Field guide for didymo DNA sample collection

This protocol is designed for work in two-person teams for both safety and to maximise sample integrity

Models of free quantum field theories on curved backgrounds

Free quantum field theories on curved backgrounds are discussed via three explicit examples: the real scalar field, the Dirac field and the Proca field. The first step consists of outlining the main properties of globally hyperbolic spacetimes, that is the class of manifolds on which the classical dynamics of all physically relevant free fields can be written in terms of a Cauchy problem. The set of all smooth solutions of the latter encompasses the dynamically allowed configurations which are used to identify via a suitable pairing a collection of classical observables. As a last step we use such collection to construct a $*$-algebra which encodes the information on the dynamics and on the canonical commutation or anti-commutation relations depending whether the underlying field is a Fermion or a Boson.Comment: 41 page

Fabrication of high-quality-factor photonic crystal microcavities in InAsP/InGaAsP membranes

Optical fiber taper waveguides are used to improve the efficiency of room temperature photoluminescence measurements of AlGaAs microdisk resonant cavities with embedded self-assembled InAs quantum dots. As a near-field collection optic, the fiber taper improves the collection efficiency from microdisk lasers by a factor of ∼15–100 times in comparison to conventional normal incidence free-space collection techniques. In addition, the fiber taper can serve as an efficient means for pumping these devices, and initial measurements employing fiber pumping and collection are presented. Implications of this work towards chip-based cavity quantum electrodynamics experiments are discussed

A spectral-like decomposition for transitive Anosov flows in dimension three

Given a (transitive or non-transitive) Anosov vector field $X$ on a closed three-dimensional manifold $M$, one may try to decompose $(M,X)$ by cutting $M$ along two-tori transverse to $X$. We prove that one can find a finite collection $\{T_1,\dots,T_n\}$ of pairwise disjoint, pairwise non-parallel incompressible tori transverse to $X$, such that the maximal invariant sets $\Lambda_1,\dots,\Lambda_m$ of the connected components $V_1,\dots,V_m$ of $M-(T_1\cup\dots\cup T_n)$ satisfy the following properties: 1, each $\Lambda_i$ is a compact invariant locally maximal transitive set for $X$, 2, the collection $\{\Lambda_1,\dots,\Lambda_m\}$ is canonically attached to the pair $(M,X)$ (i.e., it can be defined independently of the collection of tori $\{T_1,\dots,T_n\}$), 3, the $\Lambda_i$'s are the smallest possible: for every (possibly infinite) collection $\{S_i\}_{i\in I}$ of tori transverse to $X$, the $\Lambda_i$'s are contained in the maximal invariant set of $M-\cup_i S_i$. To a certain extent, the sets $\Lambda_1,\dots,\Lambda_m$ are analogs (for Anosov vector field in dimension 3) of the basic pieces which appear in the spectral decomposition of a non-transitive axiom A vector field. Then we discuss the uniqueness of such a decomposition: we prove that the pieces of the decomposition $V_1,\dots,V_m$, equipped with the restriction of the Anosov vector field $X$, are "almost unique up to topological equivalence".Comment: 22 pages, 4 figure

Photoluminescence measurements of quantum-dot-containing semiconductor microdisk resonators using optical fiber taper waveguides

Fiber taper waveguides are used to improve the efficiency of room temperature photoluminescence measurements of AlGaAs microdisk resonant cavities with embedded self-assembled InAs quantum dots. As a near-field collection optic, the fiber taper improves the collection efficiency from microdisk lasers by a factor of ~ 15-100 times in comparison to conventional normal incidence free-space collection techniques. In addition, the fiber taper can serve as a efficient means for pumping these devices, and initial measurements employing fiber pumping and collection are presented. Implications of this work towards chip-based cavity quantum electrodynamics experiments are discussed.Comment: 10 pages, 7 figure

Assessing Descriptive Substance in Free-Text Collection-Level Metadata

Collection-level metadata has the potential to provide important information about the features and purpose of individual collections. This paper reports on a content analysis of collection records in an aggregation of cultural heritage collections. The findings show that the free-text Description field often provides more accurate and complete representation of subjects and object types than the specified fields. Properties such as importance, uniqueness, comprehensiveness, provenance, and creator are articulated, as well as other vital contextual information about the intentions of a collector and the value of a collection, as a whole, for scholarly users. The results demonstrate that the semantically rich free-text Description field is essential to understanding the context of collections in large aggregations and can serve as a source of data for enhancing and customizing controlled vocabulariesIMLS NLG Research and Demonstration grant LG-06-07-0020-07published or submitted for publicationis peer reviewe

Heavy Vehicle Performance During Recovery From Forced-Flow Urban Freeway Conditions Due To Incidents, Work Zones and Recurring Congestion

Information contained in the Highway Capacity Manual on the influence heavy vehicles have on freeway traffic operations has been based on few field data collection efforts and relied mostly on traffic simulation efforts. In the 2010 Manual heavy vehicle impact is evaluated based on “passenger car equivalent” values for buses, recreational vehicles and trucks. These values were calibrated for relatively uncongested freeway conditions (levels of service A through C) since inadequate field data on heavy vehicle behavior under congested conditions were available. A number of field data collection efforts, that were not included in deriving the passenger car equivalent values used in the Highway Capacity Manual, indicated that heavy vehicle impacts on traffic operations may increase as freeway congestion levels increase and freeways operate under unstable flow conditions. The goal of the present effort was to collect and analyze field data with an emphasis on heavy vehicle behavior under lower speeds and derive passenger car equivalent values under such conditions