Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 781
Filtrar
1.
Glob Chang Biol ; 30(8): e17436, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39162201

RESUMEN

Measurements of net primary productivity (NPP) and litter decomposition from tropical peatlands are severely lacking, limiting our ability to parameterise and validate models of tropical peatland development and thereby make robust predictions of how these systems will respond to future environmental and climatic change. Here, we present total NPP (i.e., above- and below-ground) and decomposition data from two floristically and structurally distinct forested peatland sites within the Pastaza Marañón Foreland Basin, northern Peru, the largest tropical peatland area in Amazonia: (1) a palm (largely Mauritia flexuosa) dominated swamp forest and (2) a hardwood dominated swamp forest (known as 'pole forest', due to the abundance of thin-stemmed trees). Total NPP in the palm forest and hardwood-dominated forest (9.83 ± 1.43 and 7.34 ± 0.84 Mg C ha-1 year-1, respectively) was low compared with values reported for terra firme forest in the region (14.21-15.01 Mg C ha-1 year-1) and for tropical peatlands elsewhere (11.06 and 13.20 Mg C ha-1 year-1). Despite the similar total NPP of the two forest types, there were considerable differences in the distribution of NPP. Fine root NPP was seven times higher in the palm forest (4.56 ± 1.05 Mg C ha-1 year-1) than in the hardwood forest (0.61 ± 0.22 Mg C ha-1 year-1). Above-ground palm NPP, a frequently overlooked component, made large contributions to total NPP in the palm-dominated forest, accounting for 41% (14% in the hardwood-dominated forest). Conversely, Mauritia flexuosa litter decomposition rates were the same in both plots: highest for leaf material, followed by root and then stem material (21%, 77% and 86% of mass remaining after 1 year respectively for both plots). Our results suggest potential differences in these two peatland types' responses to climate and other environmental changes and will assist in future modelling studies of these systems.


Mediciones de la productividad primaria neta (PPN) y la descomposición de materia orgánica de las turberas tropicales son escasas, lo que limita nuestra capacidad para parametrizar y validar modelos de desarrollo de las turberas tropicales y, en consecuencia, realizar predicciones sólidas sobre la respuesta de estos sistemas ante futuros cambios ambientales y climáticos. En este estudio, presentamos datos de PPN total (es decir, biomasa aérea y subterránea) y descomposición de la materia orgánica colectada en dos turberas boscosas con características florísticas y estructurales contrastantes dentro de la cuenca Pastaza Marañón al norte del Perú, el área de turberas tropicales más grande de la Amazonia: (1) un bosque pantanoso dominado por palmeras (principalmente Mauritia flexuosa) y (2) un bosque pantanosos dominado por árboles leñosos de tallo delgado (conocido como 'varillal hidromórfico'). La PPN total en el bosque de palmeras y el varillal hidromórfico (9,83 ± 1,43 y 7,34 ± 0,84 Mg C ha­1 año­1 respectivamente) fue baja en comparación con los valores reportados para los bosques de tierra firme en la región (14,21­15,01 Mg C ha­1 año­1) y para turberas tropicales en otros lugares (11,06 y 13,20 Mg C ha­1 año­1). A pesar de que la PPN total fue similar en ambos tipos de bosque, hubo diferencias considerables en la distribución de la PPN. La PPN de las raíces finas fue siete veces mayor en el bosque de palmeras (4,56 ± 1,05 Mg C ha­1 año­1) que en el varillal hidromórfico (0,61 ± 0,22 Mg C ha­1 año­1). La PPN de la biomasa aérea de las palmeras, un componente ignorado frecuentemente, contribuyó en gran medida a la PPN total del bosque de palmeras, representando el 41% (14% en el varillal hidromórfico). Por el contrario, la tasa de descomposición de materia orgánica de Mauritia flexuosa fue la misma en ambos sitios: la más alta corresponde a la hojarasca, seguida por las raíces y luego el tallo (21%, 77% y 86% de la masa restante después de un año, respectivamente para ambos sitios). Nuestros resultados sugieren diferencias potenciales en la respuesta de estos dos tipos de turberas al clima y otros cambios ambientales, y ayudarán en futuros estudios de modelamiento de estos sistemas.


Asunto(s)
Bosques , Perú , Humedales , Suelo/química , Hojas de la Planta/metabolismo , Clima Tropical
2.
Phys Rev Lett ; 130(18): 183602, 2023 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-37204878

RESUMEN

The Heisenberg limit to laser coherence C-the number of photons in the maximally populated mode of the laser beam-is the fourth power of the number of excitations inside the laser. We generalize the previous proof of this upper bound scaling by dropping the requirement that the beam photon statistics be Poissonian (i.e., Mandel's Q=0). We then show that the relation between C and sub-Poissonianity (Q<0) is win-win, not a tradeoff. For both regular (non-Markovian) pumping with semiunitary gain (which allows Q→-1), and random (Markovian) pumping with optimized gain, C is maximized when Q is minimized.

3.
Postgrad Med ; 135(3): 214-223, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35275765

RESUMEN

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disease, symmetrically affecting the small joints. Biomarkers are tools that can be used in the diagnosis and monitoring of RA. AIM: To systematically explore the role of the biomarkers: C-reactive protein (CRP), rheumatoid factor (RF), anti-cyclic citrullinated protein (Anti-CCP), 14-3-3η protein, and the multi-biomarker disease activity (MBDA) score for the diagnosis and treatment of RA. METHODS: A systematic review of the English literature using four different databases was carried out. RESULTS: CRP >7.1 mg/L predicted poor conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) outcome in RA. Anti-CCP, CRP ≥0.3 mg/dL, and RF predicted bone erosion and cartilage destruction. Combination of high 14-3-3η protein with RF and CRP improved the prediction of rapid erosion progression (REP). Anti-CCP was not associated with disease activity but was associated with increased radiographic damage (r = 0.46, p = 0.048). RF was not associated with joint damage but correlated with ultrasound-detected bone erosion. The 14-3-3η protein significantly correlated with inflammation, bone rremodeling, and osteoporosis in RA patients (p < 0.05). In addition, the 14-3-3η protein positively correlated with RA duration (p = 0.003), disease aactivity, and positive RF (p = 0.025) and it distinguished early from established RA. Early MBDA scores correlated with later response in disease activity after 6 and 12 weeks of treatment (p < 0.05). The MBDA score was able to differentiate between small differences in disease activity, predicted remission over 1-year pperiod, and was a strong predictor of radiographic progression of RA. CONCLUSION: The investigated biomarkers are helpful tools in clinical practice for diagnosis, monitoring of treatment, and predicting prognosis in RA patients. However, further research is still required to investigate novel biomarkers for the pre-treatment selection of potentially responsive patients before starting therapy for a precision medicine in this area.


Asunto(s)
Proteínas 14-3-3 , Artritis Reumatoide , Humanos , Proteínas 14-3-3/metabolismo , Artritis Reumatoide/diagnóstico , Artritis Reumatoide/tratamiento farmacológico , Biomarcadores , Pronóstico , Proteína C-Reactiva/metabolismo
4.
Anaesthesia ; 77 Suppl 1: 43-48, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35001384

RESUMEN

Traumatic brain injury is the alteration in brain function due to an external force. It is common and affects millions of people worldwide annually. The World Health Organization estimates that 90% of global deaths caused by injuries occur in low- and middle-income countries, with traumatic brain injury contributing up to half of these trauma-related deaths. Patients with traumatic brain injury in low- and middle-income countries have twice the odds of dying compared with their counterparts in high-income countries. Sedation is a key element of care in the management of traumatic brain injury, used for its neuroprotective effects and to prevent secondary brain injury. While sedatives have the potential to improve outcomes, they can be challenging to administer and have potentially dangerous complications. Sedation in low-resource settings should aim to be effective, safe, affordable and feasible. In this paper, we summarise the indications for sedation in traumatic brain injury, the choice of sedative drugs and the pragmatic management and monitoring of sedated traumatic brain injury patients in low-resource settings.


Asunto(s)
Anestesia/economía , Lesiones Traumáticas del Encéfalo/economía , Lesiones Traumáticas del Encéfalo/prevención & control , Recursos en Salud/economía , Hipnóticos y Sedantes/economía , Pobreza/economía , Anestesia/métodos , Anestesia/normas , Toma de Decisiones Clínicas/métodos , Recursos en Salud/normas , Humanos , Hipnóticos y Sedantes/administración & dosificación , Hipnóticos y Sedantes/normas
5.
Clin Rheumatol ; 40(10): 4061-4070, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33934270

RESUMEN

OBJECTIVES: To compare healthcare resource utilization and costs among patients with psoriasis, psoriatic arthritis (PsA), and a control group of patients without psoriasis and PsA in the USA. METHODS: The IBM® MarketScan® Commercial Database was used to identify three adult patient groups from 1/1/2009 through 4/30/2020: (1) Psoriasis: ≥ 2 diagnoses ≥ 30 days apart for psoriasis (no PsA diagnoses); (2) PsA: ≥ 2 diagnoses for PsA; (3) Control: no psoriasis or PsA diagnoses in their entire claims records. Patients with comorbid rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, or ulcerative colitis were excluded from the analyses. Controls were matched 1:1 to psoriasis and PsA patients based on age, gender, index year, and number of non-rheumatological comorbidities. Healthcare resource utilization and costs (in 2019 USD) were evaluated descriptively and through mixed models for five years of follow-up. RESULTS: A total of 142,531 psoriasis and 21,428 PsA patients were matched to the control group (N = 163,959). Annual all-cause healthcare costs per patient were $7,470, $11,062, and $29,742 for the control, psoriasis, and PsA groups, respectively. All-cause healthcare costs increased over time and were significantly greater among PsA vs. psoriasis (p < 0.0001) and the control groups (p < 0.0001). Across all categories of healthcare resources, utilization was greatest among patients with PsA and lowest in the control group. CONCLUSION: Annual healthcare costs and resource utilization were significantly higher with PsA compared with psoriasis and the control group, confirming the substantial economic burden of PsA. The cost disparity between these patient groups highlights a continued unmet medical need. Key Points • Patients with PsA incurred significantly greater healthcare resource utilization and costs than patients with psoriasis and patients without psoriasis and PsA. • Significantly greater costs and healthcare resource utilization were also observed among patients with psoriasis compared with patients without psoriasis and PsA.


Asunto(s)
Artritis Psoriásica , Psoriasis , Adulto , Artritis Psoriásica/terapia , Costos de la Atención en Salud , Humanos , Aceptación de la Atención de Salud , Psoriasis/terapia , Estudios Retrospectivos , Estados Unidos
6.
Trop Doct ; 51(3): 387-390, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33461407

RESUMEN

Myasthenia gravis is a rare autoimmune disease, which presents with ocular or generalised symptoms. Few publications describe its prevalence in African populations. We describe a young woman who was diagnosed with myasthenia gravis in a Malawian public hospital and outline the challenges encountered in managing this condition in a low-resource setting.


Asunto(s)
Miastenia Gravis , Femenino , Humanos , Miastenia Gravis/diagnóstico , Miastenia Gravis/terapia , Prevalencia , Síndrome de Dificultad Respiratoria , Adulto Joven
7.
Public Health Nutr ; 24(8): 2313-2317, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33198839

RESUMEN

We have recently been funded by the UK Prevention Research Partnership (UKPRP) to develop a UK school food network. The overarching aim is to build a community working towards a more health-promoting food and nutrition system in UK schools (primary and secondary). Here we describe the current status of school food research, including a review of the literature supporting the health-promoting schools approach and outline the opportunities for intervention and innovation establishment of the network present. Key potential school food research themes are described, and their prioritisation within the network, as well as network activities that have been planned, with the ultimate ambition of reducing socio-economic diet-related inequalities, and, consequently, non-communicable disease risk.


Asunto(s)
Servicios de Alimentación , Instituciones Académicas , Alimentos , Humanos , Estado Nutricional , Reino Unido
8.
Traffic Inj Prev ; 21(5): 313-318, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32319815

RESUMEN

Objective: There is little research simultaneously examining both teen drivers' characteristics and the driving environment. This study aimed to investigate how traffic engineering factors (road designs, traffic operations, and surface conditions) contribute to risks of teen driver's fatality. Understanding the role of traffic engineering factors can further improve efforts to reduce teen diving-related fatal crashes.Methods: This study used the Fatality Analysis Reporting System and General Estimate System for years 2014 to 2015. We explored numerous engineering variables: horizontal/vertical alignment, intersections types, interchange areas, traffic ways types, posted speed limit, work zone areas, types of traffic control devices and road surface conditions. Traditional variables considered in this study included sex, age, presence of passengers in relation to age group, time of day, lighting condition, season, vehicle model year, vehicle type, seatbelt use, crash type and movement prior to a crash. We ran cross-tabulations and unadjusted analyses to report unadjusted odds ratios of teen driver's fatality. A multiple logistic regression model was used to identify which variables related to road design and traffic operations remained significant after being adjusted by other variables.Results: For traditional factors, results corroborated prior findings. All the engineering factors, except work zone area, were significant in the unadjusted analyses; four variables - horizontal alignments, posted speed limit, traffic control device type, and traffic way type - remained statistically significant in the final model. The adjusted odds ratio (AOR) of curved high-speed segment was nearly seven times (6.94; 95% CI = 3.58, 13.46) that of a straight segment with a low posted speed limit (reference group). The AOR of no traffic control was four times (4.17; 95% CI = 2.95, 5.88) that of roads with traffic controls. The AOR of a two-way undivided road was almost three times (2.75, 95% CI = 1.43, 5.29) that of a two-way median barrier road (reference group).Conclusions: This study suggests teen driver education programs consider addressing road design characteristics. For example, incorporating focused lessons on traffic signs and traffic control types may better prepare young people for their driving experiences. Additionally, more supervised driving time is needed on various road types, especially those that present greater risks (e.g., roads with grades/curves, intersections with no traffic signal, undivided roads, and unpaved roads).


Asunto(s)
Accidentes de Tránsito/mortalidad , Conducción de Automóvil/estadística & datos numéricos , Planificación Ambiental/estadística & datos numéricos , Transportes , Accidentes de Tránsito/estadística & datos numéricos , Adolescente , Factores de Edad , Femenino , Humanos , Masculino , Factores Sexuales , Estados Unidos/epidemiología , Adulto Joven
9.
Sci Total Environ ; 642: 436-446, 2018 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-29906733

RESUMEN

Time series remote sensing vegetation indices derived from SPOT 5 data are compared with vegetation structure and eddy covariance flux data at 15 dry to wet reclamation and reference sites within the Oil Sands region of Alberta, Canada. This comprehensive analysis examines the linkages between indicators of ecosystem function and change trajectories observed both at the plot level and within pixels. Using SPOT imagery, we find that higher spatial resolution datasets (e.g. 10 m) improves the relationship between vegetation indices and structural measurements compared with interpolated (lower resolution) pixels. The simple ratio (SR) vegetation index performs best when compared with stem density-based indicators (R2 = 0.65; p < 0.00), while the normalised difference vegetation index (NDVI) and soil adjusted vegetation index (SAVI) are most comparable to foliage indicators (leaf area index (LAI) and canopy cover (R2 = 0.52-0.78; p > 0.02). Fluxes (net ecosystem production (NEP) and gross ecosystem production (GEP)) are most related to NDVI and SAVI when these are interpolated to larger 20 m × 20 m pixels (R2 = 0.44-0.50; p < 0.00). As expected, decreased sensitivity of NDVI is problematic for sites with LAI > 3 m2 m-2, making this index more appropriate for newly regenerating reclamation areas. For sites with LAI < 3 m2 m-2, trajectories of vegetation change can be mapped over time and are within 2.7% and 3.3% of annual measured LAI changes observed at most sites. This study demonstrates the utility of remote sensing in combination with field and eddy covariance data for monitoring and scaling of reclaimed and reference site productivity within and beyond the Oil Sands Region of western Canada.

11.
Nat Commun ; 9(1): 12, 2018 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-29295991

RESUMEN

Here we test the hypothesis that the neurodegenerative process in Parkinson's disease (PD) moves stereotypically along neural networks, possibly reflecting the spread of toxic alpha-synuclein molecules. PD patients (n = 105) and matched controls (n = 57) underwent T1-MRI at entry and 1 year later as part of the Parkinson's Progression Markers Initiative. Over this period, PD patients demonstrate significantly greater cortical thinning than controls in parts of the left occipital and bilateral frontal lobes and right somatomotor-sensory cortex. Cortical thinning is correlated to connectivity (measured functionally or structurally) to a "disease reservoir" evaluated by MRI at baseline. The atrophy pattern in the ventral frontal lobes resembles one described in certain cases of Alzheimer's disease. Our findings suggest that disease propagation to the cortex in PD follows neuronal connectivity and that disease spread to the cortex may herald the onset of cognitive impairment.


Asunto(s)
Corteza Cerebral/patología , Conectoma , Enfermedad de Parkinson/patología , Anciano , Estudios de Casos y Controles , Cognición , Progresión de la Enfermedad , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/líquido cefalorraquídeo , Enfermedad de Parkinson/etiología , Enfermedad de Parkinson/psicología
12.
Pharmacogenomics J ; 18(1): 136-143, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28290528

RESUMEN

A common haplotype of the flavin-containing monooxygenase gene FMO3 is associated with aberrant mRNA splicing, a twofold reduction in in vivo nicotine N-oxidation and reduced nicotine dependence. Tobacco remains the largest cause of preventable mortality worldwide. CYP2A6, the primary hepatic nicotine metabolism gene, is robustly associated with cigarette consumption but other enzymes contribute to nicotine metabolism. We determined the effects of common variants in FMO3 on plasma levels of nicotine-N-oxide in 170 European Americans administered deuterated nicotine. The polymorphism rs2266780 (E308G) was associated with N-oxidation of both orally administered and ad libitum smoked nicotine (P⩽3.3 × 10-5 controlling for CYP2A6 genotype). In vitro, the FMO3 G308 variant was not associated with reduced activity, but rs2266780 was strongly associated with aberrant FMO3 mRNA splicing in both liver and brain (P⩽6.5 × 10-9). Surprisingly, in treatment-seeking European American smokers (n=1558) this allele was associated with reduced nicotine dependence, specifically with a longer time to first cigarette (P=9.0 × 10-4), but not with reduced cigarette consumption. As N-oxidation accounts for only a small percentage of hepatic nicotine metabolism we hypothesized that FMO3 genotype affects nicotine metabolism in the brain (unlike CYP2A6, FMO3 is expressed in human brain) or that nicotine-N-oxide itself has pharmacological activity. We demonstrate for the first time nicotine N-oxidation in human brain, mediated by FMO3 and FMO1, and show that nicotine-N-oxide modulates human α4ß2 nicotinic receptor activity in vitro. These results indicate possible mechanisms for associations between FMO3 genotype and smoking behaviors, and suggest nicotine N-oxidation as a novel target to enhance smoking cessation.


Asunto(s)
Encéfalo/metabolismo , Nicotina/efectos adversos , Nicotina/metabolismo , Oxigenasas/genética , Oxigenasas/metabolismo , Polimorfismo Genético/genética , Tabaquismo/genética , Alelos , Animales , Células Cultivadas , Genotipo , Haplotipos/genética , Humanos , Masculino , Persona de Mediana Edad , Oocitos/metabolismo , Oxidación-Reducción , Fumar/genética , Fumar/metabolismo , Tabaquismo/metabolismo , Población Blanca , Xenopus/genética
13.
Mol Psychiatry ; 23(9): 1911-1919, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-28972577

RESUMEN

Cigarette smoking is a leading cause of preventable mortality worldwide. Nicotine dependence, which reduces the likelihood of quitting smoking, is a heritable trait with firmly established associations with sequence variants in nicotine acetylcholine receptor genes and at other loci. To search for additional loci, we conducted a genome-wide association study (GWAS) meta-analysis of nicotine dependence, totaling 38,602 smokers (28,677 Europeans/European Americans and 9925 African Americans) across 15 studies. In this largest-ever GWAS meta-analysis for nicotine dependence and the largest-ever cross-ancestry GWAS meta-analysis for any smoking phenotype, we reconfirmed the well-known CHRNA5-CHRNA3-CHRNB4 genes and further yielded a novel association in the DNA methyltransferase gene DNMT3B. The intronic DNMT3B rs910083-C allele (frequency=44-77%) was associated with increased risk of nicotine dependence at P=3.7 × 10-8 (odds ratio (OR)=1.06 and 95% confidence interval (CI)=1.04-1.07 for severe vs mild dependence). The association was independently confirmed in the UK Biobank (N=48,931) using heavy vs never smoking as a proxy phenotype (P=3.6 × 10-4, OR=1.05, and 95% CI=1.02-1.08). Rs910083-C is also associated with increased risk of squamous cell lung carcinoma in the International Lung Cancer Consortium (N=60,586, meta-analysis P=0.0095, OR=1.05, and 95% CI=1.01-1.09). Moreover, rs910083-C was implicated as a cis-methylation quantitative trait locus (QTL) variant associated with higher DNMT3B methylation in fetal brain (N=166, P=2.3 × 10-26) and a cis-expression QTL variant associated with higher DNMT3B expression in adult cerebellum from the Genotype-Tissue Expression project (N=103, P=3.0 × 10-6) and the independent Brain eQTL Almanac (N=134, P=0.028). This novel DNMT3B cis-acting QTL variant highlights the importance of genetically influenced regulation in brain on the risks of nicotine dependence, heavy smoking and consequent lung cancer.


Asunto(s)
ADN (Citosina-5-)-Metiltransferasas/genética , Tabaquismo/genética , Adulto , Negro o Afroamericano/genética , Anciano , Alelos , Población Negra/genética , ADN (Citosina-5-)-Metiltransferasas/fisiología , Femenino , Frecuencia de los Genes/genética , Predisposición Genética a la Enfermedad/genética , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple/genética , Sitios de Carácter Cuantitativo/genética , Fumar/genética , Población Blanca/genética , ADN Metiltransferasa 3B
14.
Clin Pharmacol Ther ; 101(6): 736-744, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28510297

RESUMEN

This report serves as a summary of a 2-day public workshop sponsored by the US Food and Drug Administration (FDA) to discuss the safety of drugs and biological products used during lactation. The aim of the workshop was to provide a forum to discuss the collection of data to inform the potential risks to breastfed infants with maternal use of medications during lactation. Discussions included the review of current approaches to collect data on medications used during lactation, and the considerations for future approaches to design and guide clinical lactation studies. This workshop is part of continuing efforts to raise the awareness of the public for women who choose to breastfeed their infants.


Asunto(s)
Productos Biológicos/efectos adversos , Lactancia Materna/efectos adversos , Conferencias de Consenso como Asunto , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/etiología , Lactancia , Exposición Materna/efectos adversos , Congresos como Asunto , Femenino , Humanos , Lactante , Recién Nacido , Modelos Biológicos , Embarazo , Medición de Riesgo , Factores de Riesgo
15.
Conserv Biol ; 31(6): 1283-1292, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28272753

RESUMEN

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza-Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land-use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon-dense (domed pole forest) areas. New carbon-based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.


Asunto(s)
Conservación de los Recursos Naturales , Humedales , Indonesia , Malasia , Perú
16.
Exp Neurol ; 287(Pt 2): 225-234, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27456270

RESUMEN

For most individuals, the respiratory control system produces a remarkably stable and coordinated motor output-recognizable as a breath-from birth until death. Very little is understood regarding the processes by which the respiratory control system maintains network stability in the presence of changing physiological demands and network properties that occur throughout life. An emerging principle of neuroscience is that neural activity is sensed and adjusted locally to assure that neurons continue to operate in an optimal range, yet to date, it is unknown whether such homeostatic plasticity is a feature of the neurons controlling breathing. Here, we review the evidence that local mechanisms sense and respond to perturbations in respiratory neural activity, with a focus on plasticity in respiratory motor neurons. We discuss whether these forms of plasticity represent homeostatic plasticity in respiratory control. We present new analyses demonstrating that reductions in synaptic inputs to phrenic motor neurons elicit a compensatory enhancement of phrenic inspiratory motor output, a form of plasticity termed inactivity-induced phrenic motor facilitation (iPMF), that is proportional to the magnitude of activity deprivation. Although the physiological role of iPMF is not understood, we hypothesize that it has an important role in protecting the drive to breathe during conditions of prolonged or intermittent reductions in respiratory neural activity, such as following spinal cord injury or during central sleep apnea.


Asunto(s)
Homeostasis/fisiología , Neuronas Motoras/fisiología , Plasticidad Neuronal/fisiología , Respiración , Sinapsis/fisiología , Animales , Humanos , Nervio Frénico/fisiología
17.
Exp Neurol ; 287(Pt 2): 235-242, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27474512

RESUMEN

Two critical parameters that influence breathing stability are the levels of arterial pCO2 at which breathing ceases and subsequently resumes - termed the apneic and recruitment thresholds (AT and RT, respectively). Reduced respiratory neural activity elicits a chemoreflex-independent, long-lasting increase in phrenic burst amplitude, a form of plasticity known as inactivity-induced phrenic motor facilitation (iPMF). The physiological significance of iPMF is unknown. To determine if iPMF and neural apnea have long-lasting physiological effects on breathing, we tested the hypothesis that patterns of neural apnea that induce iPMF also elicit changes in the AT and RT. Phrenic nerve activity and end-tidal CO2 were recorded in urethane-anesthetized, ventilated rats to quantify phrenic nerve burst amplitude and the AT and RT before and after three patterns of neural apnea that differed in their duration and ability to elicit iPMF: brief intermittent neural apneas, a single brief "massed" neural apnea, or a prolonged neural apnea. Consistent with our hypothesis, we found that patterns of neural apnea that elicited iPMF also resulted in changes in the AT and RT. Specifically, intermittent neural apneas progressively decreased the AT with each subsequent neural apnea, which persisted for at least 60min. Similarly, a prolonged neural apnea elicited a long-lasting decrease in the AT. In both cases, the magnitude of the AT decrease was proportional to iPMF. In contrast, the RT was transiently decreased following prolonged neural apnea, and was not proportional to iPMF. No changes in the AT or RT were observed following a single brief neural apnea. Our results indicate that the AT and RT are differentially altered by neural apnea and suggest that specific patterns of neural apnea that elicit plasticity may stabilize breathing via a decrease in the AT.


Asunto(s)
Potenciales de Acción/fisiología , Apnea/fisiopatología , Dióxido de Carbono/metabolismo , Neuronas Motoras/fisiología , Nervio Frénico/fisiología , Umbral Sensorial/fisiología , Potenciales de Acción/efectos de los fármacos , Análisis de Varianza , Anestesia , Animales , Apnea/patología , Análisis de los Gases de la Sangre , Presión Sanguínea/efectos de los fármacos , Dióxido de Carbono/farmacología , Modelos Animales de Enfermedad , Masculino , Neuronas Motoras/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
18.
Phys Rev Lett ; 119(25): 251301, 2017 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-29303333

RESUMEN

The detection of an electromagnetic counterpart (GRB 170817A) to the gravitational-wave signal (GW170817) from the merger of two neutron stars opens a completely new arena for testing theories of gravity. We show that this measurement allows us to place stringent constraints on general scalar-tensor and vector-tensor theories, while allowing us to place an independent bound on the graviton mass in bimetric theories of gravity. These constraints severely reduce the viable range of cosmological models that have been proposed as alternatives to general relativistic cosmology.

19.
Autoimmune Dis ; 2017: 1872846, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29435367

RESUMEN

BACKGROUND: The subclinical pathophysiology of proliferative lupus nephritis (PLN) has not been fully elucidated. Myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) is associated with PLN, but prediagnostic levels have not been reported. METHODS: We performed a retrospective case-control Department of Defense Serum Repository (DoDSR) study comparing MPO-ANCA levels in longitudinal prediagnostic serum samples for 23 biopsy confirmed proliferative lupus nephritis (PLN) patients to DoDSR identified age, sex, race, and age of serum matched healthy and SLE without LN disease controls. We also compared the temporal relationship of MPO-ANCA to anti-double stranded DNA antibodies (dsDNAab). RESULTS: A greater proportion of PLN patients had prediagnostic MPO-ANCA levels above ≥3 U/mL and ≥6 U/mL compared to SLE without LN (91% versus 43%, p < 0.001; 57% versus 5%, p < 0.001, resp.). In subgroup analysis, the MPO-ANCA threshold of ≥3 U/mL was significant at <1 year (88% versus 39%, p = 0.007) and 1-4 years (87% versus 38%, p = 0.009) prior to diagnosis. Statistically significant subclinical MPO-ANCA levels (≥3 U/mL) occurred prior to statistically significant dsDNAab ≥ 3 IU/ml (89% versus 11%, p = 0.003). CONCLUSIONS: Subclinical MPO-ANCA levels could distinguish future PLN from SLE without LN. MPO-ANCA manifests prior to clinical disease and subclinical dsDNAab to suggest that it may contribute directly to PLN pathogenicity.

20.
J Chem Ecol ; 42(9): 896-907, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27744621

RESUMEN

High-emission-rate "mega-dispensers" have come into increasing use for sex pheromone mating disruption of moth pests over the past two decades. These commercially available dispensers successfully suppress mating and reduce crop damage when they are deployed at very low to moderate densities, ranging from 1 to 5/ha to 100-1000/ha, depending on the dispenser types and their corresponding pheromone emission rates. Whereas traditionally the emission rates for successful commercial mating disruption formulations have been measured in terms of amounts (usually milligram) emitted by the disruptant application per acre or hectare per day, we suggest that emission rates should be measured on a per-dispenser per-minute basis. In addition we suggest, because of our knowledge concerning upwind flight of male moths being dependent on contact with pheromone plume strands, that more attention needs to be paid to optimizing the flux within plume strands that shear off of any mating disruption dispenser's surface. By measuring the emission rates on a per-minute basis and measuring the plume strand concentrations emanating from the dispensers, it may help improve the ability of the dispensers to initiate upwind flight from males and initiate their habituation to the pheromone farther downwind than can otherwise be achieved. In addition, by optimizing plume strand flux by paying attention to the geometries and compactness of mating disruption mega-dispensers may help reduce the cost of mega-dispenser disruption formulations by improving their behavioral efficacy while maintaining field longevity and using lower loading rates per dispenser.


Asunto(s)
Control de Insectos/instrumentación , Mariposas Nocturnas/fisiología , Atractivos Sexuales/metabolismo , Animales , Productos Agrícolas/parasitología , Diseño de Equipo , Femenino , Control de Insectos/métodos , Masculino , Reproducción , Atractivos Sexuales/análisis , Conducta Sexual Animal , Zea mays/parasitología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA