A constrained pressure-temperature residual (CPTR) method for non-isothermal multiphase flow in porous media

For both isothermal and thermal petroleum reservoir simulation, the Constrained Pressure Residual (CPR) method is the industry-standard preconditioner. This method is a two-stage process involving the solution of a restricted pressure system. While initially designed for the isothermal case, CPR is also the standard for thermal cases. However, its treatment of the energy conservation equation does not incorporate heat diffusion, which is often dominant in thermal cases. In this paper, we present an extension of CPR: the Constrained Pressure-Temperature Residual (CPTR) method, where a restricted pressure-temperature system is solved in the first stage. In previous work, we introduced a block preconditioner with an efficient Schur complement approximation for a pressure-temperature system. Here, we extend this method for multiphase flow as the first stage of CPTR. The algorithmic performance of different two-stage preconditioners is evaluated for reservoir simulation test cases.Comment: 28 pages, 2 figures. Sources/sinks description in arXiv:1902.0009

A block preconditioner for non-isothermal flow in porous media

In petroleum reservoir simulation, the industry standard preconditioner, the constrained pressure residual method (CPR), is a two-stage process which involves solving a restricted pressure system with Algebraic Multigrid (AMG). Initially designed for isothermal models, this approach is often used in the thermal case. However, it does not have a specific treatment of the additional energy conservation equation and temperature variable. We seek to develop preconditioners which better capture thermal effects such as heat diffusion. In order to study the effects of both pressure and temperature on fluid and heat flow, we consider a model of non-isothermal single phase flow through porous media. For this model, we develop a block preconditioner with an efficient Schur complement approximation. Both the pressure block and the approximate Schur complement are approximately inverted using an AMG V-cycle. The resulting solver is scalable with respect to problem size and parallelization.Comment: 35 pages, 3 figure

Expression of Kv3.1b potassium channel is widespread in macaque motor cortex pyramidal cells: A histological comparison between rat and macaque

There are substantial differences across species in the organisation and function of the motor pathways. These differences extend to basic electrophysiological properties. Thus, in rat motor cortex, pyramidal cells have long duration action potentials, while in the macaque, some pyramidal neurons exhibit short duration 'thin' spikes. These differences may be related to the expression of the fast potassium channel Kv3.1b, which in rat interneurons is associated with generation of thin spikes. Rat pyramidal cells typically lack these channels, while there are reports that they are present in macaque pyramids. Here we made a systematic, quantitative comparison of the expression of Kv3.1b in sections from macaque and rat motor cortex, using two different antibodies (NeuroMab, Millipore). As our standard reference, we examined, in the same sections, Kv3.1b staining in parvalbumin-positive interneurons, which show strong Kv3.1b immunoreactivity. In macaque motor cortex, a large sample of pyramidal neurons were nearly all found to express Kv3.1b in their soma membranes. These labelled neurons were identified as pyramidal based either by expression of SMI32 (a pyramidal marker), or by their shape and size, lack of expression of parvalbumin (a marker for some classes of interneuron). Large (Betz cells), medium and small pyramidal neurons all expressed Kv3.1b. In rat motor cortex, SMI32-postive pyramidal neurons expressing Kv3.1b were very rare and weakly stained. Thus, there is a marked species difference in the immunoreactivity of Kv3.1b in pyramidal neurons, and this may be one of the factors explaining the pronounced electrophysiological differences between rat and macaque pyramidal neurons

Developing and Implementing the Massachusetts Comprehensive Cancer Control Coalition Survivorship Summit

Cancer survivors face numerous medical and psychosocial challenges, which the medical and public health systems are ill-equipped to deal with. In May 2008, the Massachusetts Comprehensive Cancer Control Coalition conducted a Survivorship Summit to elicit input from cancer survivors and professionals on developing system-level action plans for cancer survivorship issues. We describe how health care and public health professionals can implement similar events. Our results suggest that a cancer survivorship summit can be a valuable tool for cancer coalitions and advocacy organizations in determining survivorship agendas and action plans

A validated model of GAG deposition, cell distribution, and growth of tissue engineered cartilage cultured in a rotating bioreactor

The purpose of this article is to review the different strategies for the delivery of plasmid DNA (pDNA)-based gene therapy. Plasmids are extrachromosomal DNA capable of being transmitted from cell to cell. They are supercoiled, circular covalently closed (ccc) strands of DNA capable of replication independently of host DNA and ranging from 5 to 400 kilo base pairs (kb) in size, depending on the size of the therapeutic gene insert

From smart to intelligent cities: learning for sustainability

Smart city development is a strategy to address problems caused by rapid urbanization and socio-economic challenges. While the notion of a ‘smart’ city is ubiquitous, this paper argues that what is needed is not a city where managerial responsibilities have been handed over to ICT, but rather to conceptualise the city as an ecosystem. This perspective posits the city as a complex adaptive system, a cognitive city, which adaptively learns via urban planners and managers. With reference to the Covid-19 pandemic and the UK response, we recognise various constraints to human judgement and decision making under complex conditions, and advocate the contribution of in silico simulations and controlled experiments to test future threats and response scenarios. These facilitate identifying unsustainable future trajectories and the development of alternative strategic opportunities to foster building systemic resilience in anticipating future shocks, and that doing so is an ethical necessity to conserve the viability of future city systems

Habitat corridors facilitate genetic resilience irrespective of species dispersal abilities or population sizes

Corridors are frequently proposed to connect patches of habitat that have become isolated due to human‐mediated alterations to the landscape. While it is understood that corridors can facilitate dispersal between patches, it remains unknown whether corridors can mitigate the negative genetic effects for entire communities modified by habitat fragmentation. These negative genetic effects, which include reduced genetic diversity, limit the potential for populations to respond to selective agents such as disease epidemics and global climate change. We provide clear evidence from a forward‐time, agent‐based model (ABM) that corridors can facilitate genetic resilience in fragmented habitats across a broad range of species dispersal abilities and population sizes. Our results demonstrate that even modest increases in corridor width decreased the genetic differentiation between patches and increased the genetic diversity and effective population size within patches. Furthermore, we document a trade‐off between corridor quality and corridor design whereby populations connected by high‐quality habitat (i.e., low corridor mortality) are more resilient to suboptimal corridor design (e.g., long and narrow corridors). The ABM also revealed that species interactions can play a greater role than corridor design in shaping the genetic responses of populations to corridors. These results demonstrate how corridors can provide long‐term conservation benefits that extend beyond targeted taxa and scale up to entire communities irrespective of species dispersal abilities or population sizes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111750/1/eva12255.pd

Mere Measurement “Plus”: How Solicitation of Open-Ended Positive Feedback Influences Customer Purchase Behavior

In two studies (a longitudinal field experiment with an established B2C national chain, and a field experiment with a B2B software manufacturer), we demonstrate that starting a survey with an open-ended positive solicitation increases customer purchase behavior. Study 1, a longitudinal field experiment, showed that one-year following the completion of a survey that began by asking customers what went well during their purchase experience, customers spent 8.25% more than customers who completed a survey that did not include the positive solicitation. In Study 2, we utilized multiple treatment groups to assess the step-wise gains of solicitation, measurement, and solicitation frame. The results demonstrated (a) a mere solicitation effect, (b) a traditional mere measurement effect, and (c) an additional “mere measurement plus” effect of an open-ended positive solicitation; all effects increased customer spending. Specifically, starting a survey with an open-ended positive solicitation resulted in a 32.88% increase in customer spending relative to a survey with no open-ended positive solicitation. The findings suggest that firms can proactively influence the feedback process. Soliciting open-ended positive feedback can create positively biased memories of an experience; the subsequent expression of those memories in an open-ended feedback format further reinforces them, making them more salient and accessible in guiding future purchase behavior

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals