804 research outputs found
Can Fregeans have 'I'-thoughts?
We examine how Frege?s contrast between identity judgments of the forms ?a=a? vs. ?a=b? would fare in the special case where ?a? and ?b? are complex mental representations, and ?a? stands for an introspected ?I?-thought. We first argue that the Fregean treatment of I-thoughts entails that they are what we call ?one-shot thoughts?: they can only be thought once. This has the surprising consequence that no instance of the ?a=a? form of judgment in this specific case comes out true, let alone a priori true. This further reinforces Glezakos?s objections against the set-up of Frege?s puzzle, while also raising what we think is an acute problem for Fregeans, insofar as I-thought (and indexical thinking more generally), understood in their way, turns out to be incompatible with some basic features of rationality
Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands
We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K
A study on transparency of a passive manipulation mechanism : application to Neoditech Scara Parts
International audienceIn the field of 5 to 100 kg load transportation in workshops, many systems having more or less complex ar-chitectures have been developed to reduce musculo-skeletal disorders (hoists, pliers, dedicated systems). These systems offer different behaviors and human interaction is far from being the same for all of them. In recent years, the literature produced a lot of work around design thinking, user-centered approaches emphasizing notions around perception, cognition, and ergonomics to meet the needs of the end user. The development of cobotics and more generally systems allowing the interaction or co-manipulation of objects highlights the notion of transparency of the system. This transparency is expressed as the fact of feeling only a part of the physical magnitudes of the object most relevant to the user in his manipulation. In the context of this article, we study the transparency of a kinematically redundant passive mechanism based on a scara one (revolute joints parallel between them) when manipulating heavy objects on a plane. This article is based on a state of the art of different criteria in order to evaluate the behavior of a robot such as manipulability or dexterity. We will indicate the relevance of these criteria that we apply to a theoretical study. These theoretical aspects will then be evaluated on Neoditech Scara Parts arm. It is a mechanism capable of handling up to 50kg composed of a plane arm mounted on vertical linear axis itself mounted on a fixed or mobile base. This plane arm consists of 6 revolute joints having parallel axes ensuring redundancy in the architecture of the robot
Thyroid hormone receptor {beta} (TR{beta}) and liver X receptor (LXR) regulate carbohydrate response element binding protein (ChREBP) expression in a tissue selective manner.
Thyroid hormone- (TR) and Liver X- (LXR)receptors are transcription factors involved in lipogenesis. Both receptors recognize the same consensus DNA response element in vitro. It was previously shown that their signalling pathways interact in the control of cholesterol elimination in the liver. In the present study ChREBP, a major transcription factor controlling the activation of glucose-induced lipogenesis in liver, is characterized as a direct target of thyroid hormones(TH) in liver and white adipose tissue(WAT), the two main lipogenic tissues in mice. Using genetic and molecular approaches ChREBP is shown to be specifically regulated by TRbeta, but not by TRalpha in vivo even in WAT where both TR isoforms are expressed. However this isotype specificity is not found in vitro. This TRbeta specific regulation correlates with the loss of TH-induced lipogenesis in TRbeta-/- mice. Fasting/refeeding experiments show that TRbeta is not required for the activation of ChREBP expression particularly marked in WAT following refeeding. However TH can stimulate ChREBP expression in WAT even under fasting conditions suggesting completely independent pathways. Since ChREBP has been described as an LXR target, the interaction of LXR and TRbeta in ChREBP regulation was assayed both in vitro and in vivo. Each receptor recognizes a different response element on the ChREBP promoter, located only eight base pairs apart.There is a crosstalk between LXR and TRbeta signalling on the ChREBP promoter in liver but not in WAT where LXR does not regulate ChREBP expression. The molecular basis for this crosstalk has been determined in in vitro systems
Patterns in microbial diversity in North Sea sediments; correlations with specific sediment characteristics and heavy metal pollution
Sauropod trackway patterns expression of special behaviour related to substrate consistency? An example from the Late Jurassic of northwestern Switzerland
Impact of phytoplankton bloom deposition on microbial communities and metal fluxes in contaminated North Sea sediments: A microcosm study
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