955 research outputs found
The practice of teachers reading aloud in the classroom
Thesis (M.Ed.) University of Alaska Fairbanks, 2014This inquiry, which involved use of a teacher survey and classroom observations, was designed to explore how teachers use the practice of reading aloud. This small case study, of one urban elementary school in Alaska, also set out to examine how teachers view the practice of a read-aloud. Studies have identified a number of effective components of a read-aloud. This study found teachers in agreement on some important reasons to read aloud and the components of a read-aloud that they value. The teachers in my inquiry appear to value reading aloud and they all share similarities in how they use the read-aloud practice. All of the teachers agreed that the three most important reasons to read aloud are: for enjoyment, to expose students to texts that they may not read otherwise, and to promote a love of literature and/or reading. Most of the teachers rated two components in particular as very important: animation and expression, and modeling fluent reading
Spin-1/2 Bosonization on Compact Surfaces
We extend an existing Bose-Fermi equivalence formula to two-dimensional Euclidean space-times with arbitrary compact topology. The result relates the nonchiral Dirac partition function to that of a scalar field, times a theta function. The proof is a short application of methods from complex geometry and Quillen\u27s determinant constructions
Response of male \u3ci\u3eCentruroides vittatus\u3c/i\u3e (Scorpiones: Buthidae) to aerial and substrate-borne chemical signals
Chemical signaling promotes mate location throughout numerous animal taxa. In this study we investigated the possibility that striped scorpions, Centruroides vittatus, use chemical signaling in the form of odor plumes or substrate-borne deposits as communication channels. A Y-shaped arena was constructed to test scorpions’ use of air-borne chemical cues in the detection of potential mates. A second, circular behavioral choice chamber was used to test male scorpions’ responses to female deposits by direct substrate contact. Male scorpions showed no tendency to move toward the female in tests of air-borne chemical transmission but they did demonstrate behavior associated with chemical detection when exposed to substrate-borne feminine deposits. Our experiments do not provide evidence that male C. vittatus use aerial pheromones to locate female scorpions but that they are highly sensitive to direct contact of substrate-borne chemical deposits
Drivers of intertidal oyster reef and tidal creek accretion over the last century
Salt marshes and intertidal oyster reefs provide valuable ecosystem services but are being lost or altered due to human modifications at the coast. Restoration projects intend to recover ecosystem services, but little is known about the conditions that promote longevity in restoration projects which requires vertical accretion to keep pace with sea-level rise. Furthermore, while there is documentation of the impacts of land-use change on sediment loads in large river systems and sedimentation in estuaries, small coastal tidal creeks have been largely ignored. To address these issues, this work 1. Quantified intertidal oyster reef growth and identified optimal restoration settings across tidal ranges, atmospheric temperatures, and landscape settings, 2. Evaluated land-use change since 1950 CE and associated impacts on tidal creek sedimentation, and 3. Determined how land-use changes affected sediment and carbon accumulation rates of saltmarshes. Chapter one compared the growth of 12 natural intertidal oyster reefs of varying age across two tidal ranges and landscape settings in coastal North Carolina. Peak growth rates were similar among landscape and tidal settings, but flow baffling associated with fringing reefs and higher summer air temperatures contributed to a lower position of the optimal growth zone in the tidal frame. Chapters 2 and 3 were addressed by comparing sediment accumulation rates before and after a land-use change in 12 tidal creeks across two distinct regions in North Carolina, one region of low relief tidal-creek watersheds where land-use change was dominated by fluctuations in forest, silviculture, and agriculture, and another region of high relief tidal-creek watersheds where land-use change was dominated by suburban development. While accumulation rates accelerated within the creek bottom and adjacent fringing marsh sites after a land-use change, the magnitude of the acceleration differed depending on the morphology of the creek basin. There was faster acceleration in accumulation rates at creek sites within coastal prism incised valleys, but slower acceleration for their adjacent fringing salt marshes. Results from this work will provide guidance for oyster reef restoration and coastal watershed management for sedimentation in tidal creeks and salt marshes.Doctor of Philosoph
Probably Safe or Live
This paper presents a formal characterisation of safety and liveness
properties \`a la Alpern and Schneider for fully probabilistic systems. As for
the classical setting, it is established that any (probabilistic tree) property
is equivalent to a conjunction of a safety and liveness property. A simple
algorithm is provided to obtain such property decomposition for flat
probabilistic CTL (PCTL). A safe fragment of PCTL is identified that provides a
sound and complete characterisation of safety properties. For liveness
properties, we provide two PCTL fragments, a sound and a complete one. We show
that safety properties only have finite counterexamples, whereas liveness
properties have none. We compare our characterisation for qualitative
properties with the one for branching time properties by Manolios and Trefler,
and present sound and complete PCTL fragments for characterising the notions of
strong safety and absolute liveness coined by Sistla
Partially ordered distributed computations on asynchronous point-to-point networks
Asynchronous executions of a distributed algorithm differ from each other due
to the nondeterminism in the order in which the messages exchanged are handled.
In many situations of interest, the asynchronous executions induced by
restricting nondeterminism are more efficient, in an application-specific
sense, than the others. In this work, we define partially ordered executions of
a distributed algorithm as the executions satisfying some restricted orders of
their actions in two different frameworks, those of the so-called event- and
pulse-driven computations. The aim of these restrictions is to characterize
asynchronous executions that are likely to be more efficient for some important
classes of applications. Also, an asynchronous algorithm that ensures the
occurrence of partially ordered executions is given for each case. Two of the
applications that we believe may benefit from the restricted nondeterminism are
backtrack search, in the event-driven case, and iterative algorithms for
systems of linear equations, in the pulse-driven case
Chronic traumatic encephalopathy in contact sports: A systematic review of all reported pathological cases
© 2015 Maroon et al. Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with head trauma. Although initially believed to affect only boxers, the at-risk population has expanded to encompass a much wider demographic, including American football players, hockey players, wrestlers, and military veterans. This expansion has garnered considerable media attention and public concern for the potential neurodegenerative effects of head trauma. The main aim of this systematic review is to give a complete overview of the common findings and risk factors for CTE as well as the status quo regarding the incidence and prevalence of CTE. This systematic review was performed using PubMed and MEDLINE and includes all neuropathologically confirmed cases of CTE in the medical literature to date, from the first published case in 1954 to August 1, 2013 (n = 153). The demographics, including the primary source of mTBI (mild Traumatic Brain Injury), age and cause of death, ApoE genotype, and history of substance abuse, when listed, were obtained from each case report. The demographics of American football players found to have CTE are also presented separately in order to highlight the most prevalent group of CTE cases reported in recent years. These 153 case reports of CTE represent the largest collection to date. We found that a history of mTBI was the only risk factor consistently associated with CTE. In addition, we found no relationships between CTE and age of death or abnormal ApoE allele. Suicide and the presence of premorbid dementia was not strongly associated with CTE. We conclude that the incidence of CTE remains unknown due to the lack of large, longitudinal studies. Furthermore, the neuropathological and clinical findings related to CTE overlap with many common neurodegenerative diseases. Our review reveals significant limitations of the current CTE case reporting and questions the widespread existence of CTE in contact sports
Cyclotomy and Ramanujan sums in quantum phase locking
Phase-locking governs the phase noise in classical clocks through effects
described in precise mathematical terms. We seek here a quantum counterpart of
these effects by working in a finite Hilbert space. We use a coprimality
condition to define phase-locked quantum states and the corresponding
Pegg-Barnett type phase operator. Cyclotomic symmetries in matrix elements are
revealed and related to Ramanujan sums in the theory of prime numbers. The
employed mathematical procedures also emphasize the isomorphism between
algebraic number theory and the theory of quantum entanglementComment: 6 pages, 3 figures, version accepted at Phys. Lett.
- …