228 research outputs found
Second best toll and capacity optimisation in network: solution algorithm and policy implications
This paper looks at the first and second-best jointly optimal toll and road capacity investment problems from both policy and technical oriented perspectives. On the technical side, the paper investigates the applicability of the constraint cutting algorithm for solving the second-best problem under elastic demand which is formulated as a bilevel programming problem. The approach is shown to perform well despite several problems encountered by our previous work in Shepherd and Sumalee (2004). The paper then applies the algorithm to a small sized network to investigate the policy implications of the first and second-best cases. This policy analysis demonstrates that the joint first best structure is to invest in the most direct routes while reducing capacities elsewhere. Whilst unrealistic this acts as a useful benchmark. The results also show that certain second best policies can achieve a high proportion of the first best benefits while in general generating a revenue surplus. We also show that unless costs of capacity are known to be low then second best tolls will be affected and so should be analysed in conjunction with investments in the network
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BIG regulates dynamic adjustment of circadian period in Arabidopsis thaliana
Circadian clocks drive rhythms with a period near 24 h, though the molecular basis of the regulation of circadian period is little understood. We have demonstrated previously that metabolites affect the free-running period of the circadian oscillator of Arabidopsis thaliana, with endogenous sugars acting as an accelerator and exogenous nicotinamide acting as a brake. Changes in circadian oscillator period are thought to adjust the timing of biological activities through the process of entrainment, in which the circadian oscillator becomes synchronised to rhythmic signals such as light and dark cycles, and changes in internal metabolism. To identify molecular components associated with the dynamic adjustment of circadian period we performed a forward genetic screen. We identified mutants that were either period insensitive to nicotinamide (sin) or period oversensitive to nicotinamide (son). We mapped son1 to BIG, a gene of unknown molecular function that has previously been reported to have a role in light signalling. We found that son1 has an early entrained phase suggesting that the dynamic alteration of circadian period contributes to the correct timing of biological events. Our data provide an insight in to how dynamic period adjustment of circadian oscillators contributes to establishing a correct phase relationship with the environment and identifies that BIG is involved in this process
Symptoms and quality of life in late stage Parkinson syndromes: a longitudinal community study of predictive factors
BACKGROUND
Palliative care is increasingly offered earlier in the cancer trajectory but rarely in Idiopathic Parkinson's Disease(IPD), Progressive Supranuclear Palsy(PSP) or Multiple System Atrophy(MSA). There is little longitudinal data of people with late stage disease to understand levels of need. We aimed to determine how symptoms and quality of life of these patients change over time; and what demographic and clinical factors predicted changes.
METHODS
We recruited 82 patients into a longitudinal study, consenting patients with a diagnosis of IPD, MSA or PSP, stages 3-5 Hoehn and Yahr(H&Y). At baseline and then on up to 3 occasions over one year, we collected self-reported demographic, clinical, symptom, palliative and quality of life data, using Parkinson's specific and generic validated scales, including the Palliative care Outcome Scale (POS). We tested for predictors using multivariable analysis, adjusting for confounders.
FINDINGS
Over two thirds of patients had severe disability, over one third being wheelchair-bound/bedridden. Symptoms were highly prevalent in all conditions - mean (SD) of 10.6(4.0) symptoms. More than 50% of the MSA and PSP patients died over the year. Over the year, half of the patients showed either an upward (worsening, 24/60) or fluctuant (8/60) trajectory for POS and symptoms. The strongest predictors of higher levels of symptoms at the end of follow-up were initial scores on POS (AOR 1.30; 95%CI:1.05-1.60) and being male (AOR 5.18; 95% CI 1.17 to 22.92), both were more predictive than initial H&Y scores.
INTERPRETATION
The findings point to profound and complex mix of non-motor and motor symptoms in patients with late stage IPD, MSA and PSP. Symptoms are not resolved and half of the patients deteriorate. Palliative problems are predictive of future symptoms, suggesting that an early palliative assessment might help screen for those in need of earlier intervention
A 6.5-kb intergenic structural variation enhances P450-mediated resistance to pyrethroids in malaria vectors lowering bed net efficacy
Elucidating the complex evolutionary armory that mosquitoes deploy against insecticides is crucial to maintain the effectiveness of insecticide‐based interventions. Here, we deciphered the role of a 6.5‐kb structural variation (SV) in driving cytochrome P450‐mediated pyrethroid resistance in the malaria vector, Anopheles funestus. Whole‐genome pooled sequencing detected an intergenic 6.5‐kb SV between duplicated CYP6P9a/b P450s in pyrethroid‐resistant mosquitoes through a translocation event. Promoter analysis revealed a 17.5‐fold higher activity (p < .0001) for the SV− carrying fragment than the SV− free one. Quantitative real‐time PCR expression profiling of CYP6P9a/b for each SV genotype supported its role as an enhancer because SV+/SV+ homozygote mosquitoes had a significantly greater expression for both genes than heterozygotes SV+/SV− (1.7‐ to 2‐fold) and homozygotes SV−/SV− (4‐to 5‐fold). Designing a PCR assay revealed a strong association between this SV and pyrethroid resistance (SV+/SV+ vs. SV−/SV−; odds ratio [OR] = 2,079.4, p < .001). The 6.5‐kb SV is present at high frequency in southern Africa (80%–100%) but absent in East/Central/West Africa. Experimental hut trials revealed that homozygote SV mosquitoes had a significantly greater chance to survive exposure to pyrethroid‐treated nets (OR 27.7; p < .0001) and to blood feed than susceptible mosquitoes. Furthermore, mosquitoes homozygote‐resistant at the three loci (SV+/CYP6P9a_R/CYP6P9b_R) exhibited a higher resistance level, leading to a far superior ability to survive exposure to nets than those homozygotes susceptible at the three loci, revealing a strong additive effect. This study highlights the important role of structural variations in the development of insecticide resistance in malaria vectors and their detrimental impact on the effectiveness of pyrethroid‐based nets
Cardiac magnetic resonance imaging in Alström syndrome
<p>Abstract</p> <p>Background</p> <p>A case series of the cardiac magnetic resonance imaging findings in seven adult Alström patients.</p> <p>Methods</p> <p>Seven patients from the National Specialist Commissioning Group Centre for Alström Disease, Torbay, England, UK, completed the cardiac magnetic resonance imaging protocol to assess cardiac structure and function in Alström cardiomyopathy.</p> <p>Results</p> <p>All patients had some degree of left and right ventricular dysfunction. Patchy mid wall gadolinium delayed enhancement was demonstrated, suggesting an underlying fibrotic process. Some degree of cardiomyopathy was universal. No evidence of myocardial infarction or fatty infiltration was demonstrated, but coronary artery disease cannot be completely excluded. Repeat scanning after 18 months in one subject showed progression of fibrosis and decreased left ventricular function.</p> <p>Conclusion</p> <p>Adult Alström cardiomyopathy appears to be a fibrotic process causing impairment of both ventricles. Serial cardiac magnetic resonance scanning has helped clarify the underlying disease progression and responses to treatment. Confirmation of significant mutations in the <it>ALMS1 </it>gene should lead to advice to screen the subject for cardiomyopathy, and metabolic disorders.</p
A Pair of Dopamine Neurons Target the D1-Like Dopamine Receptor DopR in the Central Complex to Promote Ethanol-Stimulated Locomotion in Drosophila
Dopamine is a mediator of the stimulant properties of drugs of abuse, including ethanol, in mammals and in the fruit fly Drosophila. The neural substrates for the stimulant actions of ethanol in flies are not known. We show that a subset of dopamine neurons and their targets, through the action of the D1-like dopamine receptor DopR, promote locomotor activation in response to acute ethanol exposure. A bilateral pair of dopaminergic neurons in the fly brain mediates the enhanced locomotor activity induced by ethanol exposure, and promotes locomotion when directly activated. These neurons project to the central complex ellipsoid body, a structure implicated in regulating motor behaviors. Ellipsoid body neurons are required for ethanol-induced locomotor activity and they express DopR. Elimination of DopR blunts the locomotor activating effects of ethanol, and this behavior can be restored by selective expression of DopR in the ellipsoid body. These data tie the activity of defined dopamine neurons to D1-like DopR-expressing neurons to form a neural circuit that governs acute responding to ethanol
Genetic Isolation between the Western and Eastern Pacific Populations of Pronghorn Spiny Lobster Panulirus penicillatus
The pronghorn spiny lobster, Panulirus penicillatus, is a circumtropical species which has the widest global distribution among all the species of spiny lobster, ranging throughout the entire Indo-Pacific region. Partial nucleotide sequences of mitochondrial DNA COI (1,142–1,207 bp) and 16S rDNA (535–546 bp) regions were determined for adult and phyllosoma larval samples collected from the Eastern Pacific (EP)(Galápagos Islands and its adjacent water), Central Pacific (CP)(Hawaii and Tuamotu) and the Western Pacific (WP)(Japan, Indonesia, Fiji, New Caledonia and Australia). Phylogenetic analyses revealed two distinct large clades corresponding to the geographic origin of samples (EP and CP+WP). No haplotype was shared between the two regional samples, and average nucleotide sequence divergence (Kimura's two parameter distance) between EP and CP+WP samples was 3.8±0.5% for COI and 1.0±0.4% for 16S rDNA, both of which were much larger than those within samples. The present results indicate that the Pacific population of the pronghorn spiny lobster is subdivided into two distinct populations (Eastern Pacific and Central to Western Pacific), with no gene flow between them. Although the pronghorn spiny lobster have long-lived teleplanic larvae, the vast expanse of Pacific Ocean with no islands and no shallow substrate which is known as the East Pacific Barrier appears to have isolated these two populations for a long time (c.a. 1MY)
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