Diatom-based paleolimnological reconstruction of regional climate and local land-use change from a protected sinkhole lake in southern Florida, USA

Despite their sensitivity to climate variability, few of the abundant sinkhole lakes of Florida have been the subject of paleolimnological studies to discern patterns of change in aquatic communities and link them to climate drivers. However, deep sinkhole lakes can contain highly resolved paleolimnological records that can be used to track long-term climate variability and its interaction with effects of land-use change. In order to understand how limnological changes were regulated by regional climate variability and further modified by local land-use change in south Florida, we explored diatom assemblage variability over centennial and semi-decadal time scales in an ~11,000-yr and a ~150-yr sediment core extracted from a 21-m deep sinkhole lake, Lake Annie, on the protected property of Archbold Biological Station. We linked variance in diatom assemblage structure to changes in water total phosphorus, color, and pH using diatom-based transfer functions. Reconstructions suggest the sinkhole depression contained a small, acidic, oligotrophic pond ~11000–7000 cal yr BP that gradually deepened to form a humic lake by ~4000 cal yr BP, coinciding with the onset of modern precipitation regimes and the stabilization of sea-level indicated by corresponding palynological records. The lake then contained stable, acidophilous planktonic and benthic algal communities for several thousand years. In the early AD 1900s, that community shifted to one diagnostic of an even lower pH (~5.6), likely resulting from acid precipitation. Further transitions over the past 25 yr reflect recovery from acidification and intensified sensitivity to climate variability caused by enhanced watershed runoff from small drainage ditches dug during the mid-twentieth Century on the surrounding property.

Teacher perception of self -determination skills in the inclusive and special education classroom

It has been proposed that special education teachers, who promote self-determination and link it to educational standards, help students with a disability succeed in school. The current school reform movement has focused on accountability through mandates such as the No Child Left Behind Act, 2001, and has emphasized participation in the general curriculum through amendments to the Individuals with Disabilities Education Act (IDEA) of 1997 and 2004. This study informs educators if educational setting, students' type of disability, and subject area taught, influence teachers' opinions about the importance of teaching components leading to self-determination and self-management. ^ The research questions that drive this study are: (1) do secondary school teachers who instruct students with a disability think that self-determination components taught in the classroom will make an important difference in students' school and later postsecondary achievements? and (2) does the type of classroom setting, students' type of disability, or specific subject matter influence teachers' opinions regarding the importance of teaching components related to self-determination and self-management? The collection and interpretation of data were done using descriptive and quantitative methods employing a teacher survey. The survey was administered to secondary teachers who instruct students with disabilities. Data were analyzed using descriptive and inferential statistics. The sample consisted of 97 special education teachers currently teaching at the secondary level. ^ The results of the study indicated that teachers believe that self-determination is important for both school life and post school life. However teachers thought these skills to be more important for post school success. Teachers believe that self-determination is more important than self-management skills. Type of disability, educational environment, and subject area were not significant factors. ^

Civilizing the tropics: The highlanders' failed attempt to transform the Colombian Amazon, 1850--1930

The subject of this dissertation is the nature of the environmental transformations, both symbolic and physical, that took place in Colombia between 1850 and 1930. This period begins with the attempt by the Colombian elite to leave behind colonial ties, overcome economic disorganization, and link Colombia to the international market. These efforts were part of a general project to “civilize” this tropical country. The period closes with the transition toward an industrialization and urbanization process led by the Colombian state during the 1930s. ^ Frequently, environmental studies as an academic field are dominated by biological concerns. However, most environmental thinking accepts their interdisciplinary nature. Under this framework not only spatial but also symbolic concerns are key elements in understanding environmental transformations. ^ This study finds that despite several attempts to transform the Colombian landscape physically, most of the substantive changes were localized and circumscribed to the Andean region. Other changes were mainly symbolic. This dissertation thus uses the Amazon as one of several regions that did not experience significant changes in the forest canopy. While highlanders originally dreamed of the Amazon as an untapped El Dorado, their failed attempts to exploit the region caused them to imagine it as a nightmarish “green hell”. ^ This dissertation concentrates on three pairs of concepts: tropicality/civilization, landscape/territory, and symbolic/material changes. It presents both a general vision of Colombia and case studies of three regions: Cundinamarca, and Cauca Valley are used to compare with the Amazon region that is developed at length. Whereas mainstream Colombian histories have either fixated on the Andean highlands or, in a relegated second place, on the Caribbean region, this dissertation attempts to significantly contribute to the historiography of Colombia by focusing on the largely neglected Amazonian region. ^ To understand imageries about Colombia's landscape, the dissertation relies on travel writings, chorographic descriptions and maps. It also makes uses legal documents and other published primary sources, including literary pieces and memoirs. ^

A search for an exotic meson in the gamma + P decaying to delta++ + pi- + eta reaction

A Partial Waves Analysis (PWA) of γp → Δ ++X → pπ+ π - (η) data taken with the CLAS detector at Jefferson Lab is presented in this work. This reaction is of interest because the Δ++ restricts the isospin of the possible X states, leaving the PWA with a smaller combination of partial waves, making it ideal to look for exotic mesons. It was proposed by Isgur and Paton that photoproduction is a plausible source for the Jpc=1–+ state through flux tube excitation. The π1(1400) is such a state that has been produced with the use of hadron production but it has yet to be seen in photoproduction. A mass independent amplitude analysis of this channel was performed, followed by a mass dependent fit to extract the resonance parameters. The procedure used an event-based maximum likelihood method to maintain all correlations in the kinematics. The intensity and phase motion is mapped out for the contributing signals without requiring assumptions about the underlying processes. The strength of the PWA is in the analysis of the phase motion, which for resonance behavior is well defined. In the data presented, the ηπ– invariant mass spectrum shows contributions from the a0(980) and a2(1320) partial waves. No π1 was observed under a clear a2 signal after the angular distributions of the decay products were analyzed using an amplitude analysis. In addition, this dissertation discusses trends in the data, along with the implemented techniques.

Joint-specific changes in locomotor complexity in the absence of muscle atrophy following incomplete spinal cord injury

ackground Following incomplete spinal cord injury (iSCI), descending drive is impaired, possibly leading to a decrease in the complexity of gait. To test the hypothesis that iSCI impairs gait coordination and decreases locomotor complexity, we collected 3D joint angle kinematics and muscle parameters of rats with a sham or an incomplete spinal cord injury. Methods 12 adult, female, Long-Evans rats, 6 sham and 6 mild-moderate T8 iSCI, were tested 4 weeks following injury. The Basso Beattie Bresnahan locomotor score was used to verify injury severity. Animals had reflective markers placed on the bony prominences of their limb joints and were filmed in 3D while walking on a treadmill. Joint angles and segment motion were analyzed quantitatively, and complexity of joint angle trajectory and overall gait were calculated using permutation entropy and principal component analysis, respectively. Following treadmill testing, the animals were euthanized and hindlimb muscles removed. Excised muscles were tested for mass, density, fiber length, pennation angle, and relaxed sarcomere length. Results Muscle parameters were similar between groups with no evidence of muscle atrophy. The animals showed overextension of the ankle, which was compensated for by a decreased range of motion at the knee. Left-right coordination was altered, leading to left and right knee movements that are entirely out of phase, with one joint moving while the other is stationary. Movement patterns remained symmetric. Permutation entropy measures indicated changes in complexity on a joint specific basis, with the largest changes at the ankle. No significant difference was seen using principal component analysis. Rats were able to achieve stable weight bearing locomotion at reasonable speeds on the treadmill despite these deficiencies. Conclusions Decrease in supraspinal control following iSCI causes a loss of complexity of ankle kinematics. This loss can be entirely due to loss of supraspinal control in the absence of muscle atrophy and may be quantified using permutation entropy. Joint-specific differences in kinematic complexity may be attributed to different sources of motor control. This work indicates the importance of the ankle for rehabilitation interventions following spinal cord injury.