We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure coreplatform@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The United States has an abundance of shale plays and unconventional oil and gas drilling now occurs in over 30 states. Major development has occurred in North Dakota, Texas, Louisiana, Arkansas, Michigan, Oklahoma, Wyoming, Colorado, Pennsylvania, Ohio, and West Virginia. The technological advances included the combination of horizontal drilling and hydraulic fracturing, new slick water formulations, and improvements in drilling technologies and fracking design such as “zipper fracking”. The upstream sector includes pre-drilling activities, pad preparation, drilling, hydraulic fracturing, and completion. The midstream sector includes pipeline construction and maintenance and processing facilities that separate the products of mixed gas. These processing facilities can be quite extensive, especially in Southwestern Pennsylvania, Eastern Ohio, and the panhandle of West Virginia where wet gas predominates. This review presents an overview of unconventional gas extraction in the Appalachian Basin as currently practiced in Pennsylvania, Ohio, and West Virginia.
The Energy Information Administration (EIA) has assessed 46 countries for their technically recoverable unconventional oil and gas reserves. They estimate the global shale gas reserves at 7,577 Tcf (trillion cubic feet) and the global shale oil reserves at 419 billion bbl (barrels). The 10 largest reserves for shale gas are in China, Argentina, Algeria, United States, Canada, Mexico, Australia, South Africa, Russia, and Brazil. The European Union also has significant deposits with the majority located in Poland and France. The 10 largest reserves for shale oil are in the United States, Russia, China, Argentina, Libya, United Arab Emirates, Chad, Australia, Venezuela, and Mexico. To date, only the United States and Canada have reached commercial level production for shale gas and oil, followed to a lesser extent by China and Argentina. Australia has seen its efforts concentrate on liquified natural gas (LNG) and export. Most other countries remain in the exploratory phase or have halted development. This chapter provides a brief review of the major shale gas and oil plays based on the extensive assessment done by the EIA, and the current status of their development.
The development of unconventional oil and gas shales using hydraulic fracturing and directional drilling is currently a focal point of energy and climate change discussions. While this technology has provided access to substantial reserves of oil and gas, the need for large quantities of water, emissions, and infrastructure raises concerns over the environmental impacts. Written by an international consortium of experts, this book provides a comprehensive overview of the extraction from unconventional reservoirs, providing clear explanations of the technology and processes involved. Each chapter is devoted to different aspects including global reserves, the status of their development and regulatory framework, water management and contamination, air quality, earthquakes, radioactivity, isotope geochemistry, microbiology, and climate change. Case studies present baseline studies, water monitoring efforts and habitat destruction. This book is accessible to a wide audience, from academics to industry professionals and policy makers interested in environmental pollution and petroleum exploration.
In May of 2018, PulseNet, the national molecular subtyping network for enteric pathogens, detected a multistate cluster of illnesses caused by an uncommon molecular subtype of Salmonella serovar Mbandaka. A case was defined as an illness in a person infected with the outbreak strain of Salmonella Mbandaka with illness onset on or after 3 March 2018 and before 1 September 2018. One-hundred thirty-six cases from 36 states were identified; 35 hospitalisations and no deaths were reported. Ill people ranged in age from <1 year to 95 years (median: 57 years). When standardised questionnaires did not generate a strong hypothesis, opened-ended interviews were performed. Sixty-three of 84 (75%) ultimately reported consuming or possibly consuming a specific sweetened puffed wheat cereal in the week before illness onset. Environmental sampling performed at the cereal manufacturing facility yielded the outbreak strain. The outbreak strain was also isolated from open cereal samples from ill people's homes and from a sealed retail sample. Due to these findings, the brand owner of the product issued a voluntary recall of the cereal on 14 June 2018. Additional investigation of the manufacturing facility identified persistent environmental contamination with Salmonella Mbandaka that was closely genetically related to other isolates in the outbreak. This investigation highlights the ability of Salmonella to survive in low-moisture environments, and the potential for prolonged outbreaks linked to products with long shelf lives and large distribution areas.
An enduring interest in categories (katēgoriai),1 and in Aristotle’s Categories in particular, has led readers since antiquity to study the treatise which Porphyry entitled On the Genera of Being (6.1–3).2 Ancient and modern readers broadly agree that: (1) Plotinus understands his own subject matter to be ‘the kinds of things that exist’ (peri tōn genōn tou ontos); (2) the treatise displays the result of a deep and substantial engagement with Aristotle’s Categories; and (3) Plotinus raises important and substantive puzzles (aporiai) about what is said in the Categories.3 Beyond this, plausible interpretations diverge. On one view, Plotinus deploys the resources of earlier Platonist critics to challenge the Categories’ ontological prioritization of particular substance, especially as it is treated by earlier Aristotelian commentators.4 On an alternative reading, Plotinus ‘purifies’ Aristotelian ontology in order to sketch a new taxonomy of the sensible world, complementing his own account of the intelligible world and clearing a trail for Porphyry’s integration of Aristotle into a new Platonist curriculum.5
Hausel and Rodriguez-Villegas (2015, Astérisque 370, 113–156) recently observed that work of Göttsche, combined with a classical result of Erdös and Lehner on integer partitions, implies that the limiting Betti distribution for the Hilbert schemes
$(\mathbb {C}^{2})^{[n]}$
on
$n$
points, as
$n\rightarrow +\infty ,$
is a Gumbel distribution. In view of this example, they ask for further such Betti distributions. We answer this question for the quasihomogeneous Hilbert schemes
$((\mathbb {C}^{2})^{[n]})^{T_{\alpha ,\beta }}$
that are cut out by torus actions. We prove that their limiting distributions are also of Gumbel type. To obtain this result, we combine work of Buryak, Feigin, and Nakajima on these Hilbert schemes with our generalization of the result of Erdös and Lehner, which gives the distribution of the number of parts in partitions that are multiples of a fixed integer
$A\geq 2.$
Furthermore, if
$p_{k}(A;n)$
denotes the number of partitions of
$n$
with exactly
$k$
parts that are multiples of
$A$
, then we obtain the asymptotic
Catatonia, a severe neuropsychiatric syndrome, has few studies of sufficient scale to clarify its epidemiology or pathophysiology. We aimed to characterise demographic associations, peripheral inflammatory markers and outcome of catatonia.
Methods
Electronic healthcare records were searched for validated clinical diagnoses of catatonia. In a case–control study, demographics and inflammatory markers were compared in psychiatric inpatients with and without catatonia. In a cohort study, the two groups were compared in terms of their duration of admission and mortality.
Results
We identified 1456 patients with catatonia (of whom 25.1% had two or more episodes) and 24 956 psychiatric inpatients without catatonia. Incidence was 10.6 episodes of catatonia per 100 000 person-years. Patients with and without catatonia were similar in sex, younger and more likely to be of Black ethnicity. Serum iron was reduced in patients with catatonia [11.6 v. 14.2 μmol/L, odds ratio (OR) 0.65 (95% confidence interval (CI) 0.45–0.95), p = 0.03] and creatine kinase was raised [2545 v. 459 IU/L, OR 1.53 (95% CI 1.29–1.81), p < 0.001], but there was no difference in C-reactive protein or white cell count. N-Methyl-d-aspartate receptor antibodies were significantly associated with catatonia, but there were small numbers of positive results. Duration of hospitalisation was greater in the catatonia group (median: 43 v. 25 days), but there was no difference in mortality after adjustment.
Conclusions
In the largest clinical study of catatonia, we found catatonia occurred in approximately 1 per 10 000 person-years. Evidence for a proinflammatory state was mixed. Catatonia was associated with prolonged inpatient admission but not with increased mortality.
The definition of combined approaches is broad. This can include multiple portals to the same or different region in the skull base. The “pull-through technique is a versatile, dual-keyhole approach developed to attach tumors that extend between the temporal and occipital poles. This approach is complex, as it entails a knowledge of the intricate anatomy and eloquent cortical and subcortical structures in this region. This combined approach is tailed to minimize peripheral brain damage while providing a direct route to the pathology. This chapter discusses the indications, the anatomy, the patient selection, and the surgical nuances of this approach.