The Pricing of Housing and Mortgage Services for First-Time Versus Repeat Homebuyers

This study examines efficiency in the pricing of housing and mortgage services across first-time and repeat homebuyers. A logit model is used to test a number of variables for significant differences across first-time buyers and repeat buyers for a sample of brokered real estate sales. The results show that the housing market is somewhat less than completely efficient in providing its services. The logit results for the adjustable-rate mortgage segment show that first-time homebuyers are more likely to be associated with a higher sale price per square foot and higher discount points than repeat buyers. The results show that first-time homebuyers tend to be younger and have less household income than repeat homebuyers. For the full sample of data, the results show that higher sale price/square foot ratios and lower downpayment/sale price ratios are more likely to be associated with first-time homebuyers. For the fixed-rate mortgage segment of the data, the only distinguishing variables are downpayment/sale price and buyer age (both lower for first-time homebuyers). Type of buyer cannot be distinguished by sale price/square foot, contract interest rate, discount points, and other variables. For the adjustable-rate mortgage segment of the data, type of buyer can be distinguished by sale sprice/square foot (higher for first-time buyers), downpayment/sale price (lower for first-time buyers), and discount points (higher for first-time buyers).

Comportamento eletroquímico de dois aços inoxidáveis austeníticos utilizados como biomateriais

O presente trabalho avaliou a resistência à corrosão localizada de dois aços inoxidáveis austeníticos utilizados na fabricação de implantes ortopédicos: o aço ASTM F138, material metálico atualmente mais utilizado em aplicações ortopédicas e o aço ISO 5832-9, aço com adição de nióbio e nitrogênio e que vem sendo apontado como uma alternativa para a substituição do aço F138, para aplicações mais severas de carregamento e tempo de permanência no interior do corpo humano. Ensaios de polarização mostraram que o aço ISO 5832-9 apresenta resistência à corrosão localizada muito superior à do aço F138. O potencial crítico de pite do aço ISO 5832-9 não foi observado na curva de polarização cíclica até o potencial de transpassivação do material. O ensaio potenciostático de corrosão por risco confirmou a superioridade do aço ISO 5832-9. Observou-se a reconstituição do filme passivo danificado mecanicamente, mesmo em potenciais tão elevados como 800 mV SCE. Análises por microscopia eletrônica de varredura confirmaram a presença de pites de corrosão de crescimento estável, na superfície da amostra de aço F 138, e a ausência desses pites, na amostra do aço ISO 5832-9. A maior resistência à corrosão localizada do aço ISO 5832-9 é, principalmente, atribuída ao aumento da estabilidade do filme passivo, sendo favorecida pela presença do nitrogênio em solução sólida intersticial, na austenita desse aço.Potentiodynamic and potentiostatic polarization measurements were conducted in 0.9% NaCl solution to investigate the localized corrosion susceptibility of two austenitic stainless steel biomaterials: a low nitrogen, according to ASTM F 138 - the metallic material most widely utilized today in orthopedic applications; and a nitrogen- and niobium-bearing stainless steel, according to ISO 5832-9, which has shown a promising potential as a substitute of the F 138 steel for more severe loading applications and longer times inside the human body. The polarization tests revealed that the ISO 5832-9 steel is more corrosion resistant than the F 138. The critical pitting potential of the ISO 5832-9 steel could not be observed in the cyclic polarization curve up to the value of potential corresponding to its transpassivity. The potentiostatic scratch test confirmed the superiority of the ISO 5832-9 steel, which heal the mechanically damaged passive film at applied potential as high as 800 mV (SCE). Scanning electron microscopy (SEM) examination confirmed the presence of corrosion pits - lacelike pits - in a stable growth stage on the surface of F 138 steel and the absence of such pits in the specimens of the ISO 5832-9 steel. The higher corrosion resistance of the latter is attributed to the increased stability of the passive film and the high tendency to repassivate, which, in turn, is favored by the presence of nitrogen in interstitial solid solution in the austenite of this type of steel.CNPqFAPES

Comportamento eletroquímico de dois aços inoxidáveis austeníticos utilizados como biomateriais

O presente trabalho avaliou a resistência à corrosão localizada de dois aços inoxidáveis austeníticos utilizados na fabricação de implantes ortopédicos: o aço ASTM F138, material metálico atualmente mais utilizado em aplicações ortopédicas e o aço ISO 5832-9, aço com adição de nióbio e nitrogênio e que vem sendo apontado como uma alternativa para a substituição do aço F138, para aplicações mais severas de carregamento e tempo de permanência no interior do corpo humano. Ensaios de polarização mostraram que o aço ISO 5832-9 apresenta resistência à corrosão localizada muito superior à do aço F138. O potencial crítico de pite do aço ISO 5832-9 não foi observado na curva de polarização cíclica até o potencial de transpassivação do material. O ensaio potenciostático de corrosão por risco confirmou a superioridade do aço ISO 5832-9. Observou-se a reconstituição do filme passivo danificado mecanicamente, mesmo em potenciais tão elevados como 800 mV SCE. Análises por microscopia eletrônica de varredura confirmaram a presença de pites de corrosão de crescimento estável, na superfície da amostra de aço F 138, e a ausência desses pites, na amostra do aço ISO 5832-9. A maior resistência à corrosão localizada do aço ISO 5832-9 é, principalmente, atribuída ao aumento da estabilidade do filme passivo, sendo favorecida pela presença do nitrogênio em solução sólida intersticial, na austenita desse aço.Potentiodynamic and potentiostatic polarization measurements were conducted in 0.9% NaCl solution to investigate the localized corrosion susceptibility of two austenitic stainless steel biomaterials: a low nitrogen, according to ASTM F 138 - the metallic material most widely utilized today in orthopedic applications; and a nitrogen- and niobium-bearing stainless steel, according to ISO 5832-9, which has shown a promising potential as a substitute of the F 138 steel for more severe loading applications and longer times inside the human body. The polarization tests revealed that the ISO 5832-9 steel is more corrosion resistant than the F 138. The critical pitting potential of the ISO 5832-9 steel could not be observed in the cyclic polarization curve up to the value of potential corresponding to its transpassivity. The potentiostatic scratch test confirmed the superiority of the ISO 5832-9 steel, which heal the mechanically damaged passive film at applied potential as high as 800 mV (SCE). Scanning electron microscopy (SEM) examination confirmed the presence of corrosion pits - lacelike pits - in a stable growth stage on the surface of F 138 steel and the absence of such pits in the specimens of the ISO 5832-9 steel. The higher corrosion resistance of the latter is attributed to the increased stability of the passive film and the high tendency to repassivate, which, in turn, is favored by the presence of nitrogen in interstitial solid solution in the austenite of this type of steel.631159166Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Não temNão te

W=0 Pairing in (N,N)(N,N) Carbon Nanotubes away from Half Filling

We use the Hubbard Hamiltonian $H$ on the honeycomb lattice to represent the valence bands of carbon single-wall $(N,N)$ nanotubes. A detailed symmetry analysis shows that the model allows W=0 pairs which we define as two-body singlet eigenstates of $H$ with vanishing on-site repulsion. By means of a non-perturbative canonical transformation we calculate the effective interaction between the electrons of a W=0 pair added to the interacting ground state. We show that the dressed W=0 pair is a bound state for resonable parameter values away from half filling. Exact diagonalization results for the (1,1) nanotube confirm the expectations. For $(N,N)$ nanotubes of length $l$, the binding energy of the pair depends strongly on the filling and decreases towards a small but nonzero value as $l \to \infty$. We observe the existence of an optimal doping when the number of electrons per C atom is in the range 1.2$\div$1.3, and the binding energy is of the order of 0.1 $\div$ 1 meV.Comment: 16 pages, 6 figure

Flow cytometry immunophenotyping for diagnostic orientation and classification of pediatric cancer based on the euroflow solid tumor orientation tube (Stot)

© 2021 by the authors.Early diagnosis of pediatric cancer is key for adequate patient management and improved outcome. Although multiparameter flow cytometry (MFC) has proven of great utility in the diagnosis and classification of hematologic malignancies, its application to non-hematopoietic pediatric tumors remains limited. Here we designed and prospectively validated a new single eight-color antibody combination—solid tumor orientation tube, STOT—for diagnostic screening of pediatric cancer by MFC. A total of 476 samples (139 tumor mass, 138 bone marrow, 86 lymph node, 58 peripheral blood, and 55 other body fluid samples) from 296 patients with diagnostic suspicion of pediatric cancer were analyzed by MFC vs. conventional diagnostic procedures. STOT was designed after several design–test–evaluate–redesign cycles based on a large panel of monoclonal antibody combinations tested on 301 samples. In its final version, STOT consists of a single 8-color/12-marker antibody combination (CD99-CD8/numyogenin/CD4-EpCAM/CD56/GD2/smCD3-CD19/cyCD3-CD271/CD45). Prospective validation of STOT in 149 samples showed concordant results with the patient WHO/ICCC-3 diagnosis in 138/149 cases (92.6%). These included: 63/63 (100%) reactive/disease-free samples, 43/44 (98%) malignant and 4/4 (100%) benign non-hematopoietic tumors together with 28/38 (74%) leukemia/lymphoma cases; the only exception was Hodgkin lymphoma that required additional markers to be stained. In addition, STOT allowed accurate discrimination among the four most common subtypes of malignant CD45− CD56++ non-hematopoietic solid tumors: 13/13 (GD2++ numyogenin− CD271−/+ nuMyoD1− CD99− EpCAM−) neuroblastoma samples, 5/5 (GD2− numyogenin++ CD271++ nuMyoD1++ CD99−/+ EpCAM−) rhabdomyosarcomas, 2/2 (GD2−/+ numyogenin− CD271+ nuMyoD1− CD99+ EpCAM−) Ewing sarcoma family of tumors, and 7/7 (GD2− numyogenin− CD271+ nuMyoD1− CD99− EpCAM+) Wilms tumors. In summary, here we designed and validated a new standardized antibody combination and MFC assay for diagnostic screening of pediatric solid tumors that might contribute to fast and accurate diagnostic orientation and classification of pediatric cancer in routine clinical practice.This research was funded by the EuroFlow Consortium; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro, Brazil (FAPERJ), numbers: E26/110.105/2014, E-26/010.101259/2018, and E26/102.191/2013; grant from Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasília, Brazil (CNPQ), Brasília, Brazil, numbers: 303765/2018-6, 409440/2016-7, and 400194/2014-7; and Instituto Desiderata/Chevron, Rio de Janeiro, Brazil, grant “Actions to improve pediatric cancer assistance in RJ”; the EuroFlow Consortium (grant LSHB-CT-2006-018708); Centro de Investigación Biomédica en Red de Cáncer (CIBER-ONC; Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain and FONDOS FEDER), numbers: CB16/12/00400, CB16/12/00233, CB16/12/00369, CB16/12/00489 and CB16/12/00480; grant from Bilateral Cooperation Program between Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-CAPES (Brasília/Brazil) and Dirección General de Políticas Universitárias (DGPU)-Ministério de Educación, Cultura y Deportes (Madrid/Spain) number DGPU 311/15

Selection Mechanisms Underlying High Impact Biomedical Research - A Qualitative Analysis and Causal Model

BACKGROUND: Although scientific innovation has been a long-standing topic of interest for historians, philosophers and cognitive scientists, few studies in biomedical research have examined from researchers' perspectives how high impact publications are developed and why they are consistently produced by a small group of researchers. Our objective was therefore to interview a group of researchers with a track record of high impact publications to explore what mechanism they believe contribute to the generation of high impact publications. METHODOLOGY/PRINCIPAL FINDINGS: Researchers were located in universities all over the globe and interviews were conducted by phone. All interviews were transcribed using standard qualitative methods. A Grounded Theory approach was used to code each transcript, later aggregating concept and categories into overarching explanation model. The model was then translated into a System Dynamics mathematical model to represent its structure and behavior. Five emerging themes were found in our study. First, researchers used heuristics or rules of thumb that came naturally to them. Second, these heuristics were reinforced by positive feedback from their peers and mentors. Third, good communication skills allowed researchers to provide feedback to their peers, thus closing a positive feedback loop. Fourth, researchers exhibited a number of psychological attributes such as curiosity or open-mindedness that constantly motivated them, even when faced with discouraging situations. Fifth, the system is dominated by randomness and serendipity and is far from a linear and predictable environment. Some researchers, however, took advantage of this randomness by incorporating mechanisms that would allow them to benefit from random findings. The aggregation of these themes into a policy model represented the overall expected behavior of publications and their impact achieved by high impact researchers. CONCLUSIONS: The proposed selection mechanism provides insights that can be translated into research coaching programs as well as research policy models to optimize the introduction of high impact research at a broad scale among institutional and governmental agencies

Accuracy of Using Visual Identification of White Sharks to Estimate Residency Patterns

Determining the residency of an aquatic species is important but challenging and it remains unclear what is the best sampling methodology. Photo-identification has been used extensively to estimate patterns of animals' residency and is arguably the most common approach, but it may not be the most effective approach in marine environments. To examine this, in 2005, we deployed acoustic transmitters on 22 white sharks (Carcharodon carcharias) in Mossel Bay, South Africa to quantify the probability of detecting these tagged sharks by photo-identification and different deployment strategies of acoustic telemetry equipment. Using the data collected by the different sampling approaches (detections from an acoustic listening station deployed under a chumming vessel versus those from visual sightings and photo-identification), we quantified the methodologies' probability of detection and determined if the sampling approaches, also including an acoustic telemetry array, produce comparable results for patterns of residency. Photo-identification had the lowest probability of detection and underestimated residency. The underestimation is driven by various factors primarily that acoustic telemetry monitors a large area and this reduces the occurrence of false negatives. Therefore, we propose that researchers need to use acoustic telemetry and also continue to develop new sampling approaches as photo-identification techniques are inadequate to determine residency. Using the methods presented in this paper will allow researchers to further refine sampling approaches that enable them to collect more accurate data that will result in better research and more informed management efforts and policy decisions

Expert Panel Curation of 113 Primary Mitochondrial Disease Genes for the Leigh Syndrome Spectrum

OBJECTIVE: Primary mitochondrial diseases (PMDs) are heterogeneous disorders caused by inherited mitochondrial dysfunction. Classically defined neuropathologically as subacute necrotizing encephalomyelopathy, Leigh syndrome spectrum (LSS) is the most frequent manifestation of PMD in children, but may also present in adults. A major challenge for accurate diagnosis of LSS in the genomic medicine era is establishing gene-disease relationships (GDRs) for this syndrome with >100 monogenic causes across both nuclear and mitochondrial genomes. METHODS: The Clinical Genome Resource (ClinGen) Mitochondrial Disease Gene Curation Expert Panel (GCEP), comprising 40 international PMD experts, met monthly for 4 years to review GDRs for LSS. The GCEP standardized gene curation for LSS by refining the phenotypic definition, modifying the ClinGen Gene-Disease Clinical Validity Curation Framework to improve interpretation for LSS, and establishing a scoring rubric for LSS. RESULTS: The GDR with LSS across the nuclear and mitochondrial genomes was classified as definitive for 31/114 gene-disease relationships curated (27%); moderate for 38 (33%); limited for 43 (38%); and 2 as disputed (2%). Ninety genes were associated with autosomal recessive inheritance, 16 were maternally inherited, 5 autosomal dominant, and 3 X-linked. INTERPRETATION: GDRs for LSS were established for genes across both nuclear and mitochondrial genomes. Establishing these GDRs will allow accurate variant interpretation, expedite genetic diagnosis of LSS, and facilitate precision medicine, multi-system organ surveillance, recurrence risk counselling, reproductive choice, natural history studies and eligibility for interventional clinical trials. This article is protected by copyright. All rights reserved