cssi/SciSciGPT-SciSciNet huggingface dataset:
The anatomy of large-scale motion in atmospheric boundary layers

The atmospheric boundary layer is the level of the atmosphere where all human activities occur. It is a layer characterized by its turbulent flow state, meaning that the velocity, temperature and scalar concentrations fluctuate over scales that range from less than a millimetre to several kilometres. It is those fluctuations that make dispersion of pollutants and transport of heat, momentum as well as scalars such as carbon dioxide or cloud-condensation nuclei efficient. It is also the layer where a ‘hand-shake’ occurs between activities on the land surface and the climate system, primarily due to the action of large energetic swirling motions or eddies. The atmospheric boundary layer experiences dramatic transitions depending on whether the underlying surface is being heated or cooled. The existing paradigm describing the size and energetics of large-scale and very large-scale eddies in turbulent flows has been shaped by decades of experiments and simulations on smooth pipes and channels with no surface heating or cooling. The emerging picture, initiated by A. A. Townsend in 1951, is that large- and very large-scale motions appear to be approximated by a collection of hairpin-shaped vortices whose population density scales inversely with distance from the boundary. How does surface heating, quintessential to the atmospheric boundary layer, alter this canonical picture? What are the implications of such a buoyancy force on the geometry and energy distribution across velocity components in those large eddies? How do these large eddies modulate small eddies near the ground? Answering these questions and tracking their consequences to existing theories used today to describe the flow statistics in the atmospheric boundary layer are addressed in the work of Salesky & Anderson (J. Fluid Mech., vol. 856, 2018, pp. 135–168). The findings are both provocative and surprisingly simple.
UNIT 13.9 Gene Delivery to the Airway

This unit describes generation of and gene transfer to several commonly used airway models. Isolation and transduction of primary airway epithelial cells are first described. Next, the preparation of polarized airway epithelial monolayers is outlined. Transduction of these polarized cells is also described. Methods are presented for generation of tracheal xenografts, as well as both ex vivo and in vivo gene transfer to these xenografts. Finally, a method for in vivo gene delivery to the lungs of rodents is included. Methods for evaluating transgene expression are given in the support protocols. Curr. Protoc. Hum. Genet. 78:13.9.1-13.9.41. © 2013 by John Wiley & Sons, Inc. Keywords: genetics and genomics; gene therapy
The Impact of Age and Adjuvant Chemotherapy Modifications on Survival Among Black Women With Breast Cancer.

Abstract Background Black women receive less relative dose intensity with more dose reductions and early chemotherapy cessation compared with White women. Adding further risk, older patients with breast cancer are most at risk for treatment modifications; however, it is unclear if this remains true for Black patients. Furthermore, the clinical implications of treatment modifications and delays on survival is uncertain, particularly in Black patients. Patients and Methods The purpose was to investigate whether age was a moderator for the association between treatment modifications (dose held, dose delayed, and early cessation) and overall survival and disease-free survival (DFS) in Black women with breast cancer using a retrospective cohort study of patients with early stage breast cancer treated with adjuvant chemotherapy. Results Across the entire sample (n = 115), 37.4% (n = 43) of patients experienced a treatment modification. There was a significant interaction between age group and held dose for DFS (P = .026). Specifically, those diagnosed at 55 years of age and older, who had doses of chemotherapy held, experienced worse DFS compared with those who did not (hazard ratio, 4.185; 95% confidence interval, 1.187-14.75). In contrast, there was no difference in DFS between those who did and did not have doses held in patients diagnosed below 55 years of age (hazard ratio, 0.626; 95% confidence interval, 0.177-2.218). Conclusion In this study, Black women receiving adjuvant chemotherapy for treatment of early stage breast cancer had roughly equal treatment modifications across age groups. However, held doses of chemotherapy in older Black patients were associated with worse DFS. Age may impact clinical outcomes seen with adjuvant chemotherapy treatment modifications.
Emergency Department Visit Within One Year Prior to Elective Total Joint Arthroplasty Is Predictive of Postoperative Return to Emergency Department Within 90 Days.

Abstract Background The Comprehensive Care for Joint Replacement Model, developed by Centers for Medicare and Medicaid Services, aims to improve the quality of joint replacement. Metrics including emergency room visit rates after primary total knee and total hip arthroplasty (TKA and THA) are of particular interest. The purpose of this study is to determine if preoperative emergency department (ED) visits are predictive of postoperative ED visits among patients undergoing elective THA or TKA. Methods In a retrospective analysis of 6996 patients who underwent elective primary arthroplasty (2453 hips, 4543 knees), we identified all patients who had an ED visit from up to 1 year prior to their surgical date to 90 days after. We assessed if preoperative visit frequency or temporality is predictive of a return to the ED visit within 90 days. Results TKA and THA patients with a single preoperative ED visit had an odds ratio of 1.9 and 2.0, respectively, of returning to the emergency room postoperatively (P Conclusion Presentation to the ED is common prior to total joint arthroplasty and is predictive of a postoperative visit within 90 days. Increasing preoperative visit frequency further increases a patient’s risk of a postoperative visit within 90 days.
Effects of Environmental Changes on Emergency Rooms Visits for Adult Sickle Cell Disease

Background: Acute pain crises from vaso occlusive episodes are major cause of morbidity, hospitalization and emergency room visits for patients with sickle cell disease. Major causes of acute painful crises have been attributed to dehydration, infections and fever. Weather change has also been attributed as one of the major cause of acute pain crises by physicians and patients. Data on effects of environmental changes on acute pain crises in patients with sickle cell disease is mixed. Here we report our investigation to see if number of emergency room visits for adult patients with SCD were associated with environmental changes. Method: At our hematology clinic we take care of around 300 adult patients with SCD and we have on average around 11,000 emergency room visit per years from these patients. Electronically from EHR (Electronic health Record), we pulled out data on number of emergency room visit every day for adult patient with SCD in year 2015.We also gathered data on daily environmental changes from a national weather website for the year 2015 and collected data on daily temperature changes, humidity and precipitation/rain in our area. We did analysis to see if there was any correlation between the weather changes and emergency room visit. Results: As shown in graphs below, there was no correlation between the number of ER visits and weather changes in adult patient with SCD. Conclusion: Our analysis showed that there was no correlation between number of ER visit for adult patient with SCD and weather changes like -temperature, humidity and precipitation/rain. ER Visits and Precipitation ER visits, temperature and humidity Download : Download high-res image (112KB) Download : Download full-size image Download : Download high-res image (98KB) Download : Download full-size image Disclosures No relevant conflicts of interest to declare.
Correlation of molecular and morphologic effects of thermoembolization in a swine model using mass spectrometry imaging

Hepatocellular carcinoma is a growing worldwide problem with a high mortality rate. This malignancy does not respond well to chemotherapy, and most patients present late in their disease at which time surgery is no longer an option. Over the past three decades, minimally invasive methods have evolved to treat unresectable disease and prolong survival. Intra-arterial embolization techniques are used for large or multiple tumors but have distressingly high levels of local recurrence and can be costly to implement. A new method called thermoembolization was recently reported, which destroys target tissue by combining reactive exothermic chemistry with an extreme local change in pH and ischemia. Described herein are experiments performed using this technique in vivo in a swine model. A microcatheter was advanced under fluoroscopic guidance into a branch of the hepatic artery to deliver a targeted dose of dichloroacetyl chloride dissolved in ethiodized oil into the liver. The following day, the animals were imaged by computed tomography and euthanized. Assessing the reaction product distribution and establishing a correlation with the effects are important for understanding the effects. This presented a significant challenge, however, as the reagent used does not contain a chromophore and is not otherwise readily detectable. Mass spectrometry imaging was employed to determine spatial distribution in treated samples. Additional insights on the biology were obtained by correlating the results with histology, immunohistochemistry, and immunofluorescence. The results are encouraging and may lead to a therapy with less local recurrence and improved overall survival for patients with this disease.
On the Impossibility of Black-Box Transformations in Mechanism Design

A fundamental question in algorithmic mechanism design is whether any approximation algorithm for a single-parameter social-welfare maximization problem can be turned into a dominant-strategy truthful mechanism for the same problem (while preserving the approximation ratio up to a constant factor). A particularly desirable type of transformations—called black-box transformations—achieve the above goal by only accessing the approximation algorithm as a black box.
Clinical factors associated with baseline history of atrial fibrillation and subsequent clinical outcomes following initial implantable cardioverter-defibrillator placement.

Author(s): Giancaterino, Shaun; Nishimura, Marin; Birgersdotter-Green, Ulrika; Hoffmayer, Kurt S; Han, Frederick T; Raissi, Farshad; Ho, Gordon; Krummen, David; Feld, Gregory K; Hsu, Jonathan C | Abstract: Atrial fibrillation (AF) is frequently present in patients with heart failure (HF) and an implantable cardioverter-defibrillator (ICD). This study aims to identify clinical factors associated with a baseline history of AF in ICD recipients, and compares subsequent clinical outcomes in those with and without a baseline history of AF.We studied 566 consecutive first-time ICD recipients at an academic center between 2011 and 2018. Logistic regression multivariable analysesnwere used to identify clinical factors associated with a baseline history of AF at the time of ICD implant. Cox-proportional hazard regression models were constructed for multivariate analysis to examine associations between a baseline history of AF with subsequent clinical outcomes, including ICD therapies, HF readmission, and all-cause mortality.Of all patients, 201 (36%) had a baseline history of AF at the time of ICD implant. In multivariate analyses, clinical factors associated with a baseline history of AF included hypertension, valvular heart disease, body weight, PR interval, and serum creatinine level. After multivariate adjustment for potential confounders, a baseline history of AF was associated with an increased risk of anti-tachycardia pacing (HRn=n1.84, 95% CIn=n1.19-2.85, Pn=n.006), appropriate ICD shocks (HRn=n1.80, 95% CIn=n1.05-3.09, Pn=n.032), and inappropriate ICD shocks (HRn=n3.72, 95% CIn=n1.7-7.77, Pn=n.0001), but not other adverse outcomes.Among first-time ICD recipients, specific clinical characteristics were associated with a baseline history of AF at the time of ICD implant. After adjustment for potential confounders, a baseline history of AF was associated with a higher risk of all ICD therapies in follow-up.
Specialization versus generalization in pathology

Specialization versus generalization in pathology As medical knowledge increases and deepens, there is a tendency to specialize. This is especially visible in the larger specialties such as internal medicine and surgery, but it also occurs in smaller fields such as dermatology. The situation is a little different in pathology as there are many more (sub)specializations which causes special problems. Advantages of specialization are, amongst others, increased knowledge and better communication with clinical colleagues. In this paper, the disadvantages - losing sight of the bigger picture, tunnel vision and having problems finding new pathologists who have all the proper qualifications - are weighed against the advantages. Although specialization is probably inevitable, there will still be a need for a generalist, especially when it comes to medical education and filling in when a specialist colleague leaves.
Libertella y Borges, o las patografías de Menard

Este trabajo busca subrayar algunos de los puntos de contacto y de discrepancia entre las obras de Hector Libertella y Jorge Luis Borges. En una primera parte se enumeran y comentan algunas de las caracteristicas generales de la obra de Libertella y de lo que la critica ha dicho sobre la relacion entre su obra y la de Borges. En una segunda parte, se analizan los cuatro ensayos principales que Libertella le dedicara a Borges y se complementan algunas de las ideas que propone Libertella con un estudio de las estrategias de autofiguracion del Borges de la poesia posterior a los anos cincuenta.
Obesity and the Receipt of Prescription Pain Medications in the US.

Little is known about disparities in pain treatment associated with weight status despite prior research on weight-based discrepancies in other realms of healthcare and stigma among clinicians. To investigate the association between weight status and the receipt of prescription analgesics in a nationally representative sample of adults with back pain, adjusting for the burden of pain. Cross-sectional analyses using the Medical Expenditure Panel Survey (2010–2017). Five thousand seven hundred ninety-one civilian adults age ≥ 18 with back pain. We examine the odds of receiving prescription analgesics for back pain by weight status using logistic regression. We study the odds of receiving (1) any pain prescription, (2) three pain prescription categories (opioid only, non-opioid only, the combination of both), and (3) opioids conditional on having a pain prescription. The odds of receiving pain prescriptions increase monotonically across weight categories, when going from normal weight to obesity II/III, despite adjustments for the burden of pain. Relative to normal weight, higher odds of receiving any pain prescription is associated with obesity I (OR = 1.30 [95% CI = 1.04–1.63]) and obesity II/III (OR = 1.72 [95% CI = 1.36–2.18]). Obesity II/III is also associated with higher odds of receiving opioids only (OR = 1.53 [95% CI = 1.16–2.02]), non-opioids only (OR = 1.77 [95% CI = 1.21–2.60]), and a combination of both (OR = 2.48 [95% CI = 1.44–4.29]). Obesity I is associated with increased receipt of non-opioids only (OR = 1.55 [95% CI = 1.07–2.23]). Conditional on having a pain prescription, the odds of receiving opioids are comparable across weight categories. This study suggests that, relative to those with normal weight, adults with obesity are more likely to receive prescription analgesics for back pain, despite adjustments of the burden of pain. Hence, the possibility of weight-based undertreatment is not supported. These findings are reassuring because individuals with obesity generally experience a higher prevalence of back pain. The possibility of over-treatment associated with obesity, however, may warrant further investigation.
An Exhaustive Multiple Knockout Approach to Understanding Cell Wall Hydrolase Function in Bacillus subtilis

Most bacteria are surrounded by their cell wall, a highly crosslinked protective envelope of peptidoglycan. To grow, bacteria must continuously remodel their wall, inserting new material and breaking old bonds. Bond cleavage is performed by cell wall hydrolases, allowing the wall to expand. Understanding the functions of individual hydrolases has been impeded by their redundancy: single knockouts usually present no phenotype. We used an exhaustive multiple-knockout approach to determine the minimal set of hydrolases required for growth in Bacillus subtilis. We identified 42 candidate cell wall hydrolases. Strikingly, we were able to remove all but two of these genes in a single strain; this "{Delta}40" strain shows a normal growth rate, indicating that none of the 40 hydrolases are necessary for cell growth. The {Delta}40 strain does not shed old cell wall, demonstrating that turnover is not essential for growth. The remaining two hydrolases in the {Delta}40 strain are LytE and CwlO, previously shown to be synthetically lethal. Either can be knocked out in {Delta}40, indicating that either hydrolase alone is sufficient for cell growth. Environmental screening and zymography revealed that LytE activity is inhibited by Mg2+ and that RlpA-like proteins may stimulate LytE activity. Together, these results demonstrate that the only essential function of cell wall hydrolases in B. subtilis is to enable cell growth by expanding the wall and that LytE or CwlO alone is sufficient for this function. These experiments introduce the {Delta}40 strain as a tool to study hydrolase activity and regulation in B. subtilis. IMPORTANCEIn order to grow, bacterial cells must both create and break down their cell wall. The enzymes that are responsible for these processes are the target of some of our best antibiotics. Our understanding of the proteins that break down the wall - cell wall hydrolases - has been limited by redundancy among the large number of hydrolases many bacteria contain. To solve this problem, we identified 42 cell wall hydrolases in Bacillus subtilis and created a strain lacking 40 of them. We show that cells can survive using only a single cell wall hydrolase; this means that to understand the growth of B. subtilis in standard laboratory conditions, it is only necessary to study a very limited number of proteins, simplifying the problem substantially. We additionally show that the {Delta}40 strain is a research tool to characterize hydrolases, using it to identify 3 helper hydrolases that act in certain stress conditions.
Highly multiplexed rapid DNA detection with single-nucleotide specificity via convective PCR in a portable device.

Assays for the molecular detection of nucleic acids are typically constrained by the level of multiplexing (this is the case for the quantitative polymerase chain reaction (qPCR) and for isothermal amplification), turnaround times (as with microarrays and next-generation sequencing), quantification accuracy (isothermal amplification, microarrays and nanopore sequencing) or specificity for single-nucleotide differences (microarrays and nanopore sequencing). Here we show that a portable and battery-powered PCR assay performed in a toroidal convection chamber housing a microarray of fluorescently quenched oligonucleotide probes allows for the rapid and sensitive quantification of multiple DNA targets with single-nucleotide discrimination. The assay offers a limit of detection of 10 DNA copies within 30 min of turnaround time and a dynamic range spanning 4 orders of magnitude of DNA concentration, and we show its performance by detecting 20 genomic loci and 30 single-nucleotide polymorphisms in human genomic DNA samples, and 15 bacterial species in clinical isolates. Portable devices for the fast and highly multiplexed detection of nucleic acids may offer advantages in point-of-care diagnostics. A portable PCR assay performed in a toroidal convection chamber housing an array of fluorescently quenched oligonucleotide probes allows for the rapid quantification of multiple DNA targets with single-nucleotide discrimination.
Innovations in virtual education for clinical and simulation learning

Abstract The global impact of COVID-19 forced nursing education to provide an alternative for scheduled clinical experiences during the Spring and Fall of 2020. Many programs selected the pre-packaged, web-based solutions at the onset of the pandemic due to the uncertainty and recommendation of social distancing. Clinical and simulation faculty began to look for educational alternatives to provide meaningful learning experiences that more closely replicated clinical learning because students expressed displeasure with the asynchronous web-based options. This article outlines how an innovative partnership between clinical faculty, simulation faculty, and the Theatre Department modified an in-person simulation activity designed for groups of two students into a web-based “clinical” experience that included the assigned clinical faculty, eight nursing students, and one simulated patient. This active learning strategy was able to meet the course objectives, required little additional resources, and most importantly, underwent positive evaluation by the weary, screen-based learners.
Estimating the Proportion of Essential Tremor and Parkinson’s Disease Patients Referred for Deep Brain Stimulation: Five-Year Data from Columbia University Medical Center (2009-2014) (P4.146)

OBJECTIVE: To estimate the proportion of essential tremor (ET) and Parkinson’s disease (PD) patients referred for deep brain stimulation (DBS) surgery. BACKGROUND: DBS has become an important treatment for patients with ET and PD. Surprisingly, there is no data on the actual proportion of such patients referred for this procedure. DESIGN/METHODS: A search was conducted of the computerized billing database of the Center for Parkinson’s Disease and Other Movement Disorders, Columbia University Medical Center (CUMC) for patients who received the diagnostic codes 333.1 (tremor) and/or 332.0 (PD) in the period from January 1, 2009 to May 8, 2014. One-hundred electronic charts were reviewed for each diagnostic code to validate the ET and PD diagnoses. The proportion of patients who had been followed by a doctor at the Center and who had undergone DBS for these diagnoses was then estimated. RESULTS: One-hundred-eighty-six patients underwent DBS in this time period; 105 were excluded because they were referred directly from outside the Center for DBS evaluation. The remaining 81 (52 PD, 14 ET, 11 ET+PD, 4 other) were followed at the Center prior to the DBS referral and surgery. The total number of patients who received the diagnostic codes 333.1 and 332.0 was 1,198 and 5,191 respectively. The validity of the ET and PD diagnoses, based on chart review, was 75[percnt] and 88[percnt]; hence the above values were adjusted to 898 and 4,568. The proportion of ET patients referred for DBS was 25/898 (2.78[percnt], 95[percnt] confidence interval [CI] = 1.84 - 4.14[percnt]) and for PD was 63/4,568 (1.38[percnt], 95[percnt] CI = 1.07 - 1.77[percnt]). The difference was significant (p = 0.002). CONCLUSIONS: At our tertiary center, approximately 1-in-35 to 1-in-72 ET or PD patients were referred for DBS surgery. In this sample, the proportion with ET was higher than that of PD. Disclosure: Dr. Kestenbaum has nothing to disclose. Dr. Louis has nothing to disclose.
Some remarks on polynomial time isomorphisms

Joseph and Young [JY-85] hypothesized that the Berman-Hartmanis isomorphism conjecture fails if there exists a k-completely creative set in NP with no p-invertible p-completely productive functions. We verify this hypothesis for DEXT based on new results of p-creative sets in [Wan-89]. In particular, we prove that the isomorphism conjecture for DEXT fails iff there is a p-creative set for P in DEXT with no p-invertible p-productive functions.
GETTING FROM HERE TO THERE IN REDISTRICTING REFORM

This symposium has been largely devoted to whether and how we ought to reform our districting process. Today I want to talk about a related but often neglected question: if we are serious about reform, how do we make it happen? I will thus set aside some of the important normative and practical questions associated with what kind of redistricting reform we should pursue and focus instead on how to get from here to there. As we think about getting redistricting reform passed, we ought to ask ourselves three questions. First, what should our goals be during the 2010 cycle? Second, moving from principle to practice, what specifically can we do to promote reform during this period? Third, if we succeed in getting some traction with reform post-2010, what kind of reform proposals should we push?
Stickelberger Ideals and Bernoulli Distributions

The study of ideal classes or units in cyclotomic fields, or number fields (Iwasawa, Leopoldt), of divisor classes on modular curves (e.g., as in [KL]), of higher K-groups (Coates-Sinnott [Co 1], [Co 2], [C-S]) has led to purely algebraic theorems concerned with group rings and certain ideals, formed with Bernoulli numbers (somewhat generalized, as by Leopoldt). Such ideals happen to annihilate these groups, but in many cases it is still conjectural that the groups in question are isomorphic to the factor group of the group ring by such ideals.
Diagnosis of Left Ventricular Hypertrophy in the Presence of Left Anterior Fascicular Block: A Reexamination of the 2009 AHA/ACCF/HRS Guidelines

Background The 2009 “AHA/ACCF/HRS Recommendations for Standardization and Interpretation of the Electrocardiogram” state that left ventricular hypertrophy (LVH) criteria that include R-wave amplitude in leads I and aVL are not likely reliable in the presence of left anterior fascicular block (LAFB). This statement was referenced to three relatively small studies. The present study reexamines the utility of selected electrocardiographic (ECG) criteria for LVH in the presence of LAFB. Methods We identified 185 ECG tracings with LAFB from patients in whom echocardiogram had been performed within 30 days of the ECG. These ECGs were evaluated for the presence of selected LVH criteria: (1) Sokolow index (R-wave-aVL > 11 mm); (2) Cornell criteria (R-wave-aVL + S-wave-V3 > 28 mm in men (>20 mm in women); (3) Gertsch criterion (S-wave-III + (R + S) maximal precordial >30 mm); and (4) Bozzi criterion (SV1 or SV2 + (RV6 + SV6) > 25 mm). The “gold standard” for LVH was left ventricular mass index on echocardiogram. Results Although the aVL-based LVH criteria demonstrated lower sensitivity (45–68%) and a trend toward higher specificity (67–81%) compared to non-aVL-based criteria, the four studied criteria demonstrated similar diagnostic accuracy. Conclusions In the presence of LAFB, the aVL-based Sokolow index and Cornell criteria, which were excluded from 2009 multisociety ECG guidelines, identify LVH with similar diagnostic accuracy as the non-aVL-based criteria that were included. Moreover, they are easier to calculate and are included in some of the computer-assisted ECG interpretation software presently in use. Their exclusion from the 2009 guidelines was unnecessary.
Response of the circulation of pregnant sheep to angiotensin and norepinephrine before and after dexamethasone

Abstract We studied the vascular reactivity of the systemic and uterine circulations of six pregnant sheep. We placed catheters in a maternal carotid artery and a jugular vein, and then implanted an electromagnetic flow transducer around the uterine artery of the pregnant horn. After allowing 3 days for recovery from anesthesia and operation, we measured mean arterial blood pressure, heart rate, uterine blood flow, and calculated uterine vascular resistance, then separately infused angiotensin and norepinephrine in each ewe at the rate that produced a 20 torr pressor response. Dexamethasone, 0.2 mg. per kilogram of body weight, was then injected intravenously daily for 2 to 4 days. On the day following the final injection of dexamethasone, we separately infused angiotensin and norepinephrine at a rate that, before steroid treatment, produced a 20 torr pressor response. Administration of dexamethasone for 2 to 4 days did not change mean arterial blood pressure, heart rate, uterine blood flow, or uterine vascular resistance. Prior to steroid treatment, angiotensin increased blood pressure, decreased heart rate, but had no consistent effect on uterine blood flow or uterine vascular resistance; norepinephrine increased blood pressure without chenging heart rate, decreased uterine blood flow, and increased uterine vascular resistance. The changes produced by angiotensin and norepinephrine were the same after dexamethasone treatment. These studies indicate that dexamethasone does not influence systemic and uterine vascular reactivity during normal sheep pregnancy.
Mechanisms of change in the development of mathematical reasoning.

Publisher Summary This chapter describes the mechanisms of change in the development of mathematical reasoning and focuses on the change mechanisms that apply in the development of mathematical reasoning. Mathematical reasoning is a useful domain to study change mechanisms because many changes in people's mathematical thinking and problem solving can be readily observed and because such changes are amenable to experimental investigation. Understanding change in the domain of mathematical reasoning may prove useful for designing optimal instruction and for understanding mathematics learning difficulties. This chapter reviews research regarding two classes of change mechanisms that have been proposed for applying in the domain of mathematical reasoning: “mechanisms that involve reciprocal relations between knowledge of problem-solving procedures and knowledge of concepts,” and “mechanisms that involve expressing knowledge in speech and gestures.” These two classes of mechanisms are not the only ones that have been proposed for applying in the development of mathematical reasoning.
Two-Stage Alpha-Beta-Gamma-Lambda Estimator For Tracking Constant Speed, Maneuvering Targets

The two-stage Alpha-Beta-Gamma-Lambda estimator is proposed as an alternative to adaptive gain versions of the Alpha-Beta and Alpha-Beta-Gamma filters for tracking constant speed, maneuvering targets. This two-stage estimator is the two-stage Alpha-Beta-Gamma estimator with the kinematic constraint for constant speed targets included in the second stage. The purpose of this paper is to accomplish constant gain, variable dimension filtering for constant speed, maneuvering targets with the two-stage Alpha-Beta-Gamma-Lambda estimator which is derived from a two-stage Kalman estimator. A procedure for filter parameter selection is also given along with a technique for maneuver response. Simulation results are given to demonstrate the benefits of including the kinematic constraint.
Galactomuramic Acid CHEMICAL SYNTHESIS, PROPERTIES, ASSAY, AND SURVEY IN SEVERAL BACTERIAL SPECIES

Abstract Synthetic d-galacto- and d-glucomuramic acids were prepared from the condensation of l-α-chloropropionic acid with benzyl-2-acetamido-4,6-O-benzylidene-2-deoxy-α-d-galacto- or glucopyranoside. The configuration of the d(-) lactate moiety (i.e. 3-O-(d-1-carboxyethyl)-) obtained by alkaline β elimination, was proven by use of specific d(-)- and l(+)-lactic acid dehydrogenases. Standard methods commonly used for the detection of muramic acid were found to be unsuitable for distinction between the two products. Thus, although the Barker and Summerson, Morgan-Elson, Park-Johnson, and Rondle-Morgan tests were shown to detect both gluco and galacto epimers of muramic acid (color yields differed slightly), such colorimetric assays could not differentiate between the analogues. Ionophoresis did not distinguish the forms of muramic acid, and thin layer chromatography was found to be suitable for distinction only under carefully controlled conditions. Cation exchange chromatography, according to Gardell, was used successfully in the separation of the glucomuramic and galactomuramic acids, but it was found that glucosamine co-elutes with galactomuramic acid. The most rapid and precise detection method was that in which a commercial amino acid analyzer was used. Detection of nanomole quantities of material was possible. The muramic acid content of 16 bacterial species was determined. Only the glucomuramic acid analogue was found.
MR assessment of radiation-induced blood-brain barrier permeability changes in rat glioma model.

PURPOSE To assess the potential of a T1-weighted, gadolinium-enhanced MR technique for quantifying radiation-induced changes of blood-brain barrier permeability in a model of stereotactically implanted intracerebral gliomas in rats. METHODS We calculated the gadolinium blood-to-tissue transport coefficient for gadopentetate dimeglumine from signal intensities in sequential MR images in nine control animals that were not irradiated and in five and three animals that had received 2500 cGy and 1500 cGy whole-brain irradiation, respectively, at 2 days before imaging. RESULTS The average blood-to-tissue transport coefficient values were 9.76 mL.kg-1.min-1 in the control group, 23.41 mL.kg-1.min-1 in the 2500 cGy group, and 25.63 mL.kg-1.min-1 in the 1500-cGy group. Blood-to-tissue transport coefficients were significantly higher after irradiation, indicating increased radiation-induced blood-brain barrier permeability. Similar increased blood-brain barrier leakiness in brain tumors after high-dose irradiation has been shown by previous nuclear medicine studies using quantitative autoradiography. CONCLUSION Contrast-enhanced dynamic MR of brain gliomas is a sensitive method to document radiation-induced blood-brain barrier breakdown. Quantitative gadolinium-enhanced MR may become a useful tool for the management of patients with brain tumors undergoing radiation therapy.
Enrollment and monitoring of women in post-approval studies for medical devices mandated by the Food and Drug Administration.

Abstract Background: Disease presentation, prevalence, and treatment effects vary by sex, thus it is important to ensure adequate participation of both sexes in medical device post-approval studies (PAS). Methods: The goals of this study were to determine the participation rate of women in PAS mandated by the Food and Drug Administration (FDA) and if participation varied by clinical area. The study also evaluated the frequency in which enrollment by sex is reported by applicant reports and FDA reviews, as well as the frequency in which final study reports analyze whether outcomes differ by sex. Results: Of 89 studies with enrollment completed, data on sex of participants were available in 93% of submitted reports, while data on enrollment by sex was evaluated and noted in 43% of FDA review memos. Study participation varied by clinical area, with female participation ranging from 32% in cardiovascular PAS to 90% in PAS for reconstructive devices. Of 53 completed studies, data on enrollment by sex was provi...
Equilibrium Coalition Structures in Markets for Network Goods

Firms that produce network goods have strong incentives to adhere to common technical standards. However, adhering to common standards decreases the horizontal differentiation between goods, and that increases market competition. This paper analyzes how these countervailing forces shape firms’ decisions to comply to common technical standards under oligopoly. In the model, firms’ outputs are identical in non-network characteristics, but firms can adhere to different compatibility standards. Consequently, a good’s relative quality level is determined by the total sales of compatible goods. The technical standards coalition structures that form at equilibrium under this framework exhibit interesting characteristics. In particular, coalitions that vary greatly in total sales, profits, and prices often emerge, even though underlying products and cost structures are identical across firms.
High‐resolution microendoscope imaging of inverted papilloma and normal sinonasal mucosa: evaluation of interobserver concordance

Background High-resolution microendoscopy (HRME) enables real-time imaging of epithelial tissue. The utility of this novel imaging modality for inverted papilloma has not been previously described. This study examines the ability of otolaryngologists to differentiate between images of inverted papilloma and normal sinonasal mucosa obtained with a HRME. Methods Inverted papilloma and normal sinonasal mucosa specimens were stained with a contrast agent, proflavine. HRME images were subsequently captured. Histopathological diagnosis was obtained for each sample. Quality-controlled images were used to assemble a training set. After reviewing the training images, 6 otolaryngologists without prior HRME experience reviewed and classified test images. Results Five samples of inverted papilloma and 2 normal sinonasal mucosa samples were collected. Four representative images from each specimen were used for the 28-image test set. The mean accuracy among all reviewers was 89.9% (95% confidence interval [CI], 84.3% to 94.0%). The sensitivity to correctly identify inverted papilloma was 86.7% (95% CI, 79.2% to 92.2%), and the specificity was 92.9% (95% CI, 89.0% to 100.0%). The Fleiss kappa interrater reliability score was 0.80 (95% CI, 0.70 to 0.89). Conclusion Inverted papilloma and normal sinonasal mucosa have distinct HRME imaging characteristics. Otolaryngologists can be successfully trained to distinguish between inverted papilloma and normal sinonasal mucosa. HRME is a feasible tool for identification of inverted papilloma. By conducting future in vivo trials, HRME potentially may enable real-time surgical margin determination during surgical excision of inverted papilloma.
Dynamical Systems and Non-Hermitian Iterative Eigensolvers

Simple preconditioned iterations can provide an efficient alternative to more elaborate eigenvalue algorithms. We observe that these simple methods can be viewed as forward Euler discretizations of well-known autonomous differential equations that enjoy appealing geometric properties. This connection facilitates novel results describing convergence of a class of preconditioned eigensolvers to the leftmost eigenvalue, provides insight into the role of orthogonality and biorthogonality, and suggests the development of new methods and analyses based on more sophisticated discretizations. These results also highlight the effect of preconditioning on the convergence and stability of the continuous-time system and its discretization.
Finding the Needle in the Image Stack: Performance Metrics for Big Data Image Analysis

Explosive growth of images and video captured and recorded on computing devices has occurred in the last decade. With the emergence and widespread adoption of broadband Internet in the late 1990s and continuing to mobile and cellular phones, video and images are ubiquitous in all aspects of modern society. The challenge is how this visual data can be used and analyzed on a large scale and how the results of this analysis can be applied to society and its citizens.
Design and Fabrication of a Constant Shear Microfluidic Network for Tissue Engineering

Recent progress in microfabrication of biodegradable materials has resulted in the development of a three-dimensional construct suitable for use as a scaffold for engineering blood vessel networks. These networks are designed to replicate the critical fluid dynamic properties of physiological systems such as the microcirculation within a vital organ. Ultimately, these 3D microvascular constructs will serve as a framework for population with organ-specific cells for applications in organ assist and organ replacement. This approach for tissue engineering utilizes highly engineered designs and microfabrication technology to assemble cells in three-dimensional constructs which have physiological values for properties such as mechanical strength, oxygen, nutrient and waste transport, and fluidic parameters such as flow volume and pressure. Three-dimensional networks with appropriate values for blood flow velocity, pressure drop and hematocrit distribution have been designed and fabricated using replica molding techniques, and populated with endothelial cells for long-term microfluidic cell culture. One critical aspect of the fluid dynamics of these systems is the shear stress exerted by blood flow at the walls of the vessel; a key parameter because of well-known mechanotransduction phenomena from mechanical shear forces which govern endothelial cell behavior. In this work, we report the design and construction of three-dimensional microfluidic constructs for tissue engineering which have uniform wall shear stress throughout the network. This type of control over the shear stress offers several advantages over earlier approaches, including more uniform seeding, more rapid achievement of confluent coatings, and better control over endothelial cell behavior for in vitro and in vivo studies.
Clinical impact of endoscopic ultrasound-guided fine needle aspiration of celiac axis lymph nodes (M1a disease) in esophageal cancer

Abstract Background . The purpose of this study was to determine how endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) with a histology confirmed biopsy protocol impacted on staging and managing esophageal carcinoma in terms of resectability and neoadjuvant therapy (chemotherapy and radiation therapy). Methods . The records of 40 consecutive patients diagnosed with esophageal cancer referred for EUS staging were reviewed. Computed tomography (CT) scan then EUS imaging and EUS-guided FNA staging, including involvement of celiac node (M1a stage), surgical pathology, and subsequent treatment were correlated. Through-the-scope balloons were used for dilatation when needed to examine the celiac nodes. Results . All 40 patients followed the protocol and were successfully imaged by EUS. Sixteen of the 40 required esophageal dilatation using the through-the-scope balloon. No complications were observed from esophageal dilatation for EUS. Twenty-three (58%) met the criteria for EUS-guided FNA biopsy from a total of 40 EUS imaging procedures. Twenty (87%) of the 23 EUS-guided FNA were directed toward the celiac nodes; 18 (90%) of the 20 were positive for malignancy and were treated by chemoradiation therapy and 2 (10%) FNA were negative for malignancy and were treated by surgical resection. The CT scan was able to detect only 6 (30%) of 20 cases of suspicious celiac lymph nodes, of which 5 (83%) were positive for malignancy by FNA. Conclusions . EUS-guided FNA of celiac nodes (20 patients) directed management in all patients biopsied. EUS-guided FNA is superior to CT scan for diagnosing M1a disease. Protocol-directed EUS-guided FNA is a pivotal study when used in conjunction with stage-oriented treatment protocols for esophageal carcinoma.
Cell Surface Epidermal Growth Factor Receptors Increase Src and c-Cbl Activity and Receptor Ubiquitylation

There is an established role for the endocytic pathway in regulation of epidermal growth factor receptor (EGFR) signaling to downstream effectors. However, because ligand-mediated EGFR endocytosis utilizes multiple "moving parts," dissecting the spatial versus temporal contributions has been challenging. Blocking all endocytic trafficking can have unintended effects on other receptors as well as give rise to compensatory mechanisms, both of which impact interpretation of EGFR signaling. To overcome these limitations, we used epidermal growth factor (EGF) conjugated to polystyrene beads (EGF beads). EGF beads simultaneously activate the EGFR while blocking its endocytosis and allow analysis of EGFR signaling from the plasma membrane. Human telomerase immortalized corneal epithelial (hTCEpi) cells were used to model normal epithelial cell biology. In hTCEpi cells, both cell surface and intracellular EGFRs exhibited dose-dependent increases in effector activity after 15 min of ligand stimulation, but only the serine phosphorylation of signal transducer and activator of transcription 3 (STAT3) was statistically significant when accounting for receptor phosphorylation. However, over time with physiological levels of receptor phosphorylation, cell surface receptors produced either enhanced or sustained mitogen-activated protein kinase kinase (MEK), Casitas B-lineage lymphoma (c-Cbl), and the pro-oncogene Src activity. These increases in effector communication by cell surface receptors resulted in an increase in EGFR ubiquitylation with sustained ligand incubation. Together, these data indicate that spatial regulation of EGFR signaling may be an important regulatory mechanism in receptor down-regulation.
Tuberculosis — metabolism and respiration in the absence of growth

Human tuberculosis is a complex disease caused by bacterial populations that are located in discrete lesions (microenvironments) in a single host. Some of these microenvironments are conducive to replication, whereas others restrict bacterial growth without necessarily sterilizing the infecting microorganisms. The physical and biochemical milieu in these lesions is poorly defined. None of the existing animal models for tuberculosis (except perhaps non-human primates) reproduce the diversity of disease progression that is seen in humans. Nonetheless, transcriptomics and studies using bacterial mutants have led to testable hypotheses about metabolic functions that are essential for viability in the absence of replication. A complete picture of bacterial metabolism must balance reducing equivalents while maintaining an energized membrane and basic cellular processes.
Fixed-depth and variable-depth landmine detection using sequential probability ratio test

In this paper we use a sequential probability ratio test (SPRT) on ground penetrating radar (GPR) data to detect buried antipersonnel land mines and to reject clutter objects. Detection is performed for both fixed-depth and variable-depth cases. We use high-dimensional analysis of variance (HANOVA) to window the GPR data before SPRT analysis. Our algorithm uses a library of mine and clutter objects and performs a series of SPRTs using the object library for each unknown image. We also evaluate the performance of our fixed-depth and variable-depth detection algorithms versus noise and SPRT threshold value.
The Team-Taught Cross-Functional Core: Insights From a Long-Term Undergraduate Program

A small number of undergraduate business schools have made significant changes to their curriculum to deliver a team-taught, cross-functional undergraduate core. The author examines an exemplary early-adopting program to better understand the long-term impact such a change has had on the overall organization, and to seek insights on implementation and sustainability from these experienced faculty and administrators. The author found a program that benefits students with a well-rounded view of how business operates and the people skills employers want. In the process the study school has made broad and lasting connections to business, created a sustaining model to help support the program, and redefined its culture as a community of learners.