Reduction of nitric oxide emissions from a combustor

A turbojet combustor and method for controlling nitric oxide emissions by employing successive combustion zones is described. After combustion of an initial portion of the fuel in a primary combustion zone, the combustion products of the primary zone are combined with the remaining portion of fuel and additional plenum air and burned in a secondary combustion zone under conditions that result in low nitric oxide emissions. Low nitric oxide emissions are achieved by a novel turbojet combustor arrangement which provides flame stability by allowing stable combustion to be accompanied by low nitric oxide emissions resulting from controlled fuel-lean combustion (ignited by the emission products from the primary zone) in a secondary combustion zone at a lower combustion temperature resulting in low emission of nitric oxide

A practical explication of the knowledge rule of informative speech acts

This paper defends the knowledge rule of informative speech acts. It is argued that Edward Craig's insightful practical explication of the concept of knowledge can be extended to motivate the knowledge rule. A number of problem cases for the knowledge rule are addressed and accommodated

Genetic Drift Dominates Genome-Wide Regulatory Evolution Following an Ancient Whole-Genome Duplication in Atlantic Salmon

Whole-genome duplications (WGD) have been considered as springboards that potentiate lineage diversification through increasing functional redundancy. Divergence in gene regulatory elements is a central mechanism for evolutionary diversification, yet the patterns and processes governing regulatory divergence following events that lead to massive functional redundancy, such as WGD, remain largely unknown. We studied the patterns of divergence and strength of natural selection on regulatory elements in the Atlantic salmon (Salmo salar) genome, which has undergone WGD 100–80 Ma. Using ChIPmentation, we first show that H3K27ac, a histone modification typical to enhancers and promoters, is associated with genic regions, tissue-specific transcription factor binding motifs, and with gene transcription levels in immature testes. Divergence in transcription between duplicated genes from WGD (ohnologs) correlated with difference in the number of proximal regulatory elements, but not with promoter elements, suggesting that functional divergence between ohnologs after WGD is mainly driven by enhancers. By comparing H3K27ac regions between duplicated genome blocks, we further show that a longer polyploid state post-WGD has constrained regulatory divergence. Patterns of genetic diversity across natural populations inferred from resequencing indicate that recent evolutionary pressures on H3K27ac regions are dominated by largely neutral evolution. In sum, our results suggest that post-WGD functional redundancy in regulatory elements continues to have an impact on the evolution of the salmon genome, promoting largely neutral evolution of regulatory elements despite their association with transcription levels. These results highlight a case where genome-wide regulatory evolution following an ancient WGD is dominated by genetic drift.Peer reviewe

A Phase III Randomized Trial of Gemcitabine–Oxaliplatin versus Carboplatin–Paclitaxel as First-Line Therapy in Patients with Advanced Non-small Cell Lung Cancer

Purpose:This phase III study compared the efficacy and tolerability of gemcitabine and oxaliplatin (GEMOX) with paclitaxel and carboplatin (PCb) in chemotherapy-naive patients with stage IIIB/IV non-small cell lung cancer.Patients and Methods:Patients aged 18 years or older were randomized to PCb (paclitaxel 225 mg/m2 followed by carboplatin area under the curve = 6 on day 1 every 3 weeks) or GEMOX (gemcitabine 1,000 mg/m2 on days 1 and 8 followed by oxaliplatin 130 mg/m2 on day 1 every 3 weeks) for up to six cycles. The primary end point was progression-free survival (PFS), with tumor response rate, overall survival (OS), and quality of life as secondary end points.Results:The study was terminated after 383 patients had been randomized (371 received treatment) as the incidence of adverse events had exceeded the protocol-specified safety threshold (≥20% in either arm). No formal statistical comparisons were conducted. Median PFS was 4.44 months and 4.67 months in the GEMOX and PCb groups, respectively. Objective response rates (complete or partial) were 15.2% and 22.4% in the GEMOX and PCb arms, respectively. Median OS was 9.90 months (GEMOX) and 9.24 months (PCb); post hoc analyses showed median OS in patients aged 70 years or older to be similar to those younger than 70 years. PFS was similar in both groups of patients with adenocarcinoma histology, although OS favored the GEMOX group. Quality of life was improved from baseline in both groups. Toxicity profiles were comparable between the groups.Conclusion:PFS, OS, and objective response rates with GEMOX were similar to PCb. Nevertheless, toxicities limit the adoption of this regimen for routine use in advanced non-small cell lung cancer

Sub-kilohertz excitation lasers for quantum information processing with Rydberg atoms

Quantum information processing using atomic qubits requires narrow linewidth lasers with long-term stability for high fidelity coherent manipulation of Rydberg states. In this paper, we report on the construction and characterization of three continuous-wave (CW) narrow linewidth lasers stabilized simultaneously to an ultra- high finesse Fabry-Perot cavity made of ultra-low expansion (ULE) glass, with a tunable offset-lock frequency. One laser operates at 852 nm while the two locked lasers at 1018 nm are frequency doubled to 509 nm for excitation of 133Cs atoms to Rydberg states. The optical beatnote at 509 nm is measured to be 260(5) Hz. We present measurements of the offset between the atomic and cavity resonant frequencies using electromagnetically induced transparency (EIT) for high-resolution spectroscopy on a cold atom cloud. The long-term stability is determined from repeated spectra over a period of 20 days yielding a linear frequency drift of ∼ 1 Hz/s

Nutrient supply from fishes facilitates macroalgae and suppresses corals in a Caribbean coral reef ecosystem

On coral reefs, fishes can facilitate coral growth via nutrient excretion; however, as coral abundance declines, these nutrients may help facilitate increases in macroalgae. By combining surveys of reef communities with bioenergetics modeling, we showed that fish excretion supplied 25 times more nitrogen to forereefs in the Florida Keys, USA, than all other biotic and abiotic sources combined. One apparent result was a positive relationship between fish excretion and macroalgal cover on these reefs. Herbivore biomass also showed a negative relationship with macroalgal cover, suggesting strong interactions of top-down and bottom-up forcing. Nutrient supply by fishes also showed a negative correlation with juvenile coral density, likely mediated by competition between macroalgae and corals, suggesting that fish excretion may hinder coral recovery following large-scale coral loss. Thus, the impact of nutrient supply by fishes may be context-dependent and reinforce either coral-dominant or coral-depauperate reef communities depending on initial community states

Regulatory Architecture of Gene Expression Variation in the Threespine Stickleback Gasterosteus aculeatus

Much adaptive evolutionary change is underlain by mutational variation in regions of the genome that regulate gene expression rather than in the coding regions of the genes themselves. An understanding of the role of gene expression variation in facilitating local adaptation will be aided by an understanding of underlying regulatory networks. Here, we characterize the genetic architecture of gene expression variation in the threespine stickleback (Gasterosteus aculeatus), an important model in the study of adaptive evolution. We collected transcriptomic and genomic data from 60 half-sib families using an expression microarray and genotyping-by-sequencing, and located expression quantitative trait loci (eQTL) underlying the variation in gene expression in liver tissue using an interval mapping approach. We identified eQTL for several thousand expression traits. Expression was influenced by polymorphism in both cis- and trans-regulatory regions. Transe-QTL clustered into hotspots. We did not identify master transcriptional regulators in hotspot locations: rather, the presence of hotspots may be driven by complex interactions between multiple transcription factors. One observed hotspot colocated with a QTL recently found to underlie salinity tolerance in the threespine stickleback. However, most other observed hotspots did not colocate with regions of the genome known to be involved in adaptive divergence between marine and freshwater habitats.Peer reviewe

High-Velocity Line Forming Regions in the Type Ia Supernova 2009ig

We report measurements and analysis of high-velocity (> 20,000 km/s) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between -14d and +13d with respect to the time of maximum B-band luminosity. We identify lines of Si II, Si III, S II, Ca II and Fe II that produce both high-velocity (HVF) and photospheric-velocity (PVF) absorption features. SN 2009ig is unusual for the large number of lines with detectable HVF in the spectra, but the light-curve parameters correspond to a slightly overluminous but unexceptional SN Ia (M_B = -19.46 mag and Delta_m15 (B) = 0.90 mag). Similarly, the Si II lambda_6355 velocity at the time of B-max is greater than "normal" for a SN Ia, but it is not extreme (v_Si = 13,400 km/s). The -14d and -13d spectra clearly resolve HVF from Si II lambda_6355 as separate absorptions from a detached line forming region. At these very early phases, detached HVF are prevalent in all lines. From -12d to -6d, HVF and PVF are detected simultaneously, and the two line forming regions maintain a constant separation of about 8,000 km/s. After -6d all absorption features are PVF. The observations of SN 2009ig provide a complete picture of the transition from HVF to PVF. Most SN Ia show evidence for HVF from multiple lines in spectra obtained before -10d, and we compare the spectra of SN 2009ig to observations of other SN. We show that each of the unusual line profiles for Si II lambda_6355 found in early-time spectra of SN Ia correlate to a specific phase in a common development sequence from HVF to PVF.Comment: 19 pages, 11figures, 4 tables, submitted to Ap

CIRPASS: a NIR integral field and multi-object spectrograph

We describe CIRPASS which is currently being completed at the Institute of Astronomy in Cambridge. The optical design is presented and contrasted with more conventional software- suppression designs. The limiting magnitudes on Gemini are expected to be J 22.6 and H 21.7 in a 3 hour exposure