RESUMEN
The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ± 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55 ± 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12-17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon-climate feedback that could accelerate climate change.
Asunto(s)
Atmósfera/química , Ciclo del Carbono , Carbono/análisis , Geografía , Calentamiento Global , Suelo/química , Bases de Datos Factuales , Ecosistema , Retroalimentación , Modelos Estadísticos , Reproducibilidad de los Resultados , TemperaturaRESUMEN
The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization.
Asunto(s)
Bosques , Mapeo Geográfico , Árboles/crecimiento & desarrollo , Ecología/estadística & datos numéricos , Ecosistema , Agricultura Forestal/estadística & datos numéricos , Densidad de Población , Reproducibilidad de los ResultadosRESUMEN
AIMS: Marked hyperglycaemia is common following betamethasone administration in women with gestational diabetes (GDM), and may contribute to neonatal hypoglycaemia. Validated protocols to deliver glycaemic stability following betamethasone are lacking. We hypothesized that an intravenous insulin (IVI) protocol for pregnancy-specific glycaemic targets (Pregnancy-IVI) would achieve greater at-target glycaemic control than a generic adult intravenous insulin protocol (Adult-IVI), and may reduce neonatal hypoglycaemia. METHODS: A retrospective cohort study of the performance Adult-IVI and Pregnancy-IVI following betamethasone in GDM, sequentially implemented at a tertiary hospital, without change in indication for IVI. Cases were identified by electronic record search. Primary outcome was percentage of on-IVI time with at-target glycaemia [blood glucose level (BGL) 3.8-7 mmol/l]. Secondary outcomes were time with critical hyperglycaemia (BGL > 10 mmol/l), occurrence of maternal hypoglycaemia (BGL < 3.8 mmol/l), and incidence of neonatal hypoglycaemia (BGL ≤ 2.5 mmol/l) if betamethasone was administered within 48 h of birth. RESULTS: The cohorts comprised 151 women (Adult-IVI n = 86; Pregnancy-IVI n = 65). The primary outcome was 68% time-at-target [95% confidence interval (CI) 64-71%) for Pregnancy-IVI compared with 55% (95% CI 50-60%) for Adult-IVI (P = 0.0002). Critical maternal hyperglycaemia (0% vs. 2%, P = 0.02) and hypoglycaemia (2% vs. 12%, P = 0.02) were both lower with Pregnancy-IVI than Adult-IVI. Neonatal hypoglycaemia was less common after Pregnancy-IVI (29%) than after Adult-IVI (54%, P = 0.03). A multiple logistic regression model adjusting for potential confounders gave an odds ratio for neonatal hypoglycaemia with Pregnancy-IVI of 0.27 (95% CI 0.10-0.76, P = 0.01). CONCLUSIONS: An IVI protocol designed for pregnancy effectively controlled maternal hyperglycaemia following betamethasone administration in GDM. This is the first intervention to show a reduction in betamethasone-associated neonatal hypoglycaemia, linked with optimum maternal glycaemic control.
Asunto(s)
Betametasona/efectos adversos , Diabetes Gestacional/tratamiento farmacológico , Glucocorticoides/efectos adversos , Hipoglucemia/prevención & control , Hipoglucemiantes/administración & dosificación , Insulina/administración & dosificación , Adulto , Betametasona/administración & dosificación , Glucemia/efectos de los fármacos , Protocolos Clínicos , Diabetes Gestacional/sangre , Femenino , Glucocorticoides/administración & dosificación , Humanos , Hiperglucemia/inducido químicamente , Recién Nacido , Infusiones Intravenosas , Embarazo , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
AIM: Overweight and obesity are frequently reported in young persons with type 1 diabetes, however its relative magnitude in comparison to the general population is not well understood. This study compared the prevalence of overweight and obesity in young persons with type 1 diabetes to a reference population and explored possible associated factors, including gender, age, HbA1c , insulin regimen, age at diagnosis, diabetes duration, socio-economic status and cardiovascular disease risk factors. METHODS: A cross-sectional review was undertaken of data collected from youth (3-17 years) in 2016 and young adults (18-30 years) in 2015 with a diagnosis of type 1 diabetes for > 3 months attending diabetes centres in Newcastle, Australia. Rates of overweight and obesity were compared with matched population survey results. RESULTS: Data from 308 youth and 283 young adults were included. In girls, significantly higher prevalence of overweight and obesity were seen in the 5-8 (43% vs. 18%), 13-16 (41% vs. 27%), 18-24 (46% vs. 34%) and 25-30 (60% vs. 43%) years age groups; whereas in boys increased prevalence was observed in the 5-8 years age group only (41% vs. 18%). Rates of overweight and obesity increased with age across sexes. In youth, BMI standard deviation score was correlated with socio-economic status, insulin regimen, blood pressure and blood lipids (P < 0.05). In adults, BMI was positively associated with blood pressure, and longer diabetes duration (P < 0.02). CONCLUSIONS: Overweight and obesity are over-represented in young persons with type 1 diabetes, particularly girls. As overweight is associated with other cardiovascular disease markers early intervention is paramount.
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Diabetes Mellitus Tipo 1/epidemiología , Angiopatías Diabéticas/epidemiología , Hipoglucemiantes/uso terapéutico , Insulina/uso terapéutico , Obesidad/epidemiología , Sobrepeso/epidemiología , Adolescente , Adulto , Factores de Edad , Australia/epidemiología , Presión Sanguínea , Niño , Preescolar , Estudios Transversales , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/fisiopatología , Angiopatías Diabéticas/etiología , Angiopatías Diabéticas/fisiopatología , Femenino , Hemoglobina Glucada , Humanos , Insulina/sangre , Masculino , Obesidad/complicaciones , Obesidad/fisiopatología , Sobrepeso/complicaciones , Sobrepeso/fisiopatología , Cooperación del Paciente , Prevalencia , Vigilancia de Guardia , Factores Sexuales , Factores Socioeconómicos , Adulto JovenRESUMEN
AIMS: To assess the relationship between insulin resistance (IR), retinopathy and maculopathy in young adults with Type 1 diabetes mellitus. METHODS: A cross-sectional study at a regional Australian tertiary hospital. Retinal pathology, assessed by colour fundus photography, was correlated with two surrogate measures of IR: estimated Glucose Disposal Rate (eGDR) and Insulin Sensitivity Score (ISS), where lower scores reflect greater IR. RESULTS: 107 patients were recruited, with mean age 24.7years, 53% male, and mean duration of disease 10.8years. Mean eGDR scores (5.6vs 8.0 p<0.001) and ISS (4.7vs 7.9, p<0.001) were lower in subjects having at least moderate non-proliferative diabetic retinopathy (NPDR; relative to nil/mild-NPDR). Similarly, mean eGDR (4.2vs 6.2, p=0.001) and ISS (3.8vs 6.1, p=0.003) were lower in patients with maculopathy. Multivariate logistic regression modelling was used to control for confounding. For retinopathy severity, a unit increase in eGDR or ISS (representing lower IR) was associated with a 50% decrease in odds of moderate-NPDR or worse (eGDR OR 0.5, 95%CI 0.32-0.77, p=0.002; ISS OR 0.49, 95%CI 0.29-0.84, p=0.01). A unit increase in eGDR or ISS was associated with a 46-56% decrease in odds of maculopathy (eGDR OR 0.54, 95%CI 0.37-0.81, p=0.003; ISS OR 0.44, 95%CI 0.22-0.88, p=0.02). CONCLUSIONS: IR correlates with more severe retinopathy in young adults with Type 1DM. This is the first description of a correlation between IR and maculopathy in Type 1DM, warranting further evaluation. Prospective studies examining whether reducing IR can improve microvascular complications are required.
Asunto(s)
Diabetes Mellitus Tipo 1/complicaciones , Retinopatía Diabética/etiología , Glucosa/metabolismo , Degeneración Macular/etiología , Adolescente , Adulto , Estudios Transversales , Retinopatía Diabética/metabolismo , Femenino , Humanos , Resistencia a la Insulina , Degeneración Macular/metabolismo , Masculino , Estudios Prospectivos , Adulto JovenRESUMEN
To create expected differences in oxidation ground beef samples from grass-fed and grain-fed animals were utilized in six differing percentages with 4 different packaging types. Percentages of grass-fed and grain-fed ground beef (GB) consisted of 100% grain fed GB; 80% grain-fed: 20% grass-fed GB; 60% grain-fed: 40% grass-fed GB; 40% grain-fed: 60% grass-fed GB; 20% grain-fed: 80% grass-fed GB; and 100% grass-fed GB. Packaging treatments included: high oxygen (HO; 80% O2: 20% CO2), low oxygen (LO; 65% N2: 35% CO2), carbon monoxide (CO; 65% N2: 34.6% CO2: 0.4% CO), and overwrap (OV; polyvinyl chloride film wrapped over a styrofoam tray). The modified TBARS method showed greater sensitivity and increased differences between treatments with less variability. The original extraction method showed fewer differences between treatments with greater variability. Data suggest that the modified method of TBARS determination could provide researchers with a better assay to find differences while decreasing the amount of labor.
Asunto(s)
Carne Roja/análisis , Sustancias Reactivas al Ácido Tiobarbitúrico/química , Alimentación Animal/análisis , Animales , Bovinos , Embalaje de Alimentos , Oxígeno , Poaceae/química , Poaceae/clasificación , Sensibilidad y EspecificidadRESUMEN
Three Dimensional Printing is a novel technique used in the fabrication of complex oral dosage delivery pharmaceuticals. It is possible to engineer devices with complicated internal geometries, varying densities and diffusivities, and multiple actives and excipients. Samples were fabricated using this technique using standard pharmaceutical materials. Erosion mechanism delayed-release tablets were constructed with varying polymer content from 8.9 to 17. 9%. Lag times varied between 25 and 50 min with a corresponding decrease in release rate as polymer content increased. Diffusion mechanism tablets were constructed with varying polymer content from 9.0 to 16.7%. The peak release rate decreased and the time to exhaustion increased with polymer content, whereas lag time was not affected. Active delivery studies with fluorescein indicated that Three Dimensional Printing is capable of accurately constructing dosage forms with active content as low as 10(-12) moles per tablet. Hardness and friability testing indicated that samples fabricated with this technique are comparable to other standard pharmaceutical products.
Asunto(s)
Preparaciones de Acción Retardada , Composición de Medicamentos/métodos , Algoritmos , Celulosa , Industria Farmacéutica/instrumentación , Excipientes , Fluoresceína/química , Dureza , Cinética , Proyectos Piloto , Polvos , Solubilidad , Espectrometría de Fluorescencia , Comprimidos RecubiertosRESUMEN
Four types of complex oral drug delivery devices have been fabricated using the three dimensional printing process. Immediate-extended release tablets were fabricated which were composed of two drug-containing sections of different pH-based release mechanisms. Pulsed release of chlorpheniramine maleate occurred after a lag time of 10 min followed by extended release of the compound over a period of 7 h. Breakaway tablets were fabricated composed of three sections. An interior fast-eroding section separating two drug-releasing sub-units eroded in 30-45 min in simulated gastric fluid. Enteric dual pulsatory tablets were constructed of one continuous enteric excipient phase into which diclofenac sodium was printed into two separated areas. These samples showed two pulses of release during in vitro USP dissolution at 1 and 8 h with a lag time between pulses of about 4 h. Dual pulsatory tablets were also fabricated. These samples were composed of two erosion based excipient sections of opposite pH based solubility. One section eroded immediately during the acid dissolution stage releasing diclofenac during the first 30 min, and the second section began eroding 5 h later during the high pH stage.
Asunto(s)
Preparaciones de Acción Retardada , Composición de Medicamentos/métodos , Formas de Dosificación , Composición de Medicamentos/instrumentación , Excipientes , Concentración de Iones de Hidrógeno , Polvos , Solubilidad , Comprimidos RecubiertosRESUMEN
USDA Select striploins (IMPS 180; n= 24) were cut into thirds (anterior, medial, and posterior) and assigned to 1 of 8 treatments utilizing a randomized incomplete block design. Treatments included (1) control (C); (2) 1.5% conjugated linoleic acid (conjugated linoleic acid = CLA) (CGA); (3) 0.4% sodium tripolyphosphate (PHO); (4) 0.5% salt (SAL); (5) 0.4% sodium tripolyphosphate, 0.5% salt (SPH); (6) 0.4% sodium tripolyphosphate, 1.5% CLA (PCL); (7) 0.5% salt, 1.5% CLA (SCL); and (8) 0.4% sodium tripolyphosphate, 0.5% salt, 1.5% CLA (SPC). Treatments were injected with solutions to 110% (10% pump) of their original weight. Treatments with CLA had higher (P < 0.05) marbling scores than treatments that did not. Not including SAL, treatments with salt, or phosphate or a combination of the two had higher tenderness values when sampled by panelists. Fresh steaks with inclusion of CLA had greater amounts (P < 0.05) of the CLA isomers than steaks not having CLA. Cooked steaks having CLA also had greater amounts (P < 0.05) of CLA, except for SCL, which were not different (P > 0.05) from the non-CLA treatments. Day was a significant source of variability for a*, b*, and saturation index. Treatment x day interactions were significant (P < 0.05) for hue angle and L* values. These data suggest that inclusion of CLA can increase amounts of CLA isomers without major deleterious effects to instrumental, physical, and quality characteristics of beef striploin steaks.
Asunto(s)
Conservación de Alimentos/métodos , Ácidos Linoleicos Conjugados/farmacología , Carne/normas , Pigmentación/efectos de los fármacos , Polifosfatos/farmacología , Cloruro de Sodio/farmacología , Animales , Bovinos , Estudios Cruzados , Sinergismo Farmacológico , Conservantes de Alimentos/farmacología , Humanos , Sustancias Reactivas al Ácido Tiobarbitúrico/análisisRESUMEN
USDA Select striploins (n = 20) were cut into thirds (anterior, medial, and posterior) and randomly assigned to 1 of 6 treatments. Treatments included: (1) control (C); (2) 0.006% BHA (butylated hydroxyl anisole)/BHT (butylated hydroxytoluene) (70%/30%) (BB); (3) 0.4% trisodiumphosphate (CT); (4) 0.4% sodiumtripolyphosphate with 0.5% salt (BH); (5) sodiumtripolyphosphate, 0.5% salt, and 0.006% BHA/BHT (70%/30%) (SB); (6) 0.2% sodiumtripolyphosphate, 0.2% trisodiumphosphate, and 0.5% salt (STB). Muscle sections were injected to 110% (10% pump) of their weight with their respective treatments. Inclusion of BHA/BHT allowed for lower mean oxidation values. Regardless of phosphate type, muscles treated with both phosphate and salt had lower retail purge (P < 0.05). Sensory panelists rated (P < 0.05) STB, SB, and BH to be juicier than all other treatments. These data suggest that inclusion of both salt and phosphate can enhance palatability, lower cook loss, and retail purge.