Magnetic properties of single-crystalline CeCuGa3

The magnetic behavior of single-crystalline CeCuGa3 has been investigated. The compound forms in a tetragonal BaAl4-type structure consisting of rare-earth planes separated by Cu-Ga layers. If the Cu-Ga site disorder is reduced, CeCuGa3 adopts the related, likewise tetragonal BaNiSn3-type structure, in which the Ce ion are surrounded by different Cu and Ga layers and the inversion symmetry is lost. In the literature conflicting reports about the magnetic order of CeCuGa3 have been published. Single crystals with the centrosymmetric structure variant exhibit ferromagnetic order below approx. 4 K with a strong planar anisotropy. The magnetic behavior above the transition temperature can be well understood by the crystal-field splitting of the 4f Hund's rule ground-state multiplet of the Ce ions

Finite-Temperature Transition in the Spin-Dimer Antiferromagnet BaCuSi2O6

We consider a classical XY-like Hamiltonian on a body-centered tetragonal lattice, focusing on the role of interlayer frustration. A three-dimensional (3D) ordered phase is realized via thermal fluctuations, breaking the mirror-image reflection symmetry in addition to the XY symmetry. A heuristic field-theoretical model of the transition has a decoupled fixed point in the 3D XY universality, and our Monte Carlo simulation suggests that there is such a temperature region where long-wavelength fluctuations can be described by this fixed point. However, it is shown using scaling arguments that the decoupled fixed point is unstable against a fluctuation-induced biquadratic interaction, indicating that a crossover to nontrivial critical phenomena with different exponents appears as one approaches the critical point beyond the transient temperature region. This new scenario clearly contradicts the previous notion of the 3D XY universality.Comment: 16 pages, 7 figure

X-Band ESR Determination of Dzyaloshinsky-Moriya Interaction in 2D SrCu2_2(BO3_3)2_2 System

X-band ESR measurements on a single crystal of SrCu$_2$(BO$_3$)$_2$ system in a temperature range between 10 K and 580 K are presented. The temperature and angular dependence of unusually broad ESR spectra can be explained by the inclusion of antisymmetric Dzyaloshinsky-Moriya (DM) interaction, which yields by far the largest contribution to the linewidth. However, the well-accepted picture of only out-of-plane interdimer DM vectors is not sufficient for explanation of the observed angular dependence. In order to account for the experimental linewidth anisotropy we had to include sizable in-plane components of interdimer as well as intradimer DM interaction in addition to the out-of-plane interdimer one. The nearest-neighbor DM vectors lie perpendicular to crystal anisotropy c-axis due to crystal symmetry. We also emphasize that above the structural phase transition occurring at 395 K dynamical mechanism should be present allowing for instantaneous DM interactions. Moreover, the linewidth at an arbitrary temperature can be divided into two contributions; namely, the first part arising from spin dynamics governed by the spin Hamiltonian of the system and the second part due to significant spin-phonon coupling. The nature of the latter mechanism is attributed to phonon-modulation of the antisymmetric interaction, which is responsible for the observed linear increase of the linewidth at high temperatures.Comment: 17 pages, 4 figures, submitted to PR

Pengaruh pengapuran dan pemupukkan P, K terhadap produktivitas dan kualitas buah papaya CV. Merah Muda di lahan rawa

Pepaya Merah Delima berpotensi untuk dibudidayakan di lahan rawa lebak. Permasalahan lahan rawa lebak yaitu pH rendah dan ketersediaan hara dalam tanah rendah sehingga perlu diberikan pengapuran dan pemupukan tambahan. Penelitian ini bertujuan untuk mendapatkan dosis kapur, pupuk P dan K terbaik untuk meningkatkan produktivitas dan kualitas pepaya Merah Delima. Penelitian dilakukan di lahan rawa lebak TTP Siak, Kecamatan Sai Mandau (BPTP Riau) dari bulan Januari 2018 sampai Desember 2019. Penelitian menggunakan Rancangan Petak Terbagi dengan petak utama yaitu dua taraf dosis kapur (6 dan 9 t ha-1) dan anak petak kombinasi dari tiga taraf dosis pupuk P2O5 (100, 200, 300 g tan-1) dan tiga taraf dosis pupuk K2O (150, 300, 450 g tan-1), setiap perlakuan terdapat tiga ulangan. Hasil penelitian menunjukkan pemberian kapur dosis 6 t ha-1 dan kombinasi P dan K dosis 300 g tan-1+ 300 g tan-1 berturut-turut, dapat meningkatkan produksi pepaya Merah Delima sampai 51% dengan rata-rata produksi 98,00 kg tan-1, jumlah buah rata-rata 95,45 tan-1, bobot buah 1.031,30 g buah-1, PTT 11,81 oBrix, dan kekerasan buah 55,08 kg cm-2. Pemberian kapur dan tambahan pupuk P dan K efektif untuk memperbaiki sifat lahan rawa lebak sehingga dapat meningkatkan hasil tanaman pepaya Merah Delima. Papaya CV. Merah Delima is potential to be cultivated on tidal swampland. The problems of tidal swampland are low degree of pH and low nutrient availability in the soil, thus it needs additional liming and fertilization. This study aimed to obtain the best dose of lime, also phosphorus and potassium fertilizers to increase the productivity and quality of papaya cv. Merah Delima. The study was conducted at TTP Siak, Sai Mandau district (BPTP Riau) from January 2018 to December 2019. The study used a Split Plot Design with the main plot was two doses of lime (6 and 9 t ha-1) and the subplot was combination of three doses of P2O5 fertilizer (100, 200, 300 g plant-1) and three levels of K2O fertilizer (150, 300, 450 g plant-1), with three replications. The results showed the application of lime at dose of 6 t ha-1 combined by P and  K fertilizer of 300 g plant-1 + 300 g plant-1, respectively, could increase papaya production up to 51%, whereas average production 98.00 kg plant-1, average number of fruits 95.45 plant-1, fruit weight 1,031.30 g fruit-1, TSS 11.81 °Brix, and fruit hardness of 55.08 kg cm-2. Application of lime and additional fertilizer into the tidal swampland are effective to improve its characteristics and able to increase the papaya Merah Delima production

Pengaruh pengapuran dan pemupukkan P, K terhadap produktivitas dan kualitas buah papaya CV. Merah Muda di lahan rawa

Pepaya Merah Delima berpotensi untuk dibudidayakan di lahan rawa lebak. Permasalahan lahan rawa lebak yaitu pH rendah dan ketersediaan hara dalam tanah rendah sehingga perlu diberikan pengapuran dan pemupukan tambahan. Penelitian ini bertujuan untuk mendapatkan dosis kapur, pupuk P dan K terbaik untuk meningkatkan produktivitas dan kualitas pepaya Merah Delima. Penelitian dilakukan di lahan rawa lebak TTP Siak, Kecamatan Sai Mandau (BPTP Riau) dari bulan Januari 2018 sampai Desember 2019. Penelitian menggunakan Rancangan Petak Terbagi dengan petak utama yaitu dua taraf dosis kapur (6 dan 9 t ha-1) dan anak petak kombinasi dari tiga taraf dosis pupuk P2O5 (100, 200, 300 g tan-1) dan tiga taraf dosis pupuk K2O (150, 300, 450 g tan-1), setiap perlakuan terdapat tiga ulangan. Hasil penelitian menunjukkan pemberian kapur dosis 6 t ha-1 dan kombinasi P dan K dosis 300 g tan-1+ 300 g tan-1 berturut-turut, dapat meningkatkan produksi pepaya Merah Delima sampai 51% dengan rata-rata produksi 98,00 kg tan-1, jumlah buah rata-rata 95,45 tan-1, bobot buah 1.031,30 g buah-1, PTT 11,81 oBrix, dan kekerasan buah 55,08 kg cm-2. Pemberian kapur dan tambahan pupuk P dan K efektif untuk memperbaiki sifat lahan rawa lebak sehingga dapat meningkatkan hasil tanaman pepaya Merah Delima. Papaya CV. Merah Delima is potential to be cultivated on tidal swampland. The problems of tidal swampland are low degree of pH and low nutrient availability in the soil, thus it needs additional liming and fertilization. This study aimed to obtain the best dose of lime, also phosphorus and potassium fertilizers to increase the productivity and quality of papaya cv. Merah Delima. The study was conducted at TTP Siak, Sai Mandau district (BPTP Riau) from January 2018 to December 2019. The study used a Split Plot Design with the main plot was two doses of lime (6 and 9 t ha-1) and the subplot was combination of three doses of P2O5 fertilizer (100, 200, 300 g plant-1) and three levels of K2O fertilizer (150, 300, 450 g plant-1), with three replications. The results showed the application of lime at dose of 6 t ha-1 combined by P and  K fertilizer of 300 g plant-1 + 300 g plant-1, respectively, could increase papaya production up to 51%, whereas average production 98.00 kg plant-1, average number of fruits 95.45 plant-1, fruit weight 1,031.30 g fruit-1, TSS 11.81 °Brix, and fruit hardness of 55.08 kg cm-2. Application of lime and additional fertilizer into the tidal swampland are effective to improve its characteristics and able to increase the papaya Merah Delima production

Some decidability issues concerning C^n real functions

This paper adapts preexisting decision algorithms to a family RDF = {RDFn | n ∈ N} of languages regarding one-argument real functions; each RDFn is a quantifier-free theory about the differentiability class C^n, embodying a fragment of Tarskian elementary algebra. The limits of decidability are also highlighted, by pointing out that certain extensions of RDFn are undecidable. The possibility of extending RDFn into a language RDF∞ regarding the class C^∞, without disrupting decidability, is briefly discussed. Two sorts of individual variables, namely real variables and function variables, are available in each RDFn. The former are used to construct terms and formulas that involve basic arithmetic operations and comparison relators between real terms, respectively. In contrast, terms designating functions involve function variables, constructs for addition of functions and scalar multiplication, and—outermost—i-th order differentiation D^i[ ] with i ⩽ n. An array of predicate symbols designate various relationships between functions, as well as function properties, that may hold over intervals of the real line; those are: function comparisons, strict and non-strict monotonicity / convexity / concavity, comparisons between a function (or one of its derivatives) and a real term. The decidability of RDFn relies, on the one hand, on Tarski’s celebrated decision algorithm for the algebra of real numbers, and, on the other hand, on reduction and interpolation techniques. An interpolation method, specifically designed for the case n = 1, has been previously presented; another method, due to Carla Manni, can be used when n = 2. For larger values of n, further research on interpolation is envisaged

Accurate Treatment of Large Supramolecular Complexes by Double-Hybrid Density Functionals Coupled with Nonlocal van der Waals Corrections

In this work, we present a thorough assessment of the performance of some representative double-hybrid density functionals (revPBE0-DH-NL and B2PLYP-NL) as well as their parent hybrid and GGA counterparts, in combination with the most modern version of the nonlocal (NL) van der Waals correction to describe very large weakly interacting molecular systems dominated by noncovalent interactions. Prior to the assessment, an accurate and homogeneous set of reference interaction energies was computed for the supramolecular complexes constituting the L7 and S12L data sets by using the novel, precise, and efficient DLPNO-CCSD(T) method at the complete basis set limit (CBS). The correction of the basis set superposition error and the inclusion of the deformation energies (for the S12L set) have been crucial for obtaining precise DLPNO-CCSD(T)/CBS interaction energies. Among the density functionals evaluated, the double-hybrid revPBE0-DH-NL and B2PLYP-NL with the three-body dispersion correction provide remarkably accurate association energies very close to the chemical accuracy. Overall, the NL van der Waals approach combined with proper density functionals can be seen as an accurate and affordable computational tool for the modeling of large weakly bonded supramolecular systems.Financial support by the “Ministerio de Economía y Competitividad” (MINECO) of Spain and European FEDER funds through projects CTQ2011-27253 and CTQ2012-31914 is acknowledged. The support of the Generalitat Valenciana (Prometeo/2012/053) is also acknowledged. J.A. thanks the EU for the FP7-PEOPLE-2012-IEF-329513 grant. J.C. acknowledges the “Ministerio de Educación, Cultura y Deporte” (MECD) of Spain for a predoctoral FPU grant

Resolving the neural circuits of anxiety

Although anxiety disorders represent a major societal problem demanding new therapeutic targets, these efforts have languished in the absence of a mechanistic understanding of this subjective emotional state. While it is impossible to know with certainty the subjective experience of a rodent, rodent models hold promise in dissecting well-conserved limbic circuits. The application of modern approaches in neuroscience has already begun to unmask the neural circuit intricacies underlying anxiety by allowing direct examination of hypotheses drawn from existing psychological concepts. This information points toward an updated conceptual model for what neural circuit perturbations could give rise to pathological anxiety and thereby provides a roadmap for future therapeutic development.National Institute of Diabetes and Digestive and Kidney Diseases (U.S.) (NIH Director’s New Innovator Award DP2-DK-102256-01)National Institute of Mental Health (U.S.) (NIH) R01-MH102441-01)JPB Foundatio

Optogenetic strategies to investigate neural circuitry engaged by stress

Optogenetic techniques have given researchers unprecedented access to the function of discrete neural circuit elements and have been instrumental in the identification of novel brain pathways that become dysregulated in neuropsychiatric diseases. For example, stress is integrally linked to the manifestation and pathophysiology of neuropsychiatric illness, including anxiety, addiction and depression. Due to the heterogeneous populations of genetically and neurochemically distinct neurons in areas such as the bed nucleus of the stria terminalis (BNST), as well as their substantial number of projections, our understanding of how neural circuits become disturbed after stress has been limited. Using optogenetic tools, we are now able to selectively isolate distinct neural circuits that contribute to these disorders and perturb these circuits in vivo, which in turn may lead to the normalization of maladaptive behavior. This review will focus on current optogenetic strategies to identify, manipulate, and record from discrete neural circuit elements in vivo as well as highlight recent optogenetic studies that have been utilized to parcel out BNST function

Involvement of protein kinase A in ethanol-induced locomotor activity and sensitization

Mutant mice lacking the RIIβ subunit of protein kinase A (regulatory subunit II beta−/−) show increased ethanol preference. Recent evidence suggests a relationship between heightened ethanol preference and susceptibility to ethanol-induced locomotor sensitization. It is currently unknown if protein kinase A signaling modulates the stimulant effects and/or behavioral sensitization caused by ethanol administration. To address this question, we examined the effects of repeated ethanol administration on locomotor activity RIIβ−/− and littermate wild-type (RIIβ+/+) mice on multiple genetic backgrounds