pinecone/core-2020-05-10-deduplication huggingface dataset:
On Linear Configurations in Subsets of Compact Abelian Groups, and Invariant Measurable Hypergraphs

We prove an arithmetic removal result for all compact abelian groups, generalizing a finitary removal result of Král’, Serra, and the third author. To this end, we consider infinite measurable hypergraphs that are invariant under certain group actions, and for these hypergraphs we prove a symmetry-preserving removal lemma, which extends a finitary result of the same name by the second author. We deduce our arithmetic removal result by applying this lemma to a specific type of invariant measurable hypergraph. As a direct consequence of our removal result, we obtain the following generalization of Szemerédi’s theorem: for any compact abelian group G, any measurable set A⊆ G with Haar probability μ(A) ≥ α> 0 satisfies ∫G∫G1A(x)1A(x+r)..1A(x+(k-1)r)dμ(x)dμ(r)≥c, where the constant c= c(α, k) > 0 is valid uniformly for all G. This result is shown to hold more generally for any translationinvariant system of r linear equations given by an integer matrix with coprime r× r minors. © 2016, Springer International Publishing
Comparing and simplifying distinct-cluster phylogenetic networks

Phylogenetic networks are rooted acyclic directed graphs in which the leaves
are identified with members of a set X of species. The cluster of a vertex is
the set of leaves that are descendants of the vertex. A network is
"distinct-cluster" if distinct vertices have distinct clusters. This paper
focuses on the set DC(X) of distinct-cluster networks whose leaves are
identified with the members of X. For a fixed X, a metric on DC(X) is defined.
There is a "cluster-preserving" simplification process by which vertices or
certain arcs may be removed without changing the clusters of any remaining
vertices. Many of the resulting networks may be uniquely determined without
regard to the order of the simplifying operations.Comment: This is version 2. A previous version is already on ArXi
Analysis of Bidirectional Ballot Sequences and Random Walks Ending in
  their Maximum

Consider non-negative lattice paths ending at their maximum height, which
will be called admissible paths. We show that the probability for a lattice
path to be admissible is related to the Chebyshev polynomials of the first or
second kind, depending on whether the lattice path is defined with a reflective
barrier or not. Parameters like the number of admissible paths with given
length or the expected height are analyzed asymptotically. Additionally, we use
a bijection between admissible random walks and special binary sequences to
prove a recent conjecture by Zhao on ballot sequences
Generalized Polarization Modules

This work enrols the research line of M. Haiman on the Operator Theorem (the
old operator conjecture). This theorem states that the smallest
$\mathfrak{S}_n$-module closed under taking partial derivatives and closed
under the action of polarization operators that contains the Vandermonde
determinant is the space of diagonal harmonics polynomials. We start
generalizing the context of this theorem to the context of polynomials in
$\ell$ sets of $n$ variables $x_{ij}$ with $1\leq i\leq \ell$ et $1\leq j\leq
n$. Given a $\mathfrak{S}_n$-stable family of homogeneous polynomials in the
variables $x_{ij}$ the smallest vector space closed under taking partial
derivatives and closed under the action of polarization operators that contains
$F$ is the polarization module generated by the family $F$. These polarization
modules are all representation of the direct product
$\mathfrak{S}_n\times{GL}_{\ell}(\mathbb{C})$. In order to study the
decomposition into irreducible submodules, we compute the graded Frobenius
characteristic of these modules. For several cases of $\mathfrak{S}_n$-stable
families of homogeneous polynomials in $n$ variables, for every $n\geq 1$, we
show general formulas for this graded characteristic in a global manner,
independent of the value of $\ell$.Comment: This is a full version of the Extended Abstract arXiv:1411.4197
  [math.CO
Ehrhart series of fractional stable set polytopes of finite graphs

The fractional stable set polytope ${\rm FRAC}(G)$ of a simple graph $G$ with
$d$ vertices is a rational polytope that is the set of nonnegative vectors
$(x_1,\ldots,x_d)$ satisfying $x_i+x_j\le 1$ for every edge $(i,j)$ of $G$. In
this paper we show that (i) The $\delta$-vector of a lattice polytope $2 {\rm
FRAC}(G)$ is alternatingly increasing; (ii) The Ehrhart ring of ${\rm FRAC}(G)$
is Gorenstein; (iii) The coefficients of the numerator of the Ehrhart series of
${\rm FRAC}(G)$ are symmetric, unimodal and computed by the $\delta$-vector of
$2 {\rm FRAC}(G)$.Comment: 12 pages, V2: some minor revisions, references adde
Once punctured disks, non-convex polygons, and pointihedra

We explore several families of flip-graphs, all related to polygons or
punctured polygons. In particular, we consider the topological flip-graphs of
once-punctured polygons which, in turn, contain all possible geometric
flip-graphs of polygons with a marked point as embedded sub-graphs. Our main
focus is on the geometric properties of these graphs and how they relate to one
another. In particular, we show that the embeddings between them are strongly
convex (or, said otherwise, totally geodesic). We also find bounds on the
diameters of these graphs, sometimes using the strongly convex embeddings.
Finally, we show how these graphs relate to different polytopes, namely type D
associahedra and a family of secondary polytopes which we call pointihedra.Comment: 24 pages, 6 figure
Physical characteristics of Acidic Mining Lake 111

Measurements of physical properties have been conducted in Mining Lake 111 (ML111), located in Lusatia, Germany over the time period 1996- 2002. In the deepest area of the ML111, a monimolimnion was observed, that persisted for the years 1996-1999. It disappeared in 2000 and again formed in 2001. The definition of the main physical properties, such as the temperature compensation for electrical conductivity, in acidic mining lakes required a lake specific approach. The relation between conductivity, temperature and density was determined for the acidic ML111. The variation in dissolved substances affected these relationships such that conductivity varied with temperature even in different layers of the water column and the limitations for a lake wide correlation was evident. Variation in the conductivity of the epilimnion could be verified, and agreed with the estimates of evaporation from the lake surface during summer stratification. Calculations, following the gradient flux method, indicated vertical transport coefficients between 10-7 and 10-6m2/s throughout the hypolimnion. The heat budget indicated that heat was transferred into the lake bed or the ground during spring
Seasonal variability of surface fCO2 in the Strait of Gibraltar

10 páginas, 6 figuras.-- The final publication is\ud
available at www.springerlink.comFrom September 2005 to May 2006 four\ud
cruises were performed in the Strait of Gibraltar to\ud
study the seasonal variability of carbon dioxide surface\ud
waters and assess the air-sea CO2 fluxes. Continuous\ud
water measurement of fugacity ofCO2 (fCO2),\ud
temperature and salinity was performed along the\ud
longitudinal and latitudinal axes of the Strait. Additionally,\ud
discrete surface water samples were taken to\ud
measure dissolved inorganic carbon (DIC) and oxygen.\ud
The spatial distribution of surface fCO2 showed low variability compared to the seasonal scale, with\ud
fCO2 values ranging from 329 matm in March to 387\ud
matm in September. Seasonal variability of fCO2 was\ud
assessed and discussed in terms of temperature and\ud
biology, and the temperature was the main controlling\ud
factor. The Strait of Gibraltar is CO2 undersaturated\ud
most of the year, except in September, when the\ud
annual average CO2 uptake equals 0.28 mol C m 2\ud
yr 1, if behaves as a discreet sink of CO2 on an annual\ud
scaleThis work has\ud
been supported by the Spanish CICYT under the\ud
contract CTM2005-01364/MAR and by the European\ud
CARBOOCEAN IP (511176 GOCE)Peer reviewe
Implications of biological and physical diversity for resilience and resistance patterns within Highly Dynamic River Systems

The structure and function of alluvial Highly Dynamic River Systems (HDRS) are driven by highly variable hydrological disturbance regimes, and alternate between resistant, metastable states and resilient, transitional states. These are in turn subject to influences of feedback loops within hydrogeomorphic and biological processes. Here we consider how resistance and resilience largely determine HDRS ecosystem trajectories and how these characteristics can be modified by natural and anthropogenic processes. We review the mechanisms by which biodiversity can affect both resistance and resilience and introduce a conceptual framework that incorporates some unique HDRS characteristics. We suggest that resilient and resistant patterns frequently coexist in the active tract of these river systems, and that this coexistance promotes the return of metastable states after major disturbances. In contrast, highly resistant and poorly resilient patterns dominate at their external boundaries. The loss of these natural dynamics resulting from direct and indirect human impacts causes deviations to resistance and resilience patterns and therefore to HDRS trajectory. We propose that understanding the role of interactions between biological and physical processes that control resistance and resilience is crucial for system restoration and management
Vertical distributions of chlorophyll in deep, warm monomictic lakes

The factors affecting vertical distributions of chlorophyll fluorescence were examined in four temperate, warm monomictic lakes. Each of the lakes (maximum depth >80 m) was sampled over 2 years at intervals from monthly to seasonal. Profiles were taken of chlorophyll fluorescence (as a proxy for algal biomass), temperature and irradiance, as well as integrated samples from the surface mixed layer for chlorophyll a (chl a) and nutrient concentrations in each lake. Depth profiles of chlorophyll fluorescence were also made along transects of the longest axis of each lake. Chlorophyll fluorescence maxima occurred at depths closely correlated with euphotic depth (r ² = 0.67, P < 0.01), which varied with nutrient status of the lakes. While seasonal thermal density stratification is a prerequisite for the existence of a deep chlorophyll maximum (DCM), our study provides evidence that the depth of light penetration largely dictates the DCM depth during stratification. Reduction in water clarity through eutrophication can cause a shift in phytoplankton distributions from a DCM in spring or summer to a surface chlorophyll maximum within the surface mixed layer when the depth of the euphotic zone (z eu) is consistently shallower than the depth of the surface mixed layer (z SML). Trophic status has a key role in determining vertical distributions of chlorophyll in the four lakes, but does not appear to disrupt the annual cycle of maximum chlorophyll in winter
The trophic importance of epiphytic algae in a freshwater macrophyte system (Potamogeton perfoliatus L.): stable isotope and fatty acid analyses

Stable isotope and fatty acid analyses were used to study carbon sources for animals in a submerged plant bed. Epiphytes growing on Potamogeton perfoliatus, sand microflora, and alder leaves were the most important carbon sources. The most abundant macrophyte, P. perfoliatus was unimportant as a food source. Modelling (IsoSource) showed that epiphytes were the most important food source for the most abundant benthic invertebrates, the isopod Asellus aquaticus (annual mean contribution 64%), the amphipod Gammarus pulex (66%), and the gastropod Potamopyrgus antipodarum (83%). The mean annual contributions of sand microflora were, respectively, 21, 19, and 9%; and of alder leaves, 15, 15, and 8% for these three species. The relative importance of carbon sources varied seasonally. The relative contribution of epiphytes was lowest for all three grazer species in July: A. aquaticus 38%, G. pulex 43%, and P. antipodarum 42%. A decline in epiphyte biomass in summer may have caused this switch to less attractive food sources. P. perfoliatus provided habitat and shelter for consumers, but food was mainly supplied indirectly by providing space for attached epiphytes, which are fast-growing and provide a highly nutritious food source
Sources and fate of nutrients in a subtropical reservoir

This study examined the sources and fate of nutrient inputs from two principal tributaries to the eutrophic subtropical Wivenhoe reservoir: an unregulated river and a dammed river with regular releases, during a period of declining reservoir water levels. Nutrient budgets were constructed over a period of 6 years, and combined with short-term data on nutrient concentrations and forms, and d15N stable isotope data. Our study found that over a 6 year period, there was net retention of phosphorus (P) in the reservoir, with 60% of inputs retained. Most of the P input load came from the unregulated river, with an agricultural catchment, during periods of high flow. During one event half of the total TP load from the unregulated river in the study period was delivered in only 12 days. Much of the P was dissolved inorganic P (DIP) and was derived from high P concentrations in soils and sediments. This highlights the importance of appropriate catchment management practices to reduce P losses from terrestrial systems because retention of P in reservoir sediments reduces the availability of this nutrient for agricultural production. In contrast, there was negligible retention of nitrogen (N). The unregulated river was an important source of N derived from N fixation in the river and adjacent soils, while the source from the dammed river was mostly reprocessed N. The high retention of P relative to N is consistent with relatively higher accumulation of P in sediments.Griffith Sciences, Griffith School of EnvironmentFull Tex
Terrestrial invertebrates of dry river beds are not simply subsets of riparian assemblages

Dry river beds are common worldwide and are rapidly increasing in extent due to the effects of water management and prolonged drought periods due to climate change. While attention has been given to the responses of aquatic invertebrates to drying rivers, few studies exist on the terrestrial invertebrates colonizing dry river beds. Dry river beds are physically harsh and they often differ substantially in substrate, topography, microclimate and inundation frequency from adjacent riparian zones. Given these differences, we predicted that dry river beds provide a unique habitat for terrestrial invertebrates, and that their assemblage composition differs from that in adjacent riparian zones. Dry river beds and riparian zones in Australia and Italy were sampled for terrestrial invertebrates with pitfall traps. Sites differed in substrate type, climate and flow regime. Dry river beds contained diverse invertebrate assemblages and their composition was consistently different from adjacent riparian zones, irrespective of substrate, climate or hydrology. Although some taxa were shared between dry river beds and riparian zones, 66 of 320 taxa occurred only in dry river beds. Differences were due to species turnover, rather than shifts in abundance, indicating that dry river bed assemblages are not simply subsets of riparian assemblages. Some spatial patterns in invertebrate assemblages were associated with environmental variables (irrespective of habitat type), but these associations were statistically weak. We suggest that dry river beds are unique habitats in their own right. We discuss potential human stressors and management issues regarding dry river beds and provide recommendations for future research.Griffith Sciences, Griffith School of EnvironmentFull Tex
Actual state of European wetlands and their possible future in the context of global climate change

[EN] The present area of European wetlands is only a fraction of their area before the start of large-scale human colonization of Europe. Many European wetlands have been exploited and managed for various purposes. Large wetland areas have been drained and reclaimed mainly for agriculture and establishment of human settlements. These threats to European wetlands persist. The main responses of European wetlands to ongoing climate change will vary according to wetland type and geographical location. Sea level rise will probably be the decisive factor affecting coastal wetlands, especially along the Atlantic coast. In the boreal part of Europe, increased temperatures will probably lead to increased annual evapotranspiration and lower organic matter accumulation in soil. The role of vast boreal wetlands as carbon sinks may thus be suppressed. In central and western Europe, the risk of floods may support the political will for ecosystem-unfriendly flood defence measures, which may threaten the hydrology of existing wetlands. Southern Europe will probably suffer most from water shortage, which may strengthen the competition for water resources between agriculture, industry and settlements on the one hand and nature conservancy, including wetland conservation, on the other. © 2011 Springer Basel AG.Work on this paper was supported by the projects NPV 2B06023 and MSM 6007665801 of the Ministry of Education, Youth and Sports of the Czech Republic, 526/09/1545 of the Grant Agency of the Czech Republic and QH 82078 of the Czech National Agency of Agricultural Research. We warmly thank Hana Santruckova for helpful comments on the manuscript, Stepan Husak for providing the information on Coleanthus subtilis, Vaclav Nedbal for techical help with the compilation of the map of European wetlands (Fig. 1), Jakub Brom for providing photographs in Fig. 5, and Ondrej Novak for technical help with the preparation of the manuscriptPeer Reviewe
Effects of freshwater inputs on the lower trophic levels of a temperate estuary: physical, physiological or trophic forcing?

The online version of this article (doi:10.1007/s00027-011-0240-5) contains supplementary material, which is available to authorized users.The aim of this 6 year study was to assess whether freshwater inputs (rainfall and dam discharges) were acting as physical, physiological or trophic forcing factors on phytoplankton pigment concentrations and the dominant mysids of a temperate estuary (Guadalquivir estuary; SW, Spain). The effects of natural and human-controlled freshwater inputs modified the physico-chemical conditions and consequently biological production (bottom up control). Nutrient (nitrogen hypernutrification), suspended particulate matter and allochthonous photosynthetic pigment imports linked to freshwater inputs from adjacent habitats were observed, as well as light-limited autochthonous primary production. Seasonal and/or spatial patterns were shown by all study variables, including mysids. Freshwater management effects on dominant mysids differed depending on the species’ salinity tolerance (physiological forcing) and preferred prey availability (trophic forcing). Moreover, high inorganic matter content had a negative effect on the density of Mesopodopsis slabberi (physical forcing), which led to an increased detritivory/herbivory ratio (Neomysis integer/M. slabberi ratio). In conclusion, freshwater inputs appeared to effect estuarine lower trophic levels via a combination of different forcing mechanisms. Although several general patterns can be derived, the response of the system to freshwater inputs was not always univocal.The study was supported by the Spanish Ministry of Science and Innovation through the projects REN2000-0822 MAR and Consolider-Ingenio 2010 CSD2009-00065, the Environmental and Fishery Agency of Autonomous Andalusia Government ("Consejería de Medio Ambiente" and "Consejería de Agricultura y Pesca: Junta de Andalucía") and an EU Fishery Grant.Peer reviewe
Fine sediment on leaves : shredder removal of sediment does not enhance fungal colonisation

Inorganic fine sediments are easily carried into streams and rivers from disturbed land. These sediments can affect the stream biota, including detritivorous invertebrates (shredders) and impair ecosystem functions, such as leaf litter decomposition. We hypothesized that fine sediment (kaolin) deposited on leaves would reduce or suppress fungal development, reducing decomposition rates of leaves. Moreover, we predicted that shredders would act as ecosystem engineers by perturbing sediment deposition, reducing its impact on decomposition and fungi. We used a fully crossed experimental design of sediment addition (control, 400 mg L-1) and shredders (none, Gammarus, Potamophylax) in laboratory aquaria. Leaf mass loss, sus- pended solids, microbial respiration, fungal biomass and spore production were measured. Sediment addition had no significant effects on the leaf mass remaining nor on shredders’ consumption rates. However, sediment slightly reduced fungal assemblage richness and the sporulation rate of three fungal species. The presence of shredders sub- stantially increased the resuspension of fine sediments ([300%),resultinginhighersuspendedloads.However,the action of shredders did not have a significant effect on fungal biomass nor on leaf mass loss. Even if shredders did not enhance fungal colonisation, they affected the settle- ment of fine sediment, serving as allogenic engineers. Our study suggests that concentrations of fine sediment of 400 mg L-1 with short exposure times (192 h) can have some effect on leaf decomposition
Is net ecosystem production higher in natural relative to constructed wetlands?

28 páginas, 4 figuras, 3 tablas.[EN]Ecosystem metabolism is an important measure of wetland restoration efficiency, and serves to indicate if the system is capable of processing energetic resources. Despite its value, ecosystem metabolism has rarely been included in monitoring programs. In this study, we aimed to achieve the following objectives: (i) compare net ecosystem production (NEP) rates of constructed vs. natural wetlands; (ii) identify the highest NEP rate habitats; and (iii) define the main environmental factors regulating NEP in different wetland types. Pelagic and benthic NEP rates and physicochemical features were measured in three natural and five constructed wetlands in the middle Ebro River floodplain (NE Spain). Statistical analyses showed pelagic NEP rates peaked in natural wetlands, which produced up to 187.5 mg C m−3 h−1 compared to lower rates in constructed wetlands (up to 46.2 mg C m−3 h−1). Pelagic NEP responded positively to temperature, total dissolved solids, and nutrients. Benthic NEP rates were 3 to 30-fold greater than pelagic in natural (up to 994.9 mg C m−3 h−1) and constructed (up to 1,551.5 mg C m−3 h−1) wetlands, and were heavily influenced by habitat type, with NEP peaking in areas dominated by submerged vegetation and fine organic sediment. Rapid recovery in aquatic communities (i.e. macroinvertebrate diversity) has been previously reported for the studied wetlands; however, our study suggests a slower recovery of functional processes (i.e. pelagic NEP) in constructed habitats. We therefore strongly advocate the inclusion of ecosystem function in the design and evaluation of restoration projects to optimise long-term wetland ecosystem sustainability.This project was funded by the Spanish Ministry of Science and Innovation (National Research Plan CGL2008-\ud
05153-C02-01), the Aragon Government (Research Group E61 on\ud
Ecological Restoration; Applied Research Consolidated Group-GIMACES E02; and B079/09 pre-doctoral grant), the Caja\ud
Inmaculada—Aragon Government (Programa Europa XXI, CB31/11\ud
research mobility grant) and counted with the support of ‘‘APN\ud
Galachos Natural Reserve’’. We thank M. Garcı´a and A. Barcos for\ud
analysing water samples, and P. Sanchez, F. Carranza, L. Miguel and\ud
J. Garcı´a for their ﬁeld assistance and Write Science Right for English\ud
editing. We are also grateful to two anonymous reviewers whose\ud
comments highly improved the quality of this paper.Peer reviewe