313 research outputs found
Global patterns of cropland use intensity
No full textThis study presents a global scale analysis of cropping intensity, crop duration and fallow land extent computed by using the global dataset on monthly irrigated and rainfed crop areas MIRCA2000. MIRCA2000 was mainly derived from census data and crop calendars from literature. Global cropland extent was 16 million km2 around the year 2000 of which 4.4 million km2 (28%) was fallow, resulting in an average cropping intensity of 0.82 for total cropland extent and of 1.13 when excluding fallow land. The lowest cropping intensities related to total cropland extent were found for Southern Africa (0.45), Central America (0.49) and Middle Africa (0.54), while highest cropping intensities were computed for Eastern Asia (1.04) and Southern Asia (1.0). In remote or arid regions where shifting cultivation is practiced, fallow periods last 3–10 years or even longer. In contrast, crops are harvested two or more times per year in highly populated, often irrigated tropical or subtropical lowlands where multi-cropping systems are common. This indicates that intensification of agricultural land use is a strategy that may be able to significantly improve global food security. There exist large uncertainties regarding extent of cropland, harvested crop area and therefore cropping intensity at larger scales. Satellite imagery and remote sensing techniques provide opportunities for decreasing these uncertainties and to improve the MIRCA2000 inventory
Groundwater use for irrigation - a global inventory
No full textIrrigation is the most important water use sector accounting for about 70% of the global freshwater withdrawals and 90% of consumptive water uses. While the extent of irrigation and related water uses are reported in statistical databases or estimated by model simulations, information on the source of irrigation water is scarce and very scattered. Here we present a new global inventory on the extent of areas irrigated with groundwater, surface water or non-conventional sources, and we determine the related consumptive water uses. The inventory provides data for 15 038 national and sub-national administrative units. Irrigated area was provided by census-based statistics from international and national organizations. A global model was then applied to simulate consumptive water uses for irrigation by water source. Globally, area equipped for irrigation is currently about 301 million ha of which 38% are equipped for irrigation with groundwater. Total consumptive groundwater use for irrigation is estimated as 545 km3 yr−1, or 43% of the total consumptive irrigation water use of 1 277 km3 yr−1. The countries with the largest extent of areas equipped for irrigation with groundwater, in absolute terms, are India (39 million ha), China (19 million ha) and the United States of America (17 million ha). Groundwater use in irrigation is increasing both in absolute terms and in percentage of total irrigation, leading in places to concentrations of users exploiting groundwater storage at rates above groundwater recharge. Despite the uncertainties associated with statistical data available to track patterns and growth of groundwater use for irrigation, the inventory presented here is a major step towards a more informed assessment of agricultural water use and its consequences for the global water cycle
Impact of water withdrawals from groundwater and surface water on continental water storage variations
No full textHumans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 km3/year during 1998–2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 km3/year during 1998–2002. It is the sum of the net abstraction of 250 km3/year of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/year of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on groundwater table observations, and with estimates of total water storage variations from the GRACE satellites mission. Due to the difficulty in estimating area-averaged seasonal groundwater storage variations from point observations of groundwater levels, it is uncertain whether WaterGAP underestimates actual variations or not. We conclude that WaterGAP possibly overestimates water withdrawals in the High Plains aquifer where impact of human water use on water storage is readily discernible based on WaterGAP calculations and groundwater observations. No final conclusion can be drawn regarding the possibility of monitoring water withdrawals in the High Plains aquifer using GRACE. For the less intensively irrigated Mississippi basin, observed and modeled seasonal groundwater storage reveals a discernible impact of water withdrawals in the basin, but this is not the case for total water storage such that water withdrawals at the scale of the whole Mississippi basin cannot be monitored by GRACE
Complete hypogonadotropic hypogonadism associated with a novel inactivating mutation of the gonadotropin-releasing hormone receptor
No full textIn this study, we describe a patient with a phenotype of complete hypogonadotropic hypogonadism who presented primary failure of pulsatile GnRH therapy, but responded to exogenous gonadotropin administration. This patient bore a novel point mutation (T for A) at codon 168 of the gene encoding the GnRH receptor (GnRH-R), resulting in a serine to arginine change in the fourth transmembrane domain of the receptor. This novel mutation was present in the homozygous state in the patient, whereas it was in the heterozygous state in both phenotypically normal parents. When introduced into the complementary DNA coding for the GnRH-R, this mutation resulted in the complete loss of the receptor-mediated signaling response to GnRH. In conclusion, we report the first mutation of the GnRH-R gene that can induce a total loss of function of this receptor and is associated with a phenotype of complete hypogonadotropic hypogonadism
Global-scale analysis of satellite-derived time series of naturally inundated areas as a basis for floodplain modeling
No full textFloodplains play an important role in the terrestrial water cycle and are very important for biodiversity. Therefore, an improved representation of the dynamics of floodplain water flows and storage in global hydrological and land surface models is required. To support model validation, we combined monthly time series of satellite-derived inundation areas (Papa et al., 2010) with data on irrigated rice areas (Portmann et al., 2010). In this way, we obtained global-scale time series of naturally inundated areas (NIA), with monthly values of inundation extent during 1993–2004 and a spatial resolution of 0.5°. For most grid cells (0.5°×0.5°), the mean annual maximum of NIA agrees well with the static open water extent of the Global Lakes and Wetlands database (GLWD) (Lehner and Döll, 2004), but in 16% of the cells NIA is larger than GLWD. In some regions, like Northwestern Europe, NIA clearly overestimates inundated areas, probably because of confounding very wet soils with inundated areas. In other areas, such as South Asia, it is likely that NIA can help to enhance GLWD. NIA data will be very useful for developing and validating a floodplain modeling algorithm for the global hydrological model WGHM. For example, we found that monthly NIAs correlate with observed river discharges
A new method for reconstruction of the external ear canal in congenital aural atresia - Free skin graft prepared from penile prepuce
No full text3rd International Symposium on Transplants and Implants in Otology -- JUN 10-14, 1995 -- BORDEAUX, FRANCEA new reconstruction technique that can be performed in the treatment of male patients with congenital aural atresia is presented. In a six-year-old boy with unilateral agenesis of the external auditory canal and middle ear malformation, circumcision was carried out at the same time as the ear surgery, and a preputial graft prepared in a special manner was used in the reconstruction of the external auditory canal. Complete epithelization of the external auditory canal and a wide meatus was obtained with-a hearing gain of 45-50 dB in four months. By keeping the Merocel packing in the external auditory canal for 20 days, seven consecutive dressings were changed after the operation
The effects of hydrocortisone on systemic arterial blood pressure and urinary protein excretion in dogs.
No full textBACKGROUND: Hypertension and proteinuria are commonly recognized in dogs with spontaneous hypercortisolism. There is, however, little information regarding the effect of exogenous glucocorticoids on blood pressure (BP) and proteinuria and whether these changes are reversible. HYPOTHESIS: Hydrocortisone administration increases systemic BP and urinary protein excretion, and these effects are reversible after hydrocortisone withdrawal. Animals: Six control dogs and 6 dogs treated with hydrocortisone. METHODS: BP, urine protein : creatinine ratio (UPC), microalbuminuria (MALB), urine albumin : creatinine ratio (UAC), and urine gel electrophoresis were evaluated before, during, and after administration of hydrocortisone (8 mg/kg PO q12h for 12 weeks) or placebo. RESULTS: BP and UPC increased substantially during hydrocortisone administration from 123 mmHg (range 114-136 mmHg) and 0.17 (0.15-0.28) to a maximum of 143 mmHg (128-148 mmHg) and 0.38 (0.18-1.78), respectively, on day 28. MALB developed in 4 dogs and UAC significantly increased in all dogs during hydrocortisone administration with the maximum on day 84. Both increases in BP and proteinuria were reversible and completely resolved within 1 month after stopping hydrocortisone administration. SDS-AGE revealed the proteinuria to be primarily albuminuria with a pronounced increase during hydrocortisone treatment. Furthermore, a protein of 25-30 kDa was found in male dogs, identified by mass spectrometry to be arginine esterase, the major secretory prostatic protein. CONCLUSIONS AND CLINICAL IMPORTANCE: Long-term hydrocortisone treatment results in significant but only mild increases in systemic BP and urinary protein excretion, which are both reversible within 1 month after discontinuation of hydrocortisone
Impact of climate change on renewable groundwater resources : assessing the benefits of avoided greenhouse gas emissions using selected CMIP5 climate projections
No full textReduction of greenhouse gas (GHG) emissions to minimize climate change requires very significant societal effort. To motivate this effort, it is important to clarify the benefits of avoided emissions. To this end, we analysed the impact of four emissions scenarios on future renewable groundwater resources, which range from 1600 GtCO2 during the 21st century (RCP2.6) to 7300 GtCO2 (RCP8.5). Climate modelling uncertainty was taken into account by applying the bias-corrected output of a small ensemble of five CMIP5 global climate models (GCM) as provided by the ISI-MIP effort to the global hydrological model WaterGAP. Despite significant climate model uncertainty, the benefits of avoided emissions with respect to renewable groundwater resources (i.e. groundwater recharge (GWR)) are obvious. The percentage of projected global population (SSP2 population scenario) suffering from a significant decrease of GWR of more than 10% by the 2080s as compared to 1971–2000 decreases from 38% (GCM range 27–50%) for RCP8.5 to 24% (11–39%) for RCP2.6. The population fraction that is spared from any significant GWR change would increase from 29% to 47% if emissions were restricted to RCP2.6. Increases of GWR are more likely to occur in areas with below average population density, while GWR decreases of more than 30% affect especially (semi)arid regions, across all GCMs. Considering change of renewable groundwater resources as a function of mean global temperature (GMT) rise, the land area that is affected by GWR decreases of more than 30% and 70% increases linearly with global warming from 0 to 3 ° C. For each degree of GMT rise, an additional 4% of the global land area (except Greenland and Antarctica) is affected by a GWR decrease of more than 30%, and an additional 1% is affected by a decrease of more than 70%
Die Verordnung (EG) 805/2004 zur Einführung eines europäischen Vollstreckungstitels für unbestrittene Forderungen (EuVTVO) und ihre Konsequenzen für den Schuldnerschutz
No full textMit der EuVTVO wird zur Vereinfachung und Beschleunigung der Vollstreckung ausländischer Titel innerhalb der europäischen Gemeinschaft der Eu-Vollstreckungstitel eingeführt. Bei dieser Verordnung handelt es sich um eine konsequente Fortsetzung des bereits mit der EuGVVO begonnenen Ansatzes zur Integration eines grenzüberschreitenden Vollstreckungstitels in die jeweiligen nationalen Rechtssysteme. Die herausragende Neuerung durch die EuVTVO stellen die Abschaffung der Vollstreckbarerklärung im Vollstreckungsstaat und der damit verbundene Wegfall der wesentlichen Anerkennungs- und Vollstreckungshindernisse dar. Die Einführung der EuVTVO und damit die Abschaffung des Exequaturverfahrens im Vollstreckungsstaat für unbestrittene Forderungen ist ein weiterer Schritt zur Verbesserung und Vereinfachung der Anerkennung und Vollstreckung gerichtlicher und außergerichtlicher Entscheidung in Zivil- und Handelssachen
Die Verordnung (EG) 805/2004 zur Einführung eines europäischen Vollstreckungstitels für unbestrittene Forderungen (EuVTVO) und ihre Konsequenzen für den Schuldnerschutz
No full textMit der EuVTVO wird zur Vereinfachung und Beschleunigung der Vollstreckung ausländischer Titel innerhalb der europäischen Gemeinschaft der Eu-Vollstreckungstitel eingeführt. Bei dieser Verordnung handelt es sich um eine konsequente Fortsetzung des bereits mit der EuGVVO begonnenen Ansatzes zur Integration eines grenzüberschreitenden Vollstreckungstitels in die jeweiligen nationalen Rechtssysteme. Die herausragende Neuerung durch die EuVTVO stellen die Abschaffung der Vollstreckbarerklärung im Vollstreckungsstaat und der damit verbundene Wegfall der wesentlichen Anerkennungs- und Vollstreckungshindernisse dar. Die Einführung der EuVTVO und damit die Abschaffung des Exequaturverfahrens im Vollstreckungsstaat für unbestrittene Forderungen ist ein weiterer Schritt zur Verbesserung und Vereinfachung der Anerkennung und Vollstreckung gerichtlicher und außergerichtlicher Entscheidung in Zivil- und Handelssachen
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