bluuebunny/crossref_metadata_2025 huggingface dataset:
Compact and limited operators
Authors: Bachir Mohammed , Flores Gonzalo , Tapia‐García Sebastián
Published: April 2021

Let be a bounded linear operator between two real normed spaces. We characterize compactness of T in terms of differentiability of the Lipschitz functions defined on X with values in another normed space Z. Furthermore, using a similar technique we can also characterize finite rank operators in terms of differentiability of a wider class of functions but still with Lipschitz flavour. As an application we obtain a Banach–Stone‐like theorem. On the other hand, we give an extension of a result of Bourgain and Diestel related to limited operators and cosingularity.
Cognition in pediatric SDB—Yes, no, maybe?
Authors: Garagozzo Ariana , Hunter Scott J.
Published: April 2021

Numerous studies in the past 10 years have reported on the neurocognitive sequalae of pediatric sleep disordered breathing (SDB). Variations in criteria used to define SDB in conjunction with the wide variety of neuropsychological measures selected to evaluate cognitive consequences of SDB have resulted in discrepancies within the literature. This review summarizes the extent literature regarding cognitive effects of pediatric SDB across domains of global intelligence, attention, executive function, memory, language, and visuospatial ability. This review also addresses the proposed etiology underlying neurocognitive consequences of pediatric SDB. The differences in findings across the literature are highlighted and discussed throughout.
Marriage of 2D Covalent–Organic Framework and 3D Network as Stable Solar‐Thermal Still for Efficient Solar Steam Generation
Authors: Huang Zhongming , Luo Yu‐Hui , Geng Wu‐Yue , Wan Yingpeng , Li Shengliang , Lee Chun‐Sing
Published: April 2021

In this work, a diketopyrrolopyrrole‐based 2D covalent–organic framework (COF) is realized and featured with broadband optical absorption and high solar‐thermal conversion performance. Moreover, a 3D hierarchical structure, referred to as COF‐based hierarchical structure (COFHS), is rationally designed to achieve an enhanced photothermal conversion efficiency. In this water evaporator, diketopyrrolopyrrole is immobilized into conjugated COF to achieve enhanced light absorption, whereas a porous PVA network scaffold is utilized to support COF sheets as well as to enhance the hydrophilicity of the evaporator. Due to this structural advantage, COFHS displays a high solar‐to‐vapor energy conversion efficiency of 93.2%. Under 1 sun AM1.5 G irradiation, a stable water evaporation rate of 2.5 kg m–2 h–1 can be achieved. As a proof‐of‐concept application, a water collection device prepared with the COFHS can achieve high solar‐thermal water collection efficiency of 10.2 L m–2 d–1 under natural solar irradiation. The good solar‐thermal conversion properties and high‐water evaporation rate make the COFHS a promising platform for solar‐thermal water production.
SMEFTsim 3.0 — a practical guide
Authors: Brivio Ilaria
Published: April 2021

Abstract

The SMEFTsim package [1] is designed to enable automated computations in the Standard Model Effective Field Theory (SMEFT), where the SM Lagrangian is extended with a complete basis of dimension six operators. It contains a set of models written in FeynRules and pre-exported to the UFO format, for usage within Monte Carlo event generators. The models differ in the flavor assumptions and in the input parameters chosen for the electroweak sector. The present document provides a self-contained, pedagogical reference that collects all the theoretical and technical aspects relevant to the use of SMEFTsim and it documents the release of version 3.0. Compared to the previous release, the description of Higgs production via gluon-fusion in the SM has been significantly improved, two flavor assumptions for studies in the top quark sector have been added, and a new feature has been implemented, that enables the treatment of linearized SMEFT corrections to the propagators of unstable particles.

SMEFTsim 3.0 is available on the Github website https://SMEFTsim.github.io and on the FeynRules database http://feynrules.irmp.ucl.ac.be/wiki/SMEFT.
Implications of SU(2)L gauge invariance for constraints on Lorentz violation
Authors: Crivellin Andreas , Kirk Fiona , Schreck Marco
Published: April 2021

Abstract

Lorentz invariance may only be broken far above the electroweak scale, since violations are experimentally stringently constrained. Therefore, the Standard-Model Extension parameterizing Lorentz violation (LV) via (higher-dimensional) field theory operators is manifestly SU(2)L gauge-invariant. As a consequence, LV in neutrinos implies LV in charged leptons and vice versa. This allows us to obtain estimated sensitivities for flavour-changing operators in the charged-lepton sector from neutrino oscillations as well as sensitivities for flavour-diagonal neutrino effects from high-precision electron experiments. We also apply this method to an analysis of time-of-flight data for neutrinos (detected by IceCube) and photons from gamma ray bursts where discrepancies have been observed. Our conclusion is that an explanation of the arrival time difference between neutrino and photon events by dim-5 operators in the neutrino sector would lead to unacceptably large LV effects in the charged-lepton sector.
Cybersickness in current-generation virtual reality head-mounted displays: systematic review and outlook
Authors: Caserman Polona , Garcia-Agundez Augusto , Gámez Zerban Alvar , Göbel Stefan
Published: April 2021

Cybersickness (CS) is a term used to refer to symptoms, such as nausea, headache, and dizziness that users experience during or after virtual reality immersion. Initially discovered in flight simulators, commercial virtual reality (VR) head-mounted displays (HMD) of the current generation also seem to cause CS, albeit in a different manner and severity. The goal of this work is to summarize recent literature on CS with modern HMDs, to determine the specificities and profile of immersive VR-caused CS, and to provide an outlook for future research areas. A systematic review was performed on the databases IEEE Xplore, PubMed, ACM, and Scopus from 2013 to 2019 and 49 publications were selected. A summarized text states how different VR HMDs impact CS, how the nature of movement in VR HMDs contributes to CS, and how we can use biosensors to detect CS. The results of the meta-analysis show that although current-generation VR HMDs cause significantly less CS ($$p<0.001$$

p
<
0.001

), some symptoms remain as intense. Further results show that the nature of movement and, in particular, sensory mismatch as well as perceived motion have been the leading cause of CS. We suggest an outlook on future research, including the use of galvanic skin response to evaluate CS in combination with the golden standard (Simulator Sickness Questionnaire, SSQ) as well as an update on the subjective evaluation scores of the SSQ.
Exact parametric causal mediation analysis for a binary outcome with a binary mediator
Authors: Doretti Marco , Raggi Martina , Stanghellini Elena
Published: April 2021

With reference to causal mediation analysis, a parametric expression for natural direct and indirect effects is derived for the setting of a binary outcome with a binary mediator, both modelled via a logistic regression. The proposed effect decomposition operates on the odds ratio scale and does not require the outcome to be rare. It generalizes the existing ones, allowing for interactions between both the exposure and the mediator and the confounding covariates. The derived parametric formulae are flexible, in that they readily adapt to the two different natural effect decompositions defined in the mediation literature. In parallel with results derived under the rare outcome assumption, they also outline the relationship between the causal effects and the correspondent pathway-specific logistic regression parameters, isolating the controlled direct effect in the natural direct effect expressions. Formulae for standard errors, obtained via the delta method, are also given. An empirical application to data coming from a microfinance experiment performed in Bosnia and Herzegovina is illustrated.
Six-year clinical outcomes of implant-supported acrylic vs. ceramic superstructures according to the All-on-4 treatment concept for the rehabilitation of the edentulous maxilla
Authors: Ayna Mustafa , Karayürek Fatih , Jepsen Søren , Emmert Marie , Acil Yahya , Wiltfang Jörg , Gülses Aydin
Published: April 2021

The aim of the current study was to document the long-term clinical results of the use of two prosthetic techniques for the rehabilitation of completely edentulous maxillae according to the “All-on-Four” concept: Fixed, screw-retained prosthesis mounted on a chrome-molybdenum framework with (1) metal-ceramic veneers and (2) Acrylic prosthesis with acrylic resin prosthetic teeth. A total of 34 patients were assigned to subgroups according to their own preference of the superstructure type (ceramics [n: 17] or acrylic resin [n: 17]). Prosthetic complications, marginal bone loss, plaque accumulation, bleeding on probing, bite force and oral-health-related quality of life were assessed over a period of 6 years. Marginal bone loss around implants of the ceramic group remained well within the limits for ‘success’, as defined by the 2007 Pisa consensus over the time (1.43 ± 0.35 mm). However, marginal bone loss was significantly more pronounced around the implants in the acrylic group (2.15 ± 0.30) and the difference between two groups was statistically significant (p: 0.00). Bleeding on probing and plaque accumulation showed also positive correlation with marginal bone loss. Both acrylic and ceramic suprastructures appeared to be equivalent after 6 years; however, ceramic suprastructures revealed superior clinical results in terms of bone loss and plaque accumulation. Current study determines the long-term clinical outcomes of different prosthetic management alternatives in All-on-Four and aids to increase dental professionals’ ability to meet the patients’ expectations.
Monitoring land use and soil salinity changes in coastal landscape: a case study from Senegal
Authors: Thiam Sophie , Villamor Grace B. , Faye Laurice C. , Sène Jean Henri Bienvenue , Diwediga Badabate , Kyei-Baffour Nicholas
Published: April 2021

Soil salinity is a major issue causing land degradation in coastal areas. In this study, we assessed the land use and soil salinity changes in Djilor district (Senegal) using remote sensing and field data. We performed land use land cover changes for the years 1984, 1994, 2007, and 2017. Electrical conductivity was measured from 300 soil samples collected at the study area; this, together with elevation, distance to river, Normalized Difference Vegetation Index (NDVI), Salinity Index (SI), and Soil-Adjusted Vegetation Index (SAVI), was used to build the salinity model using a multiple regression analysis. Supervised classification and intensity analysis were applied to determine the annual change area and the variation of gains and losses. The results showed that croplands recorded the highest gain (17%) throughout the period 1984–2017, while forest recorded 3%. The fastest annual area of change occurred during the period 1984–1994. The salinity model showed a high potential for mapping saline areas (R2 = 0.73 and RMSE = 0.68). Regarding salinity change, the slightly saline areas (2 < EC < 4 dS/m) increased by 42% whereas highly saline (EC > 8 dS/m) and moderately saline (4 < EC < 8 dS/m) areas decreased by 23% and 26%, respectively, in 2017. Additionally, the increasing salt content is less dominant in vegetated areas compared with non-vegetated areas. Nonetheless, the highly concentrated salty areas can be restored using salt-resistant plants (e.g., Eucalyptus sp., Tamarix sp.). This study gives more insights on land use planning and salinity management for improving farmers’ resilience in coastal regions.
Accepting the Exceptional?
Authors: Zwier Jochem
Published: April 2021

This commentary attempts to contribute to a further elucidation of Dominic Smith’s call for a rehabilitation of the transcendental in philosophy of technology. On the one hand, it focuses on why such a rehabilitation is deemed necessary, particularly in light of Smith’s diagnosis of a contemporary tendency towards reification and presentism. Postphenomenology is discussed as a challenge and invitation to further clarify the stakes. On the other hand, this commentary inquires into how Smith envisages the achievement of a rehabilitation of the transcendental. Further attention is given to Smith’s idea of a renewed sense of the transcendental. Following his own cues and situating this renewal in the philosophical tradition, the question whether the involved philosophical praxis should be primarily understood as political is brought to the fore. In so doing, Smith’s reading and extension of Luciano Floridi’s attempts to move beyond Kant receive special attention, since the transcendental is here understood in terms of conditions of feasibility. The challenge put to Smith is to contrast this approach with social-constructivist approaches on the one hand, and Stiegler’s thought regarding technics and the transcendental on the other. Finally, Smith’s commitment to taking exception is analyzed to ask how and which logic is at play there.
Towards a signature pedagogy for design and technology education: a literature review
Authors: McLain Matt
Published: April 2021

Drawing on the work of Lee Shulman, this article reviews literature exploring the concept of signature pedagogies, which are described as having have surface, deep and implicit structures. These structures are complex and changing; concerned with habits of head, hand and heart. Emerging from professional education and now being explored in STEM and Humanities education, they are characteristic forms of teaching and learning that are common across a sector. Common themes emerge from within a range of disciplines including art, built environment, design, music, religious, social work and teacher education. These include the roles of the curriculum, the teacher, the learning environment, as well as capability, uncertainty and the challenges associated with signature pedagogies. Focusing on literature from design education, the paper explores the nature of signature pedagogy in design and technology, as a tool for professional discourse. The conclusions propose a discursive framework for design and technology education in which the structures are tied together by the three fundamental activities of ideating, realising and critiquing; more commonly thought of as designing, making and evaluating. The deep structure being project-based learning, undergirded by the implicit values and attitudes associated with design thinking; including collaboration, creativity, empathy, iteration and problem solving. Design and technology education has something unique to offer the broad and balanced curriculum through its signature pedagogies and the way that knowledge is experienced by learners.
Clinical evaluation of a novel subcutaneous lactate monitor
Authors: Dror Nitsan , Weidling John , White Sean , Ortenzio Francesca , Shreim Samir , Keating Mark T. , Pham Hoang , Radom-Aizik Shlomit , Botvinick Elliot
Published: April 2021

Lactate levels are commonly used as an indirect measure to assess metabolic stress in clinical conditions like sepsis. Dynamic lactate measurements are recommended to assess and guide treatment in patients with shock and other critical care conditions. A minimally invasive, continuous lactate monitor has potential to improve clinical decisions and patient care. The purpose of the study was to evaluate continuous lactate measurements of a novel enzymatic Continuous Lactate Monitor (CLM) developed in our laboratory. Lactate levels were monitored during incremental cycling exercise challenges as a tool for hyperlactatemia. Six healthy individuals 18–45 y/o (4 males, 2 females) participated in the study. CLM devices were inserted subcutaneously in the postero-lateral trunk below the renal angle, one hour before the exercise challenge. Each exercise challenge consisted of a 3 to 12-min warm up period, followed by up to 7, 4-min incremental workload bouts separated by rest intervals. Continuous lactate measurements obtained from CLM were compared with commercial lactate analyzer (Abbott iSTAT) measurements of venous blood (plasma) drawn from the antecubital vein. Blood was drawn at up to 25 time points spanning the duration of before exercise, during exercise, and up to 120 min post exercise. Area under the curve (AUC), and delay time were calculated to compare the CLM readings with plasma lactate concentration. Average plasma lactate concentration increased from 1.02 to 16.21 mM. Ratio of AUC derived from CLM to plasma lactate was 1.025 (0.990–1.058). Average dynamic delay time of CLM to venous plasma lactate was 5.22 min (2.87–10.35). Insertion sites examined 48 h after CLM removal did not show signs of side effects and none required medical attention upon examination. The newly developed CLM has shown to be a promising tool to continuously measure lactate concentration in a minimally invasive fashion. Results indicate the CLM can provide needed trends in lactate over time. Such a device may be used in the future to improve treatment in clinical conditions such as sepsis.
Laser Cladding Treatment for Refurbishing Disc Brake Rotors: Environmental and Tribological Analysis
Authors: Olofsson Ulf , Lyu Yezhe , Åström Anna Hedlund , Wahlström Jens , Dizdar Senad , Nogueira Ana Paula Gomes , Gialanella Stefano
Published: April 2021

In this study, grey cast iron disc brake rotors are refurbished by adding a surface layer through laser cladding. Current methods to deal with replaced rotors mainly include remelting, with a minority fraction disposed in landfill. Both approaches result in a huge waste of resources and an increase in CO2 footprint. From a sustainable point of view, this study aims to evaluate the feasibility of refurbishing brake rotors by a combined environmental and tribological performance approach. A streamlined life cycle assessment is conducted to compare the environmental impacts between producing virgin grey cast iron brake rotors and refurbishing replaced brake rotors by laser cladding. It turns out that the energy consumption and CO2 footprint of the laser cladding refurbished brake rotors are 80% and 90% less than the virgin brake rotors. The results show that the refurbished brake rotor yields higher friction compared to the original cast iron utilizing the same pad material. The wear and particle emissions of the disc brake contact are in this study higher for the laser-cladded one compared to the original cast iron one.
Adolescents’ selfie-taking and selfie-editing: A revision of the photo manipulation scale and a moderated mediation model
Authors: Gioia Francesca , McLean Siân , Griffiths Mark D. , Boursier Valentina
Published: April 2021

‘Selfie practices’ (e.g., editing, filtering, sharing) have become adolescents’ daily behaviors. The increasing centrality of online visual self-presentation might increase adolescents’ appearance-related concerns, problematic monitoring, and photo manipulation (PM). However, few studies focused on body image control in photos (BICP) and PM, and no studies evaluated the influence of selfie-expectancies on photo-taking and photo-editing. Consequently, two studies were conducted. Study1 psychometrically evaluated the PM scale (N = 1353). Study2 evaluated the mediating role of BICP and the moderating role of gender in the relationship between selfie-expectancies and PM (N = 453). The revised PM scale showed good psychometric properties. BICP mediated the relationship between selfie-expectancies and PM and being male significantly affected the relationship between the variables. Implications for adolescents’ appearance-related issues are discussed.
Comment on “A Calibration‐Free Formulation of the Complementary Relationship of Evaporation for Continental‐Scale Hydrology” by J. Szilagyi et al.
Authors: Han Songjun , Tian Fuqiang
Published: April 2021

Szilagyi et al. (2017) proposed an approach to accommodate Brutsaert's (2015) cubic complementary relationship model by scaling down its independent variable xB. This scaling down approach can work under a condition that xB is larger than its counterparts in the cubic equation, but decreases the performance of the model when xB is smaller than its counterparts.
The Arctic Subpolar Gyre sTate Estimate: Description and Assessment of a Data‐Constrained, Dynamically Consistent Ocean‐Sea Ice Estimate for 2002–2017
Authors: Nguyen An T. , Pillar Helen , Ocaña Victor , Bigdeli Arash , Smith Timothy A. , Heimbach Patrick
Published: April 2021

A description and assessment of the first release of the Arctic Subpolar gyre sTate Estimate (ASTE_R1), a data‐constrained ocean‐sea ice model‐data synthesis, is presented. ASTE_R1 has a nominal resolution of 1/3° and spans the period 2002–2017. The fit of the model to an extensive (O(109)) set of satellite and in situ observations was achieved through adjoint‐based nonlinear least squares optimization. The improvement of the solution compared to an unconstrained simulation is reflected in misfit reductions of 77% for Argo, 50% for satellite sea surface height, 58% for the Fram Strait mooring, 65% for Ice Tethered Profilers, and 83% for sea ice extent. Exact dynamical and kinematic consistency is a key advantage of ASTE_R1, distinguishing the state estimate from existing ocean reanalyses. Through strict adherence to conservation laws, all sources and sinks within ASTE_R1 can be accounted for, permitting meaningful analysis of closed budgets at the grid‐scale, such as contributions of horizontal and vertical convergence to the tendencies of heat and salt. ASTE_R1 thus serves as the biggest effort undertaken to date of producing a specialized Arctic ocean‐ice estimate over the 21st century. Transports of volume, heat, and freshwater are consistent with published observation‐based estimates across important Arctic Mediterranean gateways. Interannual variability and low frequency trends of freshwater and heat content are well represented in the Barents Sea, western Arctic halocline, and east subpolar North Atlantic. Systematic biases remain in ASTE_R1, including a warm bias in the Atlantic Water layer in the Arctic and deficient freshwater inputs from rivers and Greenland discharge.
Upward Lightning Takes Its Cue from Nearby Lightning Events
Authors: Thompson Elizabeth
Published: April 2021

Lightning in a thunderstorm changes the electromagnetic field in a way that sparks upward lightning from tall structures.
Layer contribution to optical signals of van der Waals heterostructures
Authors: Wang Su-Yun , Chen Guo-Xing , Guo Qin-Qin , Huang Kai-Xuan , Zhang Xi-Lin , Yan Xiao-Qing , Liu Zhi-Bo , Tian Jian-Guo
Published: April 2021

The contribution from the upper and lower layers to the optical signal of vdWHs is dependent on the thicknesses of 2D materials and substrates.
Interventional oncology: A snapshot of expanding practice
Authors: Khankan Azzam
Published: April 2021

Interventional oncology (IO) was a minor part of interventional radiology. However, with the development of novel technologies and introduction of innovative therapeutics with dramatic transformations in the practice of oncology, IO is facing challenges in adopting and responding to these new changes to maintain its integral role and maximize its potentials in the efficient management of patients with cancer. In this snapshot, some of the novel therapeutic approach principles relevant to IO practice will be explained briefly.
Not Rocket Science: Implementing Efforts to Improve Working Conditions of Social Workers
Authors: Tham Pia
Published: April 2021

The aim of the study was to investigate if the working conditions of child welfare social workers in one municipality would be improved after the implementation of three initiatives: weekly small group supervision for newly educated social workers, team-strengthening activities and training for the team leaders. Five teams consisting of thirty-six child welfare social workers and five team leaders participated. At project start and after the two project years (2017–2018), the social workers’ perception of their working conditions was measured by a questionnaire (QPS Nordic). After the two years the social workers rated several aspects of their working conditions more positively. They were more satisfied with the organisational climate and leadership and with the collaboration in their work group. Turnover, which had been high for many years, had almost stopped and vacancies were now filled. The social workers were now more often satisfied with the quality of their work. Interestingly, these positive changes had occurred at the same time as the social workers now reported higher demands and more often experienced role conflicts. The overall results of this small-scale study indicate that working conditions of social workers can be improved after the implementation of rather modest means.
The Economic Consequences of Sir Robert Peel: A Quantitative Assessment of the Repeal of the Corn Laws
Authors: Irwin Douglas A , Chepeliev Maksym G
Published: April 2021

This paper provides a quantitative general equilibrium evaluation of the repeal of Britain's Corn Laws in 1846. Using a detailed input-output matrix of the British economy in 1841, we find the abolition of Britain's tariff on imported grain left overall welfare roughly unchanged as the static efficiency gains are offset by terms-of-trade losses. Labourers and capital owners gained a slight amount at the expense of landowners. Combining these changes in factor payments with the different consumption patterns across income groups, we find that the top 10% of income earners lost while the bottom 90% of income earners gained.
Heteroduplex DNA formation and homolog pairing in yeast meiotic mutants.
Authors: Nag D K , Scherthan H , Rockmill B , Bhargava J , Roeder G S
Published: April 2021

Previous studies of Saccharomyces cerevisiae have identified several meiosis-specific genes whose products are required for wild-type levels of meiotic recombination and for normal synaptonemal complex (SC) formation. Several of these mutants were examined in a physical assay designed to detect heteroduplex DNA (hDNA) intermediates in meiotic recombination. hDNA was not detected in the rec102, mei4 and hop1 mutants; it was observed at reduced levels in red1, mek1 and mer1 strains and at greater than the wild-type level in zip1. These results indicate that the REC102, MEI4, HOP1, RED1, MEK1 and MER1 gene products act before hDNA formation in the meiotic recombination pathway, whereas ZIP1 acts later. The same mutants assayed for hDNA formation were monitored for meiotic chromosome pairing by in situ hybridization of chromosome-specific DNA probes to spread meiotic nuclei. Homolog pairing occurs at wild-type levels in the zip1 and mek1 mutants, but is substantially reduced in mei4, rec102, hop1, red1 and mer1 strains. Even mutants that fail to recombine or to make any SC or SC precursors undergo a significant amount of meiotic chromosome pairing. The in situ hybridization procedure revealed defects in meiotic chromatin condensation in mer1, red1 and hop1 strains.
A Chlamydomonas genomic library in yeast artificial chromosomes.
Authors: Infante A , Lo S , Hall J L
Published: April 2021

We have constructed and characterized a Chlamydomonas reinhardtii total genomic library in yeast artificial chromosomes (YACs). The library contains 7500 clones with inserts ranging in size from 100-200 kb. The representation of the library was assessed by screening one-third of it with a probe derived from the dispersed repeat, Gulliver, which occurs approximately 13 times in the genome. At least 10 of these Gulliver loci were isolated within 15 independent YACs. Two of these YACs encompass the Gulliver element designated G, which was reported to map to the uni linkage group (ULG). The end clones of these two YACs have been genetically mapped by RFLP analysis in an interspecific cross and thereby shown to be closely linked to the APM locus on the ULG. A third uni-specific YAC has also been isolated and its ends have been mapped by RFLP analysis. Genetic and RFLP analysis of these and other YACs indicates that the frequency of chimeric YACs in the library is very low. The library was constructed in a second generation vector that enables plasmid rescue of YAC end clones as well as copy number amplification of artificial chromosomes. We provide evidence that amplification of intact YACs requires a rad1:rad52 yeast strain.
Defects in Protein Glycosylation Cause SHO1-Dependent Activation of a STE12 Signaling Pathway in Yeast
Authors: Cullen Paul J , Schultz Janet , Horecka Joe , Stevenson Brian J , Jigami Yoshifumi , Sprague George F
Published: April 2021

In haploid Saccharomyces cerevisiae, mating occurs by activation of the pheromone response pathway. A genetic selection for mutants that activate this pathway uncovered a class of mutants defective in cell wall integrity. Partial loss-of-function alleles of PGI1, PMI40, PSA1, DPM1, ALG1, MNN10, SPT14, and OCH1, genes required for mannose utilization and protein glycosylation, activated a pheromone-response-pathway-dependent reporter (FUS1) in cells lacking a basal signal (ste4). Pathway activation was suppressed by the addition of mannose to hexose isomerase mutants pgi1-101 and pmi40-101, which bypassed the requirement for mannose biosynthesis in these mutants. Pathway activation was also suppressed in dpm1-101 mutants by plasmids that contained RER2 or PSA1, which produce the substrates for Dpm1. Activation of FUS1 transcription in the mannose utilization/protein glycosylation mutants required some but not all proteins from three different signaling pathways: the pheromone response, invasive growth, and HOG pathways. We specifically suggest that a Sho1 → Ste20/Ste50 → Ste11 → Ste7 → Kss1 → Ste12 pathway is responsible for activation of FUS1 transcription in these mutants. Because loss of pheromone response pathway components leads to a synthetic growth defect in mannose utilization/protein glycosylation mutants, we suggest that the Sho1 → Ste12 pathway contributes to maintenance of cell wall integrity in vegetative cells.
The Saccharomyces cerevisiae RDN1 Locus Is Sequestered From Interchromosomal Meiotic Ectopic Recombination in a SIR2-Dependent Manner
Authors: Davis Edward S , Shafer Brenda K , Strathern Jeffrey N
Published: April 2021

Meiotic ectopic recombination occurs at similar frequencies among many sites in the yeast genome, suggesting that all loci are similarly accessible to homology searching. In contrast, we found that his3 sequences integrated in the RDN1 (rDNA) locus were unusually poor participants in meiotic recombination with his3 sequences at other sites. We show that the low rate of meiotic ectopic recombination resulted from the poor ability of RDN1::his3 to act as a donor sequence. SIR2 partially repressed interchromosomal meiotic ectopic recombination at RDN1, consistent with its role in regulating recombination, gene expression, and retrotransposition within RDN1. We propose that RDN1 is physically sequestered from meiotic homology searching mechanisms.
MPH1, A Yeast Gene Encoding a DEAH Protein, Plays a Role in Protection of the Genome From Spontaneous and Chemically Induced Damage
Authors: Scheller Jürgen , Schürer Anke , Rudolph Christian , Hettwer Stefan , Kramer Wilfried
Published: April 2021

We have characterized the MPH1 gene from Saccharomyces cerevisiae. mph1 mutants display a spontaneous mutator phenotype. Homologs were found in archaea and in the EST libraries of Drosophila, mouse, and man. Mph1 carries the signature motifs of the DEAH family of helicases. Selected motifs were shown to be necessary for MPH1 function by introducing missense mutations. Possible indirect effects on translation and splicing were excluded by demonstrating nuclear localization of the protein and splicing proficiency of the mutant. A mutation spectrum did not show any conspicuous deviations from wild type except for an underrepresentation of frameshift mutations. The mutator phenotype was dependent on REV3 and RAD6. The mutant was sensitive to MMS, EMS, 4-NQO, and camptothecin, but not to UV light and X rays. Epistasis analyses were carried out with representative mutants from various repair pathways (msh6, mag1, apn1, rad14, rad52, rad6, mms2, and rev3). No epistatic interactions were found, either for the spontaneous mutator phenotype or for MMS, EMS, and 4-NQO sensitivity. mph1 slightly increased the UV sensitivity of mms2, rad6, and rad14 mutants, but no effect on X-ray sensitivity was observed. These data suggest that MPH1 is not part of a hitherto known repair pathway. Possible functions are discussed.
Physical Map of a Conditionally Dispensable Chromosome in Nectria haematococca Mating Population VI and Location of Chromosome Breakpoints
Authors: Enkerli Jürg , Reed Heather , Briley Angela , Bhatt Garima , Covert Sarah F
Published: April 2021

Certain isolates of the plant pathogenic fungus Nectria haematococca mating population (MP) VI contain a 1.6-Mb conditionally dispensable (CD) chromosome carrying the phytoalexin detoxification genes MAK1 and PDA6-1. This chromosome is structurally unstable during sexual reproduction. As a first step in our analysis of the mechanisms underlying this chromosomal instability, hybridization between overlapping cosmid clones was used to construct a map of the MAK1 PDA6-1 chromosome. The map consists of 33 probes that are linked by 199 cosmid clones. The polymerase chain reaction and Southern analysis of N. haematococca MP VI DNA digested with infrequently cutting restriction enzymes were used to close gaps and order the hybridization-derived contigs. Hybridization to a probe extended from telomeric repeats was used to anchor the ends of the map to the actual chromosome ends. The resulting map is estimated to cover 95% of the MAK1 PDA6-1 chromosome and is composed of two ordered contigs. Thirty-eight percent of the clones in the minimal map are known to contain repeated DNA sequences. Three dispersed repeats were cloned during map construction; each is present in five to seven copies on the chromosome. The cosmid clones representing the map were probed with deleted forms of the CD chromosome and the results were integrated into the map. This allowed the identification of chromosome breakpoints and deletions.
Caenorhabditis elegans lin-13, a Member of the LIN-35 Rb Class of Genes Involved in Vulval Development, Encodes a Protein With Zinc Fingers and an LXCXE Motif
Authors: Meléndez Alicia , Greenwald Iva
Published: April 2021

The SynMuv genes appear to be involved in providing a signal that inhibits vulval precursor cells from adopting vulval fates in Caenorhabditis elegans. One group of SynMuv genes, termed class B, includes genes encoding proteins related to the tumor suppressor Rb and RbAp48, a protein that binds Rb. Here, we provide genetic evidence that lin-13 behaves as a class B SynMuv gene. We show that null alleles of lin-13 are temperature sensitive and maternally rescued, resulting in phenotypes ranging in severity from L2 arrest (when both maternal and zygotic activities are removed at 25°), to sterile Multivulva (when only zygotic activity is removed at 25°), to sterile non-Multivulva (when both maternal and zygotic activities are removed at 15°), to wild-type/class B SynMuv (when only zygotic activity is removed at 15°). We also show that LIN-13 is a nuclear protein that contains multiple zinc fingers and a motif, LXCXE, that has been implicated in Rb binding. These results together suggest a role for LIN-13 in Rb-mediated repression of vulval fates.
Long Microsatellite Alleles inDrosophila melanogasterHave a Downward Mutation Bias and Short Persistence Times, Which Cause Their Genome-Wide Underrepresentation
Authors: Harr Bettina , Schlötterer Christian
Published: April 2021

Microsatellites are short tandemly repeated DNA sequence motifs that are highly variable in most organisms. In contrast to mammals, long microsatellites (>15 repeats) are extremely rare in the Drosophila melanogaster genome. To investigate this paucity of long microsatellites in Drosophila, we studied 19 loci with exceptionally long microsatellite alleles. Inter- and intraspecific analysis showed that long microsatellite alleles arose in D. melanogaster only very recently. This lack of old alleles with many repeats indicated that long microsatellite alleles have short persistence times. The size distribution of microsatellite mutations in mutation-accumulation lines suggests that long alleles have a mutation bias toward a reduction in the number of repeat units. This bias causes the short persistence times of long microsatellite alleles. We propose that species-specific, size-dependent mutation spectra of microsatellite alleles may provide a general mechanism to account for the observed differences in microsatellite length between species.
Genetic Analysis of Isometric Growth Control Mechanisms in the Zebrafish Caudal Fin
Authors: Iovine M Kathryn , Johnson Stephen L
Published: April 2021

The body and fins of the zebrafish grow rapidly as juveniles and slower as they reach maturation. Throughout their lives, the fins grow isometrically with respect to the body. Growth of individual fin rays is achieved by the distal addition of bony segments. We have investigated the genetic control of mechanisms that initiate new segments or control size of newly initiated segments. We find that both segment initiation and segment length are regulated during fin growth in wild-type fish. We examined the growth properties of lof and sof fin length mutants for effects on the number and length of fin ray segments. Fins of lof mutants continue to grow rapidly even after wild-type fin growth slows, resulting in positive allometric growth and additional fin ray segments. We suggest that lof mutants bypass mechanisms that limit segment initiation. Isometric growth is retained in sof mutants, resulting in shorter fins one-half the length of wild-type fins. The primary defect in sof mutants is that fin ray segments are shorter than wild-type segments, although segment number is also diminished. Double mutants for sof;lof reveal that segment length and segment number are controlled in different pathways. Our findings suggest that the lof gene product regulates segment initiation and the sof gene product regulates segment length.
Through a Glass, Darkly: Reflections of Mutation From lacI Transgenic Mice
Authors: Stuart Gregory R , Glickman Barry W
Published: April 2021

The study of mutational frequency (Mf) and specificity in aging Big Blue lacI transgenic mice provides a unique opportunity to determine mutation rates (MR) in vivo in different tissues. We found that MR are not static, but rather, vary with the age or developmental stage of the tissue. Although Mf increase more rapidly early in life, MR are actually lower in younger animals than in older animals. For example, we estimate that the changes in Mf are 4.9 × 10−8 and 1.1 × 10−8 mutations/base pair/month in the livers of younger mice (<1.5 months old) and older mice (≥1.5 months old), respectively (a 4-fold decrease), and that the MR are 3.9 × 10−9 and 1.3 × 10−7 mutations/base pair/cell division, respectively (~30-fold increase). These data also permit an estimate of the MR of GC → AT transitions occurring at 5′-CpG-3′ (CpG) dinucleotide sequences. Subsequently, the contribution of these transitions to age-related demethylation of genomic DNA can be evaluated. Finally, to better understand the origin of observed Mf, we consider the contribution of various factors, including DNA damage and repair, by constructing a descriptive mutational model. We then apply this model to estimate the efficiency of repair of deaminated 5-methylcytosine nucleosides occurring at CpG dinucleotide sequences, as well as the influence of the Msh2−/− DNA repair defect on overall DNA repair efficiency in Big Blue mice. We conclude that even slight changes in DNA repair efficiency could lead to significant increases in mutation frequencies, potentially contributing significantly to human pathogenesis, including cancer.
Combined Analyses of Data From Quantitative Trait Loci Mapping Studies: Chromosome 4 Effects on Porcine Growth and Fatness
Authors: Walling Grant A , Visscher Peter M , Andersson Leif , Rothschild Max F , Wang Lizhen , Moser Gerhard , Groenen Martien A M , Bidanel Jean-Pierre , Cepica Stanislav , Archibald Alan L , Geldermann Hermann , de Koning Dirk J , Milan Denis , Haley Chris S
Published: April 2021

For many species several similar QTL mapping populations have been produced and analyzed independently. Joint analysis of such data could be used to increase power to detect QTL and evaluate population differences. In this study, data were collated on almost 3000 pigs from seven different F2 crosses between Western commercial breeds and either the European wild boar or the Chinese Meishan breed. Genotypes were available for 31 markers on chromosome 4 (on average 8.3 markers per population). Data from three traits common to all populations (birth weight, mean backfat depth at slaughter or end of test, and growth rate from birth to slaughter or end of test) were analyzed for individual populations and jointly. A QTL influencing birth weight was detected in one individual population and in the combined data, with no significant interaction of the QTL effect with population. A QTL affecting backfat that had a significantly greater effect in wild boar than in Meishan crosses was detected. Some evidence for a QTL affecting growth rate was detected in all populations, with no significant differences between populations. This study is the largest F2 QTL analysis achieved in a livestock species and demonstrates the potential of joint analysis.
The narrow sheath Duplicate Genes: Sectors of Dual Aneuploidy Reveal Ancestrally Conserved Gene Functions During Maize Leaf Development
Authors: Scanlon Michael J , Chen K David , McKnight Calvin C
Published: April 2021

The narrow sheath mutant of maize displays a leaf and plant stature phenotype controlled by the duplicate factor mutations narrow sheath1 and narrow sheath2. Mutant leaves fail to develop a lateral domain that includes the leaf margins. Genetic data are presented to show that the narrow sheath mutations map to duplicated chromosomal regions, reflecting an ancestral duplication of the maize genome. Genetic and cytogenetic evidence indicates that the original mutation at narrow sheath2 is associated with a chromosomal inversion on the long arm of chromosome 4. Meristematic sectors of dual aneuploidy were generated, producing plants genetically mosaic for NARROW SHEATH function. These mosaic plants exhibited characteristic half-plant phenotypes, in which leaves from one side of the plant were of nonmutant morphology and leaves from the opposite side were of narrow sheath mutant phenotype. The data suggest that the narrow sheath duplicate genes may perform ancestrally conserved, redundant functions in the development of a lateral domain in the maize leaf.
Cats as an Aid to Teaching Genetics
Authors: Christensen Alan C
Published: April 2021

I have used an exercise involving domestic cats in the General Genetics course at the University of Nebraska-Lincoln for the past 5 years. Using a coherent set of traits in an organism familiar to the students makes it easy to illustrate principles of transmission and population genetics. The one-semester course consists primarily of sophomores and juniors who have either taken a one-semester introductory biology course, a one-semester cell biology course, or have a strong high school biology background. The students are given a handout and asked to determine the genotype at seven unlinked loci of at least one cat. To fill out the form, the students have to grasp such concepts as dominance, incomplete dominance, temperature-sensitive mutations, epistatic interactions, sex linkage, and variable expressivity. Completing the form reinforces these concepts as they observe the cat's phenotype and fill in the genotype. I then analyze the collected data and use it in my lectures on population genetics to illustrate the Hardy-Weinberg equilibrium, calculate allele frequencies, and use statistics. This allows the students to look at population genetics in a very positive light and provides concrete examples of some often misunderstood principles.
Booms and Busts in Housing Market and Health Outcomes for Older Americans
Authors: Yue Dahai , Ponce Ninez A
Published: April 2021

Background and Objectives

The US housing market has experienced considerable fluctuations over the last decades. This study aimed to investigate the impacts of housing price dynamics on physical health, mental health, and health-related behaviors for older American outright owners, mortgaged owners, and renters.

Research Design and Methods

We drew longitudinal data from the 1992–2016 Health and Retirement Study and merged it to the 5-digit zip code–level Housing Price Index. The analytic sample comprised 34 182 persons and 174 759 person-year observations. We used a fixed-effects model to identify the health impacts of housing price dynamics separately for outright owners, mortgaged owners, and renters.

Results

A 100% increase in Housing Price Index was associated with a 2.81 and 3.50 percentage points (pp) increase in the probability of reporting excellent/very good/good health status for mortgage owners and renters, respectively. It was also related to a lower likelihood of obesity (1.82 pp) for outright owners and a lesser chance of obesity (2.85 pp) and smoking (3.03 pp) for renters. All of these relationships were statistically significant (p < .05). Renters also experienced significantly decreased depression scores (−0.24), measured by the Center for Epidemiologic Studies—Depression scale, associated with the same housing price changes.

Discussion and Implications

Housing price dynamics have significant health impacts, and renters are more sensitive to fluctuations in the housing market. Our study rules out the wealth effect as the mechanism through which changes in housing prices affect older adults’ health. Our findings may inform policies to promote older adults’ health by investing in local area amenities and improving socioeconomic conditions.