cssi/SciSciGPT-SciSciNet huggingface dataset:
Necessary and sufficient conditions for non-overshooting step responses for LTI systems

In this paper we consider a class of systems for which a necessary and sufficient condition is given for the determination of whether or not its impulse response starting from zero initial conditions is nonnegative. The class of plants considered is SISO, LTI, stable and strictly proper. We show that the system step response is nonovershooting by converting it to a root finding problem of a polynomial. The derived necessary and sufficient condition can then be used to develop other sufficiency conditions for more general plants where the poles need not satisfy the special form given above. Further we derive a necessary and sufficient condition guaranteeing a nonovershooting step response for another class of SISO, LTI stable and strictly proper systems. The poles of this class of systems are assumed real and of the form /spl lambda//sub i/ = i/spl lambda/, /spl lambda/ < 0, i = 1, 2,..., n. The conditions should be useful in practical control system design where a nonovershooting step response is desirable. In addition necessary and sufficient conditions are derived for a SISO plant with a complex conjugate pole pair. The latter result is then used to state conditions for a third order plant with no zeros.
Effects of Context on Students’ Molecular‐Level Ideas

In the studies reported here, we investigate the effects of context on students’ molecular‐level ideas regarding aqueous solutions. During one‐on‐one interviews, 19 general chemistry students recruited from a two‐year community college and a research university in the United States were asked to describe their molecular‐level ideas about various aqueous solutions in the contexts of conductivity and boiling‐point (BP) elevation. Results indicate that context is important for determining the molecular‐level ideas that students express. Specifically, students were significantly more likely to draw pictures of aqueous NaCl as separated ions in the conductivity context compared with the BP elevation context, for which they more often drew “molecular” NaCl. This phenomenon was particularly striking because the students drew molecular‐level NaCl(aq) pictures in the BP elevation context just minutes after completing the identical task in the context of conductivity. Additional data from laboratory assignments and...
Tuning passive, semi-active, and fully active suspension systems

A quarter car model is used to investigate the tuning of the damping for passive, on/off semiactive, continuously variable semiactive, and fully active suspensions. For the semiactive and fully active suspensions, the control algorithms are limited to feedback schemes based on absolute and relative velocity measurements. Ride comfort, road holding, and suspension travel are investigated with random input velocity to simulate road roughness. The application of a disturbance force to the sprung mass is used to investigate body control. >
Stabilization of nucleic acid triplexes by high concentrations of sodium and ammonium salts follows the Hofmeister series

The thermal stability of the triplexes d(C(+)-T)(6):d(A-G)(6);d(C-T)(6) and d(T)(21):d(A)(21);d(T)(21) was studied in the presence of high concentrations of the anions Cl(-), HPO(4)(2-), CH(3)COO(-), SO(4)(2-) and ClO(4)(-). Thermally-induced triplex and duplex transitions were identified by UV- and CD-spectroscopy and T(m) values were determined from melting profiles. A thermodynamic analysis of triplex transitions shows the limitations of commonly used treatments for determining the associated release or uptake of salt, solute or water. Enhancement of the stability of these triplexes follows the rank order of the Hofmeister series for anions of sodium and ammonium salts, whereas water structure-breaking solutes have the opposite effect. The rank order for the Hofmeister series ClO(4)(-)<I(-)<Br(-)<Cl(-)<HPO(4)(2-)<SO(4)(2-)is shown to follow their effective surface charge densities.
Hands-On--In Many Different Ways.

About a month ago, we had a major snowstorm (or at least major by New York standards), and we ended up with 15 inches of snow. Fortunately it was powdery and easy to shovel, because we don't own a snow blowerthough I did dream of such a device as we were working our way down the driveway. A couple of days later, my husband read in the paper that in the aftermath of the storm, a nearby hospital had reattached fingers to the hands of five individuals who had tried to unclog their snow blowers. All of a sudden those shovels looked great. They may be hard on our backs, but at least we came inside to warm our hands with the same number of fingers we went out with. That newspaper item made me appreciate my hands yet again, and it reminded me of a book I'd read years ago by the primate biologist, John Napier (1980). It's called simply Hands, and it covers everything from the evolution of the thumb to the classification of fingerprints. Napier was such an expert on the subject that he was asked to analyze the hand bones of Homo habilis when the Leakeys discovered these fossils in the 1950s. Napier also was a serious student of living primates, but perhaps more importantly for readers of his book, he truly loved hands. At the beginning of the book Napier notes that he didn't learn much about
Hydrology and Erosion of Loessial Watersheds

Five agricultural watersheds in the Missouri Valley deep loess soils region in western Iowa were instrumented to determine their hydrology, gully erosion, and surface erosion. Two watersheds (75 and 83 acres) were singly cropped in contoured corn, another (150 acres) in level-terraced corn, and a fourth (107 acres) in pastured grass. A fifth watershed (389 acres) was level-terraced with varied cropping. Average annual stream flow (1964-1969) from the level-terraced corn watershed was almost identical with the 7.5 in from the contoured corn watersheds; but 86% was base flow, compared with only 32% from the contoured areas. Total stream flow from the grass watershed was 60% of that from the corn watersheds. Peak rates from the grassed and level-terraced watersheds have been less than 10% of those from the contoured watersheds which ranged up to 5.84 in. per hr. Measured suspended sediment, derived from both gully and surface erosion, was 38 tons per acre per yr. and 30 tons per yr. from the two contoured-corn watersheds; but the grassed and level-terraced corn watersheds had only 0.8 tons per acre per yr. and 0.9 tons per acre per yr., respectively.
Plasma angiopoietin-2 outperforms other markers of endothelial injury in prognosticating pediatric ARDS mortality

Angiopoietin-2 (Ang-2) is a key mediator of pulmonary vascular permeability. This study tested the association between plasma Ang-2 and mortality in pediatric acute respiratory distress syndrome (A...
Effect of Host Fruit Species, Size, and Color on Parasitization of Anastrepha ludens (Diptera: Tephritidae) by Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

The effect of fruit species on parasitization of Anastrepha ludens (Loew) by Diachasmimorpha longicaudata (Ashmead) was studied. The roles of fermenting fruit volatiles, size, and color in host habitat selection by this parasitoid also were investigated. The lowest percentage parasitism was recorded for larvae in grapefruit, Citrus paradisi Macf. On the other hand, grapefruit volatiles and size proved most attractive to D. longicaudata . Greater percentage parasitism was recorded for larvae in smaller and apparently less attractive fruit. The length of the parasitoid's ovipositor, depth of the fruit pulp, and host larval behavior could explain these contrasting results. Citrus volatiles attracted almost twice as many female parasitoids as volatiles of mango, Mangifera indica L., or peach, Prunus persica L. Fruit >5 cm in diameter were equally attractive to D. longicaudata . Selection of colors by D. longicaudata was not statistically different among colors tested.
New Product Decisions by Marketing Executives: A Computer-controlled Experiment

How do marketers process information to make new product decisions? The computer-controlled experiment described in this article was designed to explore this question. Differences in information pr...
Marketing Strategy Differences between State and Privately Owned Corporations: An Exploratory Analysis:

Analysis of state and privately owned enterprises in industrialized market economies leads to the identification of differences in objectives and strategy between the two enterprise types. A series...
Substituent-induced switch of the role of charge-transfer complexes in the Diels-Alder reactions of o-chloranil and styrenes.

Addition of p-substituted styrenes, XSty (X = H, Me, MeO, or Cl) to the solutions of o-chloranil, oCA, in dichloromethane resulted in the transient formation of the charge-transfer complexes, [XSty, oCA], followed by the Diels–Alder reaction. At low temperatures, these reactions led to formation of essentially pure endocycloadducts. As expected for the inverse-electron-demand Diels–Alder reaction, the rate constants of the cycloaddition rose with the increase of the donor strength. However, while facile cycloaddition took place in the neat mixtures of the o-chloranil with p-methyl, p-chloro-, or unsubstituted styrenes at low temperatures, a similar system involving the strongest MeOSty donor was surprisingly persistent. X-ray structural measurements and quantum-mechanical computations indicated that this anomaly is related to the fact that the diene/dienophile orientation in the charge-transfer [MeOSty, oCA] complex is opposite to that in the endocycloadduct and in the lowest-energy transition state leadi...
Middle School Mathematics Teachers’ Perceptions of the Common Core State Standards for Mathematics and Related Assessment and Teacher Evaluation Systems:

In this study, U.S. middle school teachers’ perceptions of Common Core State Standards for Mathematics (CCSSM), CCSSM-related assessments, teacher evaluation processes, and resources for implementi...
Defining and Enabling Resiliency of Electric Distribution Systems With Multiple Microgrids

This paper presents a method for quantifying and enabling the resiliency of a power distribution system using analytical hierarchical process and percolation theory. Using this metric, quantitative analysis can be done to analyze the impact of possible control decisions to pro-actively enable the resilient operation of distribution system with multiple microgrids and other resources. Developed resiliency metric can also be used in short term distribution system planning. The benefits of being able to quantify resiliency can help distribution system planning engineers and operators to justify control actions, compare different reconfiguration algorithms, and develop proactive control actions to avert power system outage due to impending catastrophic weather situations or other adverse events. Validation of the proposed method is done using modified CERTS microgrids and a modified industrial distribution system. Simulation results show topological and composite metric considering power system characteristics to quantify the resiliency of a distribution system with the proposed methodology, and improvements in resiliency using two-stage reconfiguration algorithm and multiple microgrids.
The Necessity of Using Heparin in the UltraTag RBC Kit When Tagging Blood for a Nuclear Medicine Study.

The purpose of this research was to evaluate the need to use heparin when preparing an UltraTag red blood cell (RBC) kit for a nuclear medicine study. Methods: Nonheparinized blood samples (n = 15) and heparinized blood samples (n = 15) were added to UltraTag RBC kits. The samples were examined for macroscopic blood clotting and microscopic platelet clumping. As a control, samples with heparin (n = 15) and without heparin (n = 15) were used to help evaluate the effectiveness of the anticoagulant properties within the UltraTag RBC kit (sodium citrate) and whether those properties played a role in preventing clots or clumps. To detect clotting, the wooden applicator stick method was used. To detect clumping, blood smears were evaluated using a light microscope. The two samples were compared for presence of clots and clumps. Fisher exact testing was used to evaluate the significance of the data. Results: For the UltraTag RBC group, 2 of the 15 nonheparinized samples clotted and none of the 15 heparinized samples clotted; for the control group, 2 of the 15 nonheparinized samples clotted and none of the 15 heparinized samples clotted. For the Ultra-Tag RBC group, 3 of the 15 nonheparinized samples clumped and 3 of the 15 heparinized samples clumped; for the control group, 15 of the 15 nonheparinized samples clumped and 10 of the 15 heparinized samples clumped. Conclusion: When heparin is not used, the Ultra-Tag RBC kit is more likely to form clots. Heparin should always be used when preparing an Ultra-Tag RBC kit for a nuclear medicine study.
Solar radiation forecasting using zenith angle

This paper discusses simple methods for forecasting solar irradiation. We use the zenith angle (the angle between sun beam and perpendicular line on horizontal surface) to remove both seasonal and time of day effects. Then we forecast by using least-squares (LS), time-varying least squares (TVLS), exponentially weighted recursive least squares (EWRLS) and one step estimation of second order statistics. For comparison we also consider a standard method of normalizing data by subtracting mean and dividing by deviation (at that time of day, sixty days moving average) and then applying the same signal processing algorithms. Finally, we compare simulation results for different sites and various time of prediction. Simulation results shows that using zenith angle in signal processing methods improves the performance.
Emergence of Selectivity to Looming Stimuli in a Spiking Network Model of the Optic Tectum

The neural circuits in the optic tectum of Xenopus tadpoles are selectively responsive to looming visual stimuli that resemble objects approaching the animal at a collision trajectory. This selectivity is required for adaptive collision avoidance behavior in this species, but its underlying mechanisms are not known. In particular, it is still unclear how the balance between the recurrent spontaneous network activity and the newly arriving sensory flow is set in this structure, and to what degree this balance is important for collision detection. Also, despite the clear indication for the presence of strong recurrent excitation and spontaneous activity, the exact topology of recurrent feedback circuits in the tectum remains elusive. In this study we take advantage of recently published detailed cell-level data from tadpole tectum to build an informed computational model of it, and investigate whether dynamic activation in excitatory recurrent retinotopic networks may on its own underlie collision detection. We consider several possible recurrent connectivity configurations and compare their performance for collision detection under different levels of spontaneous neural activity. We show that even in the absence of inhibition, a retinotopic network of quickly inactivating spiking neurons is naturally selective for looming stimuli, but this selectivity is not robust to neuronal noise and is sensitive to the balance between direct and recurrent inputs. We also describe how homeostatic modulation of intrinsic properties of individual tectal cells can change selectivity thresholds in this network, and qualitatively verify our predictions in a behavioral experiment in freely swimming tadpoles.
In Defense of Communism Against Critical Pedagogy, Capitalism, and Trump

In this essay I challenge the anticommunism that has dominated critical pedagogy since its emergence in 1980, which coincided with imperialism’s somewhat successful counter-offensive against the global communist movement. It is within the context of the absence of communism and the communist movement that paved the way for the rise of Trump and the far right more generally. The anticommunism central to progressive forms of education, from a non-capitalist perspective, represents nothing less than the crossing of class lines. After outlining the major premises this work is grounded in, situated within a common debate between Marxism and Native studies, I review key responses to anticommunist propaganda. I then provide a brief history of the Soviet Union offering concrete responses to the anticommunism that has infected those of us on the educational left, especially in North America. I then offer a short discussion of the Black Panther Party as another example of the current relevance of the communist legacy in the United States and how this legacy has been systematically under attack. The text concludes with a brief summary of some of the core principles of the Party for Socialism and Liberation (PSL) as an example of a contemporary U.S.-based Marxist-Leninist communist party endowed with the necessary analysis and organizational structure to challenge capitalism and imperialism under a Trump presidency.
Sex- and Race-Related Differences in Characteristics and Outcomes of Hospitalizations for Heart Failure With Preserved Ejection Fraction.

BackgroundSex and race have emerged as important contributors to the phenotypic heterogeneity of heart failure with preserved ejection fraction (HFpEF). However, there remains a need to identify im...
Is It Possible to Develop a “Universal” Influenza Virus Vaccine? Potential for a Universal Influenza Vaccine

Development of optimal vaccines for influenza is challenging, in part as a result of the high antigenic variability in field strains associated with genetic shift from reassortment and genetic drift from point mutations. Discovery of conserved antigenic sites on the hemagglutinin (HA) protein for neutralizing antibodies suggested the possibility that influenza vaccines could be developed that induce focused antibody responses to the conserved neutralizing determinants, especially the HA stem region. Recent studies have focused on the antigenicity and immunogenicity of such domains, using monoclonal antibodies and candidate-engineered HA stem-based vaccines. Much progress has been made, but we still do not fully understand the biology of the immune response to this unique antigenic region.
Comparison of 30-Day Morbidity and Mortality After Arthroscopic Bankart, Open Bankart, and Latarjet-Bristow Procedures: A Review of 2864 Cases.

Background:Surgical intervention for anterior shoulder instability is commonly performed and is highly successful in reducing instances of recurrent instability.Purpose:To determine and compare the...
Murine red blood cells from genetically distinct donors cross-regulate when stored together.

BACKGROUND Donor variability of red blood cell (RBC) storage has been observed in both humans and animal models. We utilized a strain of mice with RBCs known to store well (B6) and a strain known to store poorly (FVB) to test the hypothesis that RBCs affected the storage of other RBCs. STUDY DESIGN AND METHODS Five strains of mice were used: 1) transgenic B6 mice expressing green fluorescent protein (GFP) in their RBCs (GFP.B6), 2) wild-type B6 mice, 3) wild-type FVB mice, 4) F1 crosses between GFP.B6 and FVB mice (GFP.F1), and 5) the analogous wild-type (B6xFVB) F1 cross. GFP.B6 or GFP.F1 RBCs were mixed with wild-type (non-GFP) RBCs from B6 or FVB strains before storage. Twenty-four-hour RBC recoveries were determined for stored RBCs by enumerating circulating GFP+ RBCs by flow cytometry. RESULTS Twenty-four-hour recoveries of GFP.F1 RBCs was increased by co-storage with B6 RBCs but decreased by co-storage with FVB RBCs. This effect was dose dependent when tested with GFP.B6 RBCs; the more FVB blood added, the worse the 24-hour recoveries became. RBC cross-regulation did not occur when B6 and FVB RBCs were separated by a semipermeable membrane with a 0.4-µm size cutoff. CONCLUSION These findings demonstrate that RBCs affect the storage of other RBCs, in both positive and negative directions, indicating not only that RBC storage is intrinsic to the RBC but that RBC-RBC communication occurs. Additional studies will be required to determine the nature of this effect and if these findings translate into human RBC storage.
A combined experimental and individual-differences investigation into mind wandering during a video lecture

A combined experimental-correlational study with a diverse sample (N = 182) from 2 research sites tested a set of 5 a priori hypotheses about mind wandering and learning, using a realistic video lecture on introductory statistics. Specifically, the study examined whether students' vulnerability to mind wandering during the lecture would predict learning from, and situational interest in, the video and also whether longhand note-taking would help reduce mind wandering, at least for some students. One half of the participants took notes during the video, and all were subsequently tested on lecture content without notes. Regression and mediation analyses indicated that (a) several individual-differences variables (e.g., pretest score, prior math interest, classroom media multitasking habits) uniquely predicted in-lecture mind wandering frequency; (b) although the note-taking manipulation did not reduce mind wandering at the group level, note-taking still reduced mind wandering for some individuals (i.e., those with lower prior knowledge and those who took notes of high quality and quantity); (c) mind wandering uniquely predicted both learning (posttest) and situational interest outcomes above and beyond all other individual-differences variables; (d) moreover, mind wandering significantly mediated the effects of several individual differences; and, finally, (e) not all types of mind wandering were problematic-in fact, off-task reflections about lecture-related topics positively predicted learning. These results, which were generally robust across the 2 sites, suggest that educationally focused cognitive research may benefit from considering attentional processes during learning as well as cognitive and noncognitive individual differences that affect attention and learning. (PsycINFO Database Record
Ceradenia spectabilis (Polypodiaceae), a New Species from Cerro del Torrá, Colombia

Abstract Ceradenia spectabilis, a new species, is described from Cerro del Torra, an isolated peak in western Colombia well known for harboring rare and narrowly distributed species of plants. The new species is readily distinguished from its congeners by its broadly alate petiole and rachis, creeping rhizome with widely spaced leaves, and large oblanceolate leaves with elongate and ascending pinnae. Three other species, C. curvata, C. discolor, and C. pearcei, share characteristics in common with C. spectabilis including thick sub-spongiose laminae that are sparsely setose (or setae absent), provided throughout with whitish waxy glands, alate petioles and rachises, setose rhizome scales that are also provided with a few whitish waxy glands, and sub-marginal sori. However, Ceradenia spectabilis can be distinguished from each of them by its longer petioles (4–6 cm long vs. 2 cm or less), broader petiole wings (2.5–3.5 mm wide vs. 0.5 cm or less), and longer pinnae (up to 10 cm long vs. 4 cm long or less). ...
Bioaugmentation of sidestream nitrifying-denitrifying phosphorus-accumulating granules in a low-SRT activated sludge system at low temperature

Sidestream granular activated sludge grown on anaerobic digester dewatering centrate was bioaugmented and selectively retained to enable high nitrification performance of a 2.5-day aerobic SRT non-nitrifying flocculent activated sludge system at 12 °C. Sidestream-grown granules performed enhanced biological phosphorus removal (EBPR) and short-cut nitrogen removal via nitrite. After bioaugmentation, EBPR continued in the mainstream but ammonia oxidation was eventually to nitrate. Low effluent NH3-N concentrations from 0.6 to 1.7 mg/L were achieved with nitrification solely by granules, thus enabling denitrification and nitrogen removal. Molecular microbial analyses of flocs and granules also suggested that nitrifying organisms persisted on granules with minimal nitrifier loss to flocs. Mainstream granule mass at the end of bioaugmentation testing was 1.7 times the amount of sidestream granules added, indicating mainstream granular growth. Nitrite and nitrate availability during the unaerated feeding period encouraged significant growth of ordinary heterotrophs in mainstream granules, but nevertheless mainstream nitrification capacity was sustained.
Intersections of Culture, Language, and Mathematics Education: Looking Back and Looking Ahead

This paper draws from a research agenda focused on the interplay of culture, language and mathematics teaching and learning, particularly in working-class Mexican-American communities in the United States. Drawing on data collected over several years, I emphasize the need for a coordinated effort to the mathematics education of non-dominant students, an effort that involves teachers and other school personnel, the students’ families, and the students themselves. Through the voices of parents, teachers, and students, I illustrate the resources that non-dominant students bring to school but often go untapped, and the tensions that this may carry. Following a socio-cultural approach grounded on the concept of funds of knowledge, I argue for the need to develop stronger communication among the interested parties to develop learning experiences in mathematics that build on the knowledge, the language and cultural resources, and the forms of participation in the students’ communities.
Failure mechanisms in pre-cracked Ni-graphene nanocomposites

Abstract Graphene is a 2-D material with superior mechanical properties and is highly desirable as a filler in nanocomposite materials. However, the mechanical properties of the resulting nanocomposite are anisotropic, with strengthening or weakening depending on the loading direction. The presence of graphene also introduces new failure mechanisms to the matrix it is embedded within. In addition, the structure of graphene, pristine or polycrystalline, can affect its interfacial properties in the nanocomposite. We use molecular dynamics to predict the failure mechanisms of Ni-graphene nanocomposites for different loading directions with a crack present in the Ni matrix. We observe a variety of failure mechanisms including dislocation nucleation, graphene bond breaking, and delamination. We also compare the yield stress and strain of nanocomposites with either pristine or polycrystalline graphene. We find that graphene of either kind can improve the yield stress of Ni by 27–76% when loaded parallel to the graphene sheet. We also find that, compared to pristine graphene, polycrystalline graphene can improve the yield stress of a Ni-graphene nanocomposite by up to 27%. This is explained by the higher interfacial shear stress of polycrystalline graphene on Ni’s (1 1 1) surface compared to pristine graphene. This is in part related to the wrinkling of graphene sheets, which differs between polycrystalline and pristine sheets. Our research indicates that metal-graphene nanocomposites benefit from graphene’s polycrystalline structure when superior mechanical properties are desired.
Nonisothermal Stability Assessment of Stable Pharmaceuticals: Testing of a Clindamycin Phosphate Formulation

The stability of an antibiotic formulation (clindamycin phosphate in dextrose), which is stable at room temperature, was assessed by nonisothermal kinetic analysis at elevated temperatures. A preliminary study, conducted to establish apparent rate order, verified the appropriateness of a first-order kinetic model. The test formulation was then heated linearly from 70 to 90°C over 12 hr. Data (drug concentration, temperature, and time) were fitted to the first-order model using nonlinear least-squares regression. Arrhenius parameter estimates obtained from three nonisothermal trials, and rate constants at 25°C derived by extrapolation, demonstrated acceptable reproducibility and were in agreement with values derived from isothermal experiments at 30, 45, 55, 65, and 75°C. First-order rate constants obtained from studies conducted for 20 months at 25°C were in accord with isothermal and nonisothermal results.
Fatigue Crack Growth

Metal fatigue is a major cause for failure of mechanical and structural components. We review the fracture mechanics of fatigue and Paris-Erdogan law for the mean behavior. After a consideration of experimental data reported by Virkler et al. (1979), we propose a continuous semimarkov process to model crack growth. The model accounts for the material randomness and sees crack as a motion in a random field.
The Transition from Direct Caregiver to Administrator in Early Childhood Education

This paper recommends ways to improve the preparation of child care administrators. The discussion is based on a research study that explored the nature of this complex administrative role and how it was learned. Sixteen preschool directors, mostly women with little formal preparation in educational leadership, moved into the position from being teachers. They described struggles with issues of isolation without a peer group and resolving a perceived tension with being an authority figure while needing to provide responsive support to other adults in a nurturing environment (both teachers and parents). The most difficult hurdles to becoming a leader in early childhood settings were internal rather than organizational management concerns. Successful strategies for addressing these issues included having an assistant director or mentor inside the organization who could act as a sounding-board and maintaining external relationships with peers in other educational settings who could offer alternative perspectives on shared problems. The directors were not advocates of formal programs in educational administration in spite of the difficulties of learning by experience. However, the best preparation for early childhood administrators would encompass both practical and theoretical knowledge and include some form of internship.
TROPICAL METEOROLOGY & Climate | Hadley Circulation

The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Nino and La Nina events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.
Cost‐Benefit Analysis: An Organizational Design Perspective

This article analyzes cost-benefit analysis (CBA) from an organizational design perspective, a viewpoint not previously offered in debates about CBA. This perspective, widely used in the business literature, reveals business firms do not use CBA for anything but routine, non-complex decisions because they operate in uncertain environments. Likewise, regulators operate under conditions of bounded rationality, forcing them to eschew CBA and adopt the same type of heuristical decision-making used in private organizations. Despite this, a recent book by Dean Revesz and Professor Livermore favors the use of CBA. Like other CBA supporters, they insist on comprehensive rationality and ignore what Nobel laureate Herbert Simon has taught us. With bounded rationality, decision-making that serves the ends of an organization is "rational," even if it is not based on CBA.
Understanding what teachers gain from professional development at historic sites

Despite decades of formal work with teachers, little is known about what they gain from professional development at and with historic sites. This article presents the first data-set from a 3-year Institute for Museum and Library Services National Leadership Grant project designed to develop a broad-based assessment for understanding what teachers learn in historic site-based professional development. The centerpiece of this project is an assessment tool based in Q methodology. This round of study focuses on the pre-post Q sorts and interviews of 29 teachers in a history-focused institute regarding how they see their work at historic sites affecting their professional development. Contrary to advocates’ assertions, results indicate that only a small number of participants specifically set out to seek historical disciplinary expertise and analysis, while greater emphasis was placed on working with content-area peers, developing pedagogical practices, and the power of place.
Ultra-Wide Band On-Chip Circulators for Full-Duplex Communications

The thrust toward 5G communication has placed an increasing weight upon the performance bounds of current technologies. As the number of spectrum users continues to grow, the need for efficient use of spectral resources grows along with it. SSDL, which stands for Sequentially-Switched Delay Lines, provides a solution to this issue. The SSDL concept is a time-switching strategy, which uses a set of switches and transmission lines to simultaneously route transmitted and received waveforms to their respective ports over a broad bandwidth. SSDL does not incur a lower bound to its operating frequency, and experimental results of two different SSDL architectures demonstrate broadband non-reciprocity.
Analysis of Dynamic Response of an MRI-Guided Magnetically-Actuated Steerable Catheter System

This paper presents a free-space open-loop dynamic response analysis for an MRI -guided magnetically-actuated steerable intra-vascular catheter system. The catheter tip is embedded with a set of current carrying micro-coils. The catheter is directly actuated via the magnetic torques generated on these coils by the magnetic field of the magnetic resonance imaging (MRI)scanner. The relationship between the input current commands and catheter tip deflection angle presents an inherent nonlinearity in the proposed catheter system. The system nonlinearity is analyzed by utilizing a pendulum model. The pendulum model is used to describe the system nonlinearity and to perform an approximate input-output linearization. Then, a black-box system identification approach is performed for frequency response analysis of the linearized dynamics. The optimal estimated model is reduced by observing the modes and considering the Nyquist frequency of the camera system that is used to track the catheter motion. The reduced model is experimentally validated with $3D$ open-loop Cartesian free-space trajectories. This study paves the way for effective and accurate free-space closed-loop control of the robotic catheter with real-time feedback from MRI guidance in subsequent research.
Biological pathways for historical trauma to affect health: A conceptual model focusing on epigenetic modifications

Despite their unique histories, environments, and lifestyles, historically subjugated populations consistently show poorer health outcomes compared to the general population. The theory of historical trauma, which argues that a collective trauma experienced by one generation can negatively impact the wellbeing of future generations, is a potential framework to understand the adverse health outcomes seen among populations with histories of subjugation. However, the biological pathways through which historical trauma actually impacts health have been unclear. In this paper, we present a cumulative, two pathway model that describes how historical trauma can impact health in contemporary generations. The first pathway suggests that personal exposure to trauma or stressors, which are more common among populations that have experienced historical trauma, can induce epigenetic modifications that can contribute to the development of poor health. The second pathway posits that poor health can occur through intergenerational epigenetic modifications in response to parental and grandparental trauma or stressor exposures. Taken together, these pathways can provide insight into the higher rates of adverse health outcomes among individuals from populations that have historically endured collective trauma. Importantly, the potential reversible nature of epigenetic modifications suggests that these trauma-induced epigenetic effects are not necessarily permanent and that improvements in environmental conditions could reduce the high prevalence of poor health among historically disadvantaged communities.
Observing Severe Drought Influences on Ozone Air Pollution in California

Drought conditions affect ozone air quality, potentially altering multiple terms in the O3 mass balance equation. Here, we present a multiyear observational analysis using data collected before, during, and after the record-breaking California drought (2011–2015) at the O3-polluted locations of Fresno and Bakersfield near the Sierra Nevada foothills. We separately assess drought influences on O3 chemical production (PO3) from O3 concentration. We show that isoprene concentrations, which are a source of O3-forming organic reactivity, were relatively insensitive to early drought conditions but decreased by more than 50% during the most severe drought years (2014–2015), with recovery a function of location. We find drought–isoprene effects are temperature-dependent, even after accounting for changes in leaf area, consistent with laboratory studies but not previously observed at landscape scales with atmospheric observations. Drought-driven decreases in organic reactivity are contemporaneous with a change in ...
Implementation of cancer next-generation sequencing testing in a community hospital

In the current era of personalized medicine, the field of oncology is witnessing a paradigm shift in patient care that is driving a tighter integration of genomic analysis modalities in patient care decision. This is driven by the expanding category of targeted therapies that require a broader understanding of the mutational profile of patient samples to more precisely guided personalized treatment decisions. Next-generation sequencing (NGS) has proved to be of tremendous power in detecting and characterizing a broad spectrum of activating or loss-of-function mutations across many gene targets. This power of NGS also results in significant challenges related to technical expertise, bioinformatics, computing infrastructure, laboratory practices, and integration into clinical decision-making. These challenges are particularly relevant to smaller and mid-tier hospital networks that are faced with the need to modernize their clinical practices and offer their patients access to advanced genomic technologies to improve outcomes. Adoption of such personalized medicine relies on information about a patient's cancer genome and the identification of its variants. This is best achieved using NGS. However, there are challenges to the adoption of such a complex technology and workflow, especially in smaller hospital systems. This commentary summarizes key considerations and challenges related to implementation of NGS in a community hospital setting.
Buying random votes is as hard as buying no-votes.

In voting systems where a mark in a fixed position may mean a vote for Alice on a ballot, and a vote for Bob on another ballot, an attacker may coerce voters to put their mark at a certain position, enforcing effectively a random vote. This attack is meaningful if the voting system allows to take receipts with them and/or posts them to a bulletin board. The coercer may also ask for a blank receipt. We analyze this kind of attack and prove that it requires the same effort as a comparable attack would require against any voting system, even one without receipts.
A cumulative gravity model for inter-urban spatial interaction at different scales

Abstract The classical gravity model assumes the knowledge of origin-destination (OD) flows between places. While this is reasonable for some modes of transportation such as air travel, it presents challenges to many other applications such as road travel where the observed flow on road segments, such as annual average daily traffic (AADT), may involve traffic for multiple OD pairs. This article introduces a methodology to calibrate a cumulative gravity model on a scale-specific road network. The model infers the traffic on OD pairs from the knowledge of link flows and we document its effectiveness in predicting the bidirectional volume of traffic on highways in the United States. Census data and state AADT were used to calibrate both the noncumulative and cumulative gravity models in three different regions in the western US: Arizona only, 10 western US states, and 16 western US states. The road networks were built by defining nodes as population centers of >10,000 inhabitants for Arizona and >500,000 for the other two networks. A systematic method to remove junction nodes that do not satisfy population threshold requirements but are necessary to maintain network connectivity is presented. The cumulative gravity model performed better (with a R-squared value of 0.93 in Arizona) than the standard model, but the improvement, based on two goodness-of-fit metrics (Common Part of Commuters and least squares) was above 2% only in the Arizona network. Removal of commercial traffic from the data further improved the model's calibration in the 10-state network. A thresholding method that connects the cumulative to the standard gravity model reveals that most road trips in Arizona are within the 150-mile range and that this distance increases to 500 miles in both western networks. Potential future applications of the present work are discussed.
Surgical outcomes in adults with purpura fulminans: A systematic review and patient-level meta-synthesis

Cutaneous manifestations of purpura fulminans (PF) present many challenges for clinicians and surgeons. In a state of septic shock complicated by limb ischemia, surgical interventions are necessary to control the pathological cascade and improve patient outcomes. The objective of this article was to report etiologies and surgical outcomes associated with cutaneous manifestations in adults. This systematic review and meta-analysis compared 190 adult patients with etiologies, signs and symptoms, and surgical outcomes associated with cutaneous manifestations of PF. The PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were systematically and independently searched. Patient and clinical characteristics, surgical interventions, outcomes, and complications were recorded. Seventy-nine studies were eligible for the systematic review, and 77 were eligible for meta-analysis using Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) and Cochrane guidelines. A total of 71/190 (38%) cases reported surgical debridement. Fasciotomies were reported in 12/190 (6%) cases and 20 procedures. Amputations were reported in 154/190 (81%) cases. Reconstruction was reported in 45 cases. Skin grafts were applied in 31 cases. Flaps were used for reconstruction in 28 cases. Median (IQR) surgical procedures per patient were 4 (4, 5) procedures. Infectious organisms causing PF were 32% Neisseria meningitidis (n = 55) and 32% Streptococcus pneumonia (n = 55). Coagulase-negative Staphylococcus (95% confidence interval (CI)(8.2–177.9), p = 0.032), Haemophilus influenza (95%CI (7.2–133), p = 0.029), Streptococcus pneumonia (95% CI (13.3–75.9), p = 0.006), and West Nile Virus (95%CI (8.2–177.9), p = 0.032) were associated with significantly more extensive amputations compared to other organisms. This systematic review and patient-level meta-analysis found the most common presentation of PF was septic shock from an infectious organism. Neisseria meningitidis and Streptococcus pneumonia were equally the most common organisms associated with PF. The majority of cases were not treated in a burn center. The most common surgeries were amputations, with below-the-knee-amputations being the most common procedure. Skin grafting was the most commonly performed reconstructive procedure. The most common complications were secondary infections. Organisms with significantly more extensive amputations were coagulase-negative Staphylococcus, Haemophilus influenza, Streptococcus pneumonia, and West Nile Virus. Interpretation of findings should be cautioned due to limited sample data.
Low-dimension materials-based interlayer tunnel field-effect transistors: technologies, current transport models, and integration

A new type of graphene-switching transistor termed as "junctionless tunnel effect transistor (JTET)" based on graphene-hBN-graphene vertical heterostructure and interlayer tunneling is proposed and an analytical current transport model has been developed. The drain current in graphene JTET flows between the source and drain of bottom graphene layer. The current in the channel is regulated by the shift in channel Fermi level which depends on the net vertical tunneling of carriers from top graphene to bottom graphene layers through hBN. Performance of graphene JTET is evaluated for different numbers of hBN layers. A comparison between graphene JTET and ITRS projected 2020 nMOSFET is also provided apart from graphene JTET performance comparison with similar iTFETs. Current saturation is observed in graphene JTET output characteristic for both p- and n -type operations, which makes graphene JTET suitable for digital circuit design. Graphene JTET is also capable of suppressing NDR effect, and shows steep subthreshold slope with high on/off current ratio and normal operation at room temperature. A complementary vertical inverter is presented similar to a CMOS inverter and analyzed for its performance. Graphene JTET vertical inverter gives inverter gain higher than unity at the low supply voltage and both low and high noise margins. It is concluded that with an average 25 mV/decade subthreshold slope at 0.1 V supply voltage and a current ratio of ~104 , graphene interlayer junctionless tunnel effect transistor meets the ITRS requirement of device scaling for energy-efficient circuit design.
Systematic Matter and Binding-Energy Distributions from a Dispersive Optical Model Analysis.

We present the first systematic nonlocal dispersive optical model analysis using both bound-state and scattering data of $^{16,18}\mathrm{O}$, $^{40,48}\mathrm{Ca}$, $^{58,64}\mathrm{Ni}$, $^{112,124}\mathrm{Sn}$, and $^{208}\mathrm{Pb}$. In all systems, roughly half the total nuclear binding energy is associated with the most-bound 10% of the total nucleon density. The extracted neutron skins reveal the interplay of asymmetry, Coulomb, and shell effects on the skin thickness. Our results indicate that simultaneous optical model fits of inelastic scattering and structural data on isotopic pairs are effective for constraining asymmetry-dependent nuclear structural quantities otherwise difficult to observe experimentally.
Food for Thought: Nourishing the Dancing Body

A number of complex, interrelated issues impact dancer norms and nourishment knowledge, which can make the subject daunting to address. This article provides a curricular model which examines aspec...