Search

We report the rate of cosmic ray air showers with multiplicities exceeding 15 muon tracks recorded in the NOvA Far Detector between May 2016 and May 2018. The detector is located on the surface under an overburden of 3.6 meters water equivalent. We observe a seasonal dependence in the rate of multiple-muon showers, which varies in magnitude with multiplicity and zenith angle. During this period, the effective atmospheric temperature and surface pressure ranged between 210 K and 230 K and 940 mbar and 990 mbar, respectively; the shower rates are anticorrelated with the variation in the effective temperature. The variations are about 30% larger for the highest multiplicities than the lowest multiplicities and 20% larger for showers near the horizon than vertical showers.

This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 km and 810 km from the beam source, is analyzed using an exposure of $12.51\times10^{20}$ protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of $121$ of neutral-current candidates are observed at the Far Detector, compared to a prediction of $122\pm11$(stat.)$\pm15$(syst.) assuming mixing between three active flavors. No evidence for $\bar{\nu}_{\mu}\rightarrow\bar{\nu}_{s}$ oscillation is observed. Interpreting this result within a 3+1 model, constraints are placed on the mixing angles ${\theta}_{24} < 25^{\circ}$ and ${\theta}_{34} < 32^{\circ}$ at the 90% C.L. for $0.05$eV$^{2} \leq \Delta m^{2}_{41} \leq 0.5$eV$^{2}$, the range of mass splittings that produces no significant oscillations at the Near Detector. These are the first 3+1 confidence limits set using long-baseline accelerator antineutrinos., Comment: 8 pages, 4 figures

The two-detector design of the NOvA neutrino oscillation experiment, in which two functionally identical detectors are exposed to an intense neutrino beam, aids in canceling leading order effects of cross-section uncertainties. However, limited knowledge of neutrino interaction cross sections still gives rise to some of the largest systematic uncertainties in current oscillation measurements. We show contemporary models of neutrino interactions to be discrepant with data from NOvA, consistent with discrepancies seen in other experiments. Adjustments to neutrino interaction models in GENIE that improve agreement with our data are presented. We also describe systematic uncertainties on these models, including uncertainties on multi-nucleon interactions from a newly developed procedure using NOvA near detector data., Comment: Code implementing adjustments to GENIE 2.12.2 described in this paper is available at https://github.com/novaexperiment/NOvARwgt-public

The NOvA experiment has made a $4.4\sigma$-significant observation of $\bar\nu_{e}$ appearance in a 2 GeV $\bar\nu_{\mu}$ beam at a distance of 810 km. Using $12.33\times10^{20}$ protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 $\bar\nu_{\mu} \rightarrow \bar\nu_{e}$ candidates with a background of 10.3 and 102 $\bar\nu_{\mu} \rightarrow \bar\nu_{\mu}$ candidates. This new antineutrino data is combined with neutrino data to measure the oscillation parameters $|\Delta m^2_{32}| = 2.48^{+0.11}_{-0.06}\times10^{-3}$ eV$^2/c^4$, $\sin^2 \theta_{23} = 0.56^{+0.04}_{-0.03}$ in the normal neutrino mass hierarchy and upper octant and excludes most values near $\delta_{\rm CP}=\pi/2$ for the inverted mass hierarchy by more than 3$\sigma$. The data favor the normal neutrino mass hierarchy by 1.9$\sigma$ and $\theta_{23}$ values in the upper octant by 1.6$\sigma$., Comment: 8 pages, 3 figures. Supplementary material attached (6 figures). To view attachments, please download and extract the gzipped tar source file listed under "Other formats". Fixed supplementary material to include just the compiled pdf not the Latex Source

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We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810\,km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05$\times$10$^{20}$ protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with $83.5 \pm 9.7 \mbox{(stat.)} \pm 9.4 \mbox{(syst.)}$ events predicted assuming mixing only occurs between active neutrino species. No evidence for $\nu_{\mu} \rightarrow \nu_{s}$ transitions is found. Interpreting these results within a 3+1 model, we place constraints on the mixing angles $\theta_{24}, Comment: 8 pages, 4 figures

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of $6.05\times10^{20}$ protons-on-target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal mixing ($\theta_{23} = \pi/4$). Assuming the normal mass hierarchy, we find $\Delta m^2 = (2.67 \pm 0.11)\times 10^{-3}$ eV$^2$ and $\sin^2 \theta_{23}$ at the two statistically degenerate values $0.404^{+0.030}_{-0.022}$ and $0.624^{+0.022}_{-0.030}$, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6 $\sigma$ significance., Comment: 7 pages, 3 figures

NOvA is a two-detector long-baseline neutrino oscillation experiment using Fermilab’s 700 kW NuMI muon neutrino beam. With a total exposure of 8.85×1020 +12.33×1020 protons on target delivered to NuMI in the neutrino + antineutrino beam mode (78% more antineutrino data than in 2018), the experiment has made a 4.4q-significant observation of the ve appearance in a vм beam, measured oscillation parameters |Δm232|, sin2O23, and excluded most values near бCP = п/2 for the inverted neutrino mass hierarchy by more than 3q.

We designed and evaluated an innovative computer-aided-learning environment based on the on-line integration of computer controlled medical diagnostic devices and a medical information system for use in the preclinical medical physics education of medical students. Our learning system simulates the actual clinical environment in a hospital or primary care unit. It uses a commercial medical information system for on-line storage and processing of clinical type data acquired during physics laboratory classes. Every student adopts two roles, the role of 'patient' and the role of 'physician'. As a 'physician' the student operates the medical devices to clinically assess 'patient' colleagues and records all results in an electronic 'patient' record. We also introduced an innovative approach to the use of supportive education materials, based on the methods of adaptive e-learning. A survey of student feedback is included and statistically evaluated. The results from the student feedback confirm the positive response of the latter to this novel implementation of medical physics and informatics in preclinical education. This approach not only significantly improves learning of medical physics and informatics skills but has the added advantage that it facilitates students' transition from preclinical to clinical subjects.

Collaborative Action provides a novel approach to modeling interaction among users and machines and IT-mediated collaboration among people to solve problems. CoAct extends the notions of affordance and moves away from idiosyncratic, subjective mental models of the world to the notion that actors with similar capacities to act can potentially discern similar action possibilities in the world. It changes the direction from discovery and alignment of internal representations to mutual attunement of collaborators to build sufficient capabilities, share informational structures, and calibrate selectivity to achieve shared affordances. CoAct has the potential to influence such diverse areas as usability engineering, information overload, and group decision making. CoAct can be used at multiple levels of granularity, from fine granularity of a single interaction to tracking intermediate progress and results of a set of interactions. Propositions based on CoAct are presented. An initial experiment provides some support for an affordance-based approach to information sharing/design.

The more collaborative enterprises are, the better they perform. However, current collaboration technologies do not contribute as much as expected to collaboration quality. Collaboration technology seems to be stuck in just overcoming the limitation of people not being in the same place at the same time. Real time communications are supported through such things as web-conferencing and instant messaging, while email, wikis, and web-based repositories provide the electronic equivalent of the shared file cabinet. Although some technologies support workflow and project management to a degree, there is little support for the joint development lifecycle of planning, creating, evaluating, negotiating, and consolidating group work. Focusing broadly on collaboration challenges highlights limitations of current technology and can help provide direction for the kinds of information technology that will be needed to bridge the IT support gap to meet current and future collaboration challenges.

Sensemaking involves incomplete discovery, inaccurate interpretation, and imperfect action that will fail in someway and likely alter the situation in some unknowable way. Sensemaking demands intense, deep collaboration with participating agents, who many times are physically distributed and come from different groups and organizations. Incorporating collaboration functionality in a piecemeal approach in different ways as add-ons within a portal-based architecture can place heavy demands on users to learn, organizations to train, and ultimately limit the potential of collaboration technology to achieve organizational goals. It is proposed that individual and group sensemaking is a better starting point from which to build architectures to mitigate socio-cognitive limitations of participating agents collaborating to make sense of things. Three levels of Collaboration Envelopes™ are presented and architectural considerations presented to guide development of technology to better support collaborative sensemaking.

This article provides an introduction to the special issue on Expanding the Boundaries of E-Collaboration. It presents an operational definition of the term e-collaboration, and a historical review of the development of e-collaboration tools and related academic research. That is followed by an introductory development of the notion of e-collaboration boundaries. The article concludes with a summarized discussion of the articles published in the special issue.

This paper explores how group cognition can provide a basis for understanding knowledge creation and sharing that does not depend on the assumption of extant internal representations that filter sense‐data. Literature from a wide variety of disciplines is synthesized to provide an ecologically‐oriented model of group cognition. Group cognition means moving away from idiosyncratic, subjective mental models of the world to the notion that agents with similar capacities to act can potentially discern similar action possibilities in the world. It changes the direction from discovery and alignment of mental models to selectivity calibration and informational structure sharing. “What one thinks” at a given moment is dependent on boundary objects available at the moment that predominately originate with human actors. Therefore, in this way, one’s cognition is predominately group cognition. Based on the breadth of the topic, this paper must be considered a work‐in‐progress, a snapshot of the exploration of such a complex subject. It provides an alternate view of knowledge creation and sharing as the basis for incorporating more effective collaboration functionality into technologies that support joint work. This paper challenges long‐held views of extant internal representations that filter sense‐data and offers a radically different ecological‐based model of group cognition.

Mobile technology research focuses on supporting the individual mobile worker. CCSW research has primarily focused on supporting distributed, but fixed‐site workers. This research bridges both research foci by expanding to include mobile, anytime, anyplace support. The VLab (Virtual laboratory) provides anytime, anyplace process support for mobile software development teams. A longitudinal evaluation of group interactions in multiple extant teams establishes a baseline that helps to identify process support requirements. This baseline can be used to judge the effect of introducing process support technology that addresses specific context variables in group interactions.

Describes how, in ill‐defined, emerging situations, team members struggle to make sense of the situation, react to stimuli from the external environment, and interact with each other and human artefacts to develop an interpretation of the environment. Presents a general model of this process, lessons derived from experiences in trying to support it, and issues for future development.

Mobile technology research focuses on supporting the individual mobile worker. Computer supported co‐operative work research has primarily focused on supporting distributed, but fixed‐site workers. Bridges both research foci by expanding to include mobile, any‐time, any‐place support. The complementary goal is to investigate better ways to prepare future team members for the new demands in the workplace. The VLab (Virtual laboratory) provides any‐time, any‐place process support for mobile software development teams. Presents a model that focuses on the processes involved in complex systems development and learning, and research propositions to evaluate mobile any‐time, any‐place support. Baseline measurements have been obtained and early results support the value of mobile group support technology.

Collaborative Action provides a novel approach to modeling interaction among users and machines and IT-mediated collaboration among people to solve problems. CoAct extends the notions of affordance and moves away from idiosyncratic, subjective mental models of the world to the notion that actors with similar capacities to act can potentially discern similar action possibilities in the world. It changes the direction from discovery and alignment of internal representations to mutual attunement of collaborators to build sufficient capabilities, share informational structures, and calibrate selectivity to achieve shared affordances. CoAct has the potential to influence such diverse areas as usability engineering, information overload, and group decision making. CoAct can be used at multiple levels of granularity, from fine granularity of a single interaction to tracking intermediate progress and results of a set of interactions. Propositions based on CoAct are presented. An initial experiment provides some support for an affordance-based approach to information sharing/design.

Computer Aided Software Engineering (CASE) has been receiving increasing attention because of its potential for substantial productivity improvement of software development. Yet only about 24% of companies use these tools. Arguments have been made that CASE tools are difficult to learn and use. We conducted two experiments with subjects who were both students and professional analysts to evaluate how easy it is for first time users to learn and a CASE tools to draw Data Flow Diagrams (DFDs).We found a typical CASE tool was easy to learn and use for developing correct, complete, balanced and readable DFDs. These experiments provide support for providing training in the structured technique before introducing the CASE tool based on the technique. It is proposed that failure to understand the technique may be translated into perceived failure of the CASE technology, and one reason for the limited use of CASE in organizations.

The ATP - Mg P i carrier in liver mitochondria is activated by micromolar Ca2+ and mediates net adenine nucleotide transport into and out of the mitochondrial matrix. The purpose of this study was to characterize certain features of ATP - Mg P i carrier activity that are essential for understanding how the mitochondrial adenine nucleotide content is regulated. The relative importance of ATP and ADP as transport substrates was investigated using specific trap assays to measure their separate rates of carrier-mediated efflux with Pi as the external counterion. Under energized conditions ATP efflux accounted for 88% of total ATP + ADP efflux. With oligomycin present to lower the matrix ATP ADP ratio, ATP efflux was eliminated and ADP efflux was relatively unaffected. Mg2+ was stoichiometrically required for ATP influx and is probably transported simultaneously with ATP. Ca2+ and Mn2+ could substitute for the stoichiometric Mg2+ requirement. ADP influx and Pi-induced adenine nucleotide efflux were unaffected by external Mg2+. Experiments with Pi analogues suggested that Pi is transported as the divalent anion, HPO42−. The results show that ATP-Mg and divalent Pi are the major transport substrates; the most probable transport mechanism for the ATP - Mg P i carrier is an electroneutral exchange. The results are consistent with the hypothesis that the direction and magnitude of net adenine nucleotide movements are determined mainly by the (ATP-Mg)2− and HPO42− concentration gradients across the inner mitochondrial membrane.

This study links end-user computer education to user satisfaction. A questionnaire was designed and employed to evaluate the impact of education and training on user information satisfaction. The subjects, who are employed in a variety of organizations, were queried prior to and after having completed a specially designed course in the management of information systems. After the educational experience, an increase in total user satisfaction was perceived by the subjects. The study demonstrates, however, that the connection between total satisfaction and education must be qualified by the caliber of the services rendered by Information Systems (IS) and the quality of the information product.

Compared to a decade ago, when the first comprehensive study was done in software maintenance, many changes have occurred in the practice of system development. Longitudinal data were obtained by using the same survey instrument, updated to reflect current practices, and sampling the same population. Comparing the current with 1977 results has helped to identify the persistent problems and issues as well as the emerging problems and issues. One of the important, but somewhat disturbing, conclusions is that maintenance problems are pretty much the same as during the 1970s (except for minor changes), despite advances made in structured methodologies and techniques. In terms of specific problems, personnel problems of maintenance programmers, i.e. turnover and availability, and programmer effectiveness problems, i.e. skills, motivation and productivity, have shown a rise, while problems associated with users' knowledge of computer systems have declined.

An experiment was conducted to test the effectiveness of two popular knowledge representation schemes as communication vehicles between the human expert and the knowledge engineer. Validation by the human expert of the knowledge encapsulated depends upon how well the expert understands and interprets a representation scheme. A between-group experiment was conducted. Each group received two treatments of the same representation technique, with the second treatment slightly more complex that the first. All the scores for the Semantic Network representations were higher than that obtained for the Predicate Logic representations; and the Semantic Network were clearly better for comprehension and conceptualization tasks. The results demonstrate some of the weaknesses of Predicate Logic and some of the strenths of Semantic Networks as communication tools during the validation process.

Adenine nucleotide transport over the carboxyatractyloside-insensitive ATP-Mg/Pi carrier was assayed in isolated rat liver mitochondria with the aim of investigating a possible regulatory role for Ca2+ on carrier activity. Net changes in the matrix adenine nucleotide content (ATP + ADP + AMP) occur when ATP-Mg exchanges for Pi over this carrier. The rates of net accumulation and net loss of adenine nucleotides were inhibited when free Ca2+ was chelated with EGTA and stimulated when buffered [Ca2+]free was increased from 1.0 to 4.0 microM. The unidirectional components of net change were similarly dependent on Ca2+; ATP influx and efflux were inhibited by EGTA in a concentration-dependent manner and stimulated by buffered free Ca2+ in the range 0.6-2.0 microM. For ATP influx, increasing the medium [Ca2+]free from 1.0 to 2.0 microM lowered the apparent Km for ATP from 4.44 to 2.44 mM with no effect on the apparent Vmax (3.55 and 3.76 nmol/min/mg with 1.0 and 2.0 microM [Ca2+]free, respectively). Stimulation of influx and efflux by [Ca2+]free was unaffected by either ruthenium red or the Ca2+ ionophore A23187. Calmodulin antagonists inhibited transport activity. In isolated hepatocytes, glucagon or vasopressin promoted an increased mitochondrial adenine nucleotide content. The effect of both hormones was blocked by EGTA, and for vasopressin, the effect was blocked also by neomycin. The results suggest that the increase in mitochondrial adenine nucleotide content that follows hormonal stimulation of hepatocytes is mediated by an increase in cytosolic [Ca2+]free that activates the ATP-Mg/Pi carrier.

Usually, the action researcher is someone who is external to the organization, provides expertise in an organizational intervention, and systematically evaluates the intervention to gain knowledge from the action. The responsibility for the research role by researcher and practitioner within action research can vary along a continuum from where the researcher takes full responsibility for research-oriented tasks to where the researcher coaches the practitioner in fulfilling research-oriented tasks. This chapter explores the end of the continuum where the inside practitioner is provided with the theory and research structure to fulfill more of the research-oriented tasks. The ill-structured problem domain of business planning is used to illustrate. Executives, who are students within an Executive MBA Program and are also participants in organizational interventions, fulfill the role of insider-as-researcher. Results indicate that insider action researchers can provide sensitive data to which outsider action researchers may not have access and are capable of systematically evaluating organizational interventions.

The authors examine the most frequently used methods for system development. Two development methodologies and over 15 techniques are examined for their applicability during different phases of the system development life cycle, for different types of systems, and for different levels of structure in the problem domain. The results obtained support the use of a contingency approach in the selection of methods for system development. >

There is little empirical evidence to support the value of information systems education and training. While IS training is conducted because of its direct impact on the accretion of skills, the lack of empirical evidence for the value of information systems education limits resource allocation for it. As organizations employ information technology which is more difficult to justify using standard cost/benefit methods, user information satisfaction (UIS) is becoming a useful metric to measure the business value of IT. In two multi-cultural field experiments it was found that information systems education caused statistically significant affects in UIS. In general, after viewing a video on the IS development process, end users became more satisfied with the information product and less satisfied with some aspects of IS support and staff, especially, the usual education and training provided.

Within many domains, complexity encompasses many nuances of ill-definition, fluidity, organizational variation, uncertainty, conflicting constraints, and multiple solutions. Responses to these areas of complexity necessitate the social construction of knowledge among various multidisciplinary team members. Group Cognition is offered as the basis of all cognition and is explained as a combination of Distributed and Coordinated Cognition that directly affects the creation/recreation of distributed and similar knowledges within a team.

This study investigated whether immobilization-induced hyposensitivity to d-tubocurarine (dTC), up-regulation of acetylcholine receptors (AChRs) and changes in fiber size and motor endplate size persist indefinitely and whether they are causally related. Unilateral disuse of the tibialis muscle was produced in adult rats by pinning the knee and ankle joints at 90 degrees flexion. The contralateral unpinned and a separate group of sham-pinned legs served as controls. After 7, 14 or 28 days of disuse, the in vivo dose of dTC that produced 50% depression of nerve-evoked twitch (ED50) in the tibialis muscle increased 3.0-, 3. 2- and 2.1-fold (P.05), and membrane AChRs increased 6.0- (P. 05), 6.3- (P.05) and 1.2-fold (P.395) relative to control, respectively. Disuse caused muscle fiber atrophy (P.01) but did not affect endplate size. Hence, the ratio of endplate size to fiber size increased. There was a transient increase in gene expression of all (including de novo expression of the gamma) subunits of the AChR, peaking at day 7 and returning to normal by day 28 of immobilization. The ED50 of dTC correlated directly with AChRs (R2 = 0.51; P.0001) or the ratio of endplate size to fiber size (R2 = 0. 30; P.001), and inversely with fiber size (R2 = 0.43, P.0001). It is proposed that acting together, but not singly, the changes in AChRs, fiber size and relative endplate size contribute to the magnitude and time course of the resistance to dTC produced by chronic disuse.

Nosek, M. T., and J. A. J. Martyn.Na+channel and acetylcholine receptor changes in muscle at sites distant from burns do not simulate denervation. J. Appl. Physiol. 82(4): 1333–1339, 1997.—Muscle weakness and aberrant responses to neuromuscular relaxants after burn injury are associated with upregulation of acetylcholine receptors (AChRs). Typically, these functional, pharmacological, and biochemical changes occur after denervation, in which transcriptionally mediated qualitative changes in AChRs and Na+channels and of myogenic regulatory proteins MyoD and myogenin also occur. This study in rats, by an examination of changes in the above-enumerated proteins or their transcripts in the gastrocnemius muscle distant from the burn, verifies whether a denervation-like state exists after burns. Scatchard analysis of [3H]saxitoxin binding revealed no changes in the affinity ( Kd) and total number (Bmax) of Na+channels between control and burn-injured animals at both 7 and 14 days after injury. The mRNA levels of the immature proteins, SkM2 of the Na+channels and the γ-subunits of AChRs, the increase of which is pathognomic of denervation, were assessed by Northern analysis and were unchanged. The transcripts of mature Na+channels, SkM1, were significantly increased at day 14after the burn (1.24 ± 0.10 in burn-injured vs. 1.06 ± 0.12 in sham animals, arbitrary units, P= 0.006). Although MyoD levels were increased in burn-injured animals at 14 days (0.21 ± 0.02 vs. 0.15 ± 0.07 arbitrary units, P = 0.05), myogenin levels were unaltered. The absence of changes in AChR transcripts, including α-, δ-, and γ-subunits, indicates that the upregulation of AChR in burns is not transcriptionally mediated. The unaltered levels of transcripts of myogenin, SkM2 of Na+channels and γ-subunit of AChR, confirm that there is no denervation-like prejunctional (nerve-related) component to explain the muscle weakness or the upregulation of AChRs at sites distant from burns.