Математична залежність точності верстатних пристроїв від їх ступеня гнучкості

Підвищення конкурентоспроможності продукції, що виробляється невеликими підприємствами, забезпечується шляхом скорочення витрат на проектування та виготовлення технологічної оснастки для свердлильно- фрезерно-розточувальних операцій. Це стає можливим за рахунок використання гнучких верстатних пристроїв (ВП), що мають можливість переналагодження у заданому діапазоні розмірів заготовки шляхом регулювання установлювально-затискних елементів

Extensive dissolution of live pteropods in the Southern Ocean

The carbonate chemistry of the surface ocean is rapidly changing with ocean acidification, a result of human activities. In the upper layers of the Southern Ocean, aragonite—a metastable form of calcium carbonate with rapid dissolution kinetics—may become undersaturated by 2050 (ref. 2). Aragonite undersaturation is likely to affect aragonite-shelled organisms, which can dominate surface water communities in polar regions. Here we present analyses of specimens of the pteropod Limacina helicina antarctica that were extracted live from the Southern Ocean early in 2008. We sampled from the top 200m of the water column, where aragonite saturation levels were around 1, as upwelled deep water is mixed with surface water containing anthropogenic CO2. Comparing the shell structure with samples from aragonite-supersaturated regions elsewhere under a scanning electron microscope, we found severe levels of shell dissolution in the undersaturated region alone. According to laboratory incubations of intact samples with a range of aragonite saturation levels, eight days of incubation in aragonite saturation levels of 0.94– 1.12 produces equivalent levels of dissolution. As deep-water upwelling and CO2 absorption by surface waters is likely to increase as a result of human activities2,4, we conclude that upper ocean regions where aragonite-shelled organisms are affected by dissolution are likely to expand

The global carbon budget 1959-2011

Accurate assessments of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the climate policy process, and project future climate change. Present-day analysis requires the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. Here we describe datasets and a methodology developed by the global carbon cycle science community to quantify all major components of the global carbon budget, including their uncertainties. We discuss changes compared to previous estimates, consistency within and among components, and methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF) are based on energy statistics, while emissions from Land-Use Change (ELUC), including deforestation, are based on combined evidence from land cover change data, fire activity in regions undergoing deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. Finally, the global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms. For the last decade available (2002–2011), EFF was 8.3 ± 0.4 PgC yr−1, ELUC 1.0 ± 0.5 PgC yr−1, GATM 4.3 ± 0.1PgC yr−1, SOCEAN 2.5 ± 0.5 PgC yr−1, and SLAND 2.6 ± 0.8 PgC yr−1. For year 2011 alone, EFF was 9.5 ± 0.5 PgC yr−1, 3.0 percent above 2010, reflecting a continued trend in these emissions; ELUC was 0.9 ± 0.5 PgC yr−1, approximately constant throughout the decade; GATM was 3.6 ± 0.2 PgC yr−1, SOCEAN was 2.7 ± 0.5 PgC yr−1, and SLAND was 4.1 ± 0.9 PgC yr−1. GATM was low in 2011 compared to the 2002–2011 average because of a high uptake by the land probably in response to natural climate variability associated to La Niña conditions in the Pacific Ocean. The global atmospheric CO2 concentration reached 391.31 ± 0.13 ppm at the end of year 2011. We estimate that EFF will have increased by 2.6% (1.9–3.5%) in 2012 based on projections of gross world product and recent changes in the carbon intensity of the economy. All uncertainties are reported as ±1 sigma (68% confidence assuming Gaussian error distributions that the real value lies within the given interval), reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. This paper is intended to provide a baseline to keep track of annual carbon budgets in the future

Variability in efficiency of particulate organic carbon export: A model study

The flux of organic carbon from the surface ocean to mesopelagic depths is a key component of the global carbon cycle and is ultimately derived from primary production (PP) by phytoplankton. Only a small fraction of organic carbon produced by PP is exported from the upper ocean, referred to as the export efficiency (herein e-ratio). Limited observations of the e-ratio are available and there is thus considerable interest in using remotely-sensed parameters such as sea surface temperature to extrapolate local estimates to global annual export flux. Currently, there are large discrepancies between export estimates derived in this way; one possible explanation is spatial or temporal sampling bias in the observations. Here we examine global patterns in the spatial and seasonal variability in e-ratio and the subsequent effect on export estimates using a high resolution global biogeochemical model. NEMO-MEDUSA represents export as separate slow and fast sinking detrital material whose remineralisation is respectively temperature dependent and a function of ballasting minerals. We find that both temperature and the fraction of export carried by slow sinking particles are factors in determining e-ratio, suggesting that current empirical algorithms for e-ratio that only consider temperature are overly simple. We quantify the temporal lag between PP and export, which is greatest in regions of strong variability in PP where seasonal decoupling can result in large e-ratio variability. Extrapolating global export estimates from instantaneous measurements of e-ratio is strongly affected by seasonal variability, and can result in errors in estimated export of up to ±60%

The Copenhagen Diagnosis: Updating the World on the Latest Climate Science

The Copenhagen Diagnosis is a summary of the global warming peer reviewed science since 2007. Produced by a team of 26 scientists led by the University of New South Wales Climate Research Centre, the Diagnosis convincingly proves that the effects of global warming have gotten worse in the last three years. It is a timely update to the UN’s Intercontinental Panel on Climate Change 2007 Fourth Assessment document (IPCC AR4). The report places the blame for the century long temperature increase on human factors and says the turning point ";must come soon";. If we are to limit warming to 2 degrees above pre-industrial values, global emissions must peak by 2020 at the latest and then decline rapidly. The scientists warned that waiting for higher levels of scientific certainty could mean that some tipping points will be crossed before they are recognized. By 2050 we will effectively need to be in a post-carbon economy if we are to avoid unlivable temperatures

A re-evaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean

We report a new synthesis of best estimates of the inputs of fixed nitrogen to the world ocean via atmospheric deposition, and compare this to fluvial inputs and di-nitrogen fixation. We evaluate the scale of human perturbation of these fluxes. Fluvial inputs dominate inputs to the continental shelf, and we estimate about 75% of this fluvial nitrogen escapes from the shelf to the open ocean. Biological di-nitrogen fixation is the main external source of nitrogen to the open ocean, i.e. beyond the continental shelf. Atmospheric deposition is the primary mechanism by which land based nitrogen inputs, and hence human perturbations of the nitrogen cycle, reach the open ocean. We estimate that anthropogenic inputs are currently leading to an increase in overall ocean carbon sequestration of ~0.4% (equivalent to an uptake of 0.15 Pg C yr-1 and less than the Duce et al., 2008 estimate). The resulting reduction in climate change forcing from this ocean CO2 uptake is offset to a small extent by an increase in ocean N2O emissions. We identify four important feedbacks in the ocean atmosphere nitrogen system that need to be better quantified to improve our understanding of the perturbation of ocean biogeochemistry by atmospheric nitrogen inputs. These feedbacks are recycling of (1) ammonia and (2) organic nitrogen from the ocean to the atmosphere and back, (3) the suppression of nitrogen fixation by increased nitrogen concentrations in surface waters from atmospheric deposition, and (4) increased loss of nitrogen from the ocean by denitrification due to increased productivity stimulated by atmospheric inputs

Regaining momentum for international climate policy beyond Copenhagen

The 'Copenhagen Accord' fails to deliver the political framework for a fair, ambitious and legally-binding international climate agreement beyond 2012. The current climate policy regime dynamics are insufficient to reflect the realities of topical complexity, actor coalitions, as well as financial, legal and institutional challenges in the light of extreme time constraints to avoid 'dangerous' climate change of more than 2°C. In this paper we analyze these stumbling blocks for international climate policy and discuss alternatives in order to regain momentum for future negotiations

Expression analysis of Clavata1-like and Nodulin21-like genes from Pinus sylvestris during ectomycorrhiza formation

The ecology and physiology of ectomycorrhizal (EcM) symbiosis with conifer trees are well documented. In comparison, however, very little is known about the molecular regulation of these associations. In an earlier study, we identified three EcM-regulated Pinus expressed sequence tags (EST), two of which were identified as homologous to the Medicago truncatula nodulin MtN21. The third EST was a homologue to the receptor-like kinase Clavata1. We have characterized the expression patterns of these genes and of auxin- and mycorrhiza-regulated genes after induction with indole-3-butyric acid in Pinus sylvestris and in a time course experiment during ectomycorrhizal initiation with the co-inoculation of 2,3,5-triiodobenzoic acid, an auxin transport inhibitor. Our results suggest that different P. sylvestris nodulin homologues are associated with diverse processes in the root. The results also suggest a potential role of the Clv1-like gene in lateral root initiation by the ectomycorrhizal fungus

Dynamics of global forest area: Results from the FAO Global Forest Resources Assessment 2015

The area of land covered by forest and trees is an important indicator of environmental condition. This study presents and analyses results from the Global Forest Resources Assessment 2015 (FRA 2015) of the Food and Agriculture Organization of the United Nations. FRA 2015 was based on responses to surveys by individual countries using a common reporting framework, agreed definitions and reporting standards. Results indicated that total forest area declined by 3%, from 4128 M ha in 1990 to 3999 M ha in 2015. The annual rate of net forest loss halved from 7.3 M ha y−1 in the 1990s to 3.3 M ha y−1 between 2010 and 2015. Natural forest area declined from 3961 M ha to 3721 M ha between 1990 and 2015, while planted forest (including rubber plantations) increased from 168 M ha to 278 M ha. From 2010 to 2015, tropical forest area declined at a rate of 5.5 M ha y−1 – only 58% of the rate in the 1990s – while temperate forest area expanded at a rate of 2.2 M ha y−1. Boreal and sub-tropical forest areas showed little net change. Forest area expanded in Europe, North America, the Caribbean, East Asia, and Western-Central Asia, but declined in Central America, South America, South and Southeast Asia and all three regions in Africa. Analysis indicates that, between 1990 and 2015, 13 tropical countries may have either passed through their forest transitions from net forest loss to net forest expansion, or continued along the path of forest expansion that follows these transitions. Comparing FRA 2015 statistics with the findings of global and pan-tropical remote-sensing forest area surveys was challenging, due to differences in assessment periods, the definitions of forest and remote sensing methods. More investment in national and global forest monitoring is needed to provide better support for international initiatives to increase sustainable forest management and reduce forest loss, particularly in tropical countries