161 research outputs found

    Microlocal spectrum condition and Hadamard form for vector-valued quantum fields in curved spacetime

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    Some years ago, Radzikowski has found a characterization of Hadamard states for scalar quantum fields on a four-dimensional globally hyperbolic spacetime in terms of a specific form of the wavefront set of their two-point functions (termed `wavefront set spectrum condition'), thereby initiating a major progress in the understanding of Hadamard states and the further development of quantum field theory in curved spacetime. In the present work, we extend this important result on the equivalence of the wavefront set spectrum condition with the Hadamard condition from scalar fields to vector fields (sections in a vector bundle) which are subject to a wave-equation and are quantized so as to fulfill the covariant canonical commutation relations, or which obey a Dirac equation and are quantized according to the covariant anti-commutation relations, in any globally hyperbolic spacetime having dimension three or higher. In proving this result, a gap which is present in the published proof for the scalar field case will be removed. Moreover we determine the short-distance scaling limits of Hadamard states for vector-bundle valued fields, finding them to coincide with the corresponding flat-space, massless vacuum states.Comment: latex2e, 41 page

    Analisis Peluang USAha Petani Kopi Rakyat Desa Garahan Kabupaten Jember melalui Agribisnis Jamur Merang dengan Pemanfaatan Limbah Kulit Kopi [ Analysis Of Business Opportunity Coffee Farmers Through The Village Garahan Jember Agribusiness Mushroom Leathe

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    Pemanfaatan limbah perkebunan kopi yang dihasilkan setiap hari dapat dijadikan peluang suatu USAha yang kreatif, inovatif dan bernilai ekonomi. Limbah kulit biji kopi di sekitar perkebunan kopi Desa Garahan Kecamatan Silo Kabupaten Jember merupakan peluang USAha baru bagi masyarakat sekitar perkebunan yaitu agribisnis jamur merang (Volvaria volvaceae) dimana tujuan akhirnya adalah untuk meningkatkan kesejahteraan masyarakat khususnya petani kopi takyat yang ada di desa tersebut. Penelitian ini bertujuan untuk mengembangkan USAha agribisnis jamur merang yang belum ada sebelumnya melalui pemanfaatan limbah kulit biji kopi sebagai media pertumbuhannya dan pada akhirnya mampu meningkatkan kesejahteraan masyarakat sekitar. Metode analisis yang digunakan adalah analisis SWOT, yaitu analisis menggunkan faktor internal (IFAS) dan faktor eksternal (EFAS), dengan mengetahui streght (kekuatan), weaknesess (kelemahan), oppurtunities (peluang), advantange (keuntungan), threat (ancaman). Berdasarkan hasil analisis faktor-faktor strategi internal diperoleh nilai IFAS sebesar 3,06 dan hasil analisis faktor-faktor strategi eksternal diperoleh nilai EFAS sebesar 2,27. Nilai tersebut menempatkan USAhatani jamur merang melalui pemanfaatan limbah kulit kopi di Desa Garahan Kec.Silo Kabupaten Jember dalam posisi White area (Bidang Kuat-Berpeluang) yang artinya USAha tersebut memiliki peluang pasar yang prospektif dan memiliki kompotensi untuk mengerjakannya

    New-generation biocompatible Ti-based metallic glass ribbons for flexible implants

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    We introduce five new biocompatible Ti-based metallic glass (MG) compositions with different metalloid and soft metal content for a synergistic improvement in corrosion properties. Without any potentially harmful elements such as Cu, Ni or Be, these novel alloys can eliminate the risk of inflammatory reaction when utilized for permanent medical implants. Excluding Cu, Ni or Be, which are essential for Ti-based bulk MG production, on the other hand, confines the glass-forming ability of novel alloys to a moderate level. In this study, toxic-element free MG alloys with significant metalloid (Si–Ge–B, 15–18 at.%) and minor soft element (Sn, 2–5 at.%) additions are produced in ribbon form using conventional single-roller melt spinning technique. Their glass-forming abilities and their structural and thermal properties are comparatively investigated using X-ray diffraction (XRD), synchrotron XRD and differential scanning calorimetry. Their corrosion resistance is ascertained in a biological solution to analyze their biocorrosion properties and compare them with other Ti-based bulk MGs along with energy dispersive X-ray. Ti60Zr20Si8Ge7B3Sn2 and Ti50Zr30Si8Ge7B3Sn2 MG ribbons present a higher pitting potential and passivation domain compared with other Ti-based MG alloys tested in similar conditions. Human mesenchymal stem cell metabolic activity and cytocompatibility tests confirm their outstanding cytocompatibility, outperforming Ti-Al6-V4

    Generation of cytocompatible superhydrophobic Zr–Cu–Ag metallic glass coatings with antifouling properties for medical textiles

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    Zirconium–Copper-based metallic glass thin films represent promising coatings in the biomedical sector for their combination of antibacterial property and wear resistance. However, finding a Zr–Cu metallic glass composition with desirable cytocompatibility and antibacterial property is extremely challenging. In this work, we have created a cytocompatible and (super-)hydrophobic Zr–Cu–Ag metallic glass coating with ≈95% antifouling properties. First, a range of different chemical compositions were prepared via Physical Vapor Deposition magnetron by co-sputtering Zr, Cu, and Ag onto a Polybutylene terephthalate (PBT) substrate among which Zr93·5Cu6·2Ag0.2, Zr76·7Cu22·7Ag0.5, and Zr69·3Cu30·1Ag0.6 were selected to be further investigate for their surface properties, antibacterial activity, and cytocompatibility. Scanning electron microscopy (SEM) images revealed a micro-roughness fibrous structure holding superhydrophobic properties demonstrated by specimens' static and dynamic contact angle measurements ranging from 130° to 150°. The dynamic contact angle measurements have shown hysteresis below 10° for all coated samples which indicated the superhydrophobicity of the samples. To distinguish between antifouling and bactericidal effect of the coating, ions release from coatings into Luria Bertani Broth (LB), and Dulbecco's Modified Eagle Medium (DMEM) solutions were evaluated by inductively coupled plasma mass spectrometry (ICP-MS) measurements after 24 ​h and 5 days. Antifouling properties were evaluated by infecting the specimens' surface with the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli strain reporting a ≈95% reduction of bacteria adhesion as visually confirmed by FESEM and fluorescent live/dead staining. Human mesenchymal stem cells (hMSC) were used for direct cytocompatibility evaluation of coated samples and their metabolic activity was evaluated via relative fluorescence unit after 24 ​h and 5 days confirming that it was comparable to the controls (>97% viable cells). The results were further visualized by FESEM, fluorescent staining by Live/Dead Viability/Cytotoxicity Kit and confirmed the cytocompatibility of all coated samples. Finally, hMSC′ cytoplasm was stained by May Grunwald and Giemsa after 5days to detect and visualize the released ions which have diffused through the cells' membrane

    A Generalized Modular Multilevel Current Source Inverter

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    This paper proposes a novel topology of multilevel current source inverter which is suitable to apply in low/medium voltage. The proposed topology is capable of producing desirable bidirectional output current levels. Furthermore, it can employ symmetrical DC current sources as well as asymmetrical ones which is a significant advantage. Asymmetrical mode makes it possible to generate a great number of output levels by appropriate selection of DC current source magnitude, needless to make changes in the hardware of the inverter. As a result, various methods are presented to compute the magnitude of needed DC current sources. In comparison to the conventional H-Bridge inverter (CHB), the proposed inverter has lessened the number of required DC current sources, switches as well as related gate driver circuits. The reduced number of required components has leads to cost and volume advantages. In addition, the control layout has become simpler. Reduction of power loss as a result of reduced number of on-state switches is the other merit of the proposed inverter. To evaluate the efficiency of the proposed inverter, its simulation and experimental results are extracted including results of various methods of determining DC current source magnitude

    Vlasov simulations of electron acceleration by radio frequency heating near the upper hybrid layer

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    It is shown by using a combination of Vlasov and test particles simulations that the electron distribution function resulting from energization due to Upper Hybrid (UH) plasma turbulence depends critically on the closeness of the pump wave to the double resonance, defined as omega≈omega_UH≈n omega_ce where n is an integer. For pump frequencies, away from the double resonance the electron distribution function is very close to Maxwellian, while as the pump frequency approaches the double resonance it develops a high energy tail. The simulations show turbulence involving coupling between Lower Hybrid (LH) and UH waves, followed by excitation of Electron Bernstein (EB) modes. For the particular case of a pump with frequency between n=3 and n=4 the EB modes cover the range from the first to the 5th mode. The simulations show that when the injected wave frequency is between the 3rd and 4th electron cyclotron frequency, bulk electron heating occurs due to the interaction between the electrons and large amplitude EB waves, primarily on the first EB branch leading to an essentially thermal distribution. On the other hand, when the frequency is slightly above the 4th electron cyclotron harmonic, the resonant interaction is predominantly due to the UH branch and leads to a further acceleration of high-velocity electrons and a distribution function with a suprathermal tail of energetic electrons. The results are consistent with ionospheric experiments and relevant to the production of Artificial Ionospheric Plasma Layers

    Renormalised fermion vacuum expectation values on anti-de Sitter space-time

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    The Schwinger–de Witt and Hadamard methods are used to obtain renormalised vacuum expectation values for the fermion condensate, charge current and stress-energy tensor of a quantum fermion field of arbitrary mass on four-dimensional anti-de Sitter space–time. The quantum field is in the global anti-de Sitter vacuum state. The results are compared with those obtained using the Pauli–Villars and zeta-function regularisation methods, respectively

    Attractor states and infrared scaling in de Sitter space

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    The renormalized expectation value of the energy-momentum tensor for a scalar field with any mass m and curvature coupling xi is studied for an arbitrary homogeneous and isotropic physical initial state in de Sitter spacetime. We prove quite generally that has a fixed point attractor behavior at late times, which depends only on m and xi, for any fourth order adiabatic state that is infrared finite. Specifically, when m^2 + xi R > 0, approaches the Bunch-Davies de Sitter invariant value at late times, independently of the initial state. When m = xi = 0, it approaches instead the de Sitter invariant Allen-Folacci value. When m = 0 and xi \ge 0 we show that this state independent asymptotic value of the energy-momentum tensor is proportional to the conserved geometrical tensor (3)H_{ab}, which is related to the behavior of the quantum effective action of the scalar field under global Weyl rescaling. This relationship serves to generalize the definition of the trace anomaly in the infrared for massless, non-conformal fields. In the case m^2 + xi R = 0, but m and xi separately different from zero, grows linearly with cosmic time at late times. For most values of m and xi in the tachyonic cases, m^2 + xi R grows exponentially at late cosmic times for all physically admissable initial states.Comment: 30 pages, 6 figures, 46 kB tar.gz fil

    A longitudinal investigation of repressive coping and ageing

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Aging & Mental Health on October 2016, available online: http://www.tandfonline.com/doi/full/10.1080/13607863.2015.1060941.Two studies investigated the possibility that repressive coping is more prevalent in older adults and that this represents a developmental progression rather than a cohort effect. Study 1 examined repressive coping and mental health cross-sectionally in young and old adults. Study 2 examined whether there was a developmental progression of repressive coping prevalence rates in a longitudinal sample of older adults.Peer reviewedFinal Accepted Versio

    First-in-Human Clinical Trial of Oral ONC201 in Patients with Refractory Solid Tumors

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    Purpose: ONC201 is a small-molecule selective antagonist of the G protein–coupled receptor DRD2 that is the founding member of the imipridone class of compounds. A first-in-human phase I study of ONC201 was conducted to determine its recommended phase II dose (RP2D). Experimental Design: This open-label study treated 10 patients during dose escalation with histologically confirmed advanced solid tumors. Patients received ONC201 orally once every 3 weeks, defined as one cycle, at doses from 125 to 625 mg using an accelerated titration design. An additional 18 patients were treated at the RP2D in an expansion phase to collect additional safety, pharmacokinetic, and pharmacodynamic information. Results: No grade \u3e 1 drug-related adverse events occurred, and the RP2D was defined as 625 mg. Pharmacokinetic analysis revealed a Cmax of 1.5 to 7.5 μg/mL (∼3.9–19.4 μmol/L), mean half-life of 11.3 hours, and mean AUC of 37.7 h·μg/L. Pharmacodynamic assays demonstrated induction of caspase-cleaved keratin 18 and prolactin as serum biomarkers of apoptosis and DRD2 antagonism, respectively. No objective responses by RECIST were achieved; however, radiographic regression of several individual metastatic lesions was observed along with prolonged stable disease (\u3e 9 cycles) in prostate and endometrial cancer patients. Conclusions: ONC201 is a selective DRD2 antagonist that is well tolerated, achieves micromolar plasma concentrations, and is biologically active in advanced cancer patients when orally administered at 625 mg every 3 weeks
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