scholarly journals Head-Down Tilt Bed Rest Studies as a Terrestrial Analog for Spaceflight Associated Neuro-Ocular Syndrome

2021 ◽  
Vol 12 ◽  
Author(s):  
Joshua Ong ◽  
Andrew G. Lee ◽  
Heather E. Moss
Keyword(s):  
United States ◽  
Experimental Model ◽  
Space Flight ◽  
Visual Loss ◽  
Small Sample Size ◽  
Bed Rest ◽  
The United States ◽  
Small Sample ◽  
Preventative Measures ◽  
Ocular Changes

Astronauts who undergo prolonged periods of spaceflight may develop a unique constellation of neuro-ocular findings termed Spaceflight Associated Neuro-Ocular Syndrome (SANS). SANS is a disorder that is unique to spaceflight and has no terrestrial equivalent. The prevalence of SANS increases with increasing spaceflight duration and although there have been residual, structural, ocular changes noted, no irreversible or permanent visual loss has occurred after SANS, with the longest spaceflight to date being 14 months. These microgravity-induced findings are being actively investigated by the United States' National Aeronautics Space Administration (NASA) and SANS is a potential obstacle to future longer duration, manned, deep space flight missions. The pathophysiology of SANS remains incompletely understood but continues to be a subject of intense study by NASA and others. The study of SANS is of course partially limited by the small sample size of humans undergoing spaceflight. Therefore, identifying a terrestrial experimental model of SANS is imperative to facilitate its study and for testing of preventative measures and treatments. Head-down tilt bed rest (HDTBR) on Earth has emerged as one promising possibility. In this paper, we review the HDTBR as an analog for SANS pathogenesis; the clinical and imaging overlap between SANS and HDTBR studies; and potential SANS countermeasures that have been or could be tested with HDTBR.

Trends in glassy cell cervical cancer in the United States from 1973-2015: Analysis based on SEER database.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e17502-e17502
Author(s):  
Anahat Kaur ◽  
Shuai Wang ◽  
Tarek N. Elrafei ◽  
Lewis Steinberg ◽  
Abhishek Kumar
Keyword(s):  
United States ◽  
Cervical Cancer ◽  
Overall Survival ◽  
Cell Carcinoma ◽  
Small Sample Size ◽  
Black Population ◽  
The United States ◽  
Small Sample ◽  
Cervix Uteri ◽  
Kaplan Meier

e17502 Background: Glassy cell carcinoma of cervix (GCCC) is a rare histological subtype of cervical cancer which has historically been associated with rapidly progressive disease, early development of metastases and overall poor prognosis. We attempt to define real-world trends in GCCC in the United States based on data from SEER (Surveillance, Epidemiology and End Results) database. Methods: We extracted data from the US National Cancer Institute's SEER 2018 dataset using ICD-O code for ‘Cervix Uteri Glassy Cell Carcinoma’. All patients who were diagnosed between 1973-2015 were included. Statistical analysis was done using SPSS 26. Kaplan Meier curve was used for survival analysis. Results: Data for a total of 57 patients with GCCC was available from 1975 to 2017. Median age at diagnosis was 38 years (range 30.5-44.5). Increased frequency of cases was noted in white females (77.2%) as compared to black population (22.2%). Most cases initially presented with localized or regional spread (47.4% and 40.4% respectively) with distant metastasis seen in only 10.5% patients. Data analysis revealed that 63.2% patients had Grade III poorly differentiated carcinoma, 66.7% received radiation therapy, 57.9% underwent chemotherapy and 59.6% had cancer direceted surgery performed. Calculated mean overall survival was 121.9 months. We were unable to calculate 5 year and 10 year median overall survival due to small sample size and censored data. Conclusions: GCCC is a rare histologic type of cervical cancer that presents at a younger age, is more frequently seen in white females and is commonly associated with localized or regional spread at time of initial presentation.[Table: see text]

An electrophoretic study of representatives of subgenus Diploxylon of Pinus

1989 ◽  
Vol 67 (6) ◽  
pp. 1750-1759 ◽  
Author(s):  
Roopa R. Karalamangala ◽  
Daniel L. Nickrent
Keyword(s):  
United States ◽  
Cluster Analysis ◽  
Phylogenetic Trees ◽  
Small Sample Size ◽  
The United States ◽  
Small Sample ◽  
Genetic Affinity ◽  
Electrophoretic Study ◽  
Isozyme Loci

Relationships among 14 taxa in subgenus Diploxylon of Pinus from Mexico and the United States were analyzed using 15 isozyme loci obtained from both frozen and fresh needle tissue. The phenogram obtained from cluster analysis of genetic distance values and phylogenetic trees implementing the distance Wagner procedure were in general agreement with classifications based on morphological features. Pinus leiophylla is genetically distinct from other species. Two groupings, one comprising P. oocarpa and P. pringlei and another comprising P. lawsonii and P. teocote, correspond to sections Serotinus and Teocote (sensu Martínez), respectively. Classification of the remaining eight taxa has varied, ranging from their placement in three, two, or only one section. Isozyme analysis resulted in a group that included P. cooperi, P. douglasiana, P. durangensis, P. michoacana, and P. montezumae, which suggests genetic affinity between Sections Pseudostrobus and Montezumae (sensu Martínez). This result corresponds more closely to the placement of these species in subsection Pseudostrobi. The distant relationship between P. engelmannii and the ponderosa pines may be anomalous (an artifact of small sample size) or may indicate greater genetic divergence than previously recognized.

Abstract WP105: A Practical Wake up Tpa Protocol at a United States Based Comprehensive Stroke Center Hub and Its Telestroke Spokes

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Navdeep S Sangha ◽  
Duy Le ◽  
Raeesa Dhanji ◽  
Denise Gaffney ◽  
David McCartney ◽  
...  
Keyword(s):  
United States ◽  
Small Sample Size ◽  
Statistical Significance ◽  
The United States ◽  
Small Sample ◽  
The Difference ◽  
Waking Up ◽  
Comprehensive Stroke Center ◽  
Stroke Center ◽  
Main Barrier

Background: IV tPA is established as an effective treatment for acute ischemic stroke. Currently it is endorsed up to 4.5 hours of last known well time by major guidelines. A randomized trial, WAKE-UP, displayed its safety and efficacy in patients who presented within 4.5 hours of waking up with their symptoms. Objective: To establish a practical tPA protocol for patients who wake up or are found with stroke symptoms at a large Comprehensive Stroke Center (CSC) and its 13 telestroke spokes (TS) based on the WAKE-UP trial. Methods: A wake up tPA protocol was created and given to all teleneurologists. Door to needle times (DTN) and reasons for no tPA were collected for 12 months post implementation and evaluated for differences between wake up (WU) and non-wake up (NW) patients. Results: 93 WU patients were identified; 23 at CSC and 70 at TS. 11 (47.8%) vs. 4 (5.7%) patients received tPA at CSC and TS, respectively. Median DTN was not significantly different for WU patients at CSC vs. TS (64 vs. 89 mins, p=0.54). Median DTN at CSC was shorter for NW vs. WU (37 vs. 64 mins; p=0.003). Similarly, median DTN at TS trended toward being shorter for NW vs. WU (44 vs. 89 mins; p=0.062). The reasons for no tPA at CSC were no mismatch found in 6 (50%), and MRI unavailability in 6 (50%); at TS were no mismatch found in 11 (16.6%), MRI unavailability in 54 (81,1%) and MRI was contraindicated in 1 (1.5%). Conclusion: Treating WU patients using a CSC Hub and TS model is feasible. DTN are longer for WU vs. NW. In the United States, MRI availability is the main barrier to WU tPA at both CSC and community hospitals. The difference between median DTN for WU between CSC and TS did not reach statistical significance, likely due to the small sample size.

scholarly journals Acid Suppressing Medication Use in Infants in the United States, 2002-2018

2020 ◽  
Author(s):  
michael e johansen
Keyword(s):  
United States ◽  
Logistic Regression ◽  
Sample Size ◽  
Small Sample Size ◽  
Medication Use ◽  
The United States ◽  
Demographic Characteristics ◽  
Small Sample ◽  
Uptake Inhibitors ◽  
Race Ethnicity

Introduction: I attempted to determine rates of use and associations with use of acid-suppressing medications in infants under 2 years old given these are not well studied. Methods: The 2002-2018 Medical Expenditure Panel Survey (MEPS) was used for the analysis. The survey is sponsored by the Agency of Healthcare Research and Quality and is conducted on households to be nationally representative of the non-institutionalized population of the United States. The survey is comprised of two overlapping panels that are each included in the survey for two years. Newborns and infants under 2 years old on December 31 of a survey year were included in the study. Additionally, adult men and women living in the same household between 18-45 years old were considered fathers and mothers of infants. Histamine2-receptor antagonists (H2RA) and proton pump inhibitors (PPI) were identified for infants. H2RA, PPIs, and anti-depressant (selective serotonin re-uptake inhibitors and serotonin-norepinephrine re-uptake inhibitors) were identified for parents. Sex, age (by month for child), race/ethnicity (White non-Hispanic, Black non-Hispanic, Hispanic, or other), region (Northeast, Midwest, South, and West), and poverty category were identified. Chi-squared and adjusted Wald tests were used to determine statistical significance with acid-suppressing medication use between 2010-2018. A multivariable logistic regression predicted any acid suppressing medication use with month of age and month of age2 as independent variables of use for the population between 2009-2018. The study was considered exempt by the OhioHealth Institutional Review Board. Survey weighting was included in all analyses. Results: The study included a total of 16,604 infants between 2002-2018. The rate of any acid suppressing medication increased between 2002-2004. H2RA use was more common than PPI use, especially after 2012. H2RA use appeared to increase after 2015. PPI use initially increased, but then remained relatively stable before appearing to decrease in 2015-2018. Ranitidine clearly had the most users of the H2RA, which was maintained throughout the study period. Lansoprazole had the most users among users of PPIs, but this decreased notably after 2010. Of the infants with a reported PPI, 34.0% (95%CI:23.6-46.3) also had an H2RA reported during the year. In total, 40.8% (95%CI:35.0-46.8) had only 1 reported fill of an acid suppresser. There were 8,075 infants under 2 years of age between 2010-2018. The rate of use was highest in infants between 4-11 months of age at the end of the survey year at 8.6% (95%CI:6.9-10.6). Acid-suppressing medication use was more common among infants in higher income families, White (non-Hispanic) race/ethnicity, infants with private health insurance, parents who reported acid-suppressing medication, maternal anti-depressant use, and certain regions of the country. Discussion: Between 6.9-10.6% of infants used an acid suppressing medication before their second birthday between 2010-2018, of which around 60% had multiple medication fills. It appears that there has been a small increases in use over the last few decades, of which ranitidine appears to be the medication driving the increase. Numerous socio-economic and demographic characteristics were associated with acid suppressing medication use. This study has numerous limitations, including potential under-reporting of acid-suppressing medications, an imperfect identification of parent, unreliable diagnoses (not included in the analysis), and a relatively small sample size. We opted not to run a multivariable logistic regression of socio-economic and demographic characteristics given concern for table 2 fallacy and relatively small sample size. Acid suppressing medication use was common in infants before their second birthday. Additional research should be conducted on efficacy and safety of these medications given the level of use and very low quality of available evidence.

Exploring the Relationship between Demographic Isolation and Professional Experiences of Black and Latinx Teachers

2021 ◽  
Author(s):  
Susan Kemper Patrick ◽  
Francisco Arturo Santelli
Keyword(s):  
Small Sample Size ◽  
The United States ◽  
Black Teachers ◽  
Small Sample ◽  
Continuous Measure ◽  
Professional Experiences ◽  
Workplace Experiences ◽  
Perceived Satisfaction ◽  
Ordinal Measure ◽  
Qualitative Work

Educational leaders throughout the United States have repeatedly emphasized the importance of increasing the number of Black and Latinx teachers in American schools. Prior qualitative work suggests that Black and Latinx teachers who are demographically isolated in their schools often report negative experiences. Drawing on theories of proportional representation in organizations, we use Tennessee statewide survey and administrative data to examine whether self-reported professional experiences of Black and Latinx teachers are different when they are demographically isolated. We estimate models using two measures of demographic isolation: a continuous measure and a theoretically generated ordinal measure. We find that, for Black teachers, the percentage of Black teachers in the school is positively associated with teachers’ perceived satisfaction and support and with the frequency of collaboration. There is also some evidence of threshold effects of demographic isolation for Black teachers, as Black teachers in schools in which at least 60% of fellow teachers are Black report significantly higher satisfaction and support than other Black teachers. Our models do not find any associations between isolation and professional experience for Latinx teachers, but a small sample size and lack of variation in demographic isolation among Latinx teachers makes it difficult to estimate these associations. Our findings suggest that both ordinal and continuous measures of demographic isolation may be useful when examining relationships between demographic isolation and workplace experiences. Because we study factors linked to turnover in prior research, these analyses can contribute to the broader discussion about the retention of Black and Latinx teachers.

scholarly journals Dependence in the Banking Sector of the United States and Mexico: A Copula Approach

2021 ◽  
Vol 16 (TNEA) ◽  
pp. 1-23
Author(s):  
Christian Bucio Pacheco ◽  
Luis Villanueva ◽  
Raúl de Jesús Gutiérrez
Keyword(s):  
United States ◽  
Stock Prices ◽  
Banking Sector ◽  
Tail Dependence ◽  
The United States ◽  
Small Sample ◽  
High Dependency ◽  
The Us ◽  
Rolling Windows ◽  
Main Banks

The objective of this work is to estimate the patterns of dependence between the yields of the stock prices of the main banks of the United States (US) and Mexico. We estimate the patterns of absolute dependence and tail dependence through copulas of the Archimedean family and the use of rolling windows of 245 days. The data employed come from the daily share prices at closing from January 2, 2015, to December 31, 2020, for seven banks. Our results show that: i) there are patterns of high dependence among the main banks in the US, ii) there are patterns of very low dependence among the main banks in the US and Mexico, and iii) there are patterns of low dependence among the main banks in Mexico. These results have several implications, among them that the high-dependency patterns obtained among major US banks limit the joint selection of these US bank equity assets in an investment portfolio. Although this paper focuses on a small sample of banks, they represent an important portion of the banking sector in both countries. Given the limited literature on this subject in Mexico, our paper contributes to expanding this literature with a novel approach.

scholarly journals Private space flights: legal regulation in the United States

2020 ◽  
pp. 382-388
Author(s):  
Оleksandr Zadorozhny
Keyword(s):  
United States ◽  
Space Flight ◽  
The United States ◽  
Legal Regulation ◽  
Economic Feasibility ◽  
Gradual Transition ◽  
Significant Shift ◽  
Private Space ◽  
Space Flights ◽  
The Usa

The emergence of demand for space travel, the emergence of commercial enterprises and travel agencies in the space industry,the development of vehicles designed exclusively for transporting tourists into space – all this suggests that space may soon turn froma scientific object into a common destination. Therefore, today the legal regulation of private space flights is a promising issue, giventhat there is no such legislation in Ukraine. We turn to the analysis of the legislation of the United States of America to assess whatarray of regulations we will have to master if we want to develop private space flights at home.A private space flight is a space flight or development of space flight technology that is conducted and paid for by an entity otherthan a government agency. Depending on the purpose, private space flights are divided into flights for the purpose of transportation ofcargoes, and flights within the framework of space tourism.The article presents an overview and analysis of the legislation of the USA regulating private space flights, in particular, flightsfor the purpose of transportation of cargoes, and flights in the framework of space tourism. The author highlights a chronological formationof the commercialization of space, which clearly shows the gradual transition of the United States from a complete reluctanceto allow private space flights to the recognition of the indisputable economic feasibility of such activities. A significant shift in this areahas taken place since 2015, when five directives on space policy, the National Space Strategy and orders on the exploration, extractionand use of space resources were adopted.The author analyzes the main sources of space law in the United States. It was found that mostly, the legislation does not keepup with innovations in the commercialization of space, thus, there is a situation when first comes a relationship (flight of a tourist orcargo into space), and then – the legislative regulation of such relations.

Impact of race on biomarker testing among HER2- advanced breast cancer (ABC) patients (pts) in the United States: Results from a real-world study.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 10598-10598
Author(s):  
Reshma L. Mahtani ◽  
Alexander Niyazov ◽  
Katie Lewis ◽  
Lucy Massey ◽  
Alex Rider ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Targeted Therapies ◽  
Small Sample Size ◽  
The United States ◽  
Small Sample ◽  
Access To Treatment ◽  
History Of ◽  
Biomarker Testing ◽  
Abstract Data ◽  
The Impact

10598 Background: African Americans (AA) have the highest breast cancer (BC) mortality rate. Access to treatment is a known contributing factor. In the past 4 years, several targeted therapies for HER2- BC have become available which require testing for specific biomarkers. This study assessed the impact of race on biomarker testing rates in HER2- ABC pts receiving treatment in the US. Methods: Oncologists were recruited to abstract data from medical charts for the next 8-10 pts receiving treatment with HER2- ABC during Sept 2019-Apr 2020. Pts records were stratified by race and categorized into 3 mutually exclusive cohorts [White/Caucasian (White), AA, Other]. The other race cohort was excluded from this analysis due to small sample size. Differences in pt demographics/clinical characteristics were analyzed via Fisher’s exact tests. Testing rates for actionable biomarkers (i.e. BRCA1/2, PIK3CA, PD-L1) were compared between White and AA pts utilizing logistic regressions controlling for age, known family history of a BRCA-related cancer, hormone receptor (HR) status and practice setting (academic vs. community). Further analyses by age will be presented. Results: This analysis included 378 pts records, provided by 40 oncologists. Mean age was 64 years; 77% had HR+/HER2- ABC; 20% had advanced triple negative breast cancer (TNBC), 3% had ABC with an unknown HR status. Compared to White pts, AA pts were significantly more likely to have advanced TNBC (27% vs. 18%, p<0.05). Compared to White pts, AA pts had significantly lower BRCA1/2 mutation (mut) testing rates (Table). Numerically lower rates of PIK3CAmut and PD-L1 testing were observed among AA pts (Table). BRCA1/2mut positivity rate (germline [g] and/or somatic [s]) was higher among AA vs. White pts (30% vs. 22%). Positivity rate for PIK3CAmut was lower for AA vs. White pts (8% vs. 11%). Conclusions: A higher than expected BRCA1/2mut positivity rate was observed than previously reported in the literature. This is likely because this analysis included s BRCA1/2mut and represented a high risk pt population. Across all biomarkers assessed, AA pts had lower testing rates than White pts. This suggests racial disparities in testing rates of actionable biomarkers. Consistent with guidelines, and with the increased availability of targeted therapies, focused efforts should be developed to increase biomarker testing in AA pts. Funding: Pfizer Biomarker Testing Rates by Race.[Table: see text]

Manned Space Flight Navigation Techniques

1963 ◽  
Vol 16 (4) ◽  
pp. 449-461
Author(s):  
Richard C. Henry
Keyword(s):  
United States ◽  
Space Flight ◽  
The United States ◽  
Deutsche Gesellschaft ◽  
Manned Space Flight ◽  
Manned Space

This paper (which was presented at a meeting of the Deutsche Gesellschaft für Ortung und Navigation held in Berlin in April 1963) describes the navigational techniques of manned space flight as they are at present conceived by the National Aeronautics and Space Administration in the United States. Although the paper is written in a more or less popular form, it should be of wide interest to navigators in showing the lines along which thought on this subject is developing, in one country at least.

Sign in / Sign up

Export Citation Format

Share Document