MIXING, METABOLISM, AND CLIMATE CHANGE: A MODELING CASE STUDY OF A SHALLOW HYPEREUTROPHIC, POLYMICTIC LAKE

Globally, lakes are sites of significant carbon cycling, respiring an estimated 0.07 to 0.15 Pg as CO2 and sequestering 0.03 to 0.07 Pg C in sediments annually. These processes can be affected by nutrient availability, with seasonal mixing regulating nutrient transport in monomictic and dimictic systems. However, the effect of intermittent mixing on ecosystem production in polymictic systems has been much less studied. The timing and frequency of lake mixing are expected to be altered by climate change, which has the potential to impact nutrient transport. The first chapter of this thesis introduces lake mixing dynamics and indices of mixing. In chapter two, the relationship between intermittent mixing and changes in productivity in polymictic systems is examined, under the hypothesis that productivity will increase in response to lake mixing. Ecosystem productivity was calculated via the diel oxygen technique for Goose Lake, Marquette Co., MI, over the 2019 field season. The diel changes in Net Ecosystem Production (NEP), Gross Primary Production (GPP), and Respiration (R) were cross-correlated with the diel change in Lake Number (LN), an index of stratification. One day after mixing, dNEP dt-1 and dGPP dt-1 were negatively correlated with dLN dt-1 with coefficients of -0.342 and - 0.209, respectively, at a cross correlation significance threshold of ±0.1859. This corresponds to an increase in NEP and GPP as LN decreases. These correlations suggest that GPP and NEP increase in response to mixing. In chapter three, climate-driven changes in stratification extent and mixing frequency are modeled for the early 2080’s relative to 2019. The one-dimensional General Lake Model (GLM) was autocalibrated for 2019 conditions using simulated annealing. The cost function consisted of the sum of temperature and Lake Number Normalized Root Mean Squared Error (NRMSE) to improve vertical heat distribution. Six Coupled Model Intercomparison Project 5 (CMIP5) climate models for the early 2080’s were input into the GLM model to determine changes in hydrodynamics. In all future scenarios, stratification extent and water temperatures increased relative to 2019. However, mixing frequency also increased and the lake remained polymictic. This increase in stratification is likely due to both increased air temperatures and lower wind speeds. Increased stratification and temperatures will likely exacerbate existing water quality problems by stimulating DO drawdowns and internal loading of phosphorus. These conditions will increase the probability of cyanobacteria blooms. Higher temperatures will likely shift the system further towards net heterotrophy due to the greater temperature dependence of respiration than photosynthesis. While the number of mixing events increased, this was due to significantly increased stratification which would be expected to decrease productivity. Therefore, it cannot be conclusively determined if productivity will increase in Goose Lake in response to climate change

Ascaroside Signaling Is Widely Conserved among Nematodes

Background: Nematodes are among the most successful animals on earth and include important human pathogens, yet little is known about nematode pheromone systems. A group of small molecules called ascarosides has been found to mediate mate finding, aggregation, and developmental diapause in Caenorhabditis elegans, but it is unknown whether ascaroside signaling exists outside of the genus Caenorhabditis. Results: To determine whether ascarosides are used as signaling molecules by other nematode species, we performed a mass spectrometry-based screen for ascarosides in secretions from a variety of both free-living and parasitic (plant, insect, and animal) nematodes. We found that most of the species analyzed, including nematodes from several different clades, produce species-specific ascaroside mixtures. In some cases, ascaroside biosynthesis patterns appear to correlate with phylogeny, whereas in other cases, biosynthesis seems to correlate with lifestyle and ecological niche. We further show that ascarosides mediate distinct nematode behaviors, such as retention, avoidance, and long-range attraction, and that different nematode species respond to distinct, but overlapping, sets of ascarosides. Conclusions: Our findings indicate that nematodes utilize a conserved family of signaling molecules despite having evolved to occupy diverse ecologies. Their structural features and level of conservation are evocative of bacterial quorum sensing, where acyl homoserine lactones (AHLs) are both produced and sensed by many species of gram-negative bacteria. The identification of species-specific ascaroside profiles may enable pheromone-based approaches to interfere with reproduction and survival of parasitic nematodes, which are responsible for significant agricultural losses and many human diseases worldwide

Effect of clear cutting on snow accumulation and water outflow at Fraser, Colorado

Employment and the journey to work have long been a focus of transportation study. Although today, the work trip accounts for a much smaller share of total trips than it did a few decades ago, there are several reasons why this subject deserves our continued attention.In planning for the journey to work, it is important to have an understanding of the anticipated growth in jobs in the coming years. Both the location of job growth and the types of jobs are important; the geographical distribution of jobs will affect transport needs, and different industries and occupations are associated with different land use patterns and transportation behaviors. This paper presents a review and analysis of California's job trends

The GNAQ in the haystack: intramedullary meningeal melanocytoma of intermediate grade at T9-10 in a 58-year-old woman

Meningeal melanocytomas are rare tumors. They are derived from leptomeningeal melanocytes and predominantly occur along the spine and the posterior fossa. Here, the authors report a case of intramedullary melanocytoma of intermediate grade in a 58-year-old female patient who was initially misdiagnosed with malignant melanoma until mutational analyses of a panel of genes associated with melanotic tumors led to reclassification

Comparative Metabolomics Reveals Biogenesis of Ascarosides, a Modular Library of Small-Molecule Signals in C. elegans

In the model organism Caenorhabditis elegans, a family of endogenous small molecules, the ascarosides function as key regulators of developmental timing and behavior that act upstream of conserved signaling pathways. The ascarosides are based on the dideoxysugar ascarylose, which is linked to fatty-acid-like side chains of varying lengths derived from peroxisomal β-oxidation. Despite the importance of ascarosides for many aspects of C. elegans biology, knowledge of their structures, biosynthesis, and homeostasis remains incomplete. We used an MS/MS-based screen to profile ascarosides in C. elegans wild-type and mutant metabolomes, which revealed a much greater structural diversity of ascaroside derivatives than previously reported. Comparison of the metabolomes from wild-type and a series of peroxisomal β-oxidation mutants showed that the enoyl CoA-hydratase MAOC-1 serves an important role in ascaroside biosynthesis and clarified the functions of two other enzymes, ACOX-1 and DHS-28. We show that, following peroxisomal β-oxidation, the ascarosides are selectively derivatized with moieties of varied biogenetic origin and that such modifications can dramatically affect biological activity, producing signaling molecules active at low femtomolar concentrations. Based on these results, the ascarosides appear as a modular library of small-molecule signals, integrating building blocks from three major metabolic pathways: carbohydrate metabolism, peroxisomal β-oxidation of fatty acids, and amino acid catabolism. Our screen further demonstrates that ascaroside biosynthesis is directly affected by nutritional status and that excretion of the final products is highly selective

Role of carbon dioxide and ion transport in the formation of sub-embryonic fluid by the blastoderm of the Japanese quail

1. The explanted blastoderm of the Japanese quail was used to explore the role of ions and carbon dioxide in determining the rate of sub-embryonic fluid (SEF) production between 54 and 72 h of incubation. 2. Amiloride, an inhibitor of Na+/H+ exchange, at concentrations of 10-3 to 10-6 M substantially decreased the rate of SEF production when added to the albumen culture medium. N-ethylmaleimide, an inhibitor of V type H+ ATPase, also decreased this rate but only to a small extent at the highest dose applied, 10-3 M. Both inhibitors had no effect on SEF production when added to the SEF. 3. The inhibitors of cellular bicarbonate and chloride exchange, 4-acetamido-4-'isothiocyano-2, 2-'disulphonic acid (SITS) and 4,4'diisothiocyanostilbene-2,2-'disulphonic acid (DIDS), had no effect upon SEF production. 4. Ouabain, an inhibitor of Na+/K+ ATPase, decreased SEF production substantially at all concentrations added to the SEF (10-3 to 10-6 M). Three sulphonamide inhibitors of carbonic anhydrase, acetazolamide, ethoxzolamide and benzolamide, decreased SEF production when added to the SEF at concentrations of 10-3 to 10-6 M. Benzolamide was by far the most potent. Neither ouabain nor the sulphonamides altered SEF production when added to the albumen culture medium. 5. Using a cobalt precipitation method, carbonic anhydrase activity was localised to the endodermal cells of the area vasculosa. The carbonic anhydrase activity was primarily associated with the lateral plasma membranes, which together with the potent inhibitory effect of benzolamide, suggests the carbonic anhydrase of these cells is the membrane-associated form, CA IV. 6. The changes in SEF composition produced by inhibitors were consistent with the production of SEF by local osmotic gradients. 7. It is concluded that a Na+/K+ ATPase is located on the basolateral membranes of the endodermal cells of the area vasculosa , and that a sodium ion/hydrogen ion exchanger is located on their apical surfaces. Protons for this exchanger would be provided by the hydration of CO2 catalysed by the membrane-associated carbonic anhydrase. Furthermore, it is proposed that the prime function of the endodermal cells of the area vasculosa is the production of SEF

Adaptation of an Evaluation System for e-Health Environments

Proceedings of: 14th International Conference, KES 2010, Cardiff, UK, September 8-10, 2010The increase in ageing of European population implies a high cost in economy and society in any European country and it can be reduced if we pay attention and develop home care systems. Evaluation of these systems is a critical and challenging issue but seldom tackled. It is important before evaluating a system to figure out what is the evaluation goal. In our case, such a goal is to evaluate enhanced user experience and beyond the evaluation goal it is also a central concern about what to evaluate. In this paper we propose a multi-agent home care system where we describe how agents coordinate their decisions to provide e-services to patients when at home after hospitalization. Finally we center our proposal on the adaptation of an evaluation system, previously developed, to support the challenges of an e-Health environment and also the multi-user evaluation. These evaluation methods (online/offline) will provide user's (patients, patient's relatives and healthcare professionals) feedback into the system.This work was supported in part by Projects CICYT TIN2008-06742-C02-02/ TSI, CICYT TEC2008-06732-C02-02/TEC, CAM CONTEXTS (S2009/ TIC-1485) and DPS2008-07029-C02-02.Publicad

Varicella vaccination coverage of children under two years of age in Germany

Background: Since July 2004, routine varicella vaccination is recommended by the German Standing Vaccination Committee in Germany. Health Insurance Funds started to cover vaccination costs at different time points between 2004 and 2006 in the Federal States. Nationwide representative data on vaccination coverage against varicella of children under two years of age are not available. We aimed to determine varicella vaccination coverage in statutory health insured children under two years of age in twelve German Federal States using data from associations of statutory health insurance physicians (ASHIPs), in order to investigate the acceptance of the recommended routine varicella vaccination programme. Methods: We analysed data on varicella vaccination from 13 of 17 ASHIPs of the years 2004 to 2007. The study population consisted of all statutory health insured children under two years of age born in 2004 (cohort 2004) or 2005 (cohort 2005) in one of the studied regions. Vaccination coverage was determined by the number of children vaccinated under 2 years of age within the study population. Results: Varicella vaccination coverage of children under two years of age with either one dose of the monovalent varicella vaccine or two doses of the measles, mumps, rubella, and varicella vaccine increased from 34% (cohort 2004) to 51% (cohort 2005) in the studied regions (p < 0.001). More than half of the vaccinated children of cohort 2004 and two third of cohort 2005 were immunised at the recommended age 11 to 14 months. The level of vaccination coverage of cohort 2004 was significantly associated with the delay in introduction of cost coverage since the recommendation of varicella vaccination (p < 0.001). Conclusions: Our study shows increasing varicella vaccination coverage of young children, indicating a growing acceptance of the routine varicella vaccination programme by the parents and physicians. We recommend further monitoring of vaccination coverage using data from ASHIPs to investigate acceptance of the routine vaccination programmes over time

Singaporean caregivers’ experiences of placing a relative into long term care

Caregivers experience many difficulties and challenges with the process of providing care particularly at times of transition, such as when the care recipient moves into a nursing home. This qualitative study aims to understand caregiver experiences of this important process. Methods: Twelve interviews were conducted with caregivers with an older relative in a nursing home in Singapore. The resulting data was analysed through thematic analysis. Results: Five themes were identified: Filial and cultural expectations shape caregivers’ experience of pre-placement decisions and post-placement; View of the placement decision; Continued impact of caring; Engagement with the institution and Maintaining the relationship. Conclusions: Caregivers were found to place significant emphasis on cultural values, specifically on filial piety. This impacted their caregiving role prior to placement, when making the decision to place their relative into a nursing home and in their continued involvement after placement. Despite the changing role, the placement experience was fraught with persisting difficulties involving maintaining the relationship with the resident and developing a new relationship with the nursing home