The role of model dynamics in ensemble Kalman filter performance for chaotic systems

The ensemble Kalman filter (EnKF) is susceptible to losing track of observations, or ‘diverging’, when applied to large chaotic systems such as atmospheric and ocean models. Past studies have demonstrated the adverse impact of sampling error during the filter’s update step. We examine how system dynamics affect EnKF performance, and whether the absence of certain dynamic features in the ensemble may lead to divergence. The EnKF is applied to a simple chaotic model, and ensembles are checked against singular vectors of the tangent linear model, corresponding to short-term growth and Lyapunov vectors, corresponding to long-term growth. Results show that the ensemble strongly aligns itself with the subspace spanned by unstable Lyapunov vectors. Furthermore, the filter avoids divergence only if the full linearized long-term unstable subspace is spanned. However, short-term dynamics also become important as nonlinearity in the system increases. Non-linear movement prevents errors in the long-term stable subspace from decaying indefinitely. If these errors then undergo linear intermittent growth, a small ensemble may fail to properly represent all important modes, causing filter divergence. A combination of long and short-term growth dynamics are thus critical to EnKF performance. These findings can help in developing practical robust filters based on model dynamics.National Science Foundation (U.S.) (CMF Program Grant 0530851)National Science Foundation (U.S.) (DDAS Program Grant 0540259)National Science Foundation (U.S.) (ITR/AP Program Grant 0121182

Groundwater analysis for unconfined and clayey layer by using response surface methodology

Groundwater as a source of water stored in aquifers plays an important role in domestic use. However, excessive and uncontrolled water pump activities have side effects such as soil deposition and groundwater reduction. Therefore, Response Surface Methodology (RSM) is an alternative method to optimize the time and quantity of groundwater pumps based on other wells water level changes. The analysis using Design Expert version 10 involves changing the water level at the main wells R1 and R5 with the monitoring of other wells at R2, R3, and R4 within 245 minutes with 48 samples. Based on 4 hours of pump test in different wells, it shows that groundwater production rates indirectly affect pump power factor, water level change, wells location, pump time, and infiltration of soil. R1 (1 hp) has a groundwater rate of 28.65 m3/day, while R5 (2 hp) with 103.63 m3/day. The selection of ANOVA Design-Expert model suitable for R1.R2, R3, R4 and R5 has been evaluated and shows that optimum time is 116.24 minutes (1 hour 55 minutes) for case 1 and 117.48 minutes (1-hour 57 minute) for case 2. In conclusion, this study provides best and suitable pumping time towards the water balance of groundwater. Hence, the reaction from environment and the influences of other factors play an important role in ensuring the continuous water supplement of groundwater

Phytoremediation efficiencies of Spirodela polyrhiza and Brassica oleracea in removing nutrients from treated sewage effluent

The study investigates the capacity of phytoremediation as a post-treatment step for the nutrientrich- treated sewage effluent from Saga City sewage treatment plant, Saga, Japan. Phytoremediation in the context of this study is the removal of nutrients such as ammoniacal nitrogen, nitrate nitrogen and phosphorus from the nutrient-rich-treated sewage effluent by plants. In this study, Spirodela polyrhiza (S. polyrhiza) and Brassica oleracea (B. oleracea) were used to phytoremediate the treated sewage effluent collected from the Saga City Sewage Treatment Plant under laboratory scale. Plants were grown in polypropylene planter box supplied with 8,000 mL treated sewage effluent under indoor environment and full water retention throughout the experimental studies. The removal efficiency and daily absorption of nutrients by phytoremediation plants were determined. It was found that the most optimal removal efficiency and average daily nutrient removal rate by S. polyrhiza throughout the experiment were 92.42% ± 1.29% or 15.4 mg/L/d for ammoniacal nitrogen achieved in day 1, 78.69% ± 10.31% or 2.68 mg/L/d for nitrate-nitrogen achieved in day 4, and 93.45% ± 3.26% or 0.51 mg/L/d for phosphorus in day 3 of an experiment. On the other hand, the removal efficiency and average daily nutrient removal rate by B. oleracea throughout the experiment gave a total of 8 d where 76.07% ± 10.38% or 1.68 mg/L/d for ammoniacal nitrogen, 78.38% ± 0.40% or 1.19 mg/L/d for nitrate-nitrogen and 67.40% ± 10.91% or 0.10 mg/L/d for phosphorus. The overall findings demonstrated that phytoremediation by S. polyrhiza was far more effective in removing nutrients from the nutrient-rich-treated sewage effluent compared to B. oleracea. The significance of the study includes reducing the possibility of eutrophication outbreak caused by the disposal of treated sewage effluent, advocating less dependency on global demand for non-renewable phosphorus resources in the agriculture sector, and solving food demand due to the increasing world population

Typhonium flagelliforme inhibits the proliferation of murine leukemia WEHI-3 cells in vitro and induces apoptosis in vivo

Typhonium flagelliforme (TF) is a tropical plant, traditionally used by the ethnic population of Malaysia for the cure of various cancers. This plant had shown to induce antiproliferative effect as well as apoptosis in cancer cells. However, there is no available information to address that TF affects murine leukemia cells in vitro and in vivo. Here, we investigated in vitro and in vivo effects of TF on murine leukemia WEHI-3 cells. It was found that the growth of leukemia cells in vitro was inhibited by the various extracts of TF. Among these fractions, the dichloromethane (DCM) tuber extracts of TF showed the lowest IC50 (24.0±5.2g/ml) and had demonstrated apoptogenic effect when observed under fluorescent microscope.Weinvestigated the in vivo effects of DCM tuber extracts of TF on murine leukemia cells, and the results showed that the counts of immature granulocytes and monocytes were significantly decreased in peripheral blood of BALB/c leukemia mice after the oral administration of DCM tuber extracts of TF for 28 days with three doses (200, 400 and 800 mg/kg). These results were confirmed by observing the spleen histopathology and morphology of enlarged spleen and liver in leukemia micewhencompared with the control. Furthermore, the cell death mechanism in the spleen tissue of treated mice was found via apoptosis

Heavy fermions and two loop electroweak corrections to b→s+γb\rightarrow s+\gamma

Applying effective Lagrangian method and on-shell scheme, we analyze the electroweak corrections to the rare decay $b\rightarrow s+\gamma$ from some special two loop diagrams in which a closed heavy fermion loop is attached to the virtual charged gauge bosons or Higgs. At the decoupling limit where the virtual fermions in inner loop are much heavier than the electroweak scale, we verify the final results satisfying the decoupling theorem explicitly when the interactions among Higgs and heavy fermions do not contain the nondecoupling couplings. Adopting the universal assumptions on the relevant couplings and mass spectrum of new physics, we find that the relative corrections from those two loop diagrams to the SM theoretical prediction on the branching ratio of $B\rightarrow X_{_s}\gamma$ can reach 5% as the energy scale of new physics $\Lambda_{_{\rm NP}}=200$ GeV.Comment: 30 pages,4 figure

6-Methyl-3-phenyl-2-sulfanyl­idene-1,2,3,4-tetra­hydro­quinazolin-4-one

The title compound, C15H12N2OS, exists as the thione tautomer in the solid state. The phenyl group is almost perpendicular [dihedral angle = 87.96 (5)°] to the fused ring system (r.m.s. deviation = 0.036 Å for 13 ring and exocyclic non-H atoms). In the crystal, centrosymmetric dimers, sustained by pairs of N—H⋯S hydrogen bonds, are connected into layers parallel to (-101) by C—H⋯O and C—H⋯S inter­actions

2-Methyl-3-(2-methyl­phen­yl)-4-oxo-3,4-dihydro­quinazolin-8-yl thio­phene-2-carboxyl­ate

In the title compound, C21H16N2O3S, the central quinazolin-4-one ring is planar (r.m.s. deviation = 0.037 Å). The N-bound benzene and thio­phenyl rings are almost perpendicular to the central plane [dihedral angles = 82.22 (5) and 77.05 (13)°, respectively]. Mol­ecules are connected into a three-dimensional array by C—H⋯O inter­actions involving both carbonyl O atoms. The thio­phene ring is disordered over two positions, which are approximately parallel and oppositely orientated. The major component refined to a site-occupancy factor of 0.6555 (17)

4-Oxo-2,4-diphenyl­butane­nitrile

The title mol­ecule, C16H13NO, is twisted, the dihedral angle between the terminal phenyl rings being 68.40 (6)°. In the crystal, C—H⋯O and C—H⋯N inter­actions lead to supra­molecular layers in the bc plane