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A Concept Inventory (CI) is an assessment to measure student conceptual understanding of a particular topic. This article presents the results of a CI for basic data structures (BDSI) that has been previously shown to have strong evidence for validity. The goal of this work is to help researchers or instructors who administer the BDSI in their own courses to better understand their results. In support of this goal, we discuss our findings for each question of the CI using data gathered from 1,963 students across seven institutions.

This article discusses the use of calcium phosphate bone cement (CPC) in retrosigmoid craniotomies to reduce the rates of postoperative complications such as pseudomeningocele and cerebrospinal fluid (CSF) leak. The study includes a cohort of 287 patients who underwent retrosigmoid craniotomies, with 40 of them receiving CPC for bone flap closure. Within the CPC cohort, no pseudomeningoceles or CSF leaks occurred at the craniotomy site, compared to 18 patients in the non-CPC cohort. The systematic literature review also supports the effectiveness of CPC in reducing the risk of pseudomeningocele/CSF leak and infection. Overall, the use of CPC in retrosigmoid craniotomies is considered a safe and effective strategy to lower the incidence of complications. [Extracted from the article]

Today’s large-scale services generally exploit loosely-coupledarchitectures that restrict functionality requiring tight cooperation (e.g.,leader election, synchronization, and reconfiguration) to a small subset ofnodes. In contrast, this work presents a way to scalably deploy tightly-coupleddistributed systems that require significant coordination among a large numberof nodes in the wide area. Our design relies upon a new reliable groupmembership abstraction to ensure that either group members are capable ofcommunicating or that new groups form. In particular, we deploy a distributedrate limiting (DRL) service within a global testbed infrastructure. Unlike mostdistributed services, DRL can safely operate in separate partitionssimultaneously, but requires timely snapshots of global state within each. OurDRL implementation leverages our proposed group membership abstraction and arobust gossip-based communication protocol, conjoining the fates of viewmaintenance and data dissemination. Through local and wide-area experiments, weillustrate that DRL remains accurate and responsive in the face of a variety offailure scenarios.Pre-2018 CSE ID: CS2012-0973

Government, medical, financial, and web-based services increasinglydepend on the ability to rapidly sift through huge, evolving data sets. Thesedata-intensive applications perform complex multi-step computations oversuccessive generations of data inflows (e.g., weekly web crawls, nightlytelescope dumps, or hourly surveillance videos). Because of the data volumesinvolved, applications must avoid reprocessing old data when new data arrivesand instead process incrementally. Unlike in stream-based systems, incomingdata does not have to be processed immediately, permitting work to be amortizedvia bulk processing. Such bulk-incremental processing represents an emergingclass of applications whose needs are not fully met by current systems. Thispaper presents a generalized architecture for bulk-incremental processingsystems (BIPS), simplifying the creation of such programs. In contrast withincremental view maintenance in data warehousing, BIPS provides flexiblelow-level primitives for managing incremental data and processing, upon whichboth relational and non-relational operations can be implemented. The paperdescribes the BIPS programming model along with several example applicationsand examines some key implementation choices. These choices are shown to play amajor role in overall system performance, via experiments on a large testbedcluster.Pre-2018 CSE ID: CS2009-0951

Objective: There is widespread agreement about the key role of hemoglobin for oxygen transport. Both observational and interventional studies have examined the relationship between hemoglobin levels and maximal oxygen uptake (V˙O2max) in humans. However, there exists considerable variability in the scientific literature regarding the potential relationship between hemoglobin and V˙O2max. Thus, we aimed to provide a comprehensive analysis of the diverse literature and examine the relationship between hemoglobin levels (hemoglobin concentration and mass) and V˙O2max (absolute and relative V˙O2max) among both observational and interventional studies. Methods: A systematic search was performed on December 6th, 2021. The study procedures and reporting of findings followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Article selection and data abstraction were performed in duplicate by two independent reviewers. Primary outcomes were hemoglobin levels and V˙O2max values (absolute and relative). For observational studies, meta-regression models were performed to examine the relationship between hemoglobin levels and V˙O2max values. For interventional studies, meta-analysis models were performed to determine the change in V˙O2max values (standard paired difference) associated with interventions designed to modify hemoglobin levels or V˙O2max. Meta-regression models were then performed to determine the relationship between a change in hemoglobin levels and the change in V˙O2max values. Results: Data from 384 studies (226 observational studies and 158 interventional studies) were examined. For observational data, there was a positive association between absolute V˙O2max and hemoglobin levels (hemoglobin concentration, hemoglobin mass, and hematocrit (P<0.001 for all)). Prespecified subgroup analyses demonstrated no apparent sex-related differences among these relationships. For interventional data, there was a positive association between the change of absolute V˙O2max (standard paired difference) and the change in hemoglobin levels (hemoglobin concentration (P<0.0001) and hemoglobin mass (P = 0.006)). Conclusion: These findings suggest that V˙O2max values are closely associated with hemoglobin levels among both observational and interventional studies. Although our findings suggest a lack of sex differences in these relationships, there were limited studies incorporating females or stratifying results by biological sex. [ABSTRACT FROM AUTHOR]

Oxygen transport from the lungs to peripheral tissue is dependent on the affinity of hemoglobin for oxygen. Recent experimental data have suggested that the maximum human capacity for oxygen uptake and utilization (V̇O2max) at sea level and altitude (~3000 m) is sensitive to alterations in hemoglobin‐oxygen affinity. However, the effect of such alterations on V̇O2max at extreme altitudes remains largely unknown due to the rarity of mutations affecting hemoglobin‐oxygen affinity. This work uses a mathematical model that couples pulmonary oxygen uptake with systemic oxygen utilization under conditions of high metabolic demand to investigate the effect of hemoglobin‐oxygen affinity on V̇O2max as a function of altitude. The model includes the effects of both diffusive and convective limitations on oxygen transport. Pulmonary oxygen uptake is calculated using a spatially‐distributed model that accounts for the effects of hematocrit and hemoglobin‐oxygen affinity. Systemic oxygen utilization is calculated assuming Michaelis–Menten kinetics. The pulmonary and systemic model components are solved iteratively to compute predicted arterial and venous oxygen levels. Values of V̇O2max are predicted for several values of hemoglobin‐oxygen affinity and hemoglobin concentration based on data from humans with hemoglobin mutations. The model predicts that increased hemoglobin‐oxygen affinity leads to increased V̇O2max at altitudes above ~4500 m. [ABSTRACT FROM AUTHOR]

The article titled "Heat and carbon monoxide exposure: Is two better than one?" published in Experimental Physiology explores the potential ergogenic effects of acute interventions involving carbon monoxide exposure and heat exposure. The study conducted by DiMarco et al. investigates the circulatory erythropoietin (EPO) response and physiological parameters in 16 participants. The findings suggest that while both interventions individually increase EPO, combining them does not result in an augmented increase. Additionally, the study addresses potential sex differences, with females showing a greater EPO response compared to males. The article highlights the complexity of oxygen homeostasis and raises further questions for future research. [Extracted from the article]

Characterization of the elasticity of biological cells is growing as a new way to gain insight into cell biology. Cell mechanics are related to most aspects of cellular behavior, and applications in research and medicine are broad. Current methods are often limited since they require physical contact or lack resolution. From the methods available for the characterization of elasticity, those relying on high frequency ultrasound (phonons) are the most promising because they offer label-free, high (even super-optical) resolution and compatibility with conventional optical microscopes. In this Perspective contribution, we review the state of the art of picosecond ultrasonics for cell imaging and characterization, particularly for Brillouin scattering-based methods, offering an opinion for the challenges faced by the technology. The challenges are separated into biocompatibility, acquisition speed, resolution, and data interpretation and are discussed in detail along with new results. [ABSTRACT FROM AUTHOR]

Recently, researchers in our laboratory have shown that humans with genetic mutations resulting in high-affinity haemoglobin (HAH) demonstrate better maintained aerobic capacity and peak power output during hypoxic exercise versus normoxic exercise in comparison to humans with normal-affinity haemoglobin. However, the influence of HAH on tissue oxygenation within exercising muscle during normoxia and hypoxia is unknown. Therefore, we examined near-infrared spectroscopy-derived oxygenation profiles of the vastus lateralis during graded cycling exercise in normoxia and hypoxia among humans with HAH (n = 5) and control subjects with normal-affinity haemoglobin (n = 12). The HAH group elicited a blunted increase of deoxygenated haemoglobin+myoglobin during hypoxic exercise compared with the control group (P = 0.03), suggesting reduced fractional oxygen extraction in the HAH group. In addition, the HAH group maintained a higher level of muscle tissue oxygen saturation during normoxic exercise (HAH, 75 ± 4% vs. controls, 65 ± 3%, P = 0.049) and there were no differences between groups in muscle tissue oxygen saturation during hypoxic exercise (HAH, 68 ± 3% vs. controls, 68 ± 2%, P = 0.943). Overall, our results suggest that humans with HAH might demonstrate divergent patterns of fractional oxygen extraction during hypoxic exercise and elevated muscle tissue oxygenation during normoxic exercise compared with control subjects. [ABSTRACT FROM AUTHOR]

With two nonoverlapping beams incident at different angles on a heavily scattering medium, the spatial correlation of speckle patterns over source position has a beat that is related to the incident angle difference. A model presented explains the measurement. The spatial correlation is shown to decorrelate faster than the beam intensity correlation function and to be sensitive to the incident field profile. Increased scatter results in more rapid decorrelation. This work suggests new opportunities for imaging through scattering media. OCIS codes: 030.6600, 030.6140, 110.6150, 290.7050.

Impedance measurements in whole lenses showed that lens fiber cells possess different permeability properties to the epithelial cells from which they differentiate. To confirm these observations at the cellular level, we analyzed the membrane properties of fiber cells isolated in the presence of the nonselective cation channel inhibitor [Gd.sup.3+]. Isolated fiber cells were viable in physiological [[Ca.sup.2+]] and exhibited a range of lengths that reflected their stage of differentiation. Analysis of a large population of fiber cells revealed a subgroup of cells whose conductivity matched values measured in the whole lens (1). In this group of cells, membrane resistance, conductivity, and reversal potential all varied with cell length, suggesting that the process of differentiation is associated with a change in the membrane properties of fiber cells. Using pharmacology and ion substitution experiments, we showed that newly differentiated fiber cells (< 150 [micro] m) contained variable combinations of [Ba.sup.2+]-and tetraethylammonium-sensitive [K.sup.+] currents. Longer fiber cells (150-650 [micro] m) were dominated by a lyotropic anion conductance, which also appears to plays a role in the intact lens. Longer cells also exhibited a low-level, nonselective conductance that was eliminated by the replacement of extracellular [Na.sup.+] with N-methyl-D-glucamine, indicating that the lens contains both [Gd3.sup.+]-sensitive and -insensitive nonselective cation conductances. Fiber cell differentiation is therefore associated with a shift in membrane permeability from a dominant [K.sup.+] conductance(s) toward larger contributions from anion and nonselective cation conductances as fiber cells elongate. electrophysiology; potassium channel; anion channel; nonselective cation channel

A multigrid inversion method with variable resolution data and image spaces is proposed, whereby the algorithm changes grid resolution of both data space and image space, thus improving computational efficiency as compared to previous methods considering image space only. Applications to conventional transmission and emission tomography problems demonstrate substantially reduced computation relative to the fixed-grid iterative coordinate descent (ICD) algorithm and the multigrid inversion with fixed-data resolution.

We present a method for detecting and localizing a fluorescing tumor obscured underneath several millimeters of a multiply scattering, homogeneous medium from fluorescence measurements made above the surface. Using a statistical model of the measurement system, we develop approaches for detection by use of a binary hypothesis testing approach and localization by use of maximum-likelihood estimation. We also compute the probability of tumor detection and the Cramer-Rao lower bound for the localization estimate error, which are performance metrics that could potentially be optimized in an experimental design. We validate the methods in an experimental study involving an excised mouse tumor tagged with a new folate-indocyanine dye and obscured under a tissue-simulating lipid suspension.

A nonlinear field-effect transistor equivalent-circuit model is examined to identify the fundamental mechanisms that up-convert baseband 1/f noise to near-carrier sideband noise when the device is operated in the large-signal regime. This model captures all physical noise sources and nonlinearities in the transistor, and thereby allows a general cause-and-effect treatment. The noise sources in the equivalent-circuit model are determined using low-frequency spectrum analyzer and microwave noise-figure meter data. Using the example of an AIGaN/GaN high electron-mobility transistor, the developed model correctly describes both the measured near-carrier sideband amplitude and phase noise simultaneously. Index Terms--Amplitude noise, gallium nitride, noise measurement, nonlinearities, phase noise, semiconductor device noise.