Comments on Inan’s Notions of Objectual and Propositional Curiosity

In this paper I comment on Inan’s notions of propositional and objectual curiosity. Even though Inan offers an interesting and intuitive distinction between propositional and objectual curiosity, I want to question two aspects of his theory of curiosity. One aspect concerns his thesis that propositional curiosity is interdependent on epistemic attitudes such as belief, certainty and interest. Another aspect of his theory that I discuss is his thesis that objectual curiosity is not reducible to propositional curiosity. In more detail, in the fi rst part, I start off by explaining what propositional curiosity is according to Inan and I bring up two worries that I call: (i) over-complexity as a result of subjectivity and (ii) overcomplexity as a result of dynamics for the above mentioned epistemic attitudes. Both worries stress the problem of over-complexity of Inan’s theory of propositional curiosity. In the second part, I argue that objectual curiosity is, contrary to Inan’s hypothesis, reducible to propositional curiosity. I further argue that the object of wh- questions that, according to Inan, express objectual curiosity can either be about the truth value of general or singular proposition. In addition, I suggest that only the reading where wh- questions express curiosity in a form of de re reading and have a singular proposition as their content is the one that is compatible with Inan’s notion of objectual curiosity

mRNA localization, reaction centre biogenesis and thylakoid membrane targeting in cyanobacteria

The thylakoid membranes of cyanobacteria form a complex intracellular membrane system with a distinctive proteome. The sites of biogenesis of thylakoid proteins remain uncertain, as do the signals that direct thylakoid membrane-integral proteins to the thylakoids rather than to the plasma membrane. Here, we address these questions by using fluorescence in situ hybridization to probe the subcellular location of messenger RNA molecules encoding core subunits of the photosystems in two cyanobacterial species. These mRNAs cluster at thylakoid surfaces mainly adjacent to the central cytoplasm and the nucleoid, in contrast to mRNAs encoding proteins with other locations. Ribosome association influences the distribution of the photosynthetic mRNAs on the thylakoid surface, but thylakoid affinity is retained in the absence of ribosome association. However, thylakoid association is disrupted in a mutant lacking two mRNA-binding proteins, which probably play roles in targeting photosynthetic proteins to the thylakoid membrane

Transport of Folded Proteins by the Tat System

The twin-arginine protein translocation (Tat) system has been characterized in bacteria, archaea and the chloroplast thylakoidal membrane. This system is distinct from other protein transport systems with respect to two key features. Firstly, it accepts cargo proteins with an N-terminal signal peptide that carries the canonical twin-arginine motif, which is essential for transport. Second, the Tat system only accepts and translocates fully folded cargo proteins across the respective membrane. Here, we review the core essential features of folded protein transport via the bacterial Tat system, using the three-component TatABC system of Escherichia coli and the two-component TatAC systems of Bacillus subtilis as the main examples. In particular, we address features of twin-arginine signal peptides, the essential Tat components and how they assemble into different complexes, mechanistic features and energetics of Tat-dependent protein translocation, cytoplasmic chaperoning of Tat cargo proteins, and the remarkable proofreading capabilities of the Tat system. In doing so, we present the current state of our understanding of Tat-dependent protein translocation across biological membranes, which may serve as a lead for future investigations

TESTING STABILITY WITHOUT PENDULUMS: A FEASIBILITY ANALYSIS

Current International Maritime Organization (IMO) and U.S. Coast Guard regulations require inclining tests of vessels to use three heel-measuring devices, one of which must be a pendulum. This is a problem since pendulums are required to be at least 10 feet in height and newer vessel designs are constrained by overhead clearance and deck space. To investigate this problem, this thesis examines five different stability test results that were submitted to the U.S. Coast Guard Marine Safety Center (MSC). The author identified and inputted random error into the independent variables used to calculate each vessel’s metacentric height (GM). The independent variables were then used in a Design of Experiment (DOE) to examine which factors had the strongest effect on GM. Of the factors analyzed, the device used to measure heel angle proved to be the most significant. The author then constructed three different miniature models to conduct inclining experiments in a controlled environment. The heel-measuring devices used during these experiments were a smartphone and pendulum. In all three miniature model experiments, the smartphone demonstrated better precision over the pendulum. This thesis recommends keeping current standards and regulations intact until further data and research are gathered.http://archive.org/details/testingstability1094559662Lieutenant, United States Coast GuardApproved for public release; distribution is unlimited