203 research outputs found
The effect of habitat change on nutrient removal in the Atchafalaya River Basin, Louisiana
The Mississippi and Atchafalaya rivers are the major sources of freshwater and nutrients to the Gulf of Mexico. Increased nutrient loads from these rivers exacerbate eutrophication in coastal receiving waters and contribute to the large area of hypoxia that develops seasonally in the Gulf. Levees along the Mississippi River have reduced contact between the river and the historic floodplain; this limits the ability of floodplain wetlands to naturally mitigate excess nutrients. However, the Atchafalaya River diverges from the Mississippi 217 km from the Gulf and enters a large river floodplain with a widely spaced levee system. This enhances the ability of the Atchafalaya River Basin to remove and sequester nutrients, potentially reducing downstream eutrophication. Overbank flow spreads river-water and sediment across the floodplain. Over time, sedimentation has filled in many of the open water areas on the floodplain, such that lakes are transitioning to baldcypress swamps and bottomland hardwood forests. These habitats differ in their available nutrient reservoirs and the rates at which they transform and store nutrients. This dissertation investigated the major retention and removal mechanisms for carbon, nitrogen, and phosphorus within bottomland hardwood forests, baldcypress swamps, and lakes of the Atchafalaya River Basin. These reservoirs include denitrification, sedimentation, and assimilation by aboveground biomass. Results estimate that nutrient retention and removal within bottomland hardwood forests ranges from 1,177,605—1,561,805 t C yr-1, 46,049—47,603 t N yr-1 and 20,040—20,175 t P yr-1. Within baldcypress swamps, rates range from 493,953—600,180 t C yr-1, 21,821—22,364t N yr-1 and 2,168—2,202 t P yr-1. Rates in the lakes were 57,490 t C yr-1, 5,140—5,390 t N yr-1 and 2,550 t P yr-1. Total retention and removal for the entire basin is on the order of 1,177,605—1,561,805 t C yr-1, 46,049—47,603 t N yr-1, and 20,040—20,175 t P yr-1. Rates varied by habitat, highlighting the need to consider habitat change when developing management strategies to improve water quality. Data from this dissertation can be used to parameterize nutrient models for the Atchafalaya River Basin, as well as for river diversions and floodplains with similar habitat types
Gauging Residential Knowledge and Behavior to Inform Stormwater Outreach Efforts across South Carolina
Public outreach and education are important components of local stormwater management efforts aimed at protecting water quality and reducing pollutants of concern. Increasingly, educators recognize that creating effective outreach material depends on an understanding of the target audience, their current behavior, and their barriers and motivations to adopting pro-environmental behaviors. Clemson Extension’s Carolina Clear program partners with 39 communities across South Carolina to provide compliance-based stormwater education and outreach. On behalf of these community partners, Carolina Clear conducted the third iteration of a telephone survey to gauge local knowledge, perceptions, and behaviors of residents related to stormwater and watershed health. Results presented here will highlight key knowledge gaps (e.g., the misconception that stormwater runoff is treated) and behaviors (e.g., dumping down storm drains) that could potentially be targeted through education and removal of barriers (e.g., storm drain markings). Survey results showed ongoing misperceptions about the major sources of stormwater pollution, whether stormwater is treated, and what behaviors generate pollution. However, results also show a high level of concern about water quality, as well as a desire to practice pro-environmental behavior. Highlighting the connection between potential sources of pollution, such as pet waste and septic systems, and impacts, such as shellfish bed closures and swimming restrictions, could provide stronger awareness and motivation, particularly among the large number of residents who enjoy visiting beaches and who swim, fish, and boat in local waterways. Ultimately, the survey results can be used by a variety of educators and practitioners statewide to better understand and identify target audiences and to guide the development of stormwater programming that addresses these knowledge gaps. Conducting focus groups with subpopulations of residents is recommended as a next step to further identify specific motivations within subpopulations of residents. Combining the survey results with focus-group data can help educators remove barriers to taking action and further motivate behavior change
A novel RUNX1 mutation with ANKRD26 dysregulation is related to thrombocytopenia in a sporadic form of myelodysplastic syndrome
Aging is associated with a higher risk of developing malignant diseases, including myelodysplastic syndromes, clonal disorders characterised by chronic cytopenias (anaemia, neutropenia and thrombocytopenia) and abnormal cellular maturation. Myelodysplastic syndromes arising in older subjects are influenced by combinations of acquired somatic genetic lesions driving evolution from clonal haematopoiesis to myelodysplastic syndromes and from myelodysplastic syndromes to acute leukaemia. A different pattern of mutations has been identified in a small subset of myelodysplastic syndromes arising in young patients with familial syndromes. In particular, dysregulation of ANKRD26, RUNX1 and ETV6 genes plays a role in familial thrombocytopenia with predisposition to myelodysplastic syndromes and acute leukaemia. Whether these genes affect thrombopoiesis in sporadic myelodysplastic syndrome with thrombocytopenia is still undefined. Thirty-one myelodysplastic syndromes subjects and 27 controls subjects were investigated. Genomic DNA was used for mutation screening (ETV6, RUNX1, 5′UTR ANKRD26 genes). Functional studies were performed in the MEG-01-akaryoblastic cell line. We found four novel variants of RUNX1 gene, all in elderly myelodysplastic syndromes subjects with thrombocytopenia. Functional studies of the variant p.Pro103Arg showed no changes in RUNX1 expression, but the variant was associated with deregulated high transcriptional activity of ANKRD26 in MEG-01 cells. RUNX1 variant p.Pro103Arg was also associated with increased viability and reduced apoptosis of MEG-01, as well as impaired platelet production. Our findings are consistent with dysregulation of ANKRD26 in RUNX1 haploinsufficiency. Lack of repression of ANKRD26 expression may contribute to thrombocytopenia of subjects with sporadic myelodysplastic syndromes
Cyclic Cushing's syndrome: an overview
Cyclic Cushing's syndrome (CS) is a disorder in which glucocorticoid levels are alternately normal and high, the latter occurring in episodes that can last from a few days to several months. It is more common in children than in adults. Cyclic CS may be either of the two different forms of CS (ACTH-dependent or -independent CS). Clinically, it may present with one or many symptoms, depending on the duration of disease activity and the timing of the fluctuations. A serotoninergic influence, cyclic changes in central dopaminergic tone, spontaneous episodic hemorrhage in the tumor, and the action of inflammatory cytokines with antitumor properties are some of the mechanisms suggested to explain the physiopathology of this phenomenon but the exact mechanism remains to be clarified. The cyclic pattern of hypercortisolism can delay the final diagnosis of CS and make it difficult to interpret the results of dynamic tests. Patients may have paradoxical responses to dexamethasone that can reflect increasing or decreasing levels of endogenous activity. Hormone assessments have to be repeated periodically when a diagnosis of CS is suspected. The cyclic pattern can also interfere with medical treatment because patients may show unexpected clinical and biochemical signs of hypocortisolism when cortisol secretion cyclically returns to normal, so an accurate follow-up is mandatory in these patients
Tratamiento biológico de lixiviados de residuos sólidos urbanos con estiércol porcino
La fracción orgánica de los residuos sólidos urbanos como pecuarios son fuentes de contaminación, produciendo un impacto por significar un vector de enfermedades. En el presente trabajo se investiga el tratamiento anaeróbico de los residuos resultantes-de la actividad pecuaria mezclados con los lixiviados de la fracción orgánica provenientes de una feria de frutas y verduras municipal, con una relación DQO/N=17,75 y N/P=9. Se comparó este sustrato con medio sintético con una relación DQO/N=34,35 y N/P=7,99.
La remoción de DQO obtenida al cabo de quince dÃas para la mezcla de lixiviados fue de 23,78 %, con una producción de gas metano del 70 %.
El método de tratamiento en estudio es factible de realizar. Para lograr un aumento de remoción de DQO es necesario mejorar la relación DQO/N aportando materia orgánica extra o disminuyendo la cantidad de nitrógeno con un post-tratamiento.Tema: Tratamiento de efluentes. Biomasa.Asociación Argentina de EnergÃa Sola
Tratamiento biológico de lixiviados de residuos sólidos urbanos con estiércol porcino
La fracción orgánica de los residuos sólidos urbanos como pecuarios son fuentes de contaminación, produciendo un impacto por significar un vector de enfermedades. En el presente trabajo se investiga el tratamiento anaeróbico de los residuos resultantes-de la actividad pecuaria mezclados con los lixiviados de la fracción orgánica provenientes de una feria de frutas y verduras municipal, con una relación DQO/N=17,75 y N/P=9. Se comparó este sustrato con medio sintético con una relación DQO/N=34,35 y N/P=7,99.
La remoción de DQO obtenida al cabo de quince dÃas para la mezcla de lixiviados fue de 23,78 %, con una producción de gas metano del 70 %.
El método de tratamiento en estudio es factible de realizar. Para lograr un aumento de remoción de DQO es necesario mejorar la relación DQO/N aportando materia orgánica extra o disminuyendo la cantidad de nitrógeno con un post-tratamiento.Tema: Tratamiento de efluentes. Biomasa.Asociación Argentina de EnergÃa Sola
Clinical presentation and management of acromegaly in elderly patients
Background and aim: Acromegaly is a rare disease with a peak of incidence in early adulthood. However, enhanced awareness of this disease, combined with wide availability of magnetic resonance imaging (MRI), has increased the diagnosis of forms with mild presentation, especially in elderly patients. Moreover, due to increased life expectancy and proactive individualized treatment, patients with early-onset acromegaly are today aging. The aim of our study was to describe our cohort of elderly patients with acromegaly. Materials and methods: This is a cross-sectional retrospective study of 96 outpatients. Clinical, endocrine, treatment, and follow-up data were collected using the electronic database of the University Hospital of Padova, Italy. Results: We diagnosed acromegaly in 13 patients, aged 6565\ua0years, presenting with relatively small adenomas and low IGF-1 secretion. Among them, 11 patients were initially treated with medical therapy and half normalized hormonal levels after 6\ua0months without undergoing neurosurgery (TNS). Remission was achieved after TNS in three out of four patients (primary TNS in two); ten patients presented controlled acromegaly at the last visit. Acromegaly-related comorbidities (colon polyps, thyroid cancer, adrenal incidentaloma, hypertension, and bone disease) were more prevalent in patients who had an early diagnosis (31 patients, characterized by a longer follow-up of 24\ua0years) than in those diagnosed aged 6565\ua0years (5\ua0years of follow-up). Conclusions: Elderly acromegalic patients are not uncommon. Primary medical therapy is a reasonable option and is effectively used, while the rate of surgical success is not reduced. A careful cost-benefit balance is suggested. Disease-specific comorbidities are more prevalent in acromegalic patients with a longer follow-up rather than in those diagnosed aged 6565\ua0years
Astrocytes-derived extracellular vesicles in motion at the neuron surface: Involvement of the prion protein
Astrocytes-derived extracellular vesicles (EVs) are key players in glia-neuron communication. However, whether EVs interact with neurons at preferential sites and how EVs reach these sites on neurons remains elusive. Using optical manipulation to study single EV-neuron dynamics, we here show that large EVs scan the neuron surface and use neuronal processes as highways to move extracellularly. Large EV motion on neurites is driven by the binding of EV to a surface receptor that slides on neuronal membrane, thanks to actin cytoskeleton rearrangements. The use of prion protein (PrP)-coated synthetic beads and PrP knock out EVs/neurons points at vesicular PrP and its receptor(s) on neurons in the control of EV motion. Surprisingly, a fraction of large EVs contains actin filaments and has an independent capacity to move in an actin-mediated way, through intermittent contacts with the plasma membrane. Our results unveil, for the first time, a dual mechanism exploited by astrocytic large EVs to passively/actively reach target sites on neurons moving on the neuron surface
The GIP/GIPR axis is functionally linked to GH-secretion increase in a significant proportion of gsp(-) somatotropinomas
Glucose-dependent insulinotropic polypeptide receptor (GIPR) overexpression has been recently described in a proportion of gsp(-) somatotropinomas and suggested to be associated with the paradoxical increase of GH (GH-PI) during an oral glucose load
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