Optimal Investment in the Development of Oil and Gas Field

Let an oil and gas field consists of clusters in each of which an investor can launch at most one project. During the implementation of a particular project, all characteristics are known, including annual production volumes, necessary investment volumes, and profit. The total amount of investments that the investor spends on developing the field during the entire planning period we know. It is required to determine which projects to implement in each cluster so that, within the total amount of investments, the profit for the entire planning period is maximum. The problem under consideration is NP-hard. However, it is solved by dynamic programming with pseudopolynomial time complexity. Nevertheless, in practice, there are additional constraints that do not allow solving the problem with acceptable accuracy at a reasonable time. Such restrictions, in particular, are annual production volumes. In this paper, we considered only the upper constraints that are dictated by the pipeline capacity. For the investment optimization problem with such additional restrictions, we obtain qualitative results, propose an approximate algorithm, and investigate its properties. Based on the results of a numerical experiment, we conclude that the developed algorithm builds a solution close (in terms of the objective function) to the optimal one

Use of a Semi-field System to Evaluate the Efficacy of Topical Repellents under user Conditions Provides a Disease Exposure free Technique Comparable with Field Data.

Before topical repellents can be employed as interventions against arthropod bites, their efficacy must be established. Currently, laboratory or field tests, using human volunteers, are the main methods used for assessing the efficacy of topical repellents. However, laboratory tests are not representative of real life conditions under which repellents are used and field-testing potentially exposes human volunteers to disease. There is, therefore, a need to develop methods to test efficacy of repellents under real life conditions while minimizing volunteer exposure to disease. A lotion-based, 15% N, N-Diethyl-3-methylbenzamide (DEET) repellent and 15% DEET in ethanol were compared to a placebo lotion in a 200 sq m (10 m x 20 m) semi-field system (SFS) against laboratory-reared Anopheles arabiensis mosquitoes and in full field settings against wild malaria vectors and nuisance-biting mosquitoes. The average percentage protection against biting mosquitoes over four hours in the SFS and field setting was determined. A Poisson regression model was then used to determine relative risk of being bitten when wearing either of these repellents compared to the placebo. Average percentage protection of the lotion-based 15% DEET repellent after four hours of mosquito collection was 82.13% (95% CI 75.94-88.82) in the semi-field experiments and 85.10% (95% CI 78.97-91.70) in the field experiments. Average percentage protection of 15% DEET in ethanol after four hours was 71.29% (CI 61.77-82.28) in the semi-field system and 88.24% (84.45-92.20) in the field. Semi-field evaluation results were comparable to full-field evaluations, indicating that such systems could be satisfactorily used in measuring efficacy of topically applied mosquito repellents, thereby avoiding risks of exposure to mosquito-borne pathogens, associated with field testing

Uneven splitting-ratio 1x2 multimode interference splitters based on silicon wire waveguides

Two types of 1x2 multi-mode interference (MMI) splitters with splitting ratios of 85:15 and 72:28 are designed. On the basis of a numerical simulation, an optimal length of the MMI section is obtained. Subsequently, the devices are fabricated and tested. The footprints of the rectangular MMI regions are only 3x18.2 and 3x14.3 (mu m). The minimum excess losses are 1.4 and 1.1 dB. The results of the test on the splitting ratios are consistent with designed values. The devices can be applied in ultra-compact photonic integrated circuits to realize the "tap" function

Profiling of the perturbed metabolomic state of mouse spleen during acute and chronic toxoplasmosis

Background Toxoplasma gondii, a common opportunistic protozoan, is a leading cause of illness and mortality among immunosuppressed individuals and during congenital infections. Current therapeutic strategies for toxoplasmosis are not fully effective at curtailing disease progression in these cases. Given the parasite ability to influence host immunity and metabolism, understanding of the metabolic alterations in the host’s immune organs during T. gondii infection may enhance the understanding of the molecular mechanisms that define the pathophysiology of T. gondii infection. Methods We investigated the global metabolic changes in the spleen of BALB/c mice at early and late stage of infection with T. gondii using LC-MS/MS-based metabolomics. Multivariate data analysis methods, principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA), were used to identify metabolites that are influenced by T. gondii infection. Results Multivariate analyses clearly separated the metabolites of spleen of infected and control mice. A total of 132 differential metabolites were identified, 23 metabolites from acutely infected versus control mice and 109 metabolites from chronically infected versus control mice. Lipids, hormones, lactones, acids, peptides, antibiotics, alkaloids and natural toxins were the most influenced chemical groups. There were 12 shared differential metabolites between acutely infected versus control mice and chronically infected versus control mice, of which 4,4-Dimethyl-5alpha-cholesta-8,14,24-trien-3beta-ol was significantly upregulated and ubiquinone-8 was significantly downregulated. Major perturbed metabolic pathways included primary bile acid biosynthesis, steroid hormone biosynthesis, biotin metabolism, and steroid biosynthesis, with arachidonic acid metabolism being the most significantly impacted pathway. These metabolic changes suggest a multifactorial nature of the immunometabolic responses of mouse spleen to T. gondii infection. Conclusions This study demonstrated that T. gondii infection can cause significant metabolomic alterations in the spleen of infected mice. These findings provide new insights into the molecular mechanisms that underpin the pathogenesis of T. gondii infection

Recombination dynamics of a human Y-chromosomal palindrome:rapid GC-biased gene conversion, multi-kilobase conversion tracts, and rare inversions

The male-specific region of the human Y chromosome (MSY) includes eight large inverted repeats (palindromes) in which arm-to-arm similarity exceeds 99.9%, due to gene conversion activity. Here, we studied one of these palindromes, P6, in order to illuminate the dynamics of the gene conversion process. We genotyped ten paralogous sequence variants (PSVs) within the arms of P6 in 378 Y chromosomes whose evolutionary relationships within the SNP-defined Y phylogeny are known. This allowed the identification of 146 historical gene conversion events involving individual PSVs, occurring at a rate of 2.9-8.4×10(-4) events per generation. A consideration of the nature of nucleotide change and the ancestral state of each PSV showed that the conversion process was significantly biased towards the fixation of G or C nucleotides (GC-biased), and also towards the ancestral state. Determination of haplotypes by long-PCR allowed likely co-conversion of PSVs to be identified, and suggested that conversion tract lengths are large, with a mean of 2068 bp, and a maximum in excess of 9 kb. Despite the frequent formation of recombination intermediates implied by the rapid observed gene conversion activity, resolution via crossover is rare: only three inversions within P6 were detected in the sample. An analysis of chimpanzee and gorilla P6 orthologs showed that the ancestral state bias has existed in all three species, and comparison of human and chimpanzee sequences with the gorilla outgroup confirmed that GC bias of the conversion process has apparently been active in both the human and chimpanzee lineages

Three-Dimensional Graphene Nano-Networks with High Quality and Mass Production Capability via Precursor-Assisted Chemical Vapor Deposition

We report a novel approach to synthesize chemical vapor deposition-grown three-dimensional graphene nano-networks (3D-GNs) that can be mass produced with large-area coverage. Annealing of a PVA/iron precursor under a hydrogen environment, infiltrated into 3D-assembled-colloidal silicas reduces iron ions and generates few-layer graphene by precipitation of carbon on the iron surface. The 3D-GN can be grown on any electronic device-compatible substrate, such as Al2O3, Si, GaN, or Quartz. The conductivity and surface area of a 3D-GN are 52 S/cm and 1,025 m(2)/g, respectively, which are much better than the previously reported values. Furthermore, electrochemical double-layer capacitors based on the 3D-GN have superior supercapacitor performance with a specific capacitance of 245 F/g and 96.5% retention after 6,000 cycles due to the outstanding conductivity and large surface area. The excellent performance of the 3D-GN as an electrode for supercapacitors suggests the great potential of interconnected graphene networks in nano-electronic devices and energy-related materials.open15

Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

The decay channel $\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p})$ is studied using a sample of $1.06\times 10^8$ $\psi^\prime$ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the $p\bar{p}$ invariant mass spectrum. The enhancement can be fit with an $S$-wave Breit-Wigner resonance function with a resulting peak mass of $M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2$ and a narrow width that is $\Gamma<38 {\rm MeV/}c^2$ at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

Both the Caspase CSP-1 and a Caspase-Independent Pathway Promote Programmed Cell Death in Parallel to the Canonical Pathway for Apoptosis in Caenorhabditis elegans

Caspases are cysteine proteases that can drive apoptosis in metazoans and have critical functions in the elimination of cells during development, the maintenance of tissue homeostasis, and responses to cellular damage. Although a growing body of research suggests that programmed cell death can occur in the absence of caspases, mammalian studies of caspase-independent apoptosis are confounded by the existence of at least seven caspase homologs that can function redundantly to promote cell death. Caspase-independent programmed cell death is also thought to occur in the invertebrate nematode Caenorhabditis elegans. The C. elegans genome contains four caspase genes (ced-3, csp-1, csp-2, and csp-3), of which only ced-3 has been demonstrated to promote apoptosis. Here, we show that CSP-1 is a pro-apoptotic caspase that promotes programmed cell death in a subset of cells fated to die during C. elegans embryogenesis. csp-1 is expressed robustly in late pachytene nuclei of the germline and is required maternally for its role in embryonic programmed cell deaths. Unlike CED-3, CSP-1 is not regulated by the APAF-1 homolog CED-4 or the BCL-2 homolog CED-9, revealing that csp-1 functions independently of the canonical genetic pathway for apoptosis. Previously we demonstrated that embryos lacking all four caspases can eliminate cells through an extrusion mechanism and that these cells are apoptotic. Extruded cells differ from cells that normally undergo programmed cell death not only by being extruded but also by not being engulfed by neighboring cells. In this study, we identify in csp-3; csp-1; csp-2 ced-3 quadruple mutants apoptotic cell corpses that fully resemble wild-type cell corpses: these caspase-deficient cell corpses are morphologically apoptotic, are not extruded, and are internalized by engulfing cells. We conclude that both caspase-dependent and caspase-independent pathways promote apoptotic programmed cell death and the phagocytosis of cell corpses in parallel to the canonical apoptosis pathway involving CED-3 activation.Howard Hughes Medical InstituteDamon Runyon Cancer Research FoundationCharles A. King Trus

Observation of CR Anisotropy with ARGO-YBJ

The measurement of the anisotropies of cosmic ray arrival direction provides important informations on the propagation mechanisms and on the identification of their sources. In this paper we report the observation of anisotropy regions at different angular scales. In particular, the observation of a possible anisotropy on scales between $\sim$ 10 $^{\circ}$ and $\sim$ 30 $^{\circ}$ suggests the presence of unknown features of the magnetic fields the charged cosmic rays propagate through, as well as potential contributions of nearby sources to the total flux of cosmic rays. Evidence of new weaker few-degree excesses throughout the sky region $195^{\circ}\leq$ R.A. $\leq 315^{\circ}$ is reported for the first time.Comment: Talk given at 12th TAUP Conference 2011, 5-9 September 2011, Munich, German