QKRK FACTORIZATION FOR IMAGE COMPRESSION

We store and exchange more digital images than ever before. Image qualities are often reduced to decrease the cost of storage and transfer of the images. Digital image compression is a technique that reduces the size of an image while preserving its quality to be acceptable for a particular purpose. Matrix factorizations are widely used for this purpose. This paper presents an application of the QKRK and block QKRK factorizations of a matrix to image compression. We have conducted a series of experiments using Matlab software. This paper presents the comparative analysis of the compressed images using the QR, SV D, QKRK, and block QKRK factorizations. The similarity between the original and compressed images is measured using the L2-norm and structural similarity. It is demonstrated that using the QKRK factorization for image compression allows the achievement of the desired quality of a fragment of the image compared to the rest of the image and is also computationally efficient

TENENCIA DE LA TIERRA, USO Y CONSERVACIÓN DE LOS RECURSOS NATURALES EN EL PARQUE NACIONAL NEVADO DE TOLUCA,

La investigación que se propone identificará las diversas formas de acceso a la tierra, tanto ejidal, comunal y privada por medio de las cuales los habitantes de un centro de población ubicada en el Parque Nacional Nevado de Toluca tienen acceso a los recursos del área. Además, se determinará cómo esas formas de tenencia influyen sobre el acceso individual, familiar o grupal, y cómo definen las formas de aprovechamiento de los distintos recursos: agua, suelo y bosque. Al mismo tiempo se identificarán las normas locales que rigen estos aspectos y su relación con las normas formales y las políticas estatales y federales de protección ambiental

The First α Helix of Interleukin (Il)-2 Folds as a Homotetramer, Acts as an Agonist of the IL-2 Receptor β Chain, and Induces Lymphokine-Activated Killer Cells

Interleukin (IL)-2 interacts with two types of functional receptors (IL-2Rαβγ and IL-2Rβγ) and acts on a broad range of target cells involved in inflammatory reactions and immune responses. For the first time, we show that a chemically synthesized fragment of the IL-2 sequence can fold into a molecule mimicking the quaternary structure of a hemopoietin. Indeed, peptide p1–30 (containing amino acids 1–30, covering the entire α helix A of IL-2) spontaneously folds into an α-helical homotetramer and stimulates the growth of T cell lines expressing human IL-2Rβ, whereas shorter versions of the peptide lack helical structure and are inactive. We also demonstrate that this neocytokine interacts with a previously undescribed dimeric form of IL-2Rβ. In agreement with its binding to IL-2Rβ, p1–30 activates Shc and p56lck but unlike IL-2, fails to activate Janus kinase (Jak)1, Jak3, and signal transducer and activator of transcription 5 (STAT5). Unexpectedly, we also show that p1–30 activates Tyk2, thus suggesting that IL-2Rβ may bind to different Jaks depending on its oligomerization. At the cellular level, p1–30 induces lymphokine-activated killer (LAK) cells and preferentially activates CD8low lymphocytes and natural killer cells, which constitutively express IL-2Rβ. A significant interferon γ production is also detected after p1–30 stimulation. A mutant form of p1–30 (Asp20→Lys), which is likely unable to induce vascular leak syndrome, remains capable of generating LAK cells, like the original p1–30 peptide. Altogether, our data suggest that p1–30 has therapeutic potential

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead