Limits on the Observable Dynamics of Mixed States

It is shown that the observability of a large class of operations on mixed states is fundamentally limited. We consider trace preserving, unital operations. This class includes unitary and perfect premeasurement operations. An upper bound on the trace distance between an untransformed state and a state transformed by one of these operations is derived. The bound is dependent only on the purity of the state. In the case of maximal mixedness, the bound implies all operations of this class are unobservable.Comment: 7 pages, accepted for publication in PR

A comprehensive theory of induction and abstraction, part II

This is part II in a series of papers outlining Abstraction Theory, a theory that I propose provides a solution to the characterisation or epistemological problem of induction. Logic is built from first principles severed from language such that there is one universal logic independent of specific logical languages. A theory of (non-linguistic) meaning is developed which provides the basis for the dissolution of the `grue' problem and problems of the non-uniqueness of probabilities in inductive logics. The problem of counterfactual conditionals is generalised to a problem of truth conditions of hypotheses and this general problem is then solved by the notion of abstractions. The probability calculus is developed with examples given. In future parts of the series the full decision theory is developed and its properties explored

A comprehensive theory of induction and abstraction, part I

I present a solution to the epistemological or characterisation problem of induction. In part I, Bayesian Confirmation Theory (BCT) is discussed as a good contender for such a solution but with a fundamental explanatory gap (along with other well discussed problems); useful assigned probabilities like priors require substantive degrees of belief about the world. I assert that one does not have such substantive information about the world. Consequently, an explanation is needed for how one can be licensed to act as if one has substantive information about the world when one does not. I sketch the outlines of a solution in part I, showing how it differs from others, with full details to follow in subsequent parts. The solution is pragmatic in sentiment (though differs in specifics to arguments from, for example, William James); the conceptions we use to guide our actions are and should be at least partly determined by preferences. This is cashed out in a reformulation of decision theory motivated by a non-reductive formulation of hypotheses and logic. A distinction emerges between initial assumptions--that can be non-dogmatic--and effective assumptions that can simultaneously be substantive. An explanation is provided for the plausibility arguments used to explain assigned probabilities in BCT. In subsequent parts, logic is constructed from principles independent of language and mind. In particular, propositions are defined to not have form. Probabilities are logical and uniquely determined by assumptions. The problems considered fatal to logical probabilities--Goodman's `grue' problem and the uniqueness of priors problem are dissolved due to the particular formulation of logic used. Other problems such as the zero-prior problem are also solved. A universal theory of (non-linguistic) meaning is developed. Problems with counterfactual conditionals are solved by developing concepts of abstractions and corresponding pictures that make up hypotheses. Spaces of hypotheses and the version of Bayes' theorem that utilises them emerge from first principles. Theoretical virtues for hypotheses emerge from the theory. Explanatory force is explicated. The significance of effective assumptions is partly determined by combinatoric factors relating to the structure of hypotheses. I conjecture that this is the origin of simplicity

Teaching Pronunciation As A Core Skill Using The Silent Way Approach

These materials were developed as part of an exploration of how to interweave the study of pronunciation together with the study of the meaning and structure of the language in a way that makes pronunciation practice a central, present, and prominent part of every lesson. Within the framework of teaching pronunciation with the materials, techniques, and principles of the Silent Way Approach, the focus was placed on creating activities that would (1) help students to notice and practice the essential pronunciation elements of the language, known in the Silent Way as the ‘melody’ (i.e., intonation, stress, phrasing, rhythm, etc.), (2) to accurately produce individual sounds on a word level, and (3) to develop an inner criteria for what is intelligible

Success in Housing: How Much Does Criminal Background Matter?

Using data from the Research Collaborative organizations, Wilder Research conducted a quantitative analysis that looked at the relationship between a resident's housing outcomes and their criminal background

The good, the bad, and the tiny : a simple, mechanistic-probabilistic model of virus-nutrient colimitation in microbes

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 10 (2015): e0143299, doi:10.1371/journal.pone.0143299.For phytoplankton and other microbes, nutrient receptors are often the passages through which viruses invade. This presents a bottom-up vs. top-down, co-limitation scenario; how do these would-be-hosts balance minimizing viral susceptibility with maximizing uptake of limiting nutrient(s)? This question has been addressed in the biological literature on evolutionary timescales for populations, but a shorter timescale, mechanistic perspective is lacking, and marine viral literature suggests the strong influence of additional factors, e.g. host size; while the literature on both nutrient uptake and host-virus interactions is expansive, their intersection, of ubiquitous relevance to marine environments, is understudied. I present a simple, mechanistic model from first principles to analyze the effect of this co-limitation scenario on individual growth, which suggests that in environments with high risk of viral invasion or spatial/temporal heterogeneity, an individual host’s growth rate may be optimized with respect to receptor coverage, producing top-down selective pressure on short timescales. The model has general applicability, is suggestive of hypotheses for empirical exploration, and can be extended to theoretical studies of more complex behaviors and systems.This work was supported by the Massachusetts Institute of Technology Charles Vest Presidential Fellowship

Vacuum Tumbling for the Incorporation of Phosphates in Gulf Shrimp.

A processing method for shrimp in the Gulf of Mexico region is to place mechanically peeled shrimp in plastic bags in a retail box and add a mixture of water, sodium chloride, and sodium tripolyphosphate (STPP). The box is then placed in frozen storage. As the shrimp and solution freeze, there is a potential for the shrimp to absorb solution inconsistently. When used properly, phosphates help to retain natural moisture, and protect the product through freezing and thawing. However, excessive absorption of phosphate solution can lead to a loss of functional benefits in the finished product. When thawed, the over-treated product has a glassine appearance, soft texture, and occasional soapy taste. The product resists natural changes during cooking, such as development of pink color and coagulation of protein. Some local processors consider this the industry standard, while others have a desire to produce a higher quality product line. The objective of this study was to determine the potential of a vacuum tumbling method for application of condensed phosphate solutions to produce a value-added, wild-caught, Louisiana Gulf shrimp product. Shrimp containing no added phosphates from Louisiana, Honduras, South Carolina, and Texas were obtained, peeled, and deveined. Shrimp, plus solutions containing sodium tripolyphosphate (STPP) and sodium acid pyrophosphate (SAPP), were added to a clear tumbling chamber and tumbled under 22 mm Hg vacuum until no free solution was visible. Treated shrimp were compared for moisture content in raw and cooked products, cook-cool loss, and changes in protein content and microstructure after freeze thaw. Standardization of the uptake data showed that there was a consistent level of uptake using the SAPP blend. Standardized cook-cool data indicated that the STPP treatment had equal cook-cool loss values compared to the control. The tumbled shrimp also had reduced protein solubilization. The measurement of muscle fiber area showed that it is difficult to determine a relationship between fiber area to level of moisture or uptake in the finished product. This study has shown promising initial results for improvements in value-added shrimp using vacuum tumbling. Scale-up studies should be performed to determine its feasibility on an industrial scale