The Power-law Tail Exponent of Income Distributions

In this paper we tackle the problem of estimating the power-law tail exponent of income distributions by using the Hill's estimator. A subsample semi-parametric bootstrap procedure minimising the mean squared error is used to choose the power-law cutoff value optimally. This technique is applied to personal income data for Australia and Italy.Comment: Latex2e v1.6; 8 pages with 3 figures; in press (Physica A

Producing viruses in orbit: Current developments for orbital shaken viral vaccine manufacturing

Preculture of suspension cells is successfully performed in shake flasks. Especially newly developed designer cells are passaged up to 100 times in shake flaks at high shaking frequency and are then perfectly adapted to growth in a CO2 incubator with pH control and maximum oxygen supply (typically above 80% pO2). When they are subsequently transferred to stirred tank bioreactors for scaling up, specific cell growth rates are often lower and cells become sensitive to pH control via acid/base addition and shear stress due to submers gassing (bubbles). This was also seen for avian AGE1.CR.pIX and human HEK 293 cells. To avoid these problems, scale up in shaken mode was evaluated. Here we present the latest developments of the SB10-X OSB bioreactor with regard to bag design and improvement of the control unit. A new control strategy was introduced leading to a faster and more precise pH and DO control. Furthermore, the perfusion bag was optimized, so that on TFF or two ATF systems can be easily connected. Both developments have led to a more robust SB10-X system that allows to easily perform batch, fed batch or perfusion runs. Please click Download on the upper right corner to see the full abstract

Variable order Mittag-Leffler fractional operators on isolated time scales and application to the calculus of variations

We introduce new fractional operators of variable order on isolated time scales with Mittag-Leffler kernels. This allows a general formulation of a class of fractional variational problems involving variable-order difference operators. Main results give fractional integration by parts formulas and necessary optimality conditions of Euler-Lagrange type.Comment: This is a preprint of a paper whose final and definite form is with Springe

Estimativa do custo do primeiro desbaste de Prosopis alba: metodologia aplicada ao caso de uma plantação em Herrera, Santiago del Estero, Argentina

The first forest thinning operation at a five-year-old algarrobo blanco (Prosopis alba) commercial plantation in Herrera (Department of Avellaneda) in the province of Santiago del Estero, Argentina was analyzed using a time and movement study to determine operational productivity and costs associated with the shoring process using a chainsaw. Effective and operative times were measured and the volume was calculated with respect to bark, efficiency, productivity and the direct cost of thinning. The sample of 226 trees had a cut volume of 1.19 m3. The average operative time was 77 s/tree and the median effective time was 49 s/tree. A strong correlation was found between the effective working time with the tool and the variables for greater diameter and volume of the trees. The operational efficiency was 63.3%. Productivity per hour when felling trees was 0.25 m3/h (47 trees/h). The daily cost of the operation was 781 $/day, and the unit thinning cost was 527$/m3 (1 US$= 8.12$ in May of 2014).Se analizó la operación del primer raleo forestal en una plantación comercial de algarrobo blanco (Prosopis alba) de 5 años de edad, en la localidad de Herrera (Dpto. Avellaneda) de la provincia de Santiago del Estero, Argentina, mediante un estudio de tiempos y movimientos para conocer la productividad operacional y los costos asociados al proceso de apeo con motosierra. Se midieron tiempos efectivos y operativos y se calculó volumen con corteza, eficiencia, productividad y costo directo del raleo. La muestra de 226 árboles completó un volumen abatido de 1,19 m3. El tiempo operativo promedio fue 77 s/árbol y el tiempo efectivo medio de 49 s/árbol. Se verificó una fuerte correlación entre el tiempo efectivo de trabajo de la herramienta y las variables diámetro mayor y volumen de los árboles. La eficiencia operacional fue del 63,3%. La productividad horaria en el derribo fue de 0,25 m3/h (47 árboles/h). El costo diario de la operación fue de 781 $/día, mientras que el costo unitario del raleo fue de 527$/m3 (1 US$= 8,12$ en mayo 2014).Analisou-se a operação do primeiro desbaste florestal numa plantação comercial de Prosopis alba de cinco anos de idade, em Herrera (Avellaneda) da província de Santiago del Estero (Argentina), mediante um estudo de tempos e movimentos para conhecer a produtividade operacional e os custos associados ao processo de abate com motosserra. Mediram-se tempos efetivos e operativos e calcularam-se volume com corte, eficiência, produtividade e custo direto do desbaste. A amostra de 226 árvores completou um volume abatido de 1,19 m3. O tempo operativo médio foi de 77s/árvore e o tempo efetivo médio de 49 s/árvore. Verificou-se uma forte correlação entre o tempo efetivo de trabalho da ferramenta e as variáveis diâmetro maior e volume das árvores. A eficiência operacional foi de 63,3%. A produtividade horária na derrubada foi de 0,25 m3/h (47 árvores/h). O custo diário da operação foi de 781$por dia, enquanto o custo unitário do desbaste foi de 527$/m3 (1 US$= 8,12$ em maio 2014)

Emerging properties of financial time series in the “Game of Life”

We explore the spatial complexity of Conway’s “Game of Life,” a prototypical cellular automaton by means of a geometrical procedure generating a two-dimensional random walk from a bidimensional lattice with periodical boundaries. The one-dimensional projection of this process is analyzed and it turns out that some of its statistical properties resemble the so-called stylized facts observed in financial time series. The scope and meaning of this result are discussed from the viewpoint of complex systems. In particular, we stress how the supposed peculiarities of financial time series are, often, overrated in their importance