A Supersymmetric SYK-like Tensor Model

We consider a supersymmetric SYK-like model without quenched disorder that is built by coupling two kinds of fermionic N=1 tensor-valued superfields, "quarks" and "mesons". We prove that the model has a well-defined large-N limit in which the (s)quark 2-point functions are dominated by mesonic "melon" diagrams. We sum these diagrams to obtain the Schwinger-Dyson equations and show that in the IR, the solution agrees with that of the supersymmetric SYK model.Comment: 29 pages, 19 figures. v2: 3 references and more details of the computation in section 3.1 are adde

Welfare Analysis of the Number and Locations of Local Public Facilities

We develop a discrete or finite household model with congestable local public goods where the level of provision, the number of facilities and their locations are all endogenously determined in a purely normative context. We prove the existence of an equal-treatment identical-provision second best optimum, where all households are required to reach the same utility level, the provision of local public good is required to be the same at all facilities, and all facilities must serve the same number of consumers. Such an optimal public facility configuration may or may not be geographically centralized if there is only a single public facility site. Moreover, the optimal public facility configuration could be either concentrated (single site) or dispersed (multiple sites), depending crucially on the degree of congestability and the household valuation of the local public good as well as the commuting cost.Congestable Local Public Goods, Optimal Public Facility Configurations

Taxing pollution: agglomeration and welfare consequences

This paper demonstrates that a pollution tax with a fixed cost component may lead, by itself, to segregation between clean and dirty firms without heterogeneous preferences or increasing returns. We construct a simple model with two locations and two industries (clean and dirty) where pollution is a by-product of dirty good manufacturing. Under proper assumptions, a completely stratified configuration with all dirty firms clustering in one city emerges as the only equilibrium outcome when there is a fixed cost component of the pollution tax. Moreover, a stratified Pareto optimum can never be supported by a competitive spatial equilibrium with a linear pollution tax. To support such a stratified Pareto optimum, however, an effective but unconventional policy prescription is to redistribute the pollution tax revenue from the dirty to the clean city residents.Pollution Tax; Agglomeration of Polluting Producers; Endogenous Stratification

Welfare Analysis of the Number and Locations of Local Public Facilities

We develop a model with a finite number of households and congestable local public goods where the level of provision, the number of facilities and their locations are all endogenously determined. We prove that an equal-treatment identical-provision second-best optimum exists, where all households are required to reach the same utility level, the provision of local public good is required to be the same at all facilities, and all facilities must serve the same number of consumers. Such an optimal public facility configuration may be concentrated (single site) or dispersed (multiple sites), depending on congestability, commuting cost and the household preference parameters.Congestable Local Public Goods, Optimal Public Facility Configurations

Skin Mast Cells Contribute to Sporothrix schenckii Infection

Background: Sporothrix schenckii (S. schenckii), a dimorphic fungus, causes sporotrichosis. Mast cells (MCs) have been described to be involved in skin fungal infections. The role of MCs in cutaneous sporotrichosis remains largely unknown. Objectives: To characterize the role and relevance of MCs in cutaneous sporotrichosis. Methods: We analyzed cutaneous sporotrichosis in wild-type (WT) mice and two different MC-deficient strains. In vitro, MCs were assessed for S. schenckii-induced cytokine production and degranulation after incubation with S. schenckii. We also explored the role of MCs in human cutaneous sporotrichosis. Results: WT mice developed markedly larger skin lesions than MC-deficient mice (> 1.5 fold) after infection with S. schenckii, with significantly increased fungal burden. S. schenckii induced the release of tumor necrosis factor alpha (TNF), interleukin (IL)-6, IL-10, and IL-1β by MCs, but not degranulation. S. schenckii induced larger skin lesions and higher release of IL-6 and TNF by MCs as compared to the less virulent S. albicans. In patients with sporotrichosis, TNF and IL-6 were increased in skin lesions, and markedly elevated levels in the serum were linked to disease activity. Conclusions: These findings suggest that cutaneous MCs contribute to skin sporotrichosis by releasing cytokines such as TNF and IL-6

AFV1, a novel virus infecting hyperthermophilic archaea of the genus acidianus

AbstractWe describe a novel virus, AFV1, of the hyperthermophilic archaeal genus Acidianus. Filamentous virions are covered with a lipid envelope and contain at least five different proteins with molecular masses in the range of 23–130 kDa and a 20.8-kb-long linear double-stranded DNA. The virus has been assigned to the family Lipothrixviridae on the basis of morphotypic characteristics. Host range is confined to several strains of Acidianus and the virus persists in its hosts in a stable carrier state. The latent period of virus infection is about 4 h. Viral DNA was sequenced and sequence similarities were found to the lipothrixvirus SIFV, the rudiviruses SIRV1 and SIRV2, as well as to conjugative plasmids and chromosomes of the genus Sulfolobus. Exceptionally for the linear genomes of archaeal viruses, many short direct repeats, with the sequence TTGTT or close variants thereof, are closely clustered over 300 bp at each end of the genome. They are reminiscent of the telomeric ends of linear eukaryal chromosomes

Improving feature location using structural similarity and iterative graph mapping

Locating program element(s) relevant to a particular feature is an important step in efficient maintenance of a software system. The existing feature location techniques analyze each feature independently and perform a one-time analysis after being provided an initial input. As a result, these techniques are sensitive to the quality of the input. In this paper, we propose to address the above issues in feature location using an iterative context-aware approach. The underlying intuition is that features are not independent of each other, and the structure of source code resembles the structure of features. The distinguishing characteristics of the proposed approach are: (1) it takes into account the structural similarity between a feature and a program element to determine feature-element relevance; (2) it employs an iterative process to propagate the relevance of the established mappings between a feature and a program element to the neighboring features and program elements. We evaluate our approach using two different systems, DirectBank, a small-scale industry financial system, and Linux kernel, a large-scale open-source operating system. Our evaluation suggests that the proposed approach is more robust and can significantly increase the recall of feature location with only a minor decrease of precision

Thioredoxin reductase 1 suppresses adipocyte differentiation and insulin responsiveness

Recently thioredoxin reductase 1 (TrxR1), encoded by Txnrd1, was suggested to modulate glucose and lipid metabolism in mice. Here we discovered that TrxR1 suppresses insulin responsiveness, anabolic metabolism and adipocyte differentiation. Immortalized mouse embryonic fibroblasts (MEFs) lacking Txnrd1 (Txnrd1−/−) displayed increased metabolic flux, glycogen storage, lipogenesis and adipogenesis. This phenotype coincided with upregulated PPARγ expression, promotion of mitotic clonal expansion and downregulation of p27 and p53. Enhanced Akt activation also contributed to augmented adipogenesis and insulin sensitivity. Knockdown of TXNRD1 transcripts accelerated adipocyte differentiation also in human primary preadipocytes. Furthermore, TXNRD1 transcript levels in subcutaneous adipose tissue from 56 women were inversely associated with insulin sensitivity in vivo and lipogenesis in their isolated adipocytes. These results suggest that TrxR1 suppresses anabolic metabolism and adipogenesis by inhibition of intracellular signaling pathways downstream of insulin stimulationThis study was supported by funding to ESJA from Karolinska Institutet, The Swedish Research Council, The Swedish Cancer Society, to MR from the Strategic Research Program in Diabetes and to ACG from Diabetesfonden and a “Ramón y Cajal” fellowship (RYC-2014-15792) from Spanish Ministerio de Economía y Competitivida