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1.
Nat Commun ; 12(1): 5693, 2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-34611156

RESUMEN

Peatlands have been drained for land use for a long time and on a large scale, turning them from carbon and nutrient sinks into respective sources, diminishing water regulation capacity, causing surface height loss and destroying biodiversity. Over the last decades, drained peatlands have been rewetted for biodiversity restoration and, as it strongly decreases greenhouse gas emissions, also for climate protection. We quantify restoration success by comparing 320 rewetted fen peatland sites to 243 near-natural peatland sites of similar origin across temperate Europe, all set into perspective by 10k additional European fen vegetation plots. Results imply that rewetting of drained fen peatlands induces the establishment of tall, graminoid wetland plants (helophytisation) and long-lasting differences to pre-drainage biodiversity (vegetation), ecosystem functioning (geochemistry, hydrology), and land cover characteristics (spectral temporal metrics). The Paris Agreement entails the rewetting of 500,000 km2 of drained peatlands worldwide until 2050-2070. A better understanding of the resulting locally novel ecosystems is required to improve planning and implementation of peatland rewetting and subsequent management.


Asunto(s)
Biodiversidad , Restauración y Remediación Ambiental/métodos , Suelo/química , Agua , Humedales , Europa (Continente) , Hidrología
2.
Water Resour Res ; 53(7): 5209-5219, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28919651

RESUMEN

Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage, and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes across time scales, long-term experiments on physical-chemical-biological process interactions, and a focus on connectivity and patterns across spatial scales. It is suggested that these strategies will stimulate new research that coherently addresses the issues across hydrology, soil and agricultural sciences, forest engineering, forest ecology, and geomorphology.

3.
J Environ Manage ; 91(6): 1305-15, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20202739

RESUMEN

Diffuse N losses from agriculture are a major cause of excessive nitrate concentrations in surface and groundwaters. Leaching through the soil is the main pathway of nitrate loss. For environmental management, an anticipatory assessment and monitoring of nitrate leaching risk by indicator (index) approaches is increasingly being used. Although complex Nitrogen Loss Indicator (NLI) approaches may provide more information, relatively simple NLIs may have advantages in many practical situations, for instance, when data availability is restricted. In this study, we tested four simple NLIs to assess their predictive properties: 1. N balance (Nbal); 2. Exchange frequency of soil solution (EF); 3. Potential nitrate concentration in leachate (PNCL); 4. A composite NLI (balance exchange frequency product, BEP). Field data of nitrate leaching from two sites in northeast Germany along with published data from several sites in Germany, Scotland and the USA were utilized. Nbal proved to be a relatively poor indicator of Nloss for the time frame of one year, whereas its prediction accuracy improved for longterm-averaged data. Correlation between calculated EF and experimental data was high for single-year data, whereas it was lower for longterm-averaged data. PNCL gave no significant correlations with measured data and high deviations. The results for BEP were intermediate between those for Nbal and EF. The results suggest that the use of EF is appropriate for assessing N leaching loss for single-year data and specific sites with comparable N input and management practices, whereas for longterm-averaged data, Nbal is better suited. BEP is an appropriate NLI both for single year and longterm data which accounts for source and transport factors and thus is more flexible than source-based Nbal and transport-based EF. However, such simplified NLIs have limitations: 1. The N cycle is not covered completely; 2. Processes in the vadose zone and the aquifer are neglected, 3. Assessment of management factors is restricted.


Asunto(s)
Agricultura , Nitratos/análisis
4.
J Cosmet Laser Ther ; 4(3-4): 73-9, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12623552

RESUMEN

OBJECTIVE: This study was performed in order to evaluate patient satisfaction with epilation using an intense pulsed light source. METHODS: Between 1995 and 2000, 416 patients consulted the authors' practice because of unwanted facial and body hair. A total of 309 patients received treatment with a non-coherent, filtered flashlamp intense pulsed light source. In February 2000, a questionnaire was mailed to each patient and 207 replies were obtained. RESULTS: Overall, 45 (22%) of patients were very satisfied, 93 (45%) were satisfied and 69 (33%) remained unsatisfied with the outcome of light-assisted hair removal. The non-coherent, filtered flashlamp intense pulsed light source satisfactorily removed unwanted dark hair. Hair-free periods from weeks to years could be observed. CONCLUSION: Hair removal by a non-coherent, filtered flashlamp intense pulsed light source is an effective and safe method for long-term epilation of unwanted hair. This technique offers a more reliable and practical solution than any other hair removal method, especially for patients with skin irritation and ingrown hair.


Asunto(s)
Remoción del Cabello/métodos , Hirsutismo/terapia , Satisfacción del Paciente , Fototerapia/métodos , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Encuestas y Cuestionarios
5.
J Contam Hydrol ; 48(3-4): 189-212, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11285931

RESUMEN

Displacement studies on leaching of bromide and two pesticides (atrazine and isoproturon) were conducted under unsaturated steady state flow conditions in 24 small undisturbed soil columns (5.7 cm in diameter and 10 cm long) each collected from two sites differing in soil structure and organic carbon content in North Germany. There were large and irregular variabilities in the characteristics of both soils, as well as in the shapes of breakthrough curves (BTCs) of different columns, including some with early breakthrough and increased tailing, qualitatively indicating the presence of preferential flow. It was estimated that one preferential flow column (PFC) at site A, and four at site B, contributed, respectively to 11% and 58% of the accumulated leached fraction and to more than 80% of the maximum observed standard deviation (SD) in the field-scale concentration and mass flux of pesticides at two sites. The bromide BTCs of two sites were analyzed with the equilibrium convection-dispersion equation (CDE) and a non-equilibrium two-region/mobile-immobile model. Transport parameters of these models for individual BTCs were determined using a curve fitting program, CXTFIT, and by the time moment method. For the CDE based equilibrium model, the mean values of retardation factor, R, considered separately for all columns, PFCs or non-preferential flow columns (NPFCs) were comparable for the two methods; significant differences were observed in the values of dispersion coefficients of two sites using the two estimation methods. It was inferred from the estimated parameters of non-equilibrium model that 5-12% of water at site A, and 12% at site B, was immobile during displacement in NPFCs. The corresponding values for PFCs of two sites were much larger, ranging from 25% to 51% by CXTFIT and from 24% to 72% by the moment method, suggesting the role of certain mechanisms other than immobile water in higher degrees of non-equilibrium in these columns. Peclet numbers in PFCs of both sites were consistently smaller than five, indicating the inadequacy of the non-equilibrium model to incorporate the effect of all forms of non-equilibrium in PFCs. Overall, the BTCs of individual NPFCs, PFCs and of field average concentration at the two sites were better reproduced with parameters obtained from CXTFIT than by the moment method. The moment method failed to capture the peak concentrations in PFCs, but tended to describe the desorption and tail branches of BTCs better than the curve fitting approach.


Asunto(s)
Modelos Teóricos , Compuestos de Fenilurea , Contaminantes del Suelo , Suelo , Contaminantes Químicos del Agua , Atrazina/química , Bromuros/química , Simulación por Computador , Herbicidas/química , Compuestos de Metilurea/química , Solubilidad
6.
Stroke ; 30(11): 2285-90, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10548659

RESUMEN

BACKGROUND AND PURPOSE: The role of 2-dimensional transcranial color-coded sonography (2D-TCCS) as a diagnostic tool in cases of vascular alteration is unquestioned. The skill of the operator, however, may be responsible for some intertrial variability. The clinical value of a new, workstation-based, 3D reconstruction system for TCCS was evaluated in patients with intracranial aneurysms. METHODS: Thirty patients with 30 intracranial aneurysms were investigated (8 men, 22 women; mean+/-SD age 54+/-17 years). The TCCS examinations were performed with a 2-MHz probe using the power mode. The 3D system (3D-Echotech, Germany) consisted of an electromagnet, which induced a low-intensity magnetic field near the head of the patient. A magnetic position sensor was attached to the ultrasound probe and transmitted the spatial orientation of the probe to a workstation, which also received the corresponding 2D-images from the video-port of the duplex machine. The echo contrast enhancer D-galactose (Levovist, Schering, Germany) was used in all patients to improve the signal-to-noise ratio. All patients underwent presurgical digital subtraction angiography (DSA) to demonstrate the aneurysm. RESULTS: Twenty-nine of 30 angiographically proven intracranial aneurysms (97%) were detected by 3D-TCCS. The aneurysmal diameter estimated by DSA ranged from 3 to 16 mm (mean 7. 2+/-3.6 mm). A comparison of the 3 main diameters of each aneurysm revealed a correlation coefficient of 0.95 between DSA and 3D-TCCS. The 3D determination of the aneurysmal size by 2 experienced sonographers correlated with 0.96. CONCLUSIONS: 3D-TCCS is a new, noninvasive method to investigate intracranial aneurysms. The differentiation between artifacts and true changes of the vessel anatomy is much easier in 3D-TCCS than in conventional 2D-TCCS. The new method yields an excellent correlation with the gold standard, DSA. Because the same 3D-TCCS data can be postprocessed by different investigators, it may be possible to improve reproducibility and increase the objectivity of transcranial color-coded duplex sonography.


Asunto(s)
Aneurisma Intracraneal/diagnóstico por imagen , Ultrasonografía Doppler en Color/métodos , Ultrasonografía Doppler Transcraneal/métodos , Angiografía de Substracción Digital , Artefactos , Sistemas de Computación , Medios de Contraste , Fenómenos Electromagnéticos/instrumentación , Femenino , Galactosa , Humanos , Procesamiento de Imagen Asistido por Computador/instrumentación , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Polisacáridos , Reproducibilidad de los Resultados , Procesamiento de Señales Asistido por Computador , Ultrasonografía Doppler en Color/instrumentación , Ultrasonografía Doppler Transcraneal/instrumentación , Grabación en Video
7.
Chirurg ; 67(11): 1114-22, 1996 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-9035946

RESUMEN

Aggressive treatment of patients with severe head injury increases the chance for survival and good functional outcome in most cases. To prevent irreversible cerebral lesions, the key point of treatment is the management of intracranial hypertension caused by intracranial hematomas, brain edema and impaired circulation of cerebrospinal fluid (CSF). Therapeutic standards are surgery of traumatic hematoma, osmotherapy and mild hyperventilation for brain edema, and CSF drainage. In highly elevated intracranial pressure (ICP) administration of barbiturates and forced hyperventilation can be considered.


Asunto(s)
Lesiones Encefálicas/cirugía , Grupo de Atención al Paciente , Lesiones Encefálicas/diagnóstico , Lesiones Encefálicas/mortalidad , Hemorragia Cerebral/diagnóstico , Hemorragia Cerebral/mortalidad , Hemorragia Cerebral/cirugía , Terapia Combinada , Escala de Coma de Glasgow , Humanos , Presión Intracraneal/fisiología , Monitoreo Fisiológico , Seudotumor Cerebral/diagnóstico , Seudotumor Cerebral/mortalidad , Seudotumor Cerebral/cirugía , Tasa de Supervivencia , Resultado del Tratamiento
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