Casimir effect of Lorentz-violating charged Dirac in background magnetic field

We study the effect of the Lorentz symmetry breaking on the Casimir energy of charged Dirac in the presence of a uniform magnetic field. We use the boundary condition from the MIT bag model to represent the property of the plates. We investigate two cases of the direction of violation, namely, time-like and space-like vector cases. We discuss how the Lorentz violation and the magnetic field affect the structure of the Casimir energy and its pressure. We also investigate the weak and strong magnetic field cases with two different limits, heavy and light masses.Comment: 17 pages, 5 figure

Architects of time: Labouring on digital futures

Drawing on critical analyses of the internet inspired by Gilles Deleuze and the Marxist autonomia movement, this paper suggests a way of understanding the impact of the internet and digital culture on identity and social forms through a consideration of the relationship between controls exercised through the internet, new subjectivities constituted through its use and new labour practices enabled by it. Following Castells, we can see that the distinction between user, consumer and producer is becoming blurred and free labour is being provided by users to corporations. The relationship between digital technologies and sense of community, through their relationship to the future, is considered for its dangers and potentials. It is proposed that the internet may be a useful tool for highlighting and enabling social connections if certain dangers can be traversed. Notably, current remedies for the lack of trust on the internet are questioned with an alternative, drawing on Zygmunt Bauman and Georg Simmel, proposed which is built on community through a vision of a ‘shared network’

Sex ratio distorting microbes exacerbate arthropod extinction risk in variable environments

Maternally-inherited sex ratio distorting microbes (SRDMs) are common among arthropod species. Typically, these microbes cause female-biased sex ratios in host broods, either by; killing male offspring, feminising male offspring, or inducing parthenogenesis. As a result, infected populations can experience drastic ecological and evolutionary change. The mechanism by which SRDMs operate is likely to alter their impact on host evolutionary ecology; despite this, the current literature is heavily biased towards a single mechanism of sex ratio distortion, male-killing. Furthermore, amidst the growing concerns surrounding the loss of arthropod diversity, research into the impact of SRDMs on the viability of arthropod populations is generally lacking. In this study, using a theoretical approach, we model the epidemiology of an understudied mechanism of microbially-induced sex ratio distortion—feminisation—to ask an understudied question—how do SRDMs impact extinction risk in a changing environment? We constructed an individual-based model and measured host population extinction risk under various environmental and epidemiological scenarios. We also used our model to identify the precise mechanism modulating extinction. We find that the presence of feminisers increases host population extinction risk, an effect that is exacerbated in highly variable environments. We also identified transmission rate as the dominant epidemiological trait responsible for driving extinction. Finally, our model shows that sex ratio skew is the mechanism driving extinction. We highlight feminisers and, more broadly, SRDMs as important determinants of the resilience of arthropod populations to environmental change

Bariatric Surgery can Lead to Net Cost Savings to Health Care Systems: Results from a Comprehensive European Decision Analytic Model.

The objective of the present study was to evaluate the cost-utility of bariatric surgery in a lifetime horizon from a Swedish health care payer perspective. A decision analytic model using the Markov process was developed covering cardiovascular diseases, type 2 diabetes, and surgical complications. Clinical effectiveness and safety were based on the literature and data from the Scandinavian Obesity Surgery Registry. Gastric bypass, sleeve gastrectomy, and gastric banding were included in the analysis. Cost data were obtained from Swedish sources. Bariatric surgery was cost saving in comparison with conservative management. It also led to a substantial reduction in lifetime risk of events: from a 16 % reduction in the risk of transient ischaemic attacks to a 62 % reduction in the incidence of type 2 diabetes. Over a lifetime, surgery led to savings of a,not sign8408 and generated an additional 0.8 years of life and 4.1 quality-adjusted life years (QALYs) per patient, which translates into gains of 32,390 quality-adjusted person-years and savings of a,not sign66 million for the cohort, operated in 2012. Analysis of the consequences of a 3-year delay in surgery provision showed that the overall lifetime cost of treatment may be increased in patients with diabetes or a body mass index > 40 kg/m(2). Delays in surgery may also lead to a loss of clinical benefits: up to 0.6 life years and 1.2 QALYs per patient over a lifetime. Bariatric surgery, over a lifetime horizon, may lead to significant cost savings to health care systems in addition to the known clinical benefits

Eksperimentasi Tekstur Cetak Kolase Sampah Anorganik dalam Penciptaan Karya Seni Grafis

Latar belakang penelitian ini berdasarkan pengamatan peneliti terhadap permasalahan sampah di Yogyakarta yang belum maksimal ditangani. Masih banyak oknum yang dengan sadar membuang sampah sembarangan di pinggir jalan atau lahan kosong. Selain itu budaya konsumtif masyarakat juga menjadi salah satu faktor penyebab banyaknya sampah yang dihasilkan, khususnya sampah anorganik yang sulit terurai. Latar belakang secara personal yaitu dari kebiasaan penulis yang sering menyimpan barang bekas/sampah anorganik yang sekiranya masih layak pakai. Hal tersebut dikarenakan barang bekas dirasa masih akan bermanfaat di kemudian hari. Tujuan dari penelitian ini adalah untuk mewujudkan kreativitas perancangan karya seni grafis cetak tinggi dengan memanfaatkan sampah anorganik. Perancangan ini juga bertujuan sebagai alternatif material bahan yang mudah ditemukan dan lebih ekonomis dalam media pembelajaran mata kuliah Seni Grafis Dasar. Selain itu juga sebagai bentuk dukungan gerakan zero sampah anorganik yang saat ini sedang dilaksanakan di Yogyakarta sejak awal tahun 2023. Visualisasi karya yang akan dihadirkan yaitu suasana bangunan perkotaan secara realistik, dalam artian objek yang dihadirkan sama dengan kenyataannya. Sehingga diperlukan eksperimentasi tekstur hasil cetakan sampah anorganik yang merupakan perwujudan gagasan estetik berdasarkan pengalaman empiris peneliti. Metode penelitian ini menggunakan pendekatan practice-led research yang dilakukan melalui perancangan karya seni grafis teknik cetak tinggi dengan berfokus pada eksperimentasi tekstur cetak kolase sampah anorganik. Tahapan metode dalam penelitian ini menggunakan metode perancangan kreatif seni yaitu: eksplorasi (pengumpulan, pemilahan bahan dan eksperimentasi tekstur cetak), perancangan, dan perwujudan, dengan menerapkan teknik kolase cetak tinggi pada media 2 dimensi. Luaran yang ditargetkan adalah jurnal terakreditasi minimal sinta 5 dan rancangan karya yang dihasilkan terdaftar Kekayaan Intelektual (karya seni yang didaftarkan hak cipta). Output dari penelitian ini adalah karya seni 2 dimensi. Level TKT Penelitian yang dilakukan adalah level 5, yaitu Validasi komponen/subsistem dalam suatu lingkungan yang relevan

Casimir effect of Lorentz-violating charged Dirac field in background magnetic field

We study the effect of the Lorentz violation on the Casimir energy and pressure of a charged Dirac field in a background uniform magnetic field. In the model, the Lorentz violation is parameterized not only by the intensity but also by its direction. We investigate two cases of the direction of violation, namely, time-like and space-like vector cases. We use the boundary condition of the MIT bag model to represent the property of the plates. We show how the Lorentz violation and the magnetic field affect the structure of the Casimir energy and its pressure. We also investigate the weak and strong magnetic field cases with two different limits, heavy and light masses. In addition, we compute the ratio of the influence of the strong magnetic field to that of the weak one for the Casimir energy and its pressure. We find that the strong magnetic field enhances the magnitude of the Casimir energy and its pressure, where the parameter of the intensity of Lorentz violation could scale the plate’s distanc

Violation of the two-time Leggett-Garg inequalities for a harmonic oscillator

We investigate the violation of the Leggett-Garg inequalities for a harmonic oscillator in various quantum states. We focus on the two-time quasi-probability distribution function with a dichotomic variable constructed with the position operator of a harmonic oscillator. First, we developed a new formula to compute the two-time quasi-probability distribution function, whose validity is demonstrated in comparison with the formula developed in the recent paper by Mawby and Halliwell[Phys.Rev.A, 107 032216 (2023)]. Second, we demonstrated the variety of the violation of the two-time Leggett-Garg inequalities assuming various quantum states of a harmonic oscillator including the squeezed coherent state and the thermal squeezed coherent state. Third, we demonstrated that a certain type of extension of the dichotomic variable and the corresponding projection operator can boost violation of the Leggett-Garg inequalities for the ground state and the squeezed state. We also discuss when the Leggett-Garg inequalities are violated in an intuitive manner.Comment: 17 pages, 8 figure

Fluctuating selection models and Mcdonald-Kreitman type analyses

It is likely that the strength of selection acting upon a mutation varies through time due to changes in the environment. However, most population genetic theory assumes that the strength of selection remains constant. Here we investigate the consequences of fluctuating selection pressures on the quantification of adaptive evolution using McDonald-Kreitman (MK) style approaches. In agreement with previous work, we show that fluctuating selection can generate evidence of adaptive evolution even when the expected strength of selection on a mutation is zero. However, we also find that the mutations, which contribute to both polymorphism and divergence tend, on average, to be positively selected during their lifetime, under fluctuating selection models. This is because mutations that fluctuate, by chance, to positive selected values, tend to reach higher frequencies in the population than those that fluctuate towards negative values. Hence the evidence of positive adaptive evolution detected under a fluctuating selection model by MK type approaches is genuine since fixed mutations tend to be advantageous on average during their lifetime. Never-the-less we show that methods tend to underestimate the rate of adaptive evolution when selection fluctuates

Geometric Control of Universal Hydrodynamic Flow in a Two-Dimensional Electron Fluid

Fluid dynamics is one of the cornerstones of modern physics and has recently found applications in the transport of electrons in solids. In most solids, electron transport is dominated by extrinsic factors, such as sample geometry and scattering from impurities. However, in the hydrodynamic regime, Coulomb interactions transform the electron motion from independent particles to the collective motion of a viscous "electron fluid."The fluid viscosity is an intrinsic property of the electron system, determined solely by the electron-electron interactions. Resolving the universal intrinsic viscosity is challenging, as it affects the resistance only through interactions with the sample boundaries, whose roughness not only is unknown but also varies from device to device. Here, we eliminate all unknown parameters by fabricating samples with smooth sidewalls to achieve the perfect slip boundary condition, which has been elusive in both molecular fluids and electronic systems. We engineer the device geometry to create viscous dissipation and reveal the true intrinsic hydrodynamic properties of a 2D system. We observe a clear transition from ballistic to hydrodynamic electron motion, driven by both temperature and magnetic field. We directly measure the viscosity and electron-electron scattering lifetime (the Fermi quasiparticle lifetime) over a wide temperature range without fitting parameters and show they have a strong dependence on electron density that cannot be explained by conventional theories based on the random phase approximation

Dynamic walking features and improved walking performance in multiple sclerosis patients treated with fampridine (4-aminopyridine)

Background: Impaired walking capacity is a frequent confinement in Multiple Sclerosis (MS). Patients are affected by limitations in coordination, walking speed and the distance they may cover. Also abnormal dynamic walking patterns have been reported, involving continuous deceleration over time. Fampridine (4-aminopyridine), a potassium channel blocker, may improve walking in MS. The objective of the current study was to comprehensively examine dynamic walking characteristics and improved walking capacity in MS patients treated with fampridine. Methods: A sample of N = 35 MS patients (EDSS median: 4) underwent an electronic walking examination prior to (Time 1), and during treatment with fampridine (Time 2). Patients walked back and forth a distance of 25 ft for a maximum period of 6 min (6-minute 25-foot-walk). Besides the total distance covered, average speed on the 25-foot distance and on turns was determined separately for each test minute, at Time 1 and Time 2. Results: Prior to fampridine administration, 27/35 patients (77 %) were able to complete the entire 6 min of walking, while following the administration, 34/35 patients (97 %) managed to walk for 6 min. In this context, walking distance considerably increased and treatment was associated with faster walking and turning across all six test minutes (range of effect sizes: partial eta squared = .34-.72). Importantly, previously reported deceleration across test minutes was consistently observable at Time 1 and Time 2. Discussion: Fampridine administration is associated with improved walking speed and endurance. Regardless of a treatment effect of fampridine, the previously identified, abnormal dynamic walking feature, i.e. the linear decline in walking speed, may represent a robust feature. Conclusions: The dynamic walking feature might hence be considered as a candidate for a new outcome measure in clinical studies involving interventions other than symptomatic treatment, such as immune-modulating medication. Trial registration: DRKS00009228 (German Clinical Trials Register). Date obtained: 25.08.2015