scholarly journals Database queries and constraints via lifting problems

Author(s):  
DAVID I. SPIVAK

Previous work has demonstrated that categories are useful and expressive models for databases. In the current paper we build on that model, showing that certain queries and constraints correspond to lifting problems, as found in modern approaches to algebraic topology. In our formulation, each SPARQL graph pattern query corresponds to a category-theoretic lifting problem, whereby the set of solutions to the query is precisely the set of lifts. We interpret constraints within the same formalism, and then investigate some basic properties of queries and constraints. In particular, to any database π, we can associate a certain derived databaseQry(π) of queries on π. As an application, we explain how giving users access to certain parts ofQry(π), rather than direct access to π, improves the ability to manage the impact of schema evolution.

2021 ◽  
Vol 11 (10) ◽  
pp. 4658
Author(s):  
Magdalena Januszek ◽  
Paweł Satora

Quality of plum jerkum is significantly associated to the profile of volatile compounds. Therefore, we decided to assess the impact of various fermentation types on selected properties of plum jerkums, especially compounds which contribute to the aroma of the finished product. We used the following yeast strains: S. cerevisiae S1, H. uvarum H2, and Ethanol RED (S. cerevisiae). Moreover, we considered spontaneous fermentation. S. cerevisiae and H. uvarum strains were isolated during the fermentation of Čačanska Lepotica or Węgierka Dąbrowicka (plum cultivars), respectively. As for fermentation type, spontaneous fermentation of H. uvarum H2 provided the best results. It could be associated to the fact that plum juices fermented with H. uvarum H2 presented the highest concentration of terpenoids, esters, or some higher alcohols. In the current paper, application of indigenous strains of yeasts resulted in the required oenological characteristics, e.g., highest fermentation efficiency and concentration of ethanol was determined in juices fermented with Ethanol RED (S. cerevisiae) and also with S. cerevisiae S1. Our results suggested that indigenous strains of yeasts present in plums demonstrate great potential for the production of plum jerkums of high quality.


BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e039488
Author(s):  
Anna Dowling ◽  
Ellen Slungaard ◽  
Nicola R Heneghan

IntroductionThe prevalence of flight-related neck pain is 70% in UK fast jet pilots; much higher than the general population. The Aircrew Conditioning Programme and direct access physiotherapy exist to minimise the impact on military capability, but a population specific patient-reported outcome measure (PROM) is required to investigate the effectiveness of these. We aimed to explore the experiences of flight-related neck pain to inform the content validity and development of a population specific PROM.MethodsQualitative semistructured interviews combining phenomenological and grounded theory methods, reported using Consolidated criteria for Reporting Qualitative research guidelines. A purposive sample of 10 fast jet pilots with neck pain was recruited. Concept elicitation interviews were audio recorded, transcribed verbatim along with field notes. Data analysis involved subject and methodological expertise used a concept elicitation approach.ResultsParticipants included 10 male fast jet pilots, age 34.7 years. Identified themes included: (1) physical symptoms associated with flying activities; (2) occupational effects revealed modifications of flying, or ‘suboptimal’ performance owing to neck pain; (3) psychological effects revealed feelings or worry and (4) social and activity effects showed impact on out of work time.ConclusionPopulation-specific occupational, psychological and social factors should be considered alongside physical symptoms when managing neck pain in military aircrew. Findings support the development of a PROM specifically designed for military aircrew with neck pain.


2021 ◽  
Vol 11 (8) ◽  
pp. 3580
Author(s):  
Cristina Val-Peón ◽  
Juan I. Santisteban ◽  
José A. López-Sáez ◽  
Gerd-Christian Weniger ◽  
Klaus Reicherter

The SW coast of the Iberian Peninsula experiences a lack of palaeoenvironmental and archaeological data. With the aim to fill this gap, we contribute with a new palynological and geochemical dataset obtained from a sediment core drilled in the continental shelf of the Algarve coast. Archaeological data have been correlated with our multi-proxy dataset to understand how human groups adapted to environmental changes during the Early-Mid Holocene, with special focus on the Mesolithic to Neolithic transition. Vegetation trends indicate warm conditions at the onset of the Holocene followed by increased moisture and forest development ca. 10–7 ka BP, after which woodlands are progressively replaced by heaths. Peaks of aridity were identified at 8.2 and 7. 5 ka BP. Compositional, textural, redox state, and weathering of source area geochemical proxies indicates abrupt palaeoceanographic modifications and gradual terrestrial changes at 8.2 ka BP, while the 7.5 ka BP event mirrors a decrease in land moisture availability. Mesolithic sites are mainly composed of seasonal camps with direct access to the coast for the exploitation of local resources. This pattern extends into the Early Neolithic, when these sites coexist with seasonal and permanent occupations located in inland areas near rivers. Changes in settlement patterns and dietary habits may be influenced by changes in coastal environments caused by the sea-level rise and the impact of the 8.2 and 7.5 ka BP climate events.


2021 ◽  
Vol 47 (1) ◽  
Author(s):  
M. Marano ◽  
F. Rossi ◽  
L. Ravà ◽  
M. Khalil Ramla ◽  
M. Pisani ◽  
...  

Abstract Introduction Acute pediatric poisoning is an emerging health and social problem. The aim of this study is to describe the characteristics of a large pediatric cohort exposed to xenobiotics, through the analysis of a Pediatric Poison Control Center (PPCc) registry. Methods This study, conducted in the Pediatric Hospital Bambino Gesù of Rome, a reference National Pediatric Hospital, collected data of children whose parents or caregivers contacted the PPCc by phone (group “P”), or who presented to the Emergency Department (group “ED”), during the three-year period 2014–2016. Data were prospectively and systematically collected in a pre-set electronic registry. Comparisons among age groups were performed and multivariable logistic regression models used to investigate associations with outcomes (hospital referral for “P”, and hospital admission for “ED”group). Results We collected data of 1611 children on group P and 1075 on group ED. Both groups were exposed to both pharmaceutical and non-pharmaceutical agents. Pharmaceutical agent exposure increased with age and the most common route of exposure was oral. Only 10% among P group were symptomatic children, with gastrointestinal symptoms. Among the ED patients, 30% were symptomatic children mostly with gastrointestinal (55.4%) and neurologic symptoms (23.8%). Intentional exposure (abuse substance and suicide attempt), which involved 7.7% of patients, was associated with older age and Hospital admission. Conclusions Our study describes the characteristics of xenobiotics exposures in different paediatric age groups, highlighting the impact of both pharmacological and intentional exposure. Furthermore, our study shows the utility of a specific PPCc, either through Phone support or by direct access to ED. PPCc phone counselling could avoid unnecessary access to the ED, a relevant achievement, particularly in the time of a pandemic.


Work ◽  
2021 ◽  
pp. 1-14
Author(s):  
Mojtaba K. Danesh ◽  
Ehsan Garosi ◽  
Hamedeh Golmohamadpour

BACKGROUND: The COVID-19 pandemic has put health systems under unprecedented pressure, challenging their workforce, especially nurses. OBJECTIVE: The current paper presented a review of the early literature concerning emerging nursing challenges during the early stages of the COVID-19 pandemic. METHODS: A systematic search of the published literature between January and May 2020 was carried out in Medline, Science Direct, and Google Scholar to identify relevant quantitative and qualitative studies. RESULTS: Twenty-two original articles were retrieved, the majority of which were survey studies from China. Synthesis of the evidence resulted in four overarching themes including “being physically and mentally drained in the face of fear and uncertainty,” “shortage of personal protective equipment and usability issues,” “psychosomatic disturbances among nurses,” and “moderators to mitigate nurses’ challenges.” CONCLUSIONS: Providing care for demanding COVID-19 patients, nurses experienced a gruelling situation, during which a significant amount of psychological and physical distress was inflicted to them. However, receiving proper support from their organization and society could improve the condition substantially. Further research is required to explore the impact of the COVID-19 pandemic on nurses, especially from Western countries.


2015 ◽  
Vol 1762 ◽  
Author(s):  
Jeno Balogh ◽  
Sandra Haynes ◽  
Aaron Brown

ABSTRACTThis paper presents the impact of three undergraduate research projects focusing on constructability assessment of adhesive-based wood-concrete composite structural members, on a solar heating technology that can be utilized in conjunction with this system and how these projects relate to engineering education and program development at Metropolitan State University of Denver (MSU Denver). The sustainable structures topic was pursued within senior project classes offered in summer 2013 and 2014 at MSU Denver. The first project addressed new members, while the second dealt with retrofits. These projects were motivated by faculty research in developing new sustainable construction systems using composites. Since underlining faculty research is on an international scale, students had direct access to researchers world-wide. Such research was used as an instrument in the “Experimental Methods in Structural Engineering” course. The students were also exposed to a broader-range of diverse ideas within the field of research by attending an international conference on timber bridges. The solar furnace project was run in parallel, providing students an opportunity to conduct research targeted at design and performance optimization of the heating units with the intention to assess the benefits of incorporating these devices into future buildings using the sustainable structural system technology. Experiences gained through the undergraduate research activities were applied in the design of a proposed Sustainable Systems Engineering degree program.


2013 ◽  
Vol 805-806 ◽  
pp. 334-337
Author(s):  
Shi Wei Su ◽  
You Wei Zhou ◽  
Wei Xiong

Analysis compares the direct access to a single set of wind power systemTwo groups of wind farm access system directlyMultiple sets of wind farm access system directly And Multiple sets of wind dispersion access system's impact on power system transient stability. And compare the simulation results, Concluded that wind farm access capacity and its topology structure's influence on system transient stability.


2020 ◽  
Vol 115 (11) ◽  
pp. 409-412
Author(s):  
Ricardo Tournier

For over 100 years of tanning research, it is still arguable whether tanning chemicals weaken, strengthen or have an effect on the skin's original collagen fibers. The current paper is a review of the literature regarding the impact of the tanning process on the mechanical properties of leather specifically, tensile and tear strength, that raises several questions about this topic. A call is made for the scientific and technical community to address these questions


2018 ◽  
Vol 10 (12) ◽  
pp. 4384 ◽  
Author(s):  
Ko Koens ◽  
Albert Postma ◽  
Bernadett Papp

In less than two years, the concept of overtourism has come to prominence as one of the most discussed issues with regards to tourism in popular media and, increasingly, academia. In spite of its popularity, the term is still not clearly delineated and remains open to multiple interpretations. The current paper aims to provide more clarity with regard to what overtourism entails by placing the concept in a historical context and presenting results from a qualitative investigation among 80 stakeholders in 13 European cities. Results highlight that overtourism describes an issue that is multidimensional and complex. Not only are the issues caused by tourism and nontourism stakeholders, but they should also be viewed in the context of wider societal and city developments. The article concludes by arguing that while the debate on overtourism has drawn attention again to the old problem of managing negative tourism impacts, it is not well conceptualized. Seven overtourism myths are identified that may inhibit a well-rounded understanding of the concept. To further a contextualized understanding of overtourism, the paper calls for researchers from other disciplines to engage with the topic to come to new insights.


2018 ◽  
Vol 6 (3) ◽  
pp. 280-295
Author(s):  
Shafique-ur Rehman ◽  
Rapiah Mohamed ◽  
Hazeline Ayoup

This paper intends to demonstrate the relationships between the management control system (MCS) as a package elements with organizational performance. Many studies conducted and investigated the impact of the management control system (levers of control) and organizational performance and ignore the elements of MCS as a package. Pakistan textile industry faces a lot of issues regarding MCS as packages elements and due to these issue organizational performance reduced. Therefore, current study portray a framework that consists of some vital elements of control adopted from Malmi and Brown (2008) MCS as a package like planning control, cybernetic controls, rewards and compensation controls, administrative controls, and cultural controls which if empirically investigated would demonstrate the extent of by in Pakistan textile industry and how these controls generate better organizational performance. This suggests that the need for more explanation of Pakistani textile industry managers on the need to adopt better MCS practices as these practices lead to better organizational performance. Although the current paper is conceptual in nature thus, needs an empirical study to address in the light of resource-based view theory.


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