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

Teichm\"uller's problem in space

Quasiconformal homeomorphisms of the whole space Rn, onto itself normalized at one or two points are studied. In particular, the stability theory, the case when the maximal dilatation tends to 1, is in the focus. Our main result provides a spatial analogue of a classical result due to Teichm\"uller. Unlike Teichm\"uller's result, our bounds are explicit. Explicit bounds are based on two sharp well-known distortion results: the quasiconformal Schwarz lemma and the bound for linear dilatation. Moreover, Bernoulli type inequalities and asymptotically sharp bounds for special functions involving complete elliptic integrals are applied to simplify the computations. Finally, we discuss the behavior of the quasihyperbolic metric under quasiconformal maps and prove a sharp result for quasiconformal maps of R^n \ {0} onto itself.Comment: 25 pages, 2 figure

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

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%

Efecto del uso de media sombra y manta anti helada en lechuga (Lactuca sativa) de invierno

Lettuce is considered the most consumed vegetable in the country which grows throughout the year. The aim of this work was to evaluate the effect of the shading net and floating row covers on the yield and leaf appearance in winter lettuce. The trial was carried out in EEA INTA Colonia Benítez, Chaco on Argiudol oxic soil. The crop was cultivated under three different conditions, 50% shade net, floating row covers and in open sky. The sowing date was on 06/06/2012 using the cv. Grand Rapid and distances of 0.40 m between rows and 0.25 m between plants. The harvesting and yield determination were at 77 DAS. In each situation, soil temperature and PAR were measured.  The results showed the highest yields in open sky, followed by floating row covers and the lowest yield in shadde net 50%. The average PAR was higher in open sky conditions, followed by floating row covers and 50% shade net, while  soil temperature showed values within the optimal range for cultivation in the three treatments being higher in the floating row covers one. These results evidenced that the use of 50% shade net reduced the yield in winter conditions in Colonia Benítez (Chaco),  which was not the case of floating row covers.La lechuga se caracteriza por ser una de las principales hortalizas consumidas en el país y por cultivarse durante todo el año. El objetivo del trabajo fue evaluar el efecto de la media sombra y manta anti helada sobre el rendimiento y aparición de hojas en un cultivo de lechuga invernal. El ensayo se realizó en la EEA INTA Colonia Benítez, Chaco sobre un suelo clasificado como Argiudol óxico. El cultivo se realizó bajo tres condiciones diferentes, media sombra 50%, manta anti helada y a cielo abierto. La siembra de lechuga se realizó el 06/06/2012 utilizándose el cv. Grand Rapid y distancias de 0,40 m entre líneos y de 0,25 entre plantas. A los 77 DDS se procedió a la cosecha y determinación del rendimiento. En cada situación de cultivo se midió temperatura de suelo y radiación PAR. Los resultados mostraron los mayores rendimientos en el cultivo a cielo abierto, seguido por manta anti helada y el menor rendimiento bajo media sombra 50%. La media de la radiación PAR fue superior en condiciones de cielo abierto, seguido por manta anti helada y media sombra 50%, por su parte la temperatura de suelo mostró valores dentro del rango óptimo para el cultivo en los tres tratamientos siendo mayor en el tratamiento manta anti helada. Estos resultados evidencian que para las condiciones de invierno en Colonia Benítez (Chaco) el uso de media sombra al 50% disminuyó el rendimiento, no así con el uso de manta anti helada

First-Digit Law in Nonextensive Statistics

Nonextensive statistics, characterized by a nonextensive parameter $q$, 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 $q$ increases, and the result converges to Benford's law exactly as $q$ 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.

The Influence of Brightness on Functional Assessment by mfERG: A Study on Scaffolds Used in Retinal Cell Transplantation in Pigs

To determine the effect of membrane brightness on multifocal electroretinograms (mfERGs), we implanted poly lactic-co-glycolic acid (PLGA) membranes in the subretinal space of 11 porcine eyes. We compared membranes with their native shiny white color with membranes that were stained with a blue dye (Brilliant Blue). Histological and electrophysiological evaluation of the overlying retina was carried out 6 weeks after implantation. Histologically, both white and blue membranes degraded in a spongiform manner leaving a disrupted outer retina with no preserved photoreceptor segments. Multifocal ERG revealed the white membranes to have a significantly higher P1-amplitude ratio than the blue (P = 0.027), and a correlation between brightness ratio and P1-amplitude ratio was found (r = 0.762). Based on our findings, we conclude that bright subretinal objects can produce normal mfERG amplitude ratios even when the adjacent photoreceptors are missing. Functional assessment with mfERG in scaffold implant studies should therefore be evaluated with care

Subretinal Implantation of Electrospun, Short Nanowire, and Smooth Poly(ε-caprolactone) Scaffolds to the Subretinal Space of Porcine Eyes

Biodegradable scaffolds play an important adjunct role in transplantation of retinal progenitor cells (RPCs) to the subretinal space. Poly(ε-Caprolactone) (PCL) scaffolds with different modifications were subretinally implanted in 28 porcine eyes and evaluated by multifocal electroretinography (mfERG) and histology after 6 weeks of observation. PCL Short Nanowire, PCL Electrospun, and PCL Smooth scaffolds were well tolerated in the subretinal space in pigs and caused no inflammation and limited tissue disruption. PCL Short Nanowire had an average rate of preserved overlying outer retina 17% higher than PCL Electrospun and 25% higher than PCL Smooth. Furthermore, PCL Short Nanowire was found to have the most suitable degree of stiffness for surgical delivery to the subretinal space. The membrane-induced photoreceptor damage could be shown on mfERG, but the reductions in P1 amplitude were only significant for the PCL Smooth. We conclude that of the tested scaffolds, PCL Short Nanowire is the best candidate for subretinal implantation

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