Scalable Reliable SD Erlang Design

This technical report presents the design of Scalable Distributed (SD) Erlang: a set of language-level changes that aims to enable Distributed Erlang to scale for server applications on commodity hardware with at most 100,000 cores. We cover a number of aspects, specifically anticipated architecture, anticipated failures, scalable data structures, and scalable computation. Other two components that guided us in the design of SD Erlang are design principles and typical Erlang applications. The design principles summarise the type of modifications we aim to allow Erlang scalability. Erlang exemplars help us to identify the main Erlang scalability issues and hypothetically validate the SD Erlang design

Tilting mutation of weakly symmetric algebras and stable equivalence

We consider tilting mutations of a weakly symmetric algebra at a subset of simple modules, as recently introduced by T. Aihara. These mutations are defined as the endomorphism rings of certain tilting complexes of length 1. Starting from a weakly symmetric algebra A, presented by a quiver with relations, we give a detailed description of the quiver and relations of the algebra obtained by mutating at a single loopless vertex of the quiver of A. In this form the mutation procedure appears similar to, although significantly more complicated than, the mutation procedure of Derksen, Weyman and Zelevinsky for quivers with potentials. By definition, weakly symmetric algebras connected by a sequence of tilting mutations are derived equivalent, and hence stably equivalent. The second aim of this article is to study these stable equivalences via a result of Okuyama describing the images of the simple modules. As an application we answer a question of Asashiba on the derived Picard groups of a class of self-injective algebras of finite representation type. We conclude by introducing a mutation procedure for maximal systems of orthogonal bricks in a triangulated category, which is motivated by the effect that a tilting mutation has on the set of simple modules in the stable category.Comment: Description and proof of mutated algebra made more rigorous (Prop. 3.1 and 4.2). Okuyama's Lemma incorporated: Theorem 4.1 is now Corollary 5.1, and proof is omitted. To appear in Algebras and Representation Theor

A generalization of Gabriel's Galois covering functors and derived equivalences

Let $G$ be a group acting on a category $\mathcal{C}$. We give a definition for a functor $F\colon \mathcal{C} \to \mathcal{C}'$ to be a $G$-covering and three constructions of the orbit category $\mathcal{C}/G$, which generalizes the notion of a Galois covering of locally finite-dimensional categories with group $G$ whose action on $\mathcal{C}$ is free and locally bonded defined by Gabriel. Here $\mathcal{C}/G$ is defined for any category $\mathcal{C}$ and we do not require that the action of $G$ is free or locally bounded. We show that a $G$-covering is a universal "$G$-invariant" functor and is essentially given by the canonical functor $\mathcal{C} \to \mathcal{C}/G$. By using this we improve a covering technique for derived equivalence. Also we prove theorems describing the relationships between smash product construction and the orbit category construction by Cibils and Marcos (2006) without the assumption that the $G$-action is free. The orbit category construction by a cyclic group generated by an auto-equivalence modulo natural isomorphisms (e.g., the construction of cluster categories) is justified by a notion of the "colimit orbit category". In addition, we give a presentation of the orbit category of a category with a monoid action by a quiver with relations, which enables us to calculate many examples.Comment: Title changed. Definitions of $\mathrm{Mod}^G\mathcal{C}$ and $\mathrm{Mod}_G\mathcal{B}$ in section 6 were corrected. Proof of Theorem 8.1 is slightly changed to make it more readable. Other minor change

Antennal and maxillary palp morphology, and sensillar equipment, of the spruce bark beetle predators, Medetera signaticornis and Medetera infumata (Diptera: Dolichopodidae)

Many long-legged Medetera flies are natural enemies of bark beetle pests, which they detect using ol-factory cues, likely through olfactory sensilla on the antennae and maxillary palps. Morphological characterisation of olfactory sensilla among insects can provide a basis for future taxonomic, phyloge-netic or electrophysiological studies. Scanning electron microscopy was used to describe the morphology of olfactory organs and sensillar equipment of Medetera signaticornis and M. infumata. Three different olfactory sensillum types were found in both fly species, sensilla trichodea, s. basiconica and grooved pegs. Based on size and wall structure, s. trichodea and s. basiconica were categorised into different subtypes. Sharp-tipped curved s. trichodea, and small, large and thin s. basiconica were found on the antennal postpedicel of M. signaticornis adults, while grooved s. basiconica were found in M. infumata. The density of sharp-tipped long s. trichodea was significantly higher in males compared to females, and in M. signaticornis compared to M. infumata. Long-grooved s. basiconica were found grouped in a small pit on the maxillary palps of both species. Comparison of our results with the limited available ecological data suggests that differences in numbers of specific sensillum types may reflect adaptations related to olfactory-driven behaviours such as host seeking.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Seasonal dependence of peroxy radical concentrations at a Northern hemisphere marine boundary layer site during summer and winter: evidence for radical activity in winter

Peroxy radicals (HO2+Σ RO2) were measured at the Weybourne Atmospheric Observatory (52° N, 1° E), Norfolk using a PEroxy Radical Chemical Amplifier (PERCA) during the winter and summer of 2002. The peroxy radical diurnal cycles showed a marked difference between the winter and summer campaigns with maximum concentrations of 12 pptv at midday in the summer and maximum concentrations as high as 30 pptv (10 min averages) in winter at night. The corresponding nighttime peroxy radical concentrations were not as high in summer (3 pptv). The peroxy radical concentration shows a distinct anti-correlation with increasing NOx during the daylight hours. At night, peroxy radicals increase with increasing NOx indicative of the role of NO3 chemistry. The average diurnal cycles for net ozone production, N(O3) show a large variability in ozone production, P(O3), and a large ozone loss, L(O3) in summer relative to winter. For a daylight average, net ozone production in summer was higher than winter (1.51±0.5 ppbv h−1 and 1.11±0.47 ppbv h−1, respectively). The variability in NO concentration has a much larger effect on N(O3) than the peroxy radical concentrations. Photostationary state (PSS) calculations show an NO2 lifetime of 5 min in summer and 21 minutes in the winter, implying that steady-state NO-NO2 ratios are not always attained during the winter months. The results show an active peroxy radical chemistry at night and that significant oxidant levels are sustained in winter. The net effect of this with respect to production of ozone in winter is unclear owing to the breakdown in the photostationary state

Seasonal dependence of peroxy radical concentrations at a northern hemisphere marine boundary layer site during summer and winter: evidence for photochemical activity in winter

International audiencePeroxy radicals (HO2+?RO2) were measured at the Weybourne Atmospheric Observatory (52° N, 1° E), Norfolk using a PEroxy Radical Chemical Amplifier (PERCA) during the winter and summer of 2002. The peroxy radical diurnal cycles showed a marked difference between the winter and summer campaigns with maximum concentrations of 12 pptv at midday in the summer and maximum concentrations as high as 30 pptv (10 min averages) in winter at night. The corresponding nighttime peroxy radical concentrations were not as high in summer (3 pptv). The peroxy radical concentration shows a distinct anti-correlation with increasing NOx during the daylight hours. At night, peroxy radicals increase with increasing NOx indicative of the role of NO3 chemistry. The average diurnal cycles for net ozone production, N(O3) show a large variability in ozone production, P(O3), and a large ozone loss, L(O3) in summer relative to winter. For a daylight average, net ozone production in summer than winter (1.51±0.5 ppbv h?1 and 1.11±0.47 ppbv h?1 respectively) but summer shows more variability of (meteorological) conditions than winter. The variability in NO concentration has a much larger effect on N(O3) than the peroxy radical concentrations. Photostationary state (PSS) calculations show an NO2 lifetime of 5 min in summer and 21 min in the winter, implying that steady-state NO-NO2 ratios are not always attained during the winter months. The results show an active peroxy radical chemistry at night and the ability of winter to make oxidant. The net effect of this with respect to production of ozone in winter is unclear owing to the breakdown in the photostationary state

The geometry of Brauer graph algebras and cluster mutations.

In this paper we establish a connection between ribbon graphs and Brauer graphs. As a result, we show that a compact oriented surface with marked points gives rise to a unique Brauer graph algebra up to derived equivalence. In the case of a disc with marked points we show that a dual construction in terms of dual graphs exists. The rotation of a diagonal in an m-angulation gives rise to a Whitehead move in the dual graph, and we explicitly construct a tilting complex on the related Brauer graph algebras reflecting this geometrical move

Methanol and excited OH masers towards W51: I - Main and South

MERLIN phase-referenced polarimetric observations towards the W51 complex were carried out in March 2006 in the Class II methanol maser transition at 6.668 GHz and three of the four excited OH maser hyperfine transitions at 6 GHz. Methanol maser emission is found towards both W51 Main and South. We did not detect any emission in the excited OH maser lines at 6.030 and 6.049 GHz down to a 3 sigma limit of ~20 mJy per beam. Excited OH maser emission at 6.035 GHz is only found towards W51 Main. This emission is highly circularly polarised (typically 45% and up to 87%). Seven Zeeman pairs were identified in this transition, one of which contains detectable linear polarisation. The magnetic field strength derived from these Zeeman pairs ranges from +1.6 to +6.8 mG, consistent with the previously published magnetic field strengths inferred from the OH ground-state lines. The bulk of the methanol maser emission is associated with W51 Main, sampling a total area of ~3"x2.2" (i.e., ~16200x11900 AU), while only two maser components, separated by ~2.5", are found in the W51 South region. The astrometric distributions of both 6.668-GHz methanol and 6.035-GHz excited-OH maser emission in the W51 Main/South region are presented here. The methanol masers in W51 Main show a clear coherent velocity and spatial structure with the bulk of the maser components distributed into 2 regions showing a similar conical opening angle with of a central velocity of ~+55.5 km/s and an expansion velocity of =<5 km/s. The mass contained in this structure is estimated to be at least 22 solar masses. The location of maser emission in the two afore-mentioned lines is compared with that of previously published OH ground-state emission. Association with the UCHII regions in the W51 Main/South complex and relationship of the masers to infall or outflow in the region are discussed.Comment: 19 pages, 16 figures and 4 tables, accepted for publication in MNRA

Addition to inhaled corticosteroids of long-acting beta2-agonists versus anti-leukotrienes for chronic asthma

Asthma patients who continue to experience symptoms despite being on regular inhaled corticosteroids (ICS) represent a management challenge. Long-acting beta2-agonists (LABA) or anti-leukotrienes (LTRA) are two treatment options that could be considered as add-on therapy to ICS.ObjectivesWe compared the efficacy and safety profile of adding either daily LABA or LTRA in adults and children with asthma who remain symptomatic on ICS.Search strategyWe searched the Cochrane Airways Group Specialised Register (up to and including March 2010). We consulted reference lists of all included studies and contacted authors and pharmaceutical manufacturers for other published or unpublished studies.Selection criteriaWe included randomised controlled trials (RCTs) conducted in adults or children with recurrent asthma that was treated with ICS and where a fixed dose of a long-acting beta2-agonist or leukotriene agent was added for a minimum of 28 days.Data collection and analysisTwo authors independently assessed the risk of bias of included studies and extracted data. We sought unpublished data and further details of study design, where necessary.Main resultsWe included 17 RCTs (7032 participants), of which 16 recruited adults and adolescents (6850) and one recruited children aged 6 to 17 years (182). Participants demonstrated substantial reversibility to short-acting beta-agonist at baseline. The studies were at a low risk of bias. The risk of exacerbations requiring systemic corticosteroids was lower with the combination of LABA and ICS compared with LTRA and ICS, from 11% to 9% (RR 0.83, 95% CI 0.71 to 0.97; six studies, 5571 adults). The number needed to treat (NNT) with LABA compared to LTRA to prevent one exacerbation over 48 weeks was 38 (95% CI 22 to 244). The choice of LTRA did not significantly affect the results. The effect appeared stronger in the trials using a single device to administer ICS and LABA compared to those using two devices. In the absence of data from the paediatric trial and the clinical homogeneity of studies, we could not perform subgroup analyses. The addition to ICS of LABA compared to LTRA was associated with a statistically greater improvement from baseline in several of the secondary outcomes, including lung function, functional status measures and quality of life. Serious adverse events were more common with LABA than LTRA, although the estimate was imprecise (RR 1.35, 95% CI 1.00 to 1.82), and the NNT to harm for one additional patient to suffer a serious adverse event on LABA over 48 weeks was 78 (95% CI 33 to infinity). The risk of withdrawal for any reason in adults was significantly lower with LABA and ICS compared to LTRA and ICS (RR 0.84, 95% CI 0.74 to 0.96).Authors' conclusionsIn adults with asthma that is inadequately controlled on low doses of inhaled steroids and showing significant reversibility with beta2-agonists, LABA is superior to LTRA in reducing oral steroid treated exacerbations. Differences favouring LABA in lung function, functional status and quality of life scores are generally modest. There is some evidence of increased risk of SAEs with LABA. The findings support the use of a single inhaler for the delivery of LABA and inhaled corticosteroids. We are unable to draw conclusions about which treatment is better as add-on therapy for children.PLAIN LANGUAGE SUMMARYWhat are the effects of long-acting beta2-agonists compared with anti-leukotrienes when added to inhaled steroids?People who continue to experience asthma symptoms despite regularly taking inhaled corticosteroids are a challenge for management. It is not clear whether the addition of a long-acting beta2-agonist (LABA) such as formoterol or salmeterol would provide more benefit in comparison with an oral anti-leukotriene agent (LTRA), for example zafirlukast or montelukast.Seventeen trials (16 in adults and one in children) were included in this review and were of good quality. We found that the addition of a LABA provides significantly greater protection against exacerbations requiring oral steroids when compared with a LTRA for adults. Based on the results of our analyses, approximately 38 adults (with a range of between 22 and 244) would need to be treated with a LABA rather than a LTRA for 48 weeks to prevent one experiencing an exacerbation needing a course of oral steroids. The trial on children did not contribute data on the main outcome and therefore we could not draw any conclusions for children.LABAs also led to a greater improvement in lung function, improvement in symptoms, use of rescue medication, quality of life and symptoms compared to the use of LTRAs. The magnitude of the improvements was modest. Serious adverse events were more frequent with LABA than with LTRAs although this result was imprecise. Based on our analyses, around 78 people would need to be treated for 48 weeks with a LABA rather than a LTRA for one of them to experience a serious adverse event. However, due to the lack of precision around our result, the true number could be between 33 and infinity. There are currently insufficient data to draw any conclusions about the effects of these drugs in children

Factors affecting recruitment and retention of nurses who deliver clinical research: A qualitative study

Aim: To provide a better understanding of the factors affecting recruitment and retention of clinical research nurses. Design: Qualitative exploratory design Methods: An on-line questionnaire comprising open-ended and fixed choice questions was completed by 121 clinical research nurses. Seven focus groups were held across three counties with a subgroup of 26 participants. Data were analysed using inductive thematic analysis. Results: Participants were attracted to a research nurse post by an interest in research itself, a desire for a change or to achieve personal objectives. The majority expected to continue in a research nurse post for the next five years while others expected to move on to research management, a clinical post or retirement; few had ambitions to become an independent researcher. Factors identified in focus groups as leading to intentions to leave research included short term contracts, concern about loss of clinical skills, desire for further change, unsupportive employers and limited opportunities for career progression