Connectivity for bridge-addable monotone graph classes

A class A of labelled graphs is bridge-addable if for all graphs G in A and all vertices u and v in distinct connected components of G, the graph obtained by adding an edge between u and u is also in A; the class A is monotone if for all G in A and all subgraphs H of G, H is also in A. We show that for any bridge-addable, monotone class A whose elements have vertex set 1,...,n, the probability that a uniformly random element of A is connected is at least (1-o_n(1)) e^{-1/2}, where o_n(1) tends to zero as n tends to infinity. This establishes the special case of a conjecture of McDiarmid, Steger and Welsh when the condition of monotonicity is added. This result has also been obtained independently by Kang and Panagiotiou (2011).Comment: 11 page

Acoustic behavior, poaching risk, and habitat use in African forest elephants (Loxodonta cyclotis): Insights from passive acoustic monitoring

The African forest elephant (Loxodonta cyclotis) is a critically endangered and cryptic species that inhabits the rainforests of Central Africa. Forest elephant populations are severely threatened by poaching for the ivory trade, and an improved understanding of forest elephant behavior and habitat use, and of the anthropogenic pressures that threaten their existence, is essential for conservation of the species. However, their remote tropical rainforest habitat poses logistical constraints on research and makes forest elephants very difficult to observe and study visually. Limited data collection methods have also inhibited our ability to understand the determinants of poaching activity that is driving forest elephants toward extinction. This dissertation addresses forest elephant behavior, ecology, and conservation questions that span multiple scales by capitalizing on the advantages of passive acoustic monitoring (PAM) to detect elephant vocalizations and gunshots. At the finest scale, Chapter 1 examines forest elephant vocal repertoire use at a forest clearing in the Central African Republic and discusses implications for PAM. The different vocalization types of the repertoire varied in the generality or specificity by which they were used by certain age-sex classes of elephants. An understanding of these patterns is important for PAM of forest elephants, as they determine the population (or subset) that is detected and sampled. At the intermediate scale, Chapter 2 examines forest elephant landscape-scale response to individual poaching events detected in a PAM study system. Elephants within 10 km of gunfire events responded to poacher presence (before gunshots were fired) and to gunshots themselves, exhibiting behavioral changes in either vocal activity, site usage, or both. These results suggest that, in addition to the outright killing of targeted individuals, poaching activity affects the general population of elephants across the landscape. At the broadest scale, Chapters 3 and 4 used detections of elephant vocalizations and gunshots to analyze the distributions of forest elephants and poaching events across a 50-sensor PAM grid spanning 1250 sq. km of rainforest in Republic of Congo, for a period of over 3 years. To elucidate the determinants of these distributions, elephant and gunshot detection data were combined with habitat and landscape variables quantified using satellite remote sensing. In Chapter 3, variation in poaching risk depended primarily on factors related to poacher accessibility, such as distance to major rivers and logging roads. These results can guide the allocation of anti-poaching patrol effort to cover high-risk areas at times of increased vulnerability. Chapter 4 examined the habitat resources and anthropogenic pressures (e.g., poaching and logging) that influence forest elephants’ use of the landscape. Elephant occurrence probabilities decreased over the 3 years of the study and were seasonally dependent, increasing in the wet season. Ongoing logging activity deterred forest elephants from using nearby sites, but previously logged areas provided important habitat resources. By leveraging remote sensing methods to expand the scale and resolution of data collection, this dissertation aimed to advance our understanding of forest elephant behavior and ecology, and confronted questions that will improve conservation efforts to protect the species from extinction

The problem of deficiency indices for discrete Schr\"odinger operators on locally finite graphs

The number of self-adjoint extensions of a symmetric operator acting on a complex Hilbert space is characterized by its deficiency indices. Given a locally finite unoriented simple tree, we prove that the deficiency indices of any discrete Schr\"odinger operator are either null or infinite. We also prove that almost surely, there is a tree such that all discrete Schr\"odinger operators are essentially self-adjoint. Furthermore, we provide several criteria of essential self-adjointness. We also adress some importance to the case of the adjacency matrix and conjecture that, given a locally finite unoriented simple graph, its the deficiency indices are either null or infinite. Besides that, we consider some generalizations of trees and weighted graphs.Comment: Typos corrected. References and ToC added. Paper slightly reorganized. Section 3.2, about the diagonalization has been much improved. The older section about the stability of the deficiency indices in now in appendix. To appear in Journal of Mathematical Physic

Convergence of spectra of graph-like thin manifolds

We consider a family of compact manifolds which shrinks with respect to an appropriate parameter to a graph. The main result is that the spectrum of the Laplace-Beltrami operator converges to the spectrum of the (differential) Laplacian on the graph with Kirchhoff boundary conditions at the vertices. On the other hand, if the the shrinking at the vertex parts of the manifold is sufficiently slower comparing to that of the edge parts, the limiting spectrum corresponds to decoupled edges with Dirichlet boundary conditions at the endpoints. At the borderline between the two regimes we have a third possibility when the limiting spectrum can be described by a nontrivial coupling at the vertices.Comment: 38 pages, 6 figures (small changes, Sec 9 extended

Recombinant human epoetin beta in the treatment of chemotherapy-related anemia

Anemia is a common complication of systemic anti-cancer treatment. In this context epoetin beta, like other erythropoiesis-stimulating agents (ESAs), has demonstrable efficacy in raising Hb concentration and reducing the requirement for red cell transfusion. Consequently ESA therapy has gained increasing prominence in the management of chemotherapy-related anemia. However, recent trial data have suggested a higher rate of thromboembolic events, enhanced tumor progression and reduced survival in some patients with cancer who receive ESA therapy. In response, regulatory authorities have mandated increasingly restrictive label changes. In light of these new developments we consider the current role of epoetin beta in the management of chemotherapy-related anemia

Micromanipulation of InP lasers with optoelectronic tweezers for integration on a photonic platform

The integration of light sources on a photonic platform is a key aspect of the fabrication of self-contained photonic circuits with a small footprint that does not have a definitive solution yet. Several approaches are being actively researched for this purpose. In this work we propose optoelectronic tweezers for the manipulation and integration of light sources on a photonic platform and report the positional and angular accuracy of the micromanipulation of standard Fabry-Pérot InP semiconductor laser die. These lasers are over three orders of magnitude bigger in volume than any previously assembled with optofluidic techniques and the fact that they are industry standard lasers makes them significantly more useful than previously assembled microdisk lasers. We measure the accuracy to be 2.5 ± 1.4 µm and 1.4 ± 0.4° and conclude that optoelectronic tweezers are a promising technique for the micromanipulation and integration of optoelectronic components in general and semiconductor lasers in particular

Occupational Therapy Students’ and Graduates’ Perspectives of Traditional and Nontraditional Level I Fieldwork Experiences

Among occupational therapy students and recently graduated practitioners, what are the perceptions of Level I fieldwork in understanding the role of an occupational therapist, application to didactic coursework, and impact on overall skills? Quantitative findings suggest that students and graduates perceived traditional Level I FW settings to be the most effective for understanding the role of an OT, application to didactic coursework, and impact on overall skills in comparison to respondents who experienced non-traditional Level I fieldwork settings. Qualitative data supports this finding as the most common theme reported was participants\u27 desire to work alongside an OT during fieldwork, as required in traditional fieldwork settings. Additionally, participants found FW to be most effective when given the opportunity to be hands-on with clients.These findings can help inform OT to meet ACOTE standards. Future research should focus on investigating FW educator and coordinator perspectives on traditional and nontraditional FW and compare the difference in perspectives between students and educators. This will help determine if there is a disconnect or misunderstanding between stakeholder groups in OT FW education