191 research outputs found

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

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    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

    Magnetic properties of single-crystalline CeCuGa3

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    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

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    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

    Optogenetic strategies to investigate neural circuitry engaged by stress

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    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

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    Mutant mice lacking the RIIÎČ 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 RIIÎČ−/− and littermate wild-type (RIIÎČ+/+) mice on multiple genetic backgrounds

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

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    X-band ESR measurements on a single crystal of SrCu2_2(BO3_3)2_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

    Activation of Prefrontal Cortical Parvalbumin Interneurons Facilitates Extinction of Reward-Seeking Behavior

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    Forming and breaking associations between emotionally salient environmental stimuli and rewarding or aversive outcomes is an essential component of learned adaptive behavior. Importantly, when cue-reward contingencies degrade, animals must exhibit behavioral flexibility to extinguish prior learned associations. Understanding the specific neural circuit mechanisms that operate during the formation and extinction of conditioned behaviors is critical because dysregulation of these neural processes is hypothesized to underlie many of the maladaptive and pathological behaviors observed in various neuropsychiatric disorders in humans. The medial prefrontal cortex (mPFC) participates in the behavioral adaptations seen in both appetitive and aversive-cue-mediated responding, but the precise cell types and circuit mechanisms sufficient for driving these complex behavioral states remain largely unspecified. Here, we recorded and manipulated the activity of parvalbumin-positive fast spiking interneurons (PV+ FSIs) in the prelimbic area (PrL) of the mPFC in mice. In vivo photostimulation of PV+ FSIs resulted in a net inhibition of PrL neurons, providing a circuit blueprint for behavioral manipulations. Photostimulation of mPFC PV+ cells did not alter anticipatory or consummatory licking behavior during reinforced training sessions. However, optical activation of these inhibitory interneurons to cues associated with reward significantly accelerated the extinction of behavior during non-reinforced test sessions. These data suggest that suppression of excitatory mPFC networks via increased activity of PV+ FSIs may enhance reward-related behavioral flexibility

    Amygdala and bed nucleus of the stria terminalis circuitry: Implications for addiction-related behaviors

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    Complex motivated behavioral processes, such as those that can go awry following substance abuse and other neuropsychiatric disorders, are mediated by a distributive network of neurons that reside throughout the brain. Neural circuits within the amygdala regions, such as the basolateral amygdala (BLA), and downstream targets such as the bed nucleus of the stria terminalis (BNST), are critical neuroanatomical structures for orchestrating emotional behavioral responses that may influence motivated actions such as the reinstatement of drug seeking behavior. Here, we review the functional neurocircuitry of the BLA and the BNST, and discuss how these circuits may guide maladaptive behavioral processes such as those seen in addiction. Thus, further study of the functional connectivity within these brain regions and others may provide insight for the development of new treatment strategies for substance use disorders

    Inhibition of projections from the basolateral amygdala to the entorhinal cortex disrupts the acquisition of contextual fear

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    The development of excessive fear and/or stress responses to environmental cues such as contexts associated with a traumatic event is a hallmark of post-traumatic stress disorder (PTSD). The basolateral amygdala (BLA) has been implicated as a key structure mediating contextual fear conditioning. In addition, the hippocampus has an integral role in the encoding and processing of contexts associated with strong, salient stimuli such as fear. Given that both the BLA and hippocampus play an important role in the regulation of contextual fear conditioning, examining the functional connectivity between these two structures may elucidate a role for this pathway in the development of PTSD. Here, we used optogenetic strategies to demonstrate that the BLA sends a strong glutamatergic projection to the hippocampal formation through the entorhinal cortex (EC). Next, we photoinhibited glutamatergic fibers from the BLA terminating in the EC during the acquisition or expression of contextual fear conditioning. In mice that received optical inhibition of the BLA-to-EC pathway during the acquisition session, we observed a significant decrease in freezing behavior in a context re-exposure session. In contrast, we observed no differences in freezing behavior in mice that were only photoinhibited during the context re-exposure session. These data demonstrate an important role for the BLA-to-EC glutamatergic pathway in the acquisition of contextual fear conditioning
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