Chaotic dynamics of two-dimensional flows around a cylinder

We study flow around a cylinder from a dynamics perspective, using drag and lift as indicators. We observe that the mean drag coefficient bifurcates from the steady case when the Karman vortex street emerges. We also find a jump in the dimension of the drag/lift attractor just above Reynolds number 100. We compare the simulated drag values with experimental data obtained over the last hundred years. Our simulations suggest that a vibrational resonance in the cylinder would be unlikely for Reynolds numbers greater than 1000, where the drag/lift behavior is fully chaotic.Comment: 27 pages, including appendi

Faecal sludge in Accra, Ghana: problems of urban provision

Urban on-site sanitation services present challenges for emptying, transporting, disposing and treating faecal waste. Transfer stations can be used by household-level emptiers to safely dispose of faecal sludge, but they rarely exist. Accra‟s use of transfer stations has provided an opportunity to research their functioning, as part of broader faecal sludge management arrangements. The paper discusses the benefits offered by use of transfer stations, as well as reasons currently limiting their operation. While costs associated with operating and emptying these stations are passed to householders, an illegal sector thrives offering lower cost emptying services, typically with disposal of faecal sludge directly into the environment. At present, bucket latrines offer sanitation services to low-income households unable to afford higher service levels, such as septic tanks. The local government aims to phase-out all bucket latrines by 2010, but affordable alternatives have not been found. Where limited access to land inhibits investment in permanent facilities, families may abandon household sanitation altogether. The paper concludes that correct use of transfer stations can provide improvements for existing faecal sludge management and reduce indiscriminate dumping. They must be made available to all workers, through effective public-private arrangements for ownership and operation

Ode to positive constructive daydreaming

Nearly 60 years ago, Jerome L. Singer launched a groundbreaking research program into daydreaming (Singer, 1955, 1975, 2009) that presaged and laid the foundation for virtually every major strand of mind wandering research active today (Antrobus, 1999; Klinger, 1999, 2009). Here we review Singer’s enormous contribution to the field, which includes insights, methodologies, and tools still in use today, and trace his enduring legacy as revealed in the recent proliferation of mind wandering studies. We then turn to the central theme in Singer’s work, the adaptive nature of positive constructive daydreaming, which was a revolutionary idea when Singer began his work in the 1950s and remains underreported today. Last, we propose a new approach to answering the enduring question: Why does mind wandering persist and occupy so much of our time, as much as 50% of our waking time according to some estimates, if it is as costly as most studies suggest

Faecal sludge management in Accra, Ghana: strengthening links in the chain

Achieving a fully operational Faecal Sludge Management (FSM) chain requires well managed and sustainable services in all aspects of the collection (emptying), transport (haulage), disposal and treatment of faecal sludge. A fully operational FSM chain offers one type of sustainable sanitation system, particularly for urban populations in low and middle-income countries. Failure to ensure all links in the chain are strong and working effectively results in untreated faecal sludge contaminating the environment, with serious implications for human health and environmental degradation. Research in Accra, Ghana has identified important constraints to achieving an efficient and fully functioning FSM chain, with consequences for both people and the environment. Opportunities to improve the institutional and operating environment are identified, particularly affecting engagement between the public and private sector and civil society. Improved stakeholder engagement, together with better regulation, management and access to facilities, enhances services in a way that bring wider benefits to all

Managing Multiple Vital Rates To Maximize Greater Sage Grouse Population Growth

Despite decades of greater sage grouse (Centrocercus urophasianus) field research, the resulting range-wide demographic data has yet to be synthesized into sensitivity analyses to guide management actions. We summarized range-wide demographic rates from 71 studies from 1938-2008 to better understand greater sage-grouse population dynamics. We used data from 38 of these studies with suitable data to parameterize a two-stage, female-based population matrix model. We conducted analytical sensitivity, elasticity, and variancestabilized sensitivity analyses to identify the contribution of each vital rate to population growth rate (?) and life-stage simulation analysis (LSA) to determine the proportion of variation in ? accounted for by each vital rate. Greater sage grouse showed marked annual and geographic variation in multiple vital rates. Sensitivity analyses suggest that, in contrast to most other North American galliforms, female survival is as important for population growth as chick survival and more important than nest success. In lieu of quantitative data on factors driving local populations, we recommend that management efforts for sage grouse focus on increasing juvenile, yearling, and adult female survival by restoring intact sagebrush landscapes, reducing persistent sources of mortality, and eliminating anthropogenic habitat features that subsidize predators. Our analysis also supports efforts to increase chick survival and nest success by managing shrub, forb, and grass cover and height to meet published brood-rearing and nesting habitat guidelines, but not at the expense of reducing shrub cover and height below that required for survival in fall and winter

Draft Genome Sequence of the Caffeine-Degrading Methylotroph Methylorubrum populi Pinkel.

A pink-pigmented facultative methylotroph, Methylorubrum populi Pinkel, was isolated from compost by selective enrichment with caffeine (3,5,7-trimethylxanthine) as the sole carbon, nitrogen, and energy source. We report here its high-quality draft genome sequence, assembled in 35 contigs totaling 5,630,907 bp. We identified 5,681 protein-coding sequences, including those putatively involved in caffeine degradation

Healing relationships and the existential philosophy of Martin Buber

The dominant unspoken philosophical basis of medical care in the United States is a form of Cartesian reductionism that views the body as a machine and medical professionals as technicians whose job is to repair that machine. The purpose of this paper is to advocate for an alternative philosophy of medicine based on the concept of healing relationships between clinicians and patients. This is accomplished first by exploring the ethical and philosophical work of Pellegrino and Thomasma and then by connecting Martin Buber's philosophical work on the nature of relationships to an empirically derived model of the medical healing relationship. The Healing Relationship Model was developed by the authors through qualitative analysis of interviews of physicians and patients. Clinician-patient healing relationships are a special form of what Buber calls I-Thou relationships, characterized by dialog and mutuality, but a mutuality limited by the inherent asymmetry of the clinician-patient relationship. The Healing Relationship Model identifies three processes necessary for such relationships to develop and be sustained: Valuing, Appreciating Power and Abiding. We explore in detail how these processes, as well as other components of the model resonate with Buber's concepts of I-Thou and I-It relationships. The resulting combined conceptual model illuminates the wholeness underlying the dual roles of clinicians as healers and providers of technical biomedicine. On the basis of our analysis, we argue that health care should be focused on healing, with I-Thou relationships at its core