Computing fractal dimension in supertransient systems directly, fast and reliable

Chaotic transients occur in many experiments including those in fluids, in simulations of the plane Couette flow, and in coupled map lattices and they are a common phenomena in dynamical systems. Superlong chaotic transients are caused by the presence of chaotic saddles whose stable sets have fractal dimensions that are close to phase-space dimension. For many physical systems chaotic saddles have a big impact on laboratory measurements, and it is important to compute the dimension of such stable sets including fractal basin boundaries through a direct method. In this work, we present a new method to compute the dimension of stable sets of chaotic saddles directly, fast, and reliable.Comment: 6 pages, 3 figure

Free vibration of thermally loaded panels including initial imperfections and post-buckling effects

A combined theoretical and experimental approach is developed to consider the small amplitude free vibration characteristics of fully clamped panels under the influence of uniform heating. Included in this study are the effects of higher modes, in-plane boundary elasticity, initial imperfections, and post-buckling. Comparisons between theory and experiment reveal excellent agreement

Pengembangan Website Untuk Pembelajaran Analisis Struktur Rangka Dengan Metode Kekakuan Langsung

Seiring dengan perkembangan zaman, internet telah menjadi sarana yang tidak dapat dipisahkan dalam kehidupan sehari-hari, termasuk dalam bidang edukasi. Dewasa ini, telah terdapat beberapa website perhitungan analisa struktur yang tersedia. Namun website tersebut masih belum dapat mengakomodasi kebutuhan pembelajaran secara utuh. Oleh karena itu, dibutuhkan website edukatif dan interaktif yang dapat membantu pemahaman dalam mata kuliah Analisa Struktur III dan Metode Elemen Hingga.Pemilihan metode kekakuan langsung dilakukan karena metode ini merupakan implementasi dasar dan praktis untuk metode elemen hingga berbasis perpindahan. Di samping itu, metode ini secara de facto telah menjadi metode standar pada software komersial untuk analisis struktur. Sementara itu, algoritma perhitungan akan diimplementasikan ke dalam bahasa pemrograman HTML, PHP, JavaScript, dan jQuery.Dari hasil program, diketahui bahwa secara umum program sudah dapat membantu perhitungan analisis struktur rangka, termasuk pada struktur yang tidak stabil. Akan tetapi, pada analisa yang hanya memperhitungkan deformasi geser, perlu dilakukan modifikasi pada koefisien geser

Differentiation and Protective Capacity of Virus-Specific CD8

Noroviruses can establish chronic infections with active viral shedding in healthy humans but whether persistence is associated with adaptive immune dysfunction is unknown. We used genetically engineered strains of mouse norovirus (MNV) to investigate CD8+ T cell differentiation during chronic infection. We found that chronic infection drove MNV-specific tissue-resident memory (Trm) CD8+ T cells to a differentiation state resembling inflationary effector responses against latent cytomegalovirus with only limited evidence of exhaustion. These MNV-specific Trm cells remained highly functional yet appeared ignorant of ongoing viral replication. Pre-existing MNV-specific Trm cells provided partial protection against chronic infection but largely ceased to detect virus within 72 hours of challenge, demonstrating rapid sequestration of viral replication away from T cells. Our studies revealed a strategy of immune evasion by MNV via the induction of a CD8+ T cell program normally reserved for latent pathogens and persistence in an immune-privileged enteric niche. Chronic infections often cause T cell dysfunction, but how noroviruses (NV) evade immunity is unknown. Tomov et al. show that gut-resident T cells against NV remain functional but ignorant of chronic viral replication, suggesting that NV persists in an immune-privileged enteric niche. © 2017 Elsevier Inc

A mechanistic basis for potent, glycoprotein B-directed gammaherpesvirus neutralization

Glycoprotein B (gB) is a conserved, essential component of gammaherpes virions and so potentially vulnerable to neutralization. However, few good gB-specific neutralizing antibodies have been identified. Here, we show that murid herpesvirus 4 is strongly neutralized by mAbs that recognize an epitope close to one of the gB fusion loops. Antibody binding did not stop gB interacting with its cellular ligands or initiating its fusion-associated conformation change, but did stop gB resolving stably to its post-fusion form, and so blocked membrane fusion to leave virions stranded in late endosomes. The conservation of gB makes this mechanism a possible general route to gammaherpesvirus neutralization

ATG5 regulates plasma cell differentiation

Autophagy is a conserved homeostatic process in which cytoplasmic contents are degraded and recycled. Two ubiquitin-like conjugation pathways are required for the generation of autophagosomes, and ATG5 is necessary for both of these processes. Studies of mice deficient in ATG5 reveal a key role for autophagy in T lymphocyte function, as well as in B cell development and B-1a B cell maintenance. However, the role of autophagy genes in B cell function and antibody production has not been described. Using mice in which Atg5 is conditionally deleted in B lymphocytes, we showed here that this autophagy gene is essential for plasma cell homeostasis. In the absence of B cell ATG5 expression, antibody responses were significantly diminished during antigen-specific immunization, parasitic infection and mucosal inflammation. Atg5-deficient B cells maintained the ability to produce immunoglobulin and undergo class-switch recombination, yet had impaired SDC1 expression, significantly decreased antibody secretion in response to toll-like receptor ligands, and an inability to upregulate plasma cell transcription factors. These results build upon previous data demonstrating a role for ATG5 in early B cell development, illustrating its importance in late B cell activation and subsequent plasma cell differentiation

Identification of Alternative Transcripts Encoding the Essential Murine Gammaherpesvirus Lytic Transactivator RTA

The essential immediate early transcriptional activator RTA, encoded by gene 50, is conserved among all characterized gammaherpesviruses. Analyses of a recombinant murine gammaherpesvirus 68 (MHV68) lacking both of the known gene 50 promoters (G50DblKo) revealed that this mutant retained the ability to replicate in the simian kidney epithelial cell line Vero but not in permissive murine fibroblasts following low-multiplicity infection. However, G50DblKo replication in permissive fibroblasts was partially rescued by high-multiplicity infection. In addition, replication of the G50DblKo virus was rescued by growth on mouse embryonic fibroblasts (MEFs) isolated from IFN-α/βR(−/−) mice, while growth on Vero cells was suppressed by the addition of alpha interferon (IFN-α). 5′ rapid amplification of cDNA ends (RACE) analyses of RNAs prepared from G50DblKo and wild-type MHV68-infected murine macrophages identified three novel gene 50 transcripts initiating from 2 transcription initiation sites located upstream of the currently defined proximal and distal gene 50 promoters. In transient promoter assays, neither of the newly identified gene 50 promoters exhibited sensitivity to IFN-α treatment. Furthermore, in a single-step growth analysis RTA levels were higher at early times postinfection with the G50DblKo mutant than with wild-type virus but ultimately fell below the levels of RTA expressed by wild-type virus at later times in infection. Infection of mice with the MHV68 G50DblKo virus demonstrated that this mutant virus was able to establish latency in the spleen and peritoneal exudate cells (PECs) of C57BL/6 mice with about 1/10 the efficiency of wild-type virus or marker rescue virus. However, despite the ability to establish latency, the G50DblKo virus mutant was severely impaired in its ability to reactivate from either latently infected splenocytes or PECs. Consistent with the ability to rescue replication of the G50DblKo mutant by growth on type I interferon receptor null MEFs, infection of IFN-α/βR(−/−) mice with the G50DblKo mutant virus demonstrated partial rescue of (i) acute virus replication in the lungs, (ii) establishment of latency, and (iii) reactivation from latency. The identification of additional gene 50/RTA transcripts highlights the complex mechanisms involved in controlling expression of RTA, likely reflecting time-dependent and/or cell-specific roles of different gene 50 promoters in controlling virus replication. Furthermore, the newly identified gene 50 transcripts may also act as negative regulators that modulate RTA expression. IMPORTANCE The viral transcription factor RTA, encoded by open reading frame 50 (Orf50), is well conserved among all known gammaherpesviruses and is essential for both virus replication and reactivation from latently infected cells. Previous studies have shown that regulation of gene 50 transcription is complex. The studies reported here describe the presence of additional alternatively initiated, spliced transcripts that encode RTA. Understanding how expression of this essential viral gene product is regulated may identify new strategies for interfering with infection in the setting of gammaherpesvirus-induced diseases

Discrimination, labour markets and the Labour Market Prospects of Older Workers: What Can a Legal Case Teach us?

As governments become increasingly concerned about the fiscal implications of the ageing population, labour market policies have sought to encourage mature workers to remain in the labour force. The ‘human capital’ discourses motivating these policies rest on the assumption that older workers armed with motivation and vocational skills will be able to return to fulfilling work. This paper uses the post-redundancy recruitment experiences of former Ansett Airlines flight attendants to develop a critique of these expectations. It suggests that policies to increase older workers’ labour market participation will not succeed while persistent socially constructed age- and gender- typing shape labour demand. The conclusion argues for policies sensitive to the institutional structures that shape employer preferences, the competitive rationality of discriminatory practices, and the irresolvable tension between workers’ human rights and employers’ property rights