Application of asymptotic waveform evaluation for time domain analysis of nonlinear circuits

Cataloged from PDF version of article.A method is described to exploit asymptotic waveform evaluation (ATNE) in the time-domain analysis of nonlinear circuits by using SPICE models for nonlinear devices such as diodes, transistors, etc. Although AWE has been used for linearized circuits only, the aim is to enhance the accuracy of the simulation while preserving the computational efficiency obtained with AWE and to eliminate the piecewise-linear modelling problem. Practical examples are given to illustrate significant improvements in accuracy. For circuits containing weakly nonlinear devices, it is demonstrated that this method is typically at least one order of magnitude faster than SPICE

A novel algorithm for DC analysis of piecewise-linear circuits: popcorn

Cataloged from PDF version of article.A fast and convergent iteration method for piecewise-linear analysis of nonlinear resistive circuits is presented. Most of the existing algorithms are applicable only to a limited class of circuits. In general, they are either not convergent or too slow for large circuits. The new algorithm presented in the paper is much more efficient than the existing ones and can be applied to any piecewise-linear circuit. It is based on the piecewise-linear version of the Newton-Raphson algorithm. As opposed to the Newton-Raphson method, the new algorithm is globally convergent from an arbitrary starting point. It is simple to understand and it can be easily programmed. Some numerical examples are given in order to demonstrate the effectiveness of the proposed algorithm in terms of the amount of computation

Modelling for water management: first calibration of yield-SAFE for irrigated maize in Mediterranean regions

In the Mediterranean region, careful management of water and nitrogen utilization is required to achieve high crop yields in a sustainable and economic way. Prediction models are useful tools for deriving site/region–specific optimum management strategies for irrigation and nitrogen use. Yield-SAFE, a simple and robust model for growth and resource use in agroforestry systems, simulates crop yields under rainfed and irrigated conditions. This paper represents a refined calibration with respect to the fluxes of water, based on, data from an irrigation/fertilisation experiment with maize in the South-East of Turkey. The model performs satisfactorily and further development will includede nitrogen leaching calibration and validation

Caregiving in multiple sclerosis and quality of life: a meta-synthesis of qualitative research

Objective: The lack of adequate conceptualisation and operationalisation of quality of life (QoL) limits the ability to have a consistent body of evidence to improve QoL research and practice in informal caregiving for people with multiple sclerosis (MS). Thus, we conducted a meta-synthesis of qualitative research to improve the conceptual understanding of the experiences of MS carers and to identify factors that affect carers' QoL. Design: Systematic searches of five electronic databases yielded 17 qualitative studies which were synthesised using the principles of meta-ethnography. Results: The synthesis resulted in nine inter-linking themes: Changes and losses; challenges revolving around MS; caregiving demands; burden of care; future concerns; external stressors; experiences of support; strategies used in managing the caregiving role; and motivating factors. Our findings suggest that MS carers can have both positive and negative experiences which may bring challenges and rewards to the carers. Conclusion: We present a proposed QoL model for MS caregiving which can be used to inform the development of interventions for MS carers to improve their QoL. However, further empirical research is needed to examine the utility of this model and to explore the concept of QoL in MS carers in more detail

Ammonium and nitrate status of the first crop corn fields at Cukurova region

The ammonium (NH4) and nitrate (NO3) are the available nitrogen (N) forms that plants need in large quantities. Their existence in the soil is limited, and concentrations are kept low due to the losses by leaching in the soil profile and microbial consumptions. Sustainability of the plant available nitrogen forms in soil profile is important for plant growth and crop production. In this research, our main objective was to evaluate mineral nitrogen (Nmin) status of the first crop corn soils and plants in Akarsu Irrigation District of Cukurova Region in 2007. Soil samples prior to sowing and after harvest were taken from 0-30, 30-60 and 60-90 cm soil depths, and analyzed for ammonium and nitrate concentrations. Plant samples were also taken during harvest, and analyzed for N content for determination of total N uptake. There was considerable amount of ammonium and nitrate in the soil profile during preplanting and postharvest. Since the soils were mostly heavy texture, there is tendency to have ammonium also in the soil solution. However, ammonium concentration was far below the nitrate concentration throughout the profile. Plant nitrogen uptake in the irrigation district was very close to the amount that was applied by the local farmers. The results indicated that soil mineral nitrogen level is an important criteria for fertilization practices, especially the preplant Nmin values need to be considered to decrease the amount of N fertilizer that will be applied

The nation in context: how intergroup relations shape the discursive construction of identity continuity and discontinuity

The perceived collective continuity (PCC) of a national identity serves as a crucial source of stability and self‐esteem for group members. Recent work has explored the consequences of perceived continuity when the meaning of a nation’s past is seen in a negative light, and the challenges this brings for the negotiation of a positive identity in the present, signalling the potential value of perceived discontinuity The current paper extends this literature by examining the role of intergroup relations in the construction of both collective continuities and discontinuities. Through analysing the discursive management of national identity in nine focus groups in a post‐conflict context (Serbia, N = 67), we reveal how the tensions between continuity and discontinuity are embedded within a broader discussion of the nation’s relationship with relevant national outgroups across its history. The findings contribute to theoretical knowledge on the interlinking of national identity and PCC by illustrating the ways in which intergroup relations of the past shape the extent to which continuity is seen as desirable or undesirable. We argue that despite the psychological merits of collective continuity, discontinuity can become attractive and useful when there is limited space to challenge how a nation’s history is remembered and the valence given to the past. The paper concludes by offering an account of how social and political contexts can influence the nature, functions, and valence of PCC within national identities

The Role of MeCP2 in Brain Development and Neurodevelopmental Disorders

Methyl CpG binding protein-2 (MeCP2) is an essential epigenetic regulator in human brain development. Rett syndrome, the primary disorder caused by mutations in the X-linked MECP2 gene, is characterized by a period of cognitive decline and development of hand stereotypies and seizures following an apparently normal early infancy. In addition, MECP2 mutations and duplications are observed in a spectrum of neurodevelopmental disorders, including severe neonatal encephalopathy, X-linked mental retardation, and autism, implicating MeCP2 as an essential regulator of postnatal brain development. In this review, we compare the mutation types and inheritance patterns of the human disorders associated with MECP2. In addition, we summarize the current understanding of MeCP2 as a central epigenetic regulator of activity-dependent synaptic maturation. As MeCP2 occupies a central role in the pathogenesis of multiple neurodevelopmental disorders, continued investigation into MeCP2 function and regulatory pathways may show promise for developing broad-spectrum therapies

Collaborative database to track Mass Mortality Events in the Mediterranean Sea

Anthropogenic climate change, and global warming in particular, has strong and increasing impacts on marine ecosystems (Poloczanska et al., 2013; Halpern et al., 2015; Smale et al., 2019). The Mediterranean Sea is considered a marine biodiversity hotspot contributing to more than 7% of world\u2019s marine biodiversity including a high percentage of endemic species (Coll et al., 2010). The Mediterranean region is a climate change hotspot, where the respective impacts of warming are very pronounced and relatively well documented (Cramer et al., 2018). One of the major impacts of sea surface temperature rise in the marine coastal ecosystems is the occurrence of mass mortality events (MMEs). The first evidences of this phenomenon dated from the first half of \u201980 years affecting the Western Mediterranean and the Aegean Sea (Harmelin, 1984; Bavestrello and Boero, 1986; Gaino and Pronzato, 1989; Voultsiadou et al., 2011). The most impressive phenomenon happened in 1999 when an unprecedented large scale MME impacted populations of more than 30 species from different phyla along the French and Italian coasts (Cerrano et al., 2000; Perez et al., 2000). Following this event, several other large scale MMEs have been reported, along with numerous other minor ones, which are usually more restricted in geographic extend and/or number of affected species (Garrabou et al., 2009; Rivetti et al., 2014; Marb\ue0 et al., 2015; Rubio-Portillo et al., 2016, authors\u2019 personal observations). These events have generally been associated with strong and recurrent marine heat waves (Crisci et al., 2011; Kersting et al., 2013; Turicchia et al., 2018; Bensoussan et al., 2019) which are becoming more frequent globally (Smale et al., 2019). Both field observations and future projections using Regional Coupled Models (Adloff et al., 2015; Darmaraki et al., 2019) show the increase in Mediterranean sea surface temperature, with more frequent occurrence of extreme ocean warming events. As a result, new MMEs are expected during the coming years. To date, despite the efforts, neither updated nor comprehensive information can support scientific analysis of mortality events at a Mediterranean regional scale. Such information is vital to guide management and conservation strategies that can then inform adaptive management schemes that aim to face the impacts of climate change

Multiplicity: an organizing principle for cancers and somatic mutations

<p>Abstract</p> <p>Background</p> <p>With the advent of whole-genome analysis for profiling tumor tissue, a pressing need has emerged for principled methods of organizing the large amounts of resulting genomic information. We propose the concept of multiplicity measures on cancer and gene networks to organize the information in a clinically meaningful manner. Multiplicity applied in this context extends Fearon and Vogelstein's multi-hit genetic model of colorectal carcinoma across multiple cancers.</p> <p>Methods</p> <p>Using the Catalogue of Somatic Mutations in Cancer (COSMIC), we construct networks of interacting cancers and genes. Multiplicity is calculated by evaluating the number of cancers and genes linked by the measurement of a somatic mutation. The Kamada-Kawai algorithm is used to find a two-dimensional minimum energy solution with multiplicity as an input similarity measure. Cancers and genes are positioned in two dimensions according to this similarity. A third dimension is added to the network by assigning a maximal multiplicity to each cancer or gene. Hierarchical clustering within this three-dimensional network is used to identify similar clusters in somatic mutation patterns across cancer types.</p> <p>Results</p> <p>The clustering of genes in a three-dimensional network reveals a similarity in acquired mutations across different cancer types. Surprisingly, the clusters separate known causal mutations. The multiplicity clustering technique identifies a set of causal genes with an area under the ROC curve of 0.84 versus 0.57 when clustering on gene mutation rate alone. The cluster multiplicity value and number of causal genes are positively correlated via Spearman's Rank Order correlation (<it>r_s</it>(8) = 0.894, Spearman's <it>t </it>= 17.48, <it>p </it>< 0.05). A clustering analysis of cancer types segregates different types of cancer. All blood tumors cluster together, and the cluster multiplicity values differ significantly (Kruskal-Wallis, <it>H </it>= 16.98, <it>df </it>= 2, <it>p </it>< 0.05).</p> <p>Conclusion</p> <p>We demonstrate the principle of multiplicity for organizing somatic mutations and cancers in clinically relevant clusters. These clusters of cancers and mutations provide representations that identify segregations of cancer and genes driving cancer progression.</p