Deep-sea nematodes (Comesomatidae) from the Southwest Pacific Ocean: five new species and three new species records

The present study describes five new free-living nematode species and provides three new species records of the family Comesomatidae (genera Cervonema Wieser, 1954, Dorylaimopsis Ditlevsen, 1918, Hopperia Vitiello, 1969, and Kenyanema Muthumbi et al., 1997) from the continental margin of New Zealand, Southwest Pacific. Dichotomous identification keys are provided for all known species of Dorylaimopsis and Hopperia. Cervonema shiae Chen & Vincx, 2000 is recorded for the first time outside the type locality (Beagle Channel, Chile). C. kaikouraensis sp. nov. is characterised by amphideal fovea with 5.5 turns situated at 1.7 head diameter from anterior end, jointed outer labial setae, equal in length to cephalic setae, sperm dimorphism, and 5-6 small pre-cloacal supplements. C. multispira sp. nov. is characterised by amphideal fovea with 8.0-8.5 turns situated at 2.6-4.0 head diameter from anterior end, cephalic setae 2-3 μm long, slightly shorter than outer labial setae, presence of six uninucleated cells in males (potentially pseudocoelomocytes or supplementary excretory cells), 5 small pre-cloacal supplements, and strongly cuticularised, arcuate spicules with capitulum. C. proberti sp. nov. is characterised by amphideal fovea with 5 turns and located at < 1 head diameter from anterior end, cephalic setae 1.6-2.0 times longer than outer labial setae, and 8 small pre-cloacal supplements. Dorylaimopsis nodderi sp. nov. is characterised by cuticle with lateral differentiation consisting of three longitudinal rows of larger dots in the pharyngeal and caudal regions, two rows of larger dots in middle region of body, and spicules with rounded ventral projection at one third of spicule length from distal end, giving appearance of a joint. Hopperia ancora sp. nov. is characterised by short conical cephalic setae, spicules with hook-like projection at distal end, gubernaculum with bent apophyses, and 11-13 pre-cloacal supplements. H. beaglense Chen & Vincx, 1998 is recorded from Kaikoura Canyon, the fi rst record of this species outside the type locality (Beagle Channel, Chile). Kenyanema monorchis Muthumbi et al., 1997 is also recorded for the first time outside the type locality (Indian Ocean)

Crop weather models of barley and spring wheat yield for agrophysical units in North Dakota

Models based on multiple regression were developed to estimate barley yield and spring wheat yield from weather data for Agrophysical units(APU) in North Dakota. The predictor variables are derived from monthly average temperature and monthly total precipitation data at meteorological stations in the cooperative network. The models are similar in form to the previous models developed for Crop Reporting Districts (CRD). The trends and derived variables were the same and the approach to select the significant predictors was similar to that used in developing the CRD models. The APU models show sight improvements in some of the statistics of the models, e.g., explained variation. These models are to be independently evaluated and compared to the previously evaluated CRD models. The comparison will indicate the preferred model area for this application, i.e., APU or CRD

Deficit-financed tax cuts and interest rates

Why do proposals to lower taxes often meet with opposition in Congress. One argument is that lowering taxes without an equivalent fall in government spending may lead to future budget deficits, which will translate into higher long-term interest rates and a lower level of income. Sylvain Leduc discusses the theoretical arguments under which budget deficits lead to higher interest rates. He also surveys empirical studies that used data on expected budget deficits to document the possibility that increases in future budget deficits are associated with higher real long-term interest rates.Deficit financing ; Taxation ; Interest rates

How inflation hawks escape expectations traps

Why did inflation increase so dramatically from the 1960s to the 1970s? One possible theory is that once people started believing inflation would rise, the Fed was forced to validate those expectations by increasing the money supply. In "How Inflation Hawks Escape Expectations Traps," Sylvain Leduc discusses this "expectations trap" hypothesis and uses a direct measure of expectations to see if the theory is consistent with the data.Inflation (Finance)

Combined Intra- and Inter-domain Traffic Engineering using Hot-Potato Aware Link Weights Optimization

A well-known approach to intradomain traffic engineering consists in finding the set of link weights that minimizes a network-wide objective function for a given intradomain traffic matrix. This approach is inadequate because it ignores a potential impact on interdomain routing. Indeed, the resulting set of link weights may trigger BGP to change the BGP next hop for some destination prefixes, to enforce hot-potato routing policies. In turn, this results in changes in the intradomain traffic matrix that have not been anticipated by the link weights optimizer, possibly leading to degraded network performance. We propose a BGP-aware link weights optimization method that takes these effects into account, and even turns them into an advantage. This method uses the interdomain traffic matrix and other available BGP data, to extend the intradomain topology with external virtual nodes and links, on which all the well-tuned heuristics of a classical link weights optimizer can be applied. A key innovative asset of our method is its ability to also optimize the traffic on the interdomain peering links. We show, using an operational network as a case study, that our approach does so efficiently at almost no extra computational cost.Comment: 12 pages, Short version to be published in ACM SIGMETRICS 2008, International Conference on Measurement and Modeling of Computer Systems, June 2-6, 2008, Annapolis, Maryland, US

Generalised Nonblocking

This paper studies the nonblocking check used in supervisory control of discrete event systems and its limitations. Different examples with different liveness requirements are discussed. It is shown that the standard nonblocking check can be used to specify most requirements of interest, but that it lacks expressive power in a few cases. A generalised nonblocking check is proposed to overcome the weakness, and its relationship to standard nonblocking is explored. Results suggest that generalised nonblocking, while having the same useful properties with respect to synthesis and compositional verification, can provide for more concise problem representations in some cases

Compositional nonblocking verificationusing generalised nonblocking abstractions

This paper proposes a method for compositional verification of the standard and generalized nonblocking properties of large discrete event systems. The method is efficient as it avoids the explicit construction of the complete state space by considering and simplifying individual subsystems before they are composed further. Simplification is done using a set of abstraction rules preserving generalized nonblocking equivalence, which are shown to be correct and computationally feasible. Experimental results demonstrate the suitability of the method to verify several large-scale discrete event systems models both for standard and generalized nonblocking

Incentivizing Resilience in Financial Networks

When banks extend loans to each other, they generate a negative externality in the form of systemic risk. They create a network of interbank exposures by which they expose other banks to potential insolvency cascades. In this paper, we show how a regulator can use information about the financial network to devise a transaction-specific tax based on a network centrality measure that captures systemic importance. Since different transactions have different impact on creating systemic risk, they are taxed differently. We call this tax a Systemic Risk Tax (SRT). We use an equilibrium concept inspired by the matching markets literature to show analytically that this SRT induces a unique equilibrium matching of lenders and borrowers that is systemic-risk efficient, i.e. it minimizes systemic risk given a certain transaction volume. On the other hand, we show that without this SRT multiple equilibrium matchings exist, which are generally inefficient. This allows the regulator to effectively stimulate a `rewiring' of the equilibrium interbank network so as to make it more resilient to insolvency cascades, without sacrificing transaction volume. Moreover, we show that a standard financial transaction tax (e.g. a Tobin-like tax) has no impact on reshaping the equilibrium financial network because it taxes all transactions indiscriminately. A Tobin-like tax is indeed shown to have a limited effect on reducing systemic risk while it decreases transaction volume.Comment: 38 pages, 9 figure

Two new genera and five new species of Selachinematidae (Nematoda, Chromadorida) from the continental slope of New Zealand

Two new genera and five new species of Selachinematidae are described from the New Zealand upper continental slope (350-1240 m depth). Synonchiella rotundicauda sp. nov. is characterised by cephalic setae 0.25 cbd long, mandibles each with two pairs of hooks and two wing-like projections laterally, eight cup-shaped pre-cloacal supplements and short rounded tail. Pseudocheironchus gen. nov. is similar to Cheironchus, but differs from the latter in having a cuticle without lateral differentiation, cephalic setae only slightly longer than the outer labial sensillae, and a posterior buccal cavity with three equal mandibles. Pseudocheironchus ingluviosus gen. et sp. nov. is characterised by mandibles with eight blunt teeth, multispiral amphideal fovea with five turns, and a short rounded tail. Males of this new species with 17-19 cup-shaped pre-cloacal supplements. Males of the genus Cobbionema are described for the first time; C. trigamma sp. nov. is characterised by four long cephalic setae and six smaller outer labial setae in one circle, six rhabdions surrounding the anterior buccal cavity, each with two pairs of pointed projections at their posterior extremities, posterior buccal cavity widening posteriorly, with three pairs of rhabdions fused posteriorly and widening anteriorly, males with two testes pointing anteriorly and with reflexed posterior testis, and no pre-cloacal supplements. Gammanema agglutinans sp. nov. is characterised by a short, stout body often covered in adhering mucus and detritus, cuticle with minute spines, leaf-shaped somatic setae with ducts, sexual dimorphism in the shape of the amphideal fovea (loop-shaped in males and spiral in females), posterior buccal cavity with three pairs of broad, column-shaped rhabdions fused anteriorly, intestine cells with orange-brown granules, and small tubular pre-cloacal supplements. Bendiella gen. nov. is most similar to Halichoanolaimus, but differs from the latter, and all other genera of the family Selachinematidae, in having a cuticle with lateral differentiation consisting of longitudinal rows of larger dots, and from all other genera of the Choniolaiminae in lacking pre-cloacal supplements. Bendiella thalassa gen. et sp. nov. is characterised by amphideal fovea with 5.25 turns, anterior buccal cavity with twelve rhabdions, each with a pair of pointed projections at posterior extremity, posterior buccal cavity with three Y-shaped pairs of slender rhabdions fused from two thirds of distance from anterior ends, and conico-cylindrical tail