Improving parameterization of scalar transport through vegetation in a coupled ecosystem-atmosphere model

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references (p. 90-93).Several regional-scale ecosystem models currently parameterize subcanopy scalar transport using a rough-wall boundary eddy diffusivity formulation. This formulation predicts unreasonably high soil evaporation beneath tall, dense forests and low soil evaporation beneath short, sparse grass. This study investigates alternative formulations by reviewing literature on flow and scalar transport in canopies, taking field measurements of subcanopy latent heat flux, and testing alternative model formulations in constrained numerical experiments. A field campaign was conducted in a dense rainforest in Luquillo National Forest, Puerto Rico, to measure wind and fluxes with eddy covariance devices. Wind velocities and fluxes of latent heat, sensible heat, and momentum were found to be much smaller below the canopy than above it. Modeling experiments tested a mixing-layer-based formulation of eddy diffusivity and a soil evaporation cutoff based on vortex penetration depth. The vortex penetration cutoff was found to be the most physically accurate and computationally simple option, and this study recommends that ecosystem and land-surface models adopt this formulation for subcanopy scalar transport.by Percy Anne Link.M.Eng

Lummi Island ferry relocation

This Environmental Impact Assessment (EIA) has been composed by a group of Huxley students under the supervision of Dr. Leo Bodensteiner. Together, we have analyzed the proposed plan for the relocation of the Lummi Island ferry docks located on Lummi Island and Gooseberry Point. The end of a 25-year lease and the proposed removal of the Gooseberry Point dock spurred the possible relocation. Our discussion includes the current proposal and two alternatives for the ferry routes. The alternatives include the transfer to either the Bellingham Cruise Terminal or Whatcom Waterway. Existing conditions and impacts are outlined within the EIA

Inventory study of an early pandemic COVID- 19 cohort in South-Eastern Sweden, focusing on neurological manifestations

Background Neurological manifestations in patients with COVID-19 have been reported previously as outcomes of the infection. The purpose of current study was to investigate the occurrence of neurological signs and symptoms in COVID-19 patients, in the county of 6sterg\uf6tland in southeastern Sweden. Methods This is a retrospective, observational cohort study. Data were collected between March 2020 and June 2020. Information was extracted from medical records by a trained research assistant and physician and all data were validated by a senior neurologist. Results Seventy-four percent of patients developed at least one neurological symptom during the acute phase of the infection. Headache (43%) was the most common neurological symptom, followed by anosmia and/or ageusia (33%), confusion (28%), hallucinations (17%), dizziness (16%), sleep disorders in terms of insomnia and OSAS (Obstructive Sleep Apnea) (9%), myopathy and neuropathy (8%) and numbness and tingling (5%). Patients treated in the ICU had a higher male presentation (73%). Several risk factors in terms of co-morbidities, were identified. Hypertension (54.5%), depression and anxiety (51%), sleep disorders in terms of insomnia and OSAS (30%), cardiovascular morbidity (28%), autoimmune diseases (25%), chronic lung diseases (24%) and diabetes mellitus type 2 (23%) founded as possible risk factors. Conclusion Neurological symptoms were found in the vast majority (74%) of the patients. Accordingly, attention to neurological, mental and sleep disturbances is warranted with involvement of neurological expertise, in order to avoid further complications and long-term neurological effect of COVID-19. Furthermore, risk factors for more severe COVID-19, in terms of possible co-morbidities that identified in this study should get appropriate attention to optimizing treatment strategies in COVID-19 patients

Tropical Atlantic climate response to low-latitude and extratropical sea-surface temperature : a Little Ice Age perspective

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 36 (2009): L11703, doi:10.1029/2009GL038677.Proxy reconstructions and model simulations suggest that steeper interhemispheric sea surface temperature (SST) gradients lead to southerly Intertropical Convergence Zone (ITCZ) migrations during periods of North Atlantic cooling, the most recent of which was the Little Ice Age (LIA; ∼100–450 yBP). Evidence suggesting low-latitude Atlantic cooling during the LIA was relatively small (<1°C) raises the possibility that the ITCZ may have responded to a hemispheric SST gradient originating in the extratropics. We use an atmospheric general circulation model (AGCM) to investigate the relative influence of low-latitude and extratropical SSTs on the meridional position of the ITCZ. Our results suggest that the ITCZ responds primarily to local, low-latitude SST anomalies and that small cool anomalies (<0.5°C) can reproduce the LIA precipitation pattern suggested by paleoclimate proxies. Conversely, even large extratropical cooling does not significantly impact low-latitude hydrology in the absence of ocean-atmosphere interaction.This work was supported by NSF grants OCE 0623364 and ATM 033746 as well as the student research fund of MIT’s Department of Earth, Atmospheric and Planetary Science

Developmental expression of 4-repeat-Tau induces neuronal aneuploidy in Drosophila tauopathy models

Tau-mediated neurodegeneration in Alzheimer's disease and tauopathies is generally assumed to start in a normally developed brain. However, several lines of evidence suggest that impaired Tau isoform expression during development could affect mitosis and ploidy in post-mitotic differentiated tissue. Interestingly, the relative expression levels of Tau isoforms containing either 3 (3R-Tau) or 4 repeats (4R-Tau) play an important role both during brain development and neurodegeneration. Here, we used genetic and cellular tools to study the link between 3R and 4R-Tau isoform expression, mitotic progression in neuronal progenitors and post-mitotic neuronal survival. Our results illustrated that the severity of Tau-induced adult phenotypes depends on 4R-Tau isoform expression during development. As recently described, we observed a mitotic delay in 4R-Tau expressing cells of larval eye discs and brains. Live imaging revealed that the spindle undergoes a cycle of collapse and recovery before proceeding to anaphase. Furthermore, we found a high level of aneuploidy in post-mitotic differentiated tissue. Finally, we showed that overexpression of wild type and mutant 4R-Tau isoform in neuroblastoma SH-SY5Y cell lines is sufficient to induce monopolar spindles. Taken together, our results suggested that neurodegeneration could be in part linked to neuronal aneuploidy caused by 4R-Tau expression during brain development

Tracer Survey in the Cape Verde Region Traceraufnahme in der Kapverdenregion Cruise No. 10, Leg 1 October 31 – December 06, 2008 Ponta Delgada (Portugal) – Mindelo (Cape Verde Islands)

The research cruise MSM10/1 was extremely successful. All programs were able to collect high quality data and the anticipated goals of the expedition were fully met. We have been able to carry out the first comprehensive survey of a tracer release in the Guinea Upwelling region (GUTRE) roughly seven month after the tracer was released at 8°N 23°W in April 2008. We have estimated that a total of 40% of the tracer was found during this cruise. While the horizontal spreading and mixing was larger than anticipated, the vertical extent of the tracer found was small. The low vertical tracer spreading rate estimates are supported by the micro structure profile data. The extensive survey of the upper 1000m of the oxygen minimum zone (OMZ) allowed comparing our sections with several previous surveys. We found that the lowest oxygen values in the core of the OMZ have dropped at record low values below 40 μmol/kg. The preliminary findings from the trace metal work focused on Fe ligand measurements shows a slight higher excess ligand concentration in the surface (50m) for three stations. The two other stations show a slight decrease at this depth. A large number of biochemical samples were taken and were analyzed in Kiel for DNA and RNA diversity. The tracer release experiment provided an ideal environment for repeated biochemical sampling in the same water mass

The use of mental imagery by aesthetic athletes prior to competition

xi, 64 leaves : ill. ; 28 cmThis study examined the influence of state-confidence on aesthetic athletes’ precompetitive imagery function use. Important individual differences effecting functional imagery use require empirical confirmation. Proposed is state-confidence as a factor influencing the functions of imagery used immediately prior to competition. Also, sport type may also be a moderator of the relationship and thus, is constrained in this study. Female aesthetic athletes from Southern Alberta (N = 180, Mage = 14.64, SD = 1.88) completed measures of state-confidence, imagery ability, and frequency of imagery function use. One-way ANCOVA tests revealed that athletes with high state-confidence used significantly more cognitive specific, cognitive general, motivation general-arousal, and motivational general-mastery functions of imagery than low state-confident athletes. Findings imply that applied sport psychology consultants should be more encouraging of preparation strategies with low state-confident athletes