The Darst Creek oil field, Guadalupe County, Texas

The Darst Green Oil Field, the fourth Edwards limestone field in southwest Texas, was discovered July 18, 1929, in eastern Guadalupe County (fig. 1). It is located along one of a series of "en échelon" faults parallel with, and southeast of, the fault zone of Texas. After migrating up-dip from the southeast, the oil in this field was trapped in the upper 50 feet of the porous Edwards limestone, which was faulted into juxtaposition with the impervious beds on the downthrown side of the fault. In addition to wells producing from the Edwards, several produce from fault plane cavities, and two supposedly are producing from reworked serpentine deposits. The maximum vertical displacement along the fault is calculated to be approximately 550 feet on top of the Austin chain. The surface beds in the area are middle and upper Indio sandy clays of lower Eocene age. Aside from fault planes, the structure is evidenced on the surface by steep dips, a decided down-dip swing in the Indio-Carrizo contact, and a repetition of upper Indio. The productive area of the field, including the Appling area to the northeast, consists of approximately 1670 acres. It is 6 miles in length and in places exceeds 4000 feet in width. Of the 291 wells drilled in the area, only 19 are dry holes. The total production through December 1931, was 19,700,340 barrels. The oil has a paraffin base, a deep green color, and a specific gravity of 36° Baumé. As proration has been in effect since the field was discovered, the development has been very slow. This, however, has proved beneficial by delaying the encroachment of sulphur water and tending to increase the ultimate recovery of oil.Geological Science

Optical addressing of an individual erbium ion in silicon

The detection of electron spins associated with single defects in solids is a critical operation for a range of quantum information and measurement applications currently under development. To date, it has only been accomplished for two centres in crystalline solids: phosphorus in silicon using electrical readout based on a single electron transistor (SET) and nitrogen-vacancy centres in diamond using optical readout. A spin readout fidelity of about 90% has been demonstrated with both electrical readout and optical readout, however, the thermal limitations of the electrical readout and the poor photon collection efficiency of the optical readout hinder achieving the high fidelity required for quantum information applications. Here we demonstrate a hybrid approach using optical excitation to change the charge state of the defect centre in a silicon-based SET, conditional on its spin state, and then detecting this change electrically. The optical frequency addressing in high spectral resolution conquers the thermal broadening limitation of the previous electrical readout and charge sensing avoids the difficulties of efficient photon collection. This is done with erbium in silicon and has the potential to enable new architectures for quantum information processing devices and to dramatically increase the range of defect centres that can be exploited. Further, the efficient electrical detection of the optical excitation of single sites in silicon is a major step in developing an interconnect between silicon and optical based quantum computing technologies.Comment: Corrected the third affiliation. Corrected one cross-reference of "Fig. 3b" to "Fig. 3c". Corrected the caption of Fig. 3a by changing (+-)1 to

Short-period variability in the Class II methanol maser source G12.89+0.49 (IRAS 18089-1732)

Time series are presented for the class II methanol maser source G12.89+0.49, which has been monitored for nine years at the Hartebeesthoek Radio Astronomy Observatory. The 12.2 and 6.7 GHz methanol masers were seen to exhibit rapid, correlated variations on timescales of less than a month. Daily monitoring has revealed that the variations have a periodic component with a period of 29.5 days. The period seems to be stable over the 110 cycles spanned by the time series. There are variations from cycle to cycle, with the peak of the flare occurring anywhere within an eleven day window but the minima occur at the same phase of the cycle. Time delays of up to 5.7 days are seen between spectral features at 6.7 GHz and a delay of 1.1 day is seen between the dominant 12.2 GHz spectral feature and its 6.7 GHz counterpart.Comment: Accepted by MNRAS. 18 pages, 20 figure

How important is the credit channel? An empirical study of the US banking crisis

We examine whether by adding a credit channel to the standard New Keynesian model we can account better for the behaviour of US macroeconomic data up to and including the banking crisis. We use the method of indirect inference which evaluates statistically how far a model's simulated behaviour mimics the behaviour of the data. We find that the model with credit dominates the standard model by a substantial margin. Credit shocks are the main contributor to the variation in the output gap during the crisis

Low temperature heat capacity of Fe_{1-x}Ga_{x} alloys with large magneostriction

The low temperature heat capacity C_{p} of Fe_{1-x}Ga_{x} alloys with large magnetostriction has been investigated. The data were analyzed in the standard way using electron ($\gamma T$) and phonon ($\beta T^{3}$) contributions. The Debye temperature $\Theta_{D}$ decreases approximately linearly with increasing Ga concentration, consistent with previous resonant ultrasound measurements and measured phonon dispersion curves. Calculations of $\Theta_{D}$ from lattice dynamical models and from measured elastic constants C_{11}, C_{12} and C_{44} are in agreement with the measured data. The linear coefficient of electronic specific heat $\gamma$ remains relatively constant as the Ga concentration increases, despite the fact that the magnetoelastic coupling increases. Band structure calculations show that this is due to the compensation of majority and minority spin states at the Fermi level.Comment: 14 pages, 6 figure

To Lose Both Would Look Like Carelessness: Tasmanian Devil Facial Tumour Disease

How can you manage an emerging disease threat--in this case, Tasmanian devil facial tumor disease--that poses a serious conservation threat, when so little is known about the disease

A Property Law Reader: Cases, Questions and Commentary, 4th Edition, Preface and Table of Contents

Property law — that body of rules which describes and defines relationships between people with respect to things — involves many choices. The choices include determining when it is appropriate and desirable to label something as property or, more accurately, as subject to a relationship between people based in the rules of property law. The choices involve asking questions, including why it is that we create relationships based in property and who should benefit from them. The rules of property law are notoriously difficult and complex, and they frequently appear disjointed and unconnected, but they are not arbitrary. They are based on choices, sometimes made explicitly, other times implicitly, about what is important. One of our principal goals in this collection of property law materials is to emphasize that the making of choices is a necessary, although commonly under-acknowledged, element in creating a regime of property law. We have made a choice to highlight what Margaret Davies has described as ‘‘asking the why question”. This involves using materials that prompt not only an investigation of the rules of property law but also the justifications for those rules. Another choice we have made in compiling this material is to highlight the disparate sources of property law. Excerpts from the decisions of common law courts dominate the page count, and learning to derive the principles and the rules from these decisions is a core element in a common law legal education, but there is much else besides. We have chosen to emphasize Indigenous legal traditions as one of the sources of Canadian property law alongside the civil law tradition in Quebec and the common law tradition (including principles of equity) in the rest of the country. This presents challenges, not the least because the concept or category of property, as it has developed in western legal traditions, sits uneasily with many Indigenous legal traditions. But it is also a useful reminder that the rules governing human relationships with respect to things are not only jurisdictionally, but also culturally and historically specific. The law of property is also to be found in a great diversity of legislative instruments, ranging from city by-laws, through provincial and federal statutes and regulations, to international agreements. These sources are scattered throughout the volume, but using them presents other challenges. Within the Canadian federation, property is primarily a matter of provincial jurisdiction, and the diversity of property regimes among the provinces limits our capacity to delve into the particular statutory framework of any one jurisdiction when producing a set of materials that is relevant across Canadian common law jurisdictions. As a result, we include examples from different jurisdictions and leave it to course instructors to add as much or as little of what is particular to their jurisdictions as they think desirable

Identification of Rare Causal Variants in Sequence-Based Studies: Methods and Applications to VPS13B, a Gene Involved in Cohen Syndrome and Autism

Pinpointing the small number of causal variants among the abundant naturally occurring genetic variation is a difficult challenge, but a crucial one for understanding precise molecular mechanisms of disease and follow-up functional studies. We propose and investigate two complementary statistical approaches for identification of rare causal variants in sequencing studies: a backward elimination procedure based on groupwise association tests, and a hierarchical approach that can integrate sequencing data with diverse functional and evolutionary conservation annotations for individual variants. Using simulations, we show that incorporation of multiple bioinformatic predictors of deleteriousness, such as PolyPhen-2, SIFT and GERP++ scores, can improve the power to discover truly causal variants. As proof of principle, we apply the proposed methods to VPS13B, a gene mutated in the rare neurodevelopmental disorder called Cohen syndrome, and recently reported with recessive variants in autism. We identify a small set of promising candidates for causal variants, including two loss-of-function variants and a rare, homozygous probably-damaging variant that could contribute to autism risk