Entropic fluctuations in XY chains and reflectionless Jacobi matrices

We study the entropic fluctuations of a general XY spin chain where initially the left(x0) part of the chain is in thermal equilibrium at inverse temperature Tl/Tr. The temperature differential results in a non-trivial energy/entropy flux across the chain. The Evans-Searles (ES) entropic functional describes fluctuations of the flux observable with respect to the initial state while the Gallavotti-Cohen (GC) functional describes these fluctuations with respect to the steady state (NESS) the chain reaches in the large time limit. We also consider the full counting statistics (FCS) of the energy/entropy flux associated to a repeated measurement protocol, the variational entropic functional (VAR) that arises as the quantization of the variational characterization of the classical Evans-Searles functional and a natural class of entropic functionals that interpolate between FCS and VAR. We compute these functionals in closed form in terms of the scattering data of the Jacobi matrix h canonically associated to the XY chain. We show that all these functionals are identical if and only if h is reflectionless (we call this phenomenon entropic identity). If h is not reflectionless, then the ES and GC functionals remain equal but differ from the FCS, VAR and interpolating functionals. Furthermore, in the non-reflectionless case, the ES/GC functional does not vanish at 1 (i.e., the Kawasaki identity fails) and does not have the celebrated ES/GC symmetry. The FCS, VAR and interpolating functionals always have this symmetry. In the cases where h is a Schr\"odinger operator, the entropic identity leads to some unexpected open problems in the spectral theory of one-dimensional discrete Schr\"odinger operators

Modeling the Impact of the Payload Alert Communications System (PACS) on the Accuracy of Conjunction Analysis

The Air Force Institute of Technology (AFIT) and the Air Force Research Laboratory (AFRL) are jointly developing a system known as the Payload Alert Communications System (PACS) whose purpose is to decrease the statistical uncertainty in the location of resident space objects (RSOs). PACS is designed to augment the Joint Space Operations Center\u27s (JSpOC) existing space object tracking capabilities which is expected to increase the accuracy of conjunction estimation. In the current PACS design, a small payload would be attached to certain RSOs prior their launch. It is envisioned that this payload would basically consist of a microcontroller, a Global Positioning System (GPS) receiver, a communication transceiver, and a power source. Once on orbit, the PACS payload would collect GPS position information and then periodically, or upon demand, transmit the orbital information back to JSpOC. In this thesis, a study is performed to determine how the accuracy of conjunction analysis performed by the JSpOC would be impacted when RSOs are equipped with PACS. This effort requires the development an initial PACS system architecture, formulation of the mathematical models used in conjunction analysis, and the simulation and analysis of conjunction analysis under various scenarios

The Potential Applications of Tooth Cement Increment Analysis in Historical Archaeology

The study of incremental structures in animal teeth is an analytical technique that is receiving increased attention from zooarchaeologists working in many parts of the world. The seasonal and annual cycles in the formation of tooth increments makes them ideal for determining the age of an animal when it was killed and the season of its death. This type of information can contribute significantly to interpretations of past animal husbandry practices. A sample of eight domestic animal teeth from the Wilkinson Backlot Site in dowtown Boston, Massachusetts, were studied in this fashion. Microscopic examination of the increment pattern of the cement on the roots of the teeth allowed age and season of death to be estimated. The results suggest that this analytical technique has a great deal of promise for the analysis of historical faunal assemblages, particularly for determining seasonal patterns in animal slaughtering

Interpreting Social Organization at Industrial Sites: An Example from the Ohio Trap Rock Mine

Historical archaeologists have frequently tried to interpret aspects of the social organization of production from artifacts at industrial sites. These studies have encompassed a variety of issues: the role of skilled immigrants, the effects of de-skilling work, and the ways workers resisted work discipline or used material culture to express their autonomy. Some recent studies protray the organization of production and the forces of industrialization as the overarching determinants of domestic assemblage pattering, while other studies emphasize factors such as household composition, household lifecycle, and the gender organization of labor. This paper reviews several studies of artifact assemblages from industrial sites, focusing in detail on the Ohio Trap Rock Mine Site. This review suggests both the promise and potential pitfalls of trying to use archaeological materials to understand the organization of industrial communities

Introduction

A brief overview of the publications in this volume. This includes the awards for excellence in service, the winners of the student paper ocmpetition, the paper topics of the volume including use of material culture from a 19th century laborer\u27s home, archaebiology and urban salvage archaeology in downtown Lancaster, Pennsylvania

Risk of uterine rupture with a trial of labor in women with multiple and single prior cesarean delivery.

Journal ArticleOBJECTIVE: To determine whether the risk for uterine rupture is increased in women attempting vaginal birth after multiple cesarean deliveries. METHODS: We conducted a prospective multicenter observational study of women with prior cesarean delivery undergoing trial of labor and elective repeat operation. Maternal and perinatal outcomes were compared among women attempting vaginal birth after multiple cesarean deliveries and those with a single prior cesarean delivery. We also compared outcomes for women with multiple prior cesarean deliveries undergoing trial of labor with those electing repeat cesarean delivery. RESULTS: Uterine rupture occurred in 9 of 975 (0.9%) women with multiple prior cesarean compared with 115 of 16,915 (0.7%) women with a single prior operation (P = .37). Multivariable analysis confirmed that multiple prior cesarean delivery was not associated with an increased risk for uterine rupture. The rates of hysterectomy (0.6% versus 0.2%, P = .023) and transfusion (3.2% versus 1.6%, P < .001) were increased in women with multiple prior cesarean deliveries compared with women with a single prior cesarean delivery attempting trial of labor. Similarly, a composite of maternal morbidity was increased in women with multiple prior cesarean deliveries undergoing trial of labor compared with those having elective repeat cesarean delivery (odds ratio 1.41, 95% confidence interval 1.02-1.93). CONCLUSION: A history of multiple cesarean deliveries is not associated with an increased rate of uterine rupture in women attempting vaginal birth compared with those with a single prior operation. Maternal morbidity is increased with trial of labor after multiple cesarean deliveries, compared with elective repeat cesarean delivery, but the absolute risk for complications is small. Vaginal birth after multiple cesarean deliveries should remain an option for eligible women. LEVEL OF EVIDENCE: II-2

Phase I Archaeological Intensive Survey of Hassanamesitt Woods Property, Grafton, Massachusetts

The Center for Cultural and Environmental History conducted a Phase I archaeological intensive survey of the Hassanamesitt Woods property in Grafton, Massachusetts from October 2004 through January 2005. Documentary evidence has suggested that the property may contain remains of the church for the Praying Indian village of Hassanamisco, established by John Eliot in 1660. Historical deed research has also placed several Nipmuc families on the property in the early 18th century, suggesting the area was resettled by the original inhabitants of Hassanimisco in the aftermath of King Philip\u27s War. Throughout the course of the 18th and 19th centuries the property was subsequently parceled out for agricultural purposes to white landowners. Nipmuc presence on the property however endured until the end of the 19th century. During the 20th century the property was utilized predominantly for orchards before reverting to its current state of woodland. The survey of the 203+ acre property on the southern slope of Keith Hill consisted of shovel testing and a GPS survey of above ground features in order to identify historic and prehistoric resources and make recommendations for the future management of the property. A total of 386 test pits were excavated on 10m and 20m intervals covering approximately 74 acres and identifying six historic sites and one prehistoric site. The prehistoric site is composed of a well-defined lithic quarry, while the historic sites consist of the remains of 18th, 19th, and 20th century residential, agricultural, and low level industrial activities. The highest concentration of residential material has been identified as the remains of 18th and 19th century Nipmuc settlement. No 17th century component related to John Eliot\u27s church or meeting house was recovered. Several aboveground features were located, including cellar holes, wens, extensive stone walls, stone retaining walls, and cobbled terraces. Because the property is not slated for large-scale development it is recommended that no further immediate archaeological testing is needed. However, the archaeological remains related to 18th and 19th century Nipmuc settlement offer an opportunity to investigate Native American resettlement after the abandonment of Hassanamisco. Future archaeology may also help with public interpretation of the property within the context of long term land use from the Prehistoric Archaic period through the Early Modem period. Data gathered during this Phase I survey provides a starting point for the public interpretation of the Hassanamesitt Woods property and allows for the proper management of the property in terms of trail placement and low impact construction