Colorado State University Pueblo

Recent advances in three dimensional (3D) printing technology that allow multiple materials to be printed within each layer enable the creation of materials and components with precisely controlled heterogeneous microstructures. In addition, active materials, such as shape memory polymers, can be printed to create an active microstructure within a solid. These active materials can subsequently be activated in a controlled manner to change the shape or configuration of the solid in response to an environmental stimulus. This has been termed 4D printing, with the 4th dimension being the time-dependent shape change after the printing. In this paper, we advance the 4D printing concept to the design and fabrication of active origami, where a flat sheet automatically folds into a complicated 3D component. Here we print active composites with shape memory polymer fibers precisely printed in an elastomeric matrix and use them as intelligent active hinges to enable origami folding patterns. We develop a theoretical model to provide guidance in selecting design parameters such as fiber dimensions, hinge length, and programming strains and temperature. Using the model, we design and fabricate several active origami components that assemble from flat polymer sheets, including a box, a pyramid, and two origami airplanes. In addition, we directly print a 3D box with active composite hinges and program it to assume a temporary flat shape that subsequently recovers to the 3D box shape on demand.

The energy spectrum of cosmic rays above $2.5\ifmmode\times\else\texttimes\fi{}{10}^{18}\text{ }\mathrm{eV}$, derived from 20 000 events recorded at the Pierre Auger Observatory, is described. The spectral index $\ensuremath{\gamma}$ of the particle flux, $J\ensuremath{\propto}{E}^{\ensuremath{-}\ensuremath{\gamma}}$, at energies between $4\ifmmode\times\else\texttimes\fi{}{10}^{18}\text{ }\mathrm{eV}$ and $4\ifmmode\times\else\texttimes\fi{}{10}^{19}\text{ }\mathrm{eV}$ is $2.69\ifmmode\pm\else\textpm\fi{}0.02(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{syst})$, steepening to $4.2\ifmmode\pm\else\textpm\fi{}0.4(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{syst})$ at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

Chemical and physical processes driven by multiphoton absorption make possible the fabrication of complex, 3D structures with feature sizes as small as 100 nm. Since its inception less than a decade ago, the field of multiphoton fabrication has progressed rapidly, and multiphoton techniques are now being used to create functional microdevices. In this Review we discuss the techniques and materials used for multiphoton fabrication, the applications that have been demonstrated, as well as those being pursued. We also consider the outlook for this field, both in the laboratory and in industrial settings.

We report a study of the distributions of the depth of maximum, ${X}_{\mathrm{max}}$, of extensive air-shower profiles with energies above $1{0}^{17.8}\text{ }\text{ }\mathrm{eV}$ as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the ${X}_{\mathrm{max}}$ measurement and provide parametrizations thereof as a function of energy. The energy dependence of the mean and standard deviation of the ${X}_{\mathrm{max}}$ distributions are compared to air-shower simulations for different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere.

Information Systems (IS) managers are under increasing pressure to justify the value and contribution of IS expenditures to the productivity, quality, and competitiveness of the organization. This paper examines the need for IS assessment and suggests a comprehensive IS assessment framework linked to organizational performance using existing IS assessment theory as a base and incorporating measurement concepts from other disciplines. The existing models of IS success are updated to include the emerging IS success dimensions of service quality and work group impact and provide a comprehensive method for organizing the various measures of IS success. In addition, many new measures from recent research are presented to supplement the lists supplied by previous research. Additional research is suggested to advance the IS assessment contingency theory. Such a theory has the potential to contribute to the quality and productivity of the IS function and the larger organization by providing feedback to manage and improve the IS function to better meet the needs of the organization.Request access from your librarian to read this article's full text.

Using the data taken at the Pierre Auger Observatory between December 2004 and December 2012, we have examined the implications of the distributions of depths of atmospheric shower maximum (${X}_{\mathrm{max}}$), using a hybrid technique, for composition and hadronic interaction models. We do this by fitting the distributions with predictions from a variety of hadronic interaction models for variations in the composition of the primary cosmic rays and examining the quality of the fit. Regardless of what interaction model is assumed, we find that our data are not well described by a mix of protons and iron nuclei over most of the energy range. Acceptable fits can be obtained when intermediate masses are included, and when this is done consistent results for the proton and iron-nuclei contributions can be found using the available models. We observe a strong energy dependence of the resulting proton fractions, and find no support from any of the models for a significant contribution from iron nuclei. However, we also observe a significant disagreement between the models with respect to the relative contributions of the intermediate components.

We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of $[505\ifmmode\pm\else\textpm\fi{}22(\mathrm{stat}{)}_{\ensuremath{-}36}^{+28}(\mathrm{syst})]\text{ }\text{ }\mathrm{mb}$ is found.

An alpha-theta brainwave biofeedfack training program was applied as a novel treatment technique for chronic alcoholics. Following a temperature biofeedback pretraining phase, experimental subjects completed 15 30-min sessions of alpha-theta biofeedback training. Compared to a nonalcoholic control group and a traditionally treated alcoholic control group, alcoholics receiving brainwave training (BWT) showed significant increases in percentages of EEG record in alpha and theta rhythms, and increased alpha rhythm amplitudes. Alcoholics receiving BWT showed a gradual increase in alpha and theta brain rhythms across the 15 experimental sessions. These experimentally treated alcoholics showed sharp reductions in self-assessed depression (Beck's Depression Inventory) compared to the control groups. Alcoholics receiving standard medical treatment (abstinence, group psychotherapy, antidepressants) showed a significant elevation in serum beta-endorphin levels at the conclusion of the experiment. This neuropeptide is an index of stress and a stimulant of caloric (e.g., ethanol) intake. Application of brainwave treatment, a relaxation therapy, appears to counteract the increase in circulating beta-endorphin levels seen in the control group of alcoholics. 13-month follow-up data indicate sustained prevention of relapse in alcoholics that completed alpha-theta brainwave training.

The Pierre Auger collaboration reports new results bearing on the composition of cosmic rays. The muon number of air showers, created by cosmic rays and measured by the collaboration, is intriguingly at odds with all theoretical models, posing a challenge to our current understanding of the mass composition of cosmic rays.

We studied 199 working adults from a cross section of organizations in the United States to examine the relationship between positive psychological capital and organizational identity on employee deviance and organizational citizenship behaviors. Organizational identity was found to moderate the relationship between psychological capital (PsyCap) and both employee deviance and organizational citizenship behaviors such that employees highest in PsyCap and most strongly identified with the organization were most likely to engage in organizational citizenship behaviors and least likely to engage in deviance behaviors. We discuss implications for research and practice in the areas of PsyCap and employee identification with the organization.

We analyze the distribution of arrival directions of ultra-high energy cosmic rays recorded at the Pierre Auger Observatory in 10 years of operation. The data set, about three times larger than that used in earlier studies, includes arrival directions with zenith angles up to $80^\circ$, thus covering from $-90^\circ$ to $+45^\circ$ in declination. After updating the fraction of events correlating with the active galactic nuclei (AGNs) in the Véron-Cetty and Véron catalog, we subject the arrival directions of the data with energies in excess of 40 EeV to different tests for anisotropy. We search for localized excess fluxes and for self-clustering of event directions at angular scales up to $30^\circ$ and for different threshold energies between 40~EeV and 80~EeV. We then look for correlations of cosmic rays with celestial structures both in the Galaxy (the Galactic Center and Galactic Plane) and in the local Universe (the Super-Galactic Plane). We also examine their correlation with different populations of nearby extragalactic objects: galaxies in the 2MRS catalog, AGNs detected by Swift-BAT, radio galaxies with jets and the Centaurus~A galaxy. None of the tests shows a statistically significant evidence of anisotropy. The strongest departures from isotropy (post-trial probability ${\sim}1.4$\%) are obtained for cosmic rays with $E>58$~EeV in rather large windows around Swift AGNs closer than 130~Mpc and brighter than $10^{44}$~erg/s (18$^\circ$ radius) and around the direction of Centaurus~A (15$^\circ$ radius).

The Pierre Auger Collaboration reports on its search for ultra high energy (UHE) neutrinos in the EeV range, three orders of magnitude above the highest energy neutrino events reported by IceCube. Analyzing over 9 years of data, the collaboration found no events, setting the strictest limits to date on the diffuse flux of UHE neutrinos.

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ at EeV energies. Assuming an ${E}_{\ensuremath{\nu}}^{\ensuremath{-}2}$ differential energy spectrum the limit set at 90% C.L. is ${E}_{\ensuremath{\nu}}^{2}d{N}_{{\ensuremath{\nu}}_{\ensuremath{\tau}}}/d{E}_{\ensuremath{\nu}}<1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}\text{ }\text{ }\mathrm{GeV}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{sr}}^{\ensuremath{-}1}$ in the energy range $2\ifmmode\times\else\texttimes\fi{}{10}^{17}\text{ }\text{ }\mathrm{eV}<{E}_{\ensuremath{\nu}}<2\ifmmode\times\else\texttimes\fi{}{10}^{19}\text{ }\text{ }\mathrm{eV}$.

Electromyography is often used to infer the pattern of production of force by skeletal muscles. The interpretation of muscle function from the electromyogram (EMG) is challenged by the fact that factors such as type of muscle fiber, muscle length, and muscle velocity can all influence the relationship between electrical and mechanical activity of a muscle. Simultaneous measurements of EMG, muscle force, and fascicle length in hindlimb muscles of wild turkeys allow us to probe the quantitative link between force and EMG. We examined two features of the force-EMG relationship. First, we measured the relaxation electromechanical delay (r-EMD) as the time from the end of the EMG signal to time of the end of force. This delay varied with locomotor speed in the lateral gastrocnemius (LG); it was longer at slow walking speeds than for running. This variation in r-EMD was not explained by differences in muscle length trajectory, as the magnitude of r-EMD was not correlated with the velocity of shortening of the muscle during relaxation. We speculate that the longer relaxation times at slow walking speeds compared with running may reflect the longer time course of relaxation in slower muscles fibers. We also examined the relationship between magnitude of force and EMG across a range of walking and running speeds. We analyzed the force-EMG relationship during the swing phase separately from the force-EMG relationship during stance phase. During stance, force amplitude (average force) was linearly related to mean EMG amplitude (average EMG). Forces during swing phase were lower than predicted from the stance phase force-EMG relationship. The different force-EMG relationships during the stance and swing phases may reflect the contribution of passive structures to the development of force, or a nonlinear force-EMG relationship at low levels of muscle activity. Together the results suggest that any inference of force from EMG must be done cautiously when a broad range of activities is considered.

Noting the pervasiveness of videogames in American culture, the authors set out to examine the effects that playing videogames has on children. Thirty‐one children were matched on sex, randomly assigned to play either a violent (karate) videogame or a nonviolent (jungle vine swinging) videogame, and then observed during free play. The main results were that the children who had played the jungle swing videogame later played more with a jungle swing toy and that the children who played the violent videogame later showed more aggression. The authors interpreted the findings as an indication that young children who play videogames later tend to act similarly to how their videogame character acted.

Individuals increasingly rely on healthcare virtual support communities (HVSCs) for social support and companionship. While research provides interesting insights into the drivers of informational support in knowledge-sharing virtual communities, there is limited research on the antecedents of emotional support provision and companionship activities in HVSCs. The unique characteristics of HVSCs also justify the need to reexamine members’ voluntary provisions of help in such communities. This paper develops a model that examines the relationships between the structural, relational, and cognitive dimensions of social capital and the provision of informational and emotional support, and engagement in companionship activities in HVSCs. The model is tested based on data generated through an automated method that classifies and analyzes user-generated text in three healthcare virtual support communities (breast, prostate, and colorectal cancer). The results show that all three dimensions of social capital impact the provision of emotional support; both structural and relational capital facilitate engagement in companionship activities; and only cognitive capital enables the provision of informational support. Research and practical implications on the need to facilitate informational and emotional support provision and companionship activities in healthcare virtual support communities are discussed.

The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal.

OBJECTIVES: This study investigated the differential relationships between different types and sources of social support and physical and mental health. METHODS: Using data from the Normative Aging Study, 1,386 older men (median age = 62.7 years) were categorized into four groups separately for frequency of interaction with networks and perceived support. RESULTS: More than half the sample reported high levels of support from both sources. One-way ANOVAs revealed that those with high perceived support from both sources reported better physical health and fewer depressive symptoms than those with low support from both sources or high support from family alone. Similarly, those with high perceived support from both sources had lower levels of depressive symptoms than those with low support from both sources, but frequency of contact was unrelated to physical health. DISCUSSION: In general, those with high support from both family and friends reported the highest level of well-being.

The airline industry strives to maximize the revenue obtained from the sale of tickets on every flight. This is referred to as revenue management and it forms a crucial aspect of airline logistics. Ticket pricing, seat or discount allocation, and overbooking are some of the important aspects of a revenue management problem. Though ticket pricing is usually heavily influenced by factors beyond the control of an airline company, significant amount of control can be exercised over the seat allocation and the overbooking aspects. A realistic model for a single leg of a flight should consider multiple fare classes, overbooking of the flight, concurrent demand arrivals of passengers from the different fare classes, and class-dependent, random cancellations. Accommodating all these factors in one optimization model is a challenging task because that makes it a very large-scale stochastic optimization problem. Almost all papers in the existing literature either accommodate only a subset of these factors or use a discrete approximation in order to make the model tractable. We consider all these factors and cast the single leg problem as a semi-Markov Decision Problem (SMDP) under the average reward optimizing criterion over an infinite time horizon. We solve it using a stochastic optimization technique called Reinforcement Learning. Not only is Reinforcement Learning able to scale up to a huge state-space but because it is simulation-based it can also handle complex modeling assumptions such as the ones mentioned above. The state-space of the numerical test problem scenarios considered here is non-denumerable; its countable part being of the order of 109. Our solution procedure involves a multi-step extension of the SMART algorithm which is based on the one-step Bellman equation. Numerical results presented here show that our approach is able to outperform a heuristic, namely the nested version of the EMSR heuristic, which is widely used in the airline industry. We also present a detailed study of the sensitivity of some modeling parameters via a full factorial experiment.

The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed that cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially with respect to the shower axis, in agreement with predictions made by Askaryan who described radio emission from particle showers due to a negative charge excess in the front of the shower. Our results are compared to calculations which include the radiation mechanism induced by this charge-excess process.