670 research outputs found
First-Class Subtypes
First class type equalities, in the form of generalized algebraic data types
(GADTs), are commonly found in functional programs. However, first-class
representations of other relations between types, such as subtyping, are not
yet directly supported in most functional programming languages.
We present several encodings of first-class subtypes using existing features
of the OCaml language (made more convenient by the proposed modular implicits
extension), show that any such encodings are interconvertible, and illustrate
the utility of the encodings with several examples.Comment: In Proceedings ML 2017, arXiv:1905.0590
The Only Undoable CRDTs are Counters
In comparing well-known CRDTs representing sets that can grow and shrink, we
find caveats. In one, the removal of an element cannot be reliably undone. In
another, undesirable states are attainable, such as when an element is present
-1 times (and so must be added for the set to become empty). The first lacks a
general-purpose undo, while the second acts less like a set and more like a
tuple of counters, one per possible element.
Using some group theory, we show that this trade-off is unavoidable: every
undoable CRDT is a tuple of counters
Recommended from our members
Current Knowledge and Future Directions in Developing Strategies to Combat Pseudomonas aeruginosa Infection.
In the face of growing antimicrobial resistance, there is an urgent need for the development of effective strategies to target Pseudomonas aeruginosa. This metabolically versatile bacterium can cause a wide range of severe opportunistic infections in patients with serious underlying medical conditions, such as those with burns, surgical wounds or people with cystic fibrosis. Many of the key adaptations that arise in this organism during infection are centered on core metabolism and virulence factor synthesis. Interfering with these processes may provide a new strategy to combat infection which could be combined with conventional antibiotics. This review will provide an overview of the most recent work that has advanced our understanding of P. aeruginosa infection. Strategies that exploit this recent knowledge to combat infection will be highlighted alongside potential alternative therapeutic options and their limitations.Herchel Smith Postdoctoral Fellowshi
Treatment of flux shape uncertainties in unfolded, flux-averaged neutrino cross-section measurements
The exact way of treating flux shape uncertainties in unfolded, flux-averaged
neutrino cross-section measurements can lead to subtle issues when comparing
the results to model predictions. There is a difference between reporting a
cross section in the (unknown) real flux, and reporting a cross section that
was extrapolated from the (unknown) real flux to a fixed reference flux. A lot
of (most?) current analyses do the former, while the results are compared to
model predictions as if they were the latter. This leads to (part of) the flux
shape uncertainty being ignored, potentially leading to wrong physics
conclusions. The size of the effect is estimated to be sub-dominant, but
non-negligible in two example measurements from T2K and MINERvA. This paper
describes how the issue arises and provides instructions for possible ways how
to treat the flux shape uncertainties correctly.Comment: 11 pages, 4 figures, accepted manuscrip
Attitudes of surgeons to the use of postoperative markers of the systemic inflammatory response following elective surgery
Background:
Cancer is responsible for 7.6 million deaths worldwide and surgery is the primary modality of a curative outcome. Postoperative care is of considerable importance and it is against this backdrop that a questionnaire based study assessing the attitudes of surgeons to monitoring postoperative systemic inflammation was carried out.
Method:
A Web based survey including 10 questions on the “attitudes of surgeons to the use of postoperative markers of the systemic inflammatory response following elective surgery” was distributed via email. Two cohorts were approached to participate in the survey. Cohort 1 consisted of 1092 surgeons on the “Association of Coloproctology of Great Britain and Ireland (ACPGBI)” membership list. Cohort 2 consisted of 270 surgeons who had published in this field in the past as identified by two recent reviews. A reminder email was sent out 21 days after the initial email in both cases and the survey was closed after 42 days in both cases.
Result:
In total 29 surgeons (2.7%) from cohort 1 and 40 surgeons (14.8%) from cohort 2 responded to the survey. The majority of responders were from Europe (77%), were colorectal specialists (64%) and were consultants (84%) and worked in teaching hospitals (54%) and used minimally invasive techniques (87%). The majority of responders measured CRP routinely in the post-operative period (85%) and used CRP to guide their decision making (91%) and believed that CRP monitoring should be incorporated into postoperative guidelines (81%).
Conclusion:
Although there was a limited response the majority of surgeons surveyed measure the systemic inflammatory response following elective surgery and use CRP measurements together with clinical findings to guide postoperative care. The present results provide a baseline against which future surveys can be compared
Theorising political legitimisation: from stasis to processes.
Legitimacy remains a key concept in political sociology, and perhaps even more so in lay understandings of political processes and structures, as evidenced by conflict over territories and regimes around the world. However, the concept suffers from a rather static representation, and even when addressed in processual form, in terms of specific moments in the process, such as conditions favouring legitimacy or its effects. Building from an Eliasian perspective, we argue for a more processual concept of legitimisation to encompass the dynamic social networks (figurations) that constitute the more unintentional context for deliberate legitimation claims. As networks expand and intensify, processes of legitimisation incorporate changing and more diverse bases for legitimacy claims, as well as a greater variety of such claims and counterclaims. As the power relations between contending groups change, legitimation practices become part of the integrating functions of the state, shaping figurations and the social habitus
The neural basis of metacognitive ability
Ability in various cognitive domains is often assessed by measuring task performance, such as the accuracy of a perceptual categorization. A similar analysis can be applied to metacognitive reports about a task to quantify the degree to which an individual is aware of his or her success or failure. Here, we review the psychological and neural underpinnings of metacognitive accuracy, drawing on research in memory and decision-making. These data show that metacognitive accuracy is dissociable from task performance and varies across individuals. Convergent evidence indicates that the function of the rostral and dorsal aspect of the lateral prefrontal cortex (PFC) is important for the accuracy of retrospective judgements of performance. In contrast, prospective judgements of performance may depend upon medial PFC. We close with a discussion of how metacognitive processes relate to concepts of cognitive control, and propose a neural synthesis in which dorsolateral and anterior prefrontal cortical subregions interact with interoceptive cortices (cingulate and insula) to promote accurate judgements of performance
- …