106 research outputs found

    A Natural Experiment on Innovation Without Patents

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    Innovation occurs within a complex web of law. Of the myriad legal doctrines that affect innovation, the most directly relevant is intellectual property, particularly patent law. The United States Constitution, in Article I, Section 8, states a strong public policy goal for the granting of patents (and copyrights) to inventors: “To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.” Despite the Founding Fathers’ apparent faith in the societal benefits afforded by patent protection, a crescendo of recent critics have accused the patent system of complicating, slowing, or even thwarting innovation. Patents certainly present significant hurdles for open and user innovation. Moreover, von Hippel (2005) and Strandburg (2008) have demonstrated that user innovators, especially individuals, tend to be poorly served, and often harmed, by the patent system

    Cloning and characterization of Daphnia mitochondrial DNA

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    The mitochondrial genome of Daphnia pulex (Crustacea, Cladocera) was cloned as a single fragment into the plasmid vector pUC12. The genome size, estimated from restriction endonuclease fragment lengths, is 15,400Âą200 base pairs. The GC content, estimated from thermal denaturation studies, is 42%. The positions of 39 cleavage sites were mapped for 14 restriction enzymes. The distribution of these sites within the genome is random ( P =0.44). Heterologous hybridizations with Drosophila sylvestris mitochondrial DNA (mtDNA) probes indicate that gene orders within Daphnia and Drosophila mtDNAs are similar.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48044/1/239_2005_Article_BF02193629.pd

    Incomplete homogenization of 18 S ribosomal DNA coding regions in Arabidopsis thaliana

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    <p>Abstract</p> <p>Background</p> <p>As a result of concerted evolution, coding regions of ribosomal DNA sequences are highly conserved within species and variation is generally thought to be limited to a few nucleotides. However, rDNA sequence variation has not been systematically examined in plant genomes, including that of the model plant <it>Arabidopsis thaliana </it>whose genome was the first to be sequenced.</p> <p>Findings</p> <p>Both genomic and transcribed 18 S sequences were sampled and revealed that most deviation from the consensus sequence was limited to single nucleotide substitutions except for a variant with a 270 bp deletion from position 456 to 725 in <it>Arabidopsis </it>numbering. The deletion maps to the functionally important and highly conserved 530 loop or helix18 in the structure of <it>E. coli </it>16 S. The expression of the deletion variant is tightly controlled during developmental growth stages. Transcripts were not detectable in young seedlings but could be amplified from RNA extracts of mature leaves, stems, flowers and roots of <it>Arabidopsis thaliana </it>ecotype Columbia. We also show polymorphism for the deletion variant among four <it>Arabidopsis </it>ecotypes examined.</p> <p>Conclusion</p> <p>Despite a strong purifying selection that might be expected against functionally impaired rDNAs, the newly identified variant is maintained in the <it>Arabidopsis </it>genome. The expression of the variant and the polymorphism displayed by <it>Arabidopsis </it>ecotypes suggest a transition state in concerted evolution.</p

    Adaptive model-driven user interface development systems

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    Adaptive user interfaces (UIs) were introduced to address some of the usability problems that plague many software applications. Model-driven engineering formed the basis for most of the systems targeting the development of such UIs. An overview of these systems is presented and a set of criteria is established to evaluate the strengths and shortcomings of the state-of-the-art, which is categorized under architectures, techniques, and tools. A summary of the evaluation is presented in tables that visually illustrate the fulfillment of each criterion by each system. The evaluation identified several gaps in the existing art and highlighted the areas of promising improvement

    Cryptic species in a well-known habitat: applying taxonomics to the amphipod genus Epimeria (Crustacea, Peracarida)

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    Taxonomy plays a central role in biological sciences. It provides a communication system for scientists as it aims to enable correct identification of the studied organisms. As a consequence, species descriptions should seek to include as much available information as possible at species level to follow an integrative concept of ‘taxonomics’. Here, we describe the cryptic species Epimeria frankei sp. nov. from the North Sea, and also redescribe its sister species, Epimeria cornigera. The morphological information obtained is substantiated by DNA barcodes and complete nuclear 18S rRNA gene sequences. In addition, we provide, for the first time, full mitochondrial genome data as part of a metazoan species description for a holotype, as well as the neotype. This study represents the first successful implementation of the recently proposed concept of taxonomics, using data from highthroughput technologies for integrative taxonomic studies, allowing the highest level of confidence for both biodiversity and ecological research

    Characteristics of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) rRNA genes of Apis mellifera (Insecta: Hymenoptera): structure, organization, and retrotransposable elements

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    As an accompanying manuscript to the release of the honey bee genome, we report the entire sequence of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) ribosomal RNA (rRNA)-encoding gene sequences (rDNA) and related internally and externally transcribed spacer regions of Apis mellifera (Insecta: Hymenoptera: Apocrita). Additionally, we predict secondary structures for the mature rRNA molecules based on comparative sequence analyses with other arthropod taxa and reference to recently published crystal structures of the ribosome. In general, the structures of honey bee rRNAs are in agreement with previously predicted rRNA models from other arthropods in core regions of the rRNA, with little additional expansion in non-conserved regions. Our multiple sequence alignments are made available on several public databases and provide a preliminary establishment of a global structural model of all rRNAs from the insects. Additionally, we provide conserved stretches of sequences flanking the rDNA cistrons that comprise the externally transcribed spacer regions (ETS) and part of the intergenic spacer region (IGS), including several repetitive motifs. Finally, we report the occurrence of retrotransposition in the nuclear large subunit rDNA, as R2 elements are present in the usual insertion points found in other arthropods. Interestingly, functional R1 elements usually present in the genomes of insects were not detected in the honey bee rRNA genes. The reverse transcriptase products of the R2 elements are deduced from their putative open reading frames and structurally aligned with those from another hymenopteran insect, the jewel wasp Nasonia (Pteromalidae). Stretches of conserved amino acids shared between Apis and Nasonia are illustrated and serve as potential sites for primer design, as target amplicons within these R2 elements may serve as novel phylogenetic markers for Hymenoptera. Given the impending completion of the sequencing of the Nasonia genome, we expect our report eventually to shed light on the evolution of the hymenopteran genome within higher insects, particularly regarding the relative maintenance of conserved rDNA genes, related variable spacer regions and retrotransposable elements

    Distinctive mitochondrial genome of Calanoid copepod Calanus sinicus with multiple large non-coding regions and reshuffled gene order: Useful molecular markers for phylogenetic and population studies

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    <p>Abstract</p> <p>Background</p> <p>Copepods are highly diverse and abundant, resulting in extensive ecological radiation in marine ecosystems. <it>Calanus sinicus </it>dominates continental shelf waters in the northwest Pacific Ocean and plays an important role in the local ecosystem by linking primary production to higher trophic levels. A lack of effective molecular markers has hindered phylogenetic and population genetic studies concerning copepods. As they are genome-level informative, mitochondrial DNA sequences can be used as markers for population genetic studies and phylogenetic studies.</p> <p>Results</p> <p>The mitochondrial genome of <it>C. sinicus </it>is distinct from other arthropods owing to the concurrence of multiple non-coding regions and a reshuffled gene arrangement. Further particularities in the mitogenome of <it>C. sinicus </it>include low A + T-content, symmetrical nucleotide composition between strands, abbreviated stop codons for several PCGs and extended lengths of the genes <it>atp6 </it>and <it>atp8 </it>relative to other copepods. The monophyletic Copepoda should be placed within the Vericrustacea. The close affinity between Cyclopoida and Poecilostomatoida suggests reassigning the latter as subordinate to the former. Monophyly of Maxillopoda is rejected. Within the alignment of 11 <it>C. sinicus </it>mitogenomes, there are 397 variable sites harbouring three 'hotspot' variable sites and three microsatellite loci.</p> <p>Conclusion</p> <p>The occurrence of the <it>circular subgenomic fragment </it>during laboratory assays suggests that special caution should be taken when sequencing mitogenomes using long PCR. Such a phenomenon may provide additional evidence of mitochondrial DNA recombination, which appears to have been a prerequisite for shaping the present mitochondrial profile of <it>C. sinicus </it>during its evolution. The lack of synapomorphic gene arrangements among copepods has cast doubt on the utility of gene order as a useful molecular marker for deep phylogenetic analysis. However, mitochondrial genomic sequences have been valuable markers for resolving phylogenetic issues concerning copepods. The variable site maps of <it>C. sinicus </it>mitogenomes provide a solid foundation for population genetic studies.</p
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