670 research outputs found

    Linking meteorites to their asteroid parent bodies: The capabilities of dust analyzer instruments during asteroid flybys

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    Linking meteorites to their asteroid parent bodies remains an outstanding issue. Space-based dust characterization using impact ionization mass spectrometry is a proven technique for the compositional analysis of individual cosmic dust grains. Here we investigate the feasibility of determining asteroid compositions via cation mass spectrometric analyses of their dust ejecta clouds during low (7–9 km s−1) velocity spacecraft flybys. At these speeds, the dust grain mass spectra are dominated by easily ionized elements and molecular species. Using known bulk mineral volume abundances, we show that it is feasible to discriminate the common meteorite classes of carbonaceous chondrites, ordinary chondrites, and howardite–eucrite–diogenite achondrites, as well as their subtypes, relying solely on the detection of elements with ionization efficiencies of ≤700 or ≤800 kJ mol−1, applicable to low (~7 km s−1) and intermediate (~9 km s−1) flyby speed scenarios, respectively. Including the detection of water ion groups enables greater discrimination between certain meteorite types, and flyby speeds ≥10 km s−1 enhance the diagnostic capabilities of this technique still further. Although additional terrestrial calibration is required, this technique may allow more unequivocal asteroid-meteorite connections to be determined by spacecraft flybys, emphasizing the utility of dust instruments on future asteroid missions

    How Effective is the Invisible Hand? Agricultural and Food Markets in Central and Eastern Europe

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    Since the seminal work of Adam Smith, markets have been considered an efficient tool for co-ordinating the behaviour of economic agents. The basic characteristic of a market economy is that the complex system of interaction among individuals is not centrally coordinated. Under the assumption of profit and utility maximisation (and a whole set of assumptions about the institutional framework), relative prices and their change over time provide the signals that guide, like an invisible hand, the allocation of resources, i.e., the structure of production and the intensity of input use in the various production processes. They do this by co-ordinating the activities of economic agents, i.e., of resource owners, producers, intermediaries, traders, and consumers. After system change in the former Soviet Union and in Central and Eastern Europe (CEE) central economic planning had to be replaced by other forms of co-ordination. The general direction in all transition countries was towards a market economy, but the speed and depth of reforms towards an environment in which markets can evolve differed largely between countries, sectors and between different phases during the past 15 years. IAMO Forum 2005 focuses on this development and discusses the functioning of markets, the requirements for this, and the advantages and disadvantages of other co-ordination mechanisms under different environments in the agricultural and food sectors in Central and Eastern Europe. CEE agri-food markets deserve researchers' and policy makers' attention for several reasons. Two of them regard the high demand for support to policy decisions that aim to stimulate economic and social development in the region. In most CEE countries, the significance of the agricultural and food sector is relatively high with respect to income and employment. In particular, rural areas can benefit from the development of this branch of the economy. Also, there is marked indication that agri-food markets in CEE are not ensuring exchange as frictionless as possible. This means that large benefits can be expected if potential improvements of the economic environment are implemented and if individual agents adapt optimally to that environment. Another motivation for economic research on transition countries is that we are looking at a huge region that started almost as a vacuum with regard to institutional settings. This means that a wide range of substantially different settings were introduced in the respective countries, and were only weakly confined by political rigidities or path dependencies. From a distant perspective, the repeated fundamental shifts in recent economic policies almost evoke the impression of a trial and error approach. The consequences of distinctively different options (across countries and periods) can be observed in a way almost similar to a laboratory situation. Such unique opportunity has attracted economists, particularly those interested in institutional economics, to conduct research on CEE. However, this also means that the experiences made in CEEC can enhance the general understanding of what markets can do and what the limitations of market coordination are. This volume contains selected contributions presented at IAMO Forum 2005 and gives an overview of the major topics discussed there. Partial analyses of specific economic problems usually abstract from the general economic framework which is assumed to be more or less constant as expressed in ceteris paribus clauses. Oftentimes, the set of institutional conditions is even assumed to be sufficiently well-described by the framework used in neoclassical models. Particularly for transition countries, this has frequently led to spurious results because crucial aspects of the framework actually in place were not considered, and sometimes were not even thought of. An extreme and very obvious example is the neglect of the effects of the replacement of monetary by nonmonetary exchange in phases of a barter economy. There is no generic approach to avoid unintended omission of crucial framework conditions, but it must generally be emphasised that a broad look at the various interdependent markets and at the entire socioeconomic context of a country is needed before going into detail. Descriptive analyses of the situation in various markets form part of such a broad look. The contributions of POPP, FERTÃ et al., WILKIN et al., and HEIN in the chapter Selected analyses from CEEC provide excellent examples, and focus on market developments in new EU member countries. On the one hand, the papers show the heterogeneity of problems e.g. due to largely differing farm structures. On the other hand, several common patterns can be observed: The market shares and power of large processors and retailers (hypermarkets, etc.) are increasing. Also, international (especially intra-EU) trade in commodities has increased in response to CAP-induced price harmonisation. Both tendencies weaken the market position of farmers, particularly small entities which cannot supply in volumes sufficient for large processing and trade firms. Within the food industry concentration increased as many smaller firms could not comply with EU processing standards and had to quit the market. The increased size and specialization of large producers, as well as of large processors, made many of those firms co-ordinate business with each other through long-term contractual agreements rather than by relying on spot markets. This tendency is very distinct in the fruit and vegetable sector, as WILKINâs contribution describes. Two contributions draw attention to the institutional framework itself, mainly by looking at circumstances which prevent market allocation from leading to an optimal outcome. HOBBS describes factors that impede investment and growth by drawing on transaction cost economics. Situations typical for transition countries are highlighted where e.g. transparency is not sufficient or the existence and reliable enforcement of contract or corporate law are not guaranteed. NUPPENAU stresses the need for the appropriate and precise formulation of land property rights, which should evoke a balance between governance and exclusion. The importance of appropriate and reliable institutions to avoid flaws is emphasised. But even with suitable institutions, transaction costs cannot be reduced to zero. The main reason for this is that since agents may gain form a head start of information, incentives to reveal their knowledge are quite restricted. Furthermore, some of the information required to make correct decisions is not available. This especially concerns information regarding all future contingencies. An uncertain future and the asymmetric distribution of information impose special problems when decisions have long-term effects and agents are linked together through investment decisions. This offers possibilities for opportunistic behaviour, i.e., when an agent behaves in a way that allows him to extract rents from the partners' activities. The friction induced in such situations may result in a market outcome that is biased by transaction costs. Mitigating this bias should be a goal of public policy but it is also in the interest of (at least some of the) private agents involved. This issue is discussed in more detail in the papers dealing with alternative governance structures. A number of contributions to IAMO Forum highlight approaches for measuring the well-functioning of markets. While studies that aim to directly measure transaction costs are very rare and are necessarily limited to comparing only very specific portions of transaction costs, most studies focus on indirect indicators. These usually start from the idea that in a well-functioning, competitive market any supply or demand shocks are reflected in price changes, not only in the particular market where the shock occurs but also in other, related markets, i.e., in different locations or at different stages of the production and marketing chain. Consequently, an approach for assessing the functioning of markets is to compare price differentials with processing-, marketing- or transfer-costs, or â since these costs are usually difficult to quantify â to observe price differentials over time. Accepting the assumption that the costs reflected by price differentials are more or less constant (or stationary) over the observed time span, any additional price changes or a lack of price co-movement is interpreted as an indication for insufficiently connected or insufficiently functioning markets. Three contributions in the chapter Analytical approaches for measuring market efficiency describe analyses which mainly focus on the vertical dimension, i.e., between market stages. BOJNEC, in his descriptive price analysis for several agricultural products in Slovenia since 1991, finds a heterogeneous development of the farm gate/consumer price spread: The processing and marketing margins increased for wheat and beef while they declined for grapes (processed to wine), sugar and poultry. BRÃMMER and ZORYA, as well as BAKUCS and FERTÃ, use cointegration analysis to describe the degree and nature of vertical price integration in the Ukrainian wheat market and the Hungarian pork market, respectively. Both studies find that price changes are transmitted vertically, that there is a tendency to "correct" any deviations from some underlying equilibrium price-relationship. However, such error correction mechanisms are found not to be a constant, universal force. In the Hungarian paper, it could only be found for a sub-period of the observed time span, excluding the highly volatile early 1990s. Also, equilibrium was found to be achieved by adjustment of farm gate prices only while the retail prices were found to be exogenous, i.e., not responding to any disequilibrium. The paper on Ukraine shows that adjustment processes between wheat and wheat flour prices cannot be sufficiently described by a constant error correction mechanism for the period 2000 to 2004. In fact, four different regimes of adjustment processes were found to have been in force, reflecting particular phases of largely differing market situations and political interventions. The functioning of markets depends on several crucial conditions. One of these conditions concerns the availability of information. Only if agents have perfect and complete information will the exchange lead to an outcome in which no individual can be better off without reducing the welfare of others. However, in the real world this condition regarding information is not fulfilled. Information is not perfect, since the future cannot be predicted with certainty. Incomplete information results from, first, not all information being revealed, and second, individuals not possessing the mental capacity to collect and process all information. Moreover, because of its asymmetric distribution, information can be regarded as a resource that can be exploited by agents. This means that there are incentives to hamper the diffusion of information to the public domain. In general, the more uncertain the future is and the more information is tacit, the worse markets will function, and the more beneficial become alternative mechanisms of coordination. Three papers dealing with this issue of organisational choice. HANF focuses on governance structures within supply chain networks that are appropriate for allowing an optimal flow of information between the involved individuals while retaining the necessary hierarchy for efficient implementation of strategic decisions. MAACKâs analysis shows that there is strong mutual interest between producers and processors of berry fruits to reduce marketing and procurement risk, respectively. This can be achieved by switching from spot market exchange to contractual supply agreements. A prerequisite for such agreements is that a well-balanced distribution of risks and risk premiums between the farmer and processor is implemented. This means that processors, who â facing a multitude of small producers â are used to opportunities for exerting market power, have to agree to cover part of the production risk through appropriate contractual clauses. Finally, BALINT looks at the various marketing channels used by Romanian farmers and finds that a self-enforcing dualism exists. For commercially-oriented farmers who can supply large quantities, marketing directly to traders, wholesalers and processors is most favourable and involves relatively low transaction costs. Although this form of supply-relationship is usually not based on contractual agreements, it can still be characterised by a certain stability over time. In contrast, small farmers whose production does not considerably exceed the subsistence level incur relatively high (per unit) transaction costs in selling their produce on local markets and to other farmers. Another aspect of organisational choice is the question of whether ownership of production factors is transferred or only the right to use them temporarily. The uncertainty of future developments implies that the possession of resources cannot be only regarded from the point of view of income generation at a certain point in time. With perfect foresight, there is no difference whether a factor is rented or purchased, because the remuneration would be the same. This perfect substitutability is no longer given when the future is uncertain. Income generation, then, is only one feature of ownership. Additional aspects such as insurance, wealth, and speculation as motivations for possession affect the value of ownership and thus shift the demand and supply curves of the factor. HURRELMAN picks up this issue in her analysis of the Polish land market and shows the impact of additional grounds for valuing property on the decision to rent or to buy land. Uncertainty may also affect the specialization of factor use. Allocating a factor of production to different production activities reduces the risk of income instabilities, but at the cost of specialization gains through economics of scale. Moreover, the decision on income combination is â besides risk â affected by a complex interaction of other determinants. GLAUBEN et al., analyse these interactions for the case of part-time farming in China and show how the decision of income combination is affected by household characteristics, human capital and other variables. Incomplete and imperfect information not only causes individuals to choose optimal governance modes, often it is also understood as a call for government intervention. The selected papers in the chapter on policy intervention plead for careful selection and coherent implementation of policy instruments. BENNER, as well as KUHN, highlight the significance of information diffusion and argue in favour of government intervention in this area. However, both emphasise that these interferences should be used carefully and be adjusted to specific market failures. Both argue that setting up information systems would improve the functioning of markets. BENNER also discusses possible negative impacts if governments that engage in setting up and enforcing product and process standards try, at the same time, to foster a sector like agriculture through support in marketing. The latter activity affects the governmentâs (crucial) credibility in the first activity. KUHN points to negative welfare effects and budgetary requirements of an intervention system which is implemented to increase price stability. Moreover, when a government intervenes in market allocation or intends to provide rules that should facilitate the exchange on markets, it has to take into account that the new regulation has to be implemented in a coherent manner. This requires the various policy regulations and institutional settings to be complementary and not cause frictions which hamper the functioning of the system. LERMAN and SHAGAIDA highlight this aspect in their discussion of the Russian land market, where bureaucracy and high costs for the registration of property rights can be regarded as a major cause of the low number of land transactions. However, since economic activities take place in a dynamic environment, the comparative static point of view may lead to inappropriate policy formulation. WANDEL discusses this aspect in the context of competition policy. From a comparative static point of view, market power has to be assessed negatively because of the distortions of resource allocation. However, monopoly profits are an indicator of extra rents and thus provide incentives for market entry. On the one hand, this thread may lead to special pricing schemes and/or to the accelerated development of technological change so that a monopolist can consolidate its market position. But it is possible, on the other hand, that market entry may in fact happen. In this case, one would observe structural change, which would be accompanied by an improved use of resources. This in turn means that competition policy should not be oriented towards an optimal market structure but towards the facilitation of market entry so that competition can discover market opportunities and determine the optimal structure of the market. The present volume shows the wide range of interesting and controversial topics that are concerned when looking at co-ordination, particularly on markets in CEE agri-food sectors. It remains a hope that the heterogeneity and dynamics of the developments will decrease as successful constellations of framework conditions, organisational choices and individual behaviour become more and more obvious and widespread in the region. Conversion to sustainable, balanced patterns might take place, but this cannot be taken for granted. However, chances for such development are better the more stable and balanced political developments, as well as international co-operation, become. We hope that the academic community will contribute towards such goal.Agribusiness, Community/Rural/Urban Development, Industrial Organization, International Development, Labor and Human Capital, Land Economics/Use, Political Economy,

    Automated Cancer Diagnostics via Analysis of Optical and Chemical Images by Deep and Shallow Learning

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    Funding Information: The Icelandic Centre for Research, grant no. 174566051 & 207301. The Icelandic Breast Cancer Research Fund, Göngum Saman. CRUK GC, NIHR/Imperial BRC. Dr Jean Alero Thomas Scholarship. Funding Information: Funding: The Icelandic Centre for Research, grant no. 174566051 & 207301. The Icelandic Breast Cancer Research Fund, Göngum Saman. CRUK GC, NIHR/Imperial BRC. Dr Jean Alero Thomas Scholarship. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Optical microscopy has long been the gold standard to analyse tissue samples for the diagnostics of various diseases, such as cancer. The current diagnostic workflow is time-consuming and labour-intensive, and manual annotation by a qualified pathologist is needed. With the ever-increasing number of tissue blocks and the complexity of molecular diagnostics, new approaches have been developed as complimentary or alternative solutions for the current workflow, such as digital pathology and mass spectrometry imaging (MSI). This study compares the performance of a digital pathology workflow using deep learning for tissue recognition and an MSI approach utilising shallow learning to annotate formalin-fixed and paraffin-embedded (FFPE) breast cancer tissue microarrays (TMAs). Results show that both deep learning algorithms based on conventional optical images and MSI-based shallow learning can provide automated diagnostics with F1-scores higher than 90%, with the latter intrinsically built on biochemical information that can be used for further analysis.Peer reviewe

    A divergent heritage for complex organics in Isheyevo lithic clasts

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    Primitive meteorites are samples of asteroidal bodies that contain a high proportion of chemically complex organic matter (COM) including prebiotic molecules such as amino acids, which are thought to have been delivered to Earth via impacts during the early history of the Solar System. Thus, understanding the origin of COM, including their formation pathway(s) and environment(s), is critical to elucidate the origin of life on Earth as well as assessing the potential habitability of exoplanetary systems. The Isheyevo CH/CBb carbonaceous chondrite contains chondritic lithic clasts with variable enrichments in 15N believed to be of outer Solar System origin. Using transmission electron microscopy (TEM-EELS) and in situ isotope analyses (SIMS and NanoSIMS), we report on the structure of the organic matter as well as the bulk H and N isotope composition of Isheyevo lithic clasts. These data are complemented by electron microprobe analyses of the clast mineral chemistry and bulk Mg and Cr isotopes obtained by inductively coupled plasma and thermal ionization mass spectrometry, respectively (MC-ICPMS and TIMS). Weakly hydrated (A) clasts largely consist of Mg-rich anhydrous silicates with local hydrated veins composed of phyllosilicates, magnetite and globular and diffuse organic matter. Extensively hydrated clasts (H) are thoroughly hydrated and contain Fe-sulfides, sometimes clustered with organic matter, as well as magnetite and carbonates embedded in a phyllosilicate matrix. The A-clasts are characterized by a more 15N-rich bulk nitrogen isotope composition (δ15N = 200–650‰) relative to H-clasts (δ15N = 50–180‰) and contain extremely 15N-rich domains with δ15N 15N-rich domains show that the lithic clast diffuse organic matter is typically more 15N-rich than globular organic matter. The correlated δ15N values and C/N ratios of nanoglobules require the existence of multiple organic components, in agreement with the H isotope data. The combined H and N isotope data suggest that the organic precursors of the lithic clasts are defined by an extremely 15N-poor (similar to solar) and D-rich component for H-clasts, and a moderately 15N-rich and D-rich component for A-clasts. In contrast, the composition of the putative fluids is inferred to include D-poor but moderately to extremely 15N-rich H- and N-bearing components. The variable 15N enrichments in H- and A-clasts are associated with structural differences in the N bonding environments of their diffuse organic matter, which are dominated by amine groups in H-clasts and nitrile functional groups in A-clasts. We suggest that the isotopically divergent organic precursors in Isheyevo clasts may be similar to organic moieties in carbonaceous chondrites (CI, CM, CR) and thermally recalcitrant organic compounds in ordinary chondrites, respectively. The altering fluids, which are inferred to cause the 15N enrichments observed in the clasts, may be the result of accretion of variable abundances of NH3 and HCN ices. Finally, using bulk Mg and Cr isotope composition of clasts, we speculate on the accretion regions of the various primitive chondrites and components and the origin of the Solar System’s N and H isotope variability

    Synergies between interstellar dust and heliospheric science with an Interstellar Probe

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    We discuss the synergies between heliospheric and dust science, the open science questions, the technological endeavors and programmatic aspects that are important to maintain or develop in the decade to come. In particular, we illustrate how we can use interstellar dust in the solar system as a tracer for the (dynamic) heliosphere properties, and emphasize the fairly unexplored, but potentially important science question of the role of cosmic dust in heliospheric and astrospheric physics. We show that an Interstellar Probe mission with a dedicated dust suite would bring unprecedented advances to interstellar dust research, and can also contribute-through measuring dust - to heliospheric science. This can, in particular, be done well if we work in synergy with other missions inside the solar system, thereby using multiple vantage points in space to measure the dust as it `rolls' into the heliosphere. Such synergies between missions inside the solar system and far out are crucial for disentangling the spatially and temporally varying dust flow. Finally, we highlight the relevant instrumentation and its suitability for contributing to finding answers to the research questions.Comment: 18 pages, 7 Figures, 5 Tables. Originally submitted as white paper for the National Academies Decadal Survey for Solar and Space Physics 2024-203

    Timing the Landmark Events in the Evolution of Clear Cell Renal Cell Cancer: TRACERx Renal.

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    Clear cell renal cell carcinoma (ccRCC) is characterized by near-universal loss of the short arm of chromosome 3, deleting several tumor suppressor genes. We analyzed whole genomes from 95 biopsies across 33 patients with clear cell renal cell carcinoma. We find hotspots of point mutations in the 5' UTR of TERT, targeting a MYC-MAX-MAD1 repressor associated with telomere lengthening. The most common structural abnormality generates simultaneous 3p loss and 5q gain (36% patients), typically through chromothripsis. This event occurs in childhood or adolescence, generally as the initiating event that precedes emergence of the tumor's most recent common ancestor by years to decades. Similar genomic changes drive inherited ccRCC. Modeling differences in age incidence between inherited and sporadic cancers suggests that the number of cells with 3p loss capable of initiating sporadic tumors is no more than a few hundred. Early development of ccRCC follows well-defined evolutionary trajectories, offering opportunity for early intervention

    Urbanisation generates multiple trait syndromes for terrestrial animal taxa worldwide

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    Cities can host significant biological diversity. Yet, urbanisation leads to the loss of habitats, species, and functional groups. Understanding how multiple taxa respond to urbanisation globally is essential to promote and conserve biodiversity in cities. Using a dataset encompassing six terrestrial faunal taxa (amphibians, bats, bees, birds, carabid beetles and reptiles) across 379 cities on 6 continents, we show that urbanisation produces taxon-specific changes in trait composition, with traits related to reproductive strategy showing the strongest response. Our findings suggest that urbanisation results in four trait syndromes (mobile generalists, site specialists, central place foragers, and mobile specialists), with resources associated with reproduction and diet likely driving patterns in traits associated with mobility and body size. Functional diversity measures showed varied responses, leading to shifts in trait space likely driven by critical resource distribution and abundance, and taxon-specific trait syndromes. Maximising opportunities to support taxa with different urban trait syndromes should be pivotal in conservation and management programmes within and among cities. This will reduce the likelihood of biotic homogenisation and helps ensure that urban environments have the capacity to respond to future challenges. These actions are critical to reframe the role of cities in global biodiversity loss.info:eu-repo/semantics/publishedVersio

    Coulomb dissociation of N 20,21

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    Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is up to a factor of 5 higher at

    The Psychological Science Accelerator: Advancing Psychology Through a Distributed Collaborative Network

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    Source at https://doi.org/10.1177/2515245918797607.Concerns about the veracity of psychological research have been growing. Many findings in psychological science are based on studies with insufficient statistical power and nonrepresentative samples, or may otherwise be limited to specific, ungeneralizable settings or populations. Crowdsourced research, a type of large-scale collaboration in which one or more research projects are conducted across multiple lab sites, offers a pragmatic solution to these and other current methodological challenges. The Psychological Science Accelerator (PSA) is a distributed network of laboratories designed to enable and support crowdsourced research projects. These projects can focus on novel research questions or replicate prior research in large, diverse samples. The PSA’s mission is to accelerate the accumulation of reliable and generalizable evidence in psychological science. Here, we describe the background, structure, principles, procedures, benefits, and challenges of the PSA. In contrast to other crowdsourced research networks, the PSA is ongoing (as opposed to time limited), efficient (in that structures and principles are reused for different projects), decentralized, diverse (in both subjects and researchers), and inclusive (of proposals, contributions, and other relevant input from anyone inside or outside the network). The PSA and other approaches to crowdsourced psychological science will advance understanding of mental processes and behaviors by enabling rigorous research and systematic examination of its generalizability
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