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Some of the most efficient heuristics for the Euclidean Steiner minimal tree problem in the d-dimensional space, d ≥2, use Delaunay tessellations and minimum spanning trees to determine small subsets of geometrically close terminals. Their low-cost Steiner trees are determined and concatenated in a greedy fashion to obtain a low cost tree spanning all terminals. The weakness of this approach is that obtained solutions are topologically related to minimum spanning trees. To avoid this and to obtain even better solutions, bottleneck distances are utilized to determine good subsets of terminals without being constrained by the topologies of minimum spanning trees. Computational experiments show a significant solution quality improvement.

Some of the most efficient heuristics for the Euclidean Steiner minimal tree problem in the d-dimensional space, d ≥2, use Delaunay tessellations and minimum spanning trees to determine small subsets of geometrically close terminals. Their low-cost Steiner trees are determined and concatenated in a greedy fashion to obtain a low cost tree spanning all terminals. The weakness of this approach is that obtained solutions are topologically related to minimum spanning trees. To avoid this and to obtain even better solutions, bottleneck distances are utilized to determine good subsets of terminals without being constrained by the topologies of minimum spanning trees. Computational experiments show a significant solution quality improvement.

The early life stage is typically a selective bottleneck during which individual performance is important for survival. We investigated size, energetic state, and activity, in relation to recapture probability in the youngest free-swimming stage of a territorial fish, the brown trout. In two experiments, we induced compensatory growth in wild-caught brown trout fry, using a restriction-refeeding protocol. Upon refeeding in the laboratory, the restricted trout showed compensatory growth in mass, but not in length. During this compensatory growth phase, we released the fish into their native stream habitat and then recaptured them after 1 month to assess survival and growth. Despite not having fully compensated body size at release, restricted fish did not show continued growth compensation in the stream, indicating that the natural environment limits growth capacity during early life. Individual baseline activity was scored in open-field tests before and after food restriction and was found repeatable but not significantly affected by growth manipulations. Under natural conditions, we found a positive association between open-field activity and survival (as indicated by recapture probability), but no significant differences between food-restricted and control fish. Initial body length positively influenced survival in the first experiment (early summer), but not in the second (late summer). These results contrast with the assumption that high baseline activity should be riskier in natural environments. For territorial animals, we hypothesize that activity is associated with high aggression and territoriality, which facilitates access to high-quality territories providing both shelter from predation and reduced starvation risk, which reduces mortality risk. Significance statement In the early critical life stage, more active brown trout are better survivors. This finding, which contradicts general assumptions about the balance between predator exposure and food intake, Funding Agencies|Swedish Research Council Formas; Helge Ax: son Johnsons Stiftelse; Wilhelm och Martina Lundgrens Vetenskapsfond; SoWa Research Infrastructure (MEYS CZ grant) [LM2015075]

We study the inefficiency of equilibrium outcomes in bottleneck congestion games. These games model situations in which strategic players compete for a limited number of facilities. Each player allocates his weight to a (feasible) subset of the facilities with the goal to minimize the maximum (weight-dependent) latency that he experiences on any of these facilities. We derive upper and (asymptotically) matching lower bounds on the (strong) price of anarchy of linear bottleneck congestion games for a natural load balancing social cost objective (i.e., minimize the maximum latency of a facility). We restrict our studies to linear latency functions. Linear bottleneck congestion games still constitute a rich class of games and generalize, for example, load balancing games with identical or uniformly related machines with or without restricted assignments.

We study the inefficiency of equilibrium outcomes in bottleneck congestion games. These games model situations in which strategic players compete for a limited number of facilities. Each player allocates his weight to a (feasible) subset of the facilities with the goal to minimize the maximum (weight-dependent) latency that he experiences on any of these facilities. We derive upper and (asymptotically) matching lower bounds on the (strong) price of anarchy of linear bottleneck congestion games for a natural load balancing social cost objective (i.e., minimize the maximum latency of a facility). We restrict our studies to linear latency functions. Linear bottleneck congestion games still constitute a rich class of games and generalize, for example, load balancing games with identical or uniformly related machines with or without restricted assignments.

In the past decade, advances in speed of commodity CPUs have far out-paced advances in memory latency. Main-memory access is therefore increasingly a performance bottleneck for many computer applications, including database systems. In this article, we use a simple scan test to show the severe impact of this bottleneck. The insights gained are translated into guidelines for database architecture; in terms of both data structures and algorithms. We discuss how vertically fragmented data structures optimize cache performance on sequential data access. We then focus on equi-join, typically a random-access operation, and introduce radix algorithms for partitioned hash-join. The performance of these algorithms is quantified using a detailed analytical model that incorporates memory access cost. Experiments that validate this model were performed on the Monet database system. We obtained exact statistics on events like TLB misses, L1 and L2 cache misses, by using hardware performance counters found in modern CPUs. Using our cost model, we show how the carefully tuned memory access pattern of our radix algorithms make them perform well, which is confirmed by experimental results.

In the past decade, advances in speed of commodity CPUs have far out-paced advances in memory latency. Main-memory access is therefore increasingly a performance bottleneck for many computer applications, including database systems. In this article, we use a simple scan test to show the severe impact of this bottleneck. The insights gained are translated into guidelines for database architecture; in terms of both data structures and algorithms. We discuss how vertically fragmented data structures optimize cache performance on sequential data access. We then focus on equi-join, typically a random-access operation, and introduce radix algorithms for partitioned hash-join. The performance of these algorithms is quantified using a detailed analytical model that incorporates memory access cost. Experiments that validate this model were performed on the Monet database system. We obtained exact statistics on events like TLB misses, L1 and L2 cache misses, by using hardware performance counters found in modern CPUs. Using our cost model, we show how the carefully tuned memory access pattern of our radix algorithms make them perform well, which is confirmed by experimental results.

Methylobacterium rhodesianum MB126 growing on fructose accumulates poly(hydroxybutyric acid) (PHB) during exponential growth in contrast to growth on methanol, where the strain accumulates the polyester in response to limitation of several growth factors. A mathematical description of the kinetics, based on the growth-associated term of product formation, yields a good correlation to the experimental data, as it is validated by the course of PHB content after the substrate shift from methanol to fructose. From a comparison of carbon fluxes with enzyme capacities, we assume a bottleneck in the tricarboxylic acid cycle to be the reason for the growth-associated PHB synthesis. PHB formation from fructose, which can be considered as a kind of fermentation, helps overcome the bottleneck. This hypothesis is supported by the fact that the simultaneous PHB synthesis can be suppressed by an additional supply of NADH via the oxidation of formate.

When juvenile mortality or juvenile growth is impacted by temperature and salinity, these factors have a substantial effect on recruitment success and population dynamics in benthic ecosystems. Using freshly settled cyprids of Amphibalanus improvisus, we investigated the combined effects of temperature (12, 20 and 28 °C) and salinity (5, 15 and 30 psu) on early juvenile stage performance. Mortality as well as size (basal diameter, dry weight, and ash-free dry weight) was monitored for a period of 40 days. Mortality was high (42–63 %) during the first week following attachment, regardless of the temperature and salinity treatments. Subsequently, mortality and size were interactively influenced by temperature and salinity. Highest mortality and lowest size of juveniles occurred at lowest temperature (12 °C) and salinity (5 psu). Apparently, low temperature (12 °C) narrowed the barnacles’ salinity tolerance. Juvenile barnacles constructed more shell material compared to body mass at high temperature and high salinity, while a reverse situation was observed at low temperature and low salinity. Our results demonstrate that environmental changes can directly and/or indirectly alter patterns of survivorship and size. Warming and desalination as predicted for the Baltic Sea in the course of climate change may, however, act antagonistically and compensate each other’s isolated effect on barnacles.

When juvenile mortality or juvenile growth is impacted by temperature and salinity, these factors have a substantial effect on recruitment success and population dynamics in benthic ecosystems. Using freshly settled cyprids of Amphibalanus improvisus, we investigated the combined effects of temperature (12, 20 and 28 °C) and salinity (5, 15 and 30 psu) on early juvenile stage performance. Mortality as well as size (basal diameter, dry weight, and ash-free dry weight) was monitored for a period of 40 days. Mortality was high (42–63 %) during the first week following attachment, regardless of the temperature and salinity treatments. Subsequently, mortality and size were interactively influenced by temperature and salinity. Highest mortality and lowest size of juveniles occurred at lowest temperature (12 °C) and salinity (5 psu). Apparently, low temperature (12 °C) narrowed the barnacles’ salinity tolerance. Juvenile barnacles constructed more shell material compared to body mass at high temperature and high salinity, while a reverse situation was observed at low temperature and low salinity. Our results demonstrate that environmental changes can directly and/or indirectly alter patterns of survivorship and size. Warming and desalination as predicted for the Baltic Sea in the course of climate change may, however, act antagonistically and compensate each other’s isolated effect on barnacles.

When juvenile mortality or juvenile growth is impacted by temperature and salinity, these factors have a substantial effect on recruitment success and population dynamics in benthic ecosystems. Using freshly settled cyprids of Amphibalanus improvisus, we investigated the combined effects of temperature (12, 20 and 28 °C) and salinity (5, 15 and 30 psu) on early juvenile stage performance. Mortality as well as size (basal diameter, dry weight, and ash-free dry weight) was monitored for a period of 40 days. Mortality was high (42–63 %) during the first week following attachment, regardless of the temperature and salinity treatments. Subsequently, mortality and size were interactively influenced by temperature and salinity. Highest mortality and lowest size of juveniles occurred at lowest temperature (12 °C) and salinity (5 psu). Apparently, low temperature (12 °C) narrowed the barnacles’ salinity tolerance. Juvenile barnacles constructed more shell material compared to body mass at high temperature and high salinity, while a reverse situation was observed at low temperature and low salinity. Our results demonstrate that environmental changes can directly and/or indirectly alter patterns of survivorship and size. Warming and desalination as predicted for the Baltic Sea in the course of climate change may, however, act antagonistically and compensate each other’s isolated effect on barnacles.

Monitoring query processing has proven to be an effective technique to detect bottlenecks in sequential query execution systems' components. Monitoring distributed execution in parallel systems, however, is a difficult task. The monitoring data of all nodes must be collected at the same time to value load-balancing and scheduling. Furthermore, we want to extract not only information about resource allocation of single processes but also allow for monitoring of single tuples and attribute value distribution. The monitoring system we present in this paper is a client-server architecture where each process of the parallel database system is a client of the monitoring server. This architecture enables the user to monitor even load-balancing or scheduling effects. The monitoring extensions, each client is attached with, provide inspection of the processes at a fine granularity. Furthermore user-defined interpretation of monitoring data on the client side enables emulation of special parallel hardware by low costly components.

Monitoring query processing has proven to be an effective technique to detect bottlenecks in sequential query execution systems' components. Monitoring distributed execution in parallel systems, however, is a difficult task. The monitoring data of all nodes must be collected at the same time to value load-balancing and scheduling. Furthermore, we want to extract not only information about resource allocation of single processes but also allow for monitoring of single tuples and attribute value distribution. The monitoring system we present in this paper is a client-server architecture where each process of the parallel database system is a client of the monitoring server. This architecture enables the user to monitor even load-balancing or scheduling effects. The monitoring extensions, each client is attached with, provide inspection of the processes at a fine granularity. Furthermore user-defined interpretation of monitoring data on the client side enables emulation of special parallel hardware by low costly components.

Despite the global crisis facing migratory benthic fishes, conservation genetic knowledge of these species remains scarce. In this study, we conducted a population genetic analysis using seven microsatellite loci to obtain basic information for determining conservation units and priorities of Cottus hangiongensis in Shiretoko, a mountainous peninsula where sculpin habitats are thought to be in decline throughout the region. The genetic structure was clearly divided between west and east coastal populations, and there was little recent migration between them. The western populations, which are closer to the center of the species' range, had significantly higher genetic diversity than the eastern populations. However, a bottleneck analysis and the inference of demographic history using approximate Bayesian computation showed that only the west group had experienced a significant recent bottleneck, probably due to recent habitat losses. These results suggest that the western and eastern populations should be different conservation units and that the western populations should be prioritized for conservation despite their high genetic diversity. This study contributes to the conservation genetics of diadromous sculpin and reiterates the importance of analyzing not only the current levels but also temporal changes in assessing genetic diversity.

Despite the global crisis facing migratory benthic fishes, conservation genetic knowledge of these species remains scarce. In this study, we conducted a population genetic analysis using seven microsatellite loci to obtain basic information for determining conservation units and priorities of Cottus hangiongensis in Shiretoko, a mountainous peninsula where sculpin habitats are thought to be in decline throughout the region. The genetic structure was clearly divided between west and east coastal populations, and there was little recent migration between them. The western populations, which are closer to the center of the species' range, had significantly higher genetic diversity than the eastern populations. However, a bottleneck analysis and the inference of demographic history using approximate Bayesian computation showed that only the west group had experienced a significant recent bottleneck, probably due to recent habitat losses. These results suggest that the western and eastern populations should be different conservation units and that the western populations should be prioritized for conservation despite their high genetic diversity. This study contributes to the conservation genetics of diadromous sculpin and reiterates the importance of analyzing not only the current levels but also temporal changes in assessing genetic diversity.

The cross section of the 89Y(n, ¿) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N = 50 and a consequent small neutron capture cross section, 89Y represents one of the key nuclides for the stellar s-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and main s-process components take place. 89Y, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were performed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a comparison with results reported in the literature shows differences in resonance parameters, the present data are consistent with the Maxwellian averaged cross section suggested by the astrophysical database KADoNiS., This research was funded by the European Community Seventh Framework Programme FP7/2007- 2011 under the Project CHANDA (Grant No. 605203), by the European Commission within HORIZON2020 via the EURATOM project EUFRAT for transnational access and by the funding agencies of the participating institutes., Article signat per 135 autors/es: G. Tagliente, P.M. Milazzo, C. Paradela, S. Kopecky, D. Vescovi, G. Alaerts, L.A. Damone, J. Heyse, M. Krtiˇcka, P. Schillebeeckx, A. Mengoni, R. Wynants, S. Valenta, O. Aberle, V. Alcayne, S.Amaducci, J. Andrzejewski, L. Audouin, V. Babiano-Suarez, M. Bacak, M. Barbagallo, V. Bécares, F. Beˇcváˇr, G. Bellia, E. Berthoumieux, J. Billowes, D. Bosnar, A.S. Brown, M. Busso, M. Caamaño, L. Caballero, M. Calviani, F. Calviño, D. Cano-Ott, A. Casanovas, F. Cerutti, Y.H. Chen, E. Chiaveri, N. Colonna, G.P. Cortés, M.A. Cortés-Giraldo, L. Cosentino, S. Cristallo, M. Diakaki, M. Dietz, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, Z. Eleme, B. Fernández-Domíngez, A.Ferrari, I. Ferro-Gonçalves, P. Finocchiaro, V. Furman, R. Garg, A. Gawlik, S. Gilardoni, T. Glodariu, K. Göbel32 , E. González-Romero, C. Guerrero, F. Gunsing, S. Heinitz, D.G. Jenkins, E. Jericha, Y. Kadi , F. Käppeler, A. Kimura, N. Kivel, M. Kokkoris, Y. Kopatch, D. Kurtulgil, I. Ladarescu, A.C. Larsen, C. Lederer-Woods, J. Lerendegui-Marco, S. Lo Meo, S.J. Lonsdale, M. Lugaro, D. Macina, A. Manna, T. Martínez, A. Masi, C. Massimi, P.F. Mastinu, M. Mastromarco, F. Matteucci, E. Maugeri, A. Mazzone, E. Mendoza, V. Michalopoulou, F. Mingrone, A. Musumarra, A. Negret, R. Nolte, F. Ogállar, A. Oprea, N. Patronis, A. Pavlik, J. Perkowski, L. Piersanti, I. Porras, J. Praena, J.M. Quesada, D. Radeck, D. Ramos Doval, R. Reifarth, D. Rochman, C. Rubbia, M. Sabaté-Gilarte, A. Saxena, D. Schumann, A.G. Smith, M. Spelta, N. Sosnin, A. Stamatopoulos, J.L. Tain, Z. Talip, A.E. Tarifeño-Saldivia, L. Tassan-Got, P. Torres-Sánchez, A. Tsinganis, J. Ulrich, S. Urlass, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, P.J. Woods, T.J. Wright, P. Zugec, Postprint (author's final draft)

Spotters (also denoted as switchers) are specialized terminal tractors, which are dedicated to the rapid maneuvering of semitrailers between parking lot and dock doors in large trailer yards. This paper is dedicated to spotter scheduling, i.e., the assignment of predefined trailer movements to a given fleet of spotters. The limited number of dock doors for loading and unloading is often the scarce resource during trailer processing, so that idle time of the bottleneck, e.g., caused by unforeseen delay in the yard, is to be avoided. In this setting, we aim to insert time buffers between any pair of subsequent jobs assigned to the same spotter, so that small delays are not propagated and subsequent jobs can still be executed in a timely manner. We formalize two versions of the resulting robust spotter scheduling problem and provide efficient algorithms for finding optimal solutions in polynomial time. Furthermore, we simulate delays during the execution of spotter schedules and show that the right robustness objective can greatly improve yard performance.

Spotters (also denoted as switchers) are specialized terminal tractors, which are dedicated to the rapid maneuvering of semitrailers between parking lot and dock doors in large trailer yards. This paper is dedicated to spotter scheduling, i.e., the assignment of predefined trailer movements to a given fleet of spotters. The limited number of dock doors for loading and unloading is often the scarce resource during trailer processing, so that idle time of the bottleneck, e.g., caused by unforeseen delay in the yard, is to be avoided. In this setting, we aim to insert time buffers between any pair of subsequent jobs assigned to the same spotter, so that small delays are not propagated and subsequent jobs can still be executed in a timely manner. We formalize two versions of the resulting robust spotter scheduling problem and provide efficient algorithms for finding optimal solutions in polynomial time. Furthermore, we simulate delays during the execution of spotter schedules and show that the right robustness objective can greatly improve yard performance.

Spotters (also denoted as switchers) are specialized terminal tractors, which are dedicated to the rapid maneuvering of semitrailers between parking lot and dock doors in large trailer yards. This paper is dedicated to spotter scheduling, i.e., the assignment of predefined trailer movements to a given fleet of spotters. The limited number of dock doors for loading and unloading is often the scarce resource during trailer processing, so that idle time of the bottleneck, e.g., caused by unforeseen delay in the yard, is to be avoided. In this setting, we aim to insert time buffers between any pair of subsequent jobs assigned to the same spotter, so that small delays are not propagated and subsequent jobs can still be executed in a timely manner. We formalize two versions of the resulting robust spotter scheduling problem and provide efficient algorithms for finding optimal solutions in polynomial time. Furthermore, we simulate delays during the execution of spotter schedules and show that the right robustness objective can greatly improve yard performance.

We consider the effects of inspection and repair stations on the production capacity and product quality in a serial garments production line with possible inspection and repair following each operation. We construct a profit function that takes into account inspection, repair, scrap, and goodwill costs, as well as the capacity of each station. Then we discuss how the profit function can be maximized and provide properties of the optimal inspection plan. Our analysis captures the possibility of increasing production capacity by scrapping or repairing defective items before a bottleneck operation station, and hence reducing the waste of operation capacity on defective products. Our numerical results show that incorporating such capacity considerations can have substantial impact on the optimal inspection policy and that optimal inspection allocations can be identified quickly even for large problem instances.

We consider the effects of inspection and repair stations on the production capacity and product quality in a serial garments production line with possible inspection and repair following each operation. We construct a profit function that takes into account inspection, repair, scrap, and goodwill costs, as well as the capacity of each station. Then we discuss how the profit function can be maximized and provide properties of the optimal inspection plan. Our analysis captures the possibility of increasing production capacity by scrapping or repairing defective items before a bottleneck operation station, and hence reducing the waste of operation capacity on defective products. Our numerical results show that incorporating such capacity considerations can have substantial impact on the optimal inspection policy and that optimal inspection allocations can be identified quickly even for large problem instances.

Convolutional neural networks (CNN) are known to learn an image representation that captures concepts relevant to the task, but do so in an implicit way that hampers model interpretability. However, one could argue that such a representation is hidden in the neurons and can be made explicit by teaching the model to recognize semantically interpretable attributes that are present in the scene. We call such an intermediate layer a semantic bottleneck. Once the attributes are learned, they can be re-combined to reach the final decision and provide both an accurate prediction and an explicit reasoning behind the CNN decision. In this paper, we look into semantic bottlenecks that capture context: we want attributes to be in groups of a few meaningful elements and participate jointly to the final decision. We use a two-layer semantic bottleneck that gathers attributes into interpretable, sparse groups, allowing them contribute differently to the final output depending on the context. We test our contextual semantic interpretable bottleneck (CSIB) on the task of landscape scenicness estimation and train the semantic interpretable bottleneck using an auxiliary database (SUN Attributes). Our model yields in predictions as accurate as a non-interpretable baseline when applied to a real-world test set of Flickr images, all while providing clear and interpretable explanations for each prediction.

Migration monitoring may allow us to detect population trends over large geographic areas because the pattern of change in migrant counts may be expected to follow the pattern of change in population size. We analysed recent regional European population trends of migratory soaring birds from rates of change in migration counts over the Strait of Gibraltar (Spain) during the years (1999–2013). An additional bottleneck (Organbidexka, France) within the same migratory route and period was also considered. We estimated count trends by fitting a log-generalized linear model to the time series of each species counts. The counts in Organbidexka were used to test the consistency in the observed trends over the Strait of Gibraltar. Migration counts of White and Black Storks, Black Kites, Short-toed and Booted Eagles as well as Egyptian Vultures showed a linear increase over the Strait of Gibraltar throughout the 15-year period. In contrast, Honey Buzzard numbers remained stable. Trends were highly consistent with those recorded in Organbidexka. We suggest that the larger slopes for the trends in Organbidexka when compared with the Strait reflect an increasing tendency in these species to overwinter in southern Europe. A combination of complementary data sets collected at different bottleneck sites within the European–African flyway system may become a fundamental tool for the investigation of migratory patterns and population trends and changes of soaring migrant birds all over Europe.https://doi.org/10.1007/s10531-016-1047-4

The partial evaluation and assembly framework has recently been applied for processing subgraph matching queries over large-scale knowledge graphs in the distributed environment. The framework is implemented on the master-slave architecture, endowed with outstanding scalability. However, there are two drawbacks of partial evaluation: if the volume of intermediate results is large, a large number of repeated partial matches will be generated; and the assembly computation handled by the master would be a bottleneck. In this paper, we propose an optimal partial evaluation algorithm and a filter method to reduce partial matches by exploring the computing characteristics of partial evaluation and assembly framework. (1) An index structure named inner boundary node index (IBN-Index) is constructed to prune for graph exploration to improve the searching efficiency of the partial evaluation phase. (2) The boundary characteristics of local partial matches are utilized to construct a boundary node index (BN-Index) to reduce the number of local partial matches. (3) The experimental results over benchmark datasets show that our approach outperforms the state-of-the-art methods.

Studies about diversification of Neotropical open-habitat organisms are scarce, especially in frogs, in which almost all studied species from Cerrado, Chaco, and Caatinga are mainly associated with gallery forest. Here we tested hypotheses about diversification in Neotropical open habitats (savannas and grasslands) using as model a small treefrog associated with these environments and widely distributed throughout South America. We sampled 68 individuals from 43 localities throughout the geographic distribution of Scinax fuscomarginatus and used one mitochondrial and three nuclear DNA markers to define genetic clusters. Based on population assignments and previously proposed diversification hypotheses for the Cerrado, we designed different models to be tested by approximate Bayesian computation (ABC). We found four genetic clusters which reflect the current distribution of open habitats of the Central Brazilian plateau and of the Cerrado lowlands. Among the models tested with ABC, the best-supported model was a scenario of multiple refugia in which all populations experienced population size reduction (bottleneck) in a relatively recent time, with the most ancient split event surrounding the Last Interglacial (LIG). During interglacial periods, warmer and wetter climate would have favored the geographic expansion of forests, resulting in the retraction and fragmentation of open habitats like savannas and grasslands. Populations of species associated with open habitats, including S. fuscomarginatus, would have remained isolated in relatively small stable areas with reduced gene flow among them.

Studies about diversification of Neotropical open-habitat organisms are scarce, especially in frogs, in which almost all studied species from Cerrado, Chaco, and Caatinga are mainly associated with gallery forest. Here we tested hypotheses about diversification in Neotropical open habitats (savannas and grasslands) using as model a small treefrog associated with these environments and widely distributed throughout South America. We sampled 68 individuals from 43 localities throughout the geographic distribution of Scinax fuscomarginatus and used one mitochondrial and three nuclear DNA markers to define genetic clusters. Based on population assignments and previously proposed diversification hypotheses for the Cerrado, we designed different models to be tested by approximate Bayesian computation (ABC). We found four genetic clusters which reflect the current distribution of open habitats of the Central Brazilian plateau and of the Cerrado lowlands. Among the models tested with ABC, the best-supported model was a scenario of multiple refugia in which all populations experienced population size reduction (bottleneck) in a relatively recent time, with the most ancient split event surrounding the Last Interglacial (LIG). During interglacial periods, warmer and wetter climate would have favored the geographic expansion of forests, resulting in the retraction and fragmentation of open habitats like savannas and grasslands. Populations of species associated with open habitats, including S. fuscomarginatus, would have remained isolated in relatively small stable areas with reduced gene flow among them.

Modern agriculture provides us with an abundance of cheap and high-quality food but it also has a large negative impact on the environment. It is clear that agriculture must become more sustainable, even more so in the face of climate change. Precision agriculture is one of the pathways to a more sustainable agriculture. A precision agriculture application consists of three parts: data, models, and actuators. First, data are collected about crops, soils, and livestock. Then models are used to transform data into agronomic advice. Finally, recommendations lead to actuation in the field. All three elements must be implemented properly: a chain is only as strong as its weakest link. Access to data is a major obstacle for the application of model-based technologies in precision agriculture. Models are available but a critical and improved understanding of what we need and can obtain from the model is in many cases still needed. Actuation is not the biggest bottleneck. Overall, there is a need for better connections between researchers, extension workers, farmers, and advisors to leverage the benefits of data and modelling.

This chapter works on presenting a background overview associated with vehicular communications and networking. The first part focuses on reviewing the recent advancements and progress booming in vehicular networking and standardization. As existing wireless solutions cannot guarantee safe, swift, and ubiquitous high-volume data transfer in future vehicular-to-everything communication, mmWave comes into play to help address the information bottleneck beyond the 5G era. Henceforth, the second part follows to provide a holistic overview of mmWave physical fundamentals and mmWave system properties. The chapter is concluded with a brief organization of this monograph studying mmWave vehicular communications. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Landraces of maize (Zea mays L.) have a variability not found in the elite hybrids due to the bottleneck during selection. There is a renewed interest in using that variability, incorporating alleles for specific traits, or widening the general variability of elite germplasm. In Europe, there is also an interest in the direct use of local landraces by farmer’s associations seeking agriculture that preserves crop diversity. Pre-breeding programs are aimed to reduce the yield gap among landraces and improved materials. In the Misión Biológica de Galicia we have carried out three cycles of a S recurrent selection program for yield on four local landraces from Northwestern Spain with the objective of obtaining improved populations that might be cultivated by farmers and that could be used as sources of superior inbred lines. One hundred plants were selfed in each landrace and the S families were evaluated in a 10 × 10 simple lattice. The 20 S families with the highest grain yields were randomly intercrossed to form the selected population of each landrace. After three cycles of selection, each population and its cycles of selection were evaluated in three locations for two years. All the populations had a consistent yield gain in the first cycle of selection. However, the response in later cycles differed among the populations: one population had a continuous increase of 21% per cycle while two populations had a reduced yield in the last cycles. Our results highlight the need to include secondary traits to avoid unintentional indirect effects. We conclude that, in pre-breeding programs, it could be worthy to use large effective numbers to prevent inbreeding depression, particularly when the objective is the direct use of improved landraces. Another conclusion is that recurrent selection does not seem to be as efficient on European germplasm as it is on Corn Belt varieties. Finally, obtaining valuable new germplasm requires a sustained, long-term effort.

Populations at the far edges of their ranges tend to be scarce, and they are frequently of conservation concern. This paper examines the distribution of three raptors (Circaetus gallicus, Hieraaetus pennatus and Milvus migrans) at the southwestern boundary of their breeding range. We modelled species distribution to obtain habitat suitability indexes that were validated with extensive fieldwork in Morocco and Spain. Our results support a strong effect of habitat suitability and a bottleneck effect of the Strait of Gibraltar on raptor distribution. However, after controlling for these effects, the three species were scarcer in Morocco than in Spain. We did not find differences between the two countries in the number of power lines that are dangerous to raptors or in general impacts of agricultural intensification on bird populations (we assessed more farmland birds in Morocco). However, many more people (i.e., shepherds) were detected in Morocco, whose negative effect on raptors could explain the depletion of their populations. These transboundary differences are used to discuss the fate of these peripheral populations in a context of climate change and rural abandonment. They also highlight the need for strengthening raptor conservation around the Strait of Gibraltar, where a permanent flow of raptors converges throughout the year., Ministerio de Economía y Competitividad (MINECO), Universidad Complutense de Madrid, Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Predation is just one of several possible causal factors of the red-legged partridge decline. It is a key factor affecting the success of red-legged partridge nests, but agricultural activities can be the main cause of nest loss in some areas. Because hatchlings are more vulnerable to predation, this stage represents a critical bottleneck for partridge populations. Most restocking programmes fail due to predation due to the partridges’ inability to adapt to the new situation. Although predator control is a widespread game management practice for the red-legged partridge it has limited effects in most management situations. Some measures indirectly affecting the effects of predation, such as habitat management, could represent a long-lasting measure for reducing partridge predation preferable over traditional predator control, and they could revert current negative trends.

Bipartite graphs are of great importance in many real-world applications. Butterfly, which is a complete 2 × 2 biclique, plays a key role in bipartite graphs. In this paper, we investigate the problem of efficient counting the number of butterflies. The most advanced techniques are based on enumerating wedges which is the dominant cost of counting butterflies. Nevertheless, the existing algorithms cannot efficiently handle large-scale bipartite graphs. This becomes a bottleneck in large-scale applications. In this paper, instead of the existing layer-priority-based techniques, we propose a vertex-priority-based paradigm BFC-VP to enumerate much fewer wedges; this leads to a significant improvement of the time complexity of the state-of-the-art algorithms. In addition, we present cache-aware strategies to further improve the time efficiency while theoretically retaining the time complexity of BFC-VP. We also show that our proposed techniques can work efficiently in external and parallel contexts. Moreover, we study the butterfly counting problem on batch-dynamic graphs. Specifically, given a bipartite graph G and a batch-update of edges B, we aim to maintain the number of butterflies in G. To tackle this problem, fast vertex-priority-based algorithms are proposed with optimizations for reducing the computation of existing wedges in G. Our extensive empirical studies demonstrate that the proposed techniques significantly outperform the baseline solutions on real datasets.

Producción Científica, Data centers are a fundamental infrastructure in the Big-Data era, where applications and services demand a high amount of data and minimum response times. The interconnection network is an essential subsystem in the data center, as it must guarantee high communication bandwidth and low latency to the communication operations of applications, otherwise becoming the system bottleneck. Simulation is widely used to model the network functionality and to evaluate its performance under specific workloads. Apart from the network modeling, it is essential to characterize the end-nodes communication pattern, which will help identify bottlenecks and flaws in the network architecture. In previous works, we proposed the VEF traces framework: a set of tools to capture communication traffic of MPI-based applications and generate traffic traces used to feed network simulator tools. In this paper, we extend the VEF traces framework with new communication workloads such as deep-learning training applications and online data-intensive workloads., Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación (MCIN/AEI/10.13039/501100011033) R &D Project Grant (PID2019-109001RA-I00), Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE

Producción Científica, Data centers are a fundamental infrastructure in the Big-Data era, where applications and services demand a high amount of data and minimum response times. The interconnection network is an essential subsystem in the data center, as it must guarantee high communication bandwidth and low latency to the communication operations of applications, otherwise becoming the system bottleneck. Simulation is widely used to model the network functionality and to evaluate its performance under specific workloads. Apart from the network modeling, it is essential to characterize the end-nodes communication pattern, which will help identify bottlenecks and flaws in the network architecture. In previous works, we proposed the VEF traces framework: a set of tools to capture communication traffic of MPI-based applications and generate traffic traces used to feed network simulator tools. In this paper, we extend the VEF traces framework with new communication workloads such as deep-learning training applications and online data-intensive workloads., Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación (MCIN/AEI/10.13039/501100011033) R &D Project Grant (PID2019-109001RA-I00), Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE

Making a consistency with the objectives of circular economy, herein, waste pistachios shells were utilized for the development of hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) electrocatalysts which are the key bottleneck in the technological evolution of electrolyzers and fuel cells, respectively. As an alternative to scarce and expensive platinum-group-metal (PGM) electrocatalysts, metal nitrogen carbons (MNCs) are emerging as a promising candidate for both aforementioned electrocatalysis where iron and nickel are the metal of choice for ORR and HER, respectively. Therefore, FeNCs and NiNCs were fabricated utilizing inedible pistachio shells as a low-cost biosource of carbon. The steps involved in the fabrication of electrocatalyst were correlated with electrochemical performance in alkaline media. Encouraging onset potential of ~ 0.88 V vs RHE with a possibility of a 2 + 2 reaction pathway was observed in pyrolyzed and ball-milled FeNC. However, HF etching for template removal slightly affected the kinetics and eventually resulted in a relatively higher yield of peroxide. In parallel, the pyrolyzed NiNC demonstrated a lower HER overpotential of ~ 0.4 V vs RHE at − 10 mA cm−2. Nevertheless, acid washing adversely affected the HER performance and consequently, very high overpotential was witnessed.

The verifiable encryption of bits is the main computational step that is needed to prepare ballots in many practical voting protocols. Its computational load can also be a practical bottleneck, preventing the deployment of some protocols or requiring the use of computing clusters. We investigate the question of producing many verifiably encrypted bits in an efficient and portable way, using as a baseline the protocol that is in use in essentially all modern voting systems and libraries supporting homomorphic voting, including ElectionGuard, a state-of-the- art open source voting SDK deployed in government elections. Combining fixed base exponentiation techniques and new encryption and ZK proof mechanisms, we obtain speed-ups by more than one order of magnitude against standard implementations. Our exploration requires balancing conflicting optimization strategies, and the use of asymptotically less efficient protocols that turn out to be very effective in practice. Several of our proposed improvements are now on the ElectionGuard roadmap.

Producción Científica, Data centers are a fundamental infrastructure in the Big-Data era, where applications and services demand a high amount of data and minimum response times. The interconnection network is an essential subsystem in the data center, as it must guarantee high communication bandwidth and low latency to the communication operations of applications, otherwise becoming the system bottleneck. Simulation is widely used to model the network functionality and to evaluate its performance under specific workloads. Apart from the network modeling, it is essential to characterize the end-nodes communication pattern, which will help identify bottlenecks and flaws in the network architecture. In previous works, we proposed the VEF traces framework: a set of tools to capture communication traffic of MPI-based applications and generate traffic traces used to feed network simulator tools. In this paper, we extend the VEF traces framework with new communication workloads such as deep-learning training applications and online data-intensive workloads., Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación (MCIN/AEI/10.13039/501100011033) R &D Project Grant (PID2019-109001RA-I00), Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE

In situ visualization on high-performance computing systems allows us to analyze simulation results that would otherwise be impossible, given the size of the simulation data sets and offline post-processing execution time. We develop an in situ adaptor for Paraview Catalyst and Nek5000, a massively parallel Fortran and C code for computational fluid dynamics. We perform a strong scalability test up to 2048 cores on KTH’s Beskow Cray XC40 supercomputer and assess in situ visualization’s impact on the Nek5000 performance. In our study case, a high-fidelity simulation of turbulent flow, we observe that in situ operations significantly limit the strong scalability of the code, reducing the relative parallel efficiency to only ≈ 21 % on 2048 cores (the relative efficiency of Nek5000 without in situ operations is ≈ 99 %). Through profiling with Arm MAP, we identified a bottleneck in the image composition step (that uses the Radix-kr algorithm) where a majority of the time is spent on MPI communication. We also identified an imbalance of in situ processing time between rank 0 and all other ranks. In our case, better scaling and load-balancing in the parallel image composition would considerably improve the performance of Nek5000 with in situ capabilities. In general, the result of this study highlights the technical challenges posed by the integration of high-performance simulation codes and data-analysis libraries and their practical use in complex cases, even when efficient algorithms already exist for a certain application scenario., QC 20220502

Producción Científica, Data centers are a fundamental infrastructure in the Big-Data era, where applications and services demand a high amount of data and minimum response times. The interconnection network is an essential subsystem in the data center, as it must guarantee high communication bandwidth and low latency to the communication operations of applications, otherwise becoming the system bottleneck. Simulation is widely used to model the network functionality and to evaluate its performance under specific workloads. Apart from the network modeling, it is essential to characterize the end-nodes communication pattern, which will help identify bottlenecks and flaws in the network architecture. In previous works, we proposed the VEF traces framework: a set of tools to capture communication traffic of MPI-based applications and generate traffic traces used to feed network simulator tools. In this paper, we extend the VEF traces framework with new communication workloads such as deep-learning training applications and online data-intensive workloads., Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación (MCIN/AEI/10.13039/501100011033) R &D Project Grant (PID2019-109001RA-I00), Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCLE

Facing the challenges of our environmental crisis, the AEC sector must significantly lower its carbon footprint and use of first-use resources. A specific target is the reduction of the amount of concrete used. Funicular structures that base their strength on their structurally-informed geometry allow for material efficiency. However, a bottleneck for their construction lies in their costly and wasteful formworks and complex reinforcement placement., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Applied Mechanics

The level of habitat availability influences genetic divergence among populations and the genetic diversity within populations. In the marine environment, near-shore species are among the most sensitive to habitat changes. Knowledge of how historical environmental change affected habitat availability and genetic variation can be applied to the development of proactive management strategies of exploited species. Here, we modeled the contemporary and historical distribution of Lutjanus jocu in Brazil. We describe patterns of genomic diversity to better understand how climatic cycles might correlate with the species demographic history and current genetic structure. We show that during the Last Glacial Maximum, there were ecological barriers that are absent today, possibly dividing the range of the species into three geographically separated areas of suitable habitat. Consistent with a historical reduction in habitat area, our analysis of demographic changes shows that L. jocu experienced a severe bottleneck followed by a population size expansion. We also found an absence of genetic structure and similar levels of genetic diversity throughout the sampled range of the species. Collectively, our results suggest that habitat availability changes have not obviously influenced contemporary levels of genetic divergence between populations. However, our demographic analyses suggest that the high sensitivity of this species to environmental change should be taken into consideration for management strategies. Furthermore, the general low levels of genetic structure and inference of high gene flow suggest that L. jocu likely constitutes a single stock in Brazilian waters and, therefore, requires coordinated legislation and management across its distribution.

This work addresses visual cross-view metric localization for outdoor robotics. Given a ground-level color image and a satellite patch that contains the local surroundings, the task is to identify the location of the ground camera within the satellite patch. Related work addressed this task for range-sensors (LiDAR, Radar), but for vision, only as a secondary regression step after an initial cross-view image retrieval step. Since the local satellite patch could also be retrieved through any rough localization prior (e.g. from GPS/GNSS, temporal filtering), we drop the image retrieval objective and focus on the metric localization only. We devise a novel network architecture with denser satellite descriptors, similarity matching at the bottleneck (rather than at the output as in image retrieval), and a dense spatial distribution as output to capture multi-modal localization ambiguities. We compare against a state-of-the-art regression baseline that uses global image descriptors. Quantitative and qualitative experimental results on the recently proposed VIGOR and the Oxford RobotCar datasets validate our design. The produced probabilities are correlated with localization accuracy, and can even be used to roughly estimate the ground camera’s heading when its orientation is unknown. Overall, our method reduces the median metric localization error by 51%, 37%, and 28% compared to the state-of-the-art when generalizing respectively in the same area, across areas, and across time., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Intelligent Vehicles

Bipartite graphs are of great importance in many real-world applications. Butterfly, which is a complete 2 × 2 biclique, plays a key role in bipartite graphs. In this paper, we investigate the problem of efficient counting the number of butterflies. The most advanced techniques are based on enumerating wedges which is the dominant cost of counting butterflies. Nevertheless, the existing algorithms cannot efficiently handle large-scale bipartite graphs. This becomes a bottleneck in large-scale applications. In this paper, instead of the existing layer-priority-based techniques, we propose a vertex-priority-based paradigm BFC-VP to enumerate much fewer wedges; this leads to a significant improvement of the time complexity of the state-of-the-art algorithms. In addition, we present cache-aware strategies to further improve the time efficiency while theoretically retaining the time complexity of BFC-VP. We also show that our proposed techniques can work efficiently in external and parallel contexts. Moreover, we study the butterfly counting problem on batch-dynamic graphs. Specifically, given a bipartite graph G and a batch-update of edges B, we aim to maintain the number of butterflies in G. To tackle this problem, fast vertex-priority-based algorithms are proposed with optimizations for reducing the computation of existing wedges in G. Our extensive empirical studies demonstrate that the proposed techniques significantly outperform the baseline solutions on real datasets.