Fibers and global geometry of functions

Since the seminal work of Ambrosetti and Prodi, the study of global folds was enriched by geometric concepts and extensions accomodating new examples. We present the advantages of considering fibers, a construction dating to Berger and Podolak's view of the original theorem. A description of folds in terms of properties of fibers gives new perspective to the usual hypotheses in the subject. The text is intended as a guide, outlining arguments and stating results which will be detailed elsewhere

Fibrin-mediated Protection Against Infection-stimulated Immunopathology

Fibrin, a product of the blood coagulation cascade, accompanies many type 1 immune responses, including delayed-type hypersensitivity, autoimmunity, and graft rejection. In those settings, fibrin is thought to exacerbate inflammation and disease. Here, we evaluate roles for coagulation during infection with Toxoplasma gondii, a pathogen whose control requires robust type 1 immunity. We establish that fibrin prevents infection-stimulated blood loss, thereby performing a protective function that is essential for survival. Remarkably, fibrin does not simply protect against vascular damage caused directly by the infectious agent, but rather, protects against hemorrhage evoked by interferon-γ, a critical mediator of type 1 immunity. This finding, to our knowledge, is the first to document a beneficial role for coagulation during type 1 immunity, and suggests that fibrin deposition protects host tissue from collateral damage caused by the immune system as it combats infection

Fibrinogen regulates the cytotoxicity of mycobacterial trehalose dimycolate, but is not required for cell recruitment, cytokine response, or control of mycobacterial infection

During inflammatory responses and wound healing, the conversion of soluble fibrinogen to fibrin, an insoluble extracellular matrix, long has been assumed to create a scaffold for the migration of leukocytes and fibroblasts. Previous studies concluded that fibrinogen is a necessary cofactor for mycobacterial trehalose 6,6-dimycolate-induced responses, because trehalose dimycolate-coated beads, to which fibrinogen was ad-sorbed, were more inflammatory than those to which other plasma proteins were adsorbed. Herein, we investigate roles for fibrin(ogen) in an in vivo model of mycobacterial granuloma formation and in infection with Mycobacterium tuberculosis, the causative agent of tuberculosis. In wild-type mice, the subcutaneous injection of trehalose dimycolate-coated polystyrene microspheres, suspended within Matrigel, elicited a pyogranulomatous response during the course of 12 days. In fibrinogen-deficient mice, neutrophils were recruited but a more suppurative lesion developed, with the marked degradation and disintegration of the matrix. Compared to that in wild-type mice, the early formation of granulation tissue in fibrinogen-deficient mice was edematous, hypocellular, and disorganized. These deficiencies were complemented by the addition of exogenous fibrinogen. The absence of fibrinogen had no effect on cell recruitment or cytokine production i

Aristotle’s assertoric syllogistic and modern relevance logic

This paper sets out to evaluate the claim that Aristotle’s Assertoric Syllogistic is a relevance logic or shows significant similarities with it. I prepare the grounds for a meaningful comparison by extracting the notion of relevance employed in the most influential work on modern relevance logic, Anderson and Belnap’s Entailment. This notion is characterized by two conditions imposed on the concept of validity: first, that some meaning content is shared between the premises and the conclusion, and second, that the premises of a proof are actually used to derive the conclusion. Turning to Aristotle’s Prior Analytics, I argue that there is evidence that Aristotle’s Assertoric Syllogistic satisfies both conditions. Moreover, Aristotle at one point explicitly addresses the potential harmfulness of syllogisms with unused premises. Here, I argue that Aristotle’s analysis allows for a rejection of such syllogisms on formal grounds established in the foregoing parts of the Prior Analytics. In a final section I consider the view that Aristotle distinguished between validity on the one hand and syllogistic validity on the other. Following this line of reasoning, Aristotle’s logic might not be a relevance logic, since relevance is part of syllogistic validity and not, as modern relevance logic demands, of general validity. I argue that the reasons to reject this view are more compelling than the reasons to accept it and that we can, cautiously, uphold the result that Aristotle’s logic is a relevance logic

The Detector System for the Stratospheric Kinetic Inductance Polarimeter (SKIP)

The Stratospheric Kinetic Inductance Polarimeter (SKIP) is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1133 square degrees of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (LEKID). The LEKIDs will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and rotated by a superconducting magnetic bearing. The observation program consists of at least two, five-day flights beginning with the 150 GHz observations.Comment: J Low Temp Phys DOI 10.1007/s10909-013-1014-3 The final publication is available at link.springer.co