2-Vertex Connectivity in Directed Graphs

We complement our study of 2-connectivity in directed graphs, by considering the computation of the following 2-vertex-connectivity relations: We say that two vertices v and w are 2-vertex-connected if there are two internally vertex-disjoint paths from v to w and two internally vertex-disjoint paths from w to v. We also say that v and w are vertex-resilient if the removal of any vertex different from v and w leaves v and w in the same strongly connected component. We show how to compute the above relations in linear time so that we can report in constant time if two vertices are 2-vertex-connected or if they are vertex-resilient. We also show how to compute in linear time a sparse certificate for these relations, i.e., a subgraph of the input graph that has O(n) edges and maintains the same 2-vertex-connectivity and vertex-resilience relations as the input graph, where n is the number of vertices.Comment: arXiv admin note: substantial text overlap with arXiv:1407.304

Semi-dynamic connectivity in the plane

Motivated by a path planning problem we consider the following procedure. Assume that we have two points $s$ and $t$ in the plane and take $\mathcal{K}=\emptyset$. At each step we add to $\mathcal{K}$ a compact convex set that does not contain $s$ nor $t$. The procedure terminates when the sets in $\mathcal{K}$ separate $s$ and $t$. We show how to add one set to $\mathcal{K}$ in $O(1+k\alpha(n))$ amortized time plus the time needed to find all sets of $\mathcal{K}$ intersecting the newly added set, where $n$ is the cardinality of $\mathcal{K}$, $k$ is the number of sets in $\mathcal{K}$ intersecting the newly added set, and $\alpha(\cdot)$ is the inverse of the Ackermann function

Uterine adenocarcinoma with abdominal metastases in an ovariohysterectomised female cat

An adenocarcinoma of the uterine stump with abdominal metastases is described in a 12-year-old incompletely ovariohysterectomised female Domestic Short Haired (DSH) cat. At the time of presentation the adenocarcinoma had metastasised to the right peri-renal lymph node, the abdominal aorta, and the right ureter, resulting in the formation of a large cystic structure. This had compressed and displaced surrounding structures including the abdominal vena cava and the right kidney, and formed multiple adhesions to the body wall and adjacent abdominal structures. Metastatic extension to the aorta had resulted in its regression into a 2mm diameter non-pulsatile vessel

Livelihood Diversification In Coastal and Inland Fishing Communities: Misconceptions, Evidence and Implications for Fisheries Management

This is the working paper regarding the Sustainable Fisheries Livelihoods Programme (SFLP). Diversification is a process by which households engage in multiple income generating activities. It is widely seen in the academic literature and international development arena as a strategy for spreading risk and reducing vulnerability. The formulation of policies promoting diversification is thus encouraged at national levels to alleviate poverty. However, such policies involve delicate choices and trade-offs between government objectives of development, e.g. intensification of agriculture and increase in agricultural outputs to satisfy export markets, versus increased household well-being and resilience to adversity through the promotion of small-scale, household-based, activities. In the context of fisheries, diversification is promoted as a means for reducing dependence on the resource, making restrictive management easier and less controversial for those affected by such measures. This often interprets diversification as job-substitution (stop fishing, do something else) rather than adding other activities to an income-portfolio. With the tendency for increasing pressure on fishery resources, it becomes ever more necessary to address in a coherent way diversification and its links with both poverty reduction and responsible fisheries. Implications of the development of alternative or complementary activities alongside a main, resource-dependent activity such as fishing, may echo those experienced by sectors such as agriculture and pastoralism. However, many characteristics of the fishing activity and of those who engage in it are particular to the sector. General poverty alleviation policies and fisheries management schemes have been found to lack the necessary differentiation and to fail to cater for the specific needs of fishing communities (Smith et al. 2005). The lack of attention -- or misplaced attention through maladapted policies -- that the sector and the communities it supports have received so far can be traced to a number of misconceptions stemming from "the old paradigm on poverty in small-scale fisheries" (Béné, 2003, p950). These assumptions include that (after Béné 2003, Allison and Ellis 2001): -- Fishing is an ingrained activity in fishing communities and fishermen will not leave fishing for cultural reasons. -- Fishermen are specialised and carry out fishing on a professional basis only. -- Fishing is a last resort activity and fishermen are unable to diversify into other income-generating activities. -- Fisheries development and development of fishing communities is not possible without increasing fishing effort. -- Livelihood diversification in fishing communities cannot go hand in hand with a sustainable natural resources management that encompasses both sustainable fisheries management and poverty alleviation. It is the aim of this paper to challenge these assumptions. Because of its linkages with resource management, looking at diversification in fishing communities involves re-exploring the issue from a different perspective than its current interpretation and most widely-encountered application to agricultural (land-based)-livelihoods. Despite the potential broad remit of this task, the objective here is to remain focused on the necessity to dispel misconceptions and show the need to formulate policies that support the engagement of fisherfolk and their families in multiple activities. By doing so, the paper shall also provide a compilation and review of available information related to diversification in fishing communities and point out the complexity of the issue of diversification in these communities. The geographical scope of the paper is global, guided by the availability of case study material, though reference to the West African experiences of the Sustainable Fisheries Livelihoods Programme (SFLP) is made wherever possible. Unless expressed otherwise, the terms 'fisheries' or 'fishers' make implicit reference to artisanal fisheries and the small-scale operations and modus operandi of those relying on them

Tabulations of static pressure coefficients on the surfaces of 3 pylon-mounted axisymmetric flow-through nacelles at Mach numbers from 0.40 to 0.98

Three flow through nacelles mounted on an 82 deg swept pylon (10 percent thickness-to-chord ratio) were tested in the Langley 16 foot Transonic Tunnel. The long uncambered pylon was supported from a small body of revolution so that pressure measurements on the nacelle and pylon represent a pylon nacelle flow field without a wing present. Two nacelles had NACA 1-85-100 inlets and different circular arc afterbodies. The third nacelle had an NACA 1-70-100 inlet with a circular arc afterbody having the same external shape as one of the other nacelles. Nacelle length to maximum diameter ratio was 3.5. Data were obtained at angles of attack from 2 deg to 8 deg at selected Mach numbers

Z2SAL: a translation-based model checker for Z

Despite being widely known and accepted in industry, the Z formal specification language has not so far been well supported by automated verification tools, mostly because of the challenges in handling the abstraction of the language. In this paper we discuss a novel approach to building a model-checker for Z, which involves implementing a translation from Z into SAL, the input language for the Symbolic Analysis Laboratory, a toolset which includes a number of model-checkers and a simulator. The Z2SAL translation deals with a number of important issues, including: mapping unbounded, abstract specifications into bounded, finite models amenable to a BDD-based symbolic checker; converting a non-constructive and piecemeal style of functional specification into a deterministic, automaton-based style of specification; and supporting the rich set-based vocabulary of the Z mathematical toolkit. This paper discusses progress made towards implementing as complete and faithful a translation as possible, while highlighting certain assumptions, respecting certain limitations and making use of available optimisations. The translation is illustrated throughout with examples; and a complete working example is presented, together with performance data

Radio Spectra and NVSS Maps of Decametric Sources

We constructed radio spectra for ~1400 UTR-2 sources and find that 46% of them have concave curvature. Inspection of NVSS maps of 700 UTR sources suggests that half of all UTR sources are either blends of two or more sources or have an ultra-steep spectrum (USS). The fraction of compact USS sources in UTR may be near 10%. Using NVSS and the Digitized Sky Survey(s) we expect to double the UTR optical identification rate from currently ~19%.Comment: 2 pages, no figures; to appear in Proc. "Observational Cosmology with the New Radio Surveys", eds. M. Bremer, N. Jackson & I. Perez-Fournon, Kluwer Acad. Pres

Inequivalent contact structures on Boothby-Wang 5-manifolds

We consider contact structures on simply-connected 5-manifolds which arise as circle bundles over simply-connected symplectic 4-manifolds and show that invariants from contact homology are related to the divisibility of the canonical class of the symplectic structure. As an application we find new examples of inequivalent contact structures in the same equivalence class of almost contact structures with non-zero first Chern class.Comment: 27 pages; to appear in Math. Zeitschrif

Stable isotopes confirm the Banwell Bone Cave Mammal Assemblage Zone represents an MIS 5 fauna

The position of the Banwell Bone Cave mammal assemblage zone (MAZ) in the mammalian biostratigraphy of the British Isles has been the focus of debate for decades. Dominated by fauna typical of cold environments it was originally linked to the marine oxygen isotope stage (MIS) 4 stadial (ca. 72–59 ka). Subsequently it was argued that the Banwell Bone Cave MAZ more likely relates to the temperate interstadial of MIS 5a (ca. 86–72 ka). It is envisioned that “cold fauna” such as bison and reindeer moved into Britain during stadial MIS 5b (ca. 90 ka) and were subsequently isolated by the rising sea level during MIS 5a. Here we investigate environmental conditions during the Banwell Bone Cave MAZ using bone collagen δ13C and δ15N and tooth enamel δ18O and δ13C isotope analysis. We analyse bison and reindeer from the MAZ type-site, Banwell Bone Cave. Our results show unusually high δ15N values, which we ascribe to arid conditions within a temperate environment. Palaeotemperature estimates derived from enamel δ18O indicate warm temperatures, similar to present day. These results confirm that the Banwell Bone Cave MAZ relates to a temperate interstadial and supports its correlation to MIS 5a rather than MIS 4

The androgen receptor and signal-transduction pathways in hormone-refractory prostate cancer. Part 1: modifications to the androgen receptor

Prostate cancer is the second most common male malignancy in the western world an increasing incidence in an ageing population. Treatment of advanced prostate cancer relies on androgen deprivation. Although the majority of patients initially respond favourably to androgen deprivation therapy, the mean time to relapse is 12-18 months. Currently there are few treatments available for men who have developed resistance to hormone therapy, due to the lack of understanding of the molecular mechanisms underlying development of this disease. Recently, however, major advances have been made in understanding both androgen receptor (AR) dependent and independent pathways which promote development of hormone resistant prostate cancer. This review will focus on modifications to the AR and associated pathways. Molecular modifications to the androgen receptor itself, e.g. mutations and/or amplification, although involved in the development of hormone resistance cannot explain all cases. Phosphorylation of AR, via either Ras/MAP kinase or PI3K/Akt signal transduction pathways, have been shown to activate AR in both a ligand (androgen) dependent and independent fashion. During this review we will discuss the clinical evidence to support AR dependent pathways as mediators of hormone resistance