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2021 ◽  
Vol 154 ◽  
Author(s):  
A.A. Wardlaw ◽  
K. Perrault ◽  
A.D. Roe ◽  
J. Dedes ◽  
C.L. Irwin ◽  
...  

Abstract We describe an experimental protocol for measuring the response of spruce budworm postdiapause larval development to temperature. This protocol is specifically designed to include measurements of development near their upper and lower thermal thresholds. The application of this protocol to a laboratory colony allowed for the first experimental evidence that spruce budworm larval development occurs at temperatures as low as 5 °C and as high as 35 °C, and it provides data to fit stage-specific development models. Our protocol is also designed to minimise mortality near the thermal development thresholds, thus allowing for multigenerational studies. We observed developmental plasticity in larvae reared at constant temperatures, particularly the occurrence of up to 42% of some individuals requiring only five instars to complete development compared to the expected six instars. The occurrence exhibited no clear relation to temperature. Although this protocol is specifically designed for spruce budworm, it provides a template for the study of other species’ developmental responses to temperature.


2021 ◽  
Vol 23 ◽  
Author(s):  
Silas Edwin Rickards ◽  
Teertho Bhattacharya ◽  
Grace Cheng ◽  
Josh Valan ◽  
Zachary Webb

In the last few hundred years, mathematicians have been attempting to describe the topological and algebraic properties of mathematical knots. Regarding the study of knots, there exists a disconnect between examining a knot’s mathematical and physical definitions. This is due to the inherent difference in the topology of an open-ended physical knot and a closed mathematical knot. By closing the ends of a physical knot, this paper presents a method to break this discontinuity by establishing a clear relation between physical and mathematical knots. By joining the ends and applying Reidemeister moves, this paper will calculate the equivalent mathematical prime or composite knots for several commonly used physical knots. In the future, it will be possible to study the physical properties of these knots and their potential to expand the field of mathematical knot theory.


2021 ◽  
Author(s):  
David Escudero Mancebo ◽  
Nieves Fernández Villalobos ◽  
Óscar Martín Llorente ◽  
Alejandra Martínez-Monés

The relation between scientific research and industrial design is fraught with controversy. While the number of academic PhD programs on product design grows because the discipline is in its infancy, there is no consolidated method for systematically approaching the generation of knowledge in this domain. This paper aims to review recently published papers from the four top-ranked journals in engineering design in order to analyse the research methods that are frequently used. The research questions consider the aim and contributions of the papers, as well as which experimental design and which sources of data are being used. Frequency tables show the high variety of approaches and aims of the papers, combining both qualitative and quantitative empirical approaches and analytical methods. Most of the papers focus on methodological concerns or on delving into a particular aspect of the design process. Data collection methods are also diverse without a clear relation between the type of method and the objective or strategy of the research. This paper aims to act as a valuable resource for academics, providing definitions related to research methods and referencing examples, and for researchers, shedding light on some of the weaknesses and challenges for current research in the domain of engineering design.


2021 ◽  
Vol 33 ◽  
pp. 84-87
Author(s):  
Maria Teresa Sciarrone Alibrandi ◽  
Giancarlo Joli ◽  
Rodolfo F. Rivera ◽  
Elena Brioni ◽  
Romina Bucci ◽  
...  

The SARS-CoV-2 (Covid-19) infection affected about 106 million people worldwide and the total amount of casualties now sits at a staggering 2 millions. Chronic Kidney Disease (CKD) emerged as the first risk factor in worst patients, not considering old age. Kidney disease and acute kidney injury have been correlated with a higher chance of death. This combination of CKD and higher Covid-19 related mortality requires immediate response from a prevention point of view at first and then from a therapeutic one. There is not a clear relation between Covid-19 and ADPKD. What can be inferred is the following: Covid uses the ACE2 receptors on cell membranes to “lock on” its target. It is well-established in fact that the RAAS is more active in ADPKD patients and it may represent an additional risk factor for these patients. At the moment three Covid-19 vaccines have been approved, and two of them have been already administered, such as Pfizer BioNTech and Moderna, sharing the same mechanism. AstraZeneca released a third option. All of them are completely safe and reliable, each one with its own feature. Therefore, considering how delicate ADPKD patients are, vaccination is strongly recommended.


2021 ◽  
Vol 13 (12) ◽  
pp. 6586
Author(s):  
Fernando Fraga-Varela ◽  
Esther Vila-Couñago ◽  
Ana Rodríguez-Groba

In recent years, serious games offer great opportunities for learning processes at schools. However, it is unclear whether this type of proposals can offer differentiated answers among the students according to their gender. In this context, the aim of this paper is to know the possible differences that occur in primary school classrooms according to gender, with serious games designed for the development of mathematical fluency, and to examine to what extent these games contribute to the overall school performance. We carried out a quasi-experimental study, including pretest and posttest, without control group and with several experimental groups, and the participation of 284 students from first to fourth grade. The results show that the software benefits boys and girls equally, compared to the previously followed methodology that benefited boys. A clear relation between the results achieved and the performance in the overall students’ grades has also been observed. The conclusions show the potential of serious games in school settings, and the opportunity to approach performance differences based on the gender.


2021 ◽  
Author(s):  
Justinien Tribillon

This article proposes an archaeology of the concept of ‘infrastructure’, focusing specifically on a period ranging from 1842 until 1951, before the term entered the English language from French. In doing so, it contributes to an ongoing discussion on ‘What does infrastructure really mean?’ by deconstructing the omnipresent concept of ‘infrastructure’ as an expression of modernity that has crystallised a sociotechnical imaginary: a relation between technology, space and power. Indeed, our understanding of its etymological, epistemological and intellectual origins is patchy, based on repeated chronological mistakes and conceptual misunderstandings. To put it bluntly: we do not know how the word came to be. By unearthing the origins of ‘infrastructure’, this article aims to contribute to scholarly debates on the definition(s) of infrastructure in social sciences, urban studies, science and technology studies and infrastructure studies. It also wishes to contribute to ongoing debates taking place in the public sphere regarding what should count as ‘infrastructure’. This paper’s findings demonstrate a clear relation to Karl Marx’s ‘historical materialism’; the paper also analyses how the word evolved over a short period of time to become sociotechnical metaphor; finally, the paper demonstrates the emergence of a concept that linked engineering to larger socioeconomic concerns in the 1890s, well before the emergence of ‘infrastructure’ as a key concept of development economics in the 1950s.


Author(s):  
Javier BAENA ◽  
Jesús F. Jordá PARDO ◽  
Elena CARRIÓN SANTAFE ◽  
Concepción TORRES NAVAS ◽  
Pilar CARRAL GONZALEZ ◽  
...  

El Esquilleu cave has one of the most complete Middle Paleolithic stratigraphies of northern Iberia with a complete chronological framework almost continuous from the beginning of MIS3. The complete analysis of the materials including the last section of the sequence corresponding to the last chronological interval of the occupation in the region shows clear evolutionary tendencies by important changes in the composition of the lithic assemblage. Its study confirms a continuous occupation without any gaps during the Mousterian until recent dates but without any Upper Paleolithic presence. This sequence, referenced to the Mousterian settlement of the Picos de Europa mountains, testifies to the existence of a Mousterian presence in northern Iberia with no clear relation to other Cantabrian areas. Consequently, its occupation without a break until the crucial phase of the end of the Middle Paleolithic suggests a non-transitional process in the history of local Neanderthal groups.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2063
Author(s):  
Manuel Chacón-Fuentes ◽  
Leonardo Bardehle Parra ◽  
Ivette Seguel Benítez ◽  
Fernanda Rubilar Vergara ◽  
Daniel Martínez-Cisterna ◽  
...  

In terms of the domestication process in murtilla, studies have found changes in the concentration of phenolic compounds, with reduction of chemical defense of plants, depending on the change in the feeding behavior of insects. Thus, we hypothesized that the domestication of Ugni molinae decreases the content of phenolic compounds and modifies the feeding preference of Chilesia rudis larvae. Leaves of three parental ecotypes and four cultivated ecotypes were used in preference experiments to evaluate the mass gain and leaves consumption of larvae. Phenolic extracts from leaves of U. molinae were analyzed by HPLC. Identified compounds were incorporated in an artificial diet to assess their effect on mass gain, consumption, and survival of the larvae. The presence of phenolic compounds in bodies and feces was also evaluated. In terms of choice assays, larvae preferred parental ecotypes. Regarding compounds, vanillin was the most varied between the ecotypes in leaves. However, plant domestication did not show a reduction in phenolic compound concentration of the ecotypes studied. Furthermore, there was no clear relation between phenolic compounds and the performance of C. rudis larvae. Whether this was because of sequestration of some compounds by larvae is unknown. Finally, results of this study could also suggest that studied phenolic compounds have no role in the C. rudis larvae resistance in this stage of murtilla domestication process.


Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 220
Author(s):  
Sung Ho Chae ◽  
Joon Ha Kim

Osmotic and hydraulic pressures are both indispensable for operating membrane-based desalting processes, such as forward osmosis (FO), pressure-retarded osmosis (PRO), and reverse osmosis (RO). However, a clear relation between these driving pressures has not thus far been identified; hence, the effect of change in driving pressures on systems has not yet been sufficiently analyzed. In this context, this study formulates an actual mathematical relation between the driving pressures of membrane-based desalting processes by taking into consideration the presence of energy loss in each driving pressure. To do so, this study defines the pseudo-driving pressures representing the water transport direction of a system and the similarity coefficients that quantify the energy conservation rule. Consequently, this study finds three other theoretical constraints that are required to operate membrane-based desalting processes. Furthermore, along with the features of the similarity coefficients, this study diagnoses the commercial advantage of RO over FO/PRO and suggests desirable optimization sequences applicable to each process. Since this study provides researchers with guidelines regarding optimization sequences between membrane parameters and operational parameters for membrane-based desalting processes, it is expected that detailed optimization strategies for the processes could be established.


2021 ◽  
Author(s):  
Camila Serra-Pompei ◽  
Ben A. Ward ◽  
Jérôme Pinti ◽  
André W. Visser ◽  
Thomas Kiørboe ◽  
...  

AbstractThe flux of detrital particles produced by plankton is an important component of the biological carbon pump. We investigate how food web structure and organisms’ size regulate particulate carbon export efficiency (the fraction of primary production that is exported via detrital particles at a given depth). We use the Nutrient-Unicellular-Multicellular (NUM) mechanistic size-spectrum model of the planktonic community (unicellular pro-tists and copepods), embedded within a 3D model representation of the global ocean circulation. The ecosystem model generates emergent food webs and size distributions of all organisms and detrital particles. Model outputs are compared to field data. We find that strong predation by copepods increases export efficiency, while protist predation reduces it. We find no clear relation between primary production and export efficiency. Temperature indirectly drives carbon export efficiency by affecting the biomass of copepods. High temperatures, combined with nutrient limitation, result in low growth efficiency, smaller trophic transfer to higher trophic levels, and decreased carbon export efficiency. Even though copepods consume a large fraction of the detritus produced, they do not markedly attenuate the particle flux. Our simulations illustrate the complex relation between the planktonic food web and export efficiency, and highlights the central role of zooplankton and their size structure.Plain Language SummaryPlankton are small organisms that live in the ocean. Plankton remove CO2 from the atmosphere by doing photosynthesis and sinking to the deep ocean, where the CO2 is sequestered. Photosynthesis can be measured by satellites, and therefore, knowing the fraction of photosynthesis that sinks to the deep ocean could allow making more accurate predictions of the concentration of CO2 in the atmosphere. This fraction of photosynthesis that is exported is termed “carbon export efficiency”. However, the drivers that define this carbon export efficiency are not well understood. To explore these drivers, we used computer simulations that include many planktonic organisms in a 3D model of the oceans. The model generates a detailed representation of the body sizes of plankton and of particle sizes, which is one of the main features defining sinking rates of particles in nature. We find that export efficiency is high when large zooplankton consume large amounts of prey. Temperature decreases export efficiency by reducing how efficient large plankton grow. Finally, we do not find a clear relation between photosynthesis and export efficiency, which has been much discussed in the literature. This provides mechanistic explanations to previous field observations and generates new hypotheses to be tested.Key Points:We used a 3D size-spectrum model of the planktonic community to understand the drivers of particulate carbon export efficiencyWe find that high temperature decreases growth efficiency, trophic transfer efficiency and associated carbon export efficiency.Systems that are top-down controlled by zooplankton can have high export efficiencies depending on the size of the dominant zooplankton.


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