729 research outputs found

    Policy making under uncertainty in electric vehicle demand

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    The introduction of electric vehicles (EVs) into the passenger vehicle market has, in recent years, become viewed as a primary solution to the significant carbon dioxide emissions attributed to personal mobility. Moreover, EVs offer a means by which energy diversification and efficiency can be improved compared to the current system. The UK government and European Commission have played an active role in steering the development and market introduction of EVs. However, a great deal of uncertainty remains regarding the effectiveness of these policies and the viability of EV technology in the mainstream automotive market. This paper investigates the prevalence of uncertainty concerning the demand for EVs. This is achieved through the application of a conceptual framework that assesses the locations of uncertainty. UK and EU documents are assessed through a review of the published policy alongside contributions from academia to determine how uncertainty has been reduced. This assessment offers insights to decision makers in this area by evaluating the work done to date through a landscape analysis. Results have identified six different locations of uncertainty covering: consumer, policy, infrastructure, technical, economic and social issues

    The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs

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    The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkey's zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised

    An exploratory policy analysis of electric vehicle sales competition and sensitivity to infrastructure in Europe

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    This research contributes to discussions about policy interventions to stimulate the transition of vehicle technology. Concentrating on passenger cars, an extensive system dynamics based market agent model of powertrain technology transitions within the EU up to 2050 is employed. With a focus on subsidy scenarios for both infrastructure deployment and vehicle purchase, and set within the context of the EU fleet emission regulations, we find that there are important interactions between different powertrain types and with infrastructure provision. For example, strong plug-in electric vehicle (PiEV) policy could inhibit the maturity of hydrogen fuel cell vehicles. Infrastructure provision is important for improving the utility of a PiEV, but we find that in the early market it may have a weaker correlation with uptake than other policy options, until the PiEV stock share is over around 5%. Furthermore, an attempt to install a ratio of much more than one charge point per 10 PiEV may lead to little gains and high costs. PiEV sales are relatively insensitive at target levels over 25 PiEV per charge point. The results of our study can help policymakers to find the right balance and timing of measures targeting the transition towards low carbon alternative vehicles

    Severe leukoencephalopathy with fulminant cerebral edema reflecting immune reconstitution inflammatory syndrome during HIV infection: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Immune reconstitution inflammatory syndrome is a well-known complication in HIV-infected patients after initiation of highly active antiretroviral therapy resulting in rapid CD4<sup>+ </sup>cell count recovery and suppression of viral load. Generally, immune reconstitution inflammatory syndrome is based on opportunistic infections, but rare cases of immune reconstitution inflammatory syndrome inducing demyelinization of the nervous system have also been observed.</p> <p>Case presentation</p> <p>A 37-year-old African woman with HIV infection diagnosed at 13 years of age was admitted to the emergency department after experiencing backache, severe headache, acute aphasia and psychomotor slowing for one week. Nine weeks earlier, highly active antiretroviral therapy in this patient had been changed because of loss of efficacy, and a rapid increase in CD4<sup>+ </sup>cell count and decrease of HIV viral load were observed. Magnetic resonance imaging of the brain showed extensive white matter lesions, and analysis of cerebrospinal fluid revealed an immunoreactive syndrome. Intensive investigations detected no opportunistic infections. A salvage therapy, including osmotherapy, corticosteroids and treatment of epileptic seizures, was performed, but the patient died from brainstem herniation 48 hours after admission. Neuropathologic examination of the brain revealed diffuse swelling, leptomeningeal infiltration by CD8 cells and enhancement of perivascular spaces by CD8+ cells.</p> <p>Conclusion</p> <p>Immune reconstitution inflammatory syndrome in this form seems to represent a severe autoimmunologic disease of the brain with specific histopathologic findings. This form of immune reconstitution inflammatory syndrome did not respond to therapy, and extremely rapid deterioration led to death within two days. Immune reconstitution inflammatory syndrome may also occur as severe leukoencephalopathy with fulminant cerebral edema during HIV infection with rapid immune reconstitution.</p

    Hierarchy measure for complex networks

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    Nature, technology and society are full of complexity arising from the intricate web of the interactions among the units of the related systems (e.g., proteins, computers, people). Consequently, one of the most successful recent approaches to capturing the fundamental features of the structure and dynamics of complex systems has been the investigation of the networks associated with the above units (nodes) together with their relations (edges). Most complex systems have an inherently hierarchical organization and, correspondingly, the networks behind them also exhibit hierarchical features. Indeed, several papers have been devoted to describing this essential aspect of networks, however, without resulting in a widely accepted, converging concept concerning the quantitative characterization of the level of their hierarchy. Here we develop an approach and propose a quantity (measure) which is simple enough to be widely applicable, reveals a number of universal features of the organization of real-world networks and, as we demonstrate, is capable of capturing the essential features of the structure and the degree of hierarchy in a complex network. The measure we introduce is based on a generalization of the m-reach centrality, which we first extend to directed/partially directed graphs. Then, we define the global reaching centrality (GRC), which is the difference between the maximum and the average value of the generalized reach centralities over the network. We investigate the behavior of the GRC considering both a synthetic model with an adjustable level of hierarchy and real networks. Results for real networks show that our hierarchy measure is related to the controllability of the given system. We also propose a visualization procedure for large complex networks that can be used to obtain an overall qualitative picture about the nature of their hierarchical structure.Comment: 29 pages, 9 figures, 4 table

    The plant WEE1 kinase is involved in checkpoint control activation in nematode-induced galls

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    Galls induced by plant‐parasitic nematodes involve a hyperactivation of the plant mitotic and endocycle machinery for their profit. Dedifferentiation of host root cells includes drastic cellular and molecular readjustments. In such background, potential DNA damage in the genome of gall cells is eminent. We questioned if DNA damage checkpoints activation followed by DNA repair occurred, or was eventually circumvented, in nematode‐induced galls. Galls display transcriptional activation of the DNA damage checkpoint kinase WEE1, correlated with its protein localization in the nuclei. The promoter of the stress marker gene SMR7 was evaluated under the WEE1‐knockout background. Drugs inducing DNA damage and a marker for DNA repair, PARP1 were used to understand mechanisms that might cope with DNA damage in galls. Our functional study revealed that gall cells lacking WEE1 conceivably entered mitosis prematurely disturbing the cell cycle despite the loss of genome integrity. The disrupted nuclei phenotype in giant cells hinted to the accumulation of mitotic defects. As well, WEE1‐knockout in Arabidopsis and downregulation in tomato repressed infection and reproduction of root‐knot nematodes. Together with data on DNA damaging drugs, we suggest a conserved function for WEE1 controlling a G1/S cell cycle arrest in response to replication defect in galls

    Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study

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    Introduction Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation. Methods Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mechanically ventilated and required norepinephrine to maintain a mean arterial pressure (MAP) of 65 mmHg. We measured systemic hemodynamics, oxygen transport and consumption (DO2 and VO2), lactate, albumin-corrected anion gap, and gastric intramucosal-arterial PCO2 difference (Delta PCO2). Sublingual microcirculation was evaluated by sidestream darkfield (SDF) imaging. After basal measurements at a MAP of 65 mmHg, norepinephrine was titrated to reach a MAP of 75 mmHg, and then to 85 mmHg. Data were analyzed using repeated measurements ANOVA and Dunnett test. Linear trends between the different variables and increasing levels of MAP were calculated. Results Increasing doses of norepinephrine reached the target values of MAP. The cardiac index, pulmonary pressures, systemic vascular resistance, and left and right ventricular stroke work indexes increased as norepinephrine infusion was augmented. Heart rate, DO2 and VO2, lactate, albumin-corrected anion gap, and Delta PCO2 remained unchanged. There were no changes in sublingual capillary microvascular flow index (2.1 +/- 0.7, 2.2 +/- 0.7, 2.0 +/- 0.8) and the percent of perfused capillaries (72 +/- 26, 71 +/- 27, 67 +/- 32%) for MAP values of 65, 75, and 85 mmHg, respectively. There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm(2), respectively, ANOVA P = 0.09, linear trend P = 0.045). In addition, the changes of perfused capillary density at increasing MAP were inversely correlated with the basal perfused capillary density (R-2 = 0.95, P < 0.0001). Conclusions Patients with septic shock showed severe sublingual microcirculatory alterations that failed to improve with the increases in MAP with norepinephrine. Nevertheless, there was a considerable interindividual variation. Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patient

    Exploiting tumour addiction with a serine and glycine-free diet.

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    Understanding cancer metabolism is key to unveil the Achilles’ heel of cancer cells and provide novel therapeutic interventions for patients. While the rerouting of metabolic pathways during development1 or cancer transformation and progression2, 3, 4 has been extensively characterised, the exact dynamic of these events, their distribution and frequency in the different tumour types, and the correlation with genetic background remain largely unknown. In a recent article published in Nature, Karen Vousden’s team assesses the effect of serine and glycine dietary restriction in autochthonous mouse tumour models driven by different oncogenes (Maddocks et al, 2017)5, leading to potential area of therapeutic intervention

    Association between genetic variants in key vitamin‐D‐pathway genes and external apical root resorption linked to orthodontic treatment

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    This study evaluated the association between single-nucleotide polymorphisms (SNPs) in vitamin-D-related genes and the amount of external apical root resorption linked to orthodontic treatment. One hundred and forty-three individuals were assessed. The amount of external apical root resorption of upper central incisors (EARRinc) and lower first molars (EARRmol) were evaluated in radiographs. Seven SNPs were genotyped across four genes including the vitamin D receptor [VDR], group-specific component [GC], cytochrome P450 family 27 subfamily B member 1 [CYP27B1], and cytochrome P450 family 24 subfamily A member 1 [CYP24A1]. Linear regressions were implemented to determine allele-effects on external apical root resorption. Individuals carrying the AA genotype in VDR rs2228570 had a 21% higher EARRmol than those having AG and GG genotypes (95% CI: 1.03,1.40). EARRmol in heterozygous rs2228570, was 12% lower than for homozygotes (95%CI: 0.78,0.99). Participants with the CCG haplotype (rs1544410-rs7975232-rs731236) in VDR had an EARRmol 16% lower than those who did not carry this haplotype. Regarding CYP27B1 rs4646536, EARRinc in participants who had at least one G allele was 42% lower than for homozygotes AA (95%CI: 0.37,0.93). Although these results did not remain significant after multiple testing adjustment, potential associations may still be suggested. Further replication studies are needed to confirm or refute these findings
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