Coupling climate and economic models in a cost-benefit framework: a convex optimization approach

In this paper we present a general method, based on a convex optimisation technique, that facilitates the coupling of climate and economic models in a cost-benefit framework. As a demonstration of the method, we couple an economic growth model à la Ramsey adapted from DICE-99 with an efficient intermediate complexity climate model, C-GOLDSTEIN, which has highly simplified physics, but fully 3-D ocean dynamics. As in DICE-99 we assume that an economic cost is associated with global temperature change: this change is obtained from the climate model which is driven by the GHG concentrations computed from the economic growth path. The work extends a previous paper in which these models were coupled in cost-effectiveness mode. Here we consider the more intricate cost-benefit coupling in which the climate impact is not fixed a priori. We implement the coupled model using an oracle-based optimisation technique. Each model is contained in an oracle which supplies model output and information on its sensitivity to a master program. The algorithm Proximal-ACCPM guarantees the convergence of the procedure under sufficient convexity assumptions. Our results demonstrate the possibility of a consistent, cost-benefit, climate-damage optimisation analysis with a 3-D climate model

Range extensions along western Atlantic for Epialtidae crabs (Brachyura, Majoidea) genera Acanthonyx Latreille, 1828 and Epialtus H. Milne Edwards, 1834

The present study provided information extending the known geographical distribution of three species of majoid crabs, the epialtids Acanthonyx dissimulatus Coelho, 1993, Epialtus bituberculatus H. Milne Edwards, 1834, and E. brasiliensis Dana, 1852. Specimens of both genera from different carcinological collections were studied by comparing morphological characters. We provide new data that extends the geographical distributions of E. bituberculatus to the coast of the states of Paraná and Santa Catarina (Brazil), and offer new records from Belize and Costa Rica. Epialtus brasiliensis is recorded for the first time in the state of Rio Grande do Sul (Brazil), and A. dissimulatus is reported from Quintana Roo, Mexico. The distribution of A. dissimulatus, previously known as endemic to Brazil, has a gap between the states of Espírito Santo and Rio de Janeiro. However, this restricted southern distribution is herein amplified by the Mexican specimens

Virus infection and grazing exert counteracting influences on survivorship of native bunchgrass seedlings competing with invasive exotics

1.  Invasive annual grasses introduced by European settlers have largely displaced native grassland vegetation in California and now form dense stands that constrain the establishment of native perennial bunchgrass seedlings. Bunchgrass seedlings face additional pressures from both livestock grazing and barley and cereal yellow dwarf viruses (B/CYDVs), which infect both young and established grasses throughout the state. 2.  Previous work suggested that B/CYDVs could mediate apparent competition between invasive exotic grasses and native bunchgrasses in California. 3.  To investigate the potential significance of virus-mediated mortality for early survivorship of bunchgrass seedlings, we compared the separate and combined effects of virus infection, competition and simulated grazing in a field experiment. We infected two species of young bunchgrasses that show different sensitivity to B/CYDV infection, subjected them to competition with three different densities of exotic annuals crossed with two clipping treatments, and monitored their growth and first-year survivorship. 4.  Although virus infection alone did not reduce first-year survivorship, it halved the survivorship of bunchgrasses competing with exotics. Within an environment in which competition strongly reduces seedling survivorship (as in natural grasslands), virus infection therefore has the power to cause additional seedling mortality and alter patterns of establishment. 5.  Surprisingly, clipping did not reduce bunchgrass survivorship further, but rather doubled it and disproportionately increased survivorship of infected bunchgrasses. 6.  Together with previous work, these findings show that B/CYDVs can be potentially powerful elements influencing species interactions in natural grasslands. 7.  More generally, our findings demonstrate the potential significance of multitrophic interactions in virus ecology. Although sometimes treated collectively as plant ‘predators’, viruses and herbivores may exert influences that are distinctly different, even counteracting

Measurement of Natural Widths of Sigma-c-0 and Sigma-c-++ Baryons

In this paper we present a measurement of the natural widths of $\Sigma_c^0$ and $\Sigma_c^{++}$. Using data from the FOCUS experiment, we find $\Gamma(\Sigma_c^0) = 1.55 +0.41/-0.37 \pm 0.38$ MeV/c^2 and $\Gamma(\Sigma_c^0) = 2.05 +0.41/-0.38 \pm 0.38$ MeV/c^2. The first errors are statistical, the second systematic. These results are obtained with a sample of 913 $\Sigma_c^0 \to \Lambda_c^+ \pi^-$ decays and 1110 $\Sigma_c^++ \to \Lambda_c^+ \pi^+$ decays. These results are compared with recent theoretical predictions. PACS numbers: 14.20.Lq 13.30EgComment: Submitted to Physics Letters

The performance of the jet trigger for the ATLAS detector during 2011 data taking

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction

Movement-generated afference paired with transcranial magnetic stimulation: An associative stimulation paradigm

Background A peripheral nerve stimulus can enhance or suppress the evoked response to transcranial magnetic stimulation (TMS) depending on the latency of the preceding peripheral nerve stimulation (PNS) pulse. Similarly, somatosensory afference from the passively moving limb can transiently alter corticomotor excitability, in a phase-dependent manner. The repeated association of PNS with TMS is known to modulate corticomotor excitability; however, it is unknown whether repeated passive-movement associative stimulation (MAS) has similar effects. Methods In a proof-of-principle study, using a cross-over design, seven healthy subjects received in separate sessions: (1) TMS (120% of the resting motor threshold-RMT, optimal site for Flexor Carpi Radialis) with muscle at rest; (2) TMS paired with cyclic passive movement during extension cyclic passive movement (400 pairs, 1 Hz), with the intervention order randomly assigned. Normality was tested using the Kolmogorov-Smirnov test, then compared to pre-intervention baseline using repeated measures ANOVA with a Dunnet multiple comparisons test. Results MAS led to a progressive and significant decrease in the motor evoked potential (MEP) amplitude over the intervention (R2 = 0.6665, P < 0.0001), which was not evident with TMS alone (R2 = 0.0068, P = 0.641). Post-intervention excitability reduction, only present with MAS intervention, remained for 20min (0-10min = 68.2 ± 4.9%, P < 0.05; 10-20min = 73.3 ± 9.7%, P < 0.05). Conclusion The association of somatosensory afference from the moving limb with TMS over primary motor cortex in healthy subjects can be used to modulate corticomotor excitability, and may have therapeutic implications

Reduced corticomotor excitability with cyclic passive movement: A study using Transcranial Magnetic Stimulation

Human voluntary movement involves the integration of kinaesthetic information with efferent motor activity during the planning and execution stages of movement. While much is known of the inhibitory and excitatory effects resulting from activation of specific kinaesthetic sensory receptors, in the present study we employed cyclic passive movement of the index finger in order to activate a range of kinaesthetic receptors in a manner that was intended to correspond to how these receptors might be active during a comparable voluntary movement. We intended to identify how this passive movement protocol might affect the excitability of the corticomotor pathway. During 1 Hz cyclic passive movement of the index finger there was an ∼60% reduction in the amplitude of the motor evoked response from the first dorsal interosseous muscle. The results of the present study demonstrate that passive movement can have a profound effect on the excitability of the corticomotor pathway