Debris-flow interaction with slid barriers: efficiency and clogging mechanism

The design of structures for debris flow mitigation is still mostly based on the application of simple, empirical formulas. Standard practice suggests that slit structures might be a convenient solution for partially stopping the flow by filtering out the largest grains, which represent the most hazardous component. However, efforts towards the development of rational approaches for the design of the abovementioned structures have been hindered by the complexity of the debris materials. The interaction between a granular flow composed of monodisperse grains and a slit barrier is in this work reproduced by a discrete numerical model. The model is validated by comparison with a set of experimental runs with an analogous geometry. While the model greatly simplifies reality, it is anyway able to give insight in how clogging, and eventually stoppage, develops. Traditionally, the slit size is prescribed by choosing a multiple of the desired grain size to be stopped. The results highlight how stoppage can be achieved with a relatively wide range of possible slit openings. A family of recurring behaviors is observed, depending on the amount of entrained material and on whether stoppage is instantaneous or delayed. Finally, the initial assumptions are relaxed by moving to a bi-disperse flow. The results of the monodisperse case can be generalized to the bi-disperse case by definition of an equivalent radius

An Efficient Reliability-based Design Approach to Reduce Rockfall Risk Below a Target Threshold

Rockfalls are expected to increase due to global warming and extreme events induced by climate change. An accurate quantification of the risk is fundamental for Administrations to predispose effective risk mitigation plans. Risk value should account for all the possible events that can occur in a specific time, i.e. for a magnitude (block volume) frequency relationship. Among structural protective measures, rockfall barriers are widely selected. Despite their design method has been almost defined, even not standardized, the widely adopted safety factors approach with fixed factors does not allow obtaining a specific probability of failure. Moreover, the event magnitude-frequency relationship is not accounted. A novel time- independent reliability-based approach has been recently conceived by the Authors, allowing obtaining the design values for a specific failure probability. The method accounts for all the possible events, integrating them in time with their probability. In this way, an increase of rockfall events can been accurately considered. The obtained barrier failure probability can be used to compute the risk reduction in a given time or, conversely, to define the maximum failure probability of a barrier that could be accepted

A mixed quantitative approach to evaluate rockfall risk and the maximum allowable traffic on road infrastructure

Rockfall events constitute one of the most dangerous phenomena in mountainous areas, which can affect transportation routes. In a risk mitigation perspective, the quantification of the risk for pedestrians and vehicles represents a crucial aspect for authorities. A method tailored to these elements at risk is herein presented. The proposed method is based on a mixed formulation of the Quantitative Risk Assessment and the Event Tree Analysis approaches. According to these procedures, an accurate evaluation of the annual probability of adverse outcomes can be computed considering all the scenarios which can lead to a fatality or to an injury. Vice versa, the method lets to evaluate the allowable traffic condition, given an acceptable threshold for the risk. Furthermore, it serves to quantify the risk reduction in case of installed passive mitigation measures and, thus, to plan the priority of intervention works. An application on a study case in the Italian Alps illustrates the potentialities of the methodology

Variación genética de poblaciones naturales de Ciprés de la Cordillera con regímenes de precipitación contrastados, en la eficiencia del uso del agua de plántulas, a través de la discriminación isotópica del carbono

Water-use efficiency (WUE) is a physiological parameter that plays a significant role in the evolutionary dynamics of many forest tree species. It can be estimated indirectly through carbon isotope discrimination (Δ). In general, plants of more arid origins have lower values of Δ. In order to study the degree of genetic control of this parameter and the genetic variation in Δ of Patagonian Cypress seedlings, three Argentinean natural populations chosen to represent two contrasting precipitation regimes were sampled in a common garden trial. The dry situation was represented by two neighboring marginal forest patches from the steppe, while the humid condition was represented by a population with 1,200 mm higher mean annual precipitation. Height (H) and Δ were measured in 246 five-year-old seedlings from 41 open-pollinated families. The factor ‘family’ had a significant effect on both variables; however heritability for Δ was found not to be significant in two out of the three populations. This could be explained by low sample size in one of them and by a real evolutionary effect in the other. An inverse association between H and Δ was verified, which is interpreted as evidence of an adaptation process at the intra-population level. The studied populations were not shown to discriminate carbon isotopes differently; hence evidence of adaptation to current environmental conditions could not be obtained. On the other hand, the arid populations proved to be quite different in terms of genetic variation, which seems to be the consequence of genetic drift and isolation.La eficiencia en el uso del agua es un parámetro fisiológico que desempeña un rol significativo en la dinámica evolutiva de muchas especies forestales. Puede estimarse indirectamente a través de la discriminación isotópica del carbono (Δ). En general, las plantas de orígenes más áridos tienen valores de Δ más bajos. Con el propósito de estudiar el grado de control genético de Δ y la variación genética en este parámetro en plántulas de Ciprés de la Cordillera, tres poblaciones naturales elegidas para representar dos regímenes de precipitación contrastados fueron muestreadas en un ensayo de ambiente común. La condición árida estuvo representada por dos fragmentos de bosque esteparios marginales, vecinos entre sí, mientras que la condición húmeda fue representada por una población con una precipitación media anual 1.200 mm superior a la de las áridas. Se midió altura total (H) y Δ en 246 plántulas de 5 años de edad correspondientes a 41 familias de polinización abierta. El factor ‘familia’ tuvo un efecto significativo en ambas variables; sin embargo, la heredabilidad para Δ no resultó significativa en dos de las tres poblaciones. En una de ellas esto podría explicarse por el restringido tamaño muestreal, mientras que en la otra por un verdadero efecto evolutivo. Asimismo se verificó una asociación inversa entre H y Δ, la cual es interpretada como evidencia de un proceso de adaptación a nivel intra-poblacional. No se observó que las poblaciones estudiadas discriminaran los isótopos del carbono de un modo diferencial, y por lo tanto no se obtuvieron evidencias de adaptación a las condiciones ambientales actuales. Por otro lado, las poblaciones áridas probaron ser muy diferentes entre sí en términos de variación genética, lo que parece ser la consecuencia de deriva y aislamiento genéticos

Gene Modulation by Peptide Nucleic Acids (PNAs) Targeting microRNAs (miRs)

Since non-viral gene therapy was developed and employed in different in vitro and in vivo experimental systems as an effective way to control and modify gene expression, RNA has been considered as a molecular target of great relevance (Li &Huang, 2008, López-Fraga et al., 2008). In combination with standard chemotherapy, the siRNA therapy can reduce the chemoresistance of certain cancers, demonstrating its potential for treating many malignant diseases. Examples of RNA sequences to be targeted for therapeutic applications are mRNAs coding oncoproteins or RNA coding anti-apoptotic proteins for the development of anti-cancer therapy. In the last years, progresses in molecular biology have allowed to identify many genes Coding for small non coding RNA molecules, microRNA (miRNAs or miRs), able to regulate gene expression at the translation level (Huang et al., 2008, Shrivastava & Shrivastava, 2008, Sahu et al. 2007, Orlacchio et al., 2007, Williams et al., 2008, Papagiannakopoulos & Kosik, 2008). Accordingly, an increasing number of reports associate the changed expression with specific phenotypes and even with pathological conditions (Garzon & Croce, 2008, Mascellani et al., 2008, Sontheimer & Carthew, 2005, Filipowicz et al., 2005, Alvarez-Garcia & Miska, 2005). Interestingly, microRNAs play a double role in cancer, behaving both as oncogenes or tumor suppressor genes. In general, miRs promoting cancer targets mRNA coding for tumor-suppression proteins, while microRNAs exhibiting tumor-suppression properties usually target mRNAs coding oncoproteins. MicroRNAs which have been demonstrated to play a crucial role in the initiation and progression of human cancer are defined as oncogenic miRNAs (oncomiRs) (Cho, 2007). The oncomiR expression profiling of human malignancies has also identified a number of diagnostic and prognostic cancer signals (Cho, 2007, Lowery et al., 2008). Moreover, microRNAs have been firmly demonstrated to be involved in cancer metastasis (metastamiRs). Examples of metastasis-promoting microRNAs are, miR-10b (Calin et al., 2006), miR-373 and - 520c (Woods et al., 2007), miR-21, -143 and -182 (Hayashita et al., 2005; Si et al., 2007; Zhu et al.,2007). Reviews on metastamiR has been recently published Hurst et al. (Hurst et al. 2009, Edmonds et al. 2009). Reviews on metastamiRs has been recently published by Hurst et al

Increased serum OPG in atrophic nonunion shaft fractures

Background Bone repair alteration is hypothesized for nonunion fracture pathogenesis. Since it is involved in osteoclast regulation, the RANK/RANKL/OPG system (receptor activator of nuclear factor kB/its ligand/osteoprotegerin) may play a role. Materials and methods Serum OPG, free RANKL, bone alkaline phosphatase (BAP), osteocalcin (OC), and urinary deoxypyridinoline (DPD) were determined in 16 male patients (20\u201339 years) with long bone atrophic nonunion fractures. Serum markers were also measured in 18 agematched male controls who healed from the same type of fractures within six months, and in 14 age-matched male controls who were healing from the same fractures one month after injury. One-way ANOVA and Bonferroni\u2019s test were used for statistical analysis. Results Only OPG was significantly higher (0.56 sd 0.11 ng/ml) in the patients compared to healed (0.26 sd 0.04 ng/ml; P\0.001) and healing (0.29 sd 0.09 ng/ml; P\0.001) controls. The patients\u2019 DPD levels were normal. No correlations were found between bone markers and the characteristics of the subjects in all groups. Conclusions A normal steady state of bone metabolism seems to be present in patients with atrophic nonunion fractures, despite the high serum OPG. The reason for the inability of the patients\u2019 OPG to inhibit osteoclastic activity is unknown. Osteoblast activity also appears normal, so another cellular source of OPG can be hypothesized

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to ♀EFAX™ and reduction of menstrual discomfort pursuant to Article 13(5) of Regulation (EC) No 1924/2006

Following an application from Nutrilinks Sarl submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Cyprus, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to ♀EFAX™ and reduction of menstrual discomfort. The food, ♀EFAX™, which is standardised pure krill oil and is the subject of the health claim, is sufficiently characterised. The claimed effect, reduction of menstrual discomfort, is a beneficial physiological effect. No human intervention studies from which conclusions could be drawn for the scientific substantiation of the claim were provided by the applicant. A cause and effect relationship has not been established between the consumption of ♀EFAX™ and reduction of menstrual discomfort