Temporal Variation In The Carrying Capacity Of A Perennial Grass Population

Density dependence and, therefore, K (carrying capacity, equilibrium population size) are central to understanding and predicting changes in population size (N). Although resource levels certainly fluctuate, K has almost always been treated as constant in both theoretical and empirical studies. We quantified temporal variation in K by fitting extensions of standard population dynamic models to 16 annual censuses of a population of the perennial bunch-grass Bouteloua rigidiseta. Variable-K models provided substantially better fits to the data than did models that varied the potential rate of population increase. The distribution of estimated values of K was skewed, with a long right tail (i.e., a few >jackpot> years). The population did not track K closely. Relatively slow responses to changes in K combined with large, rapid changes in K sometimes caused N to be far from K. In 13%-20% of annual intervals, K was so much larger than N that the population's dynamics were best described by geometric growth and the population was, in effect, unregulated. Explicitly incorporating temporal variation in K substantially improved the realism of models with little increase in model complexity and provided novel information about this population's dynamics. Similar methods would be applicable to many other data sets.Integrative Biolog

Effective speed of sound in phononic crystals

A new formula for the effective quasistatic speed of sound $c$ in 2D and 3D periodic materials is reported. The approach uses a monodromy-matrix operator to enable direct integration in one of the coordinates and exponentially fast convergence in others. As a result, the solution for $c$ has a more closed form than previous formulas. It significantly improves the efficiency and accuracy of evaluating $c$ for high-contrast composites as demonstrated by a 2D example with extreme behavior.Comment: 4 pages, 1 figur

Rabbits and the Specious Origins of Domestication

Rabbits are commonly thought to have been domesticated in ∼AD600 by French monks. Using historical and archaeological records, and genetic methods, we demonstrate that this is a misconception and the general inability to date domestication stems from both methodological biases and the lack of appreciation of domestication as a continuum

New limits on anomalous contributions to the Wtb vertex

The authors would like to thank the Center for Theoretical Physics of the Physics Department at the New York City College of Technology, for providing computing power from their High-Performance Computing Cluster. The work of M.C.N. Fiolhais was supported by FCT Grant No. SFRH/BPD/100379/2014. The work of C. M. Pease was partly supported by Macaulay Honors College. The authors would also like to thank Juan Antonio Aguilar-Saavedra and Nuno F. Castro for a long time collaboration.The latest and most precise top quark measurements at the LHC and Tevatron are used to establish new limits on the Wtb vertex. Recent results on the measurements of the W-boson helicity fractions and single top quark production cross section are combined in order to establish new limits at 95% CL (confidence level). The allowed regions for these limits are presented, for the first time, in three-dimensional graphics, for both real and imaginary components of the different anomalous couplings, providing a new perspective on the impact of the combination of different physics observables. These results are also combined with the prospected future measurement of the single top quark production cross section and W-boson helicity fractions at the LHC.The authors would like to thank the Center for Theoretical Physics of the Physics Department at the New York City College of Technology, for providing computing power from their High-Performance Computing Cluster. The work of M.C.N. Fiolhais was supported by FCT Grant No. SFRH/BPD/100379/2014. TheworkofC.M.PeasewaspartlysupportedbyMacaulay Honors College. The authors would also like to thank Juan Antonio Aguilar-Saavedra and Nuno F. Castro for a long time collaboration

Use of ERTS-1 data to assess and monitor change in the Southern California environment

There are no author-identified significant results in this report

Global constraints on top quark anomalous couplings

The latest results on top quark physics, namely single top quark production cross sections, W-boson helicity and asymmetry measurements are used to probe the Lorentz structure of the Wtb vertex. The increase of sensitivity to new anomalous physics contributions to the top quark sector of the standard model is quantified by combining the relevant results from Tevatron and the Large Hadron Collider. The results show that combining an increasing set of available precision measurements in the search for new physics phenomena beyond the standard model leads to significant sensitivity improvements, especially when compared with the current expectation for the High Luminosity run at the LHC.This work was supported by the PSC-CUNY Grant 60061-00 48.info:eu-repo/semantics/publishedVersio

On the effective shear speed in 2D phononic crystals

The quasistatic limit of the antiplane shear-wave speed ('effective speed') $c$ in 2D periodic lattices is studied. Two new closed-form estimates of $c$ are derived by employing two different analytical approaches. The first proceeds from a standard background of the plane wave expansion (PWE). The second is a new approach, which resides in $\mathbf{x}$-space and centers on the monodromy matrix (MM) introduced in the 2D case as the multiplicative integral, taken in one coordinate, of a matrix with components being the operators with respect to the other coordinate. On the numerical side, an efficient PWE-based scheme for computing $c$ is proposed and implemented. The analytical and numerical findings are applied to several examples of 2D square lattices with two and three high-contrast components, for which the new PWE and MM estimates are compared with the numerical data and with some known approximations. It is demonstrated that the PWE estimate is most efficient in the case of densely packed stiff inclusions, especially when they form a symmetric lattice, while in general it is the MM estimate that provides the best overall fitting accuracy.Comment: 13 pages, 9 figure

North-South dialogues: reflecting on working transnationally with young men, masculinities and gender justice

Dialoguing across national borders and specifically global North-South centres and margins has increasingly been viewed as a way to enhance critical and feminist studies and engagement with men and masculinities. This article draws on narratives generated by a group of researchers in South Africa and Finland who have been engaged in a transnational research project that included a strong focus on young men, masculinities and gender and sexual justice. The piece provides an account of the nuanced and complex experiences and dynamics involved in transnational research collaboration, particularly within the framework on historical and continued inequalities between the global North and South. While obvious benefits are raised, this experience also foregrounds a range of challenges and constraints involved in transnational research collaboration within this field and possibly many others. Key learnings gleaned from this analysis of reported experiences and thoughts include the importance of careful, considered and critical reflexivity at all moments and at all levels, both in interpersonal and intergroup relations, as well as in public representation of collaborative work

Byzantine Gathering in Networks

This paper investigates an open problem introduced in [14]. Two or more mobile agents start from different nodes of a network and have to accomplish the task of gathering which consists in getting all together at the same node at the same time. An adversary chooses the initial nodes of the agents and assigns a different positive integer (called label) to each of them. Initially, each agent knows its label but does not know the labels of the other agents or their positions relative to its own. Agents move in synchronous rounds and can communicate with each other only when located at the same node. Up to f of the agents are Byzantine. A Byzantine agent can choose an arbitrary port when it moves, can convey arbitrary information to other agents and can change its label in every round, in particular by forging the label of another agent or by creating a completely new one. What is the minimum number M of good agents that guarantees deterministic gathering of all of them, with termination? We provide exact answers to this open problem by considering the case when the agents initially know the size of the network and the case when they do not. In the former case, we prove M=f+1 while in the latter, we prove M=f+2. More precisely, for networks of known size, we design a deterministic algorithm gathering all good agents in any network provided that the number of good agents is at least f+1. For networks of unknown size, we also design a deterministic algorithm ensuring the gathering of all good agents in any network but provided that the number of good agents is at least f+2. Both of our algorithms are optimal in terms of required number of good agents, as each of them perfectly matches the respective lower bound on M shown in [14], which is of f+1 when the size of the network is known and of f+2 when it is unknown

Probing the CP nature of the Higgs coupling in tt¯h events at the LHC

The determination of the CP nature of the Higgs coupling to top quarks is addressed in this paper, using t¯th events produced in √s=13  TeV proton-proton collisions at the LHC. Dileptonic final states are employed, with two oppositely charged leptons and four jets, corresponding to the decays t→bW+→bℓ+νℓ, ¯t→¯bW−→¯bℓ−¯νℓ, and h→b¯b. Pure scalar (h=H), pure pseudoscalar (h=A), and CP-violating Higgs boson signal events, generated with MadGraph5_aMC@NLO, are fully reconstructed through a kinematic fit. We furthermore generate samples that have both a CP-even and a CP-odd component in the t¯th coupling in order to probe the ratio of the two components. New angular distributions of the decay products, as well as CP angular asymmetries, are explored in order to separate the scalar from the pseudoscalar components of the Higgs boson and reduce the contribution from the dominant irreducible background, t¯tb¯b. Significant differences between the angular distributions and asymmetries are observed, even after the full kinematic fit reconstruction of the events, allowing to define the best observables for a global fit of the Higgs couplings parameters.info:eu-repo/semantics/publishedVersio