bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple analyses redirect management and restoration priorities for a critically endangered ecological community
Authors: Tierney David A. , Gallagher Rachael V. , Allen Stuart , Auld Tony D.
Published: February 2021

Accurately assessing community diversity patterns across distributional ranges is critically important for informed and effective management of ecological communities. Yet, for many wide‐ranging communities diversity patterns across broad ranges are poorly known. We apply a range of analytical approaches to an extensively studied ecological community to determine the relative utility and complementarity of these analytical approaches and their applicability for improved management. White Box Yellow Box Blakely’s Red Gum Woodland (herein abbreviated to BGW) occurs across seven bioregions in New South Wales, eastern Australia. Previous work has suggested either small levels of regional variation in floristic patterns or, contrastingly, up to ~80 variants determined by expert‐driven assessment. We undertook floristic survey and analysed floristic patterns using multivariate dispersion, diversity metrics (alpha (α) diversity, beta (β) diversity, gamma (γ) diversity and zeta (ζ) diversity; including assessments of β turnover and nestedness and higher order ζ diversity). Expert‐derived BGW variants were not clearly related to patterns of floristic variation. In this study, multivariate interactions were critical to identifying patterns of floristic variation. ζ diversity provided insights into bioregional variation not detected via other analytics and was more robust to unbalanced data than β diversity. However, β diversity provided important insights, detecting changing community patterns within a bioregion that would otherwise not be detected and allowing for some comparison of our results with other studies. This study highlights the value of applying multiple analytical approaches to the understanding of floristic patterns. Conservation of floristic diversity in BGW requires protection and management across its range, something which has not previously been adequately addressed.
Driving CAR T cells towards dermatologic oncology
Authors: Uslu Ugur
Published: February 2021

Whereas approximately half of metastatic melanoma patients benefit from combined immune checkpoint inhibition targeting cytotoxic T‐lymphocyte‐associated protein 4 (CTLA‐4) and Programmed cell death protein 1 (PD‐1), for those who do not respond, further strategies and treatment options need to be developed. Thus, focus is turning to the use of chimeric antigen receptor (CAR) T cells, a novel therapy that has not yet achieved a major breakthrough in solid tumors despite the impressive response rates reported for their use in hematologic malignancies. In melanoma and other solid tumor entities, different problems still need to be addressed to improve this therapy, with mechanisms to counteract tumor escape being one of them. In this context, we could show the feasibility of combining two different transfection methods – lentiviral transduction and RNA‐electroporation – for equipping the same T lymphocyte with two different tumor antigen‐specific receptors. While further analysis is required to transfer this novel strategy from bench to bedside, appropriate target antigens that avoid on‐target/off‐tumor toxicities and additional optimization to increase CAR T cell power are also needed to maximize their potential use in dermatologic oncology.
The relationship between hydroregime and coho salmon (Oncorhynchus kisutch) redd construction in the Smith River, Oregon
Authors: Butler Mackenzie B. , Flitcroft Rebecca L. , Giannico Guillermo
Published: February 2021

Abstract

Adult salmonid migration to natal habitats and spawning are affected both by physiological factors and environmental conditions. While research has focused on physiological thresholds that influence the initiation of migration, few studies have investigated the relationship between both hydrological and thermal conditions and salmon spawning throughout the course of the reproductive period. We examined whether Oregon coastal coho salmon (Oncorhynchus kisutch) returning to three tributaries of the Smith River watershed (in the central Oregon Coast Range) responded to the stream hydroregime throughout their spawning period. Generalised linear mixed models were constructed to evaluate relationships between various stream discharge metrics, water temperature and redd count data collected between 2010 and 2016. Across the three sub‐basins we analysed, discharge and temperature metrics were important in explaining redd construction timing. However, the same parameters were not consistently important for every sub‐basin. Water temperature was important in explaining redd construction in the largest sub‐basin, North Sister Creek, and discharge metrics were consistently important in Beaver Creek, the smallest sub‐basin. At the sub‐basin scale, peak redd construction by coho salmon starts after increase in discharge (25th percentile) occurs but before the highest discharge events take place. However, synchrony among sub‐basins was evident in delayed redd construction during 2013 when the autumn rains were delayed. Understanding relationships between the timing of redd construction and characteristics of the hydrological regime are critical to analysis of potential future climate impacts on all life stages of Oregon Coastal coho salmon.
Low prevalence of antiannexin A5 antibodies in unprovoked venous thrombosis
Authors: Ho Wai Khoon , Rigano Joseph
Published: February 2021

Introduction

The antiphospholipid syndrome (APS) is characterized by thrombosis or pregnancy morbidity, and the detection in the blood of at least one of three antiphospholipid antibodies (lupus anticoagulant, or anticardiolipin or anti‐β2‐glycoprotein I antibodies). Diagnosing APS is important so that secondary prophylaxis may be administered to reduce risk of recurrent thrombosis and/or pregnancy morbidity. In addition to APS‐defining antibodies, there may be additional autoantibodies that have a role in thrombosis and/or pregnancy morbidity. Furthermore, some patients have clinical manifestations highly suggestive of APS but are persistently negative for the APS‐defining antibodies (“seronegative APS”) and instead, have other autoantibodies. Antiannexin A5 (aANXA5) autoantibodies have been associated with increased risk of thrombosis and pregnancy morbidity; levels are also reportedly higher in patients with venous thrombosis compared with healthy controls. The prevalence of aANXA5 among patients with unprovoked venous thrombosis is not well‐documented and determination of the frequency of aANXA5 is the objective of this study.

Methods

We analysed sera from 148 patients with unprovoked venous thrombosis who had undergone routine laboratory testing for the present APS‐defining antibodies.

Results

aANXA5 IgG and IgM were present in 6% and 1%, respectively.

Conclusion

Prevalence of these antibodies in unprovoked venous thrombosis is comparable with frequencies reported in healthy individuals and is far lower than the prevalence in women with pregnancy morbidity. This may indicate lack of association with venous thrombosis, however, adequately powered case‐control studies will be required to resolve this and prevalence data from this study will assist in the design of such studies.
The COVID‐19 epidemic in Madagascar: clinical description and laboratory results of the first wave, march‐september 2020
Authors: Randremanana Rindra Vatosoa , Andriamandimby Soa‐Fy , Rakotondramanga Jean Marius , Razanajatovo Norosoa Harline , Mangahasimbola Reziky Tiandraza , Randriambolamanantsoa Tsiry Hasina , Ranaivoson Hafaliana Christian , Rabemananjara Harinirina Aina , Razanajatovo Iony , Razafindratsimandresy Richter , Rabarison Joelinotahiana Hasina , Brook Cara E. , Rakotomanana Fanjasoa , Rabetombosoa Roger Mario , Razafimanjato Helisoa , Ahyong Vida , Raharinosy Vololoniaina , Raharimanga Vaomalala , Raharinantoanina Sandratana Jonhson , Randrianarisoa Mirella Malala , Bernardson Barivola , Randrianasolo Laurence , Randriamampionona Léa Bricette Nirina , Tato Cristina M. , DeRisi Joseph L. , Dussart Philippe , Vololoniaina Manuela Christophère , Randriatsarafara Fidiniaina Mamy , Randriamanantany Zely Arivelo , Heraud Jean‐Michel
Published: February 2021

Background

Following the first detection of SARS‐CoV‐2 in passengers arriving from Europe on 19 March 2020, Madagascar took several mitigation measures to limit the spread of the virus in the country.

Methods

Nasopharyngeal and/or oropharyngeal swabs were collected from travellers to Madagascar, suspected SARS‐CoV‐2 cases and contact of confirmed cases. Swabs were tested at the national reference laboratory using real‐time RT‐PCR. Data collected from patients were entered in an electronic database for subsequent statistical analysis. All distribution of laboratory‐confirmed cases were mapped, and six genomes of viruses were fully sequenced.

Results

Overall, 26,415 individuals were tested for SARS‐CoV‐2 between 18 March and 18 September 2020, of whom 21.0% (5,553/26,145) returned positive. Among laboratory‐confirmed SARS‐CoV‐2–positive patients, the median age was 39 years (IQR: 28‐52), and 56.6% (3,311/5,553) were asymptomatic at the time of sampling. The probability of testing positive increased with age with the highest adjusted odds ratio of 2.2 [95% CI: 1.9‐2.5] for individuals aged 49 years and more. Viral strains sequenced belong to clades 19A, 20A and 20B indicative of several independent introduction of viruses.

Conclusions

Our study describes the first wave of the COVID‐19 in Madagascar. Despite early strategies in place Madagascar could not avoid the introduction and spread of the virus. More studies are needed to estimate the true burden of disease and make public health recommendations for a better preparation to another wave.
Are tree plantations promoting homogenization of mammal assemblages between regions with contrasting environments?
Authors: Iezzi María Eugenia , De Angelo Carlos , Cruz Paula , Varela Diego , Di Bitetti Mario S.
Published: February 2021

Aim

The expansion of agriculture is promoting the loss of natural environments and their biotic homogenization. We aimed at understanding whether the replacement of forests and grasslands by tree plantations leads to biotic homogenization of mammal assemblages of two contrasting Neotropical ecoregions or if dispersal or environmental limitations keep their original assemblages clearly differentiated.

Location

Argentina, Upper Paraná Atlantic Forest, Southern Cone Mesopotamian Savannas and Iberá marshes.

Taxon

Mammals.

Methods

We conducted two camera‐trap surveys, deploying 184 camera‐trap stations in continuous forest, fragmented forest and pine plantations in the Atlantic Forest, and 234 in grassland, fragmented forest and pine plantations in the Mesopotamian Savannas. We evaluated the similarity of the assemblages among the environments and regions, generating all possible pairwise comparisons using three similarity indices: Sørensen (species identity), Horn (common species) and Morisita‐Horn (dominant species). Using variation partitioning diagrams and redundancy analysis, we evaluated the spatial structure of mammal assemblages and the influence of environmental variables.

Results

There was a greater similarity in species identity between different environments within each region than between similar environments in different regions. Common and dominant mammal assemblages of tree plantations tended to be similar between regions and were different from assemblages of the natural environments within the same region. Fragmented forest assemblages were very similar among regions. Assemblages were spatially structured but most of the variation between regions was explained by the environmental variables.

Main conclusions

Each region has a distinct pool of species, which is partially explained by environmental factors, such as the differential representation of native environments in the landscape. However, an expansion of tree plantations and forest fragmentation in the Atlantic Forest could lead to biotic homogenization between regions due to an increase in the abundance of generalist species.
Relationship of an adherence score with blood pressure control status among patients with hypertension and their determinants: Findings from a nationwide blood pressure screening program
Authors: Chia Yook Chin , Devaraj Navin Kumar , Ching Siew Mooi , Ooi Pei Boon , Chew Ming Tsuey , Chew Bee Nah , Mohamed Mohazmi , Lim Hooi Min , Beh Hooi Chin , Othman Azli Shahril , Husin Hanis Saadah , Mohamad Gani Abdul Hafiz , Hamid Dalyana , Kang Pei San , Tay Chai Li , Wong Ping Foo , Hassan Haslinda
Published: February 2021

This study aimed to examine the relationship of adherence with blood pressure (BP) control and its associated factors in hypertensive patients. This cross‐sectional nationwide BP screening study was conducted in Malaysia from May to October 2018. Participants with self‐declared hypertension completed the Hill‐Bone Compliance to High Blood Pressure Therapy Scale (Hill‐Bone CHBPTS) which assesses three important domains of patient behavior to hypertension management namely medication taking, appointment keeping and reduced salt intake. Lower scores indicate better compliance while higher scores indicate otherwise. Participant's body mass index and seated BP were measured based on standard measurement protocol. Determinants of adherence to treatment were analyzed using multiple linear regression. Out of 5167 screened subjects, 1705 were known hypertensives. Of these, 927 (54.4%) answered the Hill‐Bone CHBPTS and were entered into analysis. The mean age was 59.0 ± 13.2 years, 55.6% were female and 42.2% were Malays. The mean Hill‐Bone CHBPTS score was 20.4 ± 4.4 (range 14‐47), and 52.1% had good adherence. The mean systolic BP and diastolic BP were 136.4 ± 17.9 and 80.6 ± 11.6 mmHg, respectively. BP was controlled in 58.3% of those with good adherence compared to 50.2% in those with poor adherence (p = .014). Based on multiple linear regression analysis, female gender (β = −0.72, 95% confidence interval [CI] −1.30, −0.15, p = .014), older age (β = −0.05, 95% CI −0.07, −0.03, p < .001), and individuals with primary or lower educational level (β = −0.91, 95% CI −1.59, −0.23, p = .009) had better adherence to BP management. Interventional programs targeted at the less adherent groups are needed in order to improve their adherence and BP control.
Decision‐making capacity assessment education
Authors: Charles Lesley , Brémault‐Phillips Suzette , Pike Ashley , Vokey Camelia , Kilkenny Tara , Johnson Melissa , Tian Peter G. J. , Babenko Oksana , Dobbs Bonnie , Parmar Jasneet
Published: February 2021

Background/Objectives

As the elderly population and associated number of persons with dementia increase, so does the need for decision‐making capacity assessments (DMCAs). Many healthcare professionals (HCPs), however, do not feel prepared to conduct DMCAs. We have provided 4‐h DMCA workshops to HCPs since 2006 and offered physicians either a 3‐h or 2‐day DMCA workshop from 2013 to present. We evaluated the effectiveness of the workshops on self‐reported key concepts of capacity.

Design

Pre‐/post‐test design.

Setting

DMCA workshops for physicians across Canada and HCPs within Alberta.

Participants

Two hundred and eighty‐one physicians and 835 HCPs.

Measurements

Pre‐/post‐workshop ratings on level of comfort with and understanding of 15 core DMCA concepts using 4‐point Likert‐type items.

Results

For the DMCA workshops among physicians, ten 3‐h workshops were held in 2014–2015 with 166 participants and seven 2‐day workshops, between 2014 and 2018, with 115 participants. With respect to the self‐report on core DMCA concepts, at least 62.7% (range: 62.7%–89.6%) of physician participants had higher post‐workshop ratings (sign test; p < 0.001) than pre‐workshop ratings for all core DMCA concepts. For the DMCA workshops among HCPs, 4‐h workshops were delivered to 835 HCP participants from 2008 to 2012. At least 49.6% of participants (range: 49.6%–78.9%) had increased post‐workshop ratings (sign test; p < 0.001) for all level of comfort items with and understanding of core DMCA concepts.

Conclusion

There is a need for DMCA training for physicians and HCPs. The content and method of the workshops are effective at enhancing self‐reported level of comfort with and understanding of core DMCA concepts.
Development and validation of a real‐time method characterizing spontaneous pain in women with dysmenorrhea
Authors: Kantarovich Diana , Dillane Katlyn E. , Garrison Ellen F. , Oladosu Folabomi A. , Schroer Margaret S. , Roth Genevieve E. , Tu Frank F. , Hellman Kevin M.
Published: February 2021

Aim

Prior research has primarily focused on static pain assessment, largely ignoring the dynamic nature of pain over time. We used a novel assessment tool for characterizing pain duration, frequency, and amplitude in women with dysmenorrhea and evaluated how these metrics were affected by naproxen treatment.

Methods

Dysmenorrheic women (n = 25) rated their menstrual pain by squeezing a pressure bulb proportional to the magnitude of their pain. To evaluate whether bulb squeezing was affected by naproxen, we compared parameters before and after naproxen. We also analyzed the correlation between pain relief on a numerical rating scale to changes in bulb squeezing parameters. Random bulb‐squeezing activity in pain‐free participants (n = 14) was used as a control for nonspecific effects or bias.

Results

In dysmenorrheic women, naproxen reduced the duration of the squeezing during a painful bout, the number of painful bouts and bout intensity. Before naproxen, the correlation between these bulb squeeze parameters and self‐reported pain on numeric rating scale was not significant (R2 = 0.12, p = 0.304); however, there was a significant correlation between changes in bulb squeeze activity and self‐reported pain relief after naproxen (R2 = 0.55, p < 0.001).

Conclusion

Our study demonstrates a convenient technique for continuous pain assessment, capturing three different dimensions: duration, frequency, and magnitude. Naproxen may act by reducing the duration and frequency of episodic pain in addition to reducing the severity. After further validation, these methods could be used for other pain conditions for deeper phenotyping and assessing novel treatments.
Postural orthostatic tachycardia syndrome is associated with significant employment and economic loss
Authors: Bourne Kate M. , Chew Derek S. , Stiles Lauren E. , Shaw Brett H. , Shibao Cyndya A. , Okamoto Luis E. , Garland Emily M. , Gamboa Alfredo , Peltier Amanda , Diedrich André , Biaggioni Italo , Sheldon Robert S. , Robertson David , Raj Satish R.
Published: February 2021

Background

Postural orthostatic tachycardia syndrome (POTS) is a debilitating form of chronic orthostatic intolerance that primarily affects women and causes substantial impairment in quality of life and function. Yet, there is minimal literature describing the employment and economic consequences of POTS. We explored these aspects of the POTS patient experience through a self‐reported study designed using community‐based participatory research principles.

Methods and results

A comprehensive questionnaire, including employment and economic consequences, was developed in partnership with Dysautonomia International, a patient advocacy organization. The POTS community engaged in all stages of the research design and analysis. Participants were recruited through Dysautonomia International’s website and social media channels. The analysis included 5,556 adult (age ≥18 years) participants with a physician‐confirmed diagnosis of POTS. The majority of participants were female (95%). Forty‐eight per cent of participants reported employment during the three months prior to the survey, and of these participants, 66.8% would work greater hours if not for illness limitations. Over two‐thirds (70.5%) of participants have lost income due to POTS symptoms, with 36.0% of the total cohort losing more than $10,000 USD in the 12 months prior to the survey. Almost all (95%) participants reported POTS‐related out‐of‐pocket medical expenses since diagnosis, with 51.1% of participants spending $10,000 USD or more.

Conclusions

This is the largest study reporting the employment and economic challenges experienced by individuals with POTS. Exposure of these challenges emphasizes the need for earlier diagnosis and improved therapeutic strategies to reduce the negative individual and societal consequences of this disorder.
Implementation of multidisciplinary reflective rounds within a children's hospital before and during the COVID‐19 pandemic
Authors: Baker Jonathan , Savage Amy , Pendleton Shannon , Bate Jessica M
Published: February 2021

Aim

Regular reflective practice within a large group setting has been shown to reduce levels of burnout in healthcare professionals. We describe how regular reflective rounds were designed and implemented within an existing educational program at a UK children's hospital and report on the feedback received from participants.

Methods

Eight face‐to‐face reflective rounds took place in Southampton Children's Hospital, UK, from September 2017 to February 2020 with a further virtual round in July 2020 during the COVID‐19 pandemic. Each round was facilitated by a clinical psychologist and consultant. For each round, up to three volunteer panellists from different staff groups were invited to share their personal experiences on a pre‐selected subject to the large group. The group would then contribute to the discussion by offering their own reflections. Feedback forms were distributed to attendees and collated.

Results

Eight rounds were held with mean attendance of 32 (range 19–47). Across the eight rounds, the total attendance was 256 staff members. The virtual round had 20 participants. Feedback was received from 202 participants. The majority (98%) would recommend the rounds to colleagues with 64 participants (32%) rating the rounds as ‘exceptional’ and 91 (45%) as ‘excellent’. The virtual round received similar positive feedback.

Conclusion

Large group reflective practice can be implemented within an existing regular educational program. Rounds have been well received by participants and are likely to be of relevance and value to other healthcare groups. The rounds can also be delivered effectively virtually, which may increase participation.
Latex proteins from Plumeria pudica reduce ligature‐induced periodontitis in rats
Authors: Oliveira Lucas E. S. , Moita Lucas A. , Souza Bruna S. , Oliveira Naylla M. V. , Sales Ana C. S. , Barbosa Mayck S. , Silva Francisca D. S. , Farias Alan L. C. , Lopes Victor L. R. , França Luiz F. C. , Alves Even H. P. , Freitas Cleverson D. T. , Ramos Marcio V. , Vasconcelos Daniel F. P. , Oliveira Jefferson S.
Published: February 2021

Background

Previous studies have shown that latex proteins from Plumeria pudica (LPPp) have anti‐inflammatory and antioxidant activity. Therefore, the aim of this study was to evaluate the effects in rats of LPPp on ligature‐induced periodontitis, an inflammatory disease.

Methods

The animals were divided into groups: saline (animals without induction of periodontitis), periodontitis (induced periodontitis and untreated) and LPPp (induced periodontitis and treated with 40 mg/kg). The following parameters were evaluated after 20 consecutive days of treatment: gingival bleeding index (GBI), probing pocket depth (PPD), alveolar bone height (ABH) and gingival myeloperoxidase (MPO) activity. In the hepatic tissue, malondialdehyde (MDA), glutathione (GSH) and histopathological alterations were evaluated. Blood levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured.

Results

Significant reduction in GBI, PPD and gingival MPO activity and ABH was seen in animals treated with LPPp compared with periodontitis. Values of GSH, MDA, ALT and histopathological evaluation were preserved in animals treated with LPPp.

Conclusions

Treatment with LPPp improved clinical aspects of periodontitis, reduced the blood and hepatic alterations and prevented alveolar bone loss. Data suggest that LPPp have potential for treatment of periodontitis.
The historical witch in contemporary young adult literature
Authors: Wörsdörfer Anna Isabell
Published: February 2021

This article conducts a comparative analysis of Les orangers de Versailles (2000) by French novelist Annie Pietri and Die Hexenkinder von Seulberg (2003) by German novelist Uschi Flacke. It examines how these two current young adult novels explore the subject of the early modern witch in general and how they treat the references of the past in particular in order to adapt them for their target audience: adolescent readers. While Pietri transposes the events of the Affair of the Poisons (1676–1682) into an adventurous detective plot—sometimes in a distinctly fairy‐tale manner—Flacke uses contemporary sources such as court records and letters with a decidedly documentary intention to describe the (violent) mechanisms of a rural witch‐hunt in the 1650s. In both novels, the female protagonists are developed in a way that offers young readers opportunities for identification and irritation—a combination that also provides didactic potential for school‐teaching.
Where Did the Party Conflicts Go? How Horizontal Specialization in Political Systems Affects Party Conflicts
Authors: Skoog Louise
Published: February 2021

This article shows that political conflicts are expressed in different arenas and between different actors depending on the degree of horizontal specialization in a political system. In political organizations with a low degree of horizontal specialization, more issues are depoliticized and the discretion of the administration increases. One factor that spurs political conflicts is prioritization between policy fields, rather than within fields. The article is based on an analysis of minutes from Assembly meetings as well as interviews with leading local politicians and Chief Executive Officers in three Swedish municipalities.

Related Articles

Johansson, Karl Magnus, and Tapio Raunio. 2020. “Centralizing Government Communication? Evidence from Finland and Sweden.”Politics & Policy48 (6): 1138‐1160.https://doi.org/10.1111/polp.12370

Nwokora, Zim, and Riccardo Pelizzo. 2015. “The Political Consequences of Party System Change.”Politics & Policy43 (4): 453‐473.http://onlinelibrary.wiley.com/doi/10.1111/polp.12124/abstract

Vercesi, Michelangelo. 2016. “Coalition Politics and Inter‐Party Conflict Management: A Theoretical Framework.”Politics & Policy44 (2): 168‐219.https://doi.org/10.1111/polp.12154
Uniform error estimates for the random batch method to the first‐order consensus models with antisymmetric interaction kernels
Authors: Ko Dongnam , Ha Seung‐Yeal , Jin Shi , Kim Doheon
Published: February 2021

We propose a random batch method (RBM) for a contractive interacting particle system on a network, which can be formulated as a first‐order consensus model with heterogeneous intrinsic dynamics and convolution‐type consensus interactions. The RBM was proposed and analyzed recently in a series of work by the third author and his collaborators for a general interacting particle system with a conservative external force, with particle‐number independent error estimate established under suitable regularity assumptions on the external force and interacting kernel. Unlike the aforementioned original RBM, our consensus model has two competing dynamics, namely “dispersion” (generated by heterogeneous intrinsic dynamics) and “concentration” (generated by consensus forcing). In a close‐to‐consensus regime, we present a uniform error estimate for a modified RBM in which a random batch algorithm is also applied to the part of intrinsic dynamics, not only to the interaction terms. We prove that the obtained error depends on the batch size and the time step , uniformly in particle number and time, namely, ‐error is of . Thus the computational cost per time step is , where is the number of particles and one typically chooses , while the direct summation would cost . Our analytical error estimate is further verified by numerical simulations.
El populismo en Colombia y la obra de Marco Palacios: una reflexión desde los lenguajes políticos
Authors: Santos Gómez David Ernesto
Published: February 2021

Este artículo1 realiza un análisis del concepto de populismo y su relación con la violencia en Colombia entre las últimas tres décadas del siglo XX y la primera del siglo XXI, con particular énfasis en el trabajo pionero del historiador Marco Palacios. Exploramos la idea de que la conceptualización del populismo en Colombia va de la mano, por un lado, con las disputas por la noción de violencia en la segunda mitad del siglo XX y, por otro, con la idea de que “el populismo incompleto” fue una explicación causal de las épocas de sangrientos enfrentamientos armados en el país. Esto, además, ha teñido de cierta idea de excepcionalidad del caso político colombiano respecto al resto de América Latina. Para tal fin recuperaremos algunos aportes teóricos de la historia conceptual de Reinhart Koselleck y de la historia de los lenguajes políticos de Elías Palti.
On the Hydrodynamic Analogy of Torsion
Authors: Den Hartog J. P. , McGivern J. G.
Published: February 2021

The authors herein describe a means for carrying out experimentally Kelvin’s hydrodynamic analogy. A real liquid is used instead of the “ideal fluid” required by the analogy, the eddying flow caused thereby which violates the mathematical identity between the two cases being eliminated by taking photographs of the real liquid before eddying flow begins. The apparatus makes it possible to obtain photographs representing stress lines in shafts and also pictures of warped cross-sections.
An Application of the Interferometer Strain Gage in Photoelasticity
Authors: Vose R. W.
Published: February 2021

This paper was written at the suggestion of Mr. Mieth Maeser, in response to numerous inquiries concerning the methods of photoelastic analysis in use at the Massachusetts Institute of Technology.

By the use of any of the usual photoelastic methods the difference of the principal stresses and their direction at any point in a suitable loaded specimen are determined, and through a knowledge of Poisson’s ratio their sum is obtained (and a solution made possible) by a measurement of the lateral deformation of the specimen by means of an interferometer strain gage. This instrument, together with its accessories and their use, is illustrated and described in the paper. Examples of the problems solved by the use of the instrument show its accuracy and the consistency of the results obtained by the method.
Influence of Cu-Water and CNT-Water Nanofluid on Natural Convection Heat Transfer in a Triangular Solar Collector
Authors: Redwan Didarul Ahasan , Rahman Md. Habibur , Prince Hasib Ahmed , Chowdhury Emdadul Haque , Amin M. Ruhul
Published: February 2021

A numerical study on natural convection heat transfer in a right triangular solar collector filled with CNT-water and Cuwater nanofluids has been conducted. The inclined wall and the bottom wall of the cavity are maintained at a relatively lower temperature (Tc), and higher temperature (Th), respectively, whereas the vertical wall, is kept adiabatic. The governing non-dimensional partial differential equations are solved by using the Galerkin weighted residual finite element method. The Rayleigh number (Ra) and the solid volume-fraction of nanoparticles (ϕ) are varied in the range of 103 ≤ Ra ≤ 106, and 0 ≤ ϕ ≤ 0.1, respectively, to carry out the parametric simulations within the laminar region. Corresponding thermal and flow fields are presented via isotherms and streamlines. Variations of average Nusselt number as a function of Rayleigh number have been examined for different solid volume-fraction of nanoparticles. It has been found that the natural convection heat transfer becomes stronger with the increment of solid volume fraction and Rayleigh number, but the strength of circulation reduces with increasing nanoparticles’ concentration at low Ra. Conduction mode dominates for lower Ra up to a certain limit of 104. It is also observed that when the solid volume fraction is increased from 0 to 0.1 for a particular Rayleigh number, the average Nusselt number is increased to a great extent, but surprisingly, the rate of increment is more pronounced at lower Ra. Moreover, it is seen that Cu-water nanofluid offers slightly better performance compared to CNT-water but the difference is very little, especially at lower Ra.
Process Capability Based Tolerance Allocation in Pneumatic Percussive Riveting
Authors: Wang Hua , Zhang Jialei , Yu Junyang
Published: February 2021

Pneumatic percussive riveting is an important way to join the sheet metals. In order to ensure the load transfer and the fatigue performance of riveted joint, the interference of the rivet/hole is strictly specified. The interference of the rivet/hole is highly correlated with the process capability of the pneumatic hammer and the diameter of the pre-hole. It is a critical step to choose the appropriate pneumatic hammer to ensure the interference requirements. Energy per blow of the pneumatic hammer is a proclaimed parameter from the riveting hammer manufacturer. It is difficult for the designer to choose the riveting hammer in practical riveting scheme based on energy per blow.

Tolerance analysis is an efficient way to model the manufacturing variation and implement process control. This paper presents the tolerance allocation of the pneumatic percussive riveting based on the process capability of the pneumatic hammer. In order to obtain the designed interferences of the rivet/hole, a tolerance chain is built with the process capability of the pneumatic hammer, the diameter of the pre-hole and the diameter of the rivet shank. The process capability of the pneumatic hammer is represented with the interferences of the rivet/hole after riveting. It is an intuitive parameter for the designer to choose the riveting hammer in practical riveting scheme. The process capability of the pneumatic hammer is obtained from the designed riveting experiments with the pneumatic percussive riveting platform.

The diameter of the pre-hole affects the interference of the rivet/hole also. The tolerance for manual hole-drilling should be determined to assure the interference requirements and high drilling operation efficiency simultaneously. The variation of the pre-hole is obtained from the manual drilling experiments and diameter measurements. Different hole-drilling results in different mating conditions between the pre-hole and the rivet. The fit conditions of different pre-holes are modeled and the final interferences after riveting are analyzed.

Worst case method and statistical analysis method are two common methods for tolerance analysis. For the manual hole-drilling and the pneumatic percussive riveting, worst case method is employed to analyze the constructed tolerance chain in order to accomplish the interferences of the rivet/hole. The different analyzed dimensions, rivet-hole clearances and pre-hole drilling variation, are investigated respectively.

The reported work enhances the understanding of the tolerance allocation for the pneumatic percussive riveting. The interference based process capability of the pneumatic hammer provides good reference for pneumatic hammer choosing in riveting scheme. The reported tolerance chain of the interference could be used for the tolerance determination of manual hole-drilling with good quality and high efficiency.
Non-Contact Measurement of Respiratory Function for Judging the Effect of Respiratory Rehabilitation in Patients With SMID
Authors: Kosumi Remi , Sakamoto Ryota , Kato Norihiko , Yano Ken’ichi , Iwamoto Shotaro , Tsujioka Tomohiro , Takahashi Yuya , Yamakawa Noriko
Published: February 2021

Patients with SMID (severe motor and intellectual disabilities) have severe limb disorders and severe mental disabilities. More than half of their deaths are due to respiratory disorders. Therefore, respiratory rehabilitation is important. The effect of respiratory rehabilitation is generally determined by measuring respiratory volume and rate with an expired gas analyzer. However, the equipment is expensive and requires direct contact, making it difficult to use. The purpose of this research is to develop a non-contact measurement system for respiratory function to assess the effect of respiratory rehabilitation in patients with SMID. The proposed method detects respiration by depth change of the abdomen measured using a three-dimensional camera designed to identify body tremor /motion and respiration based on respiratory parameters and individually adapted parameters. Finally, we verify the rehabilitation effect of an RTX respirator on patients with SMID and the effectiveness of the proposed method in an experiment.
Comparison of Plug Flow and Multi-Node Stratified Tank Modeling Approaches Regarding Computational Efficiency and Accuracy
Authors: Karg Bulnes Fernando , Gluesenkamp Kyle R. , Rendall Joseph
Published: February 2021

Residential water heaters contain water stratified by temperature-driven density differences. This implies that a water tank can reach a state in which the top and bottom sections have different temperatures, unless mixing happens. A high degree of thermal stratification can improve the efficiency of some water heaters, by saving the amount of energy required for the heat-up process. Studies of stratification became popular in the 1970s and it remains an active research topic today. The research has led to the development of different models and techniques to better predict and define a stratified tanks behavior. By comparing these models and techniques used previously to describe thermal stratification, the phenomenon could be better understood, exploited, and used to increase efficiency and thermal energy capacity in modern water tanks. From the existing models, we found the one-dimensional standard plug-flow and a multi node model to be appropriate for analyzing the processes of the heat up and cool-down in a water tank. These two models are based on energy balances. This work involved comparing the accuracy and computational effort needed to implement these models. To assess accuracy, we compared both types of existing models to experimental data (also collected in this work) which included a heat up process using an external heat pump. This external process included a layering process that has an eddy diffusivity at five times the rate of thermal diffusion. For this project, we implemented the models in MATLAB, the multi-paradigm numerical computing environment. We quantified model accuracy using the root mean squared error between modeled data and experimental data for six measured tank temperatures. Comparing the accuracy and the computational time taken to run the simulation provides a method to contrast the performance of each model and a way to rate it. The multi node model was run using from 6 to 96 spatial nodes; the plug flow model was run using 1 to 0.001 °C temperature bin sizes. Additionally, timesteps were varied from 4 to 236 s. The results quantify the tradeoff between accuracy and computational time, providing guidance for simulations to intelligently select the best model type and simulation parameters. This research can be used to validate the pre-existing models and possibly improve the modern water tank.
Quasi-Static and Dynamic Confined Compressive Behavior of Glass Beads by In-Situ X-Ray Micro-Computed Tomography
Authors: Zhang Runyu , Chen Huiluo , Malakooti Sadeq , Oman Simon , Wang Bing , Lu Hongbing , Luo Huiyang
Published: February 2021

Granular materials are one of the most important materials in several industries such as civil engineering, agriculture, and energy production. They are a collection of distinct macroscopic particles. Although these materials appear very simple to be described, they exhibit highly different mechanical behavior under quasi-static and dynamic loading conditions. Traditionally, glass beads have been considered as a benchmark granular material for the fundamental understanding of the mechanics of granular materials under complex mechanical loadings. In this study, we intend to characterize the compressive behavior of glass beads under confinement using in-situ X-ray micro-computed tomography at low (quasi-static) and high strain (dynamic) rates. At high strain rates, samples with similar bulk densities to the quasi-static samples are compressed using a long split Hopkinson pressure bar and later imaged with the tomography system to acquire their volumetric images. In the case of low strain rates, a similar sample is compressed, and subsequently, its volumetric images are captured at the same strain level as the dynamically compressed samples using the long split Hopkinson pressure bar. The volumetric images for each case are then analyzed to determine three-dimensional morphologies and to investigate and compare the damage and crushing characteristics of the glass beads at quasi-static and dynamic loading conditions.
How Does Physical Activity Affect Residual Limb Volume Change, Comfort and Gait Symmetry on Traumatic Transfemoral Amputees?
Authors: Salazar-Salgado Sara , Valencia Fanny , Uribe Alejandro , Rendón-Vélez Elizabeth
Published: February 2021

There is a considerable amount of young adults who become amputees due to war and violence. For this population, a successful adaptation to their prosthesis depends on the socket fit, which in turn is caused by the volume change of the residual limb during the day. The literature reports several investigations on this topic, most of which use subjects walking on a treadmill to simulate their daily activity. However, this studies are focused on transtibial amputees and do not mention the relationship between this physical activity and other variables such as comfort, volume changes and gait. Therefore, the objective of this paper is to determine the effect of physical activity on the volume of the residual limb, the comfort and the symmetry of gait in traumatic transfemoral amputees.

Plaster positive molds of the residual limb, the comfort perception and the gait data of five individuals were obtained at the first time of the day and after three sessions of treadmill walking of 15, 30 and 45 minutes. The positive molds of each individual were scanned and then, the volume was calculated. The gait data was acquired using a marker-based motion capture system and processed to obtain spatio-temporal, kinematic and kinetic parameters, including the Gait Deviation Index (GDI). Based on the literature, specific points of the gait data were selected and the symmetry index was obtain for each of them. A short comfort test was used after each session of treadmill walking. Data was analyzed throughout the tests within each subject. Statistical analysis was performed for the volume and the gait variables to check for statistical significance.

After physical activity, a tendency towards residual limb volume decrease was found on almost all subjects, although it was not significant. The percentage of volume change obtained on almost all subjects are within the range considered “good socket fit” according to previous authors. Our results suggest that transfemoral amputees may have smaller volume changes than transtibial after treadmill walking. Significant difference was found on the symmetry index of “Swing phase” between the baseline and the 45-minute test. The values of gait symmetry on the gait parameters were consistent with previous findings regarding transfemoral amputees. The difference that arise may be due to the sample difference (cause of amputation, difference in prosthetic elements and use of walking aids). The lowest symmetry was noticed on the ankle kinematics. The comfort did not significantly change with the selected amount of physical activity.

In subsequent research, it is recommended to increase the intensity or time of physical activity and/or increase the number of participants. This results can help the understanding of how the socket/residual limb interface behaves which can improve the design and prescription of prosthetic components.
Experimental Investigation of Proton Exchange Membrane Fuel Cell With Platinum and Nafion Along the In-Plane Direction
Authors: Cheng Peng , Tongsh Chasen , Liang Jinqiao , Liu Zhi , Du Qing , Jiao Kui
Published: February 2021

In this study, an experimental study has been performed to investigate the effect of in-plane distribution of Pt and Nafion in membrane electrode assembly (MEA) on proton exchange membrane (PEM) fuel cell. Two types of MEAs, such as the gradient and uniform distributions of Pt catalyst and Nafion, are compared under various operating conditions including cathode flow rate, MEA preparation method, Pt loading and relative humidity (RH).

The catalyst ink is sprayed onto Nafion membrane or gas diffusion layer (GDL) through a pneumatic automatic spraying device manufactured by ourselves. MEA is prepared by hot pressing. The results show that as flow rate decreases, the MEA with gradient distribution will show a higher voltage at a high current density for catalyst coated membrane (CCM) method. For CCM method, gradient distribution can optimize cell performance under low cathode flow rate, but the optimization effect is weakened when flow rate is too low. Compared with CCM method, the gas diffusion electrode (GDE) method makes the difference value of Ohmic resistance between gradient and uniform distribution very larger, resulting in poor performance improvement. For GDE method, gradient distribution shows no optimization for cell performance under different Pt loadings and RH, but a smaller average Pt loading and fully-humidified reactants can reduce the performance distinction between uniform and gradient distribution. The gradient design of Pt and Nafion along the in-plane direction is a promising strategy to improve the performance of PEM fuel cell. Reasonably controlling the gradient distribution of Pt in the plane direction of cathode can reduce the amount of Pt catalysts and improve efficiency.