1,046 research outputs found

    Exact Effective action for (1+1)-dimensional fermions in an Abelian background at finite temperature and chemical potential

    Full text link
    In this paper we study the effects of a nonzero chemical potential in the effective action for massless fermions in (1+1) dimensions in an abelian gauge field background at finite temperature. We calculate the n-point function and show that the structure of the amplitudes corresponds to a generalization of the structure noted earlier in a calculation without a chemical potential (the associated integrals carry the dependence on the chemical potential). Our calculation shows that the chiral anomaly is unaffected by the presence of a chemical potential at finite temperature. However, unlike the earlier calculation (in the absence of a chemical potential) odd point functions do not vanish. We trace this to the fact that in the presence of a chemical potential the generalized charge conjugation symmetry of the theory allows for such amplitudes. In fact, we find that all the even point functions are even functions of the chemical potential while the odd point functions are odd functions of it which is consistent with this generalized charge conjugation symmetry. We show that the origin of the structure of the amplitudes is best seen from a formulation of the theory in terms of left and right handed spinors. The calculations are also much simpler in this formulation and it clarifies many other aspects of the theory

    Identification of fullerene-like CdSe nanoparticles from optical spectroscopy calculations

    Full text link
    Semiconducting nanoparticles are the building blocks of optical nanodevices as their electronic states, and therefore light absorption and emission, can be controlled by modifying their size and shape. CdSe is perhaps the most studied of these nanoparticles, due to the efficiency of its synthesis, the high quality of the resulting samples, and the fact that the optical gap is in the visible range. In this article, we study light absorption of CdSe nanostructures with sizes up to 1.5 nm within density functional theory. We study both bulk fragments with wurtzite symmetry and novel fullerene-like core-cage structures. The comparison with recent experimental optical spectra allows us to confirm the synthesis of these fullerene-like CdSe clusters

    Kajian nilai lingkungan hidup dalam teks kakawin durmanggala dan teks kakawin atlas bhumi dalam upaya mengondisikan lingkungan lestari harmonis

    Get PDF
    Nilai-nilai yang terkandung dalam naskah atau dokumen tertulis melalui semua aspek kehidupan budaya bangsa mencakup bidang-bidang filsafat, agama, kepemimpinan, ajaran dan hal lain yang menyangkut kebutuhan hidup. Karena itu menggali, meneliti, dan menelusuri karya sastra dalam naskah-naskah kuno di berbagai daerah di lndonesia pada hakekatnya sangat diperlukan dalam rangka pembentukan manusia Indonesia seutuhnya

    Factorization of finite temperature graphs in thermal QED

    Full text link
    We extend our previous analysis of gauge and Dirac fields in the presence of a chemical potential. We consider an alternate thermal operator which relates in a simple way the Feynman graphs in QED at finite temperature and charge density to those at zero temperature but non-zero chemical potential. Several interesting features of such a factorization are discussed in the context of the thermal photon and fermion self-energies.Comment: 4 page

    Thermal Operator and Cutting Rules at Finite Temperature and Chemical Potential

    Get PDF
    In the context of scalar field theories, both real and complex, we derive the cutting description at finite temperature (with zero/finite chemical potential) from the cutting rules at zero temperature through the action of a simple thermal operator. We give an alternative algebraic proof of the largest time equation which brings out the underlying physics of such a relation. As an application of the cutting description, we calculate the imaginary part of the one loop retarded self-energy at zero/finite temperature and finite chemical potential and show how this description can be used to calculate the dispersion relation as well as the full physical self-energy of thermal particles.Comment: 17 pages, 13 figures. Added references, version to appear in Physical Review

    The mediating role of psychological flexibility in the relationship between resilience and distress and quality of life in people with multiple sclerosis

    Get PDF
    The purpose of this study is to investigate the role of psychological flexibility in mediating the beneficial effects of resilience on distress and quality of life (QoL) in people with MS (PwMS). The psychological flexibility framework underpinning acceptance and commitment therapy (ACT) was used to conceptualise psychological flexibility. A total of 56 PwMS completed an online survey that assessed global psychological flexibility and each of its six core sub-processes, resilience, distress, mental and physical health QoL, socio-demographics, and illness variables. Mediation analyses showed that, as hypothesised, higher levels of global psychological flexibility and its sub-processes were associated with increases in the positive impacts of resilience on distress and mental and physical health QoL via a mediational mechanism. These findings suggest that psychological flexibility skills build resilience capacities in PwMS. The psychological flexibility framework offers an ACT-based intervention pathway to build resilience and enhance mental health and QoL in PwMS

    Ekstraksi Emas Dari Limbah Papan Sirkuit Telepon Genggam Menggunakan Teknik Membran Cair Emulsi

    Get PDF
    Penelitian ini bertujuan untuk menentukan persen ekstraksi emas dari limbah papan sirkuit telepon genggam dengan teknik membran cair emulsi menggunakan MIBK sebagai carrier. Reaksinya terjadi secara simultan di permukaan membran, antara senyawa yang akan dipisahkan pada fasa umpan dengan senyawa pembawa pada fasa organik. Logam emas hasil reaksi akan terdifusi ke fasa membran yang pada akhirnya hasil ekstraksi terkumpul dan terkonsentrasi di fasa penerima. Sebelum diaplikasikan ke limbah telepon , terlebih dahulu dipelajari beberapa parameter yang berpengaruh terhadap perolehan persen ekstraksi. Pada penelitian ini kondisi optimum untuk parameter pembuatan fasa emulsi yaitu 1:1, pengaruh kecepatan pembuatan emulsi pada yaitu 1000 rpm.Pengaruh konsentrasi carrier terhadap persen ekstraksi emas dengan konsentrasi MIBK sebesar 3%, pengaruh kecepatan kontak terhadap persen ekstraksi emas adalah pada 1000 rpm. Penerapan kondisi optimum pada limbah papan sirkuit telepon genggam memberikan persen ekstraksi Au sebesar 83.24%. Kata Kunci: limbah papan sirkuit telepon genggam, MIBK, teknik membran cair emulsi. Abstrack This research aim is to determine extraction percentage of gold from cellular phone circuit board waste using emulsion liquid membrane technique with Methyl Isobutyl Ketone (MIBK) as carrier. The reaction occur simultaneously on the membrane surface, between compound going to be separate in feed phase with carrier compound in organic phase. Gold from reaction will diffuse into membrane phase which finally will be collected and concentrated in receiving phase. Before it applied to phone waste, there are several parameters studied which influence the extraction percentage result. In this research the optimum condition for building emulsion phase parameter is 1:1, effect on building emulsion rate is 1000 rpm. Carrier concentration effect to extraction percentage of gold is at 3% MIBK and contact rate effect is at 1000 rpm. Optimum condition application to cellular phone circuit board waste give Au extraction percentage of 83.24%

    Struktur Histologi Otot Femur Kelinci (Lepus SP.) Setelah Perlakuan Implantasi Material Stainless Steel Aisi 316l Selama 2,5 Bulan

    Full text link
    Production implant orthopedic domestic with 316L Stainless steel base material which use the material dimensions of the Indonesian non-import until now hasn't been researched. Research the effect of implantation of these materials to health conditions need to be conducted on animal models, such as the rabbit before it wad applied to humans. This study aims to determine the histological changes in the femoral muscle of rabbits after implantation of AISI 316L stainless steel for 2.5 months, as part of the basic data for further research in order to figure out orthopedic implants that can be used by the body. This study compared the P0: rabbit was not given implantation of stainless steel AISI 316L with P1: Rabbits were given treatment AISI 316L stainless steel implants in the quadriceps femoris muscle parallel to the femur bone. Implantation of the implant material was conducted for 2.5 months. Histological changes observed were the presence or absence of necrosis, fibrosis and tissue cavities in the rabbit femoral muscle tissue. The results showed there were no three variables were observed. It is concluded AISI 316L stainless steel did not cause structural changes in muscle histology in a rabbit femur after implantation for 2.5 months; so that these materials can be used as an implant material in the body

    Identification of psychological flexibility and inflexibility profiles during the COVID-19 pandemic

    Get PDF
    BackgroundThe first coronavirus disease 2019 (COVID-19) wave and lockdown adversely affected the lives of people in diverse ways. AimsThis study used a person-centered approach to identify patterns of engagement in the 12 psychological flexibility (PF) and inflexibility (PI) processes to manage the first COVID-19 wave and lockdown hardships. Materials & MethodsA total of 1035 Italian adults completed an online survey. ResultsLatent profile analyses conducted on the 12 PI/PF processes measured by the Multidimensional Psychological Flexibility Inventory identified five profiles; three reflected gradations of high to low PF with corresponding inverse levels of PI, while two represented more complex relationships between PI and PF. After controlling for relevant socio-demographic and COVID-19/lockdown factors, the five profiles differed in mental health (depression, anxiety, and COVID-19 distress). Essentially a gradient of progressive decreases in all PI processes (except experiential avoidance) corresponded with increments in mental health across all profiles. Two profiles, which evidenced the highest levels of mental health (highly flexible and moderately flexible profiles), also had the greatest proportion of the sample 56.42% (n = 584), and the highest levels of PF and experiential avoidance. DiscussionFindings from this and similar studies suggest intersecting complex relationships among the PI/PF processes that are likely to shift in response to changing contexts. We suggest this network of relationships is better represented by a three-dimensional PF/PI hexaflex than a simplistic two-dimensional depiction of the model. ConclusionDistinguishing different PF/PI profiles identified groups most at risk for the adverse mental health impacts of the pandemic and exposed variations in the mental health protective and risk roles of PF and PI processes, respectively, that can inform ACT-based mental health promotion interventions
    corecore