Analysis using large-scale ringing data

Birds are highly mobile organisms and there is increasing evidence that studies at large spatial scales are needed if we are to properly understand their population dynamics. While classical metapopulation models have rarely proved useful for birds, more general metapopulation ideas involving collections of populations interacting within spatially structured landscapes are highly relevant (Harrison, 1994). There is increasing interest in understanding patterns of synchrony, or lack of synchrony, between populations and the environmental and dispersal mechanisms that bring about these patterns (Paradis et al., 2000). To investigate these processes we need to measure abundance, demographic rates and dispersal at large spatial scales, in addition to gathering data on relevant environmental variables. There is an increasing realisation that conservation needs to address rapid declines of common and widespread species (they will not remain so if such trends continue) as well as the management of small populations that are at risk of extinction. While the knowledge needed to support the management of small populations can often be obtained from intensive studies in a few restricted areas, conservation of widespread species often requires information on population trends and processes measured at regional, national and continental scales (Baillie, 2001). While management prescriptions for widespread populations may initially be developed from a small number of local studies or experiments, there is an increasing need to understand how such results will scale up when applied across wider areas. There is also a vital role for monitoring at large spatial scales both in identifying such population declines and in assessing population recovery. Gathering data on avian abundance and demography at large spatial scales usually relies on the efforts of large numbers of skilled volunteers. Volunteer studies based on ringing (for example Constant Effort Sites [CES]; Peach et al., 1998; DeSante et al., 2001) are generally co–ordinated by ringing centres such as those that make up the membership of EURING. In some countries volunteer census work (often called Breeding Bird Surveys) is undertaken by the same organizations while in others different bodies may co–ordinate this aspect of the work. This session was concerned with the analysis of such extensive data sets and the approaches that are being developed to address the key theoretical and applied issues outlined above. The papers reflect the development of more spatially explicit approaches to analyses of data gathered at large spatial scales. They show that while the statistical tools that have been developed in recent years can be used to derive useful biological conclusions from such data, there is additional need for further developments. Future work should also consider how to best implement such analytical developments within future study designs. In his plenary paper Andy Royle (Royle, 2004) addresses this theme directly by describing a general framework for modelling spatially replicated abundance data. The approach is based on the idea that a set of spatially referenced local populations constitutes a metapopulation, within which local abundance is determined as a random process. This provides an elegant and general approach in which the metapopulation model as described above is combined with a data–generating model specific to the type of data being analysed to define a simple hierarchical model that can be analysed using conventional methods. It should be noted, however, that further software development will be needed if the approach is to be made readily available to biologists. The approach is well suited to dealing with sparse data and avoids the need for data aggregation prior to analysis. Spatial synchrony has received most attention in studies of species whose populations show cyclic fluctuations, particularly certain game birds and small mammals. However, synchrony is in fact a much more widespread process, with bird populations across wide areas showing similar trends and fluctuations as a result of common climatic and environmental factors (Paradis et al., 2000). Dispersal may also play an important role in such synchrony but its role is less well understood. Nigel Yoccoz and Rolf Ims (Yoccoz & Ims, 2004) show how synchrony can be investigated using data at three spatial scales taken from their field studies of the population dynamics of small mammals in North Norway. Small mammal abundance was estimated from trapping data using closed population models and also from total numbers of individuals captured. They use simulated data to show that synchrony, measured by the correlation coefficients between time series, was biased low by up to 30% when sampling variation was ignored. Appropriate analysis of such data will require simultaneous modelling of process and sampling variation, for example through the use of state–space models (Buckland et al., 2004). This view links back nicely to the approaches proposed by Andy Royle (Royle, 2004). Cycles in the abundance of small mammals have major affects on the demography of their predators, as is shown in the paper by Pertti Saurola and Charles Francis (Saurola & Francis, 2004). They report on the design and results of large–scale, long–term studies of owl populations by a network of amateur bird ringers in Finland. They show that breeding success varies with the stage of the microtine cycle. They also show how their data can be used to estimate dispersal over large spatial scales and illustrate the importance of correcting for uneven spatial variation in sampling effort. Further results from this study are reported in a companion paper within the population dynamics session (Francis & Saurola, 2004). Multi–species analyses of population dynamics are developed further in the paper by Romain Julliard (Julliard, 2004). He combines counts from the French Breeding Bird Survey with survival and recruitment estimates from the French CES scheme to assess the relative contributions of survival and recruitment to overall population changes. He develops a novel approach to modelling survival rates from such multi–site data by using within–year recaptures to provide a covariate of between–year recapture rates. This provided parsimonious models of variation in recapture probabilities between sites and years. The approach provides promising results for the four species investigated and can potentially be extended to similar data from other CES/MAPS schemes. The final paper by Blandine Doligez, David Thomson and Arie van Noordwijk (Doligez et al., 2004) illustrates how large-scale studies of population dynamics can be important for evaluating the effects of conservation measures. Their study is concerned with the reintroduction of White Stork populations to the Netherlands where a re–introduction programme started in 1969 had resulted in a breeding population of 396 pairs by 2000. They demonstrate the need to consider a wide range of models in order to account for potential age, time, cohort and "trap–happiness" effects. As the data are based on resightings such trap–happiness must reflect some form of heterogeneity in resighting probabilities. Perhaps surprisingly, the provision of supplementary food did not influence survival, but it may have had an indirect effect via the alteration of migratory behaviour. Spatially explicit modelling of data gathered at many sites inevitably results in starting models with very large numbers of parameters. The problem is often complicated further by having relatively sparse data at each site, even where the total amount of data gathered is very large. Both Julliard (2004) and Doligez et al. (2004) give explicit examples of problems caused by needing to handle very large numbers of parameters and show how they overcame them for their particular data sets. Such problems involve both the choice of appropriate starting models for sparse data and the speed with which convergence is achieved. Further analytical and software developments are needed in order to make it easier to analyse such data sets

Quantum Heating of a nonlinear resonator probed by a superconducting qubit

We measure the quantum fluctuations of a pumped nonlinear resonator, using a superconducting artificial atom as an in-situ probe. The qubit excitation spectrum gives access to the frequency and temperature of the intracavity field fluctuations. These are found to be in agreement with theoretical predictions; in particular we experimentally observe the phenomenon of quantum heating

Sensitivity optimization in quantum parameter estimation

We present a general framework for sensitivity optimization in quantum parameter estimation schemes based on continuous (indirect) observation of a dynamical system. As an illustrative example, we analyze the canonical scenario of monitoring the position of a free mass or harmonic oscillator to detect weak classical forces. We show that our framework allows the consideration of sensitivity scheduling as well as estimation strategies for non-stationary signals, leading us to propose corresponding generalizations of the Standard Quantum Limit for force detection.Comment: 15 pages, RevTe

Circuit QED with a Nonlinear Resonator : ac-Stark Shift and Dephasing

We have performed spectroscopic measurements of a superconducting qubit dispersively coupled to a nonlinear resonator driven by a pump microwave field. Measurements of the qubit frequency shift provide a sensitive probe of the intracavity field, yielding a precise characterization of the resonator nonlinearity. The qubit linewidth has a complex dependence on the pump frequency and amplitude, which is correlated with the gain of the nonlinear resonator operated as a small-signal amplifier. The corresponding dephasing rate is found to be close to the quantum limit in the low-gain limit of the amplifier.Comment: Paper : 4 pages, 3 figures; Supplementary material : 1 page, 1 figur

Tasas de dispersión y supervivencia de adultos y juveniles del rabijunco colirrojo (Phaethon rubricauda) expuestas a contaminantes potenciales

Annual survival and dispersal rates of adult and juvenile red–tailed tropicbirds were examined in connection with exposure to heavy metals. From 1990–2000 the incineration of a U.S. stockpile of chemical weapons stored at Johnston Atoll exposed nesting tropicbirds to increased levels of human disturbance, smoke stack emissions and potential leaks. Using a multi–state mark–recapture modeling approach, birds nesting in this site (downwind of the plant) were compared to those nesting in a reference site (upwind of the plant) with less human disturbance, no exposure to smoke stack emissions or other potential incineration emissions. We did not find any difference in survival of adults or juveniles when comparing the two sites. Adult breeding dispersal rates did not differ between the sites but we did find differences in the age–specific natal dispersal rates. Birds fledged from downwind areas were less likely to return to their natal area to nest and more likely to immigrate to the upwind area than vice–versa. This asymmetry in emigration rates is believed to be due to differing vegetation densities and has implications for vegetation management in relation to tropicbird nest success and population size.Se examinaron las tasas de dispersión y de supervivencia anual de adultos y jóvenes de los rabijuncos colirrojos en relación a la exposición a metales pesados. Entre los años 1990 y 2000, la incineración de un arsenal de armas químicas del ejército de Estados Unidos almacenadas en Johnston Atoll expuso a las aves del trópico que anidaban en la zona a niveles más elevados de perturbaciones antrópicas/contaminación humana, emisiones procedentes de chimeneas y fugas potenciales. Se comparó las aves nidificantes en este lugar (a favor del viento de la planta) mediante modelos de captura–recaptura de multiestados, con las que anidaban en un emplazamiento de referencia (en cuyo caso la planta quedaba situada en contra del viento), caracterizado por menos perturbaciones antrópicas y ninguna exposición a emisiones procedentes de chimeneas ni a ningún otro tipo de emisiones potenciales de incineración. Al comparar ambos emplazamientos, no se halló ninguna diferencia en cuanto a la supervivencia de las aves adultas o jóvenes. Las tasas de dispersión reproductiva de los adultos no difirieron entre los emplazamientos; en cambio, sí que se observaron diferencias en las tasas de dispersión natal por edades. Las aves jóvenes que abandonaron las áreas situadas a favor del viento era menos probable que regresaran a su área natal para anidar y más probable que inmigraran al área situada en contra del viento. Se considera que esta asimetría en las tasas de emigración obedece a las diferentes densidades de vegetación, repercutiendo en la gestión de la vegetación con respecto al éxito de los nidos de las aves del trópico y el tamaño poblacional

Quantum control on entangled bipartite qubits

Ising interaction between qubits could produce distortion in entangled pairs generated for engineering purposes (as in quantum computation) in presence of parasite magnetic fields, destroying or altering the expected behavior of process in which is projected to be used. Quantum control could be used to correct that situation in several ways. Sometimes the user should be make some measurement upon the system to decide which is the best control scheme; other posibility is try to reconstruct the system using similar procedures without perturbate it. In the complete pictures both schemes are present. We will work first with pure systems studying advantages of different procedures. After, we will extend these operations when time of distortion is uncertain, generating a mixed state, which needs to be corrected by suposing the most probably time of distortion.Comment: 10 pages, 5 figure

The negatively charged nitrogen-vacancy centre in diamond: the electronic solution

The negatively charged nitrogen-vacancy centre is a unique defect in diamond that possesses properties highly suited to many applications, including quantum information processing, quantum metrology, and biolabelling. Although the unique properties of the centre have been extensively documented and utilised, a detailed understanding of the physics of the centre has not yet been achieved. Indeed there persists a number of points of contention regarding the electronic structure of the centre, such as the ordering of the dark intermediate singlet states. Without a sound model of the centre's electronic structure, the understanding of the system's unique dynamical properties can not effectively progress. In this work, the molecular model of the defect centre is fully developed to provide a self consistent model of the complete electronic structure of the centre. The application of the model to describe the effects of electric, magnetic and strain interactions, as well as the variation of the centre's fine structure with temperature, provides an invaluable tool to those studying the centre and a means to design future empirical and ab initio studies of this important defect.Comment: 24 pages, 6 figures, 10 table

Glassy Solutions of the Kardar-Pasrisi-Zhang Equation

It is shown that the mode-coupling equations for the strong-coupling limit of the KPZ equation have a solution for d>4 such that the dynamic exponent z is 2 (with possible logarithmic corrections) and that there is a delta function term in the height correlation function = (A/k^{d+4-z}) \delta(w/k^z) where the amplitude A vanishes as d -> 4. The delta function term implies that some features of the growing surface h(x,t) will persist to all times, as in a glassy state.Comment: 11 pages, Revtex, 1 figure available upon request (same as figure 1 in ref [10]) Important corrections have been made which yield a much simpler picture of what is happening. We still find "glassy" solutions for d>4 where z is 2 (with possible logarithmic corrections). However, we now find no glassy solutions below d=4. A (linear) stability analysis (for d>4) has been included. Also one Author has been adde

Deception and self-awareness

This paper presents a study conducted for the Shades of Grey EPSRC research project (EP/H02302X/1), which aims to develop a suite of interventions for identifying terrorist activities. The study investigated the body movements demonstrated by participants while waiting to be interviewed, in one of two conditions: preparing to lie or preparing to tell the truth. The effect of self-awareness was also investigated, with half of the participants sitting in front of a full length mirror during the waiting period. The other half faced a blank wall. A significant interaction was found for the duration of hand/arm movements between the deception and self-awareness conditions (F=4.335, df=1;76, p<0.05). Without a mirror, participants expecting to lie spent less time moving their hands than those expecting to tell the truth; the opposite was seen in the presence of a mirror. This finding indicates a new research area worth further investigation