Lightfield Recovery from Its Focal Stack

The Focal Stack Transform integrates a 4D lightfield over a set of appropriately chosen 2D planes. The result of such integration is an image focused on a determined depth in 3D space. The set of such images is the Focal Stack of the lightfield. This paper studies the existence of an inverse for this transform. Such inverse could be used to obtain a 4D lightfield from a set of images focused on several depths of the scene. In this paper, we show that this inversion cannot be obtained for a general lightfield and introduce a subset of lightfields where this inversion can be computed exactly. We examine the numerical properties of such inversion process for general lightfields and examine several regularization approaches to stabilize the transform. Experimental results are provided for focal stacks obtained from several plenoptic cameras. From a practical point of view, results show how this inversion procedure can be used to recover, compress, and denoise the original 4D lightfield.     

Stagnant Effective Thermal Conductivity of Agro-Industrial Residues for Solid-State Fermentation

The stagnant effective thermal conductivities (K₀) of sugar cane bagasse (SCB), wheat bran (WB), orange pulp and peel (OPP) and their combination (weight proportion 1:2:2 SCB/OPP/WB) were obtained using the line heat source method. These solid materials were applied to pectinase production via solid-state fermentation. The moisture content ranged from 4 to 80% (w.b.). A conduction mechanism through the porous media was observed, along with conduction through a liquid film and contact thermal resistance between the samples and the probe. K₀ was low for intermediate moisture contents and approached the molecular conductivity of water for high moisture contents.     

Effects of discharge-forming gases on the antibacterial sensitivity of plasma-reduced silver impregnated in natural zeolites

The influence of plasma-forming gases such as argon and oxygen in the reduction of silver ions (\({\text {Ag}}^+\)) infused into a natural zeolite framework has been investigated for antibacterial applications. Impregnation by soaking and ion exchange were combined with 13.56 MHz radio-frequency plasma to reduce \({\text {Ag}}^+\) to their metallic state for a greener and energy-efficient process. The plasma treatment of the silver zeolite (AgZ) composites did not alter the crystalline structure of the zeolite, while successfully reducing \({\text {Ag}}^+\) to its metallic form as a nanoparticle encapsulated by the zeolite. The antibacterial index of the AgZ composites against Staphylococcus aureus and Escherichia coli confirmed the fervent antibacterial activity of plasma-reduced Ag NP embedded in the zeolite matrix against the two bacterial strains. The highest activity belongs to the samples treated with oxygen plasma. This result is related to increased active area of contact and the incorporation of reactive oxygen species in the zeolite matrix, which contributed to the antibacterial sensitivity of the plasma-treated AgZ.     

Hydrological classification of non-perennial Mediterranean rivers and streams: A new insight for their management within the water framework directive

Classification of natural flow regimes of non-perennial rivers and streams (NPRS) is an incipient field of research. NPRS represent approximately 70% of the total Mediterranean rivers and are expected to increase in the next decades as a result of climate change. Due to the ecological importance of NPRS and the need to improve national ecological assessment methods within the scope of the Water Framework Directive (WFD), this paper aims to classify the hydrological regime of 69 non-regulated streams, testing several hydrological indices related to the magnitude, frequency, duration, timing, and rate of change in periods of flow cessation. Using daily flow records, a total of 315 indices were calculated and their relationships were examined with Principal Component Analysis (PCA) for different thresholds used to define zero-flow condition (0, 1, 2, and 5 L/s). Redundancy analysis identified five indices that better describe the patterns of hydrological variability in Mediterranean NPRS: number of days per year without flow, annual percentage of months without flow, mean daily annual flow, coefficient of variation of Julian date of the annual start of zero-flow and annual rise rate. Using these indices, a self-organizing map (SOM) was trained in order to categorize the NPRS into three groups with similar hydrological features. The results of this study provide a statistically-based hydrological classification of NPRS in Mediterranean environments. We expect that this classification will provide useful insights to water authorities to improve the assessments of the ecological status in this type of water bodies.     

Towards Collaboration Maturity in Business Processes: An Exploratory Study in Oil Production Processes

Abstract

Organizations have been relying on collaboration for knowledge sharing and productivity improvement in order to reduce costs or boost revenue. However, organizations still cannot assure that collaboration is properly conducted in daily work. This paper presents an approach to stimulating collaboration between professionals in an organization. The approach, combining a BPM methodology with the CollabMM collaboration maturity model and its corresponding method, is a result of an exploratory study in a real setting in an oil company in Brazil. The project is a move towards improving decision-making during one of the company's business processes and establishing collaboration among professionals through information sharing.     

Friction and Wear Behavior of Multilayer [Al/AlN]n Coatings Deposited on AISI52100 Steel

Protection of Metals and Physical Chemistry of Surfaces - In this study, a set of multilayer hard nanocrystalline coatings of Al/AlN with 35, 55 and 75 bilayer were prepared by DC magnetron...     

Dickkopf-1 Inhibition Reactivates Wnt/β-Catenin Signaling in Rhabdomyosarcoma,Induces Myogenic Markers In Vitro and Impairs Tumor Cell Survival In Vivo

The Wnt/β-catenin signaling pathway plays a pivotal role during embryogenesis and its deregulation is a key mechanism in the origin and progression of several tumors. Wnt antagonists have been described as key modulators of Wnt/β-catenin signaling in cancer, with Dickkopf-1 (DKK-1) being the most studied member of the DKK family. Although the therapeutic potential of DKK-1 inhibition has been evaluated in several diseases and malignancies, little is known in pediatric tumors. Only a few works have studied the genetic inhibition and function of DKK-1 in rhabdomyosarcoma. Here, for the first time, we report the analysis of the therapeutic potential of DKK-1 pharmaceutical inhibition in rhabdomyosarcoma, the most common soft tissue sarcoma in children. We performed DKK-1 inhibition via shRNA technology and via the chemical inhibitor WAY-2626211. Its inhibition led to β-catenin activation and the modulation of focal adhesion kinase (FAK), with positive effects on in vitro expression of myogenic markers and a reduction in proliferation and invasion. In addition, WAY-262611 was able to impair survival of tumor cells in vivo. Therefore, DKK-1 could constitute a molecular target, which could lead to novel therapeutic strategies in RMS, especially in those patients with high DKK-1 expression.     

Spatial Variation of Woody Riparian Vegetation across the Riverbank Topographic Gradient in Mediterranean Rivers: Species and Growth Categories

The composition and structure of riparian vegetation are linked to the natural hydrological variability and variation of environmental parameters in several spatial scales. The objective of this study is to determine the relationship between the spatial distribution of the woody riparian vegetation and the variation in the riverbank topographic gradient, verifying whether this variation was significant between species and/or growth categories. Specifically, our research examined the location of the woody species with respect to the thalweg along two reaches of the Jarama River in Central Spain. The positioning variables of each individual and distance and elevation above the thalweg were evaluated for four growth categories using statistical analysis. This study revealed that the positioning of the species along reaches is not random and differs with the species and growth categories. In addition, groups of species were specified in the different growth categories using similar positioning patterns with respect to the thalweg. Examples of similar groups of species in a specifically growth category were as follows: Alnus glutinosa–Salix alba–Salix fragilis for one reach and Alnus glutinosa–Populus nigra–Salix alba–Salix salviifolia for the other one. Topographical preference ranges of the riparian species and groups of the Jarama River were also obtained. The integration of data relative to the distribution of species along the topographic gradient can be very useful in identifying species with a preference for specific locations and can also contribute to the success of the measures adopted to restore these frequently highly degraded environments. Copyright © 2015 John Wiley & Sons, Ltd.