A calculus for bordered Floer homology

We consider a class of manifolds with torus boundary admitting bordered Heegaard Floer homology of a particularly simple form, namely, the type D structure may be described graphically by a disjoint union of loops. We develop a calculus for studying bordered invariants of this form and, in particular, provide a complete description of slopes giving rise to L-space Dehn fillings as well as necessary and sufficient conditions for L-spaces resulting from identifying two such manifolds along their boundaries. As an application, we show that Seifert fibered spaces with torus boundary fall into this class, leading to a proof that, among graph manifolds containing a single JSJ torus, the property of being an L-space is equivalent to non-left-orderability of the fundamental group and to the non-existence of a coorientable taut foliation.Comment: 79 pages, 14 figures, uses tik

High concentration of 28,30-bisnorhopane and 25,28,30-trisnorhopane at the PETM in the Faroe-Shetland basin

Petroleum exploration in the Faroe-Shetland basin has resulted in the drilling of wells some of which contain expanded sections across the Palaeocene Eocene thermal maximum event (PETM). Here we present data from a Faroe – Shetland Basin well. Samples analysed have a mixture of terrestrial and marine inputs. PETM events, are recorded in both bulk and compound specific carbon isotope excursions of 2-3'. In addition, the PETM is marked by a change in palynology and we have observed changes in the distribution of biomarkers across the PETM and recognise a sharply defined spike in 25,28,30- trisnorhopane (TNH) and 28,30-bisnorhopane (BNH) concentrations at the PETM boundary. Firstly, while we have been able to identify variation in a range of compounds present in the core, their variation reassuringly mostly follow associated palynological changes. Demethylated hopanes 28,30-bisnorhopane (BNH) and 25,28,30-trisnorhopane (TNH), are present in relatively low concentrations just below and above the carbon isotope excursion (CIE), but in high concentrations at the PETM (Fig 1). The actual bacteria responsible for TNH and BNH in geological samples has so far not been determined [1]. However, BNH and TNH are thought to be produced by chemoautotrophic bacteria, their presence in rocks which formed in inner neritic environments may indicate strong upwelling or perhaps ocean overturn. Extreme shallowing of the CCD is well documented at the PETM, but there has previously been no clear indicator for a potential ocean overturn, although this has previously been mentioned as a potential driver for the event. While this has been dismissed as a mechanism driving the PETM events because it was envisaged as a local basin overturn, and can not explain the global extent of the PETM [2], we propose that the presence of TNH and BNH indicates ocean overturn may have played a role in the PETM. While it may not explain the isotopically light carbon in its entirety, stratification and ocean overturn may be a consequence of high temperatures, since palynological evidence indicates very low salinity conditions in surface waters at the PETM

World city network research at a theoretical impasse::On the need to re-establish qualitative approaches to understanding agency in world city networks

From the late 1990s, the establishment of a new relational ‘turn’ in the study of world city connectedness in globalization has run parallel to the wider relational turn occurring in economic geography. Early work, built firmly upon a qualitative approach to the collection and analyses of new inter-city datasets, considered cities as being constituted by their relations with other cities. Subsequent research, however, would take a strong quantitative turn, best demonstrated through the articulation of the inter-locking world city network (ILWCN) ‘model’ for measuring relations between cities. In this paper, we develop a critique of research based around the ILWCN model, arguing that this ‘top down’ quantitative approach has now reached a theoretical impasse. To address this impasse, we argue for a move away from Structural approaches in which the firm is the main unit of analysis, towards qualitative approaches in which individual agency and practice are afforded greater importance

Direct Marketing of Specialty Crops by Producers: A Price-Comparison between Farmers' Markets and Grocery Stores

Oftentimes, prices at farmers' markets are much cheaper than those at grocery stores. However, little is known about the pricing relationship between farmers' markets and nearby grocery stores. Only by further analyzing this relationship can we gain a better understanding of these pricing trends. Although this trend is seemingly consistent, further research is necessary to test this assumption. Through the collection of prices at both locales, farmers' markets and grocery stores, producers as well as consumers will have access to current prices in both markets. In recent years, consumers are looking for local produce and are willing to pay for them as they are faced with increased grocery store prices, while producers are simultaneously seeking to increase their profit margins. This paper uses data that was collected over the course of one year while recording pricing trends from farmers' markets and nearby grocery stores. The survey also records demographic and operational data from individual producers and or vendors at those farmers' markets within the State of Florida. It is hypothesized that producers selling at farmers' markets are not receiving a price premium for their products and the current prices they charge are, on average, significantly less than those found at a grocery store. Research gives evidence that producers should be receiving a price premium for their products. It is believed that they are being paid only a portion of the true market value for their products. As a result of this research, farmers should have a better understanding of state-wide pricing trends at farmers' markets and grocery stores which in turn will help them make better, more informed decisions when pricing and marketing their specialty crops.farmers markets, pricing, grocery stores, Agribusiness, Community/Rural/Urban Development, Farm Management, Marketing,

The minim-istic imagination : Scribal invention and the word in the early English alliterative tradition

I would like, however, to demonstrate in this essay--by looking specifically at the English alliterative tradition--that, in fact, the tension between oral and literate signification remains alive far into the so-called "literate" era. I will suggest that some vestiges of oral-derived rhetoric do not merely decay in the Middle English period; rather they become subject to the complex processes of amalgamation, transformation, and even reinvention.Not

Effects of Dam Removal on Assemblage Composition and the Interactions of Fishes in the Penobscot River, Maine

Dams and their impoundments disrupt river habitat connectivity to the detriment of migratory fishes. Removal of dams improves riverine connectivity and lotic habitat which benefits these fishes along with resident fluvial specialist species. Restoration efforts on the Penobscot River (Maine, USA) are among the largest recently completed in the United States, and include the removal of the two lower-most dams and improvements to fish passage at several remaining barriers. Here we describe initial and potential future changes to fish communities in the Penobscot River associated with these restoration efforts. We assessed fish assemblages in the mainstem river and several major tributaries before (2010-2012) and after dam removal (2014-2016) using boat electrofishing surveys and a stratified-random sampling design. In total, we sampled 303 km of shoreline and captured 107,335 individual fish from 39 species. Similarity indices suggest that the most pronounced changes in fish assemblage composition occurred in reaches that underwent both habitat and connectivity changes (i.e. directly above removed dams). The newly connected reaches became more compositionally similar, as demonstrated by an average increase of 31% in similarity scores. The similarity score changes in these reaches were driven by increasing access for anadromous fish and decreasing abundances of slow-water specialist species. For example, we observed a marked reduction in lacustrine species in former impoundments. We also found all anadromous species in greatest abundance below lower-most dam during each respective sampling period. River herrings Alosa spp. passed through the new fish elevator at the new lower-most dam and spawned in newly available habitat upstream, as evidenced by presence of juveniles in our samples. Our results demonstrate the potential for large dam removal projects to restore both fluvial and anadromous fish assemblages. We also examined the current and future impacts of rebounding river herring populations on Smallmouth Bass. Here we describe the diet and growth of Smallmouth Bass collected from different areas of the Penobscot River watershed and project changes to annual growth associated with increasing access to juvenile river herring prey using bioenergetics modeling. We collected 765 Smallmouth Bass throughout 2015, examined the stomach contents of 573 individuals, and found notable differences in diet between river reaches with common seasonal trends. Juvenile river herring composed an average of 19% (SE = ±6%) of stomach contents by mass from Smallmouth Bass collected in the freshwater tidal area but were observed only rarely in the diets upstream. We used von Bertalanffy growth models to examine potential difference in growth among reaches and found overlapping 95% credible intervals for all estimated growth parameters in each area, with the exception of the freshwater tidal reach where the average asymptotic length was the largest (425 mm TL). Results from bioenergetics models suggest that increasing consumption of juvenile river herring will likely lead to increases in seasonal growth throughout the watershed as river herring populations continue to rebound. Our results provide new insight to both the predator-prey dynamic of these fish in a large river and the implications of anadromous river herring population recovery in systems where Smallmouth Bass has been introduced

L-spaces, taut foliations, and graph manifolds

If $Y$ is a closed orientable graph manifold, we show that $Y$ admits a coorientable taut foliation if and only if $Y$ is not an L-space. Combined with previous work of Boyer and Clay, this implies that $Y$ is an L-space if and only if $\pi_1(Y)$ is not left-orderable.Comment: 10 pages, 1 figure; version 3 is accepted version, to appear in Compositio Mathematic