Late Holocene environmental history and tephrostratigraphy in northwestern Costa Rica : a 4000 year record from Lago Cote

Paleoecological studies in the neotropics are revealing changes in past climate regimes and human use of the landscape that were previously unknown. Few paleoecology studies have been conducted in Costa Rica and, in most of these studies, strong evidence of prehistoric human impacts overwhelmed evidence of climate signals. Lago Cote, in the Cordillera de Tilarán, is the largest natural lake in Costa Rica (198 ha). Because of its size, Cote sediments reflect a more regional record of pollen and charcoal accumulation. The sediments also preserve tephra layers from past eruptions of nearby Arenal volcano. In this thesis, I present an environmental history and tephrostratigraphy based on pollen, charcoal, and tephra preserved in a 3.6 m sediment core from Lago Cote. High amounts of grass charcoal and grass pollen from the lower part of the core indicate a drier climate regime with frequent landscape fires from ~4000 to 2600 cal. yr BP. Many or most of these fires were likely of human origin. The occurrence of a maize pollen grain in this zone documents agriculture at ~3900 cal. yr BP. After 2600 cal. yr BP, a dramatic decrease of grass pollen and charcoal reflects wetter conditions that limited landscape fires and agriculture. This climate change occurred simultaneously with an archaeological phase change documented in the nearby Arenal basin by the Proyecto Prehistórico Arenal. Small peaks in pollen of lower montane pollen taxa at the base of this zone may indicate forest regeneration. Comparison of Cote tephra to an earlier tephrochronology at the nearby El Tajo site was not straightforward. Cote tephras, analyzed by X-ray fluorescence, show differences in mineral composition when compared to the more proximal El Tajo tephras, and have lower levels of silicon dioxide than found at El Tajo. Because of major differences in tephra chemistries, visual comparison was a more effective way to compare tephra layers between the sites. Three tephra layers reported from El Tajo are not present in the Cote sediments, including the most recent Arenal eruption in 1968. Two tephra layers in the lower part of the Cote core are not part of the El Tajo tephrochronology, and represent earlier eruptions from Arenal or the nearby and older Chato volcano. In the Cote sediments, peaks in Cecropia pollen follow at least two tephra layers, most likely indicating vegetation regeneration following eruptions of Arenal volcano

Informing the carbon frontier : economics and landscape in the western Amazon

In recent years, forestry carbon offset projects have been on the rise. While praised for their ability to offset emissions inexpensively, these programs are also criticized for their tendency to overlook other important social, environmental and economic processes. This thesis examines the site of a major carbon offset program in the western Amazon of Peru as a case study for multi-objective conservation planning. Using a recently released high resolution carbon dataset, this study first identifies areas of highest above ground carbon density. It then innovates by generating models for two additional conservation measures: forest connectivity and deforestation probability. While the forest connectivity model is informed by landscape ecology and is a more simple modification of least cost path, the deforestation model uses principles of economic rent to produce spatially explicit probabilities. By incorporating concepts of landscape ecology and economic rent, this work presents new models for the study area and adds to the theory surrounding multi-objective conservation planning. It also identifies if, how, and where three distinct conservation criteria can find commonalities. Unsurprisingly, the three criteria result in distinct spatial patterns. When all three are prioritized, less than 3% of the study area qualifies for priority. However, while this analysis highlights the difficulty of simultaneously prioritizing all three criteria, it also offers hope. Landscape-level analyses can help policymakers and conservation practitioners prioritize these limited areas while household-level and broader contextual information can help inform how initiatives are ultimately implemented. Given the limited area under all three criteria, stakeholders can strengthen efforts by encouraging connectivity-enhancing land use practices, incorporating areas where two criteria are met, or further facilitating nearby community involvement. As pressures to marry social, environmental and economic continue, incentive schemes will need to rethink these strategies and innovate, and further research should be conducted.Geography and the Environmen

Arrival to the City

The projects to follow are shamanic acts, trying to heal the eternal wound of existence, of life and architecture. The healing occurs through acts and events which constitute the discourse of arrival to an ideal city

Beyond communication:The role of standardized protocols in a changing health care environment

Background: Communication errors have grave consequences in health care settings. The situationYbackgroundY assessmentYrecommendation (SBAR) protocol has been theorized to improve communication by creating a common language between nurses and physicians in acute care situations. This practice is gaining acceptance across the health care field. However, as yet, there has been little investigation of the ways in which SBAR may have an impact on how health care professionals operate beyond the creation of a common language. Purpose: The purposes of the study were to explore the implementation of the SBAR protocol and investigate the potential impact of SBAR on the day-to-day experiences of nurses. Methods: We performed a qualitative case study of 2 hospitals that were implementing the SBAR protocol. We collected data from 80 semistructured interviews with nurses, nurse manager, and physicians; observation of nursing and other hospital activities; and documents that pertained to the implementation of the SBAR protocol. Data were analyzed using a thematic approach. Findings: Our analysis revealed 4 dimensions of impact that SBAR has beyond its use as a communication tool: schema formation, development of legitimacy, development of social capital, and reinforcement of dominant logics

Professional practice models for nursing: A review of the literature and synthesis of key components

This review aimed to synthesise literature describing the development and/or implementation and/or evaluation of a professional practice model to determine the key model components. A professional practice model depicts nursing values and defines the structures and processes that support nurses to control their own practice and to deliver quality care. A review of English language papers published up to August 2014 identified 51 articles that described 38 professional practice models. Articles were subjected to qualitative analysis to identify the concepts common to all professional practice models. Key elements of professional practice models were theoretical foundation and six common components: leadership; nurses' independent and collaborative practice; environment; nurse development and reward; research/innovation; and patient outcomes. A professional practice model provides the foundations for quality nursing practice. This review is an important resource for nurse leaders who seek to advance their organisation in a journey for excellence through the implementation of a professional practice model. This summary of published professional practice models provides a guide for nurse leaders who seek to develop a professional practice model. The essential elements of a professional practice model; theoretical foundation and six common components, are clearly described. These elements can provide the starting point for nurse leaders' discussions with staff to shape a professional practice model that is meaningful to direct care nurses

Middle to Late Holocene Environmental Change and Human Impacts in Seasonally Dry Neotropical Forest of Northwestern Costa Rica: Sedimentary Evidence from Six Lakes

This dissertation presents evidence of long-term changes in climate, fire, and vegetation in northwestern Costa Rica, as revealed by sediment profiles from lakes on the seasonally dry, lower Pacific slope of Miravalles volcano in Guanacaste province (10.7o N, 85.2o W). Sediment cores were recovered for pollen and charcoal analysis from six lakes formed by volcanic activity approximately 8200 years ago. Six regional pollen zones were delineated based on changes in pollen and sediments, and dated by AMS radiocarbon determinations on macrofossils. The basal pollen zone (Zone 6, prior to 8000 cal yr BP) comprises elastic sediments that correspond to the interval of lake basin formation. Zone 5 (8000-7 500 cal yr BP) represents a transition to lacustrine sedimentation and shows increasing tree pollen percentages and abundant microscopic charcoal. During Zone 4 (7500-6800 cal yr BP) pollen assemblages indicate drier conditions, and the development of Myrica bogs in two basins; charcoal concentrations are highest in this zone. In Zone 3 (6800-5500 cal yr BP), tree pollen generally increases, but there is evidence of an episode of drier climate prior to 5500 cal yr BP. Zone 2 (5500-3700 cal yr BP) represents a period of prehistoric agriculture, punctuated by a dry period around 4000 cal yr BP. Maize pollen first appears at the base of the zone and is present throughout. Herbaceous pollen increases at the expense of tree pollen, and charcoal concentrations are high. Zone 1 (3700 cal yr BP to the present) also contains maize pollen, but charcoal concentrations decrease, and tree pollen remains low until modem times. Sediment characteristics indicate a drought interval at 2500 cal yr BP. The analysis of cores from multiple lakes made it possible to interpret regional as well as local changes, including shifts in climate and several drought episodes. Maize pollen grains deposited at 5500 cal yr BP constitute the earliest evidence of agriculture in Costa Rica, and document human occupation of the region 1500 years earlier than previously known. Charcoal profiles show that natural and anthropogenic fire has been part of this ecosystem for the past 8000 years

The Department of the Navy and Public Printing.

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