Aplikasi agens hayati dari perakaran bamboo dan rumput gajah untuk mengendalikan penyakit hawar daun dan peningkatan hasil tanaman pada sawi (Brassica rapa)

Penyakit Damping Off dan hawar daun merupakan penyakit yang sering ditemukan pada tanaman sawi (Brassica rapa) dan tanaman hortikultura sayuran lainnya. Kedua penyakit ini disebabkan oleh jamur Rizoctonia solani. Penggunaan bahan alam berbasis agens hayati mikroba merupakan solusi penanganan penyakit tanaman yang ramah lingkungan dan berkelanjutan, selain untuk pengendalian penyakit juga berpotensi meningkatkan hasil tanaman. Penelitian ini bertujuan untuk mengetahui efek aplikasi agens hayati dari perakaran bambu dan rumput gajah terhadap serangan penyakit hawar daun dan hasil tanaman sawi. Perlakuan yang dicobakan adalah agens hayati dari ekstrak akar bambu (EAB) dan akar rumput gajah (EARG), dan pupuk hayati konsorsium (PHK) dengan konsentrasi : PHK 1% , EAB 1%, EAB 1,5% , EAB 2%, EARG 1% , EARG 1,5%, EARG 2%, dan tanpa agens hayati sebagai kontrol. Percobaan dirancang menggunakan rancangan acak kelompok dengan tiga ulangan. Hasil penelitian adalah pemberian agens hayati dari EAB, EARG dan PHK dapat mengendalikan penyakit hawar daun, dan meningkatkan tinggi tanaman, bobot segar tanaman dan bobot kering tanaman. Agens hayati dengan konsentrasi terbaik adalah PHK 1%, EAB 2% dan EARG 2%. Hasil penelitian yang terbaik dapat direkomendasikan kepada petani untuk meningkatkan produksi tanaman sawi. ABSTRACT Damping off and leaf blight diseases are often found in mustard (Brassica rapa) and other vegetable horticultural crops. Both diseases are caused by a fungal pathogen Rizoctonia solani. The use of natural materials based on biological agents is a sustainable environmentally friendly solutions, besides controlling crop diseases, it also has the potential to increase crop yields. This study aims to determine the effect of application of biological agents from bamboo roots and elephant grass on leaf blight and mustard. The treatments involved biological agents extracted from bamboo roots (EAB) and elephant grass roots (EARG), and consortium bio-fertilizers (PHK) with concentrations of 1% layoff, EAB 1%, EAB 1.5%, EAB 2%, EARG 1%, EARG 1.5%, EARG 2%, and without biological agents as a control.  The experimental design was a randomized block design with three replications. The results of the study showed that the the application of biological agents from bamboo roots (EAB), elephant grass roots (EARG) and consortium bio-fertilizers (PHK) can control the leaf blight disease, and can increase the plant height, and the fresh and plant dry weight. The best concentration of biological agents is PHK 1%, EAB 2% and EARG 2%. The best results of this study can be recommended to farmers to increase the production of mustard plants.

Lagrangian and Hamiltonian two-scale reduction

Studying high-dimensional Hamiltonian systems with microstructure, it is an important and challenging problem to identify reduced macroscopic models that describe some effective dynamics on large spatial and temporal scales. This paper concerns the question how reasonable macroscopic Lagrangian and Hamiltonian structures can by derived from the microscopic system. In the first part we develop a general approach to this problem by considering non-canonical Hamiltonian structures on the tangent bundle. This approach can be applied to all Hamiltonian lattices (or Hamiltonian PDEs) and involves three building blocks: (i) the embedding of the microscopic system, (ii) an invertible two-scale transformation that encodes the underlying scaling of space and time, (iii) an elementary model reduction that is based on a Principle of Consistent Expansions. In the second part we exemplify the reduction approach and derive various reduced PDE models for the atomic chain. The reduced equations are either related to long wave-length motion or describe the macroscopic modulation of an oscillatory microstructure.Comment: 40 page

Bridging frustrated-spin-chain and spin-ladder physics: quasi-one-dimensional magnetism of BiCu2PO6

We derive and investigate the microscopic model of the quantum magnet BiCu2PO6 using band structure calculations, magnetic susceptibility and high-field magnetization measurements, as well as ED and DMRG techniques. The resulting quasi-one-dimensional spin model is a two-leg AFM ladder with frustrating next-nearest-neighbor couplings along the legs. The individual couplings are estimated from band structure calculations and by fitting the magnetic susceptibility with theoretical predictions, obtained using ED. The nearest-neighbor leg coupling J1, the rung coupling J4, and one of the next-nearest-neighbor couplings J2 amount to 120-150 K, while the second next-nearest-neighbor coupling is J2'~J2/2. The spin ladders do not match the structural chains, and although the next-nearest-neighbor interactions J2 and J2' have very similar superexchange pathways, they differ substantially in magnitude due to a tiny difference in the O-O distances and in the arrangement of non-magnetic PO4 tetrahedra. An extensive ED study of the proposed model provides the low-energy excitation spectrum and shows that the system is in the strong rung coupling regime. The strong frustration by the next-nearest-neighbor couplings leads to a triplon branch with an incommensurate minimum. This is further corroborated by a strong-coupling expansion up to second order in the inter-rung coupling. Based on high-field magnetization measurements, we estimate the spin gap of 32 K and suggest the likely presence of antisymmetric DM anisotropy and inter-ladder coupling J3. We also provide a tentative description of the physics of BiCu2PO6 in magnetic field, in the light of the low-energy excitation spectra and numerical calculations based on ED and DMRG. In particular, we raise the possibility for a rich interplay between one- and two-component Luttinger liquid phases and a magnetization plateau at 1/2 of the saturation value

Global modelling of the total OH reactivity: investigations on the “missing” OH sink and its atmospheric implications

The hydroxyl radical (OH) plays a crucial role in the chemistry of the atmosphere as it initiates the removal of most trace gases. A number of field campaigns have observed the presence of a “missing” OH sink in a variety of regions across the planet. A comparison of direct measurements of the OH loss frequency, also known as total OH reactivity (kOH), with the sum of individual known OH sinks (obtained via the simultaneous detection of species such as volatile organic compounds and nitrogen oxides) indicates that, in some cases, up to 80 % of kOH is unaccounted for. In this work, the UM-UKCA chemistry-climate model was used to investigate the wider implications of the missing reactivity on the oxidising capacity of the atmosphere. Simulations of the present-day atmosphere were performed and the model was evaluated against an array of field measurements to verify that the known OH sinks were reproduced well, with a resulting good agreement found for most species. Following this, an additional sink was introduced to simulate the missing OH reactivity as an emission of a hypothetical molecule, X, which undergoes rapid reaction with OH. The magnitude and spatial distribution of this sink were underpinned by observations of the missing reactivity. Model runs showed that the missing reactivity accounted for on average 6 % of the total OH loss flux at the surface and up to 50 % in regions where emissions of the additional sink were high. The lifetime of the hydroxyl radical was reduced by 3 % in the boundary layer, whilst tropospheric methane lifetime increased by 2 % when the additional OH sink was included. As no OH recycling was introduced following the initial oxidation of X, these results can be interpreted as an upper limit of the effects of the missing reactivity on the oxidising capacity of the troposphere. The UM-UKCA simulations also allowed us to establish the atmospheric implications of the newly characterised reactions of peroxy radicals (RO2) with OH. Whilst the effects of this chemistry on kOH were minor, the reaction of the simplest peroxy radical, CH3O2, with OH was found to be a major sink for CH3O2 and source of HO2 over remote regions at the surface and in the free troposphere. Inclusion of this reaction in the model increased tropospheric methane lifetime by up to 3 %, depending on its product branching. Simulations based on the latest kinetic and product information showed that this reaction cannot reconcile models with observations of atmospheric methanol, in contrast to recent suggestions

Enhanced Microlensing by Stars Around the Black Hole in the Galactic Center

The effect of stars on the lensing properties of the supermassive black hole in the Galactic Center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around SgrA* increases by factors of a few the probability of high-magnification lensing events of a distant background source by the black hole. Conversely, the gravitational shear of the black hole changes and enhances the microlensing properties of the individual stars. The effect is largest when the source image lies near the Einstein radius of the black hole 1.75"+/-0.20" for a source at infinity). We estimate that the probability of observing at least one distant background star which is magnified by a factor >5 in any infrared snapshot of the inner ~ 2" of the Galactic Center is 1% with a K-band detection threshold of 20 mag. The largest source of uncertainty in this estimate is the luminosity function of the background stars. The gravitational shear of the black hole lengthens the duration of high-magnification events near the Einstein radius up to a few months, and introduces a large variety of lightcurve shapes that are different from those of isolated microlenses. Identification of such events by image subtraction can be used to probe the mass function, density and velocity distributions of faint stars near the black hole, which are not detectable otherwise.Comment: 16 pages, 4 figures, ApJ in press. Lensing probability for GC significantly decreased due to revised background sources mode

Avaliação do teste imunocromatográfico ("ICT card test") no diagnóstico da filariose em estudos populacionais

This study evaluated the whole blood immunochromatographic card test (ICT card test) in a survey performed in Northeastern Brazil. 625 people were examined by the thick blood film (TBF) and ICT card test. Residents of a non-endemic area were also tested by the whole blood card test and Og4C3. The sensitivity of the ICT card test was 94.7% overall, but lower in females than males, based on the reasonable assumption that TBF is 100% specific. However, since TBF and other methods have unknown sensitivity, the true specificity of the card test is unknown. Nevertheless, it is possible to estimate upper and lower limits for the specificity, and relate it to the prevalence of the disease. In the endemic area, the possible range of the specificity was from 72.4% to 100%. 29.6% of the card tests performed in the non-endemic area exhibited faint lines that were interpreted as positives. Characteristics of the method including high sensitivity, promptness and simplicity justify its use for screening of filariasis. However, detailed information about the correct interpretation in case of extremely faint lines is essential. Further studies designed to consider problems arising from imperfect standards are necessary, as is a sounder diagnostic definition for the card test.Este estudo avaliou o teste imunocromatográfico ("ICT card test") em inquérito de filariose realizado no município de Olinda, Brasil. 625 pessoas foram examinadas pela técnica da gota espessa (GE), e "ICT card test" (ICT). Moradores do município de Campina Grande, Paraíba, área não endêmica, foram examinados pelos testes ICT e Og4C3-ELISA, para verificação da especificidade. A sensibilidade do método foi de 94,7%. O desenho do estudo - que envolveu a acurácia do ICT e do teste de referência (GE), em todos os elementos da amostra, - e a especificidade de 100% da GE permitiram o cálculo correto da sensibilidade. Todavia, como a sensibilidade da GE é desconhecida, a especificidade do ICT é ignorada. É possível, contudo, estimar o limite superior e inferior da especificidade e relacioná-la à prevalência de doença. Na área endêmica, a especificidade do teste variou entre 72,4% e 100,0%. 29,6% dos exames pelo ICT, realizados na área não endêmica, exibiram coloração tênue, tendo sido interpretados como positivos. Algumas características do método, incluindo alta sensibilidade, rapidez e simplicidade de execução justificam sua utilização em rastreamento de áreas endêmicas. Todavia, detalhes acerca da correta interpretação dos resultados com coloração extremamente tênue, parecem de importância fundamental

Doping effects in the coupled, two-leg spin ladder BiCu2PO6

We report preparation, x-ray diffraction, magnetic susceptibility chi(T) and heat capacity Cp(T) measurements on the undoped samples as also samples with Zn-doped (S = 0) at Cu site, Ni doped (S = 1) at Cu site, and Ca-doped (holes) at Bi site in the coupled two-leg spin ladder system BiCu2PO6. While, Zn shows complete solid solubility, Ni could be doped to about 20% and Ca to about 15%. Magnetization and heat capacity data in the undoped compound point towards the existence of frustration effects. In all the samples, the chi(T) at low temperature increases with doping content. The Zn-induced susceptibility is smaller than that due to effective S=1/2 moments possibly due to frustrating next-nearest-neighbor interactions along the leg. For Zn content x > 0.01, chi(T) deviates from the Curie-law at low temperatures. The magnetic specific heat data Cm(T) for the Zn-doped samples show weak anomalies at low temperature in agreement with chi(T) behavior. The anomalies are suggestive of spin freezing at low-T. In contrast, prominent effects are observed in chi(T) and Cm(T) on Ni-doped samples. The zero-field-cooled (ZFC) and field-cooled (FC) chi(T) data are different from each other at low temperature unlike that for Zn doped samples, clearly indicating a transition to a spin-glass like phase. No anomalies were found in Ca- or Pb-doped samples.Comment: 16 pages, 9 figures, Submitted to J. Phy. Cond. Matte