Measuring Liquidity in Gas Markets: The Case of the UK National Balancing Point. ESRI Research Bulletin 2019/06

Liquidity is the ability to match buyers and sellers at the lowest transaction costs. Therefore, in a liquid market, executing a transaction over a short-time horizon does not imply higher costs than spreading the same transaction over a longer horizon. Policymakers and practitioners traditionally use the churn ratio to measure liquidity in gas markets. The churn ratio is the ratio of traded volume to actual physical delivery. However, this measure does not consider the impact of trading activity on prices. This research focuses on applying different measures of liquidity, which are used in financial markets, to measure and assess the impact of trading activity on prices. The UK National Balancing Point (NBP) is used as a case study, since it is the most mature hub for gas trading in Europe. Therefore, conclusions from this study can be extended to other gas markets. The research shows that a positive correlation exists between trading activity and prices in the market. However, the strength of this correlation changes over time, depending upon market conditions. Specifically, in the presence of oversupply the impact of trading activity on prices is lower, thus implying that trading a high amount of gas is less expensive, and liquidity is high. Consequently, risk management costs are also less expensive

The responses of small and large firms to tight credit shocks : the case of 2008 through the lens of Gertler and Gilchrist (1994)

Do large firms and small firms behave differently when credit becomes more costly or harder to obtain? Past research has found that small firms are more likely to be credit-constrained and thus tend to be affected more negatively than large firms during such times. Recent findings from the 2007-2009 recession, however, raise questions about the roles of small and large firms during periods of tight creditBusiness cycles ; Recessions

Electron Cotunneling into a Kondo Lattice

Motivated by recent experimental interest in tunneling into heavy electron materials, we present a theory for electron tunneling into a Kondo lattice. The passage of an electron into the Kondo lattice is accompanied by a simultaneous spin flip of the localized moments via cotunneling mechanism. We compute the tunneling current with the large-$N$ mean field theory. In the absence of disorder, differential tunneling conductance exhibits two peaks separated by the hybridization gap. Disorder effects lead to the smearing of the gap resulting in a Fano lineshape.Comment: 4 pages, 2 eps figure

The Discovery of Trissolcus japonicus (Hymenoptera: Scelionidae) in Michigan

The invasive brown marmorated stink bug, Halyomorpha halys (Stål), is a pest of growing economic importance in the United States, the control of which currently relies on pesticide applications. Biological control could provide sustainable and long-term control but classical biological control agents have not yet been approved. Adventive populations of a potential biological control agents, the Samurai wasp, Trissolcus japonicus (Ashmead), have been found in the United States, first in Maryland in 2014, expanding its range west to Ohio by 2017. Trissolcus japonicus is a highly effective parasitoid of H. halys eggs, but its redistribution and augmentative releases are restricted to states where it has been detected in the wild. To assess the presence of T. japonicus in Michigan and attack rates of H. halys by native natural enemies we deployed 189 H. halys egg masses at ten sites in lower Michigan between May and October in 2018. In addition, we deployed 51 native stink bug egg masses at the same sites to evaluate potential non-target effects of T. japonicus in the field, which were shown to occur in laboratory studies. We found T. japonicus in a single H. halys egg mass, which constitutes the first record of this Asian parasitoid in Michigan. Native predators and parasitoids caused minimal mortality of H. halys eggs and we did not find evidence of non-target effects of T. japonicus on native stink bug species. These findings open the door to initiation of a classical biological control program using an efficient, coevolved parasitoid from the native range of H. halys

Can Frustration Preserve a Quasi-Two-Dimensional Spin Fluid?

Using spin-wave theory, we show that geometric frustration fails to preserve a two-dimensional spin fluid. Even though frustration can remove the interlayer coupling in the ground-state of a classical anti-ferromagnet, spin layers innevitably develop a quantum-mechanical coupling via the mechanism of ``order from disorder''. We show how the order from disorder coupling mechanism can be viewed as a result of magnon pair tunneling, a process closely analogous to pair tunneling in the Josephson effect. In the spin system, the Josephson coupling manifests itself as a a biquadratic spin coupling between layers, and for quantum spins, these coupling terms are as large as the inplane coupling. An alternative mechanism for decoupling spin layers occurs in classical XY models in which decoupled "sliding phases" of spin fluid can form in certain finely tuned conditions. Unfortunately, these finely tuned situations appear equally susceptible to the strong-coupling effects of quantum tunneling, forcing us to conclude that in general, geometric frustration cannot preserve a two-dimensional spin fluid.Comment: 12 pages, 3 figure

Large scale crystallization of protein pharmaceuticals in microgravity via temperature change

The major objective of this research effort is the temperature driven growth of protein crystals in large batches in the microgravity environment of space. Pharmaceutical houses are developing protein products for patient care, for example, human insulin, human growth hormone, interferons, and tissue plasminogen activator or TPA, the clot buster for heart attack victims. Except for insulin, these are very high value products; they are extremely potent in small quantities and have a great value per gram of material. It is feasible that microgravity crystallization can be a cost recoverable, economically sound final processing step in their manufacture. Large scale protein crystal growth in microgravity has significant advantages from the basic science and the applied science standpoints. Crystal growth can proceed unhindered due to lack of surface effects. Dynamic control is possible and relatively easy. The method has the potential to yield large quantities of pure crystalline product. Crystallization is a time honored procedure for purifying organic materials and microgravity crystallization could be the final step to remove trace impurities from high value protein pharmaceuticals. In addition, microgravity grown crystals could be the final formulation for those medicines that need to be administered in a timed release fashion. Long lasting insulin, insulin lente, is such a product. Also crystalline protein pharmaceuticals are more stable for long-term storage. Temperature, as the initiation step, has certain advantages. Again, dynamic control of the crystallization process is possible and easy. A temperature step is non-invasive and is the most subtle way to control protein solubility and therefore crystallization. Seeding is not necessary. Changes in protein and precipitant concentrations and pH are not necessary. Finally, this method represents a new way to crystallize proteins in space that takes advantage of the unique microgravity environment. The results from two flights showed that the hardware performed perfectly, many crystals were produced, and they were much larger than their ground grown controls. Morphometric analysis was done on over 4,000 crystals to establish crystal size, size distribution, and relative size. Space grown crystals were remarkably larger than their earth grown counterparts and crystal size was a function of PCF volume. That size distribution for the space grown crystals was a function of PCF volume may indicate that ultimate size was a function of temperature gradient. Since the insulin protein concentration was very low, 0.4 mg/ml, the size distribution could also be following the total amount of protein in each of the PCF's. X-ray analysis showed that the bigger space grown insulin crystals diffracted to higher resolution than their ground grown controls. When the data were normalized for size, they still indicated that the space crystals were better than the ground crystals

Modelling foraging movements of diving predators : A theoretical study exploring the effect of heterogeneous landscapes on foraging efficiency

Peer reviewedPublisher PD

Framing COVID-19: How we conceptualize and discuss the pandemic on Twitter

Doctors and nurses in these weeks are busy in the trenches, fighting against a new invisible enemy: Covid-19. Cities are locked down and civilians are besieged in their own homes, to prevent the spreading of the virus. War-related terminology is commonly used to frame the discourse around epidemics and diseases. Arguably the discourse around the current epidemic will make use of war-related metaphors too,not only in public discourse and the media, but also in the tweets written by non-experts of mass communication. We hereby present an analysis of the discourse around #Covid-19, based on a corpus of 200k tweets posted on Twitter during March and April 2020. Using topic modelling we first analyze the topics around which the discourse can be classified. Then, we show that the WAR framing is used to talk about specific topics, such as the virus treatment, but not others, such as the effects of social distancing on the population. We then measure and compare the popularity of the WAR frame to three alternative figurative frames (MONSTER, STORM and TSUNAMI) and a literal frame used as control (FAMILY). The results show that while the FAMILY literal frame covers a wider portion of the corpus, among the figurative framings WAR is the most frequently used, and thus arguably the most conventional one. However, we conclude, this frame is not apt to elaborate the discourse around many aspects involved in the current situation. Therefore, we conclude, in line with previous suggestions, a plethora of framing options, or a metaphor menu, may facilitate the communication of various aspects involved in the Covid-19-related discourse on the social media, and thus support civilians in the expression of their feelings, opinions and ideas during the current pandemic.Comment: 41 pages, 6 figure

Physiological Effects of Five Different Marine Natural Organic Matters (NOMs) and Three Different Metals (Cu, Pb, Zn) on Early Life Stages of the Blue Mussel (Mytilus galloprovincialis)

Metals are present in aquatic environments as a result of natural and anthropogenic inputs, and may induce toxicity to organisms. One of the main factors that influence this toxicity in fresh water is natural organic matter (NOM) but all NOMs are not the same in this regard. In sea water, possible protection by marine NOMs is not well understood. Thus, our study isolated marine NOMs by solid-phase extraction from five different sites and characterized them by excitation-emission fluorescence analysis—one inshore (terrigenous origin), two offshore (autochthonous origin), and two intermediate in composition (indicative of a mixed origin). The physiological effects of these five NOMS alone (at 8 mg/L), of three metals alone (copper, lead and zinc at 6 µg Cu/L, 20 µg Pb/L, and 25 µg Zn/L respectively), and of each metal in combination with each NOM, were evaluated in 48-h exposures of mussel larvae. Endpoints were whole body Ca2++Mg2+-ATPase activity, carbonic anhydrase activity and lipid peroxidation. By themselves, NOMs increased lipid peroxidation, Ca2++Mg2+-ATPase, and/or carbonic anhydrase activities (significant in seven of 15 NOM-endpoint combinations), whereas metals by themselves did not affect the first two endpoints, but Cu and Pb increased carbonic anhydrase activities. In combination, the effects of NOMs predominated, with the metal exerting no additional effect in 33 out of 45 combinations. While NOM effects varied amongst different isolates, there was no clear pattern with respect to optical or chemical properties. When NOMs were treated as a single source by data averaging, NOM had no effect on Ca2++Mg2+-ATPase activity but markedly stimulated carbonic anhydrase activity and lipid peroxidation, and there were no additional effects of any metal. Our results indicate that marine NOMs may have direct effects on this model marine organism, as well as protective effects against metal toxicity, and the quality of marine NOMs may be an important factor in these actions