A conceptual model of nitrogen dynamics for the Great Barrier Reef catchments.

Nitrogen (N) from anthropogenic sources has been identified as a major pollutant of the Great Barrier Reef (GBR), Australia. We developed a conceptual framework to synthesise and visualise the fate and transport of N from the catchments to the sea from a literature review. The framework was created to fit managers and policymakers' requirements to reduce N in the GBR catchments. We used this framework to determine the N stocks and transformations (input, sources, and outputs) for ecosystems commonly found in the GBR: rainforests, palustrine wetlands, lakes, rivers (in-stream), mangroves and seagrasses. We included transformations of N such as nitrogen fixation, nitrification, denitrification, mineralisation, anammox, sedimentation, plant uptake, and food web transfers. This model can be applied to other ecosystems to understand the transport and fate of N within and between catchments. Importantly, this approach can guide management actions that attenuate N at different scales and locations within the GBR ecosystems. Finally, when combined with local hydrological modelling, this framework can be used to predict outcomes of management activities.

Nitrogen processing by treatment wetlands in a tropical catchment dominated by agricultural landuse.

Agriculture is a major contributor to marine nitrogen pollution, and treatment wetlands can be a strategy to reduce it. However, few studies have assessed the potential of treatment wetlands to mitigate nitrogen pollution in tropical regions. We quantify the nitrogen removal rates of four recently constructed treatment wetlands in tropical Australia. We measured denitrification potential (Dt), the inflow-outflow of nutrients, and tested whether the environment in these tropical catchments is favourable for nitrogen removal. Dt was detected in three of the four systems with rates between 2.0 and 12.0 mg m-2 h-1; the highest rates were measured in anoxic soils (ORP -100 to 300 mV) that were rich in carbon and nitrogen (>2% and >0.2%, respectively). The highest nitrogen removal rates were measured when NO3--N concentrations were >0.4 mg L-1 and when water flows were slow. Treatment wetlands in tropical regions can deliver high removal rates of nitrogen and other pollutants when adequately managed. This strategy can reduce nutrient loads and their impacts on sensitive coastal zones such as the Great Barrier Reef.

Mangrove sinkholes (cenotes) of the Yucatan Peninsula, a global hotspot of carbon sequestration.

Mangroves are among the most carbon-dense ecosystems on the planet. The capacity of mangroves to store and accumulate carbon has been assessed and reported at regional, national and global scales. However, small-scale sampling is still revealing 'hot spots' of carbon accumulation. This study reports one of these hotspots, with one of the largest-recorded carbon stocks in mangroves associated with sinkholes (cenotes) in the Yucatan Peninsula, Mexico. We assessed soil organic carbon (SOC) stocks, sequestration rates and carbon origin of deep peat soils (1 to 6 m). We found massive amounts of SOC up to 2792 Mg C ha-1, the highest value reported in the literature so far. This SOC is primarily derived from highly preserved mangrove roots and has changed little since its deposition, which started over 3220 years ago (±30 BP). Most cenotes are owned by Mayan communities and are threatened by increased tourism and the resulting extraction and pollution of groundwater. These hot spots of carbon sequestration, albeit small in area, require adequate protection and could provide valuable financial opportunities through carbon-offsetting mechanisms and other payments for ecosystem services.

Soil nitrogen accumulation, denitrification potential, and carbon source tracing in bioretention basins.

Bioretention basins are one of the most commonly used green stormwater features, with the potential to accumulate significant levels of nitrogen (N) in their soil and to permanently remove it through denitrification. Many studies have investigated the N removal potential of bioretention basins through the assessment of inflow and outflow concentrations. However, their long-term N removal through soil accumulation and denitrification potential is less known. This study investigated the temporal variation of total N (TN) accumulation and denitrification potential in soils of 25 bioretention basins within a 13-year soil chronosequence, in a subtropical climate in Australia. The denitrification potential of a subset of seven bioretention basins was investigated in accompaniment with nutrient and soil characteristics. Additionally, stable isotopes (δ13C and δ15N) were used to assess temporal changes in the soil composition as well as to identify the sources of carbon (C) into these basins. Over 13 years of operation, TN accumulated faster in the top 5 cm of soil than deeper soils. Soil TN density was highest in the top 5 cm with an average of 1.4 kg N m-3, which was about two times higher than deeper soils. Site age and soil texture were the best predictors of soil TN density and denitrification (1 to 9.7 mg N m-2 h-1). The isotope values were variable among basins. Low δ15N values in young basins (-1.02‰) suggested fixation as the main source of N, while older basins had higher δ15N, indicating higher denitrification. Bioretention plants were the primary source of soil C; although the occurrence of soil amendment also contributed to the C pool. To improve the performance of these bioretention basins, we recommend increasing vegetation at initial years after construction, and enhancing more frequent anaerobic conditions in the high soil profile. These two conditions can improve denitrification potential, and thus the performance of these basins for improving water quality.

A systematic review of the indirect and social costs studies in fragility fractures.

Fragility fractures (FF) are the main clinical consequence of osteoporosis. FF lead to a loss in quality of life (QL), increased dependency and higher costs due to loss of productivity. Despite this, very few studies have been performed about the indirect or social costs of FF. The objective of this review was to systematically synthesize published evidence regarding indirect costs of FF. We conducted a systematic literature review of empirical studies published as peer review papers between 1998 and 2019. A total of 295 papers were found about costs and osteoporosis. After an iterative process, only 16 papers fit the criteria of selection. Despite the important consequences for QL, only seven studies have included research of the issue and only one about dependency. Treatments are cost-effective, but adherence is low. Multiple fractures, older age and low socioeconomic profile imply higher costs. Most studies are performed using the human capital methodology. The main two variables are loss of productivity and absenteeism. Most of the people included in the samples are out of the active population. Those studies that include a follow-up period vary in a range between 3 months and 2 years. Depending on sample and methodology, the indirect costs (IC) are between 2 and 50%. The direct costs associated with FF generally far outweigh the IC. There is a lack of studies about the effects of treatments and adherence and about the dependency system. The changing role of women in coming generations will increase indirect costs.

Avoided emissions and conservation of scrub mangroves: potential for a Blue Carbon project in the Gulf of California, Mexico.

Mangroves are considered ideal ecosystems for Blue Carbon projects. However, because of their short stature, some mangroves ('scrub' mangroves, less than 2 m) do not fulfil the current definition of 'forests', which makes them ineligible for emission reduction programmes such as REDD+. Short stature mangroves can be the dominant form of mangroves in arid and nutrient-poor landscapes, and emissions from their deforestation and degradation could be substantial. Here, we describe a Blue Carbon project in the Gulf of California, Mexico, to illustrate that projects that avoid emissions from deforestation and degradation could provide financial resources to protect mangroves that cannot be included in other emission reduction programmes. The goal of the project is to protect 16 058 ha of mangroves through conservation concessions from the Mexican Federal Government. The cumulative avoided emissions of the project are 2.84 million Mg CO2 over 100 years, valued at $US 426 000 per year (US$15 per Mg CO2 in the California market). The funds could be used for community-based projects that will improve mangrove management, such as surveillance, eradication of invasive species, rehabilitation after tropical storms and environmental education. The strong institutional support, secure financial status, community engagement and clear project boundaries provide favourable conditions to implement this Blue Carbon project. Financial resources from Blue Carbon projects, even in mangroves of short stature, can provide substantial resources to enhance community resilience and mangrove protection.

Selecting cost-effective areas for restoration of ecosystem services.

Selection of areas for restoration should be based on cost-effectiveness analysis to attain the maximum benefit with a limited budget and overcome the traditional ad hoc allocation of funds for restoration projects. Restoration projects need to be planned on the basis of ecological knowledge and economic and social constraints. We devised a novel approach for selecting cost-effective areas for restoration on the basis of biodiversity and potential provision of 3 ecosystem services: carbon storage, water depuration, and coastal protection. We used Marxan, a spatial prioritization tool, to balance the provision of ecosystem services against the cost of restoration. We tested this approach in a mangrove ecosystem in the Caribbean. Our approach efficiently selected restoration areas that at low cost were compatible with biodiversity targets and that maximized the provision of one or more ecosystem services. Choosing areas for restoration of mangroves on the basis carbon storage potential, largely guaranteed the restoration of biodiversity and other ecosystem services.

Direct estimate of 1:1 stoichiometry of K(+)-Cl(-) cotransport in rabbit erythrocytes.

This work was undertaken to obtain a direct measure of the stoichiometry of Na(+)-independent K(+)-Cl(-) cotransport (KCC), with rabbit red blood cells as a model system. To determine whether (86)Rb(+) can be used quantitatively as a tracer for KCC, (86)Rb(+) and K(+) effluxes were measured in parallel after activation of KCC with N-ethylmaleimide (NEM). The rate constant for NEM-stimulated K(+) efflux into isosmotic NaCl was smaller than that for (86)Rb(+) by a factor of 0.68 +/- 0.11 (SD, n = 5). This correction factor was used in all other experiments to calculate the K(+) efflux from the measured (86)Rb(+) efflux. To minimize interference from the anion exchanger, extracellular Cl(-) was replaced with SO, and 4,4'-diisothiocyanothiocyanatodihydrostilbene-2,2'-disulfonic acid was present in the flux media. The membrane potential was clamped near 0 mV with the protonophore 2,4-dinitrophenol. The Cl(-) efflux at 25 degrees C under these conditions is approximately 100,000-fold smaller than the uninhibited Cl(-)/Cl(-) exchange flux and is stimulated approximately 2-fold by NEM. The NEM-stimulated (36)Cl(-) flux is inhibited by okadaic acid and calyculin A, as expected for KCC. The ratio of the NEM-stimulated K(+) to Cl(-) efflux is 1.12 +/- 0.26 (SD, n = 5). We conclude that K(+)-Cl(-) cotransport in rabbit red blood cells has a stoichiometry of 1:1.

[Perspectives of laparoscopy in cardia and gastric surgery]. / A laparoszkópia útkeresése a cardiatáj és a gyomor sebészetében.

The authors have made 171 laparoscopic operations in the gastro-esophageal region during the past three and a half years. They have used the achievement of the minimal invasive surgery mainly in the treatment of functional diseases of the gastro-esophageal junction. Besides the hiatal reconstruction and antireflux procedures (142), endoscopic assisted cysto-gastrostomy (7), endoscopic assisted double-lifting gastric wall resection (5), cardiomyotomy (4), Graham suture of perforated duodenal ulcer (4) and enucleation of gastric wall leiomyoma (2) has been performed. There was no postoperative death, the rate of conversion was altogether 4.7% (8/171) while there was no need for reoperation in the early postoperative period.

A comparative study with oral nifedipine, intravenous nimodipine, and magnesium sulfate in postoperative analgesia.

UNLABELLED: We tested the ability of two L-type calcium channel blockers (nifedipine and nimodipine) and the N-methyl D-aspartate natural antagonist magnesium to decrease morphine requirements and pain in the postoperative period in 92 patients undergoing elective colorectal surgery. In a randomized, double-blinded study, patients were assigned to one of four groups. The control group received placebo. The nifedipine group received 60 mg of oral nifedipine. The magnesium group received an initial dose of 30 mg/kg followed by 10 mg x kg(-1) x h(-1) of magnesium sulfate over 20 h. The nimodipine group received 30 microg x kg(-1) x h(-1) of nimodipine over 20 h. Postoperative morphine consumption was assessed for 48 h. Pain at rest and pain on movement were assessed up to the fifth day postsurgery. There were no differences among groups in postoperative morphine consumption at 12 and 24 h. The nifedipine group consumed more morphine than the control and nimodipine groups during 24-48 h. Pain at rest scores were higher at 16 and 24 h in the nifedipine group than in the other three groups. Pain on movement scores were lower at 72 h in the nimodipine group than in the control and nifedipine groups. In conclusion, the perioperative application of oral nifedipine, IV nimodipine, or IV magnesium sulfate failed to decrease postoperative morphine requirements after colorectal surgery. IMPLICATIONS: The increase of intracellular calcium plays a key role in spinal transmission of pain and in the establishment of central sensitization. We examined the effects of nifedipine, nimodipine, and magnesium sulfate in postoperative analgesia after colorectal surgery. We found no differences in morphine consumption with the administration of each drug alone.

[Common variable immunodeficiency associated with autoimmune thrombocytopenia: anesthetic management]. / Inmunodeficiencia variable común asociada a trombopenia autoinmune: manejo anestésico.

A 44-year-old man diagnosed of common variable immunodeficiency associated with thrombopenia due to autoimmunity required anesthesia for anal fissure repair and hemorrhoidectomy. Hemostatic complications developed after surgery, with extreme thrombopenia (1,000 platelets/pl) and analytical changes that necessitated administration of six units of platelets from apheresis, as well as immunoglobulins, antifibrinolytic agents (e-aminocaproic acid) and granulocytic colony stimulating factors. Anesthesia for such patients is reviewed, with emphasis on careful management of the airways, preparation of sufficient material for surgery (rapid transfusion equipment, large caliber intravenous catheters, sterile material) and orientation of anesthetic technique toward general anesthesia through a laryngeal mask.

Characterization of oxalate transport by the human erythrocyte band 3 protein.

This paper describes characteristics of the transport of oxalate across the human erythrocyte membrane. Treatment of cells with low concentrations of H2DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonate) inhibits Cl(-)-Cl- and oxalate-oxalate exchange to the same extent, suggesting that band 3 is the major transport pathway for oxalate. The kinetics of oxalate and Cl- self-exchange fluxes indicate that the two ions compete for a common transport site; the apparent Cl- affinity is two to three times higher than that of oxalate. The net exchange of oxalate for Cl-, in either direction, is accompanied by a flux of H+ with oxalate, as is also true of net Cl(-)-SO4(2-) exchange. The transport of oxalate, however, is much faster than that of SO4(2-) or other divalent anions. Oxalate influx into Cl(-)-containing cells has an extracellular pH optimum of approximately 5.5 at 0 degrees C. At extracellular pH below 5.5 (neutral intracellular pH), net Cl(-)-oxalate exchange is nearly as fast as Cl(-)-Cl- exchange. The rapid Cl(-)-oxalate exchange at acid extracellular pH is not likely to be a consequence of Cl- exchange for monovalent oxalate (HOOC-COO-; pKa = 4.2) because monocarboxylates of similar structure exchange for Cl- much more slowly than does oxalate. The activation energy of Cl(-)-oxalate exchange is about 35 kCal/mol at temperatures between 0 and 15 degrees C; the rapid oxalate influx is therefore not a consequence of a low activation energy. The protein phosphatase inhibitor okadaic acid has no detectable effect on oxalate self-exchange, in contrast to a recent finding in another laboratory (Baggio, B., L. Bordin, G. Clari, G. Gambaro, and V. Moret. 1993. Biochim. Biophys. Acta. 1148:157-160.); our data provide no evidence for physiological regulation of anion exchange in red cells.

Encuesta de salud de refugiados guatemaltecos en la frontera sur de México / Health surveys of Guatemalan refugees along the Southern border of Mexico

En noviembre de 1983, se llevó a cabo una investigación sobre las condiciones de vida y la frecuencia de enfermedades transmisibles y de desnutrición en ocho campamentos de refugiados guatemaltecos y en tres comunidades rurales mexicanas en la frontera sur de México, con objeto de valorar si ha habido cambios en el perfil epidemiológico de la población mexicana de esa zona, debidos al impacto de la migración. Por muestreo aleatorio se seleccionaron 158 familias de refugiados guatemaltecos (955 individuos) y 125 familias de la población rural mexicana (718 individuos). Se aplicó un cuestionario, en el cual se registraron la composición de la familia y las características de las viviendas y se investigaron las enfermedades infecciosas mediante interrogatorio y exploración física detallada, registro de peso y talla, y toma de muestras de sangre y heces para búsqueda de Plasmodium y de parásitos intestinales. En ambos grupos de población las condiciones de vida eran deficientes, la mayoría de las viviendas carecían de agua entubada y las familias vivían en condiciones de hacinamiento. Se encontró una alta prevalencia de enfermedades infecciosas, en especial las transmitidas por contacto directo; 2,3% de los frotis de sangre fueron positivos para Plasmodium y la cobertura de vacunación de los niños menores de cinco años fue muy baja. Más del 80% de los individuos presentaron parasitosis intestinal y aproximadamente 75% de la población tenía algún grado de desnutrición. Se concluye que no ha habido un impacto importante de un grupo sobre otro, sino que las enfermedades que aquejan tanto a los refugiados guatemaltecos como a la población rural mexicana son las que prevalecen en la zona geográfica y están subordinadas a las condiciones socioeconómicas; por consiguiente, las medidas de control que se apliquen deberán incluir a ambos grupos de población

Encuesta de salud de refugiados guatemaltecos en la frontera sur de Mexico / Health surveys of Guatemalan refugees along the Southern border of Mexico

In november 1983 a study was done of living conditions and the frequency of communicable diseases and malnutrition in eight camps for Guatemalan refugees and three rural Mexican communities along the southern border of Mexico. The purpose of the study was to determine what changes the influx of refugees might have brought about in the epidemiological profile of the Mexican population in that border zone. A study group of 158 Guatemalan refugee families (955 individuals) and 125 rural Mexican families (718 individuals) was selected by random sampling. A questionnaire was used to record the composition of the family and the characteristics of the dwellings, and the presence of infectious diseases was investigated by interviews, thorough physical examinations, recording of weights and heights, and examination of blood and feces for the presence of Plasmodium and intestinal parasites. In both population groups, living conditions were poor: most of the dwellings lacked running water and were overcrowed. The prevalence of infectious diseases, especially those transmitted by direct contact,was found to be high; 2.3 per cent of all blood smears tested positive for Plasmodium, and the vaccination coverage of children under 5 was very low. Intestinal parasitosis was found in more than 80 per cent of the individuals, and about 75 per cent of them suffered from some degree of malnutrition