49 research outputs found

    Urease Activity in a Kentucky Bluegrass Turf

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    The components of a turfgrass ecosystem, including plants, an intervening layer of thatch and the underlying soil, influence the fate of topically applied urea fertilizer. The loss of urea N by ammonia volatilization may be governed by the rate of urea hydrolysis. The main objective of this study was to determine the extent of urease activity associated with turfgrass plant tissue, thatch, and the underlying soil. This information may help elucidate the mechanism of ammonia loss following urea application. Because a turfgrass stand frequently possesses an extensive thatch layer that may serve as the primary plant growth medium, additional objectives included: i) determining the effects of air drying and seasonal variation on the activity of urease in thatch; ii) determining the variability in thatch urease activity by analyzing multiple field samples; and iii) determining the variation of urease activity within a thatch profile. Turfgrass clippings, thatch, and underlying Flanagan silt loam soil (Aquic Argiudoll) samples were taken from a field-grown Kentucky bluegrass (Poa pratensis L.) turf in either September 1980 or March 1981. On a dry weight basis, urease activity was 18 to 30 times higher from turfgrass clippings and thatch than from soil. Air drying thatch increased urease activity by 20 % over moist samples while air drying soil samples had no apparent effect. Greenhouse incubation of winter-dormant thatch samples increased urease activity 40 %, presumably in response to the duration of increased temperature. Thatch urease activity varied between sampling sites but still remained extremely high compared to soil activity. Within each thatch sample (1 X 1 X 2 cm), urease activity was highest in the upper 1.0 cm of the profile. It was concluded that thatch urease activity was variable in nature depending upon seasonal conditions which contrasts sharply with extremely stable soil urease activities. These findings suggest that, because of the high level of urease in thatch, ammonia volatilization will occur from most urea-treated turfgrass stands, regardless of the type of underlying soil unless the urea is thoroughly washed into the soil

    Denitrification Losses from Kentucky Bluegrass Sod

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    Il sistema di monitoraggio sismico dell’Osservatorio Vesuviano – INGV

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    Obiettivo principale del monitoraggio dei vulcani attivi è individuare e misurare fenomeni che possono essere indotti dal movimento del magma in profondità. Dal punto di vista sismologico questi fenomeni possono essere sciami sismici, eventi a bassa frequenza, microtremore vulcanico ed eventi very long period (VLP). Attraverso la misura, l'analisi e la corretta interpretazione di questi fenomeni è possibile capire in anticipo se un vulcano sta evolvendo verso una ripresa dell'attività eruttiva. L'Osservatorio Vesuviano - INGV ha tra i suoi compiti istituzionali il monitoraggio del Vesuvio, dei Campi Flegrei e di Ischia che sono, come è noto, vulcani a alto rischio a causa del loro stile eruttivo prevalentemente esplosivo e della presenza nelle loro prossimità di vaste aree urbanizzate. Per effettuare il monitoraggio sismologico di dette aree l'Osservatorio Vesuviano ha sviluppato e mantiene una rete che trasmette i dati in continuo al centro di sorveglianza. La configurazione attuale della rete comprende 28 stazioni analogiche a corto periodo (1Hz) e 4 stazioni digitali a larga banda.PublishedRoma1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope

    Multiple Primary Recurrent Basaliomas (mPR-BCCs) of the Scalp with Cranial Bone Invasion

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    We present a 68-year-old patient with multiple primary infiltrative BCCs in the scalp area, initially treated 14 years ago with superficial contact X-ray therapy, end dose 60 greys, followed by electrocautery (x2) several years later. He presented in the dermatologic policlinic for diagnosis and therapy of two additional, newly-formed pigmented lesions, and because of an uncomfortable, itchy, burning sensation in the area where lesions had been treated years before. Screening cranial computer-tomography (CT) examination revealed two deformities in the form of tumor-mediated osteolysis, affecting the diploe of the tabula externa on the left parietal and parasagittal areas. Complete excision with removal of periosteum and partial removal of the tabula externa was planned with neurosurgeons at a later stage. BCC is one of the most common malignant skin tumours of the head and neck region (about 90% of cases) and is characterised by a significant potential for local infiltration and destructive growth. Recurrent, invasive BCC of the scalp and calvarium is a difficult problem for which universally accepted treatment protocols had not been established. The primary treatment of aggressive BCCs is surgical, with a thorough examination of excision margins to ensure complete resection. Procedural-based options include standard excision, curettage, curettage with electrodessication, and Mohs micrographic surgery (MMS), with MMS being the gold standard for the definitive treatment of BCC. Improper removal or electrocautery (as in our case) of the several aggressive forms of BCC seems to be a particular problem, and not only for dermatologic surgeons. The risk of subsequent invasion and destruction of the cranium, underlying dura, and cranial nerves by basal cell carcinoma (BCC) is extremely low, with an estimated incidence of 0.03%, but is a potential complication over time. Computed tomography is the modality of choice for detecting tumour invasion into bone, which commonly appears as irregular demineralization or osteolysis

    Interstitial Granulomatous Dermatitis (IGD)

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    We report the case of a 42 years old male patient suffering from skin changes , which appeared in the last 7-8 years.  Two biopsies were performed during the evolution of the lesion. Both showed similar findings that consisted in a busy dermis with interstitial, superficial and deep infiltrates of lymphocytes and histiocytes dispersed among collagen bundles, with variable numbers of neutrophils scattered throughout. Some histiocytes were clustered in poorly formed granuloma that included rare giant cells, with discrete Palisades and piecemeal collagen degeneration, but without mucin deposition or frank necrobiosis of collagen. The clinical and histologic findings were supportive for interstitial granulomatous dermatitis. Interstitial granulomatous dermatitis (IGD) is a poorly understood entity that was regarded by many as belonging to the same spectrum of disease or even synonym with palisaded and neutrophilic granulomatous dermatitis (PNGD). Although IGD and PNGD were usually related to connective tissue disease, mostly rheumatoid arthritis, some patients with typical histologic findings of IGD never develop autoimmune disorders, but they have different underlying conditions, such as metabolic diseases, lymphoproliferative disorders or other malignant tumours. These observations indicate that IGD and PNGD are different disorders with similar manifestations

    Carbon uptake by mature Amazon forests has mitigated Amazon nations' carbon emissions

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    Background: Several independent lines of evidence suggest that Amazon forests have provided a significant carbon sink service, and also that the Amazon carbon sink in intact, mature forests may now be threatened as a result of different processes. There has however been no work done to quantify non-land-use-change forest carbon fluxes on a national basis within Amazonia, or to place these national fluxes and their possible changes in the context of the major anthropogenic carbon fluxes in the region. Here we present a first attempt to interpret results from groundbased monitoring of mature forest carbon fluxes in a biogeographically, politically, and temporally differentiated way. Specifically, using results from a large long-term network of forest plots, we estimate the Amazon biomass carbon balance over the last three decades for the different regions and nine nations of Amazonia, and evaluate the magnitude and trajectory of these differentiated balances in relation to major national anthropogenic carbon emissions. Results: The sink of carbon into mature forests has been remarkably geographically ubiquitous across Amazonia, being substantial and persistent in each of the five biogeographic regions within Amazonia. Between 1980 and 2010, it has more than mitigated the fossil fuel emissions of every single national economy, except that of Venezuela. For most nations (Bolivia, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname) the sink has probably additionally mitigated all anthropogenic carbon emissions due to Amazon deforestation and other land use change. While the sink has weakened in some regions since 2000, our analysis suggests that Amazon nations which are able to conserve large areas of natural and semi-natural landscape still contribute globally-significant carbon sequestration. Conclusions: Mature forests across all of Amazonia have contributed significantly to mitigating climate change for decades. Yet Amazon nations have not directly benefited from providing this global scale ecosystem service. We suggest that better monitoring and reporting of the carbon fluxes within mature forests, and understanding the drivers of changes in their balance, must become national, as well as international, priorities

    Long-term decline of the Amazon carbon sink

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    Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades1, 2, with a substantial fraction of this sink probably located in the tropics3, particularly in the Amazon4. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity5. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale1, 2, and is contrary to expectations based on models6

    A Second-Generation Device for Automated Training and Quantitative Behavior Analyses of Molecularly-Tractable Model Organisms

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    A deep understanding of cognitive processes requires functional, quantitative analyses of the steps leading from genetics and the development of nervous system structure to behavior. Molecularly-tractable model systems such as Xenopus laevis and planaria offer an unprecedented opportunity to dissect the mechanisms determining the complex structure of the brain and CNS. A standardized platform that facilitated quantitative analysis of behavior would make a significant impact on evolutionary ethology, neuropharmacology, and cognitive science. While some animal tracking systems exist, the available systems do not allow automated training (feedback to individual subjects in real time, which is necessary for operant conditioning assays). The lack of standardization in the field, and the numerous technical challenges that face the development of a versatile system with the necessary capabilities, comprise a significant barrier keeping molecular developmental biology labs from integrating behavior analysis endpoints into their pharmacological and genetic perturbations. Here we report the development of a second-generation system that is a highly flexible, powerful machine vision and environmental control platform. In order to enable multidisciplinary studies aimed at understanding the roles of genes in brain function and behavior, and aid other laboratories that do not have the facilities to undergo complex engineering development, we describe the device and the problems that it overcomes. We also present sample data using frog tadpoles and flatworms to illustrate its use. Having solved significant engineering challenges in its construction, the resulting design is a relatively inexpensive instrument of wide relevance for several fields, and will accelerate interdisciplinary discovery in pharmacology, neurobiology, regenerative medicine, and cognitive science

    Effects of Once-Weekly Exenatide on Cardiovascular Outcomes in Type 2 Diabetes.

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    Abstract BACKGROUND: The cardiovascular effects of adding once-weekly treatment with exenatide to usual care in patients with type 2 diabetes are unknown. METHODS: We randomly assigned patients with type 2 diabetes, with or without previous cardiovascular disease, to receive subcutaneous injections of extended-release exenatide at a dose of 2 mg or matching placebo once weekly. The primary composite outcome was the first occurrence of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The coprimary hypotheses were that exenatide, administered once weekly, would be noninferior to placebo with respect to safety and superior to placebo with respect to efficacy. RESULTS: In all, 14,752 patients (of whom 10,782 [73.1%] had previous cardiovascular disease) were followed for a median of 3.2 years (interquartile range, 2.2 to 4.4). A primary composite outcome event occurred in 839 of 7356 patients (11.4%; 3.7 events per 100 person-years) in the exenatide group and in 905 of 7396 patients (12.2%; 4.0 events per 100 person-years) in the placebo group (hazard ratio, 0.91; 95% confidence interval [CI], 0.83 to 1.00), with the intention-to-treat analysis indicating that exenatide, administered once weekly, was noninferior to placebo with respect to safety (P<0.001 for noninferiority) but was not superior to placebo with respect to efficacy (P=0.06 for superiority). The rates of death from cardiovascular causes, fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, hospitalization for heart failure, and hospitalization for acute coronary syndrome, and the incidence of acute pancreatitis, pancreatic cancer, medullary thyroid carcinoma, and serious adverse events did not differ significantly between the two groups. CONCLUSIONS: Among patients with type 2 diabetes with or without previous cardiovascular disease, the incidence of major adverse cardiovascular events did not differ significantly between patients who received exenatide and those who received placebo. (Funded by Amylin Pharmaceuticals; EXSCEL ClinicalTrials.gov number, NCT01144338 .)
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