Metabolic costs of force generation for constant-frequency and catchlike-inducing electrical stimulation in human tibialis anterior muscle

Metabolic costs of force generation were compared for constant-frequency and catchlike-inducing electrical stimulation. Repetitive catchlike-inducing trains consisted of 2 interpulse intervals (IPIs) at 12.5 ms, 1 IPI at 25 ms, and 5 IPIs at 50 ms. Constant-frequency trains consisted of 8 IPIs at 37.5 ms. One train was delivered to the peroneal nerve every 2.5 s for 36 times under ischemic conditions. Anaerobic adenosine triphosphate (ATP) turnover was determined using 31-phosphorus magnetic resonance spectroscopy (P-MRS) of the human tibialis anterior muscle. Compared with constant-frequency trains, catchlike-inducing trains produced a faster force generation and were more effective in maintaining the force--time integral as well as peak force. However, ATP costs of force generation were similar for the catchlike-inducing and constant-frequency stimulation (6.7 plus/minus 1.1 and 6.6 plus/minus 1.0 micromol ATP/kg wet weight/Ncenter dots, respectively, P = 0.601). This suggests that the positive effects of catchlike-inducing stimulation on force maintenance are mediated by potentiated Ca(2+) release from the sarcoplasmic reticulum rather than by lower metabolic costs of muscle force generation. Our findings also suggest that catchlike-inducing stimulation produces larger forces in fatigued muscle than constant-frequency trains and thus may be beneficial for muscle training or rehabilitation when muscle loading needs to be maintained in repetitive contractions.     

High-intensity exercise attenuates postprandial lipaemia and markers of oxidative stress

Regular exercise can reduce the risk of CVD (cardiovascular disease). Although moderate-intensity exercise can attenuate postprandial TAG (triacylglycerol), high-intensity intermittent exercise might be a more effective method to improve health. We compared the effects of high-intensity intermittent exercise and 30?min of brisk walking on postprandial TAG, soluble adhesion molecules and markers of oxidative stress. Nine men each completed three 2-day trials. On day 1, subjects rested (control), walked briskly for 30?min (walking) or performed 5×30?s maximal sprints (high-intensity). On day 2, subjects consumed a high-fat meal for breakfast and 3?h later for lunch. Blood samples were taken at various times and analysed for TAG, glucose, insulin, ICAM-1 (intracellular adhesion molecule-1), VCAM-1 (vascular adhesion molecule-1), TBARS (thiobarbituric acid- reactive substances), protein carbonyls and β-hydroxybutyrate. On day 2 of the high-intensity trial, there was a lower (P<0.05) incremental TAG AUC (area under the curve; 6.42±2.24?mmol/l per 7?h) compared with the control trial (9.68±4.77?mmol/l per 7?h) with no differences during day 2 of the walking trial (8.98±2.84?mmol/l per 7?h). A trend (P=0.056) for a reduced total TAG AUC was also seen during the high-intensity trial (14.13±2.83?mmol/l per 7?h) compared with control (17.18±3.92?mmol/l per 7?h), walking showed no difference (16.33±3.51?mmol/l per 7?h). On day 2 of the high-intensity trial plasma TBARS and protein carbonyls were also reduced (P<0.05) when compared with the control and walking trials. In conclusion, high-intensity intermittent exercise attenuates postprandial TAG and markers of oxidative stress after the consumption of a high-fat meal.     

Lanthanum and Manganese Co-Doping Effects on Structural,Morphological, and Magnetic Properties of Sol-Gel Derived BiFeO3

In this work, lanthanum and manganese co-substitution effects on different properties of bismuth ferrite solid solutions Bi_1-xLa_xFe_0.85Mn_0.15O₃ (x from 0 to 1) prepared by a sol-gel synthetic approach have been investigated. It was observed that the structural, morphological, and magnetic properties of obtained specimens are influenced by the amount of introduced La³⁺ ions. Surprisingly, only the compound with a composition of BiFe_0.85Mn_0.15O₃ was not monophasic, and the presence of neighboring phases was determined from X-ray diffraction analysis and Mössbauer measurements. Structural transitions from orthorhombic to cubic and back to orthorhombic were also observed depending on the La³⁺ amount. Antiferromagnetic behaviour was observed for all of the samples, with the highest magnetisation values for Bi_0.5La_0.5Fe_0.85Mn_0.15O₃. Additionally, structural attributes and morphological features were evaluated by Raman spectroscopy and scanning electron microscopy (SEM), respectively.     

Confronting and resolving competing values behind conservation objectives

Diverse motivations for preserving nature both inspire and hinder its conservation. Optimal conservation strategies may differ radically depending on the objective. For example, creating nature reserves may prevent extinctions through protecting severely threatened species, whereas incentivizing farmland hedgerows may benefit people through bolstering pest-eating or pollinating species. Win-win interventions that satisfy multiple objectives are alluring, but can also be elusive. To achieve better outcomes, we developed and implemented a practical typology of nature conservation framed around seven common conservation objectives. Using an intensively studied bird assemblage in southern Costa Rica as a case study, we applied the typology in the context of biodiversity’s most pervasive threat: habitat conversion. We found that rural habitats in a varied tropical landscape, comprising small farms, villages, forest fragments, and forest reserves, provided biodiversity-driven processes that benefit people, such as pollination, seed dispersal, and pest consumption. However, species valued for their rarity, endemism, and evolutionary distinctness declined in farmland. Conserving tropical forest on farmland increased species that international tourists value, but not species discussed in Costa Rican newspapers. Despite these observed trade-offs, our analyses also revealed promising synergies. For example, we found that maintaining forest cover surrounding farms in our study region would likely enhance most conservation objectives at minimal expense to others. Overall, our typology provides a framework for resolving the competing objectives of modern conservation.For at least the last century (1, 2), there has been fierce debate over whether nature should be conserved primarily to benefit people or for its own sake. Recently, conservation scientists and practitioners have called for the adoption of a more holistic and inclusive conservation ethic that accepts diverse motivations for conservation (3). In practice, however, limited funding and resources precipitate conflict between individuals and institutions with different motivations for conserving nature. Such conflicts often arise because the best intervention for achieving a chosen conservation objective may fail to achieve another. For example, the influential “biodiversity hotspots” concept directs conservation resources to areas with high rates of habitat loss and high densities of endemic species (4). But hotspots could be delineated using criteria related to virtually any conservation objective. Targeting conservation efforts only on hotspots of extinction or endemism could overlook other species and ecosystems that deliver vital benefits to people (e.g., wetlands that purify water and mitigate floods) (5, 6; but see ref. 7).Because conservationists have disparate and diverse values (8), measuring trade-offs is critical. A typology of conservation objectives could help identify trade-offs. In the past, scientists have created typologies to promote multiple components of biodiversity for monitoring and consideration in conservation decisions. For example, biodiversity has been divided across scales (α, β, and γ diversity) (9), into different species groupings (functional, phylogenetic, taxonomic, or morphological diversity) (10), and into compositional, structural, and functional attributes (11). Typologies have also been used to manage ecosystem services; for example, dividing services into “provisioning,” “regulating,” “cultural,” and “supporting” categories (12). A benefit of typologies is that multiple categories of biodiversity and ecosystem services can be analyzed simultaneously to identify and compare trade-offs. For example, one recent study reported low congruence between bird functional, phylogenetic, and taxonomic diversity, and underrepresentation of functional diversity in existing protected areas (13). Another showed that most regulating ecosystem services decline in areas where provisioning services increase (14).Early attempts to monitor and manage nature focused on developing indicators that reflected aspects of biodiversity that were widely valued (10, 15, 16). We drew from this work to define a typology for nature conservation that is explicitly linked to conservation objectives, rather than attributes of biodiversity or ecosystem services per se. Specifically, we delineated seven common objectives for nature conservation: (i) preventing global extinctions: extinction risk; (ii) conserving local populations or regional species pools: extirpation risk; (iii) preserving the legacy of past evolution by sustaining biodiversity across the tree of life (15, 17): evolution; (iv) restoring historic species assemblages: naturalness; (v) securing the flow of material resources from nature to people: provisioning services; (vi) maintaining ecological processes that benefit people: regulating services; and (vii) conserving species or landscapes of cultural significance: cultural services (

Spatial patterns of agricultural expansion determine impacts on biodiversity and carbon storage

The agricultural expansion and intensification required to meet growing food and agri-based product demand present important challenges to future levels and management of biodiversity and ecosystem services. Influential actors such as corporations, governments, and multilateral organizations have made commitments to meeting future agricultural demand sustainably and preserving critical ecosystems. Current approaches to predicting the impacts of agricultural expansion involve calculation of total land conversion and assessment of the impacts on biodiversity or ecosystem services on a per-area basis, generally assuming a linear relationship between impact and land area. However, the impacts of continuing land development are often not linear and can vary considerably with spatial configuration. We demonstrate what could be gained by spatially explicit analysis of agricultural expansion at a large scale compared with the simple measure of total area converted, with a focus on the impacts on biodiversity and carbon storage. Using simple modeling approaches for two regions of Brazil, we find that for the same amount of land conversion, the declines in biodiversity and carbon storage can vary two- to fourfold depending on the spatial pattern of conversion. Impacts increase most rapidly in the earliest stages of agricultural expansion and are more pronounced in scenarios where conversion occurs in forest interiors compared with expansion into forests from their edges. This study reveals the importance of spatially explicit information in the assessment of land-use change impacts and for future land management and conservation.Agriculture is a major contributor to land transformation and hence a threat to the levels of biodiversity and ecosystem services (ES) vital to human endeavors and from which agriculture itself benefits. Growth in agriculture continues to accelerate, and it is estimated that agricultural lands could occupy an additional 200–300 million ha globally (mostly in Latin America and sub-Saharan Africa) in the next 40 y (1). With such mounting pressure and so much at stake, it is essential to find ways to meet agricultural demand while conserving critical ecosystems and minimizing overall impacts. In response, influential actors such as corporations and governments are creating policies, initiatives, agreements and the like that determine how and where agricultural development occurs. Typically, the objectives of these activities are based on reducing the relative and/or total impact of agriculture through avoidance of areas of High Conservation Value (2, 3) or High Carbon Stock (4).Managing the demand for new agricultural land is undeniably important, and predictive modeling approaches for land development and management are urgently needed to better inform decision-making. Representation of the future for agriculture as a polarized choice between intensification and agricultural expansion is overly simplistic and unrealistic, especially given recent reports that yields of key commodities are saturating at levels far below that needed to meet increased demand (5). Future land development and management strategies will need to consider “land-sparing” approaches that consolidate and maximally intensify agriculture (6, 7) and “land-sharing” approaches that integrate natural and agricultural land into a more continuous mosaic (8, 9). It is likely that different strategies will work better in different places and at different scales, but questions about the optimal configuration and integration of agricultural and natural landscapes remain. To assess the impacts of future agricultural expansion at a landscape level, it is important to consider how and where such expansion may occur to understand resulting impacts on biodiversity and ES. Ecological theory suggests that the marginal value of the benefit provided by each unit of habitat conserved changes with the amount of total habitat area (10), and depending on the service, marginal values for the same type of habitat can vary widely based on its location relative to other habitat (11). Techniques for landscape optimization demonstrate the importance of where different land uses occur in determining the aggregate level of biodiversity or ES produced by a landscape (12).Recent advances in scientific understanding and data availability have improved our ability to predict the impacts of land-use change on the levels of biodiversity and ES at the landscape level and have enabled the development of spatially explicit models of these ecosystem processes under different landscape configurations (13, 14). Tools to model the spatial variation in land-use change impacts on biodiversity and ES, including InVEST (Integrated Valuation of Ecosystem Services and Trade-Offs) (15), GLOBIO (16), ARIES (17), and others, are now being used to help inform a wide range of decisions related to land-use planning, infrastructure investment, urban water supplies, and disaster risk reduction (18–21). In contrast to much of this site-based work often occurring in governmental decision contexts, considerations of biodiversity and ES by corporations and multilateral organizations typically rely on approaches that assign an amount of benefit or impact on a per-area basis, without representation of spatial variability (22). Global actors that indirectly or directly affect land use through sourcing decisions for commodity supply chains or investment decisions setting incentives for development would be better informed by approaches that could illustrate how their decisions play out across space.In this paper we examine the impact of different spatial patterns of agricultural expansion on biodiversity (a metric of the average species response, mean species abundance) (Methods) and carbon storage (above-ground and below-ground biomass) to determine the degree to which the impacts of agricultural expansion can be reduced simply by influencing the pattern of land conversion. Many other ES, notably the provision of water, but also pollination and pest control, are vitally important to the continued productivity of agriculture. All of these services, as well as agricultural productivity itself, are variable in their production over space and their response to land-use change and are therefore important to consider in this way as well. We focus on carbon and biodiversity here as a first step because they feature prominently in existing sustainability assessments and are often considered solely on a per-area basis. Our goal is to highlight the importance of considering not only the total area of agricultural expansion, but also where the expansion occurs, differentiating between agricultural decisions that spread a small amount of impact over many places and those that consolidate a larger impact in fewer places. Field evidence shows lower biodiversity in small patches of forest and lower carbon stored in forest edges (see Methods for more detail). Translating such site-based information to broader assessment approaches is necessary to understand the potential importance of spatial configuration to land-use change impacts.     

ATP economy of force maintenance in human tibialis anterior muscle

PURPOSE: The aim of this study was investigate ATP economy of force maintenance in the human tibialis anterior muscle during 60 s of anaerobic voluntary contraction at 50% of maximum voluntary contraction (MVC). METHODS: ATP turnover rate was evaluated using P magnetic resonance spectroscopy (P-MRS). The total volume of ankle dorsiflexor muscles was assessed by H magnetic resonance imaging (MRI) (H-MRI), and the fiber type composition of the tibialis anterior muscle was evaluated using histochemical analysis of muscle biopsies. RESULTS: The tibialis anterior muscle occupied 59.7 +/- 0.6% (mean +/- SEM) of the total ankle dorsiflexor muscle volume, which was 267 +/- 10 cm. Relative cross-sectional areas occupied by Type I, IIA, and IIB fibers in the tibialis anterior were 69.3 +/- 2.2, 27.4 +/- 2.76, and 3.2 +/- 1.0%, respectively. ATP economy of force maintenance did not change significantly during the 60-s contraction. It averaged at 4.81 +/- 0.42 N.s.micromol-1, and correlated with the relative cross-sectional area of the muscle occupied by Type I fiber (r = 0.73, P < 0.01). For the second half of the contraction, subjects dropping in force showed lower ATP economy compared with those maintaining the force (3.7 +/- 0.6 vs 5.3 +/- 0.6 N.s.micromol-1; P < 0.05). CONCLUSION: It is argued that the unchanged ATP economy of force maintenance during the voluntary contraction could be due to an increase in the ATP economy of contracting muscle fibers offsetting the effects of increased temperature and low ATP economy of Type II fibers. Mechanical interaction between motor units could also act to improve ATP economy of force maintenance.     

Crystal Structure and Concentration-Driven Phase Transitions in Lu(1−x)ScxFeO3 (0 ≤ x ≤ 1) Prepared by the Sol–Gel Method

The structural state and crystal structure of Lu_(1−x)Sc_xFeO₃ (0 ≤ x ≤ 1) compounds prepared by a chemical route based on a modified sol–gel method were investigated using X-ray diffraction, Raman spectroscopy, as well as scanning electron microscopy. It was observed that chemical doping with Sc ions led to a structural phase transition from the orthorhombic structure to the hexagonal structure via a wide two-phase concentration region of 0.1 < x < 0.45. An increase in scandium content above 80 mole% led to the stabilization of the non-perovskite bixbyite phase specific for the compound ScFeO₃. The concentration stability of the different structural phases, as well as grain morphology, were studied depending on the chemical composition and synthesis conditions. Based on the data obtained for the analyzed samples, a composition-dependent phase diagram was constructed.     

Bone mineral density and risk of cardiovascular disease in men and women: the HUNT study

European Journal of Epidemiology - The association between bone mineral density (BMD) and cardiovascular disease (CVD) is not fully understood. We evaluated BMD as a risk factor for cardiovascular...     

Improving global environmental management with standard corporate reporting

Multinational corporations play a prominent role in shaping the environmental trajectory of the planet. The integration of environmental costs and benefits into corporate decision-making has enormous, but as yet unfulfilled, potential to promote sustainable development. To help steer business decisions toward better environmental outcomes, corporate reporting frameworks need to develop scientifically informed standards that consistently consider land use and land conversion, clean air (including greenhouse gas emissions), availability and quality of freshwater, degradation of coastal and marine habitats, and sustainable use of renewable resources such as soil, timber, and fisheries. Standardization by itself will not be enough—also required are advances in ecosystem modeling and in our understanding of critical ecological thresholds. With improving ecosystem science, the opportunity for realizing a major breakthrough in reporting corporate environmental impacts and dependencies has never been greater. Now is the time for ecologists to take advantage of an explosion of sustainability commitments from business leaders and expanding pressure for sustainable practices from shareholders, financial institutions, and consumers.