Fire regimes during the last glacial

Sedimentary charcoal records document changes in fire regime. We have identified 67 sites (30 sites with better than millennial resolution) which have records for some part of the Last Glacial to analyse changes in global fire regimes. Fire was consistently lower during the glacial than during the Eemian and Holocene. Within the glacial, Marine Isotope Stage (MIS) 3 is characterised globally by more fire than MIS 2. The signal for MIS 4 is less clear: there is more fire in the Northern Hemisphere and less fire in the Southern Hemisphere than during MIS 2 and 3. The records, most particularly records from the northern extratropics, show millennial-scale variability in fire regimes corresponding to the rapid climate changes associated with Dansgaard–Oeschger (D-O) cycles. Most of the D-O cycles during the Last Glacial and all of the Heinrich stadials are apparent in the composite global record of fire regime: fire increases during D-O warming events and decreases during intervals of rapid cooling. Our analyses show that fire regimes show a lagged response to rapid climate changes of ca 100–200 years in the case of D-O warming events, ca 0–100 years in the case of D-O cooling events and ca 200 years in the case of Heinrich Stadials. The Strong climatic variability experienced during the glacial resulted in important changes in fire regimes even though the base level of biomass burning was less than today.

Fire in the Earth System

Fire is an important component of the Earth System that is tightly coupled with climate, vegetation, biogeochemical cycles, and human activities. Observations of how fire regimes change on seasonal to millennial timescales are providing an improved understanding of the hierarchy of controls on fire regimes. Climate is the principal control on fire regimes, although human activities have had an increasing influence on the distribution and incidence of fire in recent centuries. Understanding of the controls and variability of fire also underpins the development of models, both conceptual and numerical, that allow us to predict how future climate and land-use changes might influence fire regimes. Although fires in fire-adapted ecosystems can be important for biodiversity and ecosystem function, positive effects are being increasingly outweighed by losses of ecosystem services. As humans encroach further into the natural habitat of fire, social and economic costs are also escalating. The prospect of near-term rapid and large climate changes, and the escalating costs of large wildfires, necessitates a radical re-thinking and the development of approaches to fire management that promote the more harmonious co-existence of fire and people.

Flavonoid-rich fruits and vegetables improve microvascular reactivity and inflammatory status in men at risk of cardiovascular disease – FLAVURS: a randomized controlled trial

BACKGROUND: Observed associations between increased fruit and vegetable (F&V) consumption, particularly those F&Vs that are rich in flavonoids, and vascular health improvements require confirmation in adequately powered randomized controlled trials. OBJECTIVE: This study was designed to measure the dose-response relation between high-flavonoid (HF), low-flavonoid (LF), and habitual F&V intakes and vascular function and other cardiovascular disease (CVD) risk indicators. DESIGN: A single-blind, dose-dependent, parallel randomized controlled dietary intervention study was conducted. Male and female low-F&V consumers who had a ≥1.5-fold increased risk of CVD (n = 174) were randomly assigned to receive an HF F&V, an LF F&V, or a habitual diet, with HF and LF F&V amounts sequentially increasing by 2, 4, and 6 (+2, +4, and +6) portions/d every 6 wk over habitual intakes. Microvascular reactivity (laser Doppler imaging with iontophoresis), arterial stiffness [pulse wave velocity, pulse wave analysis (PWA)], 24-h ambulatory blood pressure, and biomarkers of nitric oxide (NO), vascular function, and inflammation were determined at baseline and at 6, 12, and 18 wk. RESULTS: In men, the HF F&V diet increased endothelium-dependent microvascular reactivity (P = 0.017) with +2 portions/d (at 6 wk) and reduced C-reactive protein (P = 0.001), E-selectin (P = 0.0005), and vascular cell adhesion molecule (P = 0.0468) with +4 portions/d (at 12 wk). HF F&Vs increased plasma NO (P = 0.0243) with +4 portions/d (at 12 wk) in the group as a whole. An increase in F&Vs, regardless of flavonoid content in the groups as a whole, mitigated increases in vascular stiffness measured by PWA (P = 0.0065) and reductions in NO (P = 0.0299) in the control group. CONCLUSION: These data support recommendations to increase F&V intake to ≥6 portions daily, with additional benefit from F&Vs that are rich in flavonoids, particularly in men with an increased risk of CVD. This trial was registered at www.controlled-trials.com as ISRCTN47748735.

Auditory distraction in memory tasks: Can it be controlled?

Irrelevant sound accompanying the processes of encoding and retrieval of verbal events impairs memory performance. However, the degree of impairment is highly dependent on a range of factors. Some of them lie outside rememberers’ control, like the semantic content of distracting sound or the nature of a test used to assess memory. Others, like a strategy used to encode memoranda, rest under control of the rememberer. In this paper the factors that modulate memory impairment are outlined and discussed in terms of multiple mechanisms contributing to memory impairment under auditory distraction. The mechanisms of a capture of attention by distraction, interference of automatic seriation of distraction and voluntary seriation of memoranda, semantic inhibition of distraction, and blocking of memoranda by semantically related distracters are described. Results that demonstrate how these mechanisms determine memory impairment under auditory distraction are also discussed. Particular attention is devoted to the possibility of voluntary control over the workings of these mechanisms and the conditions under which the negative impact of auditory distraction upon memory performance could be minimised.

Postglacial vegetation, fire and climate dynamics at Central Chilean Patagonia (Lake Shaman, 44ºS)

A 19 cal ka BP pollen and charcoal record from Lake Shaman (44°S; 71°W, Chile) was analyzed to establish vegetation, fire and climate dynamics of the forest-steppe ecotone in Central Chilean Patagonia. Lake Shaman record indicates that the upper Río Cisnes valley was free of ice at around 19 cal ka BP. From this date and until 14.8 cal ka BP, a grass steppe with high proportions of shrubs associated to colder and drier conditions than present developed in this area. A continuous increase of Nothofagus accompanied by a decline in the steppe shrubs and sudden dominance of paludal over aquatic plants from 11 cal ka BP was associated to effective moisture increase but still under modern values. The replacement of the cold-dry grass-shrub steppe by a similar-than-present forest-steppe ecotone suggests an increase in temperature indicating the onset of the Holocene. At the same time, moderate fire activity suggested by the charcoal record could be related to major fuel availability as consequence of Nothofagus forest expansion. Between 8 and 3 cal ka BP, the record indicates the easternmost position of the forest-steppe ecotone suggesting the highest effective moisture with the establishment of seasonality between 5 and 3 cal ka BP. From 3 cal ka BP, the record indicates a retraction of the forest-steppe ecotone accompanied by a high pollen record variability and an increased fire activity. These late changes suggest decreased effective moisture associated with a high climatic variability. At regional and extra-regional scale, climatic changes at Lake Shaman's record are mostly associated to changes (latitudinal shifts and/or strengthening/weakening) of past Southern Westerlies that were previously recorded along Patagonia from the Lateglacial to the mid-Holocene. During the Late Holocene, a regional pattern characterized by high record variability emerges throughout Central Chilean Patagonia. This variability would be related to (1) low magnitude Southern Westerlies changes probably associated to ENSO and/or SAM or (2) the complex relationships between vegetation, fire and human occupations during the last 3 cal ka.

Development and exploitation of a controlled vocabulary in support of climate modelling

There are three key components for developing a metadata system: a container structure laying out the key semantic issues of interest and their relationships; an extensible controlled vocabulary providing possible content; and tools to create and manipulate that content. While metadata systems must allow users to enter their own information, the use of a controlled vocabulary both imposes consistency of definition and ensures comparability of the objects described. Here we describe the controlled vocabulary (CV) and metadata creation tool built by the METAFOR project for use in the context of describing the climate models, simulations and experiments of the fifth Coupled Model Intercomparison Project (CMIP5). The CV and resulting tool chain introduced here is designed for extensibility and reuse and should find applicability in many more projects.

Apolipoprotein e genotype has a modest impact on the postprandial plasma response to meals of varying fat composition in healthy men in a randomized controlled trial

BACKGROUND:Apolioprotein E (APOE) genotype is reported to influence a person's fasting lipid profile and potentially the response to dietary fat manipulation. The impact of APOE genotype on the responsiveness to meals of varying fat composition is unknown. OBJECTIVE:We examined the effect of meals containing 50 g of fat rich in saturated fatty acids (SFAs), unsaturated fatty acids (UNSATs), or SFAs with fish oil (SFA-FO) on postprandial lipemia. METHOD:A randomized, controlled, test meal study was performed in men recruited according to the APOE genotype (n = 10 APOE3/3, n = 11 APOE3/E4). RESULTS:For the serum apoE response (meal × genotype interaction P = 0.038), concentrations were on average 8% lower after the UNSAT than the SFA-FO meal in APOE4 carriers (P = 0.015) only. In the genotype groups combined, there was a delay in the time to reach maximum triacylglycerol (TG) concentration (mean ± SEM: 313 ± 25 vs. 266 ± 27 min) and higher maximum nonesterified fatty acid (0.73 ± 0.05 vs. 0.60 ± 0.03 mmol/L) and glucose (7.92 ± 0.22 vs. 7.25 ± 0.22 mmol/L) concentrations after the SFA than the UNSAT meal, respectively (P ≤ 0.05). In the Svedberg flotation rate 60-400 TG-rich lipoprotein fraction, meal × genotype interactions were observed for incremental area under the curve (IAUC) for the TG (P = 0.038) and apoE (P = 0.016) responses with a 58% lower apoE IAUC after the UNSAT than the SFA meal (P = 0.017) in the E4 carriers. CONCLUSIONS:Our data indicate that APOE genotype had a modest impact on the postprandial response to meals of varying fat composition in normolipidemic men. The physiologic importance of greater apoE concentrations after the SFA-rich meals in APOE4 carriers may reflect an impact on TG-rich lipoprotein clearance from the circulation. This trial was registered at clinicaltrials.gov as NCT01522482.

Does domperidone, a D2-antagonist alter gastric emptying rates and appetite sensations in healthy adults with high-fat meal? A block-randomised, single-blind placebo-controlled study

BACKGROUND: Accelerated gastric emptying (GE) may lead to reduced satiation, increased food intake and is associated with obesity and type 2 diabetes. Domperidone is a dopamine 2 (D(2)) receptor antagonist with claims of gastrointestinal tract pro-kinetic activity. In humans, domperidone is used as an anti-emetic and treatment for gastrointestinal bloating and discomfort. AIM: To determine the effect of acute domperidone administration on GE rate and appetite sensations in healthy adults. METHODS: A single-blind block randomised placebo-controlled crossover study assessed 13 healthy adults. Subjects ingested 10 mg domperidone or placebo 30 min before a high-fat (HF) test meal. GE rate was determined using the (13)CO(2) octanoic acid breath test. Breath samples and subjective appetite ratings were collected in the fasted and during the 360 min postprandial period. RESULTS:Gastric emptying half-time was similar following placebo (254 ± 54 min) and 10 mg domperidone (236 ± 65 min). Domperidone did not change appetite sensations during the 360 min postprandial period (P > 0.05). CONCLUSIONS: In healthy adults, acute administration of 10 mg domperidone did not change GE or appetite sensations following a HF test meal.

Global analysis of radiative forcing from fire-induced shortwave albedo change

Land surface albedo, a key parameter to derive Earth's surface energy balance, is used in the parameterization of numerical weather prediction, climate monitoring and climate change impact assessments. Changes in albedo due to fire have not been fully investigated on a continental and global scale. The main goal of this study, therefore, is to quantify the changes in instantaneous shortwave albedo produced by biomass burning activities and their associated radiative forcing. The study relies on the MODerate-resolution Imaging Spectroradiometer (MODIS) MCD64A1 burned-area product to create an annual composite of areas affected by fire and the MCD43C2 bidirectional reflectance distribution function (BRDF) albedo snow-free product to compute a bihemispherical reflectance time series. The approximate day of burning is used to calculate the instantaneous change in shortwave albedo. Using the corresponding National Centers for Environmental Prediction (NCEP) monthly mean downward solar radiation flux at the surface, the global radiative forcing associated with fire was computed. The analysis reveals a mean decrease in shortwave albedo of −0.014 (1σ = 0.017), causing a mean positive radiative forcing of 3.99 Wm−2 (1σ = 4.89) over the 2002–20012 time period in areas affected by fire. The greatest drop in mean shortwave albedo change occurs in 2002, which corresponds to the highest total area burned (378 Mha) observed in the same year and produces the highest mean radiative forcing (4.5 Wm−2). Africa is the main contributor in terms of burned area, but forests globally give the highest radiative forcing per unit area and thus give detectable changes in shortwave albedo. The global mean radiative forcing for the whole period studied (~0.0275 Wm−2) shows that the contribution of fires to the Earth system is not insignificant.

Operational active fire mapping and burnt area identification applicable to Mexican Nature Protection Areas using MODIS and NOAA-AVHRR direct readout data

Since 1999, the National Commission for the Knowledge and Use of the Biodiversity (CONABIO) in Mexico has been developing and managing the “Operational program for the detection of hot-spots using remote sensing techniques”. This program uses images from the MODerate resolution Imaging Spectroradiometer (MODIS) onboard the Terra and Aqua satellites and from the Advanced Very High Resolution Radiometer of the National Oceanic and Atmospheric Administration (NOAA-AVHRR), which are operationally received through the Direct Readout station (DR) at CONABIO. This allows the near-real time monitoring of fire events in Mexico and Central America. In addition to the detection of active fires, the location of hot spots are classified with respect to vegetation types, accessibility, and risk to Nature Protection Areas (NPA). Besides the fast detection of fires, further analysis is necessary due to the considerable effects of forest fires on biodiversity and human life. This fire impact assessment is crucial to support the needs of resource managers and policy makers for adequate fire recovery and restoration actions. CONABIO attempts to meet these requirements, providing post-fire assessment products as part of the management system in particular for satellite-based burnt area mapping. This paper provides an overview of the main components of the operational system and will present an outlook to future activities and system improvements, especially the development of a burnt area product. A special focus will also be placed on the fire occurrence within NPAs of Mexico

Design and baseline characteristics of the Food4Me study: a web-based randomised controlled trial of personalised nutrition in seven European countries

Improving lifestyle behaviours has considerable potential for reducing the global burden of non-communicable diseases, promoting better health across the life-course and increasing well-being. However, realising this potential will require the development, testing and implementation of much more effective behaviour change interventions than are used conventionally. Therefore, the aim of this study was to conduct a multi-centre, web-based, proof-of-principle study of personalised nutrition (PN) to determine whether providing more personalised dietary advice leads to greater improvements in eating patterns and health outcomes compared to conventional population-based advice. A total of 5,562 volunteers were screened across seven European countries; the first 1,607 participants who fulfilled the inclusion criteria were recruited into the trial. Participants were randomly assigned to one of the following intervention groups for a 6-month period: Level 0-control group-receiving conventional, non-PN advice; Level 1-receiving PN advice based on dietary intake data alone; Level 2-receiving PN advice based on dietary intake and phenotypic data; and Level 3-receiving PN advice based on dietary intake, phenotypic and genotypic data. A total of 1,607 participants had a mean age of 39.8 years (ranging from 18 to 79 years). Of these participants, 60.9 % were women and 96.7 % were from white-European background. The mean BMI for all randomised participants was 25.5 kg m(-2), and 44.8 % of the participants had a BMI ≥ 25.0 kg m(-2). Food4Me is the first large multi-centre RCT of web-based PN. The main outcomes from the Food4Me study will be submitted for publication during 2015.

Causal relationships vs. emergent patterns in the global controls of fire frequency

Global controls on month-by-month fractional burnt area (2000–2005) were investigated by fitting a generalised linear model (GLM) to Global Fire Emissions Database (GFED) data, with 11 predictor variables representing vegetation, climate, land use and potential ignition sources. Burnt area is shown to increase with annual net primary production (NPP), number of dry days, maximum temperature, grazing-land area, grass/shrub cover and diurnal temperature range, and to decrease with soil moisture, cropland area and population density. Lightning showed an apparent (weak) negative influence, but this disappeared when pure seasonal-cycle effects were taken into account. The model predicts observed geographic and seasonal patterns, as well as the emergent relationships seen when burnt area is plotted against each variable separately. Unimodal relationships with mean annual temperature and precipitation, population density and gross domestic product (GDP) are reproduced too, and are thus shown to be secondary consequences of correlations between different controls (e.g. high NPP with high precipitation; low NPP with low population density and GDP). These findings have major implications for the design of global fire models, as several assumptions in current models – most notably, the widely assumed dependence of fire frequency on ignition rates – are evidently incorrect.

Increased dietary α-linolenic acid has sex-specific effects upon eicosapentaenoic acid status in humans: re-examination of data from a randomised, placebo-controlled, parallel study

Background: There is a metabolic pathway by which mammals can convert the omega-3 (n-3) essential fatty acid α-linolenic acid (ALA) into longer-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). As far as we know there are currently no studies that have specifically examined sex differences in the LC n-3 PUFA response to increased dietary ALA intake in humans, although acute studies with isotope-labelled ALA identified that women have a significantly greater capacity to synthesise EPA and DHA from ALA compared to men. Findings: Available data from a placebo-controlled, randomised study were re-examined to identify whether there are sex differences in the LC n-3 PUFA response to increased dietary ALA intake in humans. There was a significant difference between sexes in the response to increased dietary ALA, with women having a significantly greater increase in the EPA content of plasma phospholipids (mean +2.0% of total fatty acids) after six months of an ALA-rich diet compared to men (mean +0.7%, P = 0.039). Age and BMI were identified as predictors of response to dietary ALA among women. Conclusions: Women show a greater increase in circulating EPA than men during increased dietary ALA consumption. Further understanding of individual variation in the response to dietary ALA could inform nutrition advice, with recommendations being specifically tailored according to habitual diet, sex, age and BMI.

Chronic consumption of flavanone-rich orange juice is associated with cognitive benefits: an 8-wk randomised, double-blind, placebo-controlled trial in healthy older adults

Background: Research indicates that chronic consumption of flavonoids is associated with cognitive benefits in adults with mild cognitive impairment and neurodegenerative disease, although, there has been no such studies in healthy older adults. Furthermore, the effects of commonly consumed orange juice flavanones on cognitive function remain unexplored. Objective: To investigate whether eight weeks of daily flavanone-rich orange juice consumption was beneficial for cognitive function in healthy older adults. Design: High flavanone (HF: 305mg) 100% orange juice and equicaloric low flavanone (LF: 37mg) orange flavored cordial (500ml) were consumed daily for eight weeks by thirty seven healthy older adults (mean age 67 years) according to a crossover, double blind, randomized design separated by a four week washout. Cognitive function, mood and blood pressure were assessed at baseline and follow up with standardized validated tests. Results: Global cognitive function was significantly better following eight week consumption of flavanone-rich juice relative to eight week consumption of the low flavanone control. No significant effects on mood or blood pressure were observed. Conclusions: Chronic daily consumption of flavanone-rich 100% orange juice over eight weeks is beneficial for cognitive function in healthy older adults. The potential for flavanone-rich foods and drinks to attenuate cognitive decline in ageing and the mechanisms which underlie these effects should be investigated.