The complexity of weighted and unweighted #CSP

We give some reductions among problems in (nonnegative) weighted #CSP which restrict the class of functions that needs to be considered in computational complexity studies. Our reductions can be applied to both exact and approximate computation. In particular, we show that a recent dichotomy for unweighted #CSP can be extended to rational-weighted #CSP.Comment: 11 page

ALTERNATIVE METHODS OF ACCOUNTING FOR LIVESTOCK CAPITAL FORMATION: AN APPLICATION TO SOUTHERN U.S. AGRICULTURE

Livestock Production/Industries,

Defending Australia: a history of Australia’s defence white papers

This paper provides a summary of each of Australia’s defence white papers issued between 1976 and 2013 and seeks to draw out common themes that emerge in some or all of them. Executive summary Australia published defence white papers in 1976, 1987, 1994, 2000, 2009 and 2013 and a new white paper is expected in 2015. A community consultation process was undertaken as part of the 2000 and 2009 defence white papers and a similar process is being carried out for the upcoming 2015 defence white paper. The need to defend Australia against a major aggressor remains the primary driver in Australian defence policy. Regional security and contributing to the global order have been secondary, but still important priorities in Australian defence planning. Each of the defence white papers has been created on the basis that Australia should be able to defend itself against a potential aggressor without outside assistance (the principle of self-reliance), while at the same time stressing the importance of the alliance with the United States. Threat perceptions have changed from the Cold War influences reflected in the 1976 and 1987 white papers to a contemporary focus on terrorism while also incorporating emerging threats such as cyber attacks and the rise of China. Defence white papers are not produced in a vacuum but are informed by key reviews of Australia’s strategic situation, industry policy and force posture. Defence policy is subject to the broader economic conditions of the time and the Department of Defence must contend with many other priorities for government funding. The financial plans set out in the various defence white papers are often ambitious and rarely brought to fruition. On the whole, capability choices have displayed continuity between the different white papers regardless of changes in government. This is understandable given the length of time required for major capital equipment acquisitions. Recent white papers have placed a greater emphasis on regional engagement. The contribution of the Australian Defence Force (ADF) to humanitarian assistance and disaster relief operations, as well as to border protection activities, has also been included in the most recent white papers

The Comunero Uprising in Castile, 1520-1521: A Case Study for Early Modern Revolution

This thesis argues that scholars have ignored the Comunero rebellion’s importance as an instance of early modern revolution and that this uprising anticipates the revolutionary movements of the seventeenth and eighteenth centuries. The Leyenda Negra or Black Legend is primarily responsible for this oversight, as Protestant Europe has portrayed Spain as anachronistic and reactionary since the reign of Phillip II. This depiction has skewed both the Spanish and the European historical representations of Spain and pushed Spain onto the periphery of European history. This thesis uses the Comunero rebellion to identify these historiographical problems and suggests a way of viewing and using this movement to advance our understanding of early modern history

Stable isotope ecology of South African kelp forests

Kelp forests are some of the most productive coastal ecosystems in the world and provide numerous ecosystem goods and services. Where they occur, they play a key role in coastal ecology and local fisheries. In South Africa, Ecklonia maxima and Laminaria pallida form kelp forests which support diverse ecological communities. The species composition of these communities has been shown to be spatially variable along the South African coast, controlled by abiotic processes and species interactions. Despite their importance in the southern Benguela Current Large Marine Ecosystem (BCLME), large-scale research directed towards these habitats has largely waned over the past 30–40 years, prompting a renewed focus on these systems. Stable Isotope Analysis (SIA) is an indispensable tool for investigating food web characteristics, with particular focus on trophic structure and functioning. SIA can be used to understand the basal isotope variability in producers, determine the primary carbon sources of food webs, and investigate the spatial and temporal patterns in consumer isotope values and trophic niches. Unlike in other global kelp ecosystems, this methodology has not yet been applied to the kelp forests in South Africa. A study among eight geographically separate sites and two seasons highlights the natural variability of stable isotope values (δ13C and δ15N), at different spatial and temporal scales, within the two dominant kelp species. Additionally, stable isotope variability was investigated within and among different tissues within both kelp species. Within a kelp plant, δ13C values had a range of 1.65‰ for E. maxima and 1.52‰ for L. pallida. The δ15N values had a range of 3.75‰ for E. maxima and 4.21‰ for L. pallida. There were also consistent variability patterns along the length of a single frond in both species, for both isotopes. Among the localities, E. maxima and L. pallida were highly variable with ranges in δ13C (9.37‰ and 11.22‰) and δ15N (3.44‰ and 4.51‰) for the two species respectively. The δ13C values of L. pallida and E. maxima displayed a clear pattern coinciding with depth, particularly for L. pallida. Within-site variability was a major contributor to the overall spatial variability for both species. This provides further evidence for the importance of understanding basal variability of stable isotope values when determining the carbon sources of bottom-up controlled ecosystems. Variability in particulate organic matter (POM) composition is hypothesized to be related to upwelling processes in, and around, a typical west coast kelp forest. Various variables were used to characterise the composition, and determine the dynamics, of the POM along two transects (alongshore and off-shore) originating within a kelp forest. SIA was employed to estimate the contribution of kelp-derived detritus (KDD) to the POM present in the water column, using a unique approach for isolating phytoplankton and kelp end-member values. Under upwelling conditions, stable isotope analyses confirmed the dominance (>70%) of kelp detritus in POM samples, even at distances of 7.5 km off-shore. Under downwelling conditions, however, phytoplankton was dominant (>60%) along both transects. This study therefore highlights the importance of coastal processes such as upwelling for controlling the composition of POM in kelp forests, as well as illustrating how the natural variability in POM composition created by upwelling processes can be used to gather POM endmember isotope values. Three ecologically distinct kelp forest communities were investigated using a combination of SIA and community-wide niche metrics ('Layman metrics’ and Bayesian inferences). Three kelp forests, with differing community composition were selected, including a west coast kelp forest, a False Bay kelp forest and a lobster-invaded kelp forest located east of Cape Hangklip at Betty’s Bay. Temporal and spatial variability in stable isotope values was identified in producer and consumer stable isotope values, but was variable among species. Community-wide metrics showed clear seasonal patterns, but despite large differences in community structure, metrics were not vastly different among sites. Seasonal variability was the largest observable trend in metrics at all sites. Community niche areas showed a high degree of overlap (80–95%) further illustrating the similarity among sites and seasons. These findings are largely contrary to expected patterns from community composition data. Trophic position and isotope niche of the West Coast Rock Lobster (Jasus lalandii) was determined at three ecologically different kelp forest habitats, located in Marine Protected Areas in south-western South Africa. Temporal and spatial variability in trophic position and niche size were detected. The stable isotope niche and trophic position of lobsters at Betty’s Bay were markedly different from those at Oudekraal and Bordjiesrif, with the summer niche being distinct (0% overlap). Trophic position was lowest at the lobster-invaded Betty’s Bay (2.52) and highest at Bordjiesrif (3.16). Similarly, the isotope niche of Jasus lalandii was significantly constricted at Betty’s Bay compared to the other two study sites. Primarily, these results show that in the region where these lobsters have invaded, the trophic niche is considerably constricted. This likely to be a consequence of the higher densities of lobsters in this area. These findings highlight the influence of the lobster invasion on Jasus lalandii itself, adding to the already published ecological effects on the kelp forest ecosystem as a whole. These findings also highlight the differences in trophic niche of this species, despite the overall community niche showing little difference among sites. The findings of this thesis provide estimates of the variability in stable isotope values of kelp forest seaweeds and consumers, as well as addressing the importance of ocean processes such as upwelling in controlling POM composition in kelp forests. Additionally, the trophic niche of a key kelp forest predator was characterised in ecologically different kelp forests, providing evidence of the effect of community structure on the niche of this species. This is the first concerted research effort into the stable isotope ecology of South African kelp forests, providing an updated look at the ecology of these important ecosystems, and serves as a foundation for future studies of this type

Stable isotope ecology of South African kelp forests

Kelp forests are some of the most productive coastal ecosystems in the world and provide numerous ecosystem goods and services. Where they occur, they play a key role in coastal ecology and local fisheries. In South Africa, Ecklonia maxima and Laminaria pallida form kelp forests which support diverse ecological communities. The species composition of these communities has been shown to be spatially variable along the South African coast, controlled by abiotic processes and species interactions. Despite their importance in the southern Benguela Current Large Marine Ecosystem (BCLME), large-scale research directed towards these habitats has largely waned over the past 30–40 years, prompting a renewed focus on these systems. Stable Isotope Analysis (SIA) is an indispensable tool for investigating food web characteristics, with particular focus on trophic structure and functioning. SIA can be used to understand the basal isotope variability in producers, determine the primary carbon sources of food webs, and investigate the spatial and temporal patterns in consumer isotope values and trophic niches. Unlike in other global kelp ecosystems, this methodology has not yet been applied to the kelp forests in South Africa. A study among eight geographically separate sites and two seasons highlights the natural variability of stable isotope values (δ13C and δ15N), at different spatial and temporal scales, within the two dominant kelp species. Additionally, stable isotope variability was investigated within and among different tissues within both kelp species. Within a kelp plant, δ13C values had a range of 1.65‰ for E. maxima and 1.52‰ for L. pallida. The δ15N values had a range of 3.75‰ for E. maxima and 4.21‰ for L. pallida. There were also consistent variability patterns along the length of a single frond in both species, for both isotopes. Among the localities, E. maxima and L. pallida were highly variable with ranges in δ13C (9.37‰ and 11.22‰) and δ15N (3.44‰ and 4.51‰) for the two species respectively. The δ13C values of L. pallida and E. maxima displayed a clear pattern coinciding with depth, particularly for L. pallida. Within-site variability was a major contributor to the overall spatial variability for both species. This provides further evidence for the importance of understanding basal variability of stable isotope values when determining the carbon sources of bottom-up controlled ecosystems. Variability in particulate organic matter (POM) composition is hypothesized to be related to upwelling processes in, and around, a typical west coast kelp forest. Various variables were used to characterise the composition, and determine the dynamics, of the POM along two transects (alongshore and off-shore) originating within a kelp forest. SIA was employed to estimate the contribution of kelp-derived detritus (KDD) to the POM present in the water column, using a unique approach for isolating phytoplankton and kelp end-member values. Under upwelling conditions, stable isotope analyses confirmed the dominance (>70%) of kelp detritus in POM samples, even at distances of 7.5 km off-shore. Under downwelling conditions, however, phytoplankton was dominant (>60%) along both transects. This study therefore highlights the importance of coastal processes such as upwelling for controlling the composition of POM in kelp forests, as well as illustrating how the natural variability in POM composition created by upwelling processes can be used to gather POM endmember isotope values. Three ecologically distinct kelp forest communities were investigated using a combination of SIA and community-wide niche metrics ('Layman metrics’ and Bayesian inferences). Three kelp forests, with differing community composition were selected, including a west coast kelp forest, a False Bay kelp forest and a lobster-invaded kelp forest located east of Cape Hangklip at Betty’s Bay. Temporal and spatial variability in stable isotope values was identified in producer and consumer stable isotope values, but was variable among species. Community-wide metrics showed clear seasonal patterns, but despite large differences in community structure, metrics were not vastly different among sites. Seasonal variability was the largest observable trend in metrics at all sites. Community niche areas showed a high degree of overlap (80–95%) further illustrating the similarity among sites and seasons. These findings are largely contrary to expected patterns from community composition data. Trophic position and isotope niche of the West Coast Rock Lobster (Jasus lalandii) was determined at three ecologically different kelp forest habitats, located in Marine Protected Areas in south-western South Africa. Temporal and spatial variability in trophic position and niche size were detected. The stable isotope niche and trophic position of lobsters at Betty’s Bay were markedly different from those at Oudekraal and Bordjiesrif, with the summer niche being distinct (0% overlap). Trophic position was lowest at the lobster-invaded Betty’s Bay (2.52) and highest at Bordjiesrif (3.16). Similarly, the isotope niche of Jasus lalandii was significantly constricted at Betty’s Bay compared to the other two study sites. Primarily, these results show that in the region where these lobsters have invaded, the trophic niche is considerably constricted. This likely to be a consequence of the higher densities of lobsters in this area. These findings highlight the influence of the lobster invasion on Jasus lalandii itself, adding to the already published ecological effects on the kelp forest ecosystem as a whole. These findings also highlight the differences in trophic niche of this species, despite the overall community niche showing little difference among sites. The findings of this thesis provide estimates of the variability in stable isotope values of kelp forest seaweeds and consumers, as well as addressing the importance of ocean processes such as upwelling in controlling POM composition in kelp forests. Additionally, the trophic niche of a key kelp forest predator was characterised in ecologically different kelp forests, providing evidence of the effect of community structure on the niche of this species. This is the first concerted research effort into the stable isotope ecology of South African kelp forests, providing an updated look at the ecology of these important ecosystems, and serves as a foundation for future studies of this type

The Complexity of Weighted Boolean #CSP with Mixed Signs

We give a complexity dichotomy for the problem of computing the partition function of a weighted Boolean constraint satisfaction problem. Such a problem is parameterized by a set of rational-valued functions, which generalize constraints. Each function assigns a weight to every assignment to a set of Boolean variables. Our dichotomy extends previous work in which the weight functions were restricted to being non-negative. We represent a weight function as a product of the form (-1)^s g, where the polynomial s determines the sign of the weight and the non-negative function g determines its magnitude. We show that the problem of computing the partition function (the sum of the weights of all possible variable assignments) is in polynomial time if either every weight function can be defined by a "pure affine" magnitude with a quadratic sign polynomial or every function can be defined by a magnitude of "product type" with a linear sign polynomial. In all other cases, computing the partition function is FP^#P-complete.Comment: 24 page