Temporal distribution of porcine circovirus 2 genogroups recovered from postweaning multisystemic wasting syndrome-affected and -nonaffected farms in Ireland and Northern Ireland

Porcine circovirus type 2 (PCV2) is now recognized as the essential infectious component of porcine postweaning multisystemic wasting syndrome (PMWS). PMWS was first recognized in high-status, specific pathogen-free pigs in Canada in 1991 and is now an economically important disease that affects the swine industry around the world. Recently, reports of genomic studies on PCV2 viruses indicated that 2 distinctive genogroups of PCV2 exist.(4,10) This report involves the results of a study on the distribution of predominant PCV2 genogroups recovered from samples taken from PMWS-affected and PMWS-nonaffected farms on the island of Ireland over a 9-year period and the results of a study on PCV2 genogroup recovery from fecal samples taken from a farm in Northern Ireland from 2003 to 2005 that was first diagnosed as PMWS positive in August 2005. The results indicate that, although at least 2 distinct genogroups of PCV2 have been circulating on pig farms on the island of Ireland, there does not appear to be a direct relationship between infection with these different genogroups of PCV2 and the development of PMWS.

Temporal and Urban Peripheries in Systems Thinking

The “Temporal and Urban Peripheries” is the fall project of the final year of the Architecture program of Izmir University of Economics in Turkey. With a critical and contextual look at the built environment, the studio focuses on the significance of the incorporation of history, urban design, and parametrics in architectural design. This short article presents the thrust of the studio, basic concepts, the process, and outcomes.

A spatio-temporal 2D-models framework for human pose recovery in monocular sequences

This paper addresses the pose recovery problem of a particular articulated object: the human body. In this model-based approach, the 2D-shape is associated to the corresponding stick figure allowing the joint segmentation and pose recovery of the subject observed in the scene. The main disadvantage of 2D-models is their restriction to the viewpoint. To cope with this limitation, local spatio-temporal 2D-models corresponding to many views of the same sequences are trained, concatenated and sorted in a global framework. Temporal and spatial constraints are then considered to build the probabilistic transition matrix (PTM) that gives a frame to frame estimation of the most probable local models to use during the fitting procedure, thus limiting the feature space. This approach takes advantage of 3D information avoiding the use of a complex 3D human model. The experiments carried out on both indoor and outdoor sequences have demonstrated the ability of this approach to adequately segment pedestrians and estimate their poses independently of the direction of motion during the sequence. (c) 2008 Elsevier Ltd. All rights reserved.

Exploiting spatio-temporal constraints for robust 2D pose tracking

We present a Spatio-temporal 2D Models Framework (STMF) for 2D-Pose tracking. Space and time are discretized and a mixture of probabilistic "local models" is learnt associating 2D Shapes and 2D Stick Figures. Those spatio-temporal models generalize well for a particular viewpoint and state of the tracked action but some spatio-temporal discontinuities can appear along a sequence, as a direct consequence of the discretization. To overcome the problem, we propose to apply a Rao-Blackwellized Particle Filter (RBPF) in the 2D-Pose eigenspace, thus interpolating unseen data between view-based clusters. The fitness to the images of the predicted 2D-Poses is evaluated combining our STMF with spatio-temporal constraints. A robust, fast and smooth human motion tracker is obtained by tracking only the few most important dimensions of the state space and by refining deterministically with our STMF.

Temporal extension of Laplacian Eigenmaps for unsupervised dimensionality reduction of time series

A novel non-linear dimensionality reduction method, called Temporal Laplacian Eigenmaps, is introduced to process efficiently time series data. In this embedded-based approach, temporal information is intrinsic to the objective function, which produces description of low dimensional spaces with time coherence between data points. Since the proposed scheme also includes bidirectional mapping between data and embedded spaces and automatic tuning of key parameters, it offers the same benefits as mapping-based approaches. Experiments on a couple of computer vision applications demonstrate the superiority of the new approach to other dimensionality reduction method in term of accuracy. Moreover, its lower computational cost and generalisation abilities suggest it is scalable to larger datasets. © 2010 IEEE.

Downregulation of the motA gene delays the escape of the obligate predator Bdellovibrio bacteriovorus 109J from bdelloplasts of bacterial prey cells

Bdellovibrio bacteriovorus is a Gram-negative bacterium that preys on other Gram-negative bacteria. The lifecycle of B. bacteriovorus alternates between an extracellular flagellated and highly motile non-replicative attack-phase cell and a periplasmic non-flagellated growth-phase cell. The prey bacterium containing periplasmic bdellovibrios becomes spherical but osmotically stable, forming a structure known as the bdelloplast. After completing the growth phase, newly formed bdellovibrios regain their flagellum and escape the bdelloplast into the environment, where they encounter more prey bacteria. The obligate predatory nature of B. bacteriovorus imposes a major difficulty to introducing mutations in genes directly involved in predation, since these mutants could be non-viable. This work reports the cloning of the B. bacteriovorus 109J motAB operon, encoding proteins from the flagellar motor complex, and a genetic approach based on the expression of a motA antisense RNA fragment to downregulate motility. Periplasmic bdellovibrios carrying the plasmid expressing antisense RNA displayed a marked delay in escaping from bdelloplasts, while the released attack-phase cells showed altered motility. These observations suggest that a functionally intact flagellar motor is required for the predatory lifecycle of B. bacteriovorus. Also, the use of antisense RNA expression may be a useful genetic tool to study the Bdellovibrio developmental cycle.

Events: Temporal and Eternal (in preparation)

This monograph develops a theory of events which provides the foundation for a plausible and coherent account of God’s relation to time, and which has independent appeal (independent, that is, of theological considerations). The book is divided into three parts. The first part involves an investigation of those fundamental aspects of time which have important implications for the nature of events, such as whether time is substantival or relational, and whether time is continuous, dense, or discrete. This part also includes a chapter on how these issues relate to different interpretations of the special theory of relativity. The second part involves a defense of the fundamentality of events, and the development of a theory of events in time. The third part considers ways in which we might plausibly conceive of events as eternal entities. This involves an investigation of different ways of characterizing divine eternity, and then an analysis of the possible relations these ways bear to the antecedently developed theory of temporal events. The thought here is that there are certain characteristics of temporal events which can be assimilated to eternity, and that by evaluating the extent to which different theories of divine eternity allow for this assimilation, we will be able to determine which of those theories is most plausible, and therefore which conception of God’s relation to time is most plausible. The basis of this evaluation will be the theory’s ability to coherently account for God’s knowledge of, and interaction with, the created temporal world. One specific issue here is how to account for God’s knowledge of the future free actions of humans (an issue that I address in 'Eternity, Knowledge, and Freedom'), but there are many other difficulties associated with God’s relation to time, such as God’s creation of contingent time, God’s knowledge of what is happening now, God’s dialogue with humans, and God’s causally interacting with the temporal world in general. A successful theory of eternal events, and, in particular, divine events, will provide a framework for dealing with these difficulties.

I have not yet sough a publisher for this work, but intend to do so in 2013, with a target publication date of 2014.

Assessing the extent to which temporal changes in waterbird community composition are driven by either local, regional or global factors.

1. Lough Neagh and Lough Beg Special Protection Area (SPA, hereafter Lough Neagh) is an important non-estuarine site in Britain and Ireland for overwintering wildfowl. Multivariate analysis of the winter counts showed a state-shift in the waterbird community following winter 2000/2001, mostly due to rapid declines in abundance (46–57% declines in the mean mid-winter January counts between 1993–2000 and 2002–2009) of members of the diving duck guild (pochard Aythya ferina, tufted duck Aythya fuligula and goldeneye Bucephala clangula) and coot (Fulica atra), a submerged macrophyte feeder.
2. Only pochard showed correlations between declines at Lough Neagh and those of overall species flyway population indices to suggest that global changes could contribute to declines at the site. However, indices from the Republic of Ireland showed no overall decline in the rest of Ireland. Tufted duck indices at the site were inversely related to indices in Great Britain. Lough Neagh goldeneye indices were positively correlated with indices in the Republic of Ireland and Great Britain, suggesting that short-stopping could contribute to declines at the site. Coot declines at Lough Neagh did not correlate with trends elsewhere, suggesting local factors involved in the decline.
3. These analyses indicate that although there are potentially different explanations for the dramatic declines in these four waterbird species at this site, the simultaneous nature of the declines across two feeding guilds strongly
suggest that local factors (such as loss of submerged macrophytes and benthic invertebrates) were involved. An assessment of the food supply, local disturbance and other factors at Lough Neagh is required to find an explanation for the observed adverse trends in wintering numbers of the affected species.
4. This study highlights the potential of waterbird community structure to reflect the status of aquatic systems, but confirms the need to establish site-specific factors responsible for the observed changes in abundance of key waterbird species at a site.

Spatial and temporal ecology of Scots pine ectomycorrhizas

Spatial analysis was used to explore the distribution of individual species in an ectomycorrhizal (ECM) fungal community to address: whether mycorrhizas of individual ECM fungal species were patchily distributed, and at what scale; and what the causes of this patchiness might be. Ectomycorrhizas were extracted from spatially explicit samples of the surface organic horizons of a pine plantation. The number of mycorrhizas of each ECM fungal species was recorded using morphotyping combined with internal transcribed spacer (ITS) sequencing. Semivariograms, kriging and cluster analyses were used to determine both the extent and scale of spatial autocorrelation in species abundances, potential interactions between species, and change over time. The mycorrhizas of some, but not all, ECM fungal species were patchily distributed and the size of patches differed between species. The relative abundance of individual ECM fungal species and the position of patches of ectomycorrhizas changed between years. Spatial and temporal analysis revealed a dynamic ECM fungal community with many interspecific interactions taking place, despite the homogeneity of the host community. The spatial pattern of mycorrhizas was influenced by the underlying distribution of fine roots, but local root density was in turn influenced by the presence of specific fungal species.