevatron

Measurements of meson mixing and CP violation parameters obtained by the CDF and D0 experiments at the Fermilab Tevatron are presented. These include results on B{sub s} and D meson mixing, and searches for CP violation in the decay B{sup +} {yields} J/{psi}K{sup +}, in mixing through semileptonic B{sub s} meson decays, and in the interference between mixing and decay in the process B{sub s} {yields} J/{psi}{phi}.
Date: August 1, 2008
Creator: Brooijmans, G.
Object Type: Article
System: The UNT Digital Library
Zachary D. Barker: Final DHS HS-STEM Report (open access)

Zachary D. Barker: Final DHS HS-STEM Report

Working at Lawrence Livermore National Laboratory (LLNL) this summer has provided a very unique and special experience for me. I feel that the research opportunities given to me have allowed me to significantly benefit my research group, the laboratory, the Department of Homeland Security, and the Department of Energy. The researchers in the Single Particle Aerosol Mass Spectrometry (SPAMS) group were very welcoming and clearly wanted me to get the most out of my time in Livermore. I feel that my research partner, Veena Venkatachalam of MIT, and I have been extremely productive in meeting our research goals throughout this summer, and have learned much about working in research at a national laboratory such as Lawrence Livermore. I have learned much about the technical aspects of research while working at LLNL, however I have also gained important experience and insight into how research groups at national laboratories function. I believe that this internship has given me valuable knowledge and experience which will certainly help my transition to graduate study and a career in engineering. My work with Veena Venkatachalam in the SPAMS group this summer has focused on two major projects. Initially, we were tasked with an analysis of data …
Date: August 14, 2008
Creator: Barker, Z D
Object Type: Report
System: The UNT Digital Library
Measurement of Branching Fractions of Radiative Charm Decays (open access)

Measurement of Branching Fractions of Radiative Charm Decays

We present a measurement of the branching fractions for the Cabibbo-favored radiative decay, D{sup 0} {yields} {bar K}*{sup 0}{gamma}, and the Cabibbo-suppressed radiative decay, D{sup 0} {yields} {phi}{gamma}. These measurements are based on a data sample corresponding to an integrated luminosity of 387.1 fb{sup -1}, recorded with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric-energy collider operating at center-of-mass energies 10.58 and 10.54 GeV. We measure the branching fractions relative to the well-studied decay D{sup 0} {yields} K{sup -}{pi}{sup +} and find {Beta}(D{sup 0} {yields} {bar K}*{sup 0}{gamma})/{Beta}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = (8.43 {+-} 0.51 {+-} 0.70) x 10{sup -3} and {Beta}(D{sup 0} {yields} {phi}{gamma})/{Beta}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = (7.15 {+-} 0.78 {+-} 0.69) x 10{sup -4}, where the first error is statistical and the second is systematic. This is the first measurement of {Beta}(D{sup 0} {yields} {bar K}*{sup 0} {gamma}).
Date: August 18, 2008
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering (open access)

Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering

The XRMS experiment on the Gd{sub 5}Ge{sub 4} system has shown that, below the Neel temperature, T{sub N} = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic slabs are stacked antiferromagnetically along the b-direction. They found an unusual order parameter curve in Gd{sub 5}Ge{sub 4}. A spin-reorientation transition is a possibility in Gd{sub 5}Ge{sub 4}, which is similar to the Tb{sub 5}Ge{sub 4} case. Tb{sub 5}Ge{sub 4} possesses the same Sm{sub 5}Ge{sub 4}-type crystallographic structure and the same magnetic space group as Gd{sub 5}Ge{sub 4} does. The difference in magnetic structure is that Tb{sub 5}Ge{sub 4} has a canted one but Gd{sub 5}Ge{sub 4} has nearly a collinear one in the low temperature antiferromagnetic phase. The competition between the magneto-crystalline anisotropy and the nearest-neighbor magnetic exchange interactions may allow a 3-dimensional canted antiferromagnetic structure in Tb{sub 5}Ge{sub 4}. The spin-reorientation transition …
Date: August 18, 2008
Creator: Tan, Lizhi
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Commissioning of the LCLS Linac and Bunch Compressors (open access)

Commissioning of the LCLS Linac and Bunch Compressors

The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) project under construction at SLAC [1]. The injector section, from drive-laser and RF photocathode gun through the first bunch compressor, was commissioned in the spring and summer of 2007. The second phase of commissioning, including the second bunch compressor and various main linac modifications, was completed in January through August of 2008. We report here on experience gained during this second phase of machine commissioning, including the injector, the first and second bunch compressor stages, the linac up to 14 GeV, and beam stability measurements. The final commissioning phase, including the undulator and the long transport line from the linac, is set to begin in December 2008, with first light expected in July 2009.
Date: August 20, 2008
Creator: Akre, R.; Brachmann, A.; Decker, F.-J.; Ding, Y.; Dowell, D.; Emma#, P. et al.
Object Type: Article
System: The UNT Digital Library
Facility Closure Report for T-Tunnel (U12t), Area 12, Nevada Test Site, Nevada (open access)

Facility Closure Report for T-Tunnel (U12t), Area 12, Nevada Test Site, Nevada

This Facility Closure Report (FCR) has been prepared to document the actions taken to permanently close the remaining accessible areas of U12t-Tunnel (T-Tunnel) in Area 12 of the Nevada Test Site (NTS). The closure of T-Tunnel was a prerequisite to transfer facility ownership from the Defense Threat Reduction Agency (DTRA) to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Closure of the facility was accomplished with the cooperation and concurrence of both NNSA/NSO and the Nevada Division of Environmental Protection (NDEP). The purpose of this FCR is to document that the closure of T-Tunnel complied with the closure requirements specified in the Facility Closure Plan for N- and T-Tunnels Area 12, Nevada Test Site (Appendix D) and that the facility is ready for transfer to NNSA/NSO. The Facility Closure Plan (FCP) is provided in Appendix D. T-Tunnel is located approximately 42 miles north of Mercury in Area 12 of the NTS (Figure 1). Between 1970 and 1987, T-Tunnel was used for six Nuclear Weapons Effects Tests (NWETs). The tunnel was excavated horizontally into the volcanic tuffs of Rainier Mesa. The T-Tunnel complex consists of a main access drift with two NWET containment structures, a Gas …
Date: August 1, 2008
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
On a Thermal Analysis of a Second Stripper for Rare Isotope Accelerator. (open access)

On a Thermal Analysis of a Second Stripper for Rare Isotope Accelerator.

This memo summarizes simple calculations and results of the thermal analysis on the second stripper to be used in the driver linac of Rare Isotope Accelerator (RIA). Both liquid (Sodium) and solid (Titanium and Vanadium) stripper concepts were considered. These calculations were intended to provide basic information to evaluate the feasibility of liquid (thick film) and solid (rotating wheel) second strippers. Nuclear physics calculations to estimate the volumetric heat generation in the stripper material were performed by 'LISE for Excel'. In the thermal calculations, the strippers were modeled as a thin 2D plate with uniform heat generation within the beam spot. Then, temperature distributions were computed by assuming that the heat spreads conductively in the plate in radial direction without radiative heat losses to surroundings.
Date: August 4, 2008
Creator: Momozaki, Y. & Nolen, J.
Object Type: Report
System: The UNT Digital Library
Long-term corrosion testing pan. (open access)

Long-term corrosion testing pan.

This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing needs. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to meet all future testing …
Date: August 1, 2008
Creator: Wall, Frederick Douglas & Brown, Neil R. (Los Alamos National Laboratory, Los Alamos, NM)
Object Type: Report
System: The UNT Digital Library
Measurement of the Top Quark Mass using Quantities with Minimal Dependence on the Jet Energy Scale (open access)

Measurement of the Top Quark Mass using Quantities with Minimal Dependence on the Jet Energy Scale

None
Date: August 1, 2008
Creator: Garberson, F.; Incandela, J.; Koay, S.; Rossin, R.; /UC, Santa Barbara; Hill, C. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of D^0-\bar{D^0} Mixing From a Time-Dependent Amplitude Analysis of D^0\ -> K^+\pi^-\pi0 Decays (open access)

Measurement of D^0-\bar{D^0} Mixing From a Time-Dependent Amplitude Analysis of D^0\ -> K^+\pi^-\pi0 Decays

The authors present evidence of D{sup 0}-{bar D}{sup 0} mixing using a time-dependent amplitude analysis of the decay D{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} in a data sample of 384 fb{sup -1} collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. Assuming CP conservation, they measure the mixing parameters x{prime}{sub K{pi}{pi}{sup 0}} = [2.61{sub -0.68}{sup +0.57}(stat.) {+-} 0.39(syst.)]%, y{prime}{sub K{pi}{pi}{sup 0}} = [-0.06{sub -0.64}{sup +0.55}(stat.) {+-} 0.34(syst.)]%. The confidence level for the data to be consistent with the no-mixing hypothesis is 0.1%, including systematic uncertainties. This result is inconsistent with the no-mixing hypothesis with a significance of 3.2 standard deviations. They find no evidence of CP violation in mixing.
Date: August 4, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Object Type: Article
System: The UNT Digital Library
Advanced, High-Reliability, System-Integrated 500kW PV Inverter Development: Final Subcontract Report, 29 September 2005 - 31 May 2008 (open access)

Advanced, High-Reliability, System-Integrated 500kW PV Inverter Development: Final Subcontract Report, 29 September 2005 - 31 May 2008

Xantrex Technology accomplished subcontract goals of reducing parts cost, weight, and size of its 500-kW inverter by 25% compared to state-of-the-art PV inverters, while extending reliability by 25%.
Date: August 1, 2008
Creator: West, R.
Object Type: Report
System: The UNT Digital Library

Discovering and validating biological hypotheses from coherent patterns in functional genomics data

The area of transcriptomics analysis is among the more established in computational biology, having evolved in both technology and experimental design. Transcriptomics has a strong impetus to develop sophisticated computational methods due to the large amounts of available whole-genome datasets for many species and because of powerful applications in regulatory network reconstruction as well as elucidation and modeling of cellular transcriptional responses. While gene expression microarray data can be noisy and comparisons across experiments challenging, there are a number of sophisticated methods that aid in arriving at statistically and biologically significant conclusions. As such, computational transcriptomics analysis can provide guidance for analysis of results from newer experimental technologies. More recently, search methods have been developed to identify modules of genes, which exhibit coherent expression patterns in only a subset of experimental conditions. The latest advances in these methods allow to integrate multiple data types anddatasets, both experimental and computational, within a single statistical framework accounting for data confidence and relevance to specific biological questions. Such frameworks provide a unified environment for the exploration of specific biological hypothesis and for the discovery of coherent data patterns along with the evidence supporting them.
Date: August 12, 2008
Creator: Joachimiak, Marcin Pawel
Object Type: Presentation
System: The UNT Digital Library
Pilot Testing of WRI'S Novel Mercury Control Technology by Pre-Combustion Thermal Treatment of Coal (open access)

Pilot Testing of WRI'S Novel Mercury Control Technology by Pre-Combustion Thermal Treatment of Coal

The challenges to the coal-fired power industry continue to focus on the emission control technologies, such as mercury, and plant efficiency improvements. An alternate approach to post-combustion control of mercury, while improving plant efficiency deals with Western Research Institute's (WRI)'s patented pre-combustion mercury removal and coal upgrading technology. WRI was awarded under the DOE's Phase III Mercury program, to evaluate the effectiveness of WRI's novel thermal pretreatment process to achieve >50% mercury removal, and at costs of <$30,000/lb of Hg removed. WRI has teamed with Etaa Energy, Energy and Environmental Research Center (EERC), Foster Wheeler North America Corp. (FWNA), and Washington Division of URS (WD-URS), and with project co-sponsors including Electric Power Research Institute (EPRI), Southern Company, Basin Electric Power Cooperative (BEPC), Montana-Dakota Utilities (MDU), North Dakota Industrial Commission (NDIC), Detroit Edison (DTE), and SaskPower to undertake this evaluation. The technical objectives of the project were structured in two phases: Phase I--coal selection and characterization, and bench-and PDU-scale WRI process testing and; and Phase II--pilot-scale pc combustion testing, design of an integrated boiler commercial configuration, its impacts on the boiler performance and the economics of the technology related to market applications. This report covers the results of the Phase I …
Date: August 17, 2008
Creator: Bland, Alan; Newcomer, Jesse & Sellakumar, Kumar
Object Type: Report
System: The UNT Digital Library
Search for new physics in the Compact Muon Solenoid (CMS) experiment and the response of the CMS calorimeters to particles and jets (open access)

Search for new physics in the Compact Muon Solenoid (CMS) experiment and the response of the CMS calorimeters to particles and jets

A Monte Carlo study of a generic search for new resonances beyond the Standard Model (SM) in the CMS experiment is presented. The resonances are axigluon, coloron, E{sub 6} diquark, excited quark, W{prime}, Z{prime}, and the Randall-Sundrum graviton which decay to dijets. The dijet resonance cross section that the CMS can expect to discover at a 5{sigma} significance or to exclude at 95% confidence level for integrated luminosities of 100 pb{sup -1}, 1 fb{sup -1}, and 10 fb{sup -1} is evaluated. It is shown that a 5{sigma} discovery of a multi-TeV dijet resonance is possible for an axigluon, excited quark, and E{sub 6} diquark. However, a 5{sigma} discovery can not be projected with confidence for a W{prime}, Z{prime} and the Randall-Sundrum graviton. On the other hand, 95% CL exclusion mass regions can be measured for all resonances at high luminosities. In the second part of this dissertation, the analyses of the 2006 test beam data from the combined electromagnetic and hadronic barrel calorimeters are presented. The CMS barrel calorimeters response to a variety of beam particles in a wide momenta range (1 to 350 GeV/c) is measured. Furthermore, using these beam data, the expected performance of the barrel calorimeters to …
Date: August 1, 2008
Creator: Gumus, Kazim Ziya & Tech., /Texas
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Trichoplax Genome and the Nature of Placozoans (open access)

The Trichoplax Genome and the Nature of Placozoans

Placozoans are arguably the simplest free-living animals, possibly evoking an early stage in metazoan evolution, yet their biology is poorly understood. Here we report the sequencing and analysis of the {approx}98 million base pair nuclear genome of the placozoan Trichoplax adhaerens. Whole genome phylogenetic analysis suggests that placozoans belong to a 'eumetazoan' clade that includes cnidarians and bilaterians, with sponges as the earliest diverging animals. The compact genome exhibits conserved gene content, gene structure, and synteny relative to the human and other complex eumetazoan genomes. Despite the apparent cellular and organismal simplicity of Trichoplax, its genome encodes a rich array of transcription factor and signaling pathway genes that are typically associated with diverse cell types and developmental processes in eumetazoans, motivating further searches for cryptic cellular complexity and/or as yet unobserved life history stages.
Date: August 1, 2008
Creator: Srivastava, Mansi; Begovic, Emina; Chapman, Jarrod; Putnam, Nicholas H.; Hellsten, Uffe; Kawashima, Takeshi et al.
Object Type: Article
System: The UNT Digital Library