Abstract
Carbon capture and storage (CCS) is a key technology to mitigate the environmental impact of carbon dioxide (CO
2
) emissions. An understanding of the potential trapping and storage ...mechanisms is required to provide confidence in safe and secure CO
2
geological sequestration
1,2
. Depleted hydrocarbon reservoirs have substantial CO
2
storage potential
1
,
3
, and numerous hydrocarbon reservoirs have undergone CO
2
injection as a means of enhanced oil recovery (CO
2
-EOR), providing an opportunity to evaluate the (bio)geochemical behaviour of injected carbon. Here we present noble gas, stable isotope, clumped isotope and gene-sequencing analyses from a CO
2
-EOR project in the Olla Field (Louisiana, USA). We show that microbial methanogenesis converted as much as 13–19% of the injected CO
2
to methane (CH
4
) and up to an additional 74% of CO
2
was dissolved in the groundwater. We calculate an in situ microbial methanogenesis rate from within a natural system of 73–109 millimoles of CH
4
per cubic metre (standard temperature and pressure) per year for the Olla Field. Similar geochemical trends in both injected and natural CO
2
fields suggest that microbial methanogenesis may be an important subsurface sink of CO
2
globally. For CO
2
sequestration sites within the environmental window for microbial methanogenesis, conversion to CH
4
should be considered in site selection.
The term microgrid is usually reserved for a modest sized, local distributed generation network that will largely operate standalone (i.e., without a grid connection.) The most common power flow ...control method utilized in a standalone microgrid is a technique known as power-frequency droop. This paper introduces the concept of utilizing an arctan function for the power-frequency droop profile. The use of this arctan function improves the small signal stability of the two-inverter microgrid, provides natural frequency bounding, and is flexible in its application. SABER simulations are performed to obtain the operating points about which the system is linearized for the stability analysis. Experimental results obtained from a dSPACE-controlled, low-voltage, two-inverter hardware system are presented to verify the theoretical and simulation results.
Abstract Background context The objective of the North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Lumbar Disc Herniation with Radiculopathy ...is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of lumbar disc herniation with radiculopathy. The guideline is intended to reflect contemporary treatment concepts for symptomatic lumbar disc herniation with radiculopathy as reflected in the highest quality clinical literature available on this subject as of July 2011. The goals of the guideline recommendations are to assist in delivering optimum efficacious treatment and functional recovery from this spinal disorder. Purpose To provide an evidence-based educational tool to assist spine specialists in the diagnosis and treatment of lumbar disc herniation with radiculopathy. Study design Systematic review and evidence-based clinical guideline. Methods This guideline is a product of the Lumbar Disc Herniation with Radiculopathy Work Group of NASS' Evidence-Based Guideline Development Committee. The work group consisted of multidisciplinary spine care specialists trained in the principles of evidence-based analysis. A literature search addressing each question and using a specific search protocol was performed on English-language references found in Medline, Embase (Drugs and Pharmacology), and four additional evidence-based databases to identify articles. The relevant literature was then independently rated using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final recommendations to answer each clinical question were developed via work group discussion, and grades were assigned to the recommendations using standardized grades of recommendation. In the absence of Level I to IV evidence, work group consensus statements have been developed using a modified nominal group technique, and these statements are clearly identified as such in the guideline. Results Twenty-nine clinical questions were formulated and addressed, and the answers are summarized in this article. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence. Conclusions The clinical guideline has been created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with symptomatic lumbar disc herniation with radiculopathy. The entire guideline document, including the evidentiary tables, suggestions for future research, and all the references, is available electronically on the NASS Web site at http://www.spine.org/Pages/PracticePolicy/ClinicalCare/ClinicalGuidlines/Default.aspx and will remain updated on a timely schedule.
•The importance of early phase cost estimation is presented and argued.•Most appropriate literature cost models to the issue are identified and reviewed.•The suitability of literature cost models is ...assessed and discussed.•Relevant cost drivers are identified.•A cost estimation outline is proposed to support assembly cost prediction.
The aim of this research is to support early phase cost estimation for assembly systems design and automation decision. During this phase, various alternatives of assembly systems with different automation levels can be generated. The alternatives generation is performed using available information on product design, assembly sequences, and planned production information. The issue is to assess given alternatives, identify, and opt for the most appropriate one. Several criteria have to be considered in this decision. The economic aspect represents one of the most preponderant, including cost and profitability prediction. The importance and challenges of this complex issue are highlighted in this paper with feedbacks from manufacturers and the literature. The literature in the field is reviewed, presented, and analyzed. For this sake, a selection of cost models is performed covering a wide chronological range, journals, and fields including assembly and manufacturing models. Classification techniques of cost estimation works are presented and exploited in the proposed review. It is used to filter and discuss models suitability for the defined assembly automation decision issue. The most appropriate models are more thoroughly reviewed and discussed. Useful literature costing techniques, features, and relevant cost drivers are also identified. They cover multiple aspects as production information, resources features or performances. Finally, the review findings are illustrated by a cost estimation outline proposal to support early phase cost prediction for assembly systems design and automation decision.
Are aposematic signals honest? A review Summers, K; Speed, M. P; Blount, J. D ...
Journal of evolutionary biology,
September 2015, Letnik:
28, Številka:
9
Journal Article
Recenzirano
Odprti dostop
We explore the relevance of honest signalling theory to the evolution of aposematism. We begin with a general consideration of models of signal stability, with a focus on the Zahavian costly ...signalling framework. Next, we review early models of signalling in the context of aposematism (some that are consistent and some inconsistent with costly honest signalling). We focus on controversies surrounding the idea that aposematic signals are handicaps in a Zahavian framework. Then, we discuss how the alignment of interests between signaller and predator influences the evolution of aposematism, highlight the distinction between qualitative and quantitative honesty and review theory and research relevant to these categories. We also review recent theoretical treatments of the evolution of aposematism that have focused on honest signalling as well as empirical research on a variety of organisms, including invertebrates and frogs. Finally, we discuss future directions for empirical and theoretical research in this area.
Abstract Systemic lupus erythematosus is a common autoimmune disease, with kidney involvement a serious complication associated with poor prognosis. Humoral immune responses constitute the hallmark ...of disease, however T helper cells are required for the generation of autoantibodies, as well as the induction and progression of renal injury. Administration of pristane to genetically intact mice results in the development of hypergammaglobulinaemia with the production of lupus like autoantibodies and proliferative glomerulonephritis, with similarities to human lupus nephritis. TLRs are intricately linked to the development of autoimmunity and are involved in the development of lupus nephritis. We injected wild type, TLR9−/− and TLR4−/− mice with pristane and assessed cellular and humoral autoimmunity and renal injury, 8 months later. TLR9−/− mice demonstrated a predominant decrease in Th1 cytokine production which resulted in decreased anti-RNP antibody levels, while anti-dsDNA levels remained intact. Compared to wild type mice treated with pristane, functional and histological renal injury and glomerular immunoglobulin and complement deposition was decreased in TLR9−/− mice. TLR4−/− mice demonstrated a global decrease in both Th1, IFNγ, and Th17 associated IL-17A and IL-6 cytokine production. Autoantibody levels of anti-dsDNA and anti-RNP were both decreased. Renal injury was attenuated in TLR4−/− mice which demonstrated less glomerular immunoglobulin and complement deposition. These results demonstrate that both TLR9 and TLR4 are required for ‘full-blown’ autoimmunity and organ injury in experimental lupus induced by pristane.
Background Increasing emphasis on family‐centred approaches to services and supports for families of children with disabilities has surfaced the issue of accountability for family outcomes. We ...present a review of literature about the impacts of children with disabilities on families as a backdrop to proposing family quality of life as a concept that encompasses impacts of disability and one that can be used to assess the impact of supports and services on families.
Method We briefly introduce the Beach Center Family Quality of Life Scale, providing information about its factor structure, reliability and convergent validity.
Results The Beach Center Family Quality of Life Scale contains 25 items assessing family ratings of importance and satisfaction with five domains: Family interaction, Parenting, Emotional well‐being, Physical/material well‐being and Disability‐related supports.
Conclusion We present a framework for utilizing a measure of family quality of life as a long‐term outcome in concert with other short‐term measures of service outcomes for families.
Abstract
We augment the heliospheric network of galactic cosmic ray (GCR) monitors using 2012–2017 penetrating radiation measurements from the New Horizons (NH) Pluto Energetic Particle Spectrometer ...Science Investigation (PEPSSI), obtaining intensities of ≳75 MeV particles. The new, predominantly GCR observations provide critical links between the Sun and Voyager 2 and Voyager 1 (V2 and V1), in the heliosheath and local interstellar medium (LISM), respectively. We provide NH, Advanced Composition Explorer (ACE), V2, and V1 GCR observations, using them to track solar cycle variations and short-term Forbush decreases from the Sun to the LISM, and to examine the interaction that results in the surprising, previously reported V1 LISM anisotropy episodes. To investigate these episodes and the hitherto unexplained lagging of associated in situ shock features at V1, propagating disturbances seen at ACE, NH, and V2 were compared to V1. We conclude that the region where LISM magnetic field lines drape around the heliopause is likely critical for communicating solar disturbance signals upstream of the heliosheath to V1. We propose that the anisotropy-causing physical process that suppresses intensities at ∼90° pitch angles relies on GCRs escaping from a single compression in the draping region, not on GCRs trapped between two compressions. We also show that NH suprathermal and energetic particle data from PEPSSI are consistent with the interpretation that traveling shocks and corotating interaction region (CIR) remnants can be distinguished by the existence or lack of Forbush decreases, respectively, because turbulent magnetic fields at local shocks inhibit GCR transport while older CIR structures reaching the outer heliosphere do not.
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