275 research outputs found
The baryon density at z=0.9-1.9 - Tracing the warm-hot intergalactic medium with broad Lyman alpha absorption
We present an analysis of the Lyman alpha forests of five quasar spectra in
the near UV. Properties of the intergalactic medium (IGM) at an intermediate
redshift interval (0.9 < z < 1.9) are studied. The amount of baryons in the
diffuse photoionised IGM and the warm-hot intergalactic medium (WHIM) are
traced to get constraints on the redshift evolution of the different phases of
the intergalactic gas. The baryon density of the diffuse IGM is determined with
photoionisation calculations under the assumption of local hydrostatic
equilibrium. We assume that the gas is ionised by a metagalactic background
radiation with a Haardt & Madau (2001) spectrum. The WHIM is traced with broad
Lyman alpha (BLA) absorption. The properties of a number of BLA detections are
studied. Under the assumption of collisional ionisation equilibrium a lower
limit to the baryon density could be estimated. It is found that the diffuse
photoionised IGM contains at least 25% of the total baryonic matter at
redshifts 1 < z < 2. For the WHIM a lower limit of 2.4% could be determined.
Furthermore the data indicates that the intergalactic gas is in a state of
evolution at z=1.5. We confirm that a considerable part of the WHIM is created
between z=1 and z=2.Comment: 6 pages, 1 figure, accepted for publication in A&
Hybrid Software Development Approaches in Practice: A European Perspective
Agile and traditional development approaches are used in combination in todays software development. To improve the understanding and to provide better guidance for selecting appropriate development approaches, it is important to analyze such combinations in practice. Results obtained from an online survey strongly confirm that hybrid development approaches are widely used in industry. Our results show that hybrid development approaches: (i) have become reality for nearly all companies; (ii) are applied to specific projects even in the presence of company-wide policies for process usage; (iii) are neither planned nor designed but emerge from the evolution of different work practices; and, (iv) are consistently used regardless of company size or industry secto
Experimental growth law for bubbles in a "wet" 3D liquid foam
We used X-ray tomography to characterize the geometry of all bubbles in a
liquid foam of average liquid fraction and to follow their
evolution, measuring the normalized growth rate
for 7000 bubbles. While
does not depend only on the number of faces of a bubble, its average over
faced bubbles scales as for large s at all times. We
discuss the dispersion of and the influence of on
.Comment: 10 pages, submitted to PR
Computer-Assisted Proofs of Some Identities for Bessel Functions of Fractional Order
We employ computer algebra algorithms to prove a collection of identities
involving Bessel functions with half-integer orders and other special
functions. These identities appear in the famous Handbook of Mathematical
Functions, as well as in its successor, the DLMF, but their proofs were lost.
We use generating functions and symbolic summation techniques to produce new
proofs for them.Comment: Final version, some typos were corrected. 21 pages, uses svmult.cl
Concentraciones totales de Fe, Mn, Al y P en Alfisoles, Oxisoles y Ultisoles en Misiones, Argentina
Uno de los principales problemas en la producción agrícola en la Provincia de Misiones (Argentina) es la baja disponibilidad de fósforo (P) en Alfisoles, Oxisoles y Ultisoles, aunque se detectan altas concentraciones de P total. El objetivo del trabajo fue determinar la distribución de las concentraciones totales de Fe, Mn, Al y P en Alfisoles, Oxisoles y Ultisoles. Kandiudalfes Ródico y Mólico, Eutrudox Ródico, Hapludox Húmico, Kandihumultes Típicos. Se determinaron pH en agua relación 1:2,5; carbono orgánico (CO) por Walkley-Black; textura por Bouyouccos; Fósforo total (Pt) por digestión con H2 SO4 – H2 O2 – HF. El fraccionamiento de Fe, Mn, y Al se realizó siguiendo el procedimiento propuesto por Shuman y modificado por McDaniel y Buol adaptado para el fraccionamiento de elementos. Las concentraciones de Fe, Mn y Al fueron determinadas por espectrofotometría de absorción atómica. Se concluye que: i) las formas amorfas o pobremente cristalinas de Fe, fueron las formas más importantes hallada de este elemento; ii) las principales formas de Mn halladas fueron los óxidos cristalinos de Mn o formas coprecipitadas, encontrándose que las concentraciones totales de Mn disminuyeron en profundidad y están estrechamente relacionadas a los contenidos de arcillas del suelo; iii) para Al se detectaron las formas amorfas y las cristalinas de óxido de hierro o formas coprecipitadas; iv) en los tres órdenes de suelos la tercera fracción en orden de importancia fue el Al asociadas a la materia orgánica; v) la menor concentración de fósforo fue hallada en los Alfisoles y la mayor en los Ultisoles y su disponibilidad es afectada principalmente por la presencia de diferentes formas de Fe, Mn, y Al
Catching up with Method and Process Practice: An Industry-Informed Baseline for Researchers
Software development methods are usually not applied by the book.companies are under pressure to continuously deploy software products that meet market needs and stakeholders\u27 requests. To implement efficient and effective development processes, companies utilize multiple frameworks, methods and practices, and combine these into hybrid methods. A common combination contains a rich management framework to organize and steer projects complemented with a number of smaller practices providing the development teams with tools to complete their tasks. In this paper, based on 732 data points collected through an international survey, we study the software development process use in practice. Our results show that 76.8% of the companies implement hybrid methods.company size as well as the strategy in devising and evolving hybrid methods affect the suitability of the chosen process to reach company or project goals. Our findings show that companies that combine planned improvement programs with process evolution can increase their process\u27 suitability by up to 5%
Ebselen enhances insulin sensitivity and decreases oxidative stress by inhibiting SHIP2 and protects from inflammation in diabetic mice
Ebselen, a multifunctional organoselenium compound, has been recognized as a potential treatment for diabetes-related disorders. However, the underlying mechanisms whereby ebselen regulates metabolic pathways remain elusive. We discovered that ebselen inhibits lipid phosphatase SHIP2 (Src homology 2 domain-containing inositol-5-phosphatase 2), an emerging drug target to ameliorate insulin resistance in diabetes. We found that ebselen directly binds to and inhibits the catalytic activity of the recombinant SHIP2 phosphatase domain and SHIP2 in cultured cells, the skeletal muscle and liver of the diabetic db/db mice, and the liver of the SHIP2 overexpressing (SHIP2-Tg) mice. Ebselen increased insulin-induced Akt phosphorylation in cultured myotubes, enhanced insulin sensitivity and protected liver tissue from lipid peroxidation and inflammation in the db/db mice, and improved glucose tolerance more efficiently than metformin in the SHIP2-Tg mice. SHIP2 overexpression abrogated the ability of ebselen to induce glucose uptake and reduce ROS production in myotubes and blunted the effect of ebselen to inhibit SHIP2 in the skeletal muscle of the SHIP2-Tg mice. Our data reveal ebselen as a potent SHIP2 inhibitor and demonstrate that the ability of ebselen to ameliorate insulin resistance and act as an antioxidant is at least in part mediated by the reduction of SHIP2 activity.Peer reviewe
First-Digit Law in Nonextensive Statistics
Nonextensive statistics, characterized by a nonextensive parameter , is a
promising and practically useful generalization of the Boltzmann statistics to
describe power-law behaviors from physical and social observations. We here
explore the unevenness of the first digit distribution of nonextensive
statistics analytically and numerically. We find that the first-digit
distribution follows Benford's law and fluctuates slightly in a periodical
manner with respect to the logarithm of the temperature. The fluctuation
decreases when increases, and the result converges to Benford's law exactly
as approaches 2. The relevant regularities between nonextensive statistics
and Benford's law are also presented and discussed.Comment: 11 pages, 3 figures, published in Phys. Rev.
Aporte y descomposición de hojas y re-absorción de N, P y K en un bosque primario de Schinopsis balansae Engler con y sin manejo silvopastoril en el Parque Chaqueño Húmedo
El objetivo del trabajo fue estudiar: i) el aporte al suelo de la hojarasca proveniente de árboles de Schinopsis balansae Engler, ii) la tasa de descomposición de sus hojas en un bosque primario y con manejo silvopastoril y iii) la relación entre la composición de N, P y K en hojas verdes y secas de esta especie forestal en ambos ecosistemas forestales. Se seleccionaron dos sitios, uno en un monte nativo de 5. balan.me Engler sin intervención humana (MN); y el otro sitio, en un bosque similar sujeto a un manejo silvopastoril (SP). Las hojas senescentes se recolectaron mensualmente en canastos y simultáneamente se muestreaban las hojas verdes de cada árbol. Posteriormente se lavaban, secaban a 70 ºC y se realizaron los análisis de N, P y K foliares. Se detectó que los diferentes tratamientos no impactaron negativamente en el aporte de hojarasca al suelo. Las constantes de descomposición (k) fueron 0, 10 año 1 en MN y 0,12 año· 1 en SP, no detectándose diferencias entre los sitios. Se obtuvieron menores concentraciones de N, P, y K en las hojas senescentes con respecto a las hojas verdes, indicando una re-absorción de los mismos. Las mayores concentraciones foliares registrada5, siguen el orden P > N > K
Distress, depression and coping in HLA-B27-associated anterior uveitis with focus on gender differences
Background/aims To evaluate depression, coping with
disease and stress, and the subjective impression of
distress and/or life events as triggers for recurrences in
HLA-B27-associated anterior uveitis (B27-AU), with
attention to gender-specific characteristics.
Methods 171 patients with a history of B27-AU
responded to a postal survey performed between
January 2006 and April 2008 using standardised
psychological questionnaires: Beck Depression Inventory,
Freiburg Questionnaire on Coping with Illness, and Stress
Coping Inventory.
Results Patients with B27-AU differed from healthy
controls showing more depressive symptoms (Beck
Depression Inventory, 31.6%), applying characteristic
disease coping as well as negative stress coping
strategies. Female B27-AU patients tended to react with
depression and male patients to use negative stress
coping strategies. 57.9% of patients believed that
psychological distress was a trigger for relapses, and
34.5% stated specific life events. Together, this group of
patients achieved higher depression scores and used
more negative disease and stress coping styles than
patients without perception of distress.
Conclusion Patients with B27-AU patients exhibited
significant psychopathology concerning depression and
disease coping. Distress and life events were
subjectively suspected to be a trigger. By imparting
knowledge to the patients on probable development of
depressive moods and the role of stress/life events as
trigger for relapses, as well as offering behaviour therapy
to optimise coping, may help patients to cope better
with B27-AU
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